乙型肝炎病毒“a”决定簇的变异对HBsAg定量的影响

Influence of "a" determinant variation of hepatitis B virus on HBsAg quantification

目的为了明确乙型肝炎病毒"a"决定簇的变异对乙肝表面抗原(hepatitis B virus surface antigen,HBsAg)定量的影响。方法收集广州血液中心无偿献血者的乙肝HBsAg阳性血清标本,共41例;采用时间分辨免疫荧光法对乙肝HBsAg进行定量,根据HBsAg定量结果将标本分为两组:低HBsAg组(0.05~100 IU/mL)和高HBsAg组(>100 IU/mL);提取乙型肝炎病毒DNA,采用高灵敏度巢式PCR扩增病毒DNA的S区,对S区"a"决定簇氨基酸序列进行比对。结果 41例乙肝HBsAg阳性标本中,以B基因型为主,占75.6%;C基因型占24.4%;对HBV病毒S区"a"决定簇氨基酸置换位点和置换率进行分析,没有发现低HBsAg组(0.05~100 IU/mL)和高HBsAg组(>100 IU/mL)存在特异性的氨基酸置换位点。低HBsAg组与高HBsAg组S区中"a"决定簇的氨基酸置换率相比差异无统计学意义(P>0.05)。结论乙肝病毒"a"决定簇的变异并不是影响HBsAg定量的主要因素。

Objective To investigate the influence of ＂a＂ determinant variation of hepatitis B virus on hepatitis B virussurface antigen（HBsAg） quantification. Methods A total of 41 HBsAg（＋） serum samples were collected from blood donors atthe Guangzhou Blood Center. HBsAg was quantified by time resolved immunofluorescence. According to the HBsAgquantitative results, the samples were divided into two groups： a low HBsAg group（0.05-100 IU/mL） and high HBsAg group（〉100 IU/mL）. The S region of the extracted virus DNA was amplified by using the high sensitivity nested PCR, and the ＂a＂ determinant amino acid sequences were compared between the two groups. Results Among the 41 HBsAg positive samples,the B genotype was the main genotype, accounting for 75.6%, and C genotype accounted for 24.4%. In the amino acidsubstitution rate of ＂a＂ determinant, there was no statistically significant difference between the low HBsAg group and highHBsAg group（P〉0.05）, and no specific replacement site was found in the two groups. Conclusion The amino acidsubstitution of ＂a＂ determinant of hepatitis B virus is not the main factor influencing the quantification of HBsAg.