[Efficiency of rituximab treatment for recurrence of membranous glomerulopathy after renal transplantation].

Idiopathic membranous glomerulonephritis (MGN) is a rare cause of end-stage renal failure, which can lead to chronic hemodialysis. This glomerulopathy can recur after renal transplantation despite immunosuppressive therapy. To date, there is no confirmed therapy for treatment of renal grafts after recurrence of MGN. Herein, we report on a 27-year-old man who underwent cadaveric renal transplantation for MGN in September 2001. At 2 months posttransplant, a renal biopsy showed membranous deposition on immunofluorescence staining evocative of recurrence of MGN. Proteinuria developed progressively and, at one year, was estimated at 7.65 g/24 h, with hypoalbuminemia of 24 g/l. This persisted despite symptomatic treatment with anti-proteinuric agents (enalapril 20 mg/day and irbesartan 75 mg/day) and atorvastatin (10 mg/day). By March 2004, his proteinuria was 11 g/day; therefore, therapy with rituximab (monoclonal anti-CD20) at 375 mg/m(2) weekly was initiated for four consecutive weeks, followed by the same dosage every four months for one year. Biological controls performed two weeks after the fourth infusion of rituximab showed a fall in proteinuria, assessed at 1 g/24 h, with albuminemia of 29 g/l and normalized lipidic results. A renal biopsy performed 6 months after the first infusion was unchanged. Follow-up at 30 months showed consistent remission of membranous nephropathy, demonstrated by a serum creatinine level of 150 mumol/L, microalbuminuria of 107 mg/24 h and normal albuminemia of 43.7 g/l. There were no side effects; in particular, no infectious complications occurred, despite CD19 lymphocytes being still negative after 30 months. Monoclonal CD-20 antibodies have shown efficacy against MGN compared to conventional therapies in native kidneys. It has recently been shown that CD20 mRNA is overexpressed in the renal interstitium in patients suffering from MGN and that the interstitial infiltrates is mainly composed of B-cell lymphocytes in these patients. These data may explain the efficiency of rituximab in these circumstances.