HLA-B38: HLA-B38 (B38) is an HLA-B serotype. The serotype identifies the B*38 allele products of the HLA-B gene-locus.Sacroiliac joint dysfunction: Sacroiliac joint dysfunction, also called sacroiliac joint disorder, sacroiliac joint disease, sacroiliac joint syndrome or sacroiliac syndrome, or "sacroilliac dysfunction and instability", generally refers to pain in the sacroiliac joint region that is caused by abnormal motion in the sacroiliac joint, either too much motion or too little motion. It typically results in inflammation of the sacroiliac joint, and can be debilitating.SpondylitisFibroblast-like synoviocyte: Fibroblast-like synoviocytes (FLS) represent a specialised cell type located inside joints in the synovium. These cells play a crucial role in the pathogenesis of chronic inflammatory diseases, such as rheumatoid arthritis.ACR score for rheumatoid arthritis: ACR score is a scale to measure change in rheumatoid arthritis symptoms. It is named after the American College of Rheumatology.