title: S100A8/A9 mRNA induction in an ex vivo model of endotoxin tolerance: roles of IL-10 and IFNγ.
abstract: OBJECTIVE
  Septic syndromes are the leading cause of death in intensive care units. They are characterized by the development of immune dysfunctions such as endotoxin tolerance (ET), whose intensity and duration are associated with increased risk of nosocomial infections and mortality. Alarmins S100A8 and S100A9 have been shown to be increased after septic shock. Importantly, a delayed S100A9 mRNA increase predicts hospital-acquired infection in patients. The aim of this study was to investigate the regulation of S100A8 and S100A9 mRNA expression in an ex vivo model of ET.
  
  
  METHODS
  ET was reproduced ex vivo by priming healthy peripheral blood mononuclear cells (number of donors  = 9 to 10) with low-dose endotoxin (2 ng/ml) before stimulation with high dose endotoxin (100 ng/ml). S100A8 and S100A9 mRNA levels were measured by quantitative real-time polymerase chain reactions.
  
  
  RESULTS
  ET was established by observing decreased TNFα and increased IL-10 transcriptomic responses to two subsequent endotoxin challenges. Interestingly, ET was associated with increased S100A8 and S100A9 mRNA expression ex vivo. We showed that IL-10 played a role in this process, since S100A8 and S100A9 mRNA increases were significantly abrogated by IL-10 blockade in the model. Conversely, treatment with rIFN-γ, a pro-inflammatory and immunostimulating molecule known to block ET induction, was able to restore normal S100A8 and S100A9 mRNA in this model.
  
  
  CONCLUSIONS
  In this ex vivo model, we observed that S100A8 and S100A9 mRNA expression was significantly increased during ET. This reproduced ex vivo the observations we had previously made in septic shock patients. Interestingly, IL-10 blockade and rIFN-γ treatment partially abrogated S100A8/A9 mRNA increases in this model. Pending confirmation in larger, independent clinical studies, these preliminary results suggest that S100A8 and S100A9 mRNA levels might be used as surrogate markers of ET and as stratification tools for personalized immunotherapy in septic shock patients.
authors: Hospices Civils de Lyon - Intensive Care Unit, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France; Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France; EAM 4174 "Hemostasis, inflammation and sepsis" Hospices Civils de Lyon - Université Claude Bernard Lyon I, Lyon, France.
authors: Mathieu
authors: M
authors: Fontaine
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France.
authors: Séverine
authors: S
authors: Planel
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France.
authors: Estelle
authors: E
authors: Peronnet
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France.
authors: Fanny
authors: F
authors: Turrel-Davin
authors: Hospices Civils de Lyon - Intensive Care Unit, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France; EAM 4174 "Hemostasis, inflammation and sepsis" Hospices Civils de Lyon - Université Claude Bernard Lyon I, Lyon, France.
authors: Vincent
authors: V
authors: Piriou
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France.
authors: Alexandre
authors: A
authors: Pachot
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France; EAM 4174 "Hemostasis, inflammation and sepsis" Hospices Civils de Lyon - Université Claude Bernard Lyon I, Lyon, France; Hospices Civils de Lyon - Immunology Laboratory, Hôpital Edouard Herriot, Lyon, France.
authors: Guillaume
authors: G
authors: Monneret
authors: Hospices Civils de Lyon - Intensive Care Unit, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France; Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France; EAM 4174 "Hemostasis, inflammation and sepsis" Hospices Civils de Lyon - Université Claude Bernard Lyon I, Lyon, France.
authors: Alain
authors: A
authors: Lepape
authors: Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France; EAM 4174 "Hemostasis, inflammation and sepsis" Hospices Civils de Lyon - Université Claude Bernard Lyon I, Lyon, France; Hospices Civils de Lyon - Immunology Laboratory, Hôpital Edouard Herriot, Lyon, France.
authors: Fabienne
authors: F
authors: Venet
mesh_terms: D000328:Adult; D040501:Calgranulin A / Q000235:genetics* / Q000378:metabolism; D040502:Calgranulin B / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects*; D007371:Interferon-gamma / Q000378:metabolism*; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D040501:Calgranulin A; D040502:Calgranulin B; D008070:Lipopolysaccharides; D012333:RNA, Messenger; C106644:SOCS3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma