- Human leukocyte antigen (HLA) B27
- Class I surface antigen encoded by the B locus in the major histocompatibility complex (MHC) on chromosome 6.
- HLA-B27 is strongly associated with ankylosing spondylitis (AS), and other associated inflammatory diseases referred to as "spondyloarthropathies".
- Diseases associated with the HLA-B27 subtype can be remembered with the mnemonic PAIR- Psoriasis, Ankylosing spondylitis, Inflammatory bowel disease, and Reactive arthritis.
