HLA (Human Leukocyte Antigen) B27 is a protein found on the surface of white blood cells. This protein helps white blood cells to distinguish their structure from foreign matter. So it helps to distinguish between self and non self. The HLA B27 test is used to investigate the presence of this protein in the white blood cells. This blood test looks for HLA-B27, proteins called antigens. They are found on the surface of white blood cells that fight infection. The protein is also called human leukocyte antigen B27 (HLA-B27). Human leukocyte antigens (HLAs) are proteins that help the body's immune system to tell the difference between its own cells and foreign, harmful substances. If you have HLA-B27, you may have an autoimmune disease. An autoimmune disease is when your immune system attacks your own cells. The most common autoimmune diseases associated with HLA-B27 antigens:
Ankylosing spondylitis is a form of arthritis affecting the spine Juvenile arthritis in children
WHY IS HLA-B27 TEST PERFORMED?
If your doctor suspects ankylosing spondylitis, you may need this test. This can cause pain and stiffness in your back, neck, or chest. Symptoms are more common in men in their early 30s. You may also need this test if you are transplanting an organ or tissue. For example, this can make a donor kidney or bone marrow transplant. Your donor's HLA antigens must match yours for successful transplantation.