HLA B27 Disease Association Blood Test

HLA-B27 is strongly associated with ankylosing spondylitis (Marie-Strumpell disease). HLA-B27 shares homology with a Klebsiella protein and may imply a bacterial pathogenesis to ankylosing spondylitis. A patient with consistent clinical and radiographic findings who is B27-positive has a greater chance of having or developing ankylosing spondylitis than a negative patient. The antigen is not causative, however, and 10% of normal subjects are B27-positive. This test should not be considered a screening procedure for ankylosing spondylitis. The antigen is less strongly associated with Reiter syndrome and other arthritides than with ankylosing spondylitis. It has been linked with congenital deficiency of C4 and C2, and with adrenal hyperplasia.