Interleukin 6 (IL-6) is a potent cytokine, the biological activities of which include the stimulation of immunoglobulin secretion, T cell activation, induction of the acute phase response, activation of megakaryocytes, and pyrogenicity. These biological activities make it a plausible contributor to rheumatoid arthritis. The ability of synoviocytes to synthesise this potential mediator of inflam...