Eosinophils recruited to the lung by segmental antigen challenge show a reduced chemotactic response to leukotriene...

Inflammatory cells, particularly eosinophils, are thought to be important in allergic airway disease. However, the mechanisms responsible for their recruitment to the lung have not been well established in humans, in vivo. In this report we demonstrate that eosinophils recruited to the lung of ragweed allergic volunteers by segmental antigen challenge have a decreased chemotactic response to leukotriene (LT) B4 ex vivo, in comparison with eosinophils isolated from peripheral blood (80% inhibition at 10(-8) M LTB4, the optimal concentration, p < 0.01). Their chemotactic response to formyl-methionyl-leucyl-phenylalanine (FMLP) was normal. Although the response to platelet activating factor also appeared to be reduced, this reduction was not statistically significant. These data suggest that lung eosinophils were exposed to LTB4 in vivo and are consistent with the hypothesis that LTB4 is important in the recruitment of eosinophils to the lung during IgE-mediated reactions in the lung in humans.