Abstract
Anti-glomerular basement membrane disease is a rare small-vessel immune-complex vasculitis (incidence <1/1.000000/year), characterized by the presence of serum antibodies directed against glomerular and pulmonary basement membrane antigens. It is characterized by rapidly progressive crescentic glomerulonephritis, active urinary sediment, subnephrotic proteinuria and oligo-anuria, often coupled to alveolar haemorrage. The main renal lesion on histology specimen is the presence of crescents, often associated to fibrinoid necrosis and linear pattern anti-glomerular basement membrane antibodies positivity on direct immunofluorescence. Lung involvement can be determined clinically, radiologically or by bronchoscopy, by isolation of macrophagic hemosiderin deposits. In order to rapidly remove the pathogenetic autoantibody, plasmapheresis is the mainstay of treatment, associated with cyclophosphamide and steroids, both to control the inflammation and reduce antibody production. A deep knowledge of the pathogenetic mechanisms involved in the anti-GBM disease is mandatory to reach a more and more appropriate diagnostic-therapeutic approach: on one hand, new triggers of the disease (SARS-COV2 infection) and new pathogenetic autoantigens (laminin-521, peroxidasin) have been identified; on the other hand, new therapeutic approaches to lower antibody clearance emerged. The monoclonal anti-CD20 antibody Rituximab can be reasonably used in refractory disease with persistence of antibody anti-GBM, or where standard therapy is not suitable. IdeS (Immunoglobulin G degrading enzyme of Streptococcus pyogenes), which cleaves pathogenetic IgG in a specific site, could be used in place of apheresis, if associated with immunosuppressive therapy. New studies are necessary to better understand pathogenesis, etiology, and treatment options. Key words: Anti-GBM, vasculitis, laminin-521, COVID-19, RItuximab, IdeS