Glomerulonephritis associated with complete deficiency of the fourth component of complement. Response to intravenous immunoglobulin.

A 15-year-old girl with complete C4 deficiency and a lupus-like disorder developed evidence of nephritis after 4 years of followup. Renal biopsy demonstrated an immune complex glomerulonephritis, with deposits in the capillary loops, the paramesangium, and the mesangial matrix. Renal function was normal. The patient was treated with monthly infusions of intravenous immunoglobulin for 6 months. The treatment was well tolerated, and resulted in resolution of the rash and hematuria. Followup biopsy showed less proliferation and fewer loop deposits. In light of the serious risk of infections that is associated with complement deficiency, approaches to glomerulonephritis that do not include immunosuppression should be considered.