IL4 and eosinophilic granulomatosis with polyangiitis: In a study of bronchoalveolar lavage fluid (BALF) in EGPA and bronchial asthma patients, EGPA had a Th2 response compared to bronchial asthma, and clinical parameters of disease activity were strongly correlated with the expression of IL-4, IL-5, IL-10, and STAT5A [20].