Thromboxane A2 Production in Allergen-Induced Immediate and Late Asthmatic Responses: Its Possible Role in Inducing the Late Response

Abstract

To determine whether thromboxane A₂ (TXA₂) participates in allergen-induced asthmatic responses, we measured plasma TXB₂ levels during allergen-induced immediate and late asthmatic responses (IAR and LAR) in atopic asthmatics. We also examined the effect of a TXA₂ synthetase inhibitor, OKY-046, on the responses.

Plasma TXB₂ levels increased in both IAR and LAR, being 2.2 times higher in LAR than in IAR. Plasma TXB₂ levels in LAR reached the peak 4 hours after allergen challenge when FEV₁ had just begun to decrease in LAR. OKY-046 inhibited both IAR and LAR with decreased plasma TXB₂ levels.

We conclude that TXA₂ is produced in allergen-induced asthmatic responses and participates in the responses, especially in inducing LAR.