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. Information about Mast Cell Activation Syndrome, MCAS 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, neck pain and the vagus nerve Frontiers Mast Cell Activation in Brain Injury, Stress, and Post traumatic Stress Disorder and Alzheimer's Disease Pathogenesis Invisible Pain Series: Mast Cell Activation Syndrome POGO Physio Gold Coast