We have recently shown that early IL-4 production by B cells influences type 2 CD4 T-cell differentiation in lymph nodes, which leads to protective type 2 responses against certain parasitic infections.28, 29, 30 Given the complexity around the importance of B cells in allergic asthma, we set to investigate the role of IL-4Rα signaling, specifically in B cells, during HDM-induced allergic asthma. This evidence concerns the gene IL4 and parasitic infectious disease.