A functional Irf8 deficiency has been associated with immunodeficiency, while a mechanistic association with MS pathogenesis has been described in Yoshida et al. [54] making use of mice with experimental autoimmune encephalomyelitis (EAE); moreover, genetic variants on the Irf8 gene-coding region has been linked to MS genetic susceptibility [55,56]. Here, IRF8 is linked to immunodeficiency disease.