Hepatic lymphoid aggregates in chronic hepatitis C and mixed cryoglobulinemia.

We have examined the clinical (virological and immunological), histological and immunohistochemical features of liver lymphoid nodules in hepatitis C virus-positive (HCV+)/mixed cryoglobulinemia (type II and III) and chronic hepatitis C. The clinical features of liver disease were found to be similar in all patients. In all these groups, liver lymphoid nodules were observed to a similar extent, being more frequent in earlier phases of liver disease and less in more advanced stages. These data were confirmed by studies in serial biopsy samples taken from individual patients with type II mixed cryoglobulinemia; the loss of lymphoid nodules with progression to more advanced histological stages of disease in these patients was accompanied by a decrease of the serum levels of cryoglobulins (although not statistically significant). By immunohistochemical analysis, the liver lymphoid nodules contained predominantly B cells with a CD5+/bcl2+/Ki67- phenotype, which were always polyclonal in type III mixed cryoglobulinemia and chronic hepatitis C, and monoclonal in type II mixed cryoglobulinemia. These immunological features were consistent with an active role of the immune system in HCV-associated liver necro-inflammation. Only in type II mixed cryoglobulinemia was there a clonal restriction of B cells. The immunological profile (autoantibodies) and viral genotypes were examined in some patients, but no significant correlation with clinical and immunohistochemical findings was found; however, the prevalence of genotype 2a was significantly higher in type II mixed cryoglobulinemia than in type III and chronic hepatitis without cryoglobulinemia.