Nasal eosinophilia and serum soluble intercellular adhesion molecule 1 in patients with allergic rhinitis treated with montelukast alone or in combination with desloratadine or levocetirizine

Background: Because intercellular adhesion molecule (ICAM) 1 and recruitment of eosinophils are crucial in supporting allergic inflammation, their down-regulation may bring additional benefits in patients' recovery. We have assessed nasal eosinophilia and serum soluble ICAM-1 (sICAM-1) concentrations in relation to nasal symptoms in patients with persistent allergic rhinitis (AR) treated for 6 weeks with either desloratadine, levocetirizine, montelukast alone, or in combination. Methods: In this single-center, randomized, double-blind, placebo-controlled, crossover, two-arm study, 40 patients with persistent AR were randomized to receive either montelukast and/or levocetirizine or placebo (n = 20) or to receive treatment with montelukast and/or desloratadine or placebo (n = 20). Nasal eosinophilia and concentration of sICAM-1 in peripheral blood were assessed before and on the last day of each treatment period. Results: All active treatments in both arms of the study resulted in the decrease of sICAM-1 and nasal eosinophilia, which correlated with the severity of nasal symptoms. In the montelukast/levocetirizine arm, montelukast decreased nasal eosinophilia more significantly than levocetirizine, whereas in reduction of sICAM-1 all active treatment options were equally effective. However, in the desloratadine/montelukast arm, the resulting improvement of combination therapy of sICAM-1 and the influx of eosinophils was not statistically significant. Conclusion: The improvement of nasal symptoms in patients with AR treated with antihistamines, with or without montelukast, may additionally result from the reduction of sICAM-1 and nasal eosinophilia. Because the combination therapy may bring inconclusive benefits in this area there is a strong need of further studies to find mechanisms that favor combination therapy.