Lack of association of HLA B27 with radiographic sacroiliitis in inflammatory bowel disease.

In 89 patients with inflammatory bowel disease, only one out of 11 patients with radiographic sacroiliitis was found to possess the HLA B27 antigen, while three out of four patients with ankylosing spondylitis were B27 positive. This suggests that sacroiliitis in inflammatory bowel disease may not always be a precursor of ankylosing spondylitis.