MPO and autoimmune vasculitis: LITTLE et al. mixed purified MPO with the Freund’s complete adjuvant and gave the immunoWistar-Kyoto (WKY) rat abdominal injection to establish the ANCA-related experimental autoimmune vasculitis (the autoimmune vasculitis, EAV) rat model [6] to produce high-titer anti-MPO antibodies that cross-react with rat MPO.