[Glomerular lesion in patients with type II mixed cryoglobulinemia having antibodies to hepatitis C virus].

We report here two cases of mixed cryoglobulinemia showing renal involvement associated with hepatitis C virus (HCV) infection. The subjects were 62- and 63-year-old males. Both patients presented with purpura on the legs, which was diagnosed as allergic vasculitis by skin biopsy. Case 1 followed a clinical course of progressive nephrotic syndrome with mild hematuria. He also had diabetes mellitus and hypertension. In contrast, case 2 showed only mild hematuria without proteinuria at the time of the renal biopsy. Both cases had immunological disarrangements, such as severe hypocomplimentemia and seropositive rheumatic factor. Recently, it was reported that patients with type II mixed cryoglobulinemia had HCV seropositivity, and revealed membranoproliferative glomerulonephritis. These facts strongly suggested that renal lesions are the result of direct damage mediated by cryoglobulinemia and an activated complement pathway through an immune complex mechanism related to HCV.