| IgE
Full Name: Immunoglobulin E
Definition:
IgE is an antibody isotype involved primarily in allergic immune responses and
defense against certain parasites. IgE binds with high affinity to FcεRI
receptors on mast cells and basophils.
Asthma relevance:
IgE is a major mediator and biomarker of allergic asthma. Allergen-specific IgE
binds FcεRI on mast cells and basophils. Subsequent allergen-mediated
cross-linking triggers cellular activation and release of histamine,
leukotrienes, prostaglandins, and inflammatory cytokines.
Elevated total or allergen-specific IgE is frequently measured in human asthma
and in experimental allergic asthma models such as ovalbumin (OVA) and house
dust mite (HDM) models.
Direction:
IgE ↑ = generally adverse in allergic asthma
IgE ↓ = generally beneficial when elevated as part of an allergic response
Common measurement contexts:
Serum total IgE; plasma IgE; allergen-specific IgE; OVA-specific IgE;
HDM-specific IgE
Typical pathway:
IL-4 / IL-13 ↑
→ B-cell class switching ↑
→ IgE ↑
→ FcεRI activation ↑
→ mast-cell / basophil degranulation ↑
→ histamine + leukotrienes ↑
→ bronchoconstriction and airway inflammation ↑
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