The Body Covers: The 14th Conference on Retroviruses and Opportunistic Infections
Interleukin-2 Expands Select CD4+ T-Cell Populations, but Has No Effect on HIV-Specific Immune Responses
February 26, 2007
Previous studies have shown that the use of interleukin-2 (IL-2) in HIV-infected persons on antiretroviral therapy generally increases naive and central memory CD4+ T cells. The French ANRS 119 study is a randomized trial assessing whether the use of IL-2 in treatment-naive, HIV-infected patients with a CD4+ cell count between 300 and 500 cells/mm3 can prolong the time to antiretroviral therapy initiation by preserving CD4+ cell counts.
A poster presented at the 14th Conference on Retroviruses and Opportunistic Infections summarized the findings from an immunologic substudy of ANRS 119 that evaluated the short-term effects of 4.5 million IU (International Units) of IL-2 twice daily for five days at weeks 0, 8, and 16 on T-cell populations.1 At 24 weeks, the immunologic effects of IL-2 were compared with changes in an untreated control group by examining the quantity of naive (CD45RA+CCR7+), central memory (CD45RA-CCR7+), effector memory (CD45RA-CCR7-), and effector (CD45RA+CCR7-) CD4+ and CD8+ T cells. The levels of these cells were measured using flow immunotyping, while CD4+ and CD8+ T-cell pathogen-specific responses were evaluated using interferon-gamma enzyme-linked immunospot assays.
A total of 26 patients in the IL-2 group and 24 individuals in the control group were included in the substudy analysis. The baseline CD4+ cell counts and viral loads were comparable between the two groups.
These results, coupled with the simian immunodeficiency virus data presented by Louis Picker that highlighted the potential key role of central memory T-cell homeostasis in the pathogenesis of AIDS,2 further raise interest in the final results of several trials that are evaluating the potential clinical benefit of IL-2 in a variety of HIV-infected populations, including ANRS 119 (treatment-naive, HIV-infected individuals), ESPRIT (HIV-infected individuals with a CD4+ cell count greater than 350 cells/mm3) and SILCAAT (HIV-infected individuals with a CD4+ cell count less than 350 cells/mm3). It is hard for me to predict the outcomes of these studies, but the results will likely determine the fate of IL-2 as an immune-based intervention in the treatment of HIV infection.
This article was provided by The Body PRO. Copyright © Body Health Resources Corporation. All rights reserved.