The mTOR pathway regulates inflammatory cytokine production in human monocytes in vitro and in transplant patients ex vivo. (A) Human monocytes obtained from healthy subjects were preincubated with rapamycin (Rap; 1, 10, or 100nM) as indicated and stimulated with 100 ng/mL LPS. IL-12p40, IL-10, and TNF-α in cell-free supernatants were determined after LPS stimulation for 20 hours. For measurement of IL-12p70 production, monocytes were additionally stimulated with 30 ng/mL IFN-γ. Data are mean ± SEM for 3 donors. (B) Whole blood from kidney transplant patients receiving CsA, FK506, or Rap was left untreated or stimulated with 1 μg/mL LPS for 20 hours. IL-12p40, IL-10, IL-6, TNF-α, and IL-1β in cell-free supernatants were determined by Luminex assays. Data are mean ± SEM of 21 (CsA), 28 (FK506), or 19 (Rap) donors. *P < .05. **P < .01. n.d. indicates not determined. (C) Correlation analysis of IL-12p40 production versus prednisone dose in the patients from panel B.