[Leukotriene modifiers]

Cysteinyl leukotriene (CysLT) C4, D4, and E4 play key roles in asthma. CysLTs are newly generated after cellular activation and are produced by eosinophils, mast cells, alveolar macrophages, and neutrophils. Pharmacological actions of CysLTs include potent bronchoconstriction, increased microvascular leakage and mucus secretion, chemoattraction of eosinophils, acceleration of eosinophil apoptosis, and proliferation of human airway smooth muscle. Recent studies demonstrated that CysLT1 receptors are distributed on CD34+ stem cells, eosinophils, monocytes, macrophages, basophils, and B cells in addition to airway smooth muscle. Because of these wide variety of distribution, Cys LTs may have another important roles in airway inflammation. CysLT1 receptor antagonist is widely used and found to be beneficial for the chronic management of asthma especially to symptomatic patients who had already been treated with moderate to high doses of inhaled corticosteroids and also to mild to moderate steroid-naive asthmatic patients.