Reduced IFNγ production in response to IL‐12 stimulation and/or reduced IL‐12 production in atopic patients

Abstract

Background Several studies have shown that interleukin (IL)‐4 and interferon‐gamma (IFNγ) are important for the regulation of IgE production and that IL‐12 induces IFNγ. Objective IFNγ production in response to IL‐12 stimulation and IL‐12 production were investigated in peripheral blood mononuclear cells (PBMCs) of atopic patients with various levels of serum IgE. Methods Cytokine production from PBMCs was measured following stimulation with a nonspecific stimulator (phytohemagglutinin: PHA), a specific stimulator (Der f 1) and IL‐12 in 17 healthy controls and 23 atopic patients with various serum IgE levels. Results The IFNγ production by IL‐12‐stimulated PBMCs in the atopic group was lower than that in the control group. Furthermore, the serum IgE level was negatively correlated with IFNγ production by PBMCs stimulated with IL‐12 (P < 0.001), and with IL‐12 production by PBMCs stimulated with Der f 1 (P < 0.001). Although the IFNγ concentrations by PHA‐stimulated PBMCs were correlated with those by IL‐12‐stimulated PBMCs, there were differences in several patients. Conclusions Our results indicated that atopic patients may have some abnormality in the IL‐12‐IFNγ loop. It was shown that the elevation in IgE levels in atopic patients may be due to reduced IFNγ production in response to IL‐12 stimulation and/or due to reduced IL‐12 production.