PCR-RFLP检测HBeAg阴性preS1抗原阳性的HBV感染者前C区基因变异

Detection of HBV pre-C mutation in patients with positive pre-S1 antigen and negative HBeAg

目的探讨HBeAg阴性的HBV感染者前S1（preS1）抗原阳性与前C区基因G1896A变异发生频率的关系。方法用荧光定量PCR检测64例HBeAg阴性HBV感染者血清HBVDNA，ELISA法检测preS1抗原，以错配聚合酶链反应结合限制性片段长度多态性（PCR—RFLP）分析HBV前C区1896位点的基因变异。结果64例血清中preS1抗原阳性25例（39．1％），preS1抗原阴性39例（60．9％）；25例preS1阳性的标本中23例（92．0％）HBVDNA阳性（19例≥10^3copies／ml，4例为10^2copies／ml，2例为检测限以下），有21例（84．0％）发生1896位点变异；39例preS1抗原阴性的标本中11例（28．2％）HBVDNA为10^2～10^3 copies／ml、17例（43．6％）发生1896位点变异。preS1阳性与阴性患者1896位点变异率有显著性差异（P〈0．005）。结论HBeAg阴性的HBV感染者中，preS1抗原不受前C区基因变异的影响，可以更客观地反映HBV复制状态。

Objective To investigate the relationship between HBV pre-C gene G1896A mutation and positive pre S1 in the patients with negative HBeAg. Methods HBV DNA was assayed in serum of 64 patients with negative HBeAg by quantitative polymerase chain reaction （PCR） ,and pre-S1 antigen was detected by ELISA. The point mutation of pre-C 1896-position was detected by PCR and restriction fragment length polymorphism （PCR-RFLP）. Results Positive pre S1 antigen was found in 25 samples of 64 samples with 39.1% of positive rate. Among the 25 samples with positive pre S1 antigen 23 （92.0%） were found to be HBV DNA positive （HBV DNA ≥ 103 copies/ml in 19 samples and ≥ 102 copies/ml in 4 samples）. In the other 39 samples preS1 antigen was negative with 60.9% of negative rate. and 11 of them was found to be HBV DNA positive（ ≥5 × 10^2copies/ml）. In the 25 samples with positive pre S1 antigen 21 were 1896-point mutation with mutation rate of 84.0% while in 39 samples with negative pre-S1 antigen 17 were 1896-point mutation and the mutation rate was 43.6%. Comparing the mutation rate of the samples with positive and negative pre-S1 antigen a significant difference was found （ P 〈 0. 005 ）. Conclusions For the HBV-infected patients with negative HBeAg, preS1 antigen is a better marker to reflect replication of HBV than HBeAg.