HIGH-AFFINITY IGE RECEPTOR (FC-EPSILON-RI) EXPRESSION ON EOSINOPHILS INFILTRATING THE LESIONS AND MITE PATCH TESTED SITES IN ATOPIC DERMATITIS

Expression of the high affinity IgE receptor (Fc epsilon RI) on eosino phils has recently been reported. This led us to evaluate Fc epsilon R I expression on eosinophils in atopic dermatitis (AD). Double immunofl uorescence stainings with an anti-Fc epsilon RI monoclonal antibody (m Ab) and a polyclonal antieosinophil cationic protein (ECP) antibody we re performed on lesional biopsy specimens from patients with AD and fr om patients with bullous pemphigoid (BP) as controls. In AD and BP les ions, 77% and 70% of eosinophils expressed Fc epsilon RI, respectively . However, the intensity of Fc epsilon RI staining in AD was much stro nger than in BP, suggesting upregulation of Fc epsilon RI expression o n eosinophils in AD. In addition, the eosinophils infiltrating AD lesi ons were stained strongly with anti-CD23 mAb and anti-IgE antibody. At the sites of mite patch testing in AD, Fc epsilon RI-, CD23- and IgE- positive eosinophils mere observed to the same degree as in the lesion s, and a considerable number of mite antigen-bearing eosinophils were detected. Fc epsilon RI and CD23 were both upregulated on the skin-inf iltrating eosinophils in AD and bound IgE molecules.