OBJECTIVES: To assess the composition of gut microbiota in Italian and Dutch juvenile idiopathic arthritis (JIA) patients at baseline, in inactive disease and persistent activity, compared to healthy controls.
METHODS: In a prospective, multicenter, observational cohort study, fecal samples were collected of 78 Italian and 21 Dutch treatment-naïve JIA patients at baseline with less than 6 months disease duration and compared to 107 geography-matched samples of healthy children. Furthermore, 44 follow up samples in inactive disease and 25 in persistent activity were analyzed. Gut microbiota composition was determined by 16S rRNA-based-metagenomics. The α- and β-diversity were computed, and log-ratios of relative abundance were compared between patients and healthy controls using random forest models and logistic regression.
RESULTS: Italian baseline samples showed reduced richness compared to healthy controls (p <0.001). Random forest distinguished Italian baseline samples from controls and suggested differences between Dutch samples and controls (area under the curve >0.99 and 0.71, respectively). Mainly the Operational Taxonomic Units (OTUs) Erysipelotrichaceae (increased in patients), Allobaculum (decreased) and Faecalibacterium prausnitzii (increased) showed different relative abundance in Italian baseline samples compared to controls after controlling for multiple comparisons. Some OTUs differed between Dutch samples and healthy controls, but no evidence remained after controlling for multiple comparisons. No differences were found in paired analysis between Italian baseline and inactive disease samples.
CONCLUSIONS: We found evidence for dysbiosis in JIA patients. Only patient/control status, age and geographical origin appeared to be drivers of the microbiota profiles, regardless of disease activity stage, inflammation and autoimmunity markers. This article is protected by copyright. All rights reserved.