慢性乙型肝炎病毒感染者程序性死亡因子1基因拷贝数和mRNA的表达水平

Study on the copy numbers and mRNA expression levels of the programmed death-1 gene in chronic hepatitis B patients

目的研究慢性HBV感染者程序性死亡因子1（PD-1）基因的拷贝数和mRNA表达水平，以及在不同临床表现患者间的差异。方法实时荧光定量PCR法检测健康对照者27例（对照组）、慢性HBV携带者31例（携带组）、慢性重型肝炎患者19例（重肝组）、乙型肝炎相关性原发性肝癌患者29例（肝癌组）的外周血单个核细胞PD-1基因拷贝数及其mRNA的表达水平，分析各组间PD-1基因拷贝数及其mRNA水平表达的差异，以及PD-1基因拷贝数与其mRNA表达水平的关系。两组间率比较用Chi-square检验，多个样本间比较用秩和检验，多个样本间PD-1mRNA表达水平的两两比较用秩变换分析。结果106份样本中，PD-1基因拷贝数变异范围为0～3拷贝，单拷贝率在对照组、携带组、重肝组和肝癌组分别为37．o％、35．5％、26．3％和6．9％；2拷贝率分别为55．6％、58．毗、63．20／0和82．8％；3拷贝率分别3．7％、6．5％、10．5％、10．3％。将2～3拷贝合并，称为多倍体，多倍体率在对照组、携带组、重肝组和肝癌组分别为59．3％、64．5％、73．7％、93．1％，4组间PD-1基因多倍体率比较，x^2=9.583，P〈0.05，差异有统计学意义。与肝癌组比较，对照组和携带组多倍体率更低，X^2值分别为8．985、7．215，P值均〈0．05，差异有统计学意义。对照组、携带组、重肝组、肝癌组PD-1平均基因拷贝数分别为1．59士0．63、1．70±0．52、1．84±0．60、2．00±0．37。对照组、携带组、重肝组、肝癌组PD-1mRNA表达水平中位数分别为0．00254、0．00272、0．00255、0．00133。携带组、重肝组、肝癌组PD-1基因拷贝均数呈逐步上升趋势，而PD-1mRNA表达则呈下降趋势。3组慢性HBV感染者中，肝癌组、重肝组、携带组2个拷贝数个体的PD-1mRNA表达所对应的平均秩分别为19．59、32．57、33．22，肝癌组平均秩低于重肝组和携带组，F=5．395，P值均〈0．05，差异有统计学意义。结论（1）慢性HBV感染者PD-1基因拷贝数及其mRNA表达在不同临床表现的人群中的分布存在差异；（2）PD-1基因多拷贝的慢性HBV携带者值得长期随访。

Objective To study the copy numbers and mRNA expression levels of the Programmed Death-1 gene in chronic hepatitis B patients and to analyze the differences of the copy numbers and mRNA expression levels of the gene in patients with different clinical outcomes. Methods Real time PCR was adopted to detect the PD-1 gene copy numbers and their mRNA expressions in peripheral blood mononuclear cells （PBMCs） from 27 samples from healthy donors in Control group, 31 samples from chronic asymptomatic HBV carriers （ASC, n=31）, 19 samples from chronic severe hepatitis B patients （CSH, n=19） and 29 samples from Primary hepatitis B Virus-related hepatocarcinoma （PHC, n=29）. The differences and relationship of copy numbers and their mRNA expression levels among those groups were compared and analyzed by adopting Chi-square test and Rank sum test. Results PD-1 gene copy number deviated from 0 copy to 3 copies among all the 106 samples. In control group, ASC group, CSH group and PHC group, the percentages of cases of haploid （single） were 37.0%, 35.5%, 26.3% and 6.9%, respectively, the percentages of cases of diploid （double） were 55.5%, 58.0%, 63.2% and 82.8%, respectively, and the percentages of cases of triploid （triple） were 3.7%, 6.5%, 10.5% and 10.3%, respectively. The percentage of cases of polyploid （diploid and triploid） in control goup, ASC group, CSH group and PHC group were 59.3%, 64.5%, 73.7% and 93.1%, respectively. The different distribution of PD-1 gene copy number of polyploid was significant in total samples （x^2 = 9.583, P 〈 0.05）. Compared with Control Group and ASC group, the percentage of cases ofpolyploid in PHC group was lower with the x^2 equals to 8.985 and 7.215 respectively and both withP 〈 0.05. The difference between the two groups was statistically significant. The mean PD-1 gene copy numbers for these four groups were 1.59 ± 0.63, 1.70 ± 0.52, 1.84 ±0.60 and 2.00 ± 0.37 while the median were 0.002 54, 0.002 72, 0.002 55 and 0.001 33 respectively. Except the control group, there was a uptrend in the other three groups while PD-1 gene mRNA expression presented a downtrend. The mean of PD-1 gene copy numbers of 2 and their mRNA expression levels were 19.59, 32.57 and 33.22 for PHC, CSH and ASC groups among which PHC group had the lowest value, there was significant differences found in the comparison with F = 5.395 andP 〈 0.05. Conclusion PD-1 gene copy numbers and their mRNA expression levels were different in chronic HBV infected patients with different transformation. It is valuable to follow up the patients with more than 1 copy number ofPD-1 gene in long term.