Diagnostic criteria of mast cell activation syndrome Download Scientific Diagram Update on Mast Cell Activation Syndrome (MCAS) Black & Kletz Allergy 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 How Mycotoxins Trigger Mast Cell Activation and Brain Inflammation