title: Diminished HLA-DR expression on monocyte and dendritic cell subsets indicating impairment of cellular immunity in pre-term neonates: a prospective observational analysis.
abstract: OBJECTIVE
  The risk of neonates for severe infection/sepsis is reciprocally proportional to gestational age and birth weight. As monocytes and dendritic cells (DC) are recognised key antigen-presenting immune cells, we aimed to elucidate whether neonatal age is associated with reduced expression of human-leukocyte antigen-DR (HLA-DR) antigens on subsets of monocytes and DCs.
  
  
  METHODS
  Forty-three consecutive neonates (20 male, mean gestational age 236.0±26.8 days; mean 1-min Apgar score 7.5±2.0) were included in a monocentric prospective observational analysis. Patients were grouped according to gestational age (n=15 full-term, n=28 pre-term defined as <33 weeks). Ten healthy adult volunteers were assessed also. Flow-cytometric assessment of HLA-DR expression was performed in subsets of peripheral blood myeloid and plasmacytoid DCs (MDC and PDC) and monocytes (CD14brightCD16negative/CD14positiveCD16positive/CD14dimCD16positive). Clinical and routine laboratory data were followed up.
  
  
  RESULTS
  At birth, leukocyte counts were increased in full-term neonates. Monocyte counts were significantly increased in neonates when compared with adults (all P<0.05). A significant numerical increase of CD14brightCD16negative and CD14positiveCD16positive monocytes was noted in pre-term and full-term neonates (all P<0.05), while HLA-DR expression in these subsets was significantly diminished (most pronounced in pre-term infants, P<0.0001). MDC and PDC HLA-DR expression was reduced also (all P<0.05). Clinical indices (e.g., pH, days on antibiotics/mechanical ventilation, fever/sepsis) were not found to correlate with immunological indices.
  
  
  CONCLUSIONS
  We observed a markedly diminished HLA-DR expression on monocyte and DC subsets in pre-term and full-term neonates, which may contribute to impaired antimicrobial defence mechanisms in the early days of life.
authors.forename: Joerg C
authors.initials: JC
authors.lastname: Schefold
authors.forename: Linn
authors.initials: L
authors.lastname: Porz
authors.forename: Barbara
authors.initials: B
authors.lastname: Uebe
authors.forename: Holger
authors.initials: H
authors.lastname: Poehlmann
authors.forename: Stephan
authors.initials: S
authors.lastname: von Haehling
authors.forename: Andreas
authors.initials: A
authors.lastname: Jung
authors.forename: Nadine
authors.initials: N
authors.lastname: Unterwalder
authors.forename: Christian
authors.initials: C
authors.lastname: Meisel
mesh_terms: D000328:Adult; D003713:Dendritic Cells / Q000145:classification / Q000276:immunology*; D005260:Female; D005865:Gestational Age; D006684:HLA-DR Antigens / Q000097:blood*; D006801:Humans; D007108:Immune Tolerance; D007111:Immunity, Cellular; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood* / Q000276:immunology*; D007239:Infections / Q000097:blood / Q000209:etiology / Q000276:immunology; D008297:Male; D009000:Monocytes / Q000145:classification / Q000276:immunology*; D011247:Pregnancy; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood / Q000276:immunology; D055815:Young Adult
chemical_list: D006684:HLA-DR Antigens