{Reference Type}: Journal Article {Title}: Negative regulator IL-1 receptor 2 (IL-1R2) and its roles in immune regulation of autoimmune diseases. {Author}: Zhang Y;Liu K;Guo M;Yang Y;Zhang H; {Journal}: Int Immunopharmacol {Volume}: 136 {Issue}: 0 {Year}: 2024 Jul 30 {Factor}: 5.714 {DOI}: 10.1016/j.intimp.2024.112400 {Abstract}: The decoy receptor interleukin 1 receptor 2 (IL-1R2), also known as CD121b, has different forms: membrane-bound (mIL-1R2), soluble secreted (ssIL-1R2), shedded (shIL-1R2), intracellular domain (IL-1R2ICD). The different forms of IL-1R2 exert not exactly similar functions. IL-1R2 can not only participate in the regulation of inflammatory response by competing with IL-1R1 to bind IL-1 and IL-1RAP, but also regulate IL-1 maturation and cell activation, promote cell survival, participate in IL-1-dependent internalization, and even have biological activity as a transcriptional cofactor. In this review, we provide a detailed description of the biological characteristics of IL-1R2 and discuss the expression and unique role of IL-1R2 in different immune cells. Importantly, we summarize the role of IL-1R2 in immune regulation from different autoimmune diseases, hoping to provide a new direction for in-depth studies of pathogenesis and therapeutic targets in autoimmune diseases.