Background: Anaphylaxis is a life-threatening syndrome resulting from the sudden release of mast cell- and basophil-derived mediators into the circulation. However, pathological evidence of the association between inflammatory mediators and human anaphylaxis is insufficient.
Objective: The aim of this study was to better understand the relationship between in vivo production of inflammatory mediators and the pathogenesis of anaphylaxis. We also sought to evaluate mast cell activation in anaphylaxis.
Methods: We measured the concentrations of various inflammatory mediators in urine samples, which were collected from 32 anaphylactic patients during the onset of anaphylaxis and during clinical remission, 21 patients with asthma on acute exacerbation and 15 healthy control subjects. Blood and urine specimens were collected from the patients after provocation test. Urinary leukotriene E4 (LTE4), 9alpha, 11beta-prostaglandin F2 (9alpha, 11beta-PGF2), eosinophil-derived neurotoxin (EDN) and leukotriene B4 glucuronide (LTBG) concentrations were determined by enzyme immunoassay, and the activity of plasma platelet-activating factor acetylhydrolase and serum tryptase concentration were measured using commercially available kits.
Results: Significantly higher concentrations of urinary LTE4 and 9alpha, 11beta-PGF2, which immediately decreased during clinical remission, were observed in the anaphylactic patients than in asthmatic patients on acute exacerbation and healthy control subjects. Concentrations of EDN and LTBG were not significantly different among the anaphylactic patients, asthmatic patients on acute exacerbation and healthy subjects. There was a significant correlation between urinary LTE4 and 9alpha, 11beta-PGF2 concentrations in the anaphylactic patients (r=0.672, P=0.005, n=32). In addition, LTE4 concentration in patients with anaphylactic shock is significantly elevated compared with that in patients without anaphylactic shock.
Conclusions: This is a report on the significant increase in urinary LTE4 and 9alpha, 11beta-PGF2 concentrations during anaphylaxis. Urinary LTE4 and 9alpha, 11beta-PGF2 concentrations may be a reliable marker of endogenous production of inflammatory mediators associated with anaphylaxis.