Cryoglobulin characteristics in
chronic hepatitis C (CHC) might be of importance for knowing more about the pathogenesis and treatment of the disease. We aimed to investigate the relationship between
cryoglobulin types and their specificity against hepatitis C virus (HCV) antigenic
epitopes in CHC patients. We analyzed samples from 43 patients with HCV-associated
cryoglobulinemia, of whom 4 had concomitant
lymphoma.
Cryoglobulins were measured, purified, typed by immunofixation electrophoresis, and tested for
IgG and
IgM anti-HCV antibodies by immunoblot analysis and an
enzyme-linked
immunosorbent assay (ELISA). Clinical and other laboratory data were recorded. The median cryocrit level of the tested samples was 6%. Type I
cryoglobulins were detected in 9.3% (4/43) of the cryoprecipitates, and type II
cryoglobulins were detected in 48.8% (21/43) of the cryoprecipitates.
IgM monoclonal
protein, mainly
IgM(κ), was found in 92% (23/25) of type I and II cryoprecipitates. Type III
cryoglobulins were identified in 41.9% (18/43) of the patients and were associated with high blood serum
IgG levels. In 81.3% (13/16) of type II and 92.3% (12/13) of type III
cryoglobulins, there was
IgG reactivity against the viral core region. Ninety-two percent and 32% of
IgG anti-HCV core-positive cryoprecipitates had additional specificities against the NS3 and NS4 regions, respectively. Also,
IgM anti-HCV antibodies were detected in 31% of the cryoprecipitates. In conclusion, all types of
cryoglobulins were found in patients with HCV-associated
cryoglobulinemia, with type II being the most frequently identified. Type III
cryoglobulins were common and were associated with high serum
IgG levels. HCV-related
cryoglobulins demonstrated
IgM, and particularly
IgG, anti-HCV specificities, mainly against the core and NS3
epitopes.