Dexamethasone (Dex), but not MMF or CsA, interferes with mTOR inhibition. PBMCs treated with the indicated concentrations of (A) Dex, (B) MMF, or (C) CsA for 30 minutes were incubated with 100nM rapamycin (Rap) or medium and then stimulated with 100 ng/mL LPS. IL-12p40 and IL-10 in cell-free supernatants were assessed after 20 hours. Data are mean ± SEM of 5 independent experiments. *P < .05. **P < .01. n.s. indicates not significant. (D) PBMCs were treated with 25nM Dex and/or 100nM Rap and then stimulated with 10 μg/mL OKT-3 as indicated. IFN-γ and IL-2 were determined in the supernatant after 24 hours. Data are mean ± SEM of 3 independent experiments. *P < .05. (E) T cells were stimulated with 10 μg/mL OKT-3 and 100nM Rap and/or 25nM Dex as indicated. Proliferation was measured on days 2 and 3 and is expressed as the means of triplicates of 2 independent donors.