Clinical Analysis of Late-Onset Nephrotic Syndrome after Allogenic Hematopoietic Stem Cell Transplantation.

Objective: To investigate the morbidity, pathology, pathogenesis and treatment of late-onset nephrotic syndrome (NS) after allogenic hematopoietic stem cell transplantation (allo-HSCT).

Methods: Late-onset NS was investigated in 167 patients with hematopoietic malignancies who survived more than 3 months after allo-HSCT from February 2001 to August 2006. Kidney biopsy and detection of serum levels of immunoglobulin (Ig), autoantibody, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) were performed in patients with late-onset NS. Pathology of kidney was studied by light microscopy, immunofluorescence and transmission electron microscopy. Associations between the onset of NS with conditioning regimens, human leucocyte antigen (HLA) matching, chronic graft versus host disease (cGVHD) and cytomegalovirus infection were analyzed. Statistical analysis was performed with SPSS/PC version 13.0.

Results: Five patients were identified as late-onset NS after allo-HSCT in167 allo-HSCT patients, including 4 patients with membranous glomerulonephritis (MGN) and 1 patient with minimal change disease (MCD). The immunofluorescence of glomerular lesions revealed that the Ig of immune complex deposition were IgG in 3 patients, IgM in 1 patient and IgG/IgM double-positive in 1 patient. Electron-dense deposit can be found on epithelium and basement membrane under the transmission electron microscope. Serum levels of IFN-γ and TNF-α were markedly increased in NS patients as compared with patients without NS. Serum antinuclear antibody was positive in 2 patients and serum IgG and IgM were in high level in 2 patients, respectively. Glucocorticoid combined with cyclophosphamide (CTX) was fundamentally effective in treatment for late-onset NS. One patient got complete response, 3 got partial response and 1 was stable after the treatment. The associations of the onset of late-onset NS post-HSCT with conditioning regiments, HLA-matching, cGVHD and CMV infection had no statistical significance.

Conclusions: Glomerular histology of late-onset NS after allo-HSCT was comprised mainly of MGN and secondary MCD. The pathogenesis of late-onset NS may be related to the abnormality of humoral immunity. Glucocorticoid combined with CTX was a fundamentally effective treatment.