RYL-552S（Cat No.:I043849）is a selective inhibitor of the Janus kinase 1 (JAK1) enzyme, which plays a pivotal role in immune cell signaling and inflammation. By inhibiting JAK1, RYL-552S effectively modulates immune responses and reduces the production of pro-inflammatory cytokines. This compound shows potential in the treatment of autoimmune diseases, such as rheumatoid arthritis and psoriasis, as well as inflammatory conditions. Its specificity for JAK1 allows for targeted therapeutic action, minimizing the impact on other JAK family members, thus offering a promising approach for managing chronic inflammatory diseases.