Obinutuzumab in Crescentic Anti-Glomerular Basement Membrane Disease with Linear IgG Deposition: A Case Report.

Introduction: Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune vasculitis that often leads to rapidly progressive glomerulonephritis and poor renal prognosis. Standard treatment typically involves plasmapheresis, corticosteroids, and cyclophosphamide. However, the therapeutic role of obinutuzumab, a B-cell-depleting monoclonal antibody, remains under-explored in anti-GBM disease. Case Presentation: We report a 20-year-old male with isolated renal anti-GBM disease following a dental infection, who presented with severe acute kidney injury (creatinine >700 μmol/L), high anti-GBM antibody titers, and crescentic glomerulonephritis on biopsy. Despite initial therapy with plasmapheresis, corticosteroids, and cyclophosphamide, renal function deteriorated. Obinutuzumab (500 mg IV) was administered as adjunct therapy, leading to rapid antibody clearance within 1 month. Remarkably, the patient achieved partial renal recovery and was dialysis-independent by 3 months, with stable stage 3 chronic kidney disease at 5-month follow-up. Conclusion: This case underscores the potential role of obinutuzumab as an innovative adjunctive therapy in severe anti-GBM disease, even in patients with traditionally poor prognostic markers. Early and aggressive multimodal treatment, including B-cell targeting, may improve outcomes in selected cases.