Intestinal permeability in patients with ankylosing spondylitis and their healthy relatives.

Patients with AS were previously found to have increased intestinal permeability using the 51Cr-EDTA resorption test. In order to discover whether this alteration has taken place prior to, or as a consequence of the disease, we studied the intestinal permeability to 51Cr-EDTA in 20 patients with AS, 65 of their healthy relatives, and 25 normal volunteers. We also considered the HLA B27 antigen, the serum immunoglobulin A levels, the disease activity, the existence of peripheral arthritis, the ESR, the CRP values and the intake of drugs at the time of study. Gut permeability was found to have increased in the patients and their healthy relatives compared to the control group. No difference in gut permeability was found between patients and relatives regardless of whether they had the HLA B27 antigen or not. The increased intestinal permeability in the patients had no relation to the disease activity, to the presence of peripheral arthritis or to the intake of NSAIDs. Gut permeability was shown to bear no relation to IgA levels, ESR or CRP. Our findings suggest that the increase in gut permeability in AS patients and their relatives is a primary defect and may be an aetiologic factor in this disease.