Changes of peripheral blood Vδ1 T cells in patients with atherosclerotic cerebral infarction

To observe the ratio of peripheral blood Vδ1 T cells in patients with atherosclerotic cerebral infarction (ACI) and their function changes, and preliminarily explore the mechanism of change in ratio of peripheral blood Vδ1 T cells in ACI patients. 30 ACI patients enrolled in the neurology department in our hospital from January 2016 to December 2016 were selected, and 30 healthy subjects enrolled in the hospital during the same period were selected as healthy controls. Peripheral blood mononuclear cells (PBMC) were obtained by density gradient centrifugation. The ratio of Vδ1 T cells in peripheral blood of ACI patients was detected by flow cytometry, and the correlations between the ratio of Vδ1 T cells and the neurological deficits and infarction size in ACI patients were analyzed. A high proportion of Vδ1 T cells were obtained by in vitro amplification, and high-purity Vδ1 T cells and Naïve CD4 T cells were obtained by flow cytometry and magnetic bead sorting respectively. The effect of Vδ1 T cells on the proliferation of Naïve CD4 T cells and the secretion of IFN-γ were investigated by CFSE staining method; the correlation between the ratio of Vδ1 T cells in peripheral blood and the Ox-LDL level in peripheral blood of ACI patients was analyzed. The Vδ1 T cells in peripheral blood were treated by Ox-LDL, and the effect of Ox-LDL on Vδ1 T cell apoptosis was determined by apoptosis staining method. Compared with the healthy control group, the ratio of Vδ1 T cells in peripheral blood of ACI patients was significantly decreased (P<0.0001). The ratio of Vδ1 T cells in peripheral blood of ACI patients was not significantly correlated with age, sex, hypertension, diabetes and dyslipidemia (P>0.05). However, with the gradual aggravation of neurological deficit and gradual increase of infarct volume, the ratio of Vδ1 T cells in peripheral blood of ACI patients decreased gradually. Besides, the functional studies showed that the immunosuppressive functions of Vδ1 T cells in peripheral blood of ACI patients were also significantly decreased (P<0.0001). The ratio of Vδ1 T cells in peripheral blood of ACI patients was negatively correlated with the Ox-LDL level in peripheral blood (r²=0.1691; P=0.0240); the Ox-LDL treatment of Vδ1 T cells induced apoptosis of Vδ1 T cells, and with the increased Ox-LDL concentration, the ratio of Vδ1 T cell apoptosis gradually increased. The decreased ratio of Vδ1 T cells in peripheral blood and loss of functions in ACI patients lead to the occurrence of immunoinflammatory reactions, which may be one of the possible causes of ACI. In addition, this study also showed that, Ox-LDL could induce Vδ1 T cell apoptosis and lead to decrease in ratio of Vδ1 T cells in peripheral blood, which may be one of the reasons for decreased ratio of Vδ1 T cells in peripheral blood of ACI patients. In summary, this study can further help the understanding of the pathogenesis of ACI.