Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology
Mast cells are subdivided into 2 types based on proteinase content:
TC mast cells -- Tryptase and Chymase in granules
T mast cells -- Tryptase only granules
Tryptase only, Kit+/CD88-
Dual granules - Tryptase/Chymase
Dual surface markers - Kit+/CD88+
Major cell (10 µm) -- 2 times bigger than basophils (5 µm)
Minute granules (0.2 µm)
More granules (1000) than basophils (80)
Monophorm (round) nucleus
Bigger granules (1.2 µm)
Mast Cell Mediators
The mediators fall into 3 groups remembered by the mnemonic ONC.
BLT 1, 2 receptors
C4, D4, E4
CysLT 1, 2 receptors
What is the most potent bronchoconstrictor?
(E) thromboxane A2 (TXA2)
CysLTs are the most potent bronchoconstrictor agents yet discovered, about 100-1000 times more potent than histamine. The second most potent bronchoconstrictor is thromboxane A2 (TXA2).
Cysteinyl‐LTs and LTB4 are, respectively, the most potent bronchoconstrictor agents and one of the most effective leukocyte chemotaxins yet.
Mast Cell Disorders (presentation on Google drive):