Anti-Glomerular Basement Membrane Antibody Disease: Clinicopathologic Profile and Outcomes.

Background: Anti-glomerular basement membrane antibody disease is a rare autoimmune disease caused by antibodies to α3 chain of type 4 collagen. Patients presenting with severe renal involvement requiring dialysis have poor response to treatment. Materials and Methods: We conducted a retrospective and prospective study at Institute of Nephrology, Madras Medical College, Chennai, India by analyzing the data of patients with biopsy-proven anti-GBM antibody disease treated from January 2013 to December 2019. Results: There were 2,949 kidney biopsies in the study period and 92 showed crescentic glomerulonephritis (GN). Of those, 20 patients (10 males) had anti-GBM antibody disease. Mean age was 40.75 ± 14.75 years. Rapidly progressive renal failure was the most common mode of presentation (95%); five (25%) patients had diffuse alveolar hemorrhage (DAH) and nineteen patients (95%) required dialysis at presentation. Seven patients (35%) were positive for anti-neutrophil cytoplasmic antibody (anti-myeloperoxidase in six and anti-proteinase 3 in one). Of the twelve patients (60%) who received immunosuppression (cyclophosphamide, steroids, and plasma exchange), two patients (10%) attained remission, and two patients (10%) expired due to sepsis. Crescentic GN was the predominant pathology in kidney biopsy in 19 patients (95%). Mesangial hypercellularity with deposition of IgA and C3 in mesangium was present in one patient. Conclusion: In our study, anti-GBM antibody disease accounted for 21.7% of crescentic GN. Majority of patients presented late, requiring dialysis. Patient survival was 90%, while renal survival was only 10%. One patient had co-occurrence of IgA nephropathy with anti-GBM antibody disease.