Mast Cell Activation Syndrome (MCAS) Symptoms Survey Mast Cell 360 Histamine and TH2 cytokines regulate the biosynthesis of cysteinyl leukotrienes and expression of their receptors in human mast cells Inflammation Research Springer Nature Link 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. GutBrain Inflammation and Disrupted Homeostasis Due to Activation of Mast Cells and Microglia