摘要
目的 分析拉米夫定耐药HBV毒株部分RT区序列 ,以了解RT区YMDD基序之外HBV的变异情况。方法 采用PCR方法对拉米夫定临床耐药患者治疗前及耐药后血清HBV部分RT区序列进行扩增 ,扩增的核苷酸片段覆盖HBVRT的B区～E区及S基因“a”决定簇 ,对PCR产物进行直接测序 ,将HBVRT区核苷酸和推导的氨基酸序列与治疗前 5 0株HBV野毒株序列和Genebank中 77株不同基因型野毒株序列进行比较 ,同时对HBV进行血清分型。结果 60例患者有YMDD变异 ,其中 2 6例为adw亚型 ,占 43 .3 3 % ;3 4例为adr亚型 ,占 5 6.67%。另外 12例患者( 16.67% )未发现YMDD变异。 16例患者出现 11个RT保守区氨基酸变异 (不包括 5 5 0和 5 2 6位氨基酸变异 ) ;2 5例患者出现 19个HBVRT非保守区氨基酸变异。结论 拉米夫定耐药株的氨基酸变异不仅见于RTB区的 5 2 6和C区 5 5 0两个位点 ,B、C区的其他位点、保守区以及RT非保守区也可发生多个变异。
Objective To analyze the partial RT region sequences of lamivudine resistant HBV strains from patients with chronic hepatitis B and to evaluate the amino acid variances outside HBV YMDD motif. Methods 72 patients with chronic hepatitis B treated by lamivudine for over 1 year were included in the study. All the patients had breakthrough of serum HBV DNA levels and ALT flare up and were clinically diagnosed as being lamivudine resistant. Partial RT region sequences of lamivudine resistant HBV strains and pretreatment HBV wild strains were amplified by PCR using specific primers flanking B C regions of RT and “a” determinant of S gene. Nucleotide and predictive amino acid sequences were compared with wild type HBV sequences from pretreatment serum samples and Genebank. Results YMDD mutations occurred in 60 patients with chronic hepatitis B, 26(43.33%) with serotype adw, 34(56.67%) with serotype adr, the rest of the patients (16.67%) had no YMDD mutation. 11 amino acid variances in conserved regions of RT other than variances at amino acid position 550 and 526 were found in 16 patients. An additional 19 amino acid variances in non conserved regions of RT were also detected in 25 patients.Conclusion Lamivudine resistant HBV strains may harbor several amino acid variances, not only in the non conserved regions of RT, but also in the conserved regions outside YMDD motif.
出处
《肝脏》
2003年第2期28-31,共4页
Chinese Hepatology
