Moreover, multiple regression analysis showed no association of the cytokines IL-1β, IL-2, IL-4, IL-5, IL-8, IL-12p70, IL-17, TNFα, IFN-γ, IL-10, and IL-13 with primary MS-related fatigue, with the exception of the pro-inflammatory cytokine IL-6. This evidence concerns the gene CXCL8 and myeloid sarcoma.