Autoimmune hepatitis(AIH)is a liver disease of unknown cause characterized by hypergammaglobulinemia,typical or compatible liver histology,the absence of viral hepatitis and the production of autoantibodies.Anti-smoot...Autoimmune hepatitis(AIH)is a liver disease of unknown cause characterized by hypergammaglobulinemia,typical or compatible liver histology,the absence of viral hepatitis and the production of autoantibodies.Anti-smooth muscle antibodies(SMAs)detected with indirect immunofluorescence(IIF)in rodent tissues are not disease specific,whereas antibodies directed to the filamentous form of actin(F-actin)are specifically involved in AIH-1.As solid-phase immunoassays(SPAs)specifically targeting F-actin,such as enzyme-linked immunosorbent assay(ELISA),have already been included in recent guidelines,in this study,we evaluated the diagnostic per-formance of an immunoblotting SPA for F-actin.We selected 86 samples positive for SMA by IIF(titre≥1:40)and/or for anti-F-actin by ELISA(≥20 units);the patients were divided into 3 groups:AIH-1(n=14),other liver disorders(n=38)and other nonliver-related conditions(n=34).The samples were tested with an immunoblot SPA(European Autoimmune Liver Diseases 9 Ag plus F-actin,Euroimmun,Germany);the qualitative results were converted into numeric intensity values via EurolineScan software.Immunoblotting revealed 16 positive samples(19%),and ELISA revealed 24(28%);among them,7/16(44%)and 11/24(46%)had AIH-1.The diagnostic performance metrics were as follows:sensitivity(50%);specificity(87.5%);positive predictive value(PPV),43.8%;negative predictive value(NPV),90%;and accuracy(81.4%)and equal to those of ELISA.The mean values were greater in the AIH-1 group;the receiver operating characteristic curve(ROC)had an area under curve(AUC)of 0.77 and was not different from that of the ELISA(0.82);the agreement was 81.4%,with a Cohens kappa of 0.49.Immunoblotting might be a reliable assay for the identification of anti-F-actin antibodies,and given its high specificity,its implementation in a clinical laboratory might confirm the specific diagnosis of AIH-1 in patients with IIF-detected SMA.展开更多
文摘Autoimmune hepatitis(AIH)is a liver disease of unknown cause characterized by hypergammaglobulinemia,typical or compatible liver histology,the absence of viral hepatitis and the production of autoantibodies.Anti-smooth muscle antibodies(SMAs)detected with indirect immunofluorescence(IIF)in rodent tissues are not disease specific,whereas antibodies directed to the filamentous form of actin(F-actin)are specifically involved in AIH-1.As solid-phase immunoassays(SPAs)specifically targeting F-actin,such as enzyme-linked immunosorbent assay(ELISA),have already been included in recent guidelines,in this study,we evaluated the diagnostic per-formance of an immunoblotting SPA for F-actin.We selected 86 samples positive for SMA by IIF(titre≥1:40)and/or for anti-F-actin by ELISA(≥20 units);the patients were divided into 3 groups:AIH-1(n=14),other liver disorders(n=38)and other nonliver-related conditions(n=34).The samples were tested with an immunoblot SPA(European Autoimmune Liver Diseases 9 Ag plus F-actin,Euroimmun,Germany);the qualitative results were converted into numeric intensity values via EurolineScan software.Immunoblotting revealed 16 positive samples(19%),and ELISA revealed 24(28%);among them,7/16(44%)and 11/24(46%)had AIH-1.The diagnostic performance metrics were as follows:sensitivity(50%);specificity(87.5%);positive predictive value(PPV),43.8%;negative predictive value(NPV),90%;and accuracy(81.4%)and equal to those of ELISA.The mean values were greater in the AIH-1 group;the receiver operating characteristic curve(ROC)had an area under curve(AUC)of 0.77 and was not different from that of the ELISA(0.82);the agreement was 81.4%,with a Cohens kappa of 0.49.Immunoblotting might be a reliable assay for the identification of anti-F-actin antibodies,and given its high specificity,its implementation in a clinical laboratory might confirm the specific diagnosis of AIH-1 in patients with IIF-detected SMA.
