Proliferative Glomerulonephritis With Monoclonal IgG1κ Deposits in a Hepatitis C Virus-Positive Patient

Hepatitis C virus infection is associated with several glomerular diseases, most commonly cryoglobulinemic glomerulonephritis, which is typically secondary to type II mixed cryoglobulinemia. We present a patient with hepatitis C virus infection and cryoglobulinemic glomerulonephritis secondary to type I (monoclonal) cryoglobulinemia that is likely related to a concurrent hepatitis C virus infection-associated lymphoproliferative disorder. We list the differential diagnosis of cryoglobulinemic glomerulonephritis. Additionally, the case draws attention to the possibility that, rarely, even clinically undetectable “occult” B-cell lymphoproliferative disorders may result in significant kidney disease.