Since B cells are involved in the pathogenesis by inducing the release of IL-5 from Th2 cells [6,7,8,9,10], an action mechanism of B-cell-depleting therapy in seronegative EGPA myocarditis might include the suppression of IL-5-mediated eosinophilia. The gene discussed is IL5; the disease is eosinophilic granulomatosis with polyangiitis.