Changes in expression of inhibitory and costimulatory ligands on dendritic cell subsets and regulatory T cell percentages over the course of acute sepsis. Peripheral blood was collected at enrollment and again seven days later from patients with severe sepsis and from normal controls and analyzed by flow cytometry for the presence of regulatory T cells (Treg) and dendritic cells (DC). The plasmacytoid and myeloid DC subsets were analyzed for expression of the inhibitory ligand PD-L1 or costimulatory ligand CD86 respectively. The lines connect values at enrollment and the end of study from an individual subject. Percentage and MESF values were calculated as described. P values were calculated by 2-tailed, non-parametric Wilcoxin matched pairs test. MESF, molecules of equivalent soluble fluorochrome.