Real-time RT-PCR analysis of SI-CLP and YKL-40 expression in human macrophages. Peripheral blood–derived monocytes nonstimulated (control) or stimulated with cytokines as indicated were propagated in culture for 6 days. (A) Three representative donors with differential responsivities are presented. (Ai) IL-4, dexamethasone, and combination of both induce SI-CLP mRNA up-regulation in macrophage cultures; the lowest SI-CLP expression is detected in case of IFNγ stimulation. (Aii) IFNγ induces YKL-40 mRNA expression, whereas dexamethasone has strong inhibitory effect. (B) Effect of IFNγ (i) and IL-10 (ii) on the IL-4/Dex-induced expression of SI-CLP. Peripheral blood–derived monocytes of 6 independent donors were used for each analysis. The data were analyzed using paired 2-tailed t test. The difference was considered to be statistically significant in case of P < .05. IFNγ suppresses the effect of IL-4/Dex. IL-10 has no statistically significant effect on IL-4/Dex stimulation. The expression levels of analyzed genes were normalized to GAPDH mRNA expression. Error bars represent SD.