title: Markers of endothelial cell activation and immune activation are increased in patients with severe leptospirosis and associated with disease severity.
abstract: OBJECTIVE
  Previous studies concluded that haemorrhage is one of the most accurate prognostic factors of mortality in leptospirosis. Therefore, endothelial cell activation was investigated in relation to disease severity in severe leptospirosis.
  
  
  METHODS
  Prospective cohort study of severe leptospirosis patients. Plasma levels of sE-selectin and Von Willebrand factor (VWF) were determined. Consequently, an in vitro endothelial cell model was used to assess endothelial activation after exposure to virulent Leptospira. Finally, immune activation, as a potential contributing factor to endothelial cell activation, was determined by soluble IL2-receptor (sIL-2r) and soluble Fas-ligand (sFasL) levels.
  
  
  RESULTS
  Plasma levels of sE-selectin and VWF strongly increased in patients compared to healthy controls. Furthermore, sE-selectin was significantly elevated (203 ng/ml vs. 157 ng/ml, p < 0.05) in survivors compared to non-survivors. Endothelial cells exposed to virulent Leptospira showed increased VWF expression. E-selectin and ICAM-1 expression did not change. Immunohistochemistry revealed the presence of intracellular Leptospira and qPCR suggested replication. In vivo analysis showed that increased levels of sFasL and sIL-2r were both strongly associated with mortality. Furthermore sIL-2r levels were increased in patients that developed bleeding and significantly correlated to duration of hospital stay.
  
  
  CONCLUSIONS
  Markers of endothelial activation and immune activation were associated with disease severity in leptospirosis patients.
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands. Electronic address: m.goeijenbier@erasmusmc.nl.
authors.forename: Marco
authors.initials: M
authors.lastname: Goeijenbier
authors.affiliation: Department of Medicine, Dr. Kariadi Hospital, Faculty of Medicine, Diponegoro University, Semarang, Indonesia; National Reference Laboratory for Leptospirosis, Dr. Kariadi Hospital, Semarang, Indonesia.
authors.forename: M Hussein
authors.initials: MH
authors.lastname: Gasem
authors.affiliation: Department of Experimental Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Plasma Proteins, Sanquin Research, Amsterdam, The Netherlands.
authors.forename: Joost C M
authors.initials: JC
authors.lastname: Meijers
authors.affiliation: WHO/FAO/OIE and National Leptospirosis Reference Centre, KIT Biomedical Research, Amsterdam, The Netherlands.
authors.forename: Rudy A
authors.initials: RA
authors.lastname: Hartskeerl
authors.affiliation: WHO/FAO/OIE and National Leptospirosis Reference Centre, KIT Biomedical Research, Amsterdam, The Netherlands.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: WHO/FAO/OIE and National Leptospirosis Reference Centre, KIT Biomedical Research, Amsterdam, The Netherlands.
authors.forename: Marga G A
authors.initials: MG
authors.lastname: Goris
authors.affiliation: National Reference Laboratory for Leptospirosis, Dr. Kariadi Hospital, Semarang, Indonesia.
authors.forename: Bambang
authors.initials: B
authors.lastname: Isbandrio
authors.affiliation: Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Simone S
authors.initials: SS
authors.lastname: Schuller
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands; ARTEMIS One Health Research Institute, Utrecht, The Netherlands.
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands; ARTEMIS One Health Research Institute, Utrecht, The Netherlands.
authors.forename: Byron E E
authors.initials: BE
authors.lastname: Martina
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Eric C M
authors.initials: EC
authors.lastname: van Gorp
authors.affiliation: Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States.
authors.forename: Jarlath E
authors.initials: JE
authors.lastname: Nally
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands; WHO/FAO/OIE and National Leptospirosis Reference Centre, KIT Biomedical Research, Amsterdam, The Netherlands.
authors.forename: Jiri F P
authors.initials: JF
authors.lastname: Wagenaar
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D015331:Cohort Studies; D019040:E-Selectin / Q000097:blood; D042783:Endothelial Cells / Q000276:immunology* / Q000382:microbiology / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D053222:Fas Ligand Protein / Q000097:blood; D005260:Female; D061307:Human Umbilical Vein Endothelial Cells / Q000276:immunology / Q000382:microbiology; D006801:Humans; D007919:Leptospira / Q000276:immunology / Q000472:pathogenicity; D007922:Leptospirosis / Q000276:immunology* / Q000382:microbiology / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015375:Receptors, Interleukin-2 / Q000097:blood; D012720:Severity of Illness Index; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019040:E-Selectin; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D015375:Receptors, Interleukin-2; D014841:von Willebrand Factor
keywords: E-selectin; Endothelial cell; Leptospirosis; Von Willebrand factor; sFas ligand; sIL-2 receptor