Prospective Longitudinal Cohort Study of Vasculitis Patients

Inclusion Criteria: * Adult patients (age over 18 years), * Patients with vasculitis, as defined in the Chapel Hill International Nomenclature as revised in 2012, * Patients included at an active phase of the disease, either the initial flare or a relapse, * Patients who have been informed and have signed the consent * Pregnant and breastfeeding women may be included in the study, * Affiliated to a social security system (beneficiary or entitled person). Exclusion Criteria: * Refusal of consent or inability to obtain consent, * A patient who is insane or not entitled, for psychiatric reasons or intellectual impairment, to receive information about the protocol and to give informed consent, * Patient under guardianship / curators * Patient on state medical assistance (AME) * Hemoglobin less than 7 g/dl at the time of sampling, * Hemoglobin level less than 9 g/dl at the time of sampling if the patient has respiratory or cardiovascular disease, * Patient weighs less than 18 kg. * Parallel participation in an interventional protocol is permitted.