Hepatitis C virus infection and mixed cryoglobulinemia: a striking association.
The high frequency of liver involvement in cryoglobulinemia is well established. Although both etiology and pathogenesis have remained so far undefined, recent studies suggest an association of mixed cryoglobulinemia with hepatitis C virus infection. To explore this hypothesis further, we assessed the prevalence of hepatitis C virus antibodies and RNA in a large group of patients, including: (1) 35 patients with cryoglobulinemia without clinical evidence of liver involvement (group 1), (2) 15 patients with symptomatic cryoglobulinemia associated with chronic liver disease (group 2) and (3) 12 patients with asymptomatic cryoglobulinemia associated with chronic liver disease (group 3). Anti-hepatitis C virus antibodies were detected by a second-generation enzyme-linked immunosorbent assay and third-generation immunoblot (SIA Prototype RIBA), whereas the polymerase chain reaction was used for the detection of viral RNA. Anti-hepatitis C virus antibodies, as detected by enzyme-linked immunosorbent assay, were demonstrated in 21 (60%) patients from group 1, 11 (73.3%) from group 2 and 10 (83.3%) from group 3. The immunoblot identified as positive 3 further patients in group 1 (giving a prevalence of 68.6%) and all patients in groups 2 and 3. Hepatitis C virus RNA was demonstrated in cryoprecipitates from 21 of 24 immunoblot-positives and from 6 of 11 immunoblot-negatives, indicating an actual active viral replication in 77.1% of group 1. This was also found in 13 (86.7%) and 10 (83.3%) cryoprecipitates of groups 2 and 3, respectively. Type II cryoglobulinemia was the prevalent form in group 1 (88.6%) and group 2 (73.3%), whereas type III was found in group 3 (58.3%) and in 26.7% of group 2.(ABSTRACT TRUNCATED AT 250 WORDS)