To find out whether you have human leucocyte antigen B27 (HLA-B27) on the surface of your cells; to help assess whether you might have an autoimmune disorder associated with the presence of HLA-B27.
When you have symptoms of chronic inflammation, pain, and stiffness in certain areas of your body, such as your back, neck, and chest, or the interior portion of your eyes uveitis, especially if you are male and the symptoms began between late teens and your early 30s.
A blood sample taken from a vein in your arm.
None.
Every nucleated cell in your body has proteins protruding from the cell surface called human leucocyte antigens (HLA). These proteins are very diverse. Several thousand different types are known. Everybody has a number of different types of these proteins on each cell and together they make up an individual’s “Tissue Type”. One common HLA protein is HLA-B27. Its prevalence varies considerably across the world but it is found in about 8% of the UK population.
HLA proteins are of great importance to the human immune system. They enable it to distinguish our own cells and proteins from those of bacteria, viruses and other “invaders” and so enable it to identify these invaders for attack whilst avoiding attacking its own cells.
The test determines the presence or absence of HLA-B27 on the surface of a person's white blood cells (leucocytes). Sometimes a genetic test is used but the test result is essentially the same.
HLA-B27 is found in about 8% of the UK population. Its presence has been associated with several autoimmune disorders. The most common of these disorders is ankylosing spondylitis (AS). In the UK about 95% of people with AS have the HLA-B27 protein expressed on their cells (they are “HLA-B27 positive”). Other disorders that have an association with the presence of HLA-B27 include juvenile rheumatoid arthritis (JRA), reactive arthritis (including Reiter syndrome), and isolated acute anterior uveitis. HLA-B27 is also more common in people with spondylitis associated with inflammatory bowel disease and psoriatic arthritis. HLA-B27 has not been established as a cause of these disorders but HLA-B27 positivity is more common in people with these disorders than in people without them. However, it is important to realise that HLA-B27 is very common and so most people who are HLA-B27 positive do not have any of these disorders.