Acostill ( RaDiCo Cohort) (RaDiCo Acostill)

Inclusion Criteria: * Aged over 16 (age\> 16) meeting the diagnostic criteria of Yamaguchi or Fautrel criteria (appendix 5) * Aged 16 years or less (age ≤16 years) fulfilling the 2001 criteria for ILAR systemic form of juvenile idiopathic arthritis * Having signed a consent to participate in the cohort and in the collection of clinical and biological data; in accordance with the regulations, for patients who are minors or adults who are protected, the non-opposition of the legal representatives will be sought. * Affiliated to the "Régime National d'Assurance Maladie". Exclusion Criteria: * Other cause of relapsing infectious fever (such as tuberculosis, toxoplasmosis, deep abscesses, viroses, sepsis) or tumor (such as lymphomas) * Other defined inflammatory rheumatism such as rheumatoid arthritis, psoriatic arthritis, spondyloarthropathies. * Autoimmune inflammatory disease (systemic lupus erythematosus), granulomatosis (sarcoidosis, Blau syndrome), vasculitis (Behçet's disease, nodular arteritis), polymyositis and dermatomyositis. * Well-defined auto-inflammatory syndromes with unambiguous mutations, such as familial Mediterranean fever, cryopyrinopathies, TRAPS, mevalonate kinase deficiency. * Known macrophage activation syndromes of genetic origin. * Patients unable to understand the information leaflet and sign the informed consent form * Patients not affiliated to the "Régime National d'Assurance Maladie"