Olive leaf extract (OLE) reduces mast cell mediated allergic inflammation ScienceDirect Mast Cells British Society for Immunology Mast cell responses to pathogens Nature Reviews Immunology 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 Sensitized mast cells for targeted drug delivery and augmented cancer immunotherapy: Cell 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.