The role of basophils in asthma.

The characteristics of the acute and late human response to antigen in the upper and lower airways and in the skin is summarized in TABLE 2. This table makes it clear that while mast cells are responsible for the mediator release of the acute phase, eosinophils and basophils are the cells involved in the mediator release which occurs during the experimental late phase reaction. The pattern of mediators observed during the acute response is quite characteristic of the mast cell. Thus, in the nose, skin, and lungs, the acute response is characterized by significant increases in histamine, PGD2, tryptase, and sometimes LTC4. In the late phase reaction, the pattern of mediator release is characteristic of basophils and eosinophils, and includes histamine, LTC4 (where measurable), and eosinophil-derived proteins, without PGD2 or tryptase. Basophils have been identified at appropriate time-points in each model using morphologic and phenotypic criteria, and their numbers relate to the histamine levels. Finally, treatment with glucocorticosteroids, the most potent drugs available for treating chronic allergic inflammation, obliterates the late phase reaction and decreases both mediator release and the infiltration of eosinophils and basophils. Chronic allergic inflammation is now taken by both the pulmonary and immunologic community as a hallmark of asthma, and it can be stated without equivocation that the basophils are responsible for the mediator release observed in that response.