title: Association of telomere length of peripheral blood leukocytes with hematopoietic relapse, malignant transformation, and survival in severe aplastic anemia.
abstract: BACKGROUND
  Critically short telomeres produce apoptosis, cell senescence, and chromosomal instability in tissue culture and animal models. Variations in telomere length have been reported in severe aplastic anemia but their clinical significance is unknown.
  
  
  OBJECTIVE
  To investigate the relationship between telomere length and clinical outcomes in severe aplastic anemia.
  
  
  METHODS
  Single institution analysis of 183 patients with severe aplastic anemia who were treated in sequential prospective protocols at the National Institutes of Health from 2000 to 2008. The pretreatment leukocyte age-adjusted telomere length of patients with severe aplastic anemia consecutively enrolled in immunosuppression protocols with antithymocyte globulin plus cyclosporine for correlation with clinical outcomes were analyzed.
  
  
  METHODS
  Hematologic response, relapse, clonal evolution, and survival.
  
  
  RESULTS
  There was no relationship between hematologic response and telomere length with response rates of 56.5% of 46 patients in the first, 54.3% of 46 in the second, 60% of 45 in the third, and 56.5% of 46 in the fourth quartiles. Multivariate analysis demonstrated that telomere length was associated with relapse, clonal evolution, and mortality. Evaluated as a continuous variable, telomere length inversely correlated with the probability of hematologic relapse (hazard ratio [HR], 0.16; 95% confidence interval [CI], 0.03-0.69; P = .01). The probability of clonal evolution was higher in patients in the first quartile (24.5%; 95% CI, 8.7%-37.5%) than in quartiles 2 through 4 (8.4%; 95% CI, 3.2%-13.3%; P = .009), and evolution to monosomy 7 or complex cytogenetics was more common in the first quartile (18.8%; 95% CI, 3.5%-31.6%) [corrected] than in quartiles 2 through 4 (4.5%; 95% CI, 0.5%-8.2%; P = .002) [corrected]. Survival between these 2 groups differed, with 66% (95% CI, 52.9%-82.5%) surviving 6 years in the first quartile compared with 83.8% (95% CI, 77.3%-90.9%) in quartiles 2 through 4 (P = .008).
  
  
  CONCLUSIONS
  In a cohort of patients with severe aplastic anemia receiving immunosuppressive therapy, telomere length was unrelated to response but was associated with risk of relapse, clonal evolution, and overall survival.
authors.affiliation: Hematology Branch, National Heart, Lung, and Blood Institute, 10 Center Dr, Bldg 10 CRC, Room 3-5140, MSC 1202, Bethesda, MD 20892-1202, USA. scheinbp@mail.nih.gov
authors.forename: Phillip
authors.initials: P
authors.lastname: Scheinberg
authors.forename: James N
authors.initials: JN
authors.lastname: Cooper
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Sloand
authors.forename: Colin O
authors.initials: CO
authors.lastname: Wu
authors.forename: Rodrigo T
authors.initials: RT
authors.lastname: Calado
authors.forename: Neal S
authors.initials: NS
authors.lastname: Young
mesh_terms: D000328:Adult; D000741:Anemia, Aplastic / Q000097:blood / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D043171:Chromosomal Instability; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007962:Leukocytes / Q000648:ultrastructure; D008297:Male; D011379:Prognosis; D012008:Recurrence; D016019:Survival Analysis; D016615:Telomere / Q000648:ultrastructure*; D016896:Treatment Outcome
chemical_list: D007166:Immunosuppressive Agents