Expression of sCD23 in atopic and nonatopic blood donors: correlation with age, total serum IgE, and allergic symptoms

Although structure, biologic activities, and expression of the low‐affinity IgE receptor (Fc_eRII, CD23) have been investigated, the diagnostic value for allergies of this molecule and its soluble circulating fragment (sCD23) remains unclear. Therefore, serum sCD23 levels were measured in 203 blood donors. They were divided into atopic and nonatopic subjects by allergy history, physical findings of allergic symptoms, and corresponding specific circulating IgE antibodies. The group consisting of nonatopic subjects was divided into four age categories in order to exclude age‐dependent variations in the expression of the low‐affinity IgE receptor. In our study population, sCD23 serum levels were not influenced by age. Furthermore, no significant differences, especially no decrease in serum sCD23 levels, between the four nonatopic age groups were detected. There was no significant increase of sCD23 serum levels in atopic subjects in comparison with nonatopic blood donors. In addition, no correlation between total IgE levels and sCD23 serum levels could be detected, in either the group of atopic donors or the group of nonatopics. Our data suggest that the circulating low‐affinity IgE receptor does not appear to be an additional general marker for the diagnosis of allergies, as previously suggested.