title: Decreased programmed death-1 expression on the T cells of patients with ankylosing spondylitis.
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.
authors.affiliation: Department of Clinical Laboratory (LZ, HX, LH, YX, HL, ZZ, WH, XL), The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China; Department of Clinical Laboratory (YZ), Yantai Yuhuangding Hospital, Yantai, China; and Departments of Orthpaedics Trauma (CZ) and Rheumatology (LS), The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Lianlian
authors.initials: L
authors.lastname: Zhou
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huiying
authors.initials: H
authors.lastname: Xu
authors.forename: Liping
authors.initials: L
authors.lastname: Hu
authors.forename: Chunwu
authors.initials: C
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Yaosheng
authors.initials: Y
authors.lastname: Xie
authors.forename: Hong
authors.initials: H
authors.lastname: Lu
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wangqiang
authors.initials: W
authors.lastname: Hu
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D008297:Male; D008875:Middle Aged; D061026:Programmed Cell Death 1 Receptor / Q000276:immunology*; D013167:Spondylitis, Ankylosing / Q000276:immunology* / Q000473:pathology
chemical_list: C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor