The MICROSPA project aims to compare gut microbiota, serum cytokines, and PBMC of patients suffering from Crohn's disease (CD) associated or not to spondylarthritis (SpA). 3 groups of patients will be analyzed: patients suffering from CD alone, patients suffering from SpA alone, patients suffering from CD and SpA. One group of healthy controls will be analysed as a comparator. Fecal microbiota will be determined by bacteriome, virome and fungome NGS sequencing

Inclusion Criteria:

• Age ≥ 18 years.
• Patients will be recruited according to 3 groups:
• Patients with Crohn's disease and axial spondyloarthritis according to the criteria below.
• Patients with Crohn's disease (MC patients) with a diagnosis established according to clinical, biological criteria, radiological, endoscopic and / or histological studies for 3 months. With diagnosis of exclusion of a spondyloarthritis on criteria ASAS and / or New York modified.
• Patients with axial spondyloarthritis (SpA patients) with a diagnosis based on modified ASAS and / or New York criteria with exclusion diagnosis of Crohn's disease.
• Patient with the ability to give free and express informed consent.

Exclusion Criteria:

• History of colonic resection
• Taking antibiotics or colon preparation for colonoscopy within 8 weeks before stool collection (Temporary contraindication = removal possible before colic or first bowel preparation after the start of colonic preparation).
• Ostomy at the time of sampling
• BMI> 30
• extreme diet
• unbalanced diabetes
• Pregnant woman
• Patient under guardianship, under curatorship or under the protection of justice Contacts/Locations Central Contact