Unilateral nasal allergen challenge leads to bilateral release of prostaglandin D₂

Background. Multiple mediators including prostaglandin D₂ and leukotriene B₄ have been shown to increase in nasal secretions during the early response to nasal challenge with antigen. Objective. Our objective was to investigate the time course of prostanoid and leukotriene B₄ release into nasal secretions on both the ipsilateral and contralateral side after a unilateral nasal allergen challenge. Methods. We performed a controlled, randomized trial. Six volunteers were challenged unilaterally with antigen or diluent in a randomized order and discs were used to collect nasal secretions from both nostrils at 2 min intervals for 20 min after the challenge. Prostanoids and leukotriene B₄ (LTB₄) in recovered nasal secretions were measured by combined capillary gas chromatography-negative ion chemical ionization mass spectrometry (GC/MS). Results. Nasal allergen challenge resulted in a significant and immediate increase in symptoms and sneezing. PGD₂ was significantly elevated above diluent values (0.6 ± 0.6 pg) 30 s after removal of the allergen disc (P < 0.05), reached its peak (423.2 ± 182.4 pg) at 2 min and then slowly decreased. PGD₂ also increased on the contralateral side after unilateral allergen challenge, reaching peak values about six times lower than on the ipsilateral side (70.8 ± 21.7 pg at 6 min). Levels of 9a, 11b-PGF₂ after antigen provocation became significantly higher than after diluent (0 ± 0 pg) on the ipsilateral side at 2 min (17.2 ± 5.9 pg), and reached peak levels at 4 min (25.1 ± 8.0 pg). LTB₄ also increased significantly on the side of challenge. For the other prostanoids measured (PGF₂, PGF(2α), TxB₂, 6kPGF(1α)), no significant changes in either ipsilateral or contralateral secretions were observed after allergen challenge. Conclusions. Our study described the kinetics of PGD₂ and LTB₄ release as well as the contralateral release of PGD₂.