Retrospective demographic and serological analysis of patients who overcame HCV infection spontaneously and those who develop chronic hepatitis

Worldwide, an estimated 170 million people have been infected with hepatitis C virus (HCV). While most individuals develop a persistent infection, a smaller proportion of individuals is able to spontaneously eradicate the virus. The mechanisms determining the outcome of infection are poorly understood. To find demographic and/or clinical correlates to spontaneous viral clearance, a group of individuals positive for anti-HCV antibodies but repeatedly negative for HCV-RNA (without therapy), who were identified between 1992 and 2000 (n=67), was compared to a group of consecutive out-patients with chronic hepatitis C (n=62). Demographic and clinical findings were recorded. Sera were tested for humoral response to HCV and other viruses. Sera from chronic hepatitis C patients were tested for viral genotype; sera from patients with self-limited infections were tested for type-specific antibodies to virus genotypes. Cases and controls were matched by age and sex. Patients with a self-limited HCV infection were found to be significantly younger than those with a chronic infection and the proportion of males was higher. Moreover, patients who recovered from HCV infection had significant lower levels of serum AST and ALT activity than those with a chronic infection. The source of infection was also found to be significantly different between patients with self-limited and persistent infections, i.e. the majority of individuals with a self-limited HCV infection had a history of intravenous drug abuse (79% versus 41%). The number of patients with HCV genotype 3 infection / serotype 3 was higher among those with spontaneous clearance than among chronic hepatitis C patients. No difference was found between the groups regarding the number of individuals with markers of HAV and/or HBV immunity, although the group of individuals with self-limited HCV infections contains a significant number of patients with acute HAV or HBV infections (19/61 versus 0/61). In conclusion, our findings suggest that HCV elimination is facilitated in intravenous drug abusing individuals.