title: Quantitative measurement of monocyte HLA-DR expression in the identification of early-onset neonatal infection.
abstract: BACKGROUND
  This study aimed to evaluate the diagnostic utilities of monocyte HLA-DR as an infection marker in the identification of early-onset clinical infection and pneumonia in newborn infants.
  
  
  METHODS
  Term newborns in whom infection was suspected when they were <72 h of age were eligible for enrollment in the study. C-reactive protein (CRP), monocyte HLA-DR and neutrophil CD64 expressions were quantitatively measured at the time of sepsis evaluation (0 h) and 24 h afterwards by flow cytometry and standard laboratory method.
  
  
  RESULTS
  A total of 288 infants with suspected sepsis were investigated, and 93 were found to be clinically infected. There were no significant differences in monocyte HLA-DR expression between the infected, non-infected and control groups at 0 h (median (interquartile range): 13,986 (10,994-18,544), 14,234 (12,045-17,474) and 18,441 (14,250-21,537) antibody phycoerythrin (PE) molecules bound/cell), and between infected and non-infected infants at 24 h (median (interquartile range): 17,772 (12,933-25,167) and 19,406 (14,885-24,225) antibody PE molecules bound/cell). The areas under the receiver operating characteristics (ROC) curves for HLA-DR, CD64 and CRP were 0.52-0.54, 0.88-0.94 and 0.75-0.77, respectively. We were unable to determine an optimal cutoff value for HLA-DR, as the diagnostic utilities of any cutoff point on the ROC curves were unable to satisfy the criteria (i.e. sensitivity and specificity >or=80%) for consideration as an useful diagnostic marker of infection.
  
  
  CONCLUSIONS
  Our findings did not support the use of monocyte HLA-DR alone or in combination with other infection markers in the diagnosis of early-onset clinical infection and pneumonia in term newborns.
authors.affiliation: Department of Paediatrics, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China. pakcheungng@cuhk.edu.hk
authors.forename: Pak Cheung
authors.initials: PC
authors.lastname: Ng
authors.forename: Geng
authors.initials: G
authors.lastname: Li
authors.forename: Kit Man
authors.initials: KM
authors.lastname: Chui
authors.forename: Winnie Chiu Wing
authors.initials: WC
authors.lastname: Chu
authors.forename: Karen
authors.initials: K
authors.lastname: Li
authors.forename: Raymond Pui On
authors.initials: RP
authors.lastname: Wong
authors.forename: Tai Fai
authors.initials: TF
authors.lastname: Fok
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002097:C-Reactive Protein / Q000032:analysis; D004927:Escherichia coli Infections / Q000175:diagnosis; D006684:HLA-DR Antigens / Q000032:analysis*; D006801:Humans; D007231:Infant, Newborn; D007239:Infections / Q000175:diagnosis* / Q000276:immunology; D009000:Monocytes / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D010799:Phycoerythrin / Q000276:immunology; D018410:Pneumonia, Bacterial / Q000382:microbiology; D012372:ROC Curve; D017452:Receptors, IgG / Q000032:analysis; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000382:microbiology; D013290:Streptococcal Infections / Q000175:diagnosis
chemical_list: D015415:Biomarkers; D006684:HLA-DR Antigens; D017452:Receptors, IgG; D010799:Phycoerythrin; D002097:C-Reactive Protein