title: Sex differences in HIV RNA level and CD4 cell percentage during childhood.
abstract: BACKGROUND
  HIV-infected women have lower HIV RNA levels and higher CD4-cell counts than do men. This observation has been attributed to the immunomodulatory effects of sex steroid hormones, such as estrogen and progesterone. Limited data exist regarding potential sex differences in HIV RNA level and CD4 parameters among prepubertal children with untreated HIV infection.
  
  
  METHODS
  We examined the relationship of sex to HIV RNA level and CD4 parameters among 670 perinatally HIV-infected, antiretroviral therapy-naive African children aged <18 years (median age, 4.8 years) using multivariate linear regression. In a subset of 188 children, we used longitudinal data to compare changes in HIV RNA levels and CD4 percentage over time. Levels of CD4 and CD8 T-cell activation (CD38+HLA-DR+) were also compared between boys and girls.
  
  
  RESULTS
  Female children had lower HIV RNA levels (P = .0004) and higher CD4 percentages (P < .0001), compared to male children. Multivariate linear regression demonstrated an independent association of sex with both HIV RNA level and CD4 percentages after controlling for other covariates. Multilevel mixed-effects linear regression analysis of longitudinal HIV RNA level and CD4 parameter data showed that sex differences persisted across all observed ages. Levels of T-cell activation did not differ between the sexes.
  
  
  CONCLUSIONS
  Significant sex differences in HIV RNA levels and CD4 parameters are present in HIV-infected children before the onset of puberty. These data suggest that intrinsic genetic differences between male and female individuals, unrelated to sex steroid hormone levels, influence HIV RNA level and CD4 parameters in HIV-infected individuals.
authors.affiliation: Department of Pediatrics, University of California, San Francisco, California, USA.
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Ruel
authors.forename: Brian C
authors.initials: BC
authors.lastname: Zanoni
authors.forename: Isaac
authors.initials: I
authors.lastname: Ssewanyana
authors.forename: Huyen
authors.initials: H
authors.lastname: Cao
authors.forename: Diane V
authors.initials: DV
authors.lastname: Havlir
authors.forename: Moses
authors.initials: M
authors.lastname: Kamya
authors.forename: Jane
authors.initials: J
authors.lastname: Achan
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Charlebois
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Feeney
mesh_terms: D000293:Adolescent; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006678:HIV / Q000235:genetics*; D015658:HIV Infections / Q000097:blood / Q000276:immunology* / Q000821:virology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D017410:Practice Guidelines as Topic; D012367:RNA, Viral / Q000097:blood*; D012737:Sex Factors; D013019:South Africa / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology
chemical_list: D012367:RNA, Viral