Interleukin-1 receptor antagonist (IL-1RA) is a naturally-occurring, inflammatory-inhibitor protein. It inhibits the activity of IL-1alpha and IL-1beta by competitively blocking their binding to type I and type II receptors. IL-1RA is produced by corneal epithelial cells, monocytes, neutrophils, macrophages, and fibroblasts. Therapeutically, IL-1RA may help in the treatment of sepsis, cachexia, rheumatoid arthritis, chronic myelogenous leukemia, asthma, psoriasis, and inflammatory bowel disease. Recombinant Human IL-1RA is a 17.2 kDa protein consisting of 153 amino acid residues.