目的:分析HBsAg和HBsAb同时阳性慢性HBV感染者的血清病毒PreS/S区基因序列,探讨其临床意义.方法:收集HBsAg和HBsAb同时阳性慢性HBV感染者32例,其中HBV DNA阳性者12例(实验组),其余20例为HBV DNA阴性.另外选取HBsAg阳性、HBsAb阴性和HBV DNA阳性的慢性HBV感染者12例(对照组).采用聚合酶链反应(PCR)法体外扩增两组患者HBV PreS/S基因序列并测序分析,比较两组间PreS/S基因变异情况,结合临床资料探讨其临床意义.结果:实验组与对照组在性别、年龄、HBeAg阳性率、HBsAg滴度及HBV DNA水平上差异均无显著性意义(P＞0.05).两组基因型分布亦相似(P＞0.05).实验组与对照组在PreS1区、PreS2区、S区、MHR(主要亲水)区及"a"表位区各区域的核苷酸替换率相当(P＞0.05).实验组中1例患者的PreS区有一长约144bp的片段缺失,位于PreS/S区nt285-428位(PreS1区末端及PreS2区起始部).结论:HBsAg和HBsAb同时阳性的现象与PreS/S区基因突变无明显的相关性,HBsAb的出现对HBsAg和HBsAb同时阳性且HBV DNA亦阳性的患者不具有保护作用.%Objective: To analyze sequences of HBV PreS/S gene in chronic HBV infections with concurrent HBsAg and HBsAb and preliminary discuss the clinical significance of this special serous phenomenon. Methods: Thirty-two patients with chronic HBV infection and HBsAg ( + ) /HBsAb ( + ) were collected, 12 of them had positive HBV DNA ( as experimental group), others had negative HBV DNA. Another 12 patients were HBsAg ( + ) /HBsAb ( - ) and had positive HBV DNA,( as control group) . Polymerase chain reaction (PCR) was used to amplificate the PreS/S gene of two groups then sequencing. Using statistical analysis to detect differences between two groups. With their clinical data, we discussed the clinical significance. Results: There were no significant differences in sex, age, rate of positive HBeAg, levels of HBsAg or copies of HBVDNA between two groups (P ＞ 0.05 ) . As to the distribution of genotype, two gnups had similar results (P ＞ 0. 05 ) . Nucleotide substitution rates between two groups were similar in the following regions: PreS1 region, PreS2 region, S region, MHR region and “a” epitope region (0. 98％ vs 0. 86％, 1.06％ vs 1.11％, 0. 56％ vs 0.49％, 1.27％ vs 1.09％, 1.39％ vs 0. 81％;in all of this region, P ＞ 0.05 ) . One patient in experimental group had large deletion mutations in the PreS region ( nt285～428) . Conclusion: The phenomenon of concurrent HBsAg and HBsAb had no significant association with mutations of PreS/S gene, appearance of HBsAb did not mean protection to them.
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