Evans Alexander, Riva Antonio, Cooksley Helen, Phillips Sandra, Puranik Smrithi, Nathwani Amit, Brett Sara, Chokshi Shilpa, Naoumov Nikolai V
Institute of Hepatology, University College London, London, United Kingdom.
Hepatology. 2008 Sep;48(3):759-69. doi: 10.1002/hep.22419.
Hyperexpression of the programmed death 1 (PD-1) molecule is a hallmark of exhausted T-cells, having a negative impact on T-cell activation and function. We studied longitudinally 18 hepatitis B e antigen (HBeAg)-positive patients undergoing treatment with direct antivirals (telbivudine or lamivudine) to determine the relationship between treatment-induced viremia reduction and HBeAg seroconversion with respect to PD-1 levels and T-cell reactivity. PD-1 expression was assessed by (1) flow cytometry and (2) quantitative real-time polymerase chain reaction; hepatitis B virus (HBV)-specific CD8+ T-cells were quantitated by pentamer staining; T-cell reactivity to HBV antigens was determined by interferon gamma (IFNgamma) and interleukin 10 (IL-10) enzyme-linked immunosorbent spot (ELISPOT) assays; and central/effector memory phenotypes were defined by phenotypic markers. PD-1 expression correlated closely with viremia levels. On therapy, PD-1 decreased significantly on total CD8+ T-cells, HBV-specific CD8+ T-cells, and CD3+/CD8- T-cells both as the percentage of positive cells (P < 0.01) and as the mean fluorescent intensity (P < 0.05), and this was paralleled by a marked reduction of PD-1 messenger RNA levels (P = 0.001). HBeAg serocoversion (in 6/18 patients) resulted in a further PD-1 decrease with a 50% reduction in the frequency of PD-1+/CD8+ T-cells, which was not observed in patients remaining HBeAg-positive. The decrease in PD-1 expression was associated with increased frequencies of IFNgamma-producing T-cells and decreased frequencies of IL-10 producing T-cells. At baseline, PD-1 expression correlated directly with the frequency of hepatitis B core antigen (HBcAg) central and effector memory phenotypes, whereas an inverse correlation was observed between PD-1 expression and HBcAg-specific effector phenotypes.
These results demonstrate that in chronic HBV infection, both viremia levels and HBeAg drive PD-1 expression and resulting T-cell impairment. Treatment-induced suppression of HBV replication reduces PD-1 expression; however, additional immunotherapeutic interventions are needed for restoration of T-cell functions.
程序性死亡1（PD-1）分子的过表达是耗竭性T细胞的一个标志，对T细胞的激活和功能有负面影响。我们对18例接受直接抗病毒药物（替比夫定或拉米夫定）治疗的乙肝e抗原（HBeAg）阳性患者进行了纵向研究，以确定治疗诱导的病毒血症降低和HBeAg血清学转换与PD-1水平和T细胞反应性之间的关系。通过（1）流式细胞术和（2）定量实时聚合酶链反应评估PD-1表达；通过五聚体染色对乙肝病毒（HBV）特异性CD8+T细胞进行定量；通过干扰素γ（IFNγ）和白细胞介素10（IL-10）酶联免疫斑点（ELISPOT）试验确定T细胞对HBV抗原的反应性；并通过表型标志物定义中枢/效应记忆表型。PD-1表达与病毒血症水平密切相关。在治疗过程中，总CD8+T细胞、HBV特异性CD8+T细胞和CD3+/CD8-T细胞上的PD-1均显著下降，无论是阳性细胞百分比（P<0.01）还是平均荧光强度（P<0.05），同时PD-1信使RNA水平也显著降低（P = 0.001）。HBeAg血清学转换（18例患者中的6例）导致PD-1进一步下降，PD-1+/CD8+T细胞频率降低50%，而HBeAg仍为阳性的患者未观察到这种情况。PD-1表达的降低与产生IFNγ的T细胞频率增加和产生IL-10的T细胞频率降低有关。在基线时，PD-1表达与乙肝核心抗原（HBcAg）中枢和效应记忆表型的频率直接相关，而在PD-1表达与HBcAg特异性效应表型之间观察到负相关。
这些结果表明，在慢性HBV感染中，病毒血症水平和HBeAg均驱动PD-1表达及由此导致的T细胞损伤。治疗诱导的HBV复制抑制降低了PD-1表达；然而，需要额外的免疫治疗干预来恢复T细胞功能。
