Proposed mechanism of action for antibodies to LAMP-2 in anti-neutrophil cytoplasmic antibody-associated systemic vasculitis . (a) Antibodies develop to FimH, an antigen found on fimbriated bacteria such as E. coli, develop during an infection. (b) In genetically susceptible individuals, these antibodies cross react with LAMP2, a widely-expressed protein found on cell surfaces as well as in lysosomes. (c) The auto-antibodies bind to LAMP2 on the surface of neutrophils and endothelial cells causing apoptosis. (d) Antibodies to LAMP2 may also mediate adherence of neutrophils to endothelial cells via Fcγ receptors. (e) Subsequent neutrophil degranulation causes endothelial cell necrosis and thus vasculitis.