title: Specific MAIT cell behaviour among innate-like T lymphocytes in critically ill patients with severe infections.
abstract: OBJECTIVE
  In between innate and adaptive immunity, the recently identified innate-like mucosal-associated invariant T (MAIT) lymphocytes display specific reactivity to non-streptococcal bacteria. Whether they are involved in bacterial sepsis has not been investigated. We aimed to assess the number and the time course of circulating innate-like T lymphocytes (MAIT, NKT and γδ T cells) in critically ill septic and non-septic patients and to establish correlations with the further development of intensive care unit (ICU)-acquired infections.
  
  
  METHODS
  We prospectively enrolled consecutive patients with severe sepsis and septic shock. Controls were critically ill patients with non-septic shock and age-matched healthy subjects. Circulating innate-like lymphocytes were enumerated using a flow cytometry assay at day 1, 4 and 7.
  
  
  RESULTS
  One hundred and fifty six patients (113 severe bacterial infections, 36 non-infected patients and 7 patients with severe viral infections) and 26 healthy subjects were enrolled into the study. Patients with severe bacterial infections displayed an early decrease in MAIT cell count [median 1.3/mm(3); interquartile range (0.4-3.2)] as compared to control healthy subjects [31.1/mm(3) (12.1-45.2)], but also to non-infected critically ill patients [4.3/mm(3) (1.4-13.2)] (P < 0.0001 for all comparisons). In contrast NKT and γδ T cell counts did not differ between patients groups. The multivariate analysis identified non-streptococcal bacterial infection as an independent determinant of decrease in MAIT cell count. Furthermore, the incidence of ICU-acquired infections was higher in patients with persistent MAIT cell depletion.
  
  
  CONCLUSIONS
  This large human study provides valuable information about MAIT cells in severe bacterial infections. The persistent depletion of MAIT cells is associated with the further development of ICU-acquired infections.
authors: Réanimation médicale, Hôpital Cochin AP-HP, 27 rue du Faubourg Saint Jacques, 75014, Paris, France. dgrimaldi@ch-versailles.fr.|Institut Cochin INSERM U1016, Paris, France. dgrimaldi@ch-versailles.fr.|CNRS UMR8104, Paris, France. dgrimaldi@ch-versailles.fr.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France. dgrimaldi@ch-versailles.fr.|Réanimation médico-chirurgicale, Centre Hospitalier de Versailles, Le Chesnay, France. dgrimaldi@ch-versailles.fr.
authors: David
authors: D
authors: Grimaldi
authors: Institut Curie, Biologie des Tumeurs, Paris, France.|INSERM U932, Paris, France.|Centre d'investigation clinique CICBT507, Institut Curie/Institut Gustave Roussy, Paris, France.
authors: Lionel
authors: L
authors: Le Bourhis
authors: Réanimation médicale, Hôpital Cochin AP-HP, 27 rue du Faubourg Saint Jacques, 75014, Paris, France.
authors: Bertrand
authors: B
authors: Sauneuf
authors: Université Paris Descartes, Sorbonne Paris Cité, Paris, France.|Centre d'épidémiologie clinique, Hôpital Hotel-Dieu, AP-HP, Paris, France.
authors: Agnès
authors: A
authors: Dechartres
authors: Institut Cochin INSERM U1016, Paris, France.|CNRS UMR8104, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors: Christophe
authors: C
authors: Rousseau
authors: Institut Cochin INSERM U1016, Paris, France.|CNRS UMR8104, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors: Fatah
authors: F
authors: Ouaaz
authors: Institut Curie, Biologie des Tumeurs, Paris, France.|INSERM U932, Paris, France.|Centre d'investigation clinique CICBT507, Institut Curie/Institut Gustave Roussy, Paris, France.
authors: Maud
authors: M
authors: Milder
authors: Institut Curie, Biologie des Tumeurs, Paris, France.|INSERM U932, Paris, France.|Centre d'investigation clinique CICBT507, Institut Curie/Institut Gustave Roussy, Paris, France.
authors: Delphine
authors: D
authors: Louis
authors: Réanimation médicale, Hôpital Cochin AP-HP, 27 rue du Faubourg Saint Jacques, 75014, Paris, France.|Institut Cochin INSERM U1016, Paris, France.|CNRS UMR8104, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors: Jean-Daniel
authors: JD
authors: Chiche
authors: Réanimation médicale, Hôpital Cochin AP-HP, 27 rue du Faubourg Saint Jacques, 75014, Paris, France.|Institut Cochin INSERM U1016, Paris, France.|CNRS UMR8104, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors: Jean-Paul
authors: JP
authors: Mira
authors: Institut Curie, Biologie des Tumeurs, Paris, France.|INSERM U932, Paris, France.|Centre d'investigation clinique CICBT507, Institut Curie/Institut Gustave Roussy, Paris, France.
authors: Olivier
authors: O
authors: Lantz
authors: Réanimation médicale, Hôpital Cochin AP-HP, 27 rue du Faubourg Saint Jacques, 75014, Paris, France. frederic.pene@cch.aphp.fr.|Institut Cochin INSERM U1016, Paris, France. frederic.pene@cch.aphp.fr.|CNRS UMR8104, Paris, France. frederic.pene@cch.aphp.fr.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France. frederic.pene@cch.aphp.fr.
authors: Frédéric
authors: F
authors: Pène
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001424:Bacterial Infections / Q000276:immunology*; D016638:Critical Illness; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007694:Killer Cells, Natural / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000276:immunology; D011446:Prospective Studies; D012720:Severity of Illness Index; D013601:T-Lymphocytes / Q000276:immunology*