Endogenous inhibitor of interleukin-1, q.v.; modulates the normal, acute inflammatory response to infection and injury. First known naturally occurring protein that functions as a specific receptor antagonist of a cytokine. Variably glycosylated, 152 amino acid protein; mol wt 17-25 kDa. Secreted (glycosylated) and intracellular (nonglycosylated) forms have been identified. Structurally homologous with IL-1 and produced by the same cells. Isoln of an IL-1 inhibitor produced by human monocytes: W. P. Arend et al., J. Immunol. 134, 3868 (1985). Isoln from human urine: P. Seckinger et al., ibid. 139, 1541 (1987). Purification: C. H. Hannum et al., Nature 343, 336 (1990). Cloning and expression of human IL-1ra: S. P. Eisenberg et al., ibid. 341. Study of biological function: E. Hirsch et al., Proc. Natl. Acad. Sci. USA 93, 11008 (1996). Therapeutic potential in IL-1-mediated disease: R. C. Thompson et al., Int. J. Immunopharmacol. 14, 475 (1992); C. A. Dinarello, Nutrition 11, 492 (1995). Reviews: W. P. Arend, Adv. Immunol. 54, 167-227 (1993); A. C. Lennard, Crit. Rev. Immunol. 15, 77-105 (1995). Prognostic value in percutaneous coronary intervention: G. Patti et al., Am. J. Cardiol. 89, 372 (2002).
Nonglycosylated, recombinant human IL-1ra expressed in E. coli; mol wt 17 kDa. Prepn: C. H. Hannum et al., EP 343684; eidem, US 5075222 (1989, 1991 both to Synergen). Biological properties: W. P. Arend et al., J. Clin. Invest. 85, 1694 (1990). Clinical trial in sepsis syndrome: C. J. Fisher, Jr. et al., Crit. Care Med. 22, 12 (1994); in rheumatoid arthritis: R. M. Fleischmann et al., Arthritis Rheum. 48, 927 (2003). Series of articles on safety and clinical experience in rheumatoid arthritis: Rheumatology 42, Suppl. 2, ii22-ii40 (2003).
Anti-inflammatory.
Anakinra: Anti-inflammatory (Biological Response Modifier)