MPO and autoimmune disease: Various reports have suggested the immunomodulatory role of anti-idiotypes in autoimmune disorders.[19–21] In the present study, some significant points, such as the high incidence of anti-ids to antibodies directed to anti-MPO and PR3, along with low BVAS, the low incidence of anti-ids in patients with active disease having a high BVAS and absence of anti-ids in relapse cases having high BVAS along with an inverse correlation of ANCA with anti-ids antibodies, are emerged.