Immune complexed (IC) hepatitis C virus (HCV) in chronically and acutely HCV-infected patients.

In infected individuals, hepatitis C virus (HCV) exists in various forms of circulating particles which role in virus persistence and in HCV resistance to IFN therapy is still debated. Here, the proportion of HCV bound to immunoglobulin was determined in plasma of 107 chronically infected patients harbouring different HCV genotypes and, for comparison, of six patients with acute HCV infection. The results showed that, in spite of wide individual variability, chronically HCV-infected patients exhibited an extremely high proportion of immune complexed (IC) virus regardless of plasma HCV load and infecting genotype. Moreover, no significant association was found between baseline proportion of IC HCV and response to IFN treatment. Plasma samples collected within 2 weeks of treatment from 20 patients revealed a significant decline of mean IC HCV values relative to baseline that clearly paralleled the decay of total HCV load. In acutely infected patients, circulating HCV was not IC or IC at very low levels only in patients developing chronic HCV infection. Collectively, these findings strengthen the possibility that IC virus could play a critical role in the pathogenesis of HCV infection.