Decreased Programmed Death-1 Expression on the T Cells of Patients With Ankylosing Spondylitis

摘要

Background: Programmed death-1 (PD-1) plays a vital role in down-modulating immune responses and maintaining peripheral tolerance. Methods: The authors have investigated the inducible expression of PD-1 on activated T cells from patients with ankylosing spondylitis (AS). Thirty patients with AS and 31 unrelated healthy controls (HCs) were recruited in this study. The expression of PD-1 on T cells harvested from nonstimulated (t(0)) or stimulated cultures with phytohemagglutinin for 24 hours (t(24)) was determined by flow cytometry. The multiple levels of the PD-1 expression on stimulated and nonstimulated cells from each individual's sample (t(24)/t(0)) represented as the degree of the inducible effect on PD-1 expression. Results: The expression of PD-1 on nonstimulated T cells presented no significant difference between AS group and HC group (P > 0.05). After stimulation, the degree of effect on PD-1 expression of CD4(+), CD4(+) CD25(+), CD4(+)CD25(high), CD4(+)CD25(low) and CD4(+)CD25(-) T cells were significantly lower in patients with AS than those in HC group (1.9 +/- 0.9 versus 3.6 +/- 2.3, 9.7 +/- 7.4 versus 17.8 +/- 12.6, 87.8 +/- 48.6 versus 157.3 +/- 117.0, 3.7 +/- 1.4 versus 7.3 +/- 2.4, 0.5 +/- 0.3 versus 1.1 +/- 0.6, respectively, P < 0.05). However, there was no significant difference of the effect on all lymphocytes and CD8(+) T cells between patients with AS and HCs (P. 0.05). Conclusions: The decreased inducible expression of PD-1 on active T lymphocytes, especially on CD4(+)CD25(high) and CD4(+)CD25(+) T cells, may be one of important factors involved in the development of AS.