HBV感染患者外周血T细胞PD-1基因表达水平的变化与意义

目的:分析HBV感染不同阶段患者外周血T淋巴细胞中PD-1(program death factor-1)分子的基因定量表达情况,探讨PD-1表达水平与血清学指标的相关性。方法:采集并筛选HLA-A2阳性的31例慢性乙型肝炎(CHB)患者、9例急性恢复期乙型肝炎患者(AHB)、15例乙肝相关性肝硬化患者(LC)和10例健康献血者的外周血,实时荧光定量PCR分析总T细胞内PD-1的mRNA水平,同时测定其配体PD-L1、PD-L2在外周血单个核细胞(PBMCs)中的表达量;酶联免疫吸附试验(ELISA)检测HBV血清标记物水平,荧光定量PCR检测血清HBV DNA载量,同时进行肝功能检测。结果:以各基因在正常对照组的定量表达水平为基础值,HBeAg阳性CHB组T细胞内PD-1和PBMCs内PD-L1的mRNA表达水平明显升高,与HBeAg阴性CHB组和AHB组比较均有显著性差异,但与LC组比较无统计学意义(P>0.05)。外周血PBMCs内PD-L2的mRNA水平在各实验组中无明显差异(P均>0.05)。在所有检测的CHB患者中,外周血T细胞内PD-1表达水平在高病毒载量组(HBV DNA≥107拷贝/ml)明显高于低病毒载量组(HBV DNA<107拷贝/ml)和正常对照组,且与血清HBV病毒载量成正相关(r=0.41,P<0.01),但与血清ALT水平无明显相关性。结论:外周血T细胞中PD-1基因水平在慢性乙型肝炎患者组,尤其是在HBeAg阳性组和高病毒载量组明显上调,提示T细胞高表达的PD-1可能通过与其配体PD-L1作用而抑制T细胞免疫应答,并导致病毒持续感染。

PD-1 expression in peripheral T cells of patients with HBV infection and its significance

Objective: To analyze the expression levels of PD-1(program death factor-1)in peripheral T cells from patients infected with HBV,and to investigate its relationship with HBV serological markers.Methods: A total of 65 HLA-A2 subjects,including 31 patients with chronic hepatitis B(CHB),9 with acute resolved hepatitis B(AHB),15 with HBV related liver cirrhosis(LC) and 10 healthy blood donators,were enrolled.The expression of PD-1 in peripheral T cells and PD-1 ligands PD-L1 and PD-L2 in PBMCs were determined by relative quantitative real-time PCR.The serum HBV markers,HBV DNA load and liver function were also measured.Results: Taken the PD-1 and PD-ligands expression in normal controls as a baseline level,the expression of PD-1 and PD-L1 from CHB patients was significantly increased,while the expression of PD-L2 was relatively low in all groups.In CHB patients,the PD-1 expression in peripheral T cells from patients with high viral load was much higher than that from those with low viral load or from normal controls.And the PD-1 expression level positively correlated with serum HBV DNA load(r=0.41,P<0.01) but not with serum ALT level.Conclusion: Long-term exposure to HBV antigens in CHB patients may increase the expression of PD-1 in T cells and thus leads to the virus persistent infection.