Introduction:

Hematopoietic stem cell transplantation (HSCT) is a treatment for hematopoietic malignancies and certain immune disorders. Although rare, nephrotic syndrome is a significant complication of HSCT, often linked to graft-versus-host disease (GvHD) and frequently manifesting as membranous nephropathy. This case aims to highlight the rare detection of PLA2R antibodies in a patient with nephrotic syndrome following HSCT.

Case presentation:

A 52-year-old man with acute myeloid leukemia underwent allogeneic HSCT. Six months after discontinuation of immunosuppressants, he experienced two episodes of GvHD, requiring further immunosuppressive therapy. One year later, he presented with lower limb edema and anorexia. Investigations revealed nephrotic-range proteinuria (24-h urine protein 13 g; urine ACR 7004 mg/g), severe hypoalbuminemia (1.97 g/dL), and hyperlipidemia. Complement levels (C3, C4) were normal. Renal biopsy demonstrated membranous nephropathy with positive anti-PLA2R staining. Treatment with corticosteroids and rituximab was initiated. The patient subsequently achieved complete remission.

Literature review:

A Review of 11 reported cases (mean age 53.4 years; 8 (72.7%) allogeneic, 3 (27.3%) autologous) showed membranous nephropathy as the predominant pathology (9, 81.8%), followed by minimal change disease and focal segmental glomerulosclerosis (1, 9.1% each). IgG and/or C3 deposition occurred in 9 (81.8%). GvHD was present in 7 (63.6%). Treatment commonly included corticosteroids and immunosuppressants, including rituximab. Clinical improvement occurred in all cases, with complete or partial remission in 9 (81.8%).

Conclusion:

This case highlights the rare occurrence of nephrotic syndrome post-HSCT. The detection of anti-PLA2R antibody positivity on tissue immunofluorescence of the renal biopsy suggests a complex immune mechanism potentially overlapping with primary membranous nephropathy pathways. Corticosteroids and rituximab proved effective, reinforcing their role in management.