Hydrocortisone enhances allergen-specific IgE production by peripheral blood mononuclear cells from atopic patients with high serum allergen-specificIgE levels

Background Although there is convincing evidence that human B cells can be induced to produce IgE by a combination of interleukin 4 (IL-4) and hydroco rtisone (HC) in atopic subjects, it is still uncertain if this performs the same functions in allergen-specific IgE synthesis. Objective This study was designed to investigate the differences of IgE reg ulation between atopics and nonatopics, interactions of HC with IL-4, and t he correlation between in vitro total IgE, allergen-specific IgE synthesis and serum IgE levels. Methods Peripheral blood mononuclear cells (PBMCs) from 16 atopic asthma pa tients sensitive to Dermatophagoides farinae and seven nonatopic controls w ere cultured with IL-4 and/or HC. Total IgE and D. farinae-specific IgE in culture supernatant were measured by ELISA and FAST. Results IL-4 increased total IgE synthesis in PBMCs from both atopics and n onatopics, whereas, HC had this effect only in some atopics who showed spon taneous IgE production in vitro. HC acted synergistically with IL-4 in tota l IgE synthesis, Their effects were more remarkable in cases with lower tot al serum IgE levels. PBMCs from eight of 16 atopics produced D. farinae-spe cific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more p rofound 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. farinae-specific IgE synthesis by PBMC s from nonatopics. Conclusion HC had a more profound effect than IL-4 on the induction of D. f arinae-specific IgE synthesis in atopic patients with high serum allergen s pecific IgE levels, Further studies to determine the causes of these effect s, such as the presence of long lived allergen specific B cells as the resu lt of the priming effect of IL-4 in vivo, may be needed.