Rapidly progressive glomerulonephritis and monoclonal gammopathy

A case of rapidly progressive glomerulonephritis associated with nephrotic syndrome, hematuria, and edema is reported. Monoclonal IgG-lambda was found in the serum and urine. Renal biopsy revealed diffuse proliferative glomerulonephritis with crescent formation. Immunofluorescent study revealed IgG and lambda in a focal segmental distribution. Subepithelial humps were found on electron microscopic examination. A spectacular feature of the deposits was the presence of organized linear fibrils within the humps. Similar fibrils were found in the mesangium and urinary space. Renal function deteriorated rapidly, necessitating hemodialysis in eight months. In addition to the present case, 24 cases of glomerulonephritis associated with "benign" monoclonal gammopathy reported since 1970 are reviewed, and the potential causal relationship between monoclonal gammopathy and glomerular involvement is stressed.