Relapse of subacute anti-glomerular basement membrane nephritis following self-discontinuation of steroid therapy.

Anti-glomerular basement membrane (GBM) nephritis is an autoimmune disease which typically presents rapid progressive glomerulonephritis. A subacute course and relapse are rare. We report the case of a 23-year-old woman with no prior medical history, who was referred for proteinuria and elevated serum creatinine (Cr) level of 3.3 mg/dL. Two weeks later, upon her visit to our hospital, her creatinine level was 3.2 mg/dL. Five months prior, her Cr was 1.2 mg/dL. Urinalysis showed 2.3 g/gCre of proteinuria and microscopic hematuria. The anti-GBM antibody titer was high at 135 U/mL. Anti-neutrophil cytoplasmic antibody and anti-nuclear antibody were negative. Kidney biopsy revealed crescentic glomerulonephritis with advanced glomerular sclerosis and diffuse linear staining of IgG along the GBM. She received corticosteroids, intravenous cyclophosphamide and 7 sessions of plasma-exchanges. After three months, her Cr improved to 1.9 mg/dL and the antibody became undetectable. However, she self-discontinued prednisolone 2 months later. Three weeks after discontinuation, she presented with nausea, oliguria. Her Cr level had risen to 9.6 mg/dL and the anti-GBM antibody titer was 4.0 U/mL. A second kidney biopsy showed progression of glomerulosclerosis, endothelial injury in the arterioles characterized by fibrin deposition, and extensive tubulointerstitial damage. Despite resuming treatment, her kidney function did not recover, and she required maintenance hemodialysis. This case highlights two atypical features of anti-GBM nephritis: subacute progression over 5 months, and relapse after antibody negativity triggered by steroid discontinuation. This emphasizes the importance of adherence to immunosuppressive therapy, even after serological remission.