What causes the ophthalmologic manifestations of ankylosing spondylitis?

Updated: May 15, 2020
  • Author: Jean Deschênes, MD, FRCSC; Chief Editor: Hampton Roy, Sr, MD  more...
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The exact role of HLA-B27 in the development of uveitis is not precisely known, but several theories for its role in disease exist. The oldest theory is that of molecular mimicry, in which an infectious agent triggers an immune response against autoantigens. The HLA-B27 antigen shares some amino acid homology with proteins from several gram-negative bacteria, including Yersinia enterocolitica, Shigella flexneri, and Chlamydia trachomatis, as well as from gram-negative bacteria found in the GI tract.

Other theories include the arthritogenic peptide theory, in which the immune response is directed against a peptide presented by HLA-B27; the altered self theory, in which a reactive sulfhydryl group on the HLA-B27 molecule interacts with other self peptides, thereby inducing antigenicity; and, finally, the theory that the HLA-B27 allele confers an altered immune response that directly relates to the disease.

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