Hepatitis C virus genotype analysis in patients with type II mixed cryoglobulinemia.

Objective: To investigate the possible role of HCV variants in the pathogenesis of mixed cryoglobulinemia.
Setting: Medical service (rheumatology and hepatology units) of urban, university-affiliated teaching hospitals.
Design: Analysis of viral genotypes in a cohort of patients with hepatitis C virus (HCV) infection and mixed cryoglobulinemia.
Patients: 90 unselected HCV-positive (anti-HCV antibody-positive and HCV RNA-positive) patients consecutively recruited at routine ambulatory visits: 29 with and 61 without (control group) mixed cryoglobulinemia.
Measurements: Clinical and histologic data; HCV RNA detection in serum and peripheral blood mononuclear cells by polymerase chain reaction (PCR); HCV genotype determination by two methods based on genotype-specific primer PCR and genotype-specific probe hybridization, respectively.
Results: Persistent aminotransferase increases were found in 55% of patients with mixed cryoglobulinemia. Peripheral blood mononuclear cells were infected in 80% of cases. In serum samples, HCV genotype 2a/III was detected with a higher prevalence in patients with mixed cryoglobulinemia than in controls (41% compared with 15%). The overall prevalence of genotype 2a/III in mixed cryoglobulinemia increased to 52% when findings in peripheral blood mononuclear cells were also considered. Among patients with mixed cryoglobulinemia, this genotype was more frequent in those without clinical and biochemical signs of liver disease (85%) or with serum autoantibodies (75%).
Conclusions: Mixed cryoglobulinemia may be related, at least in part, to the HCV genotype infecting the host.