Effect of cyclosporine therapy on idiopathic membranous nephropathy presented with refractory nephrotic syndrome

Background. Recent studies suggested the possible benefits of cyclosporine (CsA) therapy in patients with membranous nephropathy, although most of these studies were short-term. An uncontrolled retrospective study was undertaken to evaluate the long-term effect of CsA therapy on idiopathic membranous nephropathy presented with refractory nephrotic syndrome. Methods. The subjects were eight patients with idiopathic membranous nephropathy presenting with refractory nephrotic syndrome. All patients had received a course of corticosteroid therapy before CsA therapy, and had not responded to the corticosteroid, including one or two administrations of intravenous methylprednisolone pulse therapy. The CsA doses were adjusted to maintain trough blood level at 100 ng/ml during the first 3 months and then reduced to maintain the level at 50 ng/ml in patients who had responded to partial remission. Results. CsA therapy induced a marked decrease in proteinuria from the first month, and a significant decrease from month 3 and thereafter. The mean serum total protein and albumin levels rose, and total cholesterol fell significantly with CsA therapy. The serum creatinine level was unchanged during CsA therapy. Three patients showed complete remission and two were in partial remission, while three were nephrotic at 12 months of CsA therapy. From 18 to 24 months of CsA therapy, three patients were in complete remission, four were in partial remission, and one patient was nephrotic. There were no side effects of CsA, except for gum hyperplasia and hypertrichosis in one patient. Conclusion. These results suggest that long- term CsA therapy at a low or moderate dose is potentially effective and safe in most nephrotic patients with idiopathic membranous nephropathy refractory to corticosteroid therapy.