CysLT1-R expression following allergen provocation in asthma and allergic rhinitis.

Cysteinyl leukotrienes (CysLTs) contribute to allergic and inflammatory diseases through CysLT(1)-R. We aimed to assess CysLT(1)-R mRNA expression in induced sputum of rhinitics with or without asthma before and following allergen challenges. Both groups underwent nasal and "low dose" lung allergen challenges. Asthmatics also underwent "standard" lung challenge. Sputum was obtained before and at different time-points following the challenges for CysLT(1)-R, 5-lipoxygenase (5-LO), and eotaxin mRNA assessments. At baseline, there was no difference in mediator levels between groups. An increase in CysLT(1)-R mRNA (p=0.04) and a trend towards an increase in 5-LO and eotaxin (p=0.06 for both) at 24 h post-nasal challenge were observed. Following "low dose" lung allergen challenge, there was a trend towards an increase in CysLT(1)-R (p=0.07). In conclusion, CysLT(1)-R gene expression changes can be detected in sputum following allergen challenges. No difference was observed between groups, suggesting that changes in CysLT(1)-R expression occur whether or not the subject has concurrent asthma.