Impact of Hymenoptera venom allergy and the effects of specific venom immunotherapy on mast cell metabolites in sensitized children

Introduction and objective. Mast cells (MC) are effector cells during severe systemic reactions (SR) to Hymenoptera stings. Venom specific immunotherapy (VIT) is the treatment of choice for prevention of SR to stings. Tryptase and prostaglandin D2 metabolites (PGD2 ) are the markers of MC activation. The study design was to 1. compare baseline values of serum tryptase concentration (BST) and PGD2 metabolites in children with/without venom sensitization, 2. to evaluate an influence of rush VIT on MC markers in treated children. Materials and methods. Sensitized group: 25 children with SR to Hymenoptera sting. Control group: 19 healthy children. Active treatment: 5-day-rush-VIT. BST was evaluated by ImmunoCAP, PGD2 metabolites in blood and urine by GC-NICI-MS. Results. The baseline blood levels of MC markers were significantly higher, while urinary concentration of 9α,11β-PGF2 was significantly lower in the whole group of venom-sensitized children compared to controls. Severity of SR showed negative correlation with urinary PGD2 metabolites, while positive with plasma 9α,11β-PGF2 and BST concentration The highest sensitivity was obtained for plasma 9α,11β-PGF2 whereas the highest specificity for urinary PGD-M. Conclusions. In children with IgE-mediated SR to Hymenoptera stings, elevation of baseline values of PGD2 metabolites in blood is accompanied by decreased excretion of its urinary metabolites. Assessment of stable PGD2 metabolites might serve as an independent MC marker to identify allergic children. There is an association between urinary PGD2 metabolites and severity of the SR to Hymenoptera stings.