γγ HLA is an antigen present on chromatin directly related to genetics in human leukocytes and is encoded at different loci. 1973 studies by an American and a British scholar demonstrated that ankylosing spondylitis is associated with the HLA-locus. They found that more than 90% of patients with ankylosing spondylitis carried HIA-B27; HLA-B27 had a strong correlation with ankylosing spondylitis, but finding a positive HLA-B27 did not confirm the diagnosis of ankylosing spondylitis. This is because only 20% of the HLA-B27 positive population has ankylosing spondylitis. Therefore, it is clearly not correct to assume that HIA-B27 positivity means that you will develop ankylosing spondylitis. It should also be noted that nearly 10% of patients with ankylosing spondylitis are also negative for HIA-B27.γγThe diagnosis of ankylosing spondylitis should still be based on clinical symptoms and imaging changes as the main criteria, and a positive HIA-B27 should only be used as an important reference indicator.