Gut microbiota profile in systemic sclerosis patients with and without clinical evidence of gastrointestinal involvement

Recent evidence suggests that there is a link between the gut microbial community and immune-mediated disorders. Systemic sclerosis (SSc) is an autoimmune disease characterized by immunonological abnormalities, vascular lesions, and extensive fibrosis. Since the gastrointestinal tract is one of the organs most involved, the goal of this study was to explore the composition of the intestinal microbiota in SSc patients with (SSc/GI+) and without gastrointestinal involvement (SSc/GI-) in comparison to healthy controls (HC). The fecal bacterial composition was investigated by Illumina sequencing of 16 S rRNA gene amplicons. The fecal microbiota of SSc/GI+ subjects was characterized by higher levels of Lactobacillus, Eubacterium and Acinetobacter compared with healthy controls, and lower proportions of Roseburia, Clostridium, and Ruminococcus. The gut microbiota of SSc/GI- subjects was more similar to the microbiota of HC than to that of SSc/GI+ subjects albeit Streptococcus salivarius was over-represented in SSc/GI- fecal samples compared with both SSc/GI+ subjects and controls. Our study reveals microbial signatures of dysbiosis in the gut microbiota of SSc patients that are associated with clinical evidence of gastrointestinal disease. Further studies are needed to elucidate the potential role of these perturbations in the onset and progression of systemic sclerosis, and gastrointestinal involvement in particular.