Membranoproliferative glomerulonephritis in a patient with congenital deficiency of the third component of complement: effect of treatment with plasma.

A 21-year-old woman with a known congenital complement component 3 (C3) deficiency developed membranoproliferative glomerulonephritis. The kidney biopsy exhibited deposits of immunoglobulins and complement components despite the C3 deficiency. The administration of fresh frozen plasma was without therapeutic benefit. Corticosteroid treatment was followed by an improvement in kidney function.