PATIENTS WITH ANKYLOSING-SPONDYLITIS AND HEALTHY RELATIVES DO NOT SHOW INCREASED SMALL-INTESTINAL PERMEABILITY WITH THE LACTULOSE-MANNITOL TEST

Small intestinal permeability was measured in 71 subjects: 26 (24 B27) patients with ankylosing spondylitis (AS); 20 healthy first degree r elatives (13 B27+); 6 patients with active Crohn's disease and 19 heal thy controls. We determined the urinary excretion ratio of two ingeste d sugar probes, lactulose (10 g) and mannitol (0.5 g) by gas-liquid ch romatography. The median lactulose/mannitol excretion ratio in AS pati ents (0.0099) and relatives (0.0090) was not significantly different f rom the median ratio in healthy controls (0.0095). HLA status or use o f NSAIDs did not significantly influence the results. In patients with Crohn's disease, on the other hand, the median lactulose/mannitol rat io (0.021) was significantly increased in comparison to healthy contro ls (0.0095). Our results confirm that the lactulose-mannitol test can be used to demonstrate increased intestinal permeability in Crohn's di sease. For patients with AS and their relatives the lactulose-mannitol test may not be sufficiently sensitive. Alternatively, significantly increased permeability may not occur in most patients with AS.