title: Telomerase activity increased and telomere length shortened in peripheral blood cells from patients with immune thrombocytopenia.
abstract: OBJECTIVE
  To evaluate the telomere/telomerase system and its clinical significance in immune thrombocytopenia (ITP) patients.
  
  
  METHODS
  A total of 237 ITP patients, 20 SLE patients and 200 age-and sex-matched healthy controls were included in this study. CD4(+), CD8(+) and CD19(+) lymphocytes were purified by magnetic beads sorting from peripheral blood of 37 active chronic ITP patients and 22 age-and sex-matched healthy controls. Telomerase activity was assayed by Telo TTAGGG Telomerase PCR ELISA KIT. The relative telomere length of peripheral blood mononuclear cell (PBMC) was measured by a quantitative polymerase chain reaction-based method (Q-PCR) from 200 ITP patients and 178 age-and sex-matched healthy controls.
  
  
  RESULTS
  Telomerase activity was increased in CD4(+), CD8(+) and CD19(+) lymphocytes from ITP patients compared to those from healthy controls (p = 0.000). The level of telomerase activity in CD19(+) lymphocyte was higher than those in CD4(+) and CD8(+) lymphocytes. Telomerase activity of CD19+ lymphocytes had a modest negative correlation with platelet count in ITP patients (p = 0.042). The relative telomere length of PBMC in ITP patients was significantly shorter than that in the healthy controls (p = 0.002). Telomere length of PBMC in active ITP patients was significantly shorter than that in the controls (p = 0.000) and a tendency to be shorter even in inactive ITP patients (p = 0.065). Moreover, the telomere length in refractory and non-refractory ITP patients were both significantly shorter than that in the controls (p = 0.025; p = 0.000). However no significant difference in telomere length of PBMC was found between refractory ITP patients and non-refractory ITP patients (p = 0.234).
  
  
  CONCLUSIONS
  An abnormal regulating telomere/telomerase system might be involved in the pathogenesis of ITP. Further studies may elucidate whether the telomere length could be considered as a predictive biomarker for the prognosis of ITP.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 288 Nanjing Road, Tianjin, 300020, People's Republic of China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Qi
authors.forename: Hu
authors.initials: H
authors.lastname: Zhou
authors.forename: Zeping
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Yang
authors.forename: Donglei
authors.initials: D
authors.lastname: Zhang
authors.forename: Huyuan
authors.initials: H
authors.lastname: Li
authors.forename: Ruimin
authors.initials: R
authors.lastname: Ren
authors.forename: Renchi
authors.initials: R
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D018941:Antigens, CD19 / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens / Q000378:metabolism; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism*; D012307:Risk Factors; D019098:Telomerase / Q000378:metabolism*; D059506:Telomere Shortening; D055815:Young Adult
chemical_list: D018941:Antigens, CD19; D015704:CD4 Antigens; D016827:CD8 Antigens; D019098:Telomerase