In ANCA-associated vasculitis (AAV), the damage is mainly mediated by eosinophilic cationic protein (ECP) and eosinophil-derived neurotoxin (EDN), and the presence of peripheral and tissue eosinophilia has been reported in AAV other than EGPA, in drug-induced vasculitis, and in Kawasaki disease [52,53,54]. This evidence concerns the gene RNASE2 and eosinophilic granulomatosis with polyangiitis.