Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposition: Report of Two Cases and Review of Literature

Here we report two cases of proliferative glomerulonephritis with monoclonal IgG deposits, a form of renal involvement by monoclonal gammopathy that mimics immune complex glomerulonephritis. Case 1 presented with incidental proteinuria and a renal biopsy showed mesangioproliferative glomerulonephritis with monoclonal IgG kappa deposits on immunofluorescence examination. He remains stable after one year follow up. Case 2 presented with rapidly progressive renal failure and renal biopsy showed rescentic membranoproliferative glomerulonephritis with monoclonal IgG kappa deposits on immunofluorescence study. He showed no response to aggressive immunosuppressive medication and plasmapheresis and remained anuric. He underwent renal transplantation three months later but disease recurred in the allograft, which was diagnosed on a biopsy one and a half months post-transplant. Extensive work up for underlying paraprotein disease was negative in both patients. Our aim is to expand awareness and highlight the heterogeneity in the clinical presentation, histology and outcome of this rare entity.