IFNA2 and juvenile idiopathic arthritis: We therefore analyzed 41 serum samples from JIA patients for IL-1β, IL-18, as well as IFN-α2, IFN-γ, TNF-α, MCP-1 (CCL2), IL-6, IL-8 (CXCL8), IL-10, IL-12p70, IL-17A, IL-23 and IL-33.