Severe steroid-responsive nephrosis associated with hypersensitivity.

Sensitivity to cow's whole milk investigated in six patients with the idiopathic nephrotic and an elemental diet was given. After proteinuria had decreased to less than or equal to 500 mg/24 hours on consecutive days patients were challenged with cow's milk. This resulted in the return of significant proteinuria, oedema, and decreased urine volume together with a decrease in serum-IgG concentrations in four patients. Acute alteration of plasma C3 complement component accompanied milk challenge in all 6 patients. There were no consistent alterations in other immunoglobulin concentrations. Intradermal skin testing with cow's milk extract was positive in all patients. These results suggest that in some individuals clinical and biochemical manifestations of the nephrotic syndrome of childhood may be related to hypersensitivity of food products.