Mnemonics: Mast Cells and Basophils

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
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

TC
Tryptase/Chymase, Kit+/CD88+

T
Tryptase only, Kit+/CD88-

D
Dermis
Dual granules - Tryptase/Chymase
Dual surface markers - Kit+/CD88+

M
Mast cells
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

B
Basophils
Blood circulation
Bigger granules (1.2 µm)
Bilobar nucleus

Mast Cell Mediators

The mediators fall into 3 groups remembered by the mnemonic ONC.

ONC:
Old
New
Cytokines

Leukotriene receptors

Leukotriene
B
B4
BLT 1, 2 receptors

Leukotriene
C
C4, D4, E4
CysLT 1, 2 receptors

What is the most potent bronchoconstrictor?

(A) LTB4

(B) LTC4

(C) acetylcholine

(D) histamine

(E) thromboxane A2 (TXA2)

(F) methacholine

Answer: B

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):



Published: 01/24/2008
Updated: 05/12/2009