Are Mast Cells Involved in Autoinflammatory Diseases

Autoinflammatory diseases (AID) are caused by innate immunity dysregulation and characterized by recurrent bouts of fever, frequently associated with digestive, articular or cutaneous symptoms, and sometimes ocular, auricular or neurologic inflammation. The most frequent monogenic AID is Familial Mediterranean fever (FMF).

Despite recent genetic progress AID pathophysiology is only partly understood, especially in the case of unclassified AID.

Mast cells (MC) are innate immune cells associated with a spectrum of disease between systemic mastocytosis and mast cell activation syndrome (MCAS). In MCAS, patients have various symptoms including abdominal pain, bloating, pruritus, flush, anxiety, fatigue, among which some are similar to those seen in patients with AID. The implication of MC has been shown in cryopyrin associated periodic syndrome (CAPS).

Our hypothesis is that MC could be involved in AID pathophysiology,

In order to test this hypothesis, we plan to study :

• clinical MC activation symptoms via a standardized clinical score
• biological MC mediators : by measuring total serum tryptase and histamine in total blood, plasma and urine
• MC infiltration on gastro-intestinal (GI) tract and cutaneous biopsies We will compare clinical MC activation score in AID patients to patients with mastocytosis, with other inflammatory diseases, and with healthy controls.

Inclusion criteria

• Patients >18 years old with Auto-inflammatory diseases already followed up at the CeRéMAIA (french national reference center for autoinflamamtory diseases and AA amyloidosis) of Tenon hospital and included in the JIRcohorte
• Healthy adult controls, age- and sex-matched with MAI patients, and controls with mastocytosis, an immuno-inflammatory disease.
• Subject affiliated to or entitled to a social security scheme
• Collection of the patient's or healthy control's non-opposition

Exclusion criteria

• Subjects unable to answer questions or express themselves
• Subjects who do not speak French
• Subject deprived of liberty or under legal protection.