HBsAg、抗HBs共存与HBV基因型及基因变异的关系

目的探讨无锡地区HBV感染者HBsAg与抗HBs共存模式与基因型、S基因变异、病毒复制的关系.方法采用微粒子捕获酶联放射免疫法及ELISA测定HBV M;套式PCR扩增HBV DNA,并作序列分析;荧光定量法检测HBV DNA含量.结果抗HBs阳性血清加入多价HBsAg后,抗HBs可阴转;21份血清出现S区多位点变异,造成HBsAg肽36、47、63、77、89、90、115、126、129、139、154位氨基酸替换,该变异不影响病毒复制;本模式中B基因型1例(3.2%),C基因型30例(96.8%),没有发现A、D、E、F、G基因型;基因变异与否和基因型无显著性差异,P＞0.05.结论S基因变异可改变HBsAg抗原性,导致HBsAg与抗HBs结合力降低,以及检测灵敏度的提高,这些是造成HB-sAg与抗HBs共存的原因;本模式以C基因型占绝对优势,且基因型与基因变异无相关性.

Relation of HBV genotype/S gene mutation to concurrent HBsAb and HBsAg

Objective To study the relation of HBV genotype/S gene mutation to concurrent HBsAb and HBsAg. Methods The serological markers of HBV were detected by ELISA or microparticle enzyme immunoassay(Abbolt).Quanti- tative analysis of HBV DNA was performed by PCR and S gene fragments were directly sequenced.Results All samples posi- tive for anti-HBs became negative after reacting with HBsAg-positive serum.The multi-site mutation in S gene resulting in ami- no acid substitution at the sites of 36,47,63,77,89,90,115,126,139 and 154 was identified in the samples from 21 pa- tients.However,the mutation did not affect viral replication.Genotype B was found in 1 case and genotype C in 30 cases. Genotypes A,D,E,F,G and H were not found in this group of patients.S gene mutation was not significantly related to the genotype of HBV(P>0.05).Conclusions The reasons for concurrent HBsAb and HBsAg are improvement of testing sensi- tivity and change in HBsAg antigenicity due to S gene mutation resulting in reduction of binding capacity of HBsAg to HBsAb. Genotype C is predominant in this group of patients and there is no relationship between genotype and gene mutation.