Cyclosporine in the therapy of steroid-resistant idiopathic nephrotic syndrome.

Steroid-resistant nephrotic syndrome with either minimal changes or focal and segmental glomerular sclerosis on initial biopsy is a severe condition as more than 50% of patients with the disease progress to end-stage renal failure within 10 years. We recently identified a distinct form of idiopathic nephrotic syndrome with an autosomal recessive mode of inheritance and were able to map the gene on the long arm of chromosome 1. The absence of recurrence of the disease after renal transplantation suggest a primary defect in a glomerular basement membrane protein. Several reports suggest that cyclosporine is effective in a proportion of patients with steroid-resistant idiopathic nephrotic syndrome, particularly when used in combination with corticosteroids. There are also data suggesting that high doses of cyclosporine may be necessary in patients with severe hypercholesterolemia. However, cyclosporine treatment should be carefully monitored in view of the high risk of nephrotoxicity, as shown by the results of repeat renal biopsies. The beneficial role of cyclosporine in recurrent steroid-resistant nephrotic syndrome is still debated. Preliminary observations suggest that the early use of intravenous cyclosporine may be effective in these patients.