title: Variation in the IGF-1 gene is associated with lymphocyte subset counts in neonates: the Generation R Study.
abstract: OBJECTIVE
  IGF-1 stimulates growth, development and function of lymphocytes. The aim of this study was to examine whether functional variants of the IGF-1 gene are associated with absolute lymphocyte subset counts in neonates.
  
  
  METHODS
  This study was embedded in the Generation R Study, a prospective cohort study from foetal life onwards. A polymorphism in the IGF-1 promoter region was genotyped in cord blood DNA. Lymphocytes (T, B and NK) and T lymphocyte subsets (helper, cytotoxic, naive and memory) in cord blood were immunophenotyped in 380 neonates by six-colour flow cytometry.
  
  
  RESULTS
  In total, 39% of the neonates were homozygous for the 192-bp allele (wild-type), 48% were heterozygous and 13% were noncarrier. No differences in absolute lymphocyte and T lymphocyte subset counts were observed between the 192-bp allele heterozygous and homozygous groups. In noncarriers, we found 15% lower T lymphocyte (P = 0.03), 22% lower B lymphocyte (P = 0.04) and 10% lower NK lymphocyte counts (P = 0.36) than in the 192-bp allele homozygous group. Analyses of T lymphocyte subsets showed 16% lower helper T lymphocyte counts (P = 0.01) in noncarriers. No significant differences were found for cytotoxic, naive and memory T lymphocyte counts. All associations were adjusted for gravidity, mode of delivery, gestational age, birth weight, gender and 1- and 5- min Apgar scores.
  
  
  CONCLUSIONS
  Our study showed associations between this IGF-1 promoter region polymorphism and absolute lymphocyte subset counts in neonates. These results should be regarded as hypothesis generating until they have been replicated in other studies.
authors.affiliation: The Generation R Study Group, Department of Pediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Duijts
authors.forename: Liesbeth E
authors.initials: LE
authors.lastname: Bakker-Jonges
authors.forename: Dennis O
authors.initials: DO
authors.lastname: Mook-Kanamori
authors.forename: Joost A M
authors.initials: JA
authors.lastname: Labout
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: van Duijn
authors.forename: Jacques J M
authors.initials: JJ
authors.lastname: van Dongen
authors.forename: Herbert
authors.initials: H
authors.lastname: Hooijkaas
authors.forename: Henriëtte A
authors.initials: HA
authors.lastname: Moll
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
mesh_terms: D016175:B-Lymphocyte Subsets / Q000276:immunology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007694:Killer Cells, Natural / Q000276:immunology; D016131:Lymphocyte Subsets / Q000276:immunology*; D008297:Male; D011446:Prospective Studies; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D007334:Insulin-Like Growth Factor I