Anti Gbm (Good pasture's antibody), in Visit Clinic

Anti‑GBM antibodies are pathogenic IgG autoantibodies (predominantly IgG1 and IgG3) directed against the noncollagenous (NC1) domain of the alpha‑3 chain of type IV collagen in the glomerular basement membrane. They produce linear IgG deposition with complement activation, causing rapidly progressive glomerulonephritis and, when lungs are involved, pulmonary hemorrhage (Goodpasture’s disease).

Anti-GBM disease and Goodpasture’s are closely related but not identical. Anti-GBM refers to autoimmune antibodies targeting the glomerular basement membrane causing rapidly progressive kidney injury. Goodpasture’s (syndrome) describes the clinical picture when anti-GBM disease also causes lung hemorrhage. In practice the terms are often used interchangeably, though Goodpasture’s emphasizes combined kidney and lung involvement.

The classic triad of Goodpasture syndrome comprises: 1) pulmonary hemorrhage causing hemoptysis; 2) rapidly progressive (crescentic) glomerulonephritis with hematuria and acute renal failure; and 3) circulating anti–glomerular basement membrane (anti‑GBM) antibodies with linear IgG deposition along alveolar and glomerular basement membranes on immunofluorescence. It is an autoimmune small‑vessel vasculitis; prompt treatment is critical to prevent irreversible organ damage.

Goodpasture’s disease, caused by anti‑glomerular basement membrane antibodies, is usually ANCA negative. However, roughly 10–30% of patients have concurrent ANCA, most commonly MPO‑ANCA (p‑ANCA). Dual positivity can affect clinical course and management, so clinicians typically test for both anti‑GBM antibodies and ANCA when anti‑GBM disease is suspected.

Goodpasture's kidney disease (anti‑GBM disease) is a rare autoimmune disorder where antibodies attack the glomerular basement membrane, often affecting lungs too. It causes rapidly progressive glomerulonephritis with blood and protein in urine, reduced kidney function, and sometimes pulmonary hemorrhage. Diagnosis uses anti‑GBM antibody testing and kidney biopsy. Treatment is urgent: plasmapheresis and immunosuppression (steroids, cyclophosphamide).

Anti-GBM antibodies target basement membranes primarily in the kidneys and lungs. In the kidneys they bind the glomerular basement membrane, causing rapidly progressive (crescentic) glomerulonephritis and acute kidney injury. In the lungs they bind alveolar basement membranes, causing pulmonary capillaritis and potentially life‑threatening hemorrhage. Rarely other basement membranes may be involved, but kidney and lung involvement is characteristic.