[HLA B27-associated rheumatic diseases from the clinical viewpoint]

On the basis of the description of the possible variable courses and symptoms of ankylosing spondylitis, Reiter's syndrome, and reactive arthritides (spondarthritides) frequently produced by intestinal infections, all of which show HLA B27 as the predisposing hereditary antigen in about 90% of the cases, it is discussed whether these conditions represent a disease entity in which additional unknown factors determine the expression and the tendency of the course of the disease.