Although studies have implicated IL-13 in the induction of allergy or asthma, and hepatic fibrosis [46], [47], it has also been shown to suppress inflammation in the setting of proinflammatory immune activation, either by inducing activation of macrophages with anti-inflammatory properties [48], [49] or by inducing TGF-β production from immature myeloid cells [50], [51]. Here, TGFB1 is linked to asthma.