title: Reduced thymic size but no evidence of impaired thymic function in uninfected children born to human immunodeficiency virus-infected mothers.
abstract: BACKGROUND
  HIV-exposed, uninfected (HIV-EU) infants present hematologic and immunologic abnormalities at birth, and it remains to be clarified whether these abnormalities persist beyond infancy, for instance, affecting vaccination responses.
  
  
  METHODS
  Thymic size and thymic output were evaluated in 20 HIV-EU children at 15 months of age and compared with 10 age- and gender-matched controls. Regulatory T-cells (Tregs) and immune activation as well as cytokine profiles were determined, and the antibody response to Haemophilus influenzae Type b (Hib) vaccination was evaluated.
  
  
  RESULTS
  Thymic size was significantly lower in HIV-EU children (P = 0.011). However, CD4 and CD8 counts did not differ between HIV-EU and control children. Likewise, thymic output estimated as CD4 cells expressing naive (CD45RA+CD62L+CD27+, P = 0.31) or recent thymic naive (CD45RA+CD27+CD31+, P = 0.13) phenotype, or CD4 cells containing T-cell receptor excision circles (P = 0.47) were comparable. HIV-EU children and controls had similar levels of activated cells (CD4+CD38+HLA-DR+, P = 0.87; CD8+CD38+HLA-DR+, P = 0.22), Tregs (CD4+CD25+CD127(low)FOXP3+, P = 0.53), and naive Tregs (CD4+CD25+CD127(low)FOXP3+CD45RA+CD27+, P = 0.65). Finally, comparable titers of Haemophilus influenzae Type b antibodies in the 2 groups were found (P = 0.43).
  
  
  CONCLUSIONS
  The study demonstrates reduced thymic size in HIV-EU children compared with children born to HIV-negative mothers, but no evidence of impaired thymic function, immune regulation, or antibody vaccination response was detected, suggesting that no qualitative immune deficits persist in HIV-EU children at 15 months of age.
authors.affiliation: Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark. lilian@kolte.dk
authors.forename: Lilian
authors.initials: L
authors.lastname: Kolte
authors.forename: Vibeke
authors.initials: V
authors.lastname: Rosenfeldt
authors.forename: Lena
authors.initials: L
authors.lastname: Vang
authors.forename: Dorthe
authors.initials: D
authors.lastname: Jeppesen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Karlsson
authors.forename: Lars Peter
authors.initials: LP
authors.lastname: Ryder
authors.forename: Kristin
authors.initials: K
authors.lastname: Skogstrand
authors.forename: Susanne
authors.initials: S
authors.lastname: Dam Nielsen
mesh_terms: D000886:Anthropometry; D001284:Atrophy / Q000151:congenital*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006678:HIV; D015658:HIV Infections; D018073:Haemophilus Vaccines / Q000276:immunology; D019741:Haemophilus influenzae type b / Q000276:immunology; D006801:Humans; D007223:Infant; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D013950:Thymus Gland / Q000473:pathology*
chemical_list: D016207:Cytokines; D018073:Haemophilus Vaccines