Mast Cell Activation Disorders

About Mast Cell Activation Disorders

Mast cells are considered to be the “master regulators” of the immune system and are responsible for immediate allergic reactions; they come from bone marrow and reside in the connective tissue of all vascularized organs and in mucosal tissues in the body. Mast cell activation disorder (MCAD), is an immunological condition in which mast cells inappropriately and excessively release chemical mediators as a hyper-reaction to foreign bodies or injury, sometimes causing anaphylaxis or a near-anaphylaxis attack. The two major forms of mast cell disorders are mastocytosis and mast cell activation syndromes (MCAS). Mastocytosis is a rare disorder characterized by abnormal accumulations of mast cells in the skin, bone marrow and internal organs. There are two main forms of mastocytosis: cutaneous and systemic, and is usually caused by a mutation in the KIT gene. The second type of MCAD is mast cell activation syndrome (MCAS). MCAS can cause a wide range of unpleasant and sometimes debilitating, symptoms in any of the different systems of the body, frequently affecting several systems at the same time. The onset of MCAS is often sudden, affecting both children and adults, and can mimic other conditions. Mast cell activation syndrome can be classified into primary (clonal proliferation), secondary (due to specific stimulus), and idiopathic (no identifiable cause).