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664 ParT FivE Allergic diseases
1 1 2 2 3 3
Ca 2+ Ca 2+ Ca 2+
Resting mast cell Sensitization Antigen addition
ACTIVATION
(one antigen/IgE/FcεRI complex is shown)
4 4
Extracellular
Ca 2+ calcium
Ca 2+ flux
Ca 2+
5 5 5
DESENSITIZATION
(11 step protocol)
Degranulation
Ca 2+ (pre-formed
Ca 2+ mediators)
Ca 2+ Ca 2+
6 6
Ca 2+ Newly generated
Arachidonic lipid mediators
acid (minutes)
Ca 2+ Membrane
rearrangement
of receptors
7 7
Cytokine and
Ca 2+ Ca 2+ chemokine FcεRI receptor Pre-formed mediators
Nuclear production
transduction (hours) IgE Newly generated lipid mediators
Multivalent antigen Cytokines and chemokines
FiG 48.11 Simplified cartoon comparing activation and desensitization outcomes as well as a
possible explanation of how rapid desensitization works and the rearrangement of the FcεRI
receptors at the cell membrane. (From Castells et al. Hypersensitivity to antineoplastic agents:
mechanisms and treatment with rapid desensitization. Cancer Immunol Immunother. 2012; 61:
1575–84.)
