Modulation of HLA-DR expression on CD14HIGH and CD14LOW monocytes. Modulation of HLA-DR expression on CD14HIGH and CD14LOW monocytes by different PAMPs in the absence or presence of IL-10 and/or hydrocortisone. Blood samples from healthy donors were incubated for 24 hours without or with Pam3CysSK4 (100 ng/ml), muramyl dipeptide (MDP, 100 nM) or Escherichia coli LPS (100 ng/ml) in the absence or presence of IL-10 (10 ng/ml) and/or hydrocortisone (HC, 100 μM). For both subpopulations, the results are expressed as the percent change of mean fluorescence intensity compared to HLA-DR measured in untreated cells (control). The results are the mean ± SEM of four independent experiments with different donors. *P < 0.05, comparison between control and PAMPs --induced modulation. +P < 0.05, comparison between PAMPs alone and PAMPs + IL-10 and/or HC.