Decreased Programmed Death-1 Expression on the T Cells of Patients With Ankylosing Spondylitis. (June 2015) - Zhou, Lianlian
Abstract: 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 (t0 ) or stimulated cultures with phytohemagglutinin for 24 hours (t24 ) was determined by flow cytometry. The multiple levels of the PD-1 expression on stimulated and nonstimulated cells from each individual's sample (t24 /t0 ) 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.