Membranoproliferative glomerulonephritis associated with hepatitis C virus infection.

The hepatitis C virus genome has been recently sequenced and cloned, allowing the identification of patients exposed to this virus, which is now felt to be the principal cause of "non-A, non-B" hepatitis. The hepatitis B virus has long been implicated in the pathogenesis of several glomerulopathies including membranoproliferative glomerulonephritis, mixed cryoglobulinemia, and membranous glomerulonephritis. Several authors have recently reported an association between hepatitis C virus infection and glomerular disease. The case of a patient with chronic hepatitis C virus infection who developed the nephrotic syndrome 3 months after liver transplantation is described. Serologic testing was significant for an elevated rheumatoid factor, circulating cryoglobulins, and a mildly depressed C4 level. Hepatitis C virus antibody and viral RNA (by polymerase chain reaction) were present in both the serum and cryoglobulin fraction. A renal biopsy demonstrated membranoproliferative glomerulonephritis. It is believed that persistent infection with the hepatitis C virus is responsible for an immune complex-mediated glomerulonephritis in this patient. Because hepatitis C has now been pathogenetically linked to several glomerulopathies, testing for this virus should be considered in the serologic work-up of the patient with glomerulonephritis.