IL4 and rheumatoid arthritis: To further investigate the impact of catecholamines on cytokine production of human T lymphocyte populations of age-matched healthy donors (HDs) and patients with RA, peripheral circulating T cells were activated and the production of the cytokines interleukin (IL)-4, IL-10, interferon (IFN)-γ, and tumour necrosis factor (TNF)-α was studied upon co-incubation with epinephrine (EPI) or NE.