title: T-Cell Phenotypes Predictive of Frailty and Mortality in Elderly Nursing Home Residents.
abstract: To determine whether immune phenotypes associated with immunosenescence are predictive of frailty and mortality within 1-year in elderly nursing home residents.
  
  
  
  Cross sectional study of frailty; prospective cohort study of mortality.
  
  
  
  Thirty-two nursing homes in four Canadian cities between September 2009 and October 2011.
  
  
  
  Nursing home residents aged 65 and older (N = 1,072, median age 86, 72% female).
  
  
  
  After enrollment, peripheral blood mononuclear cells were obtained and analyzed using flow cytometry for CD4+and CD8+T-cell subsets (naïve, memory (central, effector, terminally differentiated, senescent), and regulatory T-cells) and cytomegalovirus (CMV)-reactive CD4+and CD8+T-cells. Multilevel linear regression analysis was performed to determine the relationship between immune phenotypes and frailty; frailty was measured at the time of enrollment using the Frailty Index. A Cox proportional hazards model was used to determine the relationship between immune phenotypes and time to death (within 1 year).
  
  
  
  Mean Frailty Index was 0.44 ± 0.13. Multilevel regression analysis showed that higher percentages of naïve CD4+T-cells (P = .001) and effector memory CD8+T-cells (P = .02) were associated with a lower mean Frailty Index, whereas a higher percentage of CD8+central memory T-cells was associated with a higher mean Frailty Index score (P = .02). One hundred fifty one (14%) members of the cohort died within 1 year. Multivariable analysis showed a significant negative multiplicative interaction between age and percentage of CMV-reactive CD4+T-cells (hazard ratio = 0.87, 95% confidence interval = 0.79-0.96). No other significant factors were identified.
  
  
  
  Immune phenotypes found to be predictive of frailty and mortality in this study can help further understanding of immunosenescence and may provide a rationale for future intervention studies designed to modulate immunity.
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.|Public Health Ontario, Toronto, Ontario, Canada.
authors: Jennie
authors: J
authors: Johnstone
authors: McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada.
authors: Robin
authors: R
authors: Parsons
authors: McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada.
authors: Fernando
authors: F
authors: Botelho
authors: McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada.
authors: Jamie
authors: J
authors: Millar
authors: Canadian Center for Vaccinology, IWK Health Center and Capital Health, Dalhousie University, Halifax, Nova Scotia, Canada.
authors: Shelly
authors: S
authors: McNeil
authors: Department of Medicine, Geriatrics Division, Research Center on Aging, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors: Tamas
authors: T
authors: Fulop
authors: Health Sciences North Research Institute, Sudbury, Ontario, Canada.
authors: Janet E
authors: JE
authors: McElhaney
authors: Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors: Melissa K
authors: MK
authors: Andrew
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
authors: Stephen D
authors: SD
authors: Walter
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.|Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors: P J
authors: PJ
authors: Devereaux
authors: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.
authors: Mehrnoush
authors: M
authors: Malek
authors: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.|Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Ryan R
authors: RR
authors: Brinkman
authors: McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada.|Department Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.|Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
authors: Jonathan
authors: J
authors: Bramson
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.|Department of Medicine, McMaster University, Hamilton, Ontario, Canada.|Department Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.|Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
authors: Mark
authors: M
authors: Loeb
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003587:Cytomegalovirus / Q000276:immunology; D005260:Female; D016330:Frail Elderly; D006801:Humans; D000068884:Immunosenescence; D008297:Male; D009026:Mortality; D015999:Multivariate Analysis; D009735:Nursing Homes
chemical_list: D015415:Biomarkers
keywords: frailty; immune biomarker; immunosenescence; mortality; nursing home