Evaluation of eicosanoids in nasal lavage as biomarkers of inflammation in patients with allergic rhinitis

Introduction

Cysteinyl leukotrienes (cys-LTs), 8-isoprostane and prostaglandin E2 (PGE₂) constitute fundamental mediators in allergic inflammation; therefore we wanted to determine the utility of PGE₂, 8-isoprostane and cys-LT levels in nasal lavage as biomarkers of allergic inflammation.

Material and methods

Twenty-one patients with allergic rhinitis (AR) were included on the basis of a positive history of AR symptoms and positive results of skin prick tests to grass pollen allergens. The main exclusion criteria were: uncontrolled asthma, nasal polyps, respiratory infection, tuberculosis, neoplastic and autoimmune diseases, current smoking and immunotherapy. Both outside the pollen season and at the height of the pollen season, total nasal symptom score (TNS-4) was evaluated and the levels of cys-LTs, 8-isoprostane and PGE₂ were measured in nasal lavage fluid (NALF).

Results

Natural allergen stimulation resulted in a significant increase of TNS-4 (p < 0.001) and nasal eosinophilia (p < 0.001). The concentration of PGE₂ dominated in the NALF outside the pollen season and decreased significantly at the height of natural exposure (p < 0.01). In contrast, lower baseline concentrations of cys-LTs and 8-isoprostane increased significantly upon allergen stimulation (p < 0.05). There was a significant correlation between mean concentration of PGE₂ and eosinophil number in NALF (r = 0.67, p = 0.0439).

Conclusions

The NALF concentrations of cys-LTs and 8-isoprostane change simultaneously with TNS-4 and nasal eosinophilia. However, due to the lack of any significant correlation, their utility as markers of allergic rhinitis should be warily considered. The decrease of PGE₂ concentration in NALF which correlated with nasal eosinophilia may participate in escalation of allergic inflammation and needs further evaluation.