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Glomerular Basement Membrane Antibody

Anti-GBM antibody disease is caused by autoantibody mediated injury to the glomerular basement membrane of the kidney and the alveolar basement membrane of the lungs. Anti-GBM antibody disease is most often idiopathic, but sometimes occurs after pulmonary infection or injury. The development of anti-GBM antibodies may precede the onset of clinical signs and symptoms by many months. Anti-GBM disease is rare, with an estimated prevalence of less than 1 case per million persons per year, This disease exhibits a bimodal distribution. Younger adults between the ages of 20 and 40 years are more commonly men and typically present with both pulmonary and renal disease whereas patients who are 60 years of age and older are more often women with isolated renal disease.

Anti-GBM presents as acute renal failure with a urinalysis showing proteinuria, dysmorphic red cells, white cells and red cell and granular casts. Renal biopsies show rapidly progressive cresentic glomerulonephritis. Thirty to sixty percent of patients also have alveolar hemorrhage at presentation.

The principal target for the anti-GBM antibodies is the noncollagenous domain 1(NC1) of the alpha-3 chain of type IV collagen, which is highly expressed in the glomerular and alveolar basement membranes. Patients with and without alveolar hemorrhage have the same autoantibody. Alveolar hemorrhage is more likely in patients in whom the alpha-3 chain antigen is exposed due to previous pulmonary injury such as smoking, infection, cocaine inhalation, or hydrocarbon exposure. Autoreactive T cells may also contribute to the development of glomerular and alveolar injury. There is some evidence of a genetic association with HLA-DR2.

The diagnosis of anti-GBM antibody disease requires demonstration of anti-GBM autoantibodies either in the serum or a kidney biopsy. Serum autoantibodies are detected using a multiplex immunoassay in which polystyrene microspheres are coated with human alpha-3(IV) antigens (Bio-Plex 2200 Vasculitis, Bio-Rad Laboratories). Anti-GBM antibody in patient serum is detected by phycoerythrin (PE)-conjugated antihuman-IgG antibody

Up to one third of patients with rapidly progressive glomerulonephritis have coexistent anti-neutrophil cytoplasmic antibody (ANCA), which is usually myeloperoxidase antibody. Approximately 5% of patients who initially test positive for ANCA have anti-GBM antibodies. This combination is referred to as double antibody positive disease. Patients with double antibody–positive disease exhibit hybrid features of both anti-GBM disease and ANCA-associated vasculitis.

Reference range is a negative result. Positive results are consistent with anti-GBM antibody disease.

Specimen requirement is one red top or SST tube of blood.

References

Hellmark T and Segelmark M. Diagnosis and management of Goodpasture’s disease (anti-GBM). J Autoimmun 2014;48-49:108-112.

Gulati K and McAddoo SP. Anti-glomerular basement membrane disease. Rheum Dis Clin North Am 2018;44:651-73.

Smith C. et al. Double Trouble. New Engl J Med 2019;381:1854-60.

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