Platelet-associated Inflammation in Severe Sepsis
Platelet-associated Inflammation in Severe Sepsis
Sepsis represents a serious public health issue characterized by a complex inflammatory
 response. In addition to their hemostatic role, platelets display inflammatory functions by
 secreting a variety of immunomodulatory factors and interacting with circulating immune
 cells. The investigators postulate that, in severe sepsis, platelets become activated and
 release amounts of different soluble inflammatory molecules that contribute to
 sepsis-associated inflammation. First, the investigators propose to assess whether severe
 sepsis impairs the ability of platelets to release soluble CD40L (sCD40L), an powerful
 platelet-derived immunomodulatory molecule, in ICU patients with S. aureus documented
 infection, ICU patients with documented infection involving other bacterial species, compared
 to ICU patients with inflammation of noninfectious origin and healthy blood donors. Then, the
 investigators wish to assess whether the bacterial species affects the release of platelet
 sCD40L and by an extensive screening of platelet soluble factors, the investigators propose
 to set up profiles of inflammatory molecules associated with the type of infection. Finally,
 the investigators will analyze platelets' activation state and their association with
 circulating immune, according to the type of infection. Therefore, this project is expected
 to assess to which extent the platelet inflammatory function is super-activated in severe
 sepsis and to identify new platelet-related biomarkers of sepsis.
Inclusion criteria

 Common inclusion criteria for ICU patients : Signed informed consent, Patient affiliated or
 entitled to a social security, aged over 18 years,

 -  Criteria for blood donor voluntary : to weigh more than 50 kg

 -  Criteria for severe sepsis group : Sepsis with failure of at least one organ, severe
 sepsis for less than 72 hours, sepsis with bacteria S. aureus, S. pneumoniae or E.
 coli.

 -  Criteria for uninfectious inflammatory syndrome group : patients operate since less
 than 24 hours of hip or knee surgery, Absence of systemic infection

 Exclusion Criteria

 -  failure to participate at the study

 -  Patients with a aspirin treatment has continued throughout severe sepsis

 -  Patients with an appropriate antibiotic therapy for more than 72 hours

 -  Patients with a platelet transfusion in the week before inclusion or 72 hours after a
 surgical gesture or the occurrence of sepsis

 -  Patients with the platelet account is less than 30 000 per cubic millimeter the day of
 the sampling

 -  Patients with a severe sepsis who had a surgical gesture previous week the inclusion

 -  All clinical sequelae or biological at the selection

 -  pregnant woman

 -  Patients with a treatment by platelet aggregation has continued throughout severe
 sepsis