HBsAg和HBsAb同时阳性慢性HBV感染者血清病毒PreS/S区基因序列分析及临床意义探讨

Detection of PreS/S gene sequences in chronic HBV infections with concurrent HBsAg and HBsAb and discussing the clinical significance

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 HBV-DNA between two groups（P0.05）.As to the distribution of genotype,two goups had similar results（P0.05）.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,P0.05）.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.