The expressions of CTLA-4 and PD-1 on CD(4)(+) T cells and the level of plasma VEGF in patients with obstructive sleep apnea hypopnea syndrome

Abstract

Objective: CD(4)(+)T cells, cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death-1 (PD-1) and vascular endothelial growth factor (VEGF) are associated with cancer development. The aim of the present study was to investigate the expression of CTLA-4, PD-1 and VEGF in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods: From January 2017 to January 2018, a total of 47 first-visit outpatients were recruited in the Sleep and Respiratory Disorder Center of Guangdong Provincial People's Hospital, and were divided into control group (N=17, mean age 54±12 years), mild-to-moderate OSAHS group (N=15, mean age 54±12 years) and severe OSAHS group (N=15, mean age 56±13 years). Venous blood was collected, plasma and cells were isolated, the expressions of PD-1 and CTLA-4 on the surface of CD(4)(+)T cells were detected by flow cytometry, and plasma VEGF was measured by enzyme linked immunosorbent assay. Results: The proportion of CD(4)(+)T cells in control group, mild-to-moderate OSAHS group and severe OSAHS group were respectively(38±8)%, (35±8)% and (38±6)% (F=1.228, P>0.05). The expression of CTLA-4 on CD(4)(+)T cells were respectively [1.13 (0.59~1.78)]%, [0.45 (0.16~1.43)]% and [0.87(0.47~1.46)]% (H=2.205, P>0.05). The expression of PD-1 on CD(4)(+)T cells were respectively [4.24 (2.12~6.03)]%, [3.54(2.69~5.09)]% and [3.31(1.67~8.25)]% (H=0.541, P>0.05). The concentrations of VEGF in control group, mild-to-moderate OSAHS group and severe OSAHS group were statistically different [(395.16±87.78) ng/L vs (452.85±107.97) ng/L vs (546.42±199.27) ng/L, F=4.827, P=0.013]. Compared with the control group, VEGF concentration was significantly increased in the severe OSAHS group(P<0.01). VEGF concentration was correlated negatively with the lowest SpO(2) (r (s)=-0.480,P=0.001), but positively with apnea-hypopnea index(r (s)=0.403, P=0.005), oxygen desaturation index (r (s)=0.378, P=0.010) and proportion of SpO(2) less than or equal to 90% of total sleep time(r (s)=0.547, P=0.000 3). Conclusion: There was no significant difference of PD-1 and CTLA-4 expression on CD(4)(+)T cells in patients with and without OSAHS. The expression of VEGF was elevated in OSAHS patients, and increased with the severity of OSAHS and hypoxia.