Despite the limited study of IL-35 function in AAD, expression of both EBI3 and IL12A genes have been reported to be reduced in peripheral blood mononuclear cells from pediatric and adult allergic asthma patients compared with controls, accompanied by decreased plasma IL-35 levels, which inversely correlated with plasma concentrations of the type 2 cytokine IL-4.166,167 These findings suggest that insufficient IL-35 production may be a feature of aberrant type 2 immunity in allergic asthma. Here, IL4 is linked to allergic asthma.