TNF and allergic asthma: The involvement of FFA4 in the CpdA-induced suppression of pro-inflammatory cytokines has been shown in allergic asthma (Il-4, Il-5, Il-13, Ifn-g, and Il-17a), atopic dermatitis (Il-4, Il-13, Ifn-g, and Il-17a), and psoriasis (Il-17a, Il-22, Il-23, Il-1b, Ifn-g, and Tnf-a) models using Ffa4 gene KO mice [30,39].