IFN-gamma plays a dominant role in upregulation of Candida-specific IgE synthesis in patients with atopic dermatitis

Background: Although Candida albicans (CA) is known to induce Th 1 clones t hat suppress IgE synthesis, serum IgE antibody against CA is often increase d in atopic patients. This study aims to elucidate the mechanism of IgE syn thesis against CA in atopic patients. Methods: We measured the production o f IL-4 and IFN-gamma by peripheral blood mononuclear cells (PBMCs) from ato pic patients upon stimulation with CA and examined the correlation with the level of serum IgE antibody against CA. Results: The level of serum CA-spe cific IgE antibody (CA-ISE) was significantly higher in patients with atopi c dermatitis (AD) than in patients with bronchial asthma (BA) (geometric me an = 3.6 vs. 0.27 U-A/ml, p< 0.02) (U-A = unit allergen), while there was n o difference in the level of house dust mite-specific IgE antibody between them (67.6 vs. 87.1 U-A/ml). Although IL-4 production by PBMCs upon stimula tion with CA in patients with AD was not significantly different from that in patients with BA (mean = 359.1 vs. 515.3 fg/ml), lFN-gamma production wa s significantly lower in the former than in the latter group (8.1 vs. 56.2 pg/ml, p < 0.001). Consequently, the ratio of IL-4/IFN-gamma production was apparently higher in patients with AD than in those with BA, which corresp onds to the difference between them in the level of serum CA-IgE. A signifi cant negative correlation was seen in patients with AD between IFN-gamma pr oduction by CA-stimulated PBMCs and the level of serum CA-IgE (p < 0.05), C onclusions: IgE synthesis against CA in atopic patients may be precipitated not by enhancing IL-4 production, but by reducing IFN-gamma secretion. Cop yright (C) 2000 S. Karger AG, Basel.