IL33 and eosinophilic granulomatosis with polyangiitis: 1. Blood eosinophil count or ILC2 and, sST2 or TSLP, and IL-33 were significantly higher in active EGPA than in inactive, at relapse, or in other diseases. 2. EGPA activity correlated with IL-33 and ILC2, but eosinophil count correlated with ILC2 TSLP (but not IL-33).