The interleukin-1 receptor antagonist(IL-1RA) is a protein that in humans is encoded by the IL1RN gene. The human IL1RN gene was localized to the long arm of chromosome 2 at band 2q14.2 by fluorescence in situ hybridization. IL-1RA is a member of the interleukin 1 cytokine family. This protein inhibits the activities of interleukin 1, alpha(IL1A) and interleukin 1, beta(IL1B), and modulates a variety of interleukin 1 related immune and inflammatory responses.