The main effects of IL-1 are Costimulation of T-cell activation by enhancing production of cytokines (eg, IL-2 and its receptor) Enhancement of B-cell proliferation and maturation Enhancement of NK-cell cytotoxicity Induction of IL-1, IL-6, IL-8, TNF, GM-CSF, and prostaglandin E2 production by macrophages Proinflammatory activity by inducing chemokines, ICAM-1, and VCAM-1 on endothelium Induction of sleep, anorexia, release of tissue factor, acute phase reactants, and bone resorption by osteoclasts Endogenous pyrogenic activity Clinical relevance of IL-1 includes For anti-IL-1 beta monoclonal antibody (mAb), treatment of periodic fever syndromes, systemic juvenile idiopathic arthritis, acute gout, and calcium pyrophosphate arthritis (pseudogout) For IL-1 receptor antagonist (IL-1RA), treatment of adults with moderate to severe rheumatoid arthritis and patients with neonatal-onset multisystem inflammatory disease (NOMID) IL-2 is produced by Th1 cells.