Presence of bronchoalveolar lavage fluid necessary for platelet activating factor-induced ciliary depression.

Many different mediators have been implicated in allergic responses and allergic diseases of the respiratory tract. The influence of several allergic inflammatory mediators on the ciliary activity has been well studied. However, ciliary responsiveness to platelet-activating factor (PAF) is yet to be established conclusively. Our study concerns the response of normal tracheal cilia from the guinea pig during an in vitro contact with PAF. PAF at concentrations between 10(-10) and 10(-8) M never affected the ciliary activity. On the other hand, such concentrations of PAF inhibited the ciliary activity in a dose-response fashion within 5 min in the presence of alveolar macrophages. Such a ciliary dysfunction should allow allergens and other molecules to easily invade epithelium and submucosa of the airway, resulting in an increased epithelial permeability which might be a mild manifestation of airway hyperresponsiveness and make a significant contribution to further airway hyperresponsiveness.