Clinicopathological analysis of allogeneic hematopoietic stem cell transplantation-related membranous glomerulonephritis

SummaryAllogeneic hematopoietic stem cell transplantation (HSCT)-related membranous glomerulonephritis (MGN) is poorly understood. A total of 830 patients who underwent HSCT at Toranomon Hospital from 2000 to 2012 were evaluated retrospectively, including 621 patients receiving umbilical cord blood transplantation (UCBT) and 208 patients receiving unrelated bone marrow transplantation. MGN was diagnosed in 5 patients after UCBT (versus none after bone marrow transplantation) and occurred concomitantly with chronic graft-versus-host disease after cessation of immunosuppression. Light microscopy did not show any definite spikes or bubbling of the glomerular basement membrane (GBM) in all 5 patients. In 1 patient (case 5), endocapillary proliferative lesions with fibrin-like deposits were noted in addition to MGN findings. Immunofluorescence demonstrated granular deposits of immunoglobulin G (IgG; IgG1 and IgG4) along the GBM with negativity for C3, C4, and C1q in 4 patients (cases 1-4), whereas case 5 showed positivity for IgG (IgG1, IgG2, IgG3, and IgG4) as well as for C3, C4, and C1q. Electron microscopy revealed electron-dense deposits in the subepithelial space of the GBM in cases 1-4. In case 5, electron-dense deposits were present in the mesangium and the subendothelial space of the GBM, as well as in the subepithelial space. After treatment with immunosuppressants (prednisolone and/or cyclosporin) or angiotensin-converting enzyme inhibitors, complete remission with disappearance of proteinuria was achieved 12.2 months in all 5 patients, but nephrotic-range proteinuria relapsed in 2 patients during follow-up. Serum anti-PLA2R autoantibody was negative in 3 patients. HSCT-related MGN only occurred after UCBT. We believe that there were 2 morphologic patterns: early MGN and membranoproliferative pattern glomerulonephritis.