The significance of HL-A W27 in ankylosing spondylitis and Reiter's syndrome with three family studies.

So as to test the diagnostic significance of tissue typing in an Australian population the HL-A antigens of forty-seven patients with Ankylosing Sondylitis and six patients with Reiter's Syndrome were compared with those found in three hundred and six controls. Since HL-A W27 was found in 92% of the patients with Ankylosing Spondylitis and all patients with Reiter's Syndrome it is concluded that these diagnoses should be questioned if this antigen cannot be demonstrated. In three family studies it was apparent that Ankylosing Spondylitis only occurred in those who had inherited HL-A W27 so that the absence of the antigen may help to identify those family members who will not develop the disease. Notwithstanding the association demonstrated the data argue against a close and simple linkage between the antigen and these diseases.