Immune function in ankylosing spondylitics and their relatives: influence of disease and HLA B27

So as to distinguish the separate influences of ankylosing spondylitis (AS) and possible HLA B27 associated immune response genes on immune response patterns, a battery of immunological tests were performed on fourteen patients with AS and their first-degree relatives. Previously unrecognized AS was detected by clinical and radiological means. Individuals with ankylosing spondylitis had significantly higher serum IgG and IgA concentrations than both their B27 positive and B27 negative relatives. B27 positive relatives had significantly lower phytohaemagglutinin (PHA) lymphocyte transformations than B27 negative relatives (P less than 0.01), while there was no difference between the ankylosing spondylitic and B27 positive groups. Antibody titres to Streptokinase/Streptodornase were significantly higher in the B27 positive individuals, with or without AS, than their B27 negative relatives (P less than 0.005 and P less than 0.02 respectively). These results show that serum immunoglobulin differences were associated with disease, while differences in PHA stimulation and varidase antibody titres were associated with the B27 antigen. These findings may indicate the presence of HLA associated immune response genes including those involved with reactions to a particular antigenic component of Streptokinase/Streptodornase.