Successful treatment of anti-glomerular basement membrane antibody disease combined with membranous nephropathy using rituximab: a case report

Anti‑glomerular basement membrane (anti‑GBM) disease is a rare autoimmune disorder that classically manifests as rapidly progressive glomerulonephritis and pulmonary hemorrhage. The coexistence of anti-GBM disease and membranous nephropathy (MN) was first reported in 1976. Although such cases are rare, many reported patients develop progressive kidney injury and poor renal outcomes. We report a young man with sequential-onset dual glomerulopathy. He initially presented with MN alone and achieved partial remission following glucocorticoid and cyclosporine therapy. Three years later, he developed rapidly progressive glomerulonephritis, and kidney biopsy confirmed anti-GBM disease superimposed on pre-existing MN. This sequential pattern differs from the simultaneous onset of both lesions reported in many previous cases. To minimize gonadal toxicity, he received individualized therapy consisting of glucocorticoids, dose-adjusted cyclophosphamide, rituximab, and plasma exchange. He ultimately recovered normal kidney function and had a favorable renal outcome. This case expands the clinical spectrum of overlapping anti-GBM disease and MN and suggests that patients with MN in remission require long-term serial monitoring for early detection of superimposed autoimmune kidney injury. Individualized immunosuppressive strategies tailored to each patient’s clinical characteristics are essential to optimize kidney outcomes in such complex glomerular diseases.