Hepatitis C virus-related mixed cryoglobulinemic endocapillary proliferative glomerulonephritis and B-cell non-Hodgkin lymphoma: a case report and literature review.

OBJECTIVE: Chronic HCV (hepatitis C virus) infection is recognized as the major cause of mixed cryoglobulinemia. Cryoglobulins continually precipitate and form deposits on the vascular endothelium of small to medium-sized blood vessels, which may progress to vasculitic syndrome.

CASE REPORT: A 44-year-old female patient with chronic HCV infection presented with purpuras, edema and proteinuria. Her renal findings included microscopic hematuria, moderate proteinuria and endocapillary proliferative glomerulonephritis (EnPGN) on renal biopsy. Serum cryoglobulins comprised mixed monoclonal cryoglobulins characterized by IgM kappa. The serum protein electrophoresis revealed a monoclonal M protein (9.0%). CD19 and CD20-positive B-cell oligo-monoclonal expansion in the bone marrow was revealed. Rapid relief of the clinical symptoms, the disappearance of proteinuria and a sharp decrease in the HCV viral load were observed in our case after one year of interferon therapy.

CONCLUSIONS: HCV infection-associated extrahepatic manifestations are diverse, which may lead to misdiagnosis. This is the first report of HCV-associated cryoglobulinemic EnPGN and B-NHL, which rapidly responded to interferon.