Simultaneous occurrence of hepatitis C virus-associated glomerulonephritis and AL amyloidosis.

We report a 65-year-old male with hepatitis C virus (HCV)-associated glomerulonephritis (GN) and AL amyloidosis. This patient had a 14-year history of HCV infection with positive serum HCV RNA at presentation. Diagnosis of HCV-related GN was established using immunohistochemistry in which the HCV-NS3 antigen was mainly detected as granular deposition in glomerular mesangium. AL amyloidosis was determined by electron microscopy, positive Congo red staining and identification of lambda-chain in the kidney specimen and monoclonal IgG-lambda in serum and urine. Under immunoelectron microscopy, the HCV-NS3 antigen was found in electron-dense deposits, while lambda-chains appeared in the amyloid-like filaments.