Background : Although the basic cellular and molecular requirements for the induction and synthesis of whole human IgE antibody have extensively been investigated, the mechanisms involved in the regulation of allergen-specific IgE synthesis are not ye...
Background : Although the basic cellular and molecular requirements for the induction and synthesis of whole human IgE antibody have extensively been investigated, the mechanisms involved in the regulation of allergen-specific IgE synthesis are not yet fully understood. Objectives : The aims of this study were to elucidate the differences in the total and specific IgE regulation by hydrocortisone(HC) with interleukin 4 (IL-4) between atopics and non-atopics and to determine the relationship between in vitro IgE synthesis and serum IgE levels. Methods : Peripheral blood mononuclear cells(PBMCs) from sixteen atopic asthma patients sensitive to Dermatophagoides farinae(D.f) and seven non-atopics were cultured with IL-4 and/or HC. Total and D.f-specific IgE in culture supernatant were measured using ELISA and FAST methods respectively. Results : PBMCs from 8 of 16 atopics produced D.f-specific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more profound effects than IL-4 in these patients. They also showed higher total IgE synthesis by HC, and higher specific serum IgE levels than the others. IL-4 and/or HC did not induce any D.f-specific IgE synthesis by PBMCs from non-atopics. Conclusion : These data suggest that atopic patients have allergen-specific B cells that have already been switched to IgE production, probably due to in vivo priming effect of IL-4. (J Asthma Allergy Clin Immunol 21: 21-27, 2001)