Mediators and allergic inflammation of human airways

Local antigen challenge in patients with respiratory allergy is associated with histamine and arachidonic acid metabolites release, both in upper and in lower respiratory airways. Raised histamine levels can be detected in nasal secretions 5 min after allergen stimulation. Increased leukotriene C4 and prostaglandin D2 concentrations persist for a longer period (respectively 20 and 30 min). Endobronchial antigen stimulation is also followed by release of histamine, leukotriene C4 and prostaglandin D2, which can be detected in bronchial lavage fluid. Elevated concentrations of these mediators can be found 5 and 15 min after challenge. Moreover, endobronchial antigen stimulation is associated with an increase in the number of bronchial epithelial cells recovered in bronchial lavage fluids.