title: Increased percentage of CD4+CD25+ regulatory T cells during septic shock is due to the decrease of CD4+CD25- lymphocytes.
abstract: OBJECTIVE
  The elevation of the percentage of regulatory CD4+CD25+ T lymphocytes (Treg) has been recently described during septic shock. The objective of the present study was to investigate whether this increased percentage was due to Treg proliferation.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Adult intensive care units in a university hospital.
  
  
  METHODS
  Patients with septic shock (n = 54) and healthy individuals (n = 30).
  
  
  METHODS
  None.
  
  
  RESULTS
  In patients, we first confirmed the increased percentage of Treg among CD4+ lymphocytes in comparison with healthy individuals. Surprisingly, regarding absolute counting, we demonstrated that both T CD4+ lineages (CD25+ and CD25-) were diminished immediately after the onset of shock. Then, whereas Treg returned rapidly to healthy donors values, CD4+CD25- T lymphocytes remained dramatically reduced. Finally, Foxp3 (Treg-related gene) messenger RNA quantification enabled us to definitively rule out a lack of proliferation since it was not increased during shock.
  
  
  CONCLUSIONS
  The increased percentage of Treg after shock is due not to their proliferation but to a decrease in CD4+CD25- T lymphocyte number. We hypothesize that it might be due to a resistance of Treg to apoptosis processes occurring during septic shock.
authors.affiliation: Immunology Laboratory, Lyon-Sud University Hospital, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Venet
authors.forename: Alexandre
authors.initials: A
authors.lastname: Pachot
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Debard
authors.forename: Julien
authors.initials: J
authors.lastname: Bohé
authors.forename: Jacques
authors.initials: J
authors.lastname: Bienvenu
authors.forename: Alain
authors.initials: A
authors.lastname: Lepape
authors.forename: Guillaume
authors.initials: G
authors.lastname: Monneret
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000276:immunology; D017209:Apoptosis; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D002454:Cell Differentiation; D019070:Cell Lineage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors; D006801:Humans; D007108:Immune Tolerance / Q000235:genetics / Q000276:immunology; D016130:Immunophenotyping; D037181:Lectins, C-Type; D017493:Leukocyte Common Antigens / Q000032:analysis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000032:analysis / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012772:Shock, Septic / Q000276:immunology*; D018709:Statistics, Nonparametric; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D013997:Time Factors; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D037181:Lectins, C-Type; D017493:Leukocyte Common Antigens; D015375:Receptors, Interleukin-2; D000099192:CD69 Antigens; C418974:FOXP3 protein, human