CXCL8 and rheumatoid arthritis: The levels of IFN-α, IFN-γ, IL-10, IL-12P70, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, and TNF-α differed among patients with RA treated with biologics (P < .001, P = .006, P = .013 respectively).