Pranlukast, a cysteinyl leukotriene antagonist, reduces serum eosinophil cationic protein levels in patients with asthma.

Cysteinyl leukotrienes (cysLTs) are considered to be important mediators involved in bronchial asthma and the ensuing eosinophilic inflammation. We evaluated the effects of pranlukast, a potent and selective cysLT receptor antagonist, on the clinical course and serum eosinophil cationic protein (ECP) levels of 10 asthmatic patients. A four-week administration of pranlukast increased the morning peak expiratory flow (PEF) (p = 0.007) and decreased as-needed beta 2-agonist use (p = 0.021). Changes in the morning PEF inversely correlated with those in the serum ECP levels (r = -0.80, p = 0.0057). These results suggest that cysLTs are important mediators involved in eosinophilic inflammation, a major pathophysiologic feature of bronchial asthma in humans.