title: Low monocyte HLA-DR expression as an indicator of immunodepression in very low birth weight infants.
abstract: BACKGROUND
  As a protective response to an inflammatory stimulus, the antigen-presenting molecules (human leukocyte antigen-DR (HLA-DR)) on monocytes are downregulated. If severe, the response may lead to immunodepression or immunoparalysis, associated with an increased rate of morbidity and mortality in adults. In very low birth weight (VLBW) infants, birth and intensive care present major immunological challenges.
  
  
  METHODS
  We measured monocyte HLA-DR expression by flow cytometry and determined 13 plasma cytokines in 56 VLBW infants (gestational age (GA): 23.7-31.8 wk) and 25 controls (GA: 34.1-41.4 wk).
  
  
  RESULTS
  HLA-DR expression decreased postnatally both in VLBW and in control infants. In VLBW infants, GA and respiratory distress syndrome (RDS) both showed associations with HLA-DR nadir on day 3, when 45% of them met the criteria of immunodepression. HLA-DR expression was lower in those infants subsequently developing infection (74 vs. 49% (day 3) and 85 vs. 68% (day 7); both P = 0.002). Interleukin (IL)-6 on day 1 was a predictor of the HLA-DR nadir.
  
  
  CONCLUSIONS
  VLBW infants are in a state of immunodepression postnatally. This immunodepression correlated with GA and was a predisposing factor for late infections. The downregulation of HLA-DR during RDS probably indicates an RDS-induced antigen load on the immune system.
authors.affiliation: Department of Neonatology, Children's Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland. anniina.palojarvi@gmail.com
authors.forename: Anniina
authors.initials: A
authors.lastname: Palojärvi
authors.forename: Jari
authors.initials: J
authors.lastname: Petäjä
authors.forename: Sanna
authors.initials: S
authors.lastname: Siitonen
authors.forename: Cecilia
authors.initials: C
authors.lastname: Janér
authors.forename: Sture
authors.initials: S
authors.lastname: Andersson
mesh_terms: D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D015536:Down-Regulation; D005260:Female; D005434:Flow Cytometry; D005865:Gestational Age; D006684:HLA-DR Antigens / Q000097:blood*; D006801:Humans; D007108:Immune Tolerance; D062071:Infant, Extremely Premature / Q000097:blood / Q000276:immunology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000276:immunology*; D019102:Infant, Very Low Birth Weight / Q000097:blood / Q000276:immunology*; D018836:Inflammation Mediators / Q000097:blood; D007363:Intensive Care Units, Neonatal; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D009000:Monocytes / Q000276:immunology*; D009894:Opportunistic Infections / Q000097:blood / Q000276:immunology; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood / Q000276:immunology; D012307:Risk Factors; D013997:Time Factors
chemical_list: D015415:Biomarkers; D006684:HLA-DR Antigens; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6