Flow cytometric expression of PD-1 and PD-L1.

<p>PD-1 was increased in patients with sepsis attributed to Multidrug Resistant (MDR) bacteria compared to Critically-Ill Non-Septic (CINS) patients on both CD4 and CD8 T cells, both in the percentage of cells bearing the receptor (a; % cells positive) and the intensity of staining (b; GMFI). GMFI = geo mean fluorescence intensity. Surface PD-L1 on monocytes showed increased staining intensity (d), however, there was insufficient evidence of a significant increase in the percentage of PD-L1 positive monocytes (c). Bars represent mean +/- S.E.M. *<i>p</i><0.05, ** p<0.01, ***<i>p</i><0.001.