Asthma is a Th2 cell‐mediated type 2 inflammation, lepromatous leprosy also characterized by the enrichment of Th2 cells and cytokines,58, 59 wherein IL‐18 activates Th2 cells to produce IL‐4 and IL‐13 in the absence of IL‐12 or IL‐15.60 This evidence concerns the gene IL18 and asthma.