The Expression of Programmed Death-1 on CD4+ and CD8+ T Lymphocytes in Patients with Type 2 Diabetes and Severe Sepsis

OBJECTIVE To investigate the expression of Programmed death-1 (PD-1) on T lymphocytes in patients with type 2 diabetes mellitus (T2DM) and severe sepsis, we determined PD-1 expression on CD4+ and CD8+ T lymphocytes of patients with T2DM, severe sepsis, and T2DM combined with severe sepsis. RESEARCH DESIGN AND METHODS This prospective and observational study included 50 healthy controls, 80 cases of T2DM without infection (T2DM group), 88 cases of severe sepsis without T2DM (SS group), and 77 cases of severe sepsis combined with T2DM (SS+T2DM group). Expression of peripheral blood PD-1+ CD4+ T cells and PD-1+ CD8+ T cells were compared between these 4 groups. Then, 28-day survival of the SS and SS+T2DM patients was assessed, and the expression of PD-1 on T cells was also compared between survivors and non-survivors. RESULTS Percentages of PD-1+ CD4+ T cells and PD-1+ CD8+ T cells were higher in the T2DM group than in the healthy control group, and were highest in the SS and SS+T2DM groups. However, the expression of PD-1 on T cells and the mortality showed no significant difference between the SS and SS+T2DM groups. The expression of PD-1 on T cells was higher in non-survivors than survivors, but within the survivor group or non-survivor group, no difference can be detected between those with T2DM and those without T2DM. CONCLUSION The expression of PD-1 on T cells was increased in both T2DM and severe septic patients, but combining T2DM did not cause a further increase on the PD-1 expression in patients with severe sepsis.