IgG heavy-chain deposition disease

A 51-yr-old man presented with renal failure, proteinuria, hematuria, and hypertension. The serum contained two monoclonal protein spikes, an IgG4 lambda and free lambda light chains. Free gamma heavy chains were absent from serum. A bone marrow biopsy did not show evidence of a plasmalymphocytic dyscrasia. Renal biopsy showed a nodular glomerulopathy with linear deposits of gamma 4 heavy chains alone along glomerular, tubular, and vascular basement membranes and in mesangial regions. No light chains were detected in the kidney despite staining with antisera directed against both free and bound light chains and the F(ab')2 fragment of IgG. The term heavy-chain deposition disease is appropriate in view of the above features.