Clinical significance of Vδ1 T cell detection in sepsis patients

This study is to investigate changes of the number of PB Vδ1 T cells and their function in patients with sepsis, analyze the clinical significance of Vδ1 T cell detection and validate the effects of Vδ1 T cells on the onset of sepsis. Forty patients with sepsis were included into this study together with forty healthy subjects who received the physical examination in the hospital during the same period, and the clinical data of all subgroups of patients with sepsis were recorded. In the morning, the fasting peripheral venous blood at 10 ml was sampled from patients with sepsis and subjects in the Health Control (HC) group. The flow cytometry (FCM) was used to measure the percentage of Vδ1 T cells in PB, analyze the correlation between the percentage of Vδ1 T cells, APACHEII score and blood lactic acid level in patients with sepsis, and detect the expression level of Foxp3 on the surface of Vδ1 T cells. CFSE staining method was used to detect the influence of Vδ1 T cells on the proliferation capacity of naïve CD4 T cells. Compared with the HC group, the number of Vδ1 T cells in PB was significantly increased in patients with sepsis (P<0.01), and the sepsis shock group exhibited the highest expression level of Vδ1 T cells, followed by the severe sepsis group and the sepsis group. The percentage of Vδ1 T cells in patients with sepsis was positively correlated with APACHEII score and the lactic acid level, respectively. Compared with the HC group, the expression level of Foxp3 on the surface of Vδ1 T cells in PB was significantly increased in patients with sepsis (P<0.01), with the highest expression level of Foxp3 in the sepsis shock group, followed by the severe sepsis group and the sepsis group. In the HC group and patients with sepsis, the proliferation rate of naïve CD4 T cells co-incubated by Vδ1 T cells and naïve CD4 T cells in PB was (66.94±8.91)% and (47.24±9.86)%, respectively. Vδ1 T cells in PB of patients with sepsis exhibited obviously increased inhibition on the proliferation of naïve CD4 T cells, indicating that PB Vδ1 T cells in patients with sepsis presented stronger immunosuppressive functions than those in the HC group (P<0.01). The percentage of PB Vδ1 T cells in patients with sepsis was increased and the immunosuppressive function was increased, so that immune function of patients with sepsis was inhibited and then sepsis occurred. This indicated that Vδ1 T cells in PB might play important roles in the immune pathogenesis of sepsis and provide clinical values in the evaluation of prognosis.