mRNA expression analysis of seven genes after incubation with recombinant IFN-γ in the ex vivo model of endotoxin tolerance. mRNA expressions of (a) TNF-α, (b) IL-10, (c) HLA-DRA, (d) CIITA, (e) IRAK-M, (f) ABIN-3 and (g) LY64 were quantified by quantitative RT-PCR in peripheral blood mononuclear cells (PBMCs) from 10 healthy volunteers after induction of endotoxin tolerance. Black columns represent controls (cells without any lipopolysaccharide (LPS) stimulation), white columns indicate LPS-unprimed cells (only stimulated once with 100 ng/ml LPS) and dark grey columns show LPS-primed cells (two LPS stimulations: 2 ng/ml followed by 100 ng/ml) and light grey show LPS-primed cells incubated with rIFN-γ1b (100 ng/ml). Gene expression results are presented as a normalized ratio vs data obtained in unstimulated cells (fold changes vs control). Data are presented as mean ± standard deviation. The Wilcoxon signed rank test was used to test for statistical significance († P < 0.005 vs LPS-unprimed cells; ** P < 0.005 vs vehicle). IFN, interferon.