Serum concentrations of the proinflammatory cytokines IL1β, IL6 and TNFα are raised in RA, correlate with disease activity, and fall in response to treatment.12, 13 Furthermore, recombinant IL6 dramatically stimulates the HPA axis.14 Thus, there is the potential for a link between the inflammatory cytokines and circadian cortisol control. The gene discussed is TNF; the disease is rheumatoid arthritis.