Thymic volume, T-cell populations, and parameters of thymopoiesis in adolescent and adult survivors of HIV infection acquired in infancy.
OBJECTIVE
Antiretroviral therapy has significantly prolonged the lifespan of children who acquire HIV infection in infancy, but the impact of HIV on thymus-mediated maintenance of T lymphocytes has not been studied. To examine the long-term effects of HIV infection in childhood on thymopoiesis, thymic volume and parameters of thymic function from clinically stable adolescents and young adults with HIV infection acquired in infancy were compared with those from uninfected controls.


METHODS
Thymic volume was determined using three-dimensional reconstruction and volumetric analysis of non-contrast enhanced computed tomography images of the upper chest. The degree of fat involution was assessed using a semiquantitive scoring system. CD4 and CD8 T cell populations and T cell receptor recombination excision circles (TREC) concentrations in peripheral blood lymphocytes were measured in all subjects.


RESULTS
Twenty youths (aged 17.6 +/- 2.5 years) with HIV infection acquired perinatally (n = 18) or by neonatal transfusion (n = 2) were enrolled whose HIV plasma viral load had been undetectable for a median of 3.1 years, along with 18 seronegative healthy young adults (aged 20.6 +/- 1.3 years). HIV infected subjects and controls had indistinguishable CD4 T cell counts, thymus volumes (20.5 versus 15.8 cm), thymic index scores, and TREC values. Thymic volume correlated with the number and percentage of CD4 T lymphocytes in the control group and with the number of TREC in CD4 lymphocytes in the HIV infected group.


CONCLUSIONS
Long term survivors of pediatric HIV infection appear to have retained or recovered thymic volume and thymic activity approximating uninfected youths.
Lee
Jason C
JC
David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1721, USA.
Boechat
Maria Ines
MI
Belzer
Marvin
M
Church
Joseph A
JA
De Ville
Jaime
J
Nielsen
Karin
K
Weston
Stephanie
S
Geng
Yongzhi
Y
Dunaway
Theresa
T
Kitchen
Christina
C
Krogstad
Paul A
PA
D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016022:Case-Control Studies; D005260:Female; D019672:Genes, T-Cell Receptor; D015658:HIV Infections / Q000000981:diagnostic imaging / Q000276:immunology* / Q000635:transmission; D006801:Humans; D021621:Imaging, Three-Dimensional; D018445:Infectious Disease Transmission, Vertical; D038041:Lymphopoiesis; D008297:Male; D017741:Survivors; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000000981:diagnostic imaging / Q000276:immunology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed