The interleukin-1 receptor antagonist (IL-1RA) is a protein that in humans is encoded by the IL1RN gene.IL-1RA was initially called the IL-1 inhibitor and was discovered separately in 1984 by two independent laboratories.IL-1RA is an agent that binds non-productively to the cell surface interleukin-1 receptor (IL-1R), the same receptor that binds interleukin 1 (IL-1), preventing IL-1 from sending a signal to that cell.A polymorphism of this gene is reported to be associated with increased risk