title: Flow cytometric analysis of peripheral blood dendritic cells in patients with severe sepsis.
abstract: BACKGROUND
  Dendritic cells (DC) play a key role in cell-mediated immunity. We aimed to analyse the number and function of peripheral blood (PB) myeloid and plasmacytoid DC (mDC/pDC) in patients with severe sepsis.
  
  
  METHODS
  Twenty-six septic patients, 20 surgical patients (abdominal aortic aneurysm) and 20 healthy controls were enrolled in this prospective study.
  
  
  RESULTS
  At day 1 (enrollment in the study), septic patients showed in comparison with healthy controls, decreased mDC (P < 0.001) and increased pDC (P = 0.03), resulting in a reduction of the mDC/pDC ratio (P < 0.001). Surgery induced a decrease in both mDCs and pDCs level, without modification of mDC/pDC ratio. Septic patients included 15 survivors and 11 nonsurvivors. At day 1 no significant difference was found in mDC between the two groups, while pDCs were significantly higher in nonsurvivors (P = 0.03). At the outcome, mDC were selectively increased with respect to day 1 in survivors (P = 0.001), while no significant differences were observed as far as pDC count is concerned in both groups. Sorted DC from septic patients showed in comparison with healthy controls, reduced levels of HLA DR (P < 0.001), CD11c (P < 0.001), CD83 (P = 0.006) and of costimulatory molecule CD86 (P = 0.003); an up-regulation of chemokine receptor CXCR4 (P = 0.031) and increased apoptosis (P < 0.001).
  
  
  CONCLUSIONS
  Sepsis has a profound effect on PB DC compartment. These alterations appear to be sepsis-specific. Increased apoptosis and alteration of migration and trafficking mechanism may be involved in DC compartment modification. DC alterations could contribute to sepsis-mediated immunoparalysis.
authors.affiliation: Servizio Anestesia e Rianimazione II, IRCCS Policlinico, S. Matteo and University of Pavia, Pavia, Italy. francesca_riccardi@libero.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Riccardi
authors.forename: Matteo G
authors.initials: MG
authors.lastname: Della Porta
authors.forename: Bianca
authors.initials: B
authors.lastname: Rovati
authors.forename: Alberto
authors.initials: A
authors.lastname: Casazza
authors.forename: Danila
authors.initials: D
authors.lastname: Radolovich
authors.forename: Mara
authors.initials: M
authors.lastname: De Amici
authors.forename: Marco
authors.initials: M
authors.lastname: Danova
authors.forename: Martin
authors.initials: M
authors.lastname: Langer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000737:chemistry / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018189:Immunomagnetic Separation; D008297:Male; D008875:Middle Aged; D022423:Myeloid Cells / Q000737:chemistry / Q000473:pathology*; D011446:Prospective Studies; D018805:Sepsis / Q000097:blood / Q000401:mortality / Q000473:pathology*; D055815:Young Adult