Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
Critical Care Medicine Department, NIH Clinical Center, Bethesda, MD, 20892, USA.
Sci Rep. 2018 Oct 17;8(1):15296. doi: 10.1038/s41598-018-33719-x.
Spontaneous or treatment induced seroconversion in chronic HBV infection is rare and generation of anti-HBs antibodies is the current goal of HBV therapeutics. Here we investigated B and follicular T helper (Tfh) cell defects that persist in HBV infection despite long-term nucleos(t)ide analog (NUC) treatment and possible mechanisms behind them. RNA sequencing revealed that patient B cells have upregulated expression of multiple inhibitory receptors including members of FcRL family and downregulation of genes involved in antigen presentation. An expansion of atypical memory CD19CD10CD27CD21 subset of B cells, that express high levels of FcRL5, is persistently present in patients. HBs antigen specific IgG response is concentrated in classical memory and not in atypical memory subset, confirming dysfunction of this subset. Activated Tfh, which expressed excessive CD40L upon polyclonal stimulation, were present in patients. Incubation of B cells from healthy individuals with HBV core (HBc) or CD40L resulted in induction of inhibitory receptors FcRL4, FcRL5 and PD-1 on CD19+ cells and resulted in altered B cell phenotypes. Mechanistically, HBc binds B cells and causes proliferation specifically of FcRL5+ B cell subset. Our results provide evidence that HBV directly causes upregulation of inhibitory pathways in B cells resulting in an accumulation of atypical B cells that lack anti-HBs function.
在慢性乙型肝炎病毒(HBV)感染中,自发性或治疗诱导的血清转换很少见,产生抗-HBs 抗体是目前 HBV 治疗的目标。在这里,我们研究了尽管长期使用核苷(酸)类似物(NUC)治疗,但仍持续存在的 B 细胞和滤泡辅助性 T 细胞(Tfh)缺陷及其潜在机制。RNA 测序显示,患者 B 细胞上调表达多种抑制性受体,包括 FcRL 家族成员,下调参与抗原呈递的基因。异常记忆 CD19CD10CD27CD21 B 细胞亚群的扩增在患者中持续存在,该亚群表达高水平的 FcRL5。HBs 抗原特异性 IgG 反应集中在经典记忆 B 细胞亚群中,而不在异常记忆 B 细胞亚群中,证实了该亚群的功能障碍。在多克隆刺激下,表达过量 CD40L 的活化 Tfh 细胞存在于患者中。用 HBV 核心(HBc)或 CD40L 孵育健康个体的 B 细胞可导致 CD19+细胞上诱导性抑制性受体 FcRL4、FcRL5 和 PD-1 的表达,并导致 B 细胞表型改变。从机制上讲,HBc 结合 B 细胞并特异性地引起 FcRL5+B 细胞亚群的增殖。我们的研究结果提供了证据,表明 HBV 直接导致 B 细胞中抑制性途径的上调,导致缺乏抗-HBs 功能的异常 B 细胞的积累。