Frontiers Glutathione deficiency in the pathogenesis of SARS CoV 2 infection and its effects upon the host immune response in severe COVID 19 disease AZD5904 Mast Cell Activation Syndrome (MCAS) Dr. Todd Maderis 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.