The term gut microbiota describes the entire intestinal microbial communities. Studies have established the important role played by the gut microbiome in modulating vital functions of the healthy host. The physiological effects of the microbiota for the host are, for the most part, beneficial. In several pathologies, an imbalance in the composition of the microbiota has been demonstrated.

Systemic sclerosis is an autoimmune, disorder of the connective tissue, characterized by vascular lesions, immunological abnormalities, and fibrosis of skin and internal organs As in many inflammatory diseases, there are painful digestive manifestations in systemic scleroderma that affect up to 90% of patients. The exact pathophysiology of the digestive involvement in systemic sclerosis is uncertain. The digestive manifestations of systemic sclerosis are frequent and can affect the entire digestive system.

However, there are few studies of the intestinal microbiota in this disease, which seems to be part of the same continuum of diseases with abnormalities of innate immunity. By analogy with chronic inflammatory bowel diseases, particularly Crohn's disease, we have raised the question of the existence of dysbiosis during scleroderma which could lead to episodes of acute, severe and recurrent inflammation of the peritoneum under the influence of triggering factors. The long-term prospects would be to look for ways to prevent attacks or to treat them more rapidly and effectively by using therapeutic targets in the intestinal microbiota.

The study population will be seen in the usual care setting, identically to all patients with systemic sclerosis treated in the department.

In case of an inflammatory disease outbreak, and depending on its severity, the patient will be seen again in consultation or hospitalized. Appropriate complementary examinations (biology, imaging, endoscopy) will be carried out and the treatment adapted.

Inclusion Criteria:

• Age ≥ 18 years old
• Patient with a confirmed diagnosis of systemic sclerosis according to international criteria, before or after the start date of this study.
• Non-opposition of the patient

Exclusion Criteria:

• Subject under guardianship, curatorship or safeguard of justice
• Subject with state medical aid (AME)
• Subject does not speak French
• Subject unable to answer questions or express himself/herself
• Taking antibiotics or a colonic preparation within 6 weeks prior to stool collection will be a temporary contraindication to stool collection. The patient may be included, other usual care samples may be taken, but the stool sample will be deferred and taken at a later date.

Patients with systemic sclerosis treated in the Internal Medicine Department of Saint Antoine Hospital and patients who will be newly diagnosed within 2 years after the beginning of the biological collection.