Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
Gastroenterology. 2010 Jan;138(1):315-24. doi: 10.1053/j.gastro.2009.09.017. Epub 2009 Sep 24.
BACKGROUND & AIMS: We followed patients with ongoing hepatitis C virus (HCV) exposure following control of an initial HCV infection to determine whether primary control conferred protection against future persistent infections.
Twenty-two active injection drug users (IDU) who had cleared a primary hepatitis C viremia for at least 60 days were monitored monthly. Reinfection was defined as the detection of a new HCV infection. Protection was assessed based on the magnitude and duration of viremia following reinfection and generation of T-cell and neutralizing antibody (nAb) responses.
Reinfection occurred in 11 IDU (50%) who previously spontaneously controlled primary HCV infection. Although viral clearance occurs in approximately 25% of patients with primary infections, spontaneous viral clearance was observed in 83% of reinfected patients. The duration and maximum level of viremia during subsequent episodes of reinfection were significantly decreased compared with those of the primary infection in the same subjects. In contrast to chronic infection, reinfection was associated with a significant increase in the breadth of T-cell responses. During acute infection, nAbs against heterologous viral pseudoparticles were detected in 60% of reinfected subjects; cross-reactive nAbs are rarely detected in patients who progress to chronic infection.
HCV reinfection is associated with a reduction in the magnitude and duration of viremia (compared with the initial infection), broadened cellular immune responses, and generation of cross-reactive humoral responses. These findings are consistent with development of adaptive immunity that is not sterilizing but protects against chronic disease.
我们对初始 HCV 感染得到控制后持续存在 HCV 暴露的患者进行随访，以确定初次控制是否能预防未来持续性感染。
22 例急性注射吸毒者（IDU）在清除 HCV 血症至少 60 天后，每月接受监测。再感染定义为新 HCV 感染的检测。保护作用基于再感染后病毒血症的幅度和持续时间以及 T 细胞和中和抗体（nAb）反应的产生来评估。
11 例（50%）先前自发性控制原发性 HCV 感染的 IDU 发生再感染。尽管原发性感染中约有 25%的患者会清除病毒，但在再感染患者中，83%的患者出现自发性病毒清除。与同一受试者的原发性感染相比，随后再感染期间的病毒血症持续时间和最大水平明显降低。与慢性感染不同，再感染与 T 细胞反应范围的显著增加相关。在急性感染期间，60%的再感染受试者中检测到针对异源病毒假型的 nAb；在进展为慢性感染的患者中很少检测到交叉反应性 nAb。
HCV 再感染与病毒血症幅度和持续时间降低（与初始感染相比）、细胞免疫反应范围扩大以及交叉反应性体液反应的产生相关。这些发现与适应性免疫的发展一致，这种免疫不是灭菌性的，但能预防慢性疾病。
