Microbiome Benchmarking to Identify Perturbations in Multiple Sclerosis II

Inclusion Criteria patients: * Diagnosis of MS (as defined by the 2010 McDonald criteria). * Occurrence of symptoms no longer than 5 years before baseline. * Aged 18-65. * Willingness to participate in the study and to sign the informed consent. Exclusion Criteria patients: * Treatment with high doses of systemic steroids 2 months before baseline. * Use of antibiotics 3 months before baseline. * Chronic gastrointestinal disease (e.g. inflammatory bowel disease, colon cancer). * Other immune-mediated or autoimmune diseases (e.g. rheumatoid arthritis, diabetes type 1 and 2, psoriasis). Additional inclusion criteria for MS patients undergoing a relapse: • Ability to provide a faecal sample within 4 weeks from onset of the first symptoms suggestive of a relapse, before cortisone treatment. A relapse is defined by a new clinical sign or clinical worsening of a previous sign/symptom persisting for \>=24 hours in the absence of fever. Additional exclusion criteria for MS patients undergoing a relapse: * Treatment with cortisone before collection of baseline faecal sample. * Evidence of a relapse less than 2 months before baseline. * Switching disease modifying treatment less than 2 months before baseline. Inclusion criteria healthy controls: * Willingness to participate to the study and to sign the informed consent. * Aged \>=18. Exclusion criteria healthy controls: * Neurodegenerative disorders. * Chronic gastrointestinal disease (e.g. inflammatory bowel disease, colon cancer) or autoimmune diseases (e.g. rheumatoid arthritis, diabetes type 1, psoriasis). * Use of antibiotics 3 months before baseline. * Treatment with high doses of systemic steroids 2 months before baseline.