慢性乙型肝炎患者HBsAg“a”决定簇变异与HBV基因型的相关性

目的探讨HBeAg阳性的慢性乙型肝炎患者HBsAg＂a＂决定簇氨基酸（AA）变异与HBV基因型的相关性。方法对99例HBeAg阳性的慢性乙型肝炎患者进行HBVS基因直接测序,分析HBV基因型及HBsAg＂a＂决定簇的AA变异,并应用Logistic回归分析其相关性。结果 B基因型占52.5%（52/99）,C基因型占47.5%（47/99）,未发现其他基因型;HBsAgAA126Thr存在变异,而AA124、131、133、139、141、145未发现变异及AA122～124未发现缺失或插入,其中AA126Thr占52.5%（52/99）,Ile占39.4%（39/99）,Ser占4.0%（4/99）,Ala占4.0%（4/99）;AA126Thr变异为Ile在C基因型中多见（χ2=35.201,P〈0.001,OR=48.125）。结论 HBeAg阳性的慢性乙型肝炎患者HB-sAg＂a＂决定簇AA变异多发生在AA126Thr变异为Ile,且基因型C较基因型B更易发生AA126Ile变异。

Relationship between mutations within HBsAg "a" determinant and HBV genotypes in chronic hepatitis B patients

Objective To study the relationship between mutations within HBsAg ＂a＂ determinant and HBV genotypes in HBeAg-positive chronic hepatitis B （CHB） patients. Methods All 99 HBeAg-posi- tive CHB patients were recruited for research. HBV genotypes and mutations within HBsAg ＂a＂ determinant were assayed by sequencing HBV S gene, and then Logistic regression was used to identify their correlation. Results HBV genotypes in all patients were B and C, 52.5 % （52/99） and 47.5% （47/99）, respectively, and other genotypes were not found. There were mutations at amino acid position of 126 in HBsAg ＂a＂ deter-minant,but not at amino acid position of 124,131,133,139,141 or 145. Also there were no deletions or insertions at amino acid position from 122 to 124. At amino acid position of 126 in all patients, threonine were 52.5% （52/99）, isoleneine were 39.4% （39/99） , serine were 4.0% （4/99） and alanine were 4.0% （4/99）. Furthermore, the substitutions of threonine to isoleucine were found more often in genotype C than B （ X^2 = 35. 201 ,P 〈 0. 001, OR = 48. 125）. Conclusions The mutations in HBsAg ＂a＂ determinant are found more often at amino acid position of 126, where threonine can be substituted to isoleucine more often than serine and alanine. Furthermore, the substitutions of threonine to isoleucine are found more often in genotype C than B.