1. What causes the autoimmune disorders associated with HLA-B27?
In most cases, the cause is not known. However, in some cases of reactive arthritis, there is an association between a previous infection by a microorganism, such as Chlamydia, Campylobacter, Salmonella, Ureaplasma, or Yersinia, and the beginning of the disease. It is thought that similarities between the HLA-B27 antigen and the antigens found on the surface of the microorganisms trigger the immune system to fight both the microorganism and the person's own tissues, launching the autoimmune disorder after the resolution of the infection.
2. Can I be tested for HLA-B27 in my doctor's office?
HLA-B27 testing requires specialized equipment and expertise to perform. It is not typically performed in a doctor's office and is not offered by every laboratory. In most cases, your blood sample will be sent to a reference laboratory.
Routine testing of the general public is not recommended. Usually only those with symptoms should be tested. A positive HLA-B27 in a person who does not have symptoms or a family history of HLA-B27-associated disease is not clinically significant. It does not help predict the likelihood of developing an autoimmune disease. Occasionally a family member of a person who is positive for HLA-B27 and has an autoimmune disorder may be tested, but the test result cannot be used to predict whether the tested person will develop a related autoimmune disease.
This article was last reviewed on 15 February 2011. | This article was last modified on 20 October 2011.
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