Mast Cell Activation Syndrome and Its Impact on the Lymphatics Did you know one single mast cell can release chemicals that affect your skin, gut, heart, brain, and immune system all at once? That's why MCAS can feel so overwhelming, the Glutathione synthesis primes monocytes metabolic and epigenetic pathway for glucan trained immunity ScienceDirect 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. Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification