HLA-B27
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- Also Known As:
- HLA-B27 Antigen
- Formal Name:
- Human Leukocyte Antigen B27

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At a Glance
Why Get Tested?
To determine whether you have human leukocyte antigen B27 (HLA-B27) on the surface of your cells; to help assess the likelihood that you have an autoimmune disorder associated with the presence of HLA-B27. Autoimmune disorders occur when the immune system mistakenly targets the body’s own cells and tissues.
When To Get Tested?
When you have symptoms of arthritis-like chronic joint pain, stiffness, and inflammation in certain areas of your body, such as your lower back, hips, neck, and chest, or have painful inflammation of the eyes called uveitis, especially if you are male and the symptoms began in your early 30s
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
What is being tested?
HLA-B27 is a specific protein (termed a human leukocyte antigen or HLA) that is found on cell surfaces. The term HLA-B27 is also used to refer to the gene that codes for the HLA-B27 protein. The HLA-B27 test determines the presence or absence of HLA-B27 protein on the surface of a person’s white blood cells.
Human leukocyte antigens are proteins that help the body’s immune system identify its own cells and distinguish between “self” and “nonself.” Everyone has an inherited combination of HLA genes that code for the many antigens present on the surfaces of their cells. The presence or absence of each antigen creates a distinctive HLA combination for each person.
HLA-B27 is found in about 6% of the U.S. population. People with HLA-B27 have an increased likelihood of developing autoimmune diseases such as ankylosing spondylitis (AS), juvenile rheumatoid arthritis (JRA), reactive arthritis (of which one subset is Reiter syndrome), and isolated acute anterior uveitis. HLA-B27 has also been linked with inflammatory bowel disease and a range of other chronic conditions.
Ankylosing spondylitis and reactive arthritis are both chronic, progressive conditions that occur more frequently in men than women. The first symptoms typically occur when a person is in their early 30’s. Often, the initial symptoms of these autoimmune disorders are subtle and may take several years before characteristic degenerative changes to bones and joints are visible on X-rays.
- Ankylosing spondylitis is characterized by pain, inflammation, and a gradual stiffening of the spine, neck and chest.
- Reactive arthritis is a group of symptoms that includes inflammation of the joints, urethra, and eyes as well as skin lesions.
- Juvenile rheumatoid arthritis is a form of arthritis that occurs in children.
- Anterior uveitis is associated with recurring inflammation of the structures of one or both eyes.
While HLA-B27 has not been established as a cause of any of these disorders, there is a higher prevalence of the antigen in those affected. For example, even though only 6% of the population has HLA-B27, 80-90% of people with ankylosing spondylitis are positive for HLA-B27.
Common Questions
View Sources
Sources Used in Current Review
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