Hypersensisitivity Type I: LATE RESPONSE.
Immediate (minutes): antigen crosslinks preformed IgE on presensitized mast cells
immediate degranulation > release of histamine (a vasoactive amine) and tryptase (a marker of mast cell activation).
Late (hours): chemokines (attract inflammatory cells, eg, eosinophils) and other mediators (eg, leukotrienes) from mast cells > inflammation and tissue damage.
FA 2020 P 112
(FA 2020 Pg 214)
Acute inflammation + Vasodilation of vasculature and increased endothelial permeability. IL1, IL6, and TNFa are all involved in acute inflammation.
This (late bee sting rxn) is describing an Arthus reaction (localized Type III HSR) + IgG immune complexes accumulate at site --> mast cell degranulation --> Neutrophil recruitment + IgG immune complexes also stimulate macrophages to release inflammatory cytokines (IL-1, IL-6, TNF-a) and chemokines (IL-8) --> Neutrophil recruitment result in edematous indurated lesion
Timeline for arthus reaction bee sting: 1-8 hours, generally: 6-12 hours vs Late phase Type 1 HSR 2-4 hours