ABSTRACT
Proliferative glomerulonephritis with monoclonal IgG deposits is a novel disease entity characterized by (1) glomerular monoclonal IgG deposits restricted to a single IgG subclass and a single light chain isotype, associated with proliferative GN; (2) granular deposits by EM; (3) no clinical and laboratory evidence of cryglobulinemia. A 47-year-old male presented with edema and muscle cramps. Urinalysis revealed protein 3+ and 5-9 RBC's/HPF. BUN/Cr were 25/1.7 mg/dL, 24 hour urine protein 5.4 g/day, and CCr 56.3 mL/min/1.73m2. Cryglobulin was negative. The histologic findings of the renal biopsy showed mesangial cell proliferation with double contour of GBM on LM, diffuse finely granular electron-dense deposit in subendothelial & mesangial area with no amyloid fibril on EM, and strong immune reactivity to IgG and kappa light chain along the glomerular basement membrane on IF. Serum and urine protein EP, IEP and immunofixation EP showed no evidence of monoclonal gammopathy. Bone marrow aspiration & biopsy were negative for plasma cell infiltration. The patient is on supportive management with an AII blocking agent.