Eosinophilic inflammation in cough variant asthma (original) (raw)

1998, European Respiratory Journal

Cough is commonly associated with wheezing and dyspnoea in symptomatic asthmatics. Wheezing is generally considered to be the sine qua non of asthma. However, it has been recognized that cough may be the sole manifestation of the disease. In 1979, CORRAO et al. [1] reported on six subjects complaining of chronic persistent cough without wheezing or dyspnoea. The subjects had no past history of asthma. They had normal baseline spirometry but bronchial hyperresponsiveness, as demonstrated with methacholine. Coughing soon disappeared after starting either oral bronchodilators, theophylline or terbutaline, but recurred when they were stopped. The authors regarded these subjects as having a variant form of asthma, which was named cough variant asthma (CVA). Several reports on CVA [2-9] followed that of CORRAO et al. [1], and the condition is now recognized as a common cause of chronic cough [4, 5]. Recent research has clarified that asthma is a chronic inflammatory airway disease, in which eosinophils play a central role: granular constituents of eosinophils are cytotoxic and cause desquamation and destruction of bronchial epithelium [10], which may lead to bronchial hyperresponsiveness [11]; lipid mediators secreted from eosinophils, such as leukotrienes C 4 , D 4 , and E 4 , and platelet activating factor, can induce bronchoconstriction, vascular permeability, and bronchial hyperresponsiveness [10]. Clinical studies in asthmatic patients have almost always demonstrated that eosinophils are increased in number and are activated in the peripheral blood, sputum, bronchoalveolar lavage (BAL) fluid, and bronchial mucosa [11-14]. Furthermore, many, although not all, studies have shown that