title: Monocyte HLA-DR expression and neutrophil CD64 expression as biomarkers of infection in critically ill neonates and infants.
abstract: BACKGROUND
  Reduced monocyte HLA-DR expression and increased neutrophil CD64 expression have been proposed as biomarkers of infection.
  
  
  METHODS
  From 2009-2011, blood samples from neonatal intensive care unit (NICU) and pediatric intensive care unit (ICU) patients <1 y of age were collected at enrollment and during subsequent evaluation for suspected infection, if it occurred. Samples were analyzed for monocyte HLA-DR and neutrophil CD64 expression levels by flow cytometry.
  
  
  RESULTS
  Forty-seven infants had study samples collected at enrollment; 26 infants had study samples collected at the time of a suspected infection. At enrollment, there was an inverse relationship between neutrophil CD64 expression and age (P ≤ 0.047). At the time of suspected infection, infants with an infection demonstrated a lower percentage of HLA-DR+ monocytes (P = 0.02, area under the curve (AUC) 0.78), higher percentage of CD64+ neutrophils (P = 0.009, AUC 0.81), and higher neutrophil CD64 expression levels (P = 0.04, AUC 0.75).
  
  
  CONCLUSIONS
  Monocyte HLA-DR and neutrophil CD64 expression in critically ill infants are related to age and infection.
authors: Mayo Graduate School, Mayo Clinic, Rochester, Minnesota.
authors: Justin E
authors: JE
authors: Juskewitch
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors: Roshini S
authors: RS
authors: Abraham
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors: Stacy C
authors: SC
authors: League
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Sarah M
authors: SM
authors: Jenkins
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Carin Y
authors: CY
authors: Smith
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Felicity T
authors: FT
authors: Enders
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors: Stefan K
authors: SK
authors: Grebe
authors: Division of Neonatal Medicine, Mayo Clinic, Rochester, Minnesota.
authors: William A
authors: WA
authors: Carey
authors: Division of Pediatric Infectious Diseases, Mayo Clinic, Rochester, Minnesota.
authors: W Charles
authors: WC
authors: Huskins
mesh_terms: D000367:Age Factors; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D016638:Critical Illness; D003430:Cross-Sectional Studies; D005260:Female; D005434:Flow Cytometry; D005865:Gestational Age; D006684:HLA-DR Antigens / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007363:Intensive Care Units, Neonatal; D015278:Intensive Care Units, Pediatric; D007958:Leukocyte Count; D008297:Male; D009000:Monocytes / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D012372:ROC Curve; D017452:Receptors, IgG / Q000097:blood*; D018805:Sepsis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology
chemical_list: D015415:Biomarkers; D006684:HLA-DR Antigens; D011498:Protein Precursors; D017452:Receptors, IgG; D002116:Calcitonin; D002097:C-Reactive Protein