IL-1RAP also known as IL-1RAcP is a component of the interleukin 1 receptor complex, which initiates signalling events that result in the activation of interleukin 1-responsive genes. IL-1RAP plays a crucial role in the immune response by acting as an accessory protein that associates with the type-1 IL-1 receptor (IL-1RI) to facilitate signal transduction upon binding of pro-inflammatory cytokines IL-1α and IL-1β. This interaction is vital for the activation of downstream signaling pathways, including the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), which is essential for mediating inflammatory responses. Additionally, IL-1RAP exists in two major isoforms: the membrane-bound form (mIL-1RAcP), which promotes signaling, and the soluble form (sIL-1RAcP), which can inhibit IL-1 signaling, highlighting IL-1RAP′s dual role in regulating inflammation.