慢性乙型肝炎患者外周血细胞毒T细胞表面NK相关受体的表达

Expressions of natural killer-associated receptors on cytotoxic T lymphocyte from peripheral blood of patients with chronic hepatitis B

目的探讨慢性乙型肝炎(CHB)患者细胞毒T细胞(CTL)表面NK相关受体(NKR)的变化格局,了解CHB患者CTL对乙型肝炎病毒(HBV)免疫应答的受体途径。方法用流式细胞术分析40例CHB患者(HBV DNA阳性18例,HBV DNA阴性22例)和20名健康对照者(正常对照组)外周血CTL百分率及其表面NK相关的激活性受体NKG2D和NKp30以及抑制性受体NKG2A和KIR2DL3的表达水平,统计分析2组间上述指标的差异及其与HBV DNA载量、HBV感染血清标志物和肝脏损伤标志物等的相关性。结果 CHB组外周血T细胞中CTL百分率[(19.33±6.25)%]显著低于正常对照组[(23.94±6.09)%](P<0.05),CTL表面表达KIR2DL3的细胞比例[(3.32±2.63)%]显著高于正常对照组[(1.55±0.53)%](P<0.05)。CHB患者中HBV DNA阳性组外周血CTL百分率[(16.94±4.8)%]显著低于HBV DNA阴性组[(21.29±6.7)%](P<0.05);HBV DNA阳性组CTL表面表达KIR2DL3的细胞比例[(3.85±3.41)%]显著高于HBV DNA阴性组[(2.91±1.81)%](P<0.05)。相关性分析结果显示,CHB患者外周血中表达NKG2A的CTL比例与血清HBV DNA和丙氨酸氨基转移酶(ALT)水平呈显著正相关(r值分别为0.580、0.671,P<0.01),CHB患者外周血中表达KIR2DL3的CTL比例与HBe Ag呈显著正相关(r=0.556,P<0.001)。结论 CHB患者存在CTL数量和功能的缺失,即T细胞耗竭;CHB患者CTL上NK相关抑制性和激活性受体表达格局的变化致使CTL活性受损和免疫应答紊乱,导致HBV不能得到有效清除,引起肝细胞损伤。CTL上NK相关抑制性受体表达水平可望成为CHB病情评估的新指标以及CHB治疗的潜在新靶点。

Objective To investigate the change patterns of natural killer(NK)-associated receptors(NKR) on cytotoxic T lymphocyte(CTL)from peripheral blood of patients with chronic hepatitis B(CHB),and to study the receptor pathway of CTL from CHB patients responding to hepatitis B virus(HBV). Methods The percentages of CTL and the expressions of NK-associated activating receptors(NKG2D and NKp30) and NK-associated inhibitory receptors(NKG2A and KIR2DL3) on CTL were determined by flow cytometry in 40 patients with CHB(18 cases of HBV DNA positive and 22 cases of HBV DNA negative) and 20 healthy controls.The difference between the 2 groups and the correlations with HBV DNA load,HBV infection serology markers and liver injury markers and so on were analyzed. Results The percentage of CTL in T cells from peripheral blood in CHB group [(19.33±6.25)%] was lower than that of healthy control group[(23.94±6.09)%](P<0.05). The proportion of CTL expressing KIR2DL3 in CHB group [(3.32±2.63)%] was higher than that in healthy control group [(1.55±0.53)%](P<0.05). The percentage of CTL in HBV DNA positive CHB group [(16.94±4.8)%] was lower than that in HBV DNA negative CHB group[(21.29±6.7)%](P<0.05),and the proportion of CTL expressing KIR2DL3 in HBV DNA positive CHB group[(3.85±3.41)%] was higher than that in HBV DNA negative CHB group[(2.91±1.81)%](P<0.05). The proportion of CTL expressing NKG2A was positively correlated with HBV DNA load and alanine aminotransferase(ALT) level in CHB group (r=0.580 and 0.671,P<0.01),and the proportion of CTL expressing KIR2DL3 was positively correlated with hepatitis B e antigen(HBeAg)(r=0.556,P<0.001). Conclusions There is a defect in quantity and function of CTL in CHB patients,which means T cell exhaustion. The change pattern of NK-associated inhibitory receptors and activating receptors on CTL from CHB patients impairs the activation of CTL and immune response disorders,which results that HBV can not be effectively cleared,and hepatic cells are injured. The expression levels of NK-associated inhibitory receptors on CTL are expected to develop into a new indicator to evaluate the disease severity and the potential targets of therapy for CHB.