Increased expression of Fc epsilon R2/CD23 on peripheral blood B lymphocytes and serum IgE levels in Kawasaki disease.

We analyzed the expression of Fc epsilon R2/CD23 on the peripheral blood B lymphocytes of 10 patients with Kawasaki disease (KD) using a fluorescence-activated cell sorter. The absolute count of CD23-positive B lymphocytes and the ratio of CD23-positive B lymphocytes to B lymphocytes were high during the acute stage of KD in comparison to those during the convalescent stage and in control subjects. In addition, both the increased number of CD23-positive B lymphocytes and the increased serum IgE levels appeared during the latter part of the acute stage. These results suggest that the increased number of CD23-positive B lymphocytes during the latter part of the acute stage in KD reflect the activation of B lymphocytes and have an important role in IgE-mediated immunity.