title: T-lymphocyte subsets in West African children: impact of age, sex, and season.
abstract: OBJECTIVE
  There has been no reference material for T-lymphocyte subsets for normal children in developing countries. We therefore used T-lymphocyte subset determinations among children in three different studies in Guinea-Bissau to construct age-related reference material and to examine possible determinants of T-lymphocyte subset levels.
  
  
  METHODS
  A total of 803 healthy West African children younger than 6 years were included in the three community studies of T-lymphocyte subsets among twins and singletons, after measles infection and after measles immunization. We used the immunoalkaline phosphatase method to determine T-lymphocyte subsets.
  
  
  RESULTS
  We found differences by age, sex, and season, whereas there were no significant differences by birth order, twinning, or ethnic group. The CD4+ percentage declined from birth to age 2 years, at which time it started to increase to higher levels at age 4 to 5 years. The CD8+ percentage increased gradually from early infancy to age 2 to 4 years. The leukocyte count peaked at age 12 to 23 months and declined thereafter, whereas the lymphocyte percentage peaked at age 1 to 5 months and declined gradually thereafter. Compared with dry-season results, the lymphocyte percentage, the absolute lymphocyte count, the absolute CD4+ T-lymphocyte count, and the CD4+/CD8+ ratio were significantly lower during the rainy season, whereas the CD8+ percentage was increased during the rainy season. Girls had higher CD4+/CD8+ ratios and lower CD8+ percentages than did boys.
  
  
  CONCLUSIONS
  Compared with the limited data on T-lymphocyte subsets available from healthy children in developed countries, Guinean children have markedly lower CD4+ percentages and CD4+/CD8+ ratios and higher lymphocyte percentages during the first 2 years of life, when the pressure of infections is particularly high in Africa.
authors.affiliation: Department of Pathology, Hvidovre Hospital, Copenhagen, Denmark.
authors.forename: I M
authors.initials: IM
authors.lastname: Lisse
authors.forename: P
authors.initials: P
authors.lastname: Aaby
authors.forename: H
authors.initials: H
authors.lastname: Whittle
authors.forename: H
authors.initials: H
authors.lastname: Jensen
authors.forename: M
authors.initials: M
authors.lastname: Engelmann
authors.forename: L B
authors.initials: LB
authors.lastname: Christensen
mesh_terms: D000367:Age Factors; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes; D002648:Child; D002675:Child, Preschool; D005260:Female; D006169:Guinea-Bissau; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D018655:Lymphocyte Count; D008297:Male; D012016:Reference Values; D012621:Seasons; D012737:Sex Factors; D016176:T-Lymphocyte Subsets