ANTI-IGE-INDUCED ACCUMULATION OF LEUKOCYTES, MEDIATORS, AND ALBUMIN IN SKIN CHAMBER FLUID FROM HEALTHY AND ATOPIC SUBJECTS

The aim of this study ws to examine potential differences between heal thy and atopic subjects with regard to IgE-mediated cutaneous inflamma tion. For this purpose, we analyzed histamine, tryptase, leukotriene B -4, albumin, eosinophils, and total leukocytes in skin chamber fluid a fter challenge with anti-human IgE. We also measured gross skin reacti vity (wheal, flare, and late-phase reactions), circulating IgE, and eo sinophils, as well as the state of eosinophil activation. It was found that despite having more circulating IgE, the skin responsiveness of the atopic subjects did not differ significantly from that of the nona topic subjects with respect to mediator release, albumin extravasation , or total recruitment of leukocytes. Moreover, the sizes of anti-IgE- induced wheal, flare, and late-phase reactions were very similar in th e two groups. On the other hand, significant recruitment of eosinophil s during the IgE-mediated reaction was more or less restricted to the atopic group. Yet the recruited eosinophils, of which the majority was in an early state of activation before degranulation, did not seem to contribute significantly to the IgE-mediated delayed skin edema. Furt hermore, the eosinophil count in anti-IgE chambers of the atopic subje cts did not correlate with any of the other parameters monitored. Thus because the anti-IgE-induced recruitment of eosinophils appeared to b e unrelated to factors such as the number of peripheral blood eosinoph ils, the degree of mast cell activation, the intensity of inflammatory skin changes, and the level of circulating IgE, it is apparent that t he mechanisms for and pathophysiologic role of IgE-mediated dermal eos inophil accumulation in atopic subjects require further investigation.