As previously discussed, tofacitinib, which is stated to be JAK1 and JAK3 selective, is believed to mostly inhibit the common γ-chain receptor family of cytokines, namely IL-2,IL-4,IL-7, IL-9, IL-13, IL-15, and IL-21 [57,62], that are not considered to be key to IBD pathogenesis [63,64]. This evidence concerns the gene JAK1 and inflammatory bowel disease.