in regulatory T cells among patients with sepsis

patients (n = 182) were selected as sepsis group and divided into three subgroups: mild sepsis group, severe sepsis group and septic shock group; 185 healthy volunteers were enrolled as control group. Flow cytometry and blood rou-tine examination were performed for T lymphocytes and surface co-stimulatory molecules expressions. Pearson cor-relation test was applied for the correlation of co-stimulatory molecules expressions on T lymphocytes with critical illness in sepsis. Logistic regression analysis was conducted for risk factors in sepsis. Results: Heart rate and WBC in subgroups were higher than control group (P < 0.05). The differences in APACHE II, SAP II and SOFA score among subgroups were statistically significant (P < 0.05). Compared with control group, lymphocyte ratio and percentage of CD4+ T cells reduced in subgroups (P < 0.05). The differences in expression levels of CD4+PD-1+, CD8+PD-1+, and CD8+CTLA-4+ showed statistical significances (P < 0.05). Apparently, expression levels of CD4+TIM-3+, CD8+TIM-3+, CD4+PD-1+, CD8+PD-1+, and CD4+CTLA-4+ were positively correlated with APACHE II score (all P < 0.05). Logistic regression analysis showed that heart rate and expression level of CD4+PD-1+ might be risk factors while the per-centage of CD4+ T cells might be a protective factor for sepsis (P < 0.05). Conclusion: PD-1 aggravates immune responses consistent with promotion of T cell exhaustion in sepsis. Expression level of CD4+PD-1+ and heart rate ar