Treatment of de novo and recurrent membranous nephropathy in renal transplant patients.

Membranous nephropathy (MN) is one of the common glomerular diseases diagnosed in transplanted kidneys. The exact impact of posttransplantation MN on the risk for graft loss and long-term graft outcome is not defined clearly. In recent reports, it has emerged as the third most frequent glomerulonephritis (de novo or recurrent) associated with renal allograft loss. Most cases of posttransplantation MN are thought to be idiopathic but cases associated with established secondary causes also have been reported. Patients can present with varying degrees of proteinuria and graft dysfunction. Risk factors that predict a poor outcome are not well established and unlike MN in the native kidneys, spontaneous remission is rare. Patients should be evaluated carefully for complications associated with nephrotic syndrome or graft dysfunction and managed accordingly. The beneficial effects of steroids, cyclosporine, mycophenolate mofetil, cyclophosphamide, chlorambucil, or other agents have not been validated. The role of specific treatments in cases of secondary MN is uncertain. Retransplantation is a reasonable option for patients who develop graft failure secondary to MN.