Effect of probiotics on gastrointestinal symptoms and immune parameters in systemic sclerosis: a randomized placebo-controlled trial

Abstract Objectives Changes in the intestinal microbiota have been associated with the pathogenesis of SSc. Probiotics act by modulating the microbiome and the immune response. This study aimed to evaluate the efficacy of probiotics on gastrointestinal (GI) symptoms and immune responses in SSc patients. Methods Patients with SSc with a moderate–severe total score on the University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract 2.0 (UCLA GIT 2.0) instrument were randomly assigned to receive a daily dose of probiotics (Lactobacillus paracasei, Lactobacillus rhamnosus, Lactobacillus acidophillus and Bifidobacterium lactis, 109 colony-forming units per capsule) or placebo for 8 weeks. The primary endpoint was improvement in the UCLA GIT 2.0 total score after 8 weeks. Secondary outcomes included changes in Th1, Th2, Th17 and regulatory T cell circulating levels and in the HAQ Disability Index (HAQ-DI) score. Parameters were assessed at baseline and after 4 and 8 weeks of treatment. Results A total of 73 patients were randomized to receive probiotics (n = 37) or placebo (n = 36). After 8 weeks, there was no difference in the UCLA GIT 2.0 score between the two groups. At week 8, the probiotic group showed a significant decrease in the proportion of Th17 cells compared with placebo (P = 0.003). There was no difference in the proportion of Th1, Th2 and regulatory T cells or in the HAQ-DI score between the groups. Conclusion Probiotics did not improve GI symptoms in SSc patients. The reduction in Th17 cell levels suggests an immunomodulatory effect of probiotics on SSc. Trial registration ClinicalTrials.gov (http://clinicaltrials.gov), NCT 02302352.