HLA-B27 is a genetic marker associated with diseases in which group?

• A. Autoimmune hemolytic anemia
• B. Systemic lupus
• C. Rheumatoid arthritis
• D. Spondyloarthropathies

Answer: (D)

HLA-B27 is a class I HLA antigen most strongly linked to spondyloarthropathies, a group of inflammatory diseases that primarily affect the spine and entheses, including ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and enteropathic arthritis. This association helps explain why HLA-B27 testing is commonly considered when evaluating inflammatory back pain and related symptoms. In contrast, rheumatoid arthritis is more closely associated with HLA-DR4, and systemic lupus erythematosus with HLA-DR2/DR3, while autoimmune hemolytic anemia does not define a single HLA-B27–related syndrome. Therefore, the diseases most linked to HLA-B27 belong to the spondyloarthropathies.