IL17A and allergic disease: Since the information on the role of IFN-λ2 in allergy is very limited, the study that treatment with IFN-λ2 completely halts and reverses the development of collagen-induced arthritis, dramatically reduces numbers of proinflammatory IL-17-producing Th17 and γδ T cells in the joints and inguinal lymph nodes, and restricts recruitment of IL-1b-expressing neutrophils [6] may support the anticipation that IFN-λ2 may play an inhibitory role in allergic airway diseases.