CXCL8 and rheumatoid arthritis: When intracellular levels of IL-6, TNF-α, IL-1β and IL-8 in CD14 monocytes isolated from active patients with RA were assessed, there was a reduction in TNF-α, IL-6 and IL-1β, all approximately by 25%, and reduced IL-8 level by 20% without an effect on MCP-1 expression [6].