Increased gut permeability in juvenile chronic arthritides. A multivariate analysis of the diagnostic parameters

This study was aimed at evaluating intestinal permeability (IP) in patients with oligoarticular juvenile idiopathic arthritis (o-JIA), spondyloarthropathy (SpA) associated with inflammatory bowel disease (IBD) and other forms of juvenile-onset chronic arthritiis (OIA) using the lactulose/mannitol (L/M) test in comparison with other non-invasive parameters of gut involvement.

A series of 26 children affected with o-JIA and 14 with either SpA/IBD or OIA were assessed for IP. The urinary L/M ratio was measured by gas chromatography. The erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and faecal alpha 1 antitrypsin concentrations were also evaluated. Ten o-JIA patients displayed active arthritis while in 16 the disease was under control. Among the OIA patients, 11 were affected with psoriatic arthritis and the remaining 3 with chronic reactive arthritis. 14 patients with SpA-IBD had active synovitis or spine inflammation. 14 eo-pJCA and 22 OIA and SpA-IBD patients, respectively, were receiving NSAID therapy.

The mean L/M ratios for the Spa-IBD (0.07 +/- 0.02, mean +/- SD), OIA (0.05 +/- 0.02) and o-JIA (0.04 +/- 0.02) patients were significantly higher (p < 0.001, p = 0.022 and p = 0.01, respectively) than those found in controls (0.02 +/- 0.01). Logistic regression analysis disclosed a positive correlation between the L/M ratio and the presence of gastrointestinal manifestations (p = 0.011). The type of disease (p = 0.28), the disease activity in the JCA patient group (p = 0.24) and NSAID administration (p = 0.210) did not seem to significantly influence the L/M ratio.

All of the subtypes of juvenile chronic arthritides that we studied displayed an increased IP. Hence, gut wall inflammation (albeit asymptomatic) may also be present in o-JIA patients. The SpA-IBD patients with gastrointestinal symptoms displayed the highest mean L/M ratio values. The L/M test seemed to correlate with histopathological features of the gut mucosa. The L/M ratio was shown to be a highly sensitive but poorly specific test for predicting gut inflammatory disease compared to other non-invasive screening tests.