title: High regulatory T-cell levels at 1 year posttransplantation predict long-term graft survival among kidney transplant recipients.
abstract: BACKGROUND
  Regulatory T cells (Tregs) have gained an important role in mechanisms of tolerance and protection against the transplant rejection. However, only limited retrospective data have shown a relationship between peripheral blood Tregs and better long-term graft survival. The purpose of the present study was to investigate prospectively circulating Treg levels and their association with long-term graft survival.
  
  
  METHODS
  Ninety kidney transplant recipients underwent measurement of Treg levels in peripheral blood before as well as at 6 months and 1 year posttransplantation. Receiver operating characteristic curves were applied to test the sensitivity and specificity of Treg levels to predict prognosis.
  
  
  RESULTS
  Treg levels before transplantation correlated with those at 6 months and 12 months posttransplantation (P < .001 and P = .002, respectively). Patients who maintained high Treg levels (above 70th percentile) at both 6 and 12 months displayed better long-term graft survival at 4 and 5 years follow-up (P = .04 and P = .043 respectively). There was no effect on patient survival.
  
  
  CONCLUSIONS
  Detection of high levels of peripheral blood Tregs was associated with better graft survival possibly using as a potential marker of prognosis.
authors.affiliation: Immunology Service, Hospital Universitario Marqués de Valdecilla-IFIMAV, Santander, Spain.
authors.forename: D
authors.initials: D
authors.lastname: San Segundo
authors.forename: G
authors.initials: G
authors.lastname: Fernández-Fresnedo
authors.forename: E
authors.initials: E
authors.lastname: Rodrigo
authors.forename: J C
authors.initials: JC
authors.lastname: Ruiz
authors.forename: M
authors.initials: M
authors.lastname: González
authors.forename: C
authors.initials: C
authors.lastname: Gómez-Alamillo
authors.forename: M
authors.initials: M
authors.lastname: Arias
authors.forename: M
authors.initials: M
authors.lastname: López-Hoyos
mesh_terms: D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D006085:Graft Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D013997:Time Factors; D016896:Treatment Outcome; D015854:Up-Regulation