HLA-B 27

Medical information of HLA B27

HLA B27 antigen exists on the surface of the body’s white blood cells and other nucleated cells. If a patient has positive HLA B27 and has symptoms such as chronic pain, inflammation and /or degenerative changes to his bone then it supports a diagnosis of Ankylosing Spondylitis, Reiter’s syndrome or another autoimmune disorder that is associated wtih the presence of HLA B27.

However certain percentage of patients with each disorders will be HLA B27 negative.

A positive HLA B27 in a person who does not have symptoms or a family history of HLA B27 associated disease in not clinically significant. HLA B27 is found in 5-7% of caucasians who do not have an autoimmune disorder.

HLA B7 can cross react with anti HLA B27 antibody giving false positive test. In such cases confirmatory microlymphocytotoxicity test or using PCR is essential.