Mast cell activation syndrome MEpedia 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. Mast Cell Activation Syndrome: A Primer for the Gastroenterologist Digestive Diseases and Sciences Springer Nature Link Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification Information about Mast Cell Activation Syndrome, MCAS Ways to Address Perinatal Mast Cell Activation and Focal Brain Inflammation, including Response to SARS CoV 2, in Autism Spectrum Disorder