These cell subsets can release chemokines and inflammatory cytokines, such as CXCL10, CCL2, CCL20, IL-17, IL-12, IFN-γ, IL-1β, IL-6, TGF-β and IL-10, which are significantly increased in the milk of dairy ruminants with mastitis [21, 22]. This evidence concerns the gene IL17A and mastitis.