Increased intestinal permeability in ankylosing spondylitis--primary lesion or drug effect?

We have found increased small intestinal permeability to 51Cr-ethylenediaminetetra acetate in patients with ankylosing spondylitis compared with controls. There is no significant difference between patients with ankylosing spondylitis and patients with rheumatoid arthritis taking non-steroidal anti-inflammatory drugs (NSAID). The increased intestinal permeability in ankylosing spondylitis is independent of disease activity. These findings suggest that the increased permeability is caused by NSAID treatment and is probably not a primary lesion of small bowel mucosa.