Mast Cell Degranulation

Mast cell degranulation is a cellular process in which mast cells release the contents of their cytoplasmic granules into the extracellular space. This process is central to inflammatory and allergic responses, as it rapidly delivers bioactive mediators such as histamine, proteases, and cytokines that modulate vascular permeability, recruit immune cells, and trigger symptoms like itching or swelling. Degranulation can be triggered by activation of several surface receptors on mast cells, including FcεRI, MRGPRX2/B2, and P2RX7. Because inappropriate or excessive mast cell degranulation underlies many allergic diseases—including asthma, urticaria (hives), anaphylaxis—this process is a major target for drug development. Therapies may aim to block key receptors like FcεRI or inhibit downstream signaling pathways that lead to exocytosis.

Block key receptors like FcεRI or inhibit downstream signaling pathways that lead to exocytosis.