慢性无症状乙型肝炎病毒携带——感染的持续和低落

CHRONIC ASYMPTOMATIC HBV CARRIAGE: PERSISTENCE AND SUBSIDENCE OF THE INFECTION

按感染状态和肝组织学将慢性无症状HBV携带者261例分为三组,可能代表自然史的三个阶段。初期肝细胞膜HLA-I表达微弱,难以引起T细胞充分的细胞毒效应以清除病毒,免疫耐受容忍稳定的高复制状态。在自发活动期,坏死-炎症较轻微,HBeAg血清转换缓慢,临床过程平静。后期有低水平的免疫清除,在HBsAg清除的8例中有5例肝内仍残留HBV DNA。

To elucidate the natural history of chronic asymptomatic HBV carriers (AsC), liver biopsy was done in 261 cases and all specimens were pathologically examined.They were divided into three groups based on the infection status and liver histology, representing three phases of natural courses of the infection. Initially, class I HLA expression on hepatocyte membrane was too weak to induce a sufficient effect of cytotoxic T cells to clear the infection. The immune tolerance permitted a stable hyperinfec-tion. Even spontaneously activated, the necroinflammatory processes were still weak that the mean his-tologic activity scores were 7.0±3.8 in a system with 18 as full mark. The HBeAg seroconversion was a slow event and usually clinically silent. When the infection subsided, the irnmune clearance was also at low level and in five of eight cases with serum HBsAg cleared up, HBV DNA still remained in the liver. Therefore, AsC has a fluctuate but weak immune response throughout a very long course.