Montelukast inhibits interleukin-5 mRNA expression and cysteinyl leukotriene production in ragweed and mite-stimulated peripheral blood mononuclear cells from patients with asthma.

Important in the pathogenesis of asthma is the secretion of interleukin (IL)-5 by allergen-specific TH2 cells, which augments eosinophil functions, as well as subsequent synthesis of cysteinyl leukotrienes (CysLTs). Montelukast is an inhibitor of CysLT and also has been shown to decrease eosinophil counts in peripheral blood and sputum of patients with asthma. This study was performed to investigate the in vitro effects of montelukast, a leukotriene receptor antagonist, on CysLTs and IL-5 production and expression by peripheral blood mononuclear cells (PBMCs) stimulated with ragweed (RW) and mite (M) allergens.