IGE+ CELLS IN THE PERIPHERAL-BLOOD OF ATOPIC, NONATOPIC, AND BEE VENOM-HYPERSENSITIVE INDIVIDUALS EXHIBIT THE PHENOTYPE OF HIGHLY DIFFERENTIATED B-CELLS

We have analyzed IgE(+) cells in peripheral blood of atopic donors, donors hypersensitive to bee venom, and nonatopic control donors with two- and three-color flow cytometry. Although the percentage of IgE(+) cells varied among these groups, the overall phenotypic patterns were similar. Most IgE(+) cells do not display typical B-cell markers, such as CD19, CD20, and CD21. A significant proportion of these cells stain for CD38, indicating that they are more differentiated. IgE(+) cells express Fc gamma RII and CD45RO, an isoform associated with an advanced level of differentiation The majority of IgE(+) cells do nor coexpress other surface immunoglobulin isotypes. In the case of bee venom-hypersensitive donors, we have been able to identify a small population of IgE(+) cells with a specificity for phospholipase A2 a major immunogenic component of bee venom. The phospholipase A2(+) cells display a phenotype similar to that of the IgE(+) cells.