title: Reduction of immunocompetent T cells followed by prolonged lymphopenia in severe sepsis in the elderly.
abstract: OBJECTIVE
  To investigate the immunological changes caused by severe sepsis in elderly patients.
  
  
  METHODS
  One-year, prospective observational study.
  
  
  METHODS
  Emergency department and intensive care unit of a single university hospital.
  
  
  METHODS
  Seventy-three patients with severe sepsis and 72 healthy donors.
  
  
  RESULTS
  In elderly septic patients (aged 65 yr and over), 3-month survival was significantly reduced compared with that for adult patients (18-64 yr) (60% vs. 89%, p < 0.01). We found that lymphopenia was prolonged for at least 21 days in elderly nonsurvivors of sepsis, while the number of lymphocytes recovered in both adult and elderly survivors of sepsis. In order to examine the immunological status of septic patients, blood samples were collected within 48 hrs of diagnosis of severe sepsis, and peripheral blood mononuclear cells were purified for flow cytometric analysis. T cell levels were significantly reduced in both adult and elderly septic patients, compared with those in healthy donors (56% and 57% reduction, respectively). Interestingly, the immunocompetent CD28+ subset of CD4+ T cells decreased, whereas the immunosuppressive PD-1+ T cells and the percentage of regulatory T cells (CD4+ T cells that are both Foxp3+ and CD25+) increased in elderly patients, especially nonsurvivors, presumably reflecting the initial signs of immunosuppression.
  
  
  CONCLUSIONS
  Reduction of immunocompetent T cells followed by prolonged lymphopenia may be associated with poor prognosis in elderly septic patients.
authors: Institute of Innovative Science and Technology, Tokai University School of Medicine, Isehara, Kanagawa, Japan. sg-inoue@is.icc.u-tokai.ac.jp
authors: Shigeaki
authors: S
authors: Inoue
authors: Kyoko
authors: K
authors: Suzuki-Utsunomiya
authors: Yoshinori
authors: Y
authors: Okada
authors: Takayuki
authors: T
authors: Taira
authors: Yumi
authors: Y
authors: Iida
authors: Naoya
authors: N
authors: Miura
authors: Tomoatsu
authors: T
authors: Tsuji
authors: Takeshi
authors: T
authors: Yamagiwa
authors: Seiji
authors: S
authors: Morita
authors: Tomoki
authors: T
authors: Chiba
authors: Takehito
authors: T
authors: Sato
authors: Sadaki
authors: S
authors: Inokuchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002561:Cerebrovascular Disorders / Q000276:immunology; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D007121:Immunocompetence; D007362:Intensive Care Units; D007564:Japan; D008231:Lymphopenia / Q000150:complications / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D036301:Qualitative Research; D018805:Sepsis / Q000150:complications / Q000276:immunology*; D016019:Survival Analysis