腎移植後に発生した膜性腎症の1例

Abstract

39歳男.1984年にIgA腎症と診断され徐々に悪化し, 1998年に腹膜透析が導入され, 1999年に父親をドナーにABO適合生体腎移植術を施行された.術後3ヵ月目から尿蛋白が徐々に増加し, 2000年にプロトコール生検によりIgG, C3のdopositが見られ, 上皮下にdense depositを認め, de novoに発症した膜性腎症I期と診断された.ATII受容体拮抗剤カンデサルタンを2mmgより投薬開始し, 8mmgまで増量し, 蛋白尿は減少した.2001年の腎生検では尿蛋白は著明に減少しており, 膜性腎症は軽快していると考えられた

A 39-year-old man who had been diagnosed with immunoglobulin A (IgA) nephropathy underwent renal transplant from his father. The operation was performed under cyclosporine, prednisolone and mizoribine treatment. Renal function was stable following transplantation, but proteinuria ranged between 1 g/day and 3 g/day. Protocol biopsy 1 year after transplantation revealed membranous glomerulonephritis, with IgG and C3 deposits under immunofluorescence, and subepithelial deposits detected on electron microscopy. The patient was treated by limiting protein intake, controlling blood pressure and administering candesartan. Proteinuria decreased from 5.6 g/day to 1 g/day, but a graft biopsy was performed 2 years after transplantation because of a slightly increasing creatinine level. There was no sign of rejection, and IgG and C3 deposits observed under immunofluorescence had decreased. After the graft biopsy, the creatinine level was stable and proteinuria decreased to 0.7 g/day. In conclusion, de novo nephropathy such as membranous glomerulonephritis should also be considered a possible cause of proteinuria following renal transplantation.