The interleukin-18 receptor (IL-18R) is an interleukin receptor of the immunoglobulin superfamily. IL-18R is a heteromeric complex of alpha- and beta-chains encoded by the genes IL18R1 and IL18RAP respectively. The interleukin-18 receptor (IL-18R) is an interleukin receptor of the immunoglobulin superfamily. IL-18R is a heteromeric complex of alpha- and beta-chains encoded by the genes IL18R1 and IL18RAP respectively. Endometrial IL-18 receptor mRNA and the ratio of IL-18 binding protein to interleukin 18 are significantly increased in adenomyosis patients in comparison to normal people, indicating a role in its pathogenesis.