Increased interleukin-7 plasma levels are associated with recovery of CD4+ T cells in HIV-infected children.
To asses the role of interleukin 7 (IL-7) in the thymic reconstitution of CD4 T cells observed in children after successful antiretroviral therapy, a longitudinal study in five vertically HIV-1-infected children was carried out. Thymic function, IL-7 plasma levels, viral load, and T-lymphocytes subsets were determined every 2 or 3 months for about 90 months. In all the children, the drop in CD4+ T cells below 5-10% was associated with a marked increase in IL-7 plasma levels. The drastic decrease in viral load after treatment, led in all the cases to a recover of CD4 to levels higher than 30%, which was associated to an increase in thymic production of T cells and followed by a decrease in IL-7 to the normal levels. We conclude that the drop in CD4 in HIV children would induce an increase of IL-7 as part of a homeostatic mechanism. IL-7 would induce the thymus to produce new T cells to recover the normal levels of CD4 when the viral load was low and so the thymic function was not inhibited. The increase in the thymic production of new T cells recovers the CD4 population, and leads to a normalization of IL-7 levels.
Department of Immunology, Hospital General Universitario "Gregorio Marañón," Madrid, Spain.
Rafael
R
Correa
Salvador
S
Resino
M Angeles
MA
Muñoz-Fernández
D019380:Anti-HIV Agents / Q000627:therapeutic use; D023241:Antiretroviral Therapy, Highly Active; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005500:Follow-Up Studies; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy / Q000276:immunology* / Q000821:virology; D006801:Humans; D007223:Infant; D015851:Interleukin-7 / Q000097:blood*; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D019562:Viral Load
D019380:Anti-HIV Agents; D015851:Interleukin-7; D018894:Reverse Transcriptase Inhibitors