Asthma may represent the clinical manifestations of a unique form of chronic airway inflammation and is often associated with allergy. To better define the components of allergic inflammation in the lung, fluids obtained by bronchoalveolar lavage (BAL) were examined for cells, inflammatory mediators, and markers of airway permeability 5 min and 19 h following instillation of ragweed antigen directly into an airway segment of allergic asthmatic subjects. The 5-min response to antigen challenge (n = 10) was characterized by 17- to 208-fold increases in histamine, prostaglandin D2 (PGD2), and its metabolite, 9 alpha,11 beta-PGF2, thromboxane B2, and 6-keto-PGF1 alpha compared with a saline-challenged segment (0.004 less than p less than 0.017). The increases in most of these mediators were significantly correlated with each other (0.0001 less than p less than or equal to 0.01), and the magnitude of all significant mediator increases was directly correlated with skin test sensitivity to ragweed antigen (0.007 less than or equal to p less than or equal to 0.05). There was also a slight increase in kinins (p = 0.04). Changes in cells and airway permeability were not detected. In contrast, the 19-h response to antigen challenge (n = 9) was characterized by a 13-fold increase in total cells recovered by BAL. Eosinophils, basophils, and lymphocytes were significantly increased and comprised 38, 1, and 9% of total cells, respectively. A neutrophil influx was also observed but was not specific for antigen challenge since a similar change was observed in a sham, saline-challenged site.(ABSTRACT TRUNCATED AT 250 WORDS)