If other systemic vasculitides are suspected, the search for antibodies against the cytoplasm of neutrophilic leukocytes (ANCA) should be made, whereby there is an association between EGPA and microscopic polyangiitis (MPA) with p-ANCA (anti-MPO-ANCA) and GPA with c-ANCA (anti-PR3-ANCA). Here, PRTN3 is linked to microscopic polyangiitis.