Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification Effects of Dietary Components on Mast Cells: Possible Use as Nutraceuticals for Allergies? AAAAI Mast Cell Disorders Committee Work Group Report: Mast cell activation syndrome (MCAS) diagnosis and management Journal of Allergy and Clinical Immunology Mast cells are hypersensitive immune cells that release histamine and other inflammatory mediatorsoften in response to oxidative stress, environmental toxins, and immune imbalance. Many patients with MCAS have low levels of glutathione.