In 2002, Xiao et al. established a murine model showing the direct pathogenic role of ANCA in MPO-AAV; injection of anti-MPO IgG from MPO-deficient mice immunized with murine MPO into immunodeficient mice or wild-type mice definitely induced pauci-immune necrotizing and crescentic glomerulonephritis (NCGN) (37). The gene discussed is MPO; the disease is crescentic glomerulonephritis.