In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in ped...In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in pediatric liver transpl-antation(LT),as well as the relationship between immune rejection after LT and DSA.Currently,LT remains the standard of care for pediatric patients with end-stage liver disease or severe acute liver failure.However,acute and chronic re-jection continues to be a significant cause of graft dysfunction and loss.HLA mismatch significantly reduces graft survival and increases the risk of acute rejection.Among them,D→R one-way mismatch at three loci was significantly related to graft-versus-host disease incidence after LT.The adverse impact of HLA-DSAs on LT recipients is already established.Therefore,the evaluation of HLA and DSA is crucial in pediatric LT.展开更多
BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay a...BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay and flow crossmatch(FCXM).The clinical significance of donor-specific antibodies(DSAs)detected by this method is still under investigation.AIM To report the impact of low-level pretransplant DSAs detected by the Luminex platform on the rates of acute rejection(AR),allograft function,and long-term graft survival.METHODS This retrospective study was conducted at the Immunology Department of Sindh Institute of Urology and Transplantation,Karachi,Pakistan between January 2013 and December 2022.During this period 2714 patients were transplanted.Out of these patients 78(2.9%)patients had low-level DSAs detected by the Luminex flow beads method and were negative by CDC and FCXM with their donors.All recipients received ABO-compatible live-related kidney transplants.All patients had a minimum follow-up of 1 year.Graft rejection rates,graft function,and patient and graft survival were analyzed.The estimated glomerular filtration rate was calculated by the full CKD-EPI formula.RESULTS The mean age of all recipients was 29.57±10.11 years and 34.53±9.09 years for the donors.In 48(61.5%)patients,the cause of end-stage kidney disease was unknown.DSA against HLA class I was detected in 36(46.1%)patients,class II in 35(44.8%)patients,and both class I and II in 7(8.9%)patients.AR episodes were encountered in 8(10.3%)cases.Seven(87.5%)had T cell mediated rejection(type IA)and one acute antibody-mediated rejection.Antibody status was re-evaluated at the time of biopsy-proven ARs.Five(62.5%)patients lost their DSAs,while three(37.5%)had persistent DSAs.The mean estimated glomerular filtration rate at 1 year was 80.56±27.48 mL/min/1.73 m2 and at the last follow-up 73.41±28.80 mL/min/1.73 m2.The 1-year and 10-year patient and graft survival rates were 99%and 79%and 95%and 75%,respectively.During the follow-up period,10(12.8%)patients died,8 patients had a functioning graft,and 2 patients had failed grafts.Eight patients died due to cardiopulmonary arrest,and two died due to sepsis with failed grafts.CONCLUSION Patients with pretransplant low-level DSAs on Luminex without CDC and FCXM reactivity had good allograft outcomes at 1 year and 10 years as long as they are induced with biological agents and given potent maintenance immunosuppressants.展开更多
Antibody-mediated rejection(AMR) caused by donorspecific anti-human leukocyte antigen antibodies(DSA) is widely accepted to be a risk factor for decreased graft survival after kidney transplantation. This entity also ...Antibody-mediated rejection(AMR) caused by donorspecific anti-human leukocyte antigen antibodies(DSA) is widely accepted to be a risk factor for decreased graft survival after kidney transplantation. This entity also plays a pathogenic role in other solid organ transplants as it appears to be an increasingly common cause of heart graft dysfunction and an emerging issue in lung transplantation. In contrast, the liver appears relatively resistant to DSA-mediated injury. This "immune-tolerance" liver property has been sustained by a low rate of liver graft loss in patients with preformed DSA and by the intrinsic liver characteristics that favor the absorption and elimination of DSA; however, alloantibody-mediated adverse consequences are increasingly being recognized, and several cases of acute AMR after ABO-compatible liver transplant(LT) have been reported. Furthermore, the availability of new solid-phase assays, allowing the detection of low titers of DSA and the refinement of objective diagnostic criteria for AMR in solid organ transplants and particularly in LT, have improved the recognition and management of this entity. A cost-effective strategy of DSA monitoring, avoidance of class Ⅱ human leukocyte antigen mismatching, judicious immunosuppression attached to a higher level of clinical suspicion of AMR, particularly in cases unresponsive to conventional antirejection therapy, can allow a rational approach to this threat.展开更多
Allo-antibodies, particularly when donor specific, are one of the most important factors that cause both early and late graft dysfunction. The authors review the current state of the art concerning this important issu...Allo-antibodies, particularly when donor specific, are one of the most important factors that cause both early and late graft dysfunction. The authors review the current state of the art concerning this important issue in renal transplantation. Many antibodies have been recognized as mediators of renal injury. In particular donorspecific-Human Leukocyte Antigens antibodies appear to play a major role. New techniques, such as solid phase techniques and Luminex, have revealed these antibodies from patient sera. Other new techniques have uncovered alloantibodies and signs of complement activation in renal biopsy specimens. It has been acknowledged that the old concept of chronic renal injury caused by calcineurine inhibitors toxicity should be replaced in many cases by alloantibodies acting against the graft. In addition, the number of patients on waiting lists with preformed anti-human leukocyte antigens(HLA) antibodies is increasing, primarily from patients with a history of renal transplant failure already been sensitized. We should distinguish early and late acute antibody-mediated rejection from chronic antibody-mediated rejection. The latter often manifets late during the course of the posttransplant period and may be difficult to recognize if specific techniques are not applied. Different therapeutic strategies are used to control antibody-induced damage.These strategies may be applied prior to transplantation or, in the case of acute antibody-mediated rejection, after transplantation. Many new drugs are appearing at the horizon; however, these drugs are far from the clinic because they are in phase Ⅰ-Ⅱ of clinical trials. Thus the pipeline for the near future appears almost empty.展开更多
AIM To analyze the clinical impact of preformed antiH LA-Cw vs antiH LA-A and/or-B donor-specific antibodies(DSA) in kidney transplantation.METHODS Retrospective study, comparing 12 patients transplanted with DSA excl...AIM To analyze the clinical impact of preformed antiH LA-Cw vs antiH LA-A and/or-B donor-specific antibodies(DSA) in kidney transplantation.METHODS Retrospective study, comparing 12 patients transplanted with DSA exclusively antiH LA-Cw with 23 patients with preformed DSA antiH LA-A and/or B.RESULTS One year after transplantation there were no differencesin terms of acute rejection between the two groups(3 and 6 cases, respectively in the DSA-Cw and the DSA-A-B groups; P = 1). At one year, eG FR was not significantly different between groups(median 59 mL /min in DSA-Cw group, compared to median 51 mL /min in DSA-A-B group, P = 0.192). Moreover, kidney graft survival was similar between groups at 5-years(100% in DSA-Cw group vs 91% in DSA-A-B group, P = 0.528). The sole independent predictor of antibody mediated rejection(AMR) incidence was DSA strength(HR = 1.07 per 1000 increase in MFI, P = 0.034). AMR was associated with shortened graft survival at 5-years, with 75% and 100% grafts surviving in patients with or without AMR, respectively(Log-rank P = 0.005).CONCLUSION Our data indicate that DSA-Cw are associated with an identical risk of AMR and impact on graft function in comparison with "classical" class I DSA.展开更多
Due to advances in modern medicine,liver transplantation has revolutionised the prognosis of many previously incurable liver diseases.This progress has largely been due to advances in immunosuppressant therapy.However...Due to advances in modern medicine,liver transplantation has revolutionised the prognosis of many previously incurable liver diseases.This progress has largely been due to advances in immunosuppressant therapy.However,despite the judicious use of immunosuppression,many liver transplant recipients still experience complications such as rejection,which necessitates diagnosis via invasive liver biopsy.There is a clear need for novel,minimally-invasive tests to optimise immunosuppression and improve patient outcomes.An emerging biomarker in this‘‘precision medicine’‘liver transplantation field is that of donorspecific cell free DNA.In this review,we detail the background and methods of detecting this biomarker,examine its utility in liver transplantation and discuss future research directions that may be most impactful.展开更多
BACKGROUND In a previous paper,we reported a high prevalence of donor-specific antibody(DSA)in pediatric patients with chronic rejection and expressed the need for confirmation of these findings in a larger cohort.AIM...BACKGROUND In a previous paper,we reported a high prevalence of donor-specific antibody(DSA)in pediatric patients with chronic rejection and expressed the need for confirmation of these findings in a larger cohort.AIM To clarify the importance of DSAs on long-term graft survival in a larger cohort of pediatric patients.METHODS We performed a retrospective analysis of 123 pediatric liver transplantation(LT)recipients who participated in yearly follow-ups including Luminex testing for DSA at our center.The cohort was split into two groups according to the DSA status(DSA-positive n=54,DSA-negative n=69).Groups were compared with regard to liver function,biopsy findings,graft survival,need for re-LT and immunosuppressive medication.RESULTS DSA-positive pediatric patients showed a higher prevalence of chronic rejection(P=0.01),fibrosis(P<0.001)and re-transplantation(P=0.018)than DSA-negative patients.Class II DSAs particularly influenced graft survival.Alleles DQ2,DQ7,DQ8 and DQ9 might serve as indicators for the risk of chronic rejection and/or allograft fibrosis.Mean fluorescence intensity levels and DSA number did not impact graft survival.Previous episodes of chronic rejection might lead to DSA development.CONCLUSION DSA prevalence significantly affected long-term liver allograft performance and liver allograft survival in our cohort of pediatric LT.Screening for class II DSAs in combination with assessment of protocol liver biopsies for chronic antibodymediated rejection improved early identification of patients at risk of graft loss.展开更多
Antibody-mediated rejection(AMR)is one of the major causes of graft loss after transplantation.Recently,the regulation of B cell differentiation and the prevention of donor-specific antibody(DSA)production have gained...Antibody-mediated rejection(AMR)is one of the major causes of graft loss after transplantation.Recently,the regulation of B cell differentiation and the prevention of donor-specific antibody(DSA)production have gained increased attention in transplant research.Herein,we established a secondary allogeneic in vivo skin transplant model to study the effects of romidepsin(FK228)on DSA.The survival of grafted skins was monitored daily.The serum levels of DSA and the number of relevant immunocytes in the recipient spleens were evaluated by flow cytometry.Then,we isolated and purified B cells from B6mouse spleens in vitro by magnetic bead sorting.The B cells were cultured with interleukin-4(IL-4)and anti-clusters of differentiation 40(CD40)antibody with or without FK228 treatment.The immunoglobulin G1(IgG1)and IgM levels in the supernatant were evaluated by enzyme-linked immunosorbent assay(ELISA).Quantitative reverse transcription-polymerase chain reaction(RT-q PCR)and western blotting were conducted to determine the corresponding levels of messenger RNA(mRNA)and protein expression in cultured cells and the recipient spleens.The results showed that FK228 significantly improved the survival of allogeneic skin grafts.Moreover,FK228 inhibited DSA production in the serum along with the suppression of histone deacetylase 1(HADC1)and HDAC2 and the upregulation of the acetylation of histones H2A and H3.It also inhibited the differentiation of B cells to plasma cells,decreased the transcription of positive regulatory domain-containing 1(Prdm1)and X-box-binding protein 1(Xbp1),and decreased the expression of phosphorylated inositol-requiring enzyme 1α(p-IRE1α),XBP1,and B lymphocyte-induced maturation protein-1(Blimp-1).In conclusion,FK228 could decrease the production of antibodies by B cells via inhibition of the IRE1α-XBP1 signaling pathway.Thus,FK228 is considered as a promising therapeutic agent for the clinical treatment of AMR.展开更多
The γc cytokines play an important role in proliferation and survival of T cells. Blocking the γc signals can cause the activated donor-reactive T cells losing the ability to proliferate, and getting into apoptosis ...The γc cytokines play an important role in proliferation and survival of T cells. Blocking the γc signals can cause the activated donor-reactive T cells losing the ability to proliferate, and getting into apoptosis pathway, which contributes to induction of the peripheral tolerance. In this study, we induced the transplant tolerance through blocking the γc in combination with donor-specific transfusion (DST) in the cardiac transplantation. Following DST, on the day 2, 4 and 6, C57BL/6 recipients received anti-γc monoclonal antibodies (mAbs) injection, and those in control group were not given anti-γc mAbs. On the day 7, Balb/c cardiac allografts were transplanted. All recipients in experimental group accepted cardiac allografts over 30 days, and two of them accepted allografts without rejection until sacrifice on the 120 day. Animals only receiving DST rejected grafts within 5 days, and the mice receiving cardiac transplantation alone rejected grafts within 9 days. Our study showed that blockade of γc signaling combined with DST significantly prolonged allograft survival, which was probably associated with inhibition of antigen-specific T-cell proliferation and induction of apoptosis.展开更多
Background:Increased risks have been found for patients undergoing liver transplantation due to the blood supply shortage following the ongoing coronavirus disease 2019(COVID-19)pandemic.Hence,exploring a method to al...Background:Increased risks have been found for patients undergoing liver transplantation due to the blood supply shortage following the ongoing coronavirus disease 2019(COVID-19)pandemic.Hence,exploring a method to alleviate this dilemma is urgent.This phase I,nonrandomized,prospective trial aimed to evaluate the safety and feasibility of using donor-specific red blood cell transfusion(DRBCT)as an urgent measurement to alleviate the blood supply shortage in deceased donor liver transplantation(DDLT).Methods:The outcomes of 26 patients who received DRBCT and 37 patients in the control group who only received 3rd party packed red blood cells(pRBCs)transfusion between May 2020 and January 2021 were compared.Results:Patients receiving DRBCT did not develop transfusion-related complications,and the incidence of postoperative infection was similar to that in the control group(23.1%vs.18.9%,P=0.688).Because the patients received the red blood cells from organ donors,the median volume of intraoperative allogeneic red blood cell transfusion from blood bank was 4.0 U(IQR 1.1-8.0 U)in the DRBCT group,which is significantly lower than that(7.5 U,IQR 4.0-10.0 U)in the control group(P=0.018).The peak aspartate aminotransferase(AST)level was significantly lower in the DRBCT group than in the control group(P=0.008)and so were the AST levels in the first two days after the operation(P=0.006 and P=0.033).Conclusions:DRBCT is a safe and effective procedure to lower the need for blood supply and is associated with a reduction in AST levels after transplantation.DRBCT is beneficial to patients receiving life-saving transplantation without sufficient blood supply during the COVID-19 pandemic.展开更多
Human leukocyte antigen(HLA)compatibility is very important for successful transplantation of solid organs.In this paper,we focused on the humoral arm of immunity in the clinical setting of organ transplantation:how H...Human leukocyte antigen(HLA)compatibility is very important for successful transplantation of solid organs.In this paper,we focused on the humoral arm of immunity in the clinical setting of organ transplantation:how HLA antibodies develop,how they can be detected,and what they can do to injure organ transplants.Specifically,we explore the technical perspectives of detecting donor-specific antibodies(DSA)in HLA laboratories,and use real-life clinical cases to explain the principles.Currently there are many tools in our HLA antibody detection toolbox:conventional cytotoxicity cross match,flow cross match,and solid phase assays using beads conjugated with single or multiple HLA antigens.Single antigen bead(SAB)assay is the most sensitive tool available for detecting HLA antibodies and assessing the immunological risk for organ transplant.However,there are intrinsic limitations to solid-phase assays and they are prone to both false negativity and importantly,false positivity.Denatured antigens on single antigen beads might be the most prominent source of false positive reactivity,and may have been underestimated by many HLA experts.No single assay is perfect and therefore multiple methods,including the less sensitive assays,should be employed to determine the clinical relevance of detected HLA antibodies.Thoughtful process,including knowledge of HLA systems,cross reactivity,epitopes,and the patient's clinical history should be employed to correctly interpret data.The clinical team should work closely with HLA laboratories to ensure accurate interpretation of information and optimal management of patients before and after organ transplantation.展开更多
Background:The complement system plays an important role in the immune response to transplantation,and the diagnostic significance of peritubular capillary(PTC)C4d deposition(C4d+)in grafts is controversial.The study ...Background:The complement system plays an important role in the immune response to transplantation,and the diagnostic significance of peritubular capillary(PTC)C4d deposition(C4d+)in grafts is controversial.The study aimed to fully investigate the risk factors for PTC C4d+and analyze its significance in biopsy pathology of kidney transplantation.Methods:This retrospective study included 124 cases of kidney transplant with graft biopsy and donor-specific antibody(DSA)testing from January 2017 to December 2019 in a single center.The effects of recipient pathological indicators,eplet mismatch(MM),and DSAs on PTC C4d+were examined using univariate and multivariate logistic regression analyses.Results:In total,35/124(28%)were PTC C4d+,including 21 with antibody-mediated rejection(AMR),eight with renal tubular injury,three with T cell-mediated rejection,one with glomerular disease,and two others.Univariate analysis revealed that DSAs(P<0.001),glomerulitis(P<0.001),peritubular capillaritis(P<0.001),and human leukocyte antigen(HLA)B eplet MM(P=0.010)were the influencing factors of PTC C4d+.According to multivariate analysis,DSAs(odds ratio[OR]:9.608,95%confidence interval[CI]:2.742–33.668,P<0.001),glomerulitis(OR:3.581,95%CI:1.246–10.289,P=0.018),and HLA B eplet MM(OR:1.166,95%CI:1.005–1.353,P=0.042)were the independent risk factors for PTC C4d+.In receiver operating characteristic curve analysis,the area under the curve was increased to 0.831 for predicting PTC C4d+when considering glomerulitis,DSAs,and HLA B eplet MM.The proportions of HLA I DSAs and PTC C4d+in active antibody-mediated rejection were 12/17 and 15/17,respectively;the proportions of HLA class II DSAs and PTC C4d+in chronic AMR were 8/12 and 7/12,respectively.Furthermore,the higher the PTC C4d+score was,the more serious the urinary occult blood and proteinuria of recipients at the time of biopsy.Conclusions:PTC C4d+was mainly observed in AMR cases.DSAs,glomerulitis,and HLA B eplet MM are the independent risk factors for PTC C4d+.展开更多
Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which...Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which recognize and bind to specific target antigens present within the transplanted kidney tissue.Upon binding,these DSAs commonly initiate activation of the complement system within the graft.The activation of the complement cascade sets off a powerful inflammatory response characterized by the recruitment and activation of immune cells,endothelial damage,and subsequent tissue injury.This inflammation underlies many clinical and histological manifestations of AMR,making complement activation a critical player in the disease process.Advancements in our understanding of how complement pathways contribute to kidney graft injury have opened new avenues for therapeutic intervention.Recent research has facilitated the development and application of novel therapies specifically designed to inhibit complement activation.Such targeted complement-inhibitory strategies have shown promise in improving graft outcomes by inhibiting complement-mediated damage and extending graft survival.This review comprehensively discusses the critical role of complement activation in inducing kidney graft injury with a focus on its role in AMR.By elucidating the detailed mechanisms and contributions of complement pathways,the review seeks to enhance the understanding necessary for developing targeted therapeutic interventions to prevent or treat AMR effectively.展开更多
BACKGROUND Antibody-mediated rejection following liver transplantation(LT)has been increasingly recognized,particularly with respect to the emergence of de novo donor-specific antibodies(DSAs)and their impact on graft...BACKGROUND Antibody-mediated rejection following liver transplantation(LT)has been increasingly recognized,particularly with respect to the emergence of de novo donor-specific antibodies(DSAs)and their impact on graft longevity.While substantial evidence for adult populations exists,research focusing on pediatric LT outcomes remains limited.AIM To investigate the prevalence of human leukocyte antigen(HLA)mismatches and DSA and evaluate their association with rejection episodes after pediatric LT.METHODS A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre,Brazil,between December 2013 and December 2023.Only patients who survived for>30 days after LT with at least one DSA analysis were included.DSA classes I and II and cross-matches were analyzed.The presence of de novo DSA(dnDSA)was evaluated at least 3 months after LT using the Luminex®single antigen bead method,with a positive reaction threshold set at 1000 MFI.Rejection episodes were confirmed by liver biopsy.RESULTS Overall,67 transplanted children were analyzed;61 received grafts from living donors,85%of whom were related to recipients.Pre-transplant DSA(class I or II)was detected in 28.3%of patients,and dnDSA was detected in 48.4%.The median time to DSA detection after LT was 19.7[interquartile range(IQR):4.3-35.6]months.Biopsyproven rejection occurred in 13 patients at follow-up,with C4d positivity observed in 5/13 Liver biopsies.The median time to rejection was 7.8(IQR:5.7-12.8)months.The presence of dnDSA was significantly associated with rejection(36%vs 3%,P<0.001).The rejection-free survival rates at 12 and 24 months were 76%vs 100%and 58%vs 95%for patients with dnDSA anti-DQ vs those without,respectively.CONCLUSION Our findings highlight the importance of incorporating DSA assessment into pre-and post-transplantation protocols for pediatric LT recipients.Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.展开更多
Acute humoral rejection （AHR） is uncommon after ABO- compatible liver transplantation. Herein, we report two cases of AHR treated with plasmapheresis and rituximab in two ABO-compatible liver-transplant patients wit...Acute humoral rejection （AHR） is uncommon after ABO- compatible liver transplantation. Herein, we report two cases of AHR treated with plasmapheresis and rituximab in two ABO-compatible liver-transplant patients with preformed anti-human leukocyte antigen donor-specific antibodies. Patient 1 experienced a biopsy-proven AHR at day 10 post-transplant. She was treated by steroid pulses, and OKT3. Because of persisting signs of biopsy-proven AHR at day 26, she was treated by plasmapheresis and rituximab. Uver enzyme levels did not improve, and she died on day 41. Patient 2 experienced a biopsy-proven AHR on day 10 post-transplant. She was treated by steroid pulses, plasmapheresis, and rituximab. Liver enzymes returned to within normal range 18 d after diagnosis. Uver biopsies, at 3 and 9 mo post-transplant, showed complete resolution of AHR. We conclude that plasmapheresis should be started as soon as AHR is diagnosed, and be associated with a B-cell depleting agent. Rituximab may be considered as a first-line therapy.展开更多
Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introducti...Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.展开更多
Antibody-mediated rejection(AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histoco...Antibody-mediated rejection(AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histocompatibility complex with the presence of HLA donor-specific antibodies, but also with antigens regarded as "minor", whose role in AMR has been demonstrated. Among them, antibodies against glutathione S-transferase T1 have been found in 100% of patients with de novo autoimmune hepatitis(dn AIH) when studied. In its latest update, the Banff Working Group for liver allograft pathology proposed replacing the term dn AIH with plasma cell(PC)-rich rejection. Antibodies to glutathione S-transferase T1(GSTT1) in null recipients of GSTT1 positive donors have been included as a contributory but nonessential feature of the diagnosis of PC-rich rejection. Also in this update, non-organ-specific anti-nuclear or smooth muscle autoantibodies are no longer included as diagnostic criteria. Although initially found in a proportion of patients with PC-rich rejection, the presence of autoantibodies is misleading since they are not diseasespecific and appear in many different contexts as bystanders. The cellular types and proportions of the inflammatory infiltrates in diagnostic biopsies have been studied in detail very recently. PC-rich rejection biopsies present a characteristic cellular profile with a predominance of T lymphocytes and a high proportion of PCs, close to 30%, of which 16.48% are Ig G4+. New data on the relevance of GSTT1-specific T lymphocytes to PC-rich rejection will be discussed in this review.展开更多
AIM To investigate the incidence, risk factors and clinical outcomes of acute antibody-mediated rejection(ABMR) after intestinal transplantation(ITx).METHODS A retrospective single-center analysis was performed to ide...AIM To investigate the incidence, risk factors and clinical outcomes of acute antibody-mediated rejection(ABMR) after intestinal transplantation(ITx).METHODS A retrospective single-center analysis was performed to identify cases of acute ABMR after ITx, based on the presence of donor-specific antibody(DSA), acute tissue damage, C4 d deposition, and allograft dysfunction.RESULTS Acute ABMR was identified in 18(10.3%) out of 175 intestinal allografts with an average occurrence of 10 d(range, 4-162) after ITx. All acute ABMR cases were presensitized to donor human leukocyte antigens class Ⅰand/or Ⅱ antigens with a detectable DSA. A positive cross-match was seen in 14(77.8%) cases and twelve of 18 patients(66.7%) produced newly-formed DSA following ITx. Histological characteristics of acute ABMR include endothelial C4 d deposits, interstitial hemorrhage, and severe congestion with focal fibrin thrombin in the lamina propria capillaries. Multivariate analysis identified a liver-free graft and high level of panel reactive antibodyas a significant independent risk factor. Despite initial improvement after therapy, eleven recipients(61.1%) lost transplant secondary to rejection. Of those, 9(50%) underwent graft removal and 4(22.2%) received second transplantation following acute ABMR. At an average follow-up of 32.3 mo(range, 13.3-76.4), 8(44.4%) recipients died.CONCLUSION Our results indicate that acute ABMR is an important cause of intestine graft dysfunction, particularly in a liver-exclusive graft and survivors are at an increased risk of developing refractory acute rejection and chronic rejection. More effective strategies to prevent and manage acute ABMR are needed to improve outcomes.展开更多
Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance,which is described by eventual imbalances or deregulation in the balance of cytokines,mediators,effectors,and regulatory cells ...Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance,which is described by eventual imbalances or deregulation in the balance of cytokines,mediators,effectors,and regulatory cells in the complex milieu of the liver.In this section,we will comment on the importance of donorspecific anti-human leukocyte antigen(HLA)antibodies(DSA)as well as the compatibility and pairings of HLA and killer-cell immunoglobulin-like receptor(KIR)genotypes in the evolution of liver transplantation.Thus,HLA compatibility,viral infections,and HLA-C/KIR combinations have all been linked to liver transplant rejection and survival.There have been reports of increased risk of acute and chronic rejection with ductopenia,faster graft fibrosis,biliary problems,poorer survival,and even de novo autoimmune hepatitis when DSAs are present in the recipient.Higher mean fluorescence intensity(MFI)values of the DSAs and smaller graft size were associated with poorer patient outcomes,implying that high-risk patients with preformed DSAs should be considered for selecting the graft placed and desensitization methods,according to the investigators.Similarly,in a combined kidney-liver transplant,a pretransplant with a visible expression of several DSAs revealed that these antibodies were resistant to treatment.The renal graft was lost owing to antibody-mediated rejection(AMR).The HLA antigens expressed by the transplanted liver graft influenced antibody elimination.Pathologists are increasingly diagnosing AMR in liver transplants,and desensitization therapy has even been employed in situations of AMR,particularly in patients with DSAs in kidney-hepatic transplants and high-class II MFI due to Luminex.In conclusion,after revealing the negative impacts of DSAs with high MFI,pretransplant virtual crossmatch techniques may be appropriate to improve evolution;however,they may extend cold ischemia periods by requiring the donor to be typed.展开更多
The introduction of novel immunosuppressive agents over the last two decades and the improvement of our diagnostic tools for early detection of antibodymediated injury offer us an opportunity, if not a mandate, to bet...The introduction of novel immunosuppressive agents over the last two decades and the improvement of our diagnostic tools for early detection of antibodymediated injury offer us an opportunity, if not a mandate, to better match the immunosuppression needs of the individual patients with side effects of the therapy. However, immunosuppressive regimens in the majority of programs remain mostly protocol-driven, with relatively little inter-program heterogeneity in certain areas of the world. Emerging data showing different outcomes with a particular immunosuppressive strategy in populations with varying immunological risks underscore a real potential for "personalized medicine" in renal transplantation. Studies demonstrating marked differences in the adverse-effect profiles of individual drugs including the risk for viral infections, malignancy and renal toxicity call for a paradigm shift away from a "one size fits all" approach to an individually tailored immunosuppressive therapy for renal transplant recipients, assisted by both screening for predictors of graft loss and paying close attention to dose or class-related adverse effects. Our paper explores some of the opportunities during the care of these patients. Potential areas of improvements may include:(1) a thorough assessment of immunological and metabolic risk profile of each renal transplant recipient;(2) screening for predictors of graft loss and early signs of antibody-mediated rejection with donor-specific antibodies, protocol biopsies and proteinuria(including close follow up of adverse effects with dose adjustments or conversions as necessary); and(3) increased awareness of the possible link between poor tolerance of a given drug at a given dose and non-adherence with the prescribed regimen. Altogether, these considerations may enable the most effective use of the drugs we already have.展开更多
文摘In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in pediatric liver transpl-antation(LT),as well as the relationship between immune rejection after LT and DSA.Currently,LT remains the standard of care for pediatric patients with end-stage liver disease or severe acute liver failure.However,acute and chronic re-jection continues to be a significant cause of graft dysfunction and loss.HLA mismatch significantly reduces graft survival and increases the risk of acute rejection.Among them,D→R one-way mismatch at three loci was significantly related to graft-versus-host disease incidence after LT.The adverse impact of HLA-DSAs on LT recipients is already established.Therefore,the evaluation of HLA and DSA is crucial in pediatric LT.
文摘BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay and flow crossmatch(FCXM).The clinical significance of donor-specific antibodies(DSAs)detected by this method is still under investigation.AIM To report the impact of low-level pretransplant DSAs detected by the Luminex platform on the rates of acute rejection(AR),allograft function,and long-term graft survival.METHODS This retrospective study was conducted at the Immunology Department of Sindh Institute of Urology and Transplantation,Karachi,Pakistan between January 2013 and December 2022.During this period 2714 patients were transplanted.Out of these patients 78(2.9%)patients had low-level DSAs detected by the Luminex flow beads method and were negative by CDC and FCXM with their donors.All recipients received ABO-compatible live-related kidney transplants.All patients had a minimum follow-up of 1 year.Graft rejection rates,graft function,and patient and graft survival were analyzed.The estimated glomerular filtration rate was calculated by the full CKD-EPI formula.RESULTS The mean age of all recipients was 29.57±10.11 years and 34.53±9.09 years for the donors.In 48(61.5%)patients,the cause of end-stage kidney disease was unknown.DSA against HLA class I was detected in 36(46.1%)patients,class II in 35(44.8%)patients,and both class I and II in 7(8.9%)patients.AR episodes were encountered in 8(10.3%)cases.Seven(87.5%)had T cell mediated rejection(type IA)and one acute antibody-mediated rejection.Antibody status was re-evaluated at the time of biopsy-proven ARs.Five(62.5%)patients lost their DSAs,while three(37.5%)had persistent DSAs.The mean estimated glomerular filtration rate at 1 year was 80.56±27.48 mL/min/1.73 m2 and at the last follow-up 73.41±28.80 mL/min/1.73 m2.The 1-year and 10-year patient and graft survival rates were 99%and 79%and 95%and 75%,respectively.During the follow-up period,10(12.8%)patients died,8 patients had a functioning graft,and 2 patients had failed grafts.Eight patients died due to cardiopulmonary arrest,and two died due to sepsis with failed grafts.CONCLUSION Patients with pretransplant low-level DSAs on Luminex without CDC and FCXM reactivity had good allograft outcomes at 1 year and 10 years as long as they are induced with biological agents and given potent maintenance immunosuppressants.
文摘Antibody-mediated rejection(AMR) caused by donorspecific anti-human leukocyte antigen antibodies(DSA) is widely accepted to be a risk factor for decreased graft survival after kidney transplantation. This entity also plays a pathogenic role in other solid organ transplants as it appears to be an increasingly common cause of heart graft dysfunction and an emerging issue in lung transplantation. In contrast, the liver appears relatively resistant to DSA-mediated injury. This "immune-tolerance" liver property has been sustained by a low rate of liver graft loss in patients with preformed DSA and by the intrinsic liver characteristics that favor the absorption and elimination of DSA; however, alloantibody-mediated adverse consequences are increasingly being recognized, and several cases of acute AMR after ABO-compatible liver transplant(LT) have been reported. Furthermore, the availability of new solid-phase assays, allowing the detection of low titers of DSA and the refinement of objective diagnostic criteria for AMR in solid organ transplants and particularly in LT, have improved the recognition and management of this entity. A cost-effective strategy of DSA monitoring, avoidance of class Ⅱ human leukocyte antigen mismatching, judicious immunosuppression attached to a higher level of clinical suspicion of AMR, particularly in cases unresponsive to conventional antirejection therapy, can allow a rational approach to this threat.
文摘Allo-antibodies, particularly when donor specific, are one of the most important factors that cause both early and late graft dysfunction. The authors review the current state of the art concerning this important issue in renal transplantation. Many antibodies have been recognized as mediators of renal injury. In particular donorspecific-Human Leukocyte Antigens antibodies appear to play a major role. New techniques, such as solid phase techniques and Luminex, have revealed these antibodies from patient sera. Other new techniques have uncovered alloantibodies and signs of complement activation in renal biopsy specimens. It has been acknowledged that the old concept of chronic renal injury caused by calcineurine inhibitors toxicity should be replaced in many cases by alloantibodies acting against the graft. In addition, the number of patients on waiting lists with preformed anti-human leukocyte antigens(HLA) antibodies is increasing, primarily from patients with a history of renal transplant failure already been sensitized. We should distinguish early and late acute antibody-mediated rejection from chronic antibody-mediated rejection. The latter often manifets late during the course of the posttransplant period and may be difficult to recognize if specific techniques are not applied. Different therapeutic strategies are used to control antibody-induced damage.These strategies may be applied prior to transplantation or, in the case of acute antibody-mediated rejection, after transplantation. Many new drugs are appearing at the horizon; however, these drugs are far from the clinic because they are in phase Ⅰ-Ⅱ of clinical trials. Thus the pipeline for the near future appears almost empty.
文摘AIM To analyze the clinical impact of preformed antiH LA-Cw vs antiH LA-A and/or-B donor-specific antibodies(DSA) in kidney transplantation.METHODS Retrospective study, comparing 12 patients transplanted with DSA exclusively antiH LA-Cw with 23 patients with preformed DSA antiH LA-A and/or B.RESULTS One year after transplantation there were no differencesin terms of acute rejection between the two groups(3 and 6 cases, respectively in the DSA-Cw and the DSA-A-B groups; P = 1). At one year, eG FR was not significantly different between groups(median 59 mL /min in DSA-Cw group, compared to median 51 mL /min in DSA-A-B group, P = 0.192). Moreover, kidney graft survival was similar between groups at 5-years(100% in DSA-Cw group vs 91% in DSA-A-B group, P = 0.528). The sole independent predictor of antibody mediated rejection(AMR) incidence was DSA strength(HR = 1.07 per 1000 increase in MFI, P = 0.034). AMR was associated with shortened graft survival at 5-years, with 75% and 100% grafts surviving in patients with or without AMR, respectively(Log-rank P = 0.005).CONCLUSION Our data indicate that DSA-Cw are associated with an identical risk of AMR and impact on graft function in comparison with "classical" class I DSA.
基金The University of Melbourne,Parkville 3000,VIC,Australia。
文摘Due to advances in modern medicine,liver transplantation has revolutionised the prognosis of many previously incurable liver diseases.This progress has largely been due to advances in immunosuppressant therapy.However,despite the judicious use of immunosuppression,many liver transplant recipients still experience complications such as rejection,which necessitates diagnosis via invasive liver biopsy.There is a clear need for novel,minimally-invasive tests to optimise immunosuppression and improve patient outcomes.An emerging biomarker in this‘‘precision medicine’‘liver transplantation field is that of donorspecific cell free DNA.In this review,we detail the background and methods of detecting this biomarker,examine its utility in liver transplantation and discuss future research directions that may be most impactful.
文摘BACKGROUND In a previous paper,we reported a high prevalence of donor-specific antibody(DSA)in pediatric patients with chronic rejection and expressed the need for confirmation of these findings in a larger cohort.AIM To clarify the importance of DSAs on long-term graft survival in a larger cohort of pediatric patients.METHODS We performed a retrospective analysis of 123 pediatric liver transplantation(LT)recipients who participated in yearly follow-ups including Luminex testing for DSA at our center.The cohort was split into two groups according to the DSA status(DSA-positive n=54,DSA-negative n=69).Groups were compared with regard to liver function,biopsy findings,graft survival,need for re-LT and immunosuppressive medication.RESULTS DSA-positive pediatric patients showed a higher prevalence of chronic rejection(P=0.01),fibrosis(P<0.001)and re-transplantation(P=0.018)than DSA-negative patients.Class II DSAs particularly influenced graft survival.Alleles DQ2,DQ7,DQ8 and DQ9 might serve as indicators for the risk of chronic rejection and/or allograft fibrosis.Mean fluorescence intensity levels and DSA number did not impact graft survival.Previous episodes of chronic rejection might lead to DSA development.CONCLUSION DSA prevalence significantly affected long-term liver allograft performance and liver allograft survival in our cohort of pediatric LT.Screening for class II DSAs in combination with assessment of protocol liver biopsies for chronic antibodymediated rejection improved early identification of patients at risk of graft loss.
基金supported by the National Natural Science Foundation of China(Nos.81873511 and 81471587)。
文摘Antibody-mediated rejection(AMR)is one of the major causes of graft loss after transplantation.Recently,the regulation of B cell differentiation and the prevention of donor-specific antibody(DSA)production have gained increased attention in transplant research.Herein,we established a secondary allogeneic in vivo skin transplant model to study the effects of romidepsin(FK228)on DSA.The survival of grafted skins was monitored daily.The serum levels of DSA and the number of relevant immunocytes in the recipient spleens were evaluated by flow cytometry.Then,we isolated and purified B cells from B6mouse spleens in vitro by magnetic bead sorting.The B cells were cultured with interleukin-4(IL-4)and anti-clusters of differentiation 40(CD40)antibody with or without FK228 treatment.The immunoglobulin G1(IgG1)and IgM levels in the supernatant were evaluated by enzyme-linked immunosorbent assay(ELISA).Quantitative reverse transcription-polymerase chain reaction(RT-q PCR)and western blotting were conducted to determine the corresponding levels of messenger RNA(mRNA)and protein expression in cultured cells and the recipient spleens.The results showed that FK228 significantly improved the survival of allogeneic skin grafts.Moreover,FK228 inhibited DSA production in the serum along with the suppression of histone deacetylase 1(HADC1)and HDAC2 and the upregulation of the acetylation of histones H2A and H3.It also inhibited the differentiation of B cells to plasma cells,decreased the transcription of positive regulatory domain-containing 1(Prdm1)and X-box-binding protein 1(Xbp1),and decreased the expression of phosphorylated inositol-requiring enzyme 1α(p-IRE1α),XBP1,and B lymphocyte-induced maturation protein-1(Blimp-1).In conclusion,FK228 could decrease the production of antibodies by B cells via inhibition of the IRE1α-XBP1 signaling pathway.Thus,FK228 is considered as a promising therapeutic agent for the clinical treatment of AMR.
基金supported by grants from the National Natural Sciences Foundation of China (No. 30500468 and 30700768)
文摘The γc cytokines play an important role in proliferation and survival of T cells. Blocking the γc signals can cause the activated donor-reactive T cells losing the ability to proliferate, and getting into apoptosis pathway, which contributes to induction of the peripheral tolerance. In this study, we induced the transplant tolerance through blocking the γc in combination with donor-specific transfusion (DST) in the cardiac transplantation. Following DST, on the day 2, 4 and 6, C57BL/6 recipients received anti-γc monoclonal antibodies (mAbs) injection, and those in control group were not given anti-γc mAbs. On the day 7, Balb/c cardiac allografts were transplanted. All recipients in experimental group accepted cardiac allografts over 30 days, and two of them accepted allografts without rejection until sacrifice on the 120 day. Animals only receiving DST rejected grafts within 5 days, and the mice receiving cardiac transplantation alone rejected grafts within 9 days. Our study showed that blockade of γc signaling combined with DST significantly prolonged allograft survival, which was probably associated with inhibition of antigen-specific T-cell proliferation and induction of apoptosis.
基金This study was supported by grants from the New Clinical Technology Project,West China Hospital,Sichuan University(Grant number:20HXJS012)Sichuan Province Key Research and Development Project(Grant number:2020YFS0134)National Clinical Research Center for Geriatrics,West China Hospital,Sichuan University(Grant number:Z2018B23).
文摘Background:Increased risks have been found for patients undergoing liver transplantation due to the blood supply shortage following the ongoing coronavirus disease 2019(COVID-19)pandemic.Hence,exploring a method to alleviate this dilemma is urgent.This phase I,nonrandomized,prospective trial aimed to evaluate the safety and feasibility of using donor-specific red blood cell transfusion(DRBCT)as an urgent measurement to alleviate the blood supply shortage in deceased donor liver transplantation(DDLT).Methods:The outcomes of 26 patients who received DRBCT and 37 patients in the control group who only received 3rd party packed red blood cells(pRBCs)transfusion between May 2020 and January 2021 were compared.Results:Patients receiving DRBCT did not develop transfusion-related complications,and the incidence of postoperative infection was similar to that in the control group(23.1%vs.18.9%,P=0.688).Because the patients received the red blood cells from organ donors,the median volume of intraoperative allogeneic red blood cell transfusion from blood bank was 4.0 U(IQR 1.1-8.0 U)in the DRBCT group,which is significantly lower than that(7.5 U,IQR 4.0-10.0 U)in the control group(P=0.018).The peak aspartate aminotransferase(AST)level was significantly lower in the DRBCT group than in the control group(P=0.008)and so were the AST levels in the first two days after the operation(P=0.006 and P=0.033).Conclusions:DRBCT is a safe and effective procedure to lower the need for blood supply and is associated with a reduction in AST levels after transplantation.DRBCT is beneficial to patients receiving life-saving transplantation without sufficient blood supply during the COVID-19 pandemic.
文摘Human leukocyte antigen(HLA)compatibility is very important for successful transplantation of solid organs.In this paper,we focused on the humoral arm of immunity in the clinical setting of organ transplantation:how HLA antibodies develop,how they can be detected,and what they can do to injure organ transplants.Specifically,we explore the technical perspectives of detecting donor-specific antibodies(DSA)in HLA laboratories,and use real-life clinical cases to explain the principles.Currently there are many tools in our HLA antibody detection toolbox:conventional cytotoxicity cross match,flow cross match,and solid phase assays using beads conjugated with single or multiple HLA antigens.Single antigen bead(SAB)assay is the most sensitive tool available for detecting HLA antibodies and assessing the immunological risk for organ transplant.However,there are intrinsic limitations to solid-phase assays and they are prone to both false negativity and importantly,false positivity.Denatured antigens on single antigen beads might be the most prominent source of false positive reactivity,and may have been underestimated by many HLA experts.No single assay is perfect and therefore multiple methods,including the less sensitive assays,should be employed to determine the clinical relevance of detected HLA antibodies.Thoughtful process,including knowledge of HLA systems,cross reactivity,epitopes,and the patient's clinical history should be employed to correctly interpret data.The clinical team should work closely with HLA laboratories to ensure accurate interpretation of information and optimal management of patients before and after organ transplantation.
基金the Clinical Research Award of the First Affiliated Hospital of Xi’an Jiaotong University,China(No.XJTU1AF-CRF-2018-026)the Natural Science Foundation of China(No.82070768).
文摘Background:The complement system plays an important role in the immune response to transplantation,and the diagnostic significance of peritubular capillary(PTC)C4d deposition(C4d+)in grafts is controversial.The study aimed to fully investigate the risk factors for PTC C4d+and analyze its significance in biopsy pathology of kidney transplantation.Methods:This retrospective study included 124 cases of kidney transplant with graft biopsy and donor-specific antibody(DSA)testing from January 2017 to December 2019 in a single center.The effects of recipient pathological indicators,eplet mismatch(MM),and DSAs on PTC C4d+were examined using univariate and multivariate logistic regression analyses.Results:In total,35/124(28%)were PTC C4d+,including 21 with antibody-mediated rejection(AMR),eight with renal tubular injury,three with T cell-mediated rejection,one with glomerular disease,and two others.Univariate analysis revealed that DSAs(P<0.001),glomerulitis(P<0.001),peritubular capillaritis(P<0.001),and human leukocyte antigen(HLA)B eplet MM(P=0.010)were the influencing factors of PTC C4d+.According to multivariate analysis,DSAs(odds ratio[OR]:9.608,95%confidence interval[CI]:2.742–33.668,P<0.001),glomerulitis(OR:3.581,95%CI:1.246–10.289,P=0.018),and HLA B eplet MM(OR:1.166,95%CI:1.005–1.353,P=0.042)were the independent risk factors for PTC C4d+.In receiver operating characteristic curve analysis,the area under the curve was increased to 0.831 for predicting PTC C4d+when considering glomerulitis,DSAs,and HLA B eplet MM.The proportions of HLA I DSAs and PTC C4d+in active antibody-mediated rejection were 12/17 and 15/17,respectively;the proportions of HLA class II DSAs and PTC C4d+in chronic AMR were 8/12 and 7/12,respectively.Furthermore,the higher the PTC C4d+score was,the more serious the urinary occult blood and proteinuria of recipients at the time of biopsy.Conclusions:PTC C4d+was mainly observed in AMR cases.DSAs,glomerulitis,and HLA B eplet MM are the independent risk factors for PTC C4d+.
文摘Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which recognize and bind to specific target antigens present within the transplanted kidney tissue.Upon binding,these DSAs commonly initiate activation of the complement system within the graft.The activation of the complement cascade sets off a powerful inflammatory response characterized by the recruitment and activation of immune cells,endothelial damage,and subsequent tissue injury.This inflammation underlies many clinical and histological manifestations of AMR,making complement activation a critical player in the disease process.Advancements in our understanding of how complement pathways contribute to kidney graft injury have opened new avenues for therapeutic intervention.Recent research has facilitated the development and application of novel therapies specifically designed to inhibit complement activation.Such targeted complement-inhibitory strategies have shown promise in improving graft outcomes by inhibiting complement-mediated damage and extending graft survival.This review comprehensively discusses the critical role of complement activation in inducing kidney graft injury with a focus on its role in AMR.By elucidating the detailed mechanisms and contributions of complement pathways,the review seeks to enhance the understanding necessary for developing targeted therapeutic interventions to prevent or treat AMR effectively.
基金approved by the Ethics and Research Committee of the Federal University of Health Sciences of Porto Alegre(UFCSPA)and the Santa Casa de Misericórdia de Porto Alegre Complex(ISCMPA)(approval numbers 3805918 and 3938979,respectively)the Brazilian Clinical Trials Registry(ReBec)under number RBR-3 gtcvjU111112367585.
文摘BACKGROUND Antibody-mediated rejection following liver transplantation(LT)has been increasingly recognized,particularly with respect to the emergence of de novo donor-specific antibodies(DSAs)and their impact on graft longevity.While substantial evidence for adult populations exists,research focusing on pediatric LT outcomes remains limited.AIM To investigate the prevalence of human leukocyte antigen(HLA)mismatches and DSA and evaluate their association with rejection episodes after pediatric LT.METHODS A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre,Brazil,between December 2013 and December 2023.Only patients who survived for>30 days after LT with at least one DSA analysis were included.DSA classes I and II and cross-matches were analyzed.The presence of de novo DSA(dnDSA)was evaluated at least 3 months after LT using the Luminex®single antigen bead method,with a positive reaction threshold set at 1000 MFI.Rejection episodes were confirmed by liver biopsy.RESULTS Overall,67 transplanted children were analyzed;61 received grafts from living donors,85%of whom were related to recipients.Pre-transplant DSA(class I or II)was detected in 28.3%of patients,and dnDSA was detected in 48.4%.The median time to DSA detection after LT was 19.7[interquartile range(IQR):4.3-35.6]months.Biopsyproven rejection occurred in 13 patients at follow-up,with C4d positivity observed in 5/13 Liver biopsies.The median time to rejection was 7.8(IQR:5.7-12.8)months.The presence of dnDSA was significantly associated with rejection(36%vs 3%,P<0.001).The rejection-free survival rates at 12 and 24 months were 76%vs 100%and 58%vs 95%for patients with dnDSA anti-DQ vs those without,respectively.CONCLUSION Our findings highlight the importance of incorporating DSA assessment into pre-and post-transplantation protocols for pediatric LT recipients.Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.
文摘Acute humoral rejection （AHR） is uncommon after ABO- compatible liver transplantation. Herein, we report two cases of AHR treated with plasmapheresis and rituximab in two ABO-compatible liver-transplant patients with preformed anti-human leukocyte antigen donor-specific antibodies. Patient 1 experienced a biopsy-proven AHR at day 10 post-transplant. She was treated by steroid pulses, and OKT3. Because of persisting signs of biopsy-proven AHR at day 26, she was treated by plasmapheresis and rituximab. Uver enzyme levels did not improve, and she died on day 41. Patient 2 experienced a biopsy-proven AHR on day 10 post-transplant. She was treated by steroid pulses, plasmapheresis, and rituximab. Liver enzymes returned to within normal range 18 d after diagnosis. Uver biopsies, at 3 and 9 mo post-transplant, showed complete resolution of AHR. We conclude that plasmapheresis should be started as soon as AHR is diagnosed, and be associated with a B-cell depleting agent. Rituximab may be considered as a first-line therapy.
文摘Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.
基金Supported by Andalusian government,Proyecto de Excelencia,No.CTS-7846Spanish Ministry of Economy,Instituto de Salud Carlos Ⅲ,No.11/857 and No.17/1403
文摘Antibody-mediated rejection(AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histocompatibility complex with the presence of HLA donor-specific antibodies, but also with antigens regarded as "minor", whose role in AMR has been demonstrated. Among them, antibodies against glutathione S-transferase T1 have been found in 100% of patients with de novo autoimmune hepatitis(dn AIH) when studied. In its latest update, the Banff Working Group for liver allograft pathology proposed replacing the term dn AIH with plasma cell(PC)-rich rejection. Antibodies to glutathione S-transferase T1(GSTT1) in null recipients of GSTT1 positive donors have been included as a contributory but nonessential feature of the diagnosis of PC-rich rejection. Also in this update, non-organ-specific anti-nuclear or smooth muscle autoantibodies are no longer included as diagnostic criteria. Although initially found in a proportion of patients with PC-rich rejection, the presence of autoantibodies is misleading since they are not diseasespecific and appear in many different contexts as bystanders. The cellular types and proportions of the inflammatory infiltrates in diagnostic biopsies have been studied in detail very recently. PC-rich rejection biopsies present a characteristic cellular profile with a predominance of T lymphocytes and a high proportion of PCs, close to 30%, of which 16.48% are Ig G4+. New data on the relevance of GSTT1-specific T lymphocytes to PC-rich rejection will be discussed in this review.
文摘AIM To investigate the incidence, risk factors and clinical outcomes of acute antibody-mediated rejection(ABMR) after intestinal transplantation(ITx).METHODS A retrospective single-center analysis was performed to identify cases of acute ABMR after ITx, based on the presence of donor-specific antibody(DSA), acute tissue damage, C4 d deposition, and allograft dysfunction.RESULTS Acute ABMR was identified in 18(10.3%) out of 175 intestinal allografts with an average occurrence of 10 d(range, 4-162) after ITx. All acute ABMR cases were presensitized to donor human leukocyte antigens class Ⅰand/or Ⅱ antigens with a detectable DSA. A positive cross-match was seen in 14(77.8%) cases and twelve of 18 patients(66.7%) produced newly-formed DSA following ITx. Histological characteristics of acute ABMR include endothelial C4 d deposits, interstitial hemorrhage, and severe congestion with focal fibrin thrombin in the lamina propria capillaries. Multivariate analysis identified a liver-free graft and high level of panel reactive antibodyas a significant independent risk factor. Despite initial improvement after therapy, eleven recipients(61.1%) lost transplant secondary to rejection. Of those, 9(50%) underwent graft removal and 4(22.2%) received second transplantation following acute ABMR. At an average follow-up of 32.3 mo(range, 13.3-76.4), 8(44.4%) recipients died.CONCLUSION Our results indicate that acute ABMR is an important cause of intestine graft dysfunction, particularly in a liver-exclusive graft and survivors are at an increased risk of developing refractory acute rejection and chronic rejection. More effective strategies to prevent and manage acute ABMR are needed to improve outcomes.
基金Instituto de Salud Carlos III,Spanish Ministry of Economy and Competitiveness,No.PI15/01370 and P19/01194and the European Union with the European Fund of Regional Development with the principle of“A manner to build Europe”.
文摘Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance,which is described by eventual imbalances or deregulation in the balance of cytokines,mediators,effectors,and regulatory cells in the complex milieu of the liver.In this section,we will comment on the importance of donorspecific anti-human leukocyte antigen(HLA)antibodies(DSA)as well as the compatibility and pairings of HLA and killer-cell immunoglobulin-like receptor(KIR)genotypes in the evolution of liver transplantation.Thus,HLA compatibility,viral infections,and HLA-C/KIR combinations have all been linked to liver transplant rejection and survival.There have been reports of increased risk of acute and chronic rejection with ductopenia,faster graft fibrosis,biliary problems,poorer survival,and even de novo autoimmune hepatitis when DSAs are present in the recipient.Higher mean fluorescence intensity(MFI)values of the DSAs and smaller graft size were associated with poorer patient outcomes,implying that high-risk patients with preformed DSAs should be considered for selecting the graft placed and desensitization methods,according to the investigators.Similarly,in a combined kidney-liver transplant,a pretransplant with a visible expression of several DSAs revealed that these antibodies were resistant to treatment.The renal graft was lost owing to antibody-mediated rejection(AMR).The HLA antigens expressed by the transplanted liver graft influenced antibody elimination.Pathologists are increasingly diagnosing AMR in liver transplants,and desensitization therapy has even been employed in situations of AMR,particularly in patients with DSAs in kidney-hepatic transplants and high-class II MFI due to Luminex.In conclusion,after revealing the negative impacts of DSAs with high MFI,pretransplant virtual crossmatch techniques may be appropriate to improve evolution;however,they may extend cold ischemia periods by requiring the donor to be typed.
文摘The introduction of novel immunosuppressive agents over the last two decades and the improvement of our diagnostic tools for early detection of antibodymediated injury offer us an opportunity, if not a mandate, to better match the immunosuppression needs of the individual patients with side effects of the therapy. However, immunosuppressive regimens in the majority of programs remain mostly protocol-driven, with relatively little inter-program heterogeneity in certain areas of the world. Emerging data showing different outcomes with a particular immunosuppressive strategy in populations with varying immunological risks underscore a real potential for "personalized medicine" in renal transplantation. Studies demonstrating marked differences in the adverse-effect profiles of individual drugs including the risk for viral infections, malignancy and renal toxicity call for a paradigm shift away from a "one size fits all" approach to an individually tailored immunosuppressive therapy for renal transplant recipients, assisted by both screening for predictors of graft loss and paying close attention to dose or class-related adverse effects. Our paper explores some of the opportunities during the care of these patients. Potential areas of improvements may include:(1) a thorough assessment of immunological and metabolic risk profile of each renal transplant recipient;(2) screening for predictors of graft loss and early signs of antibody-mediated rejection with donor-specific antibodies, protocol biopsies and proteinuria(including close follow up of adverse effects with dose adjustments or conversions as necessary); and(3) increased awareness of the possible link between poor tolerance of a given drug at a given dose and non-adherence with the prescribed regimen. Altogether, these considerations may enable the most effective use of the drugs we already have.
