HLA-B27

The test is indicated when there are symptoms such as joint pain and stiffness, chronic inflammation in areas such as the back, knees and elbows, or a painful inflammation of the eye called uveitis, especially in male patients whose symptoms began early (before the age of 30).

The test does not require any preparation

HLA-B27 is a specific protein belonging to the HLA (human leucocyte antigen) family found on the surface of cells. The term HLA-B27 is also used to refer to the gene coding for the HLA-B27 protein. The test determines whether the human B27 antigen is present on the surface of white blood cells in a blood sample taken from a vein.

 

Human leucocyte antigens (HLA) allow the immune system to tell the body’s “own” cells from foreign ones; they therefore distinguish “self” from “non-self”. Each person has a specific combination of HLA antigens, present on the surface of white blood cells and other nucleated cells, that is unique to them.

 

The HLA-B27 antigen is found at varying frequencies in the world population, and in about 8% of white people. Its presence is associated with autoimmune diseases such as ankylosing spondylitis, juvenile rheumatoid arthritis, reactive arthritis and acute anterior uveitis. HLA-B27 is also found in patients with inflammatory bowel disease and other chronic diseases.

 

Ankylosing spondylitis and reactive arthritis are both chronic, progressive diseases that are more common in men. The first symptoms appear early, usually before the age of 30. These early symptoms are often subtle and difficult to identify, and the characteristic bone and joint changes can be seen on X-rays only after several years.

 

Ankylosing spondylitis is characterised by pain, inflammation and gradual stiffening of the spine, neck and chest.

Reactive arthritis (Reiter’s syndrome) is characterised by a group of symptoms including inflammation of the joints, urethra and eyes, as well as skin lesions.

Juvenile rheumatoid arthritis is a form of arthritis that starts early in life

Acute anterior uveitis is associated with recurrent inflammation of one or both eyes

Although the HLA-B27 antigen does not cause these diseases, its presence has been associated with them. For example, although only 6% of people have HLA-B27, 80-90% of people with ankylosing spondylitis are positive for this antigen