EGPA is classified as a Th2-cytokine-mediated disease, and Th2 cytokines (such as IL-4, IL-5, and IL-13) and CCL26, a chemokine released from vascular endothelial cells, are responsible for eosinophil infiltration into tissues [95]. This evidence concerns the gene IL5 and eosinophilic granulomatosis with polyangiitis.