IL18RAP (interleukin 18 receptor accessory protein) functions as a non-ligand-binding coreceptor in the IL-18 receptor complex that is essential for IL-18-dependent signal transduction. Upon IL-18 stimulation, IL18RAP associates with IL-18R1 to form a functional heterodimer that triggers NF-κB and JNK activation 1. The protein facilitates IL-18-mediated interferon-gamma (IFN-γ) synthesis from T-helper 1 cells and promotes immune cell infiltration, including M1 macrophages and CD8+ T cell populations 2. Clinically, IL18RAP dysregulation is implicated in multiple diseases. In cancer, elevated IL18RAP expression correlates with poor prognosis and promotes tumor immune evasion through NF-κB-dependent upregulation of chemokines (CXCL1, CXCL5), facilitating neutrophil and macrophage recruitment while suppressing CD8+ T cell infiltration 12. IL18RAP serves as a biomarker for immunotherapy response prediction across cancer types 2. Genetic variants in IL18RAP (rs917997, rs1420106) are established risk factors for celiac disease and Crohn's disease in European populations 34. Additionally, IL18RAP genetic variants associate with extranodal natural killer T-cell lymphoma susceptibility, with risk variants increasing IL18RAP expression and promoting cell proliferation 5. In rheumatoid arthritis, IL18RAP expression predicts anti-TNF treatment response, with higher expression correlating with better treatment outcomes 6.