Renal disease in cryoglobulinemia type II: response to therapy. A case report and review of the literature.

A case of cryoglobulinemia type II with membranoproliferative glomerulonephritis and vasculitis is described. Clinically and serologically the patient responded to cyclophosphamide and prednisone therapy. This correlated with improvement in the glomerular and interstitial lesions on renal biopsy specimens, although skin and renal vasculitis persisted over a 2-year period. These observations suggest important differences in the immunopathologic mechanisms involved in the vascular versus glomerular injury. Infiltration of macrophages were demonstrated in the glomerular capillary lumen while polymorphonuclear cells predominated in the vascular lesion. The presence of macrophages in the glomerular capillary lumen correlated with clinical proteinuria. A review of the literature also suggests that cyclophosphamide in combination with prednisone appears to be an effective therapeutic regimen for the glomerulonephritis of cryoglobulinemia. However, the correlation of clinical response and renal morphology in cryoglobulinemia has heretofore not been emphasized.