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. MCAS Bundle Consult Dr. Anderson Long Covid And MCAS: Breaking Down The Connection Understanding Mast Cell Activation Syndrome (MCAS): Connections to MTHFR Gene Mutations, the Presence of Hypergammaglobulinemia and the Gut Microbiome Medical Spa & Wellness By Michelle NP