Dynamics and consequences of IL-21 production in HIV-infected individuals: A longitudinal and cross-sectional study

Alexandre Iannello, Mohamed Rachid Boulassel, Suzanne Samarani, Olfa Debbeche, Cécile Tremblay, Emil Toma, Jean Pierre Routy, Ali Ahmad*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

129 Citations (Scopus)


IL-21 is a relatively newly discovered immune-enhancing cytokine that plays an essential role in controlling chronic viral infections. It is produced mainly by CD4+ T cells, which are also the main targets of HIV-1 and are often depleted in HIV-infected individuals. Therefore, we sought to determine the dynamics of IL-21 production and its potential consequences for the survival of CD4+ T cells and frequencies of HIV-specific CTL. For this purpose, we conducted a series of cross-sectional and longitudinal studies on different groups of HIV-infected patients and show in this study that the cytokine production is compromised early in the course of the infection. The serum cytokine concentrations correlate with CD4+ T cell counts in the infected persons. Among different groups of HIV-infected individuals, only elite controllers maintain normal production of the cytokine. Highly active antiretroviral therapy only partially restores the production of this cytokine. Interestingly, HIV infection of human CD4+ T cells inhibits cytokine production by decreasing the expression of c-Maf in virus-infected cells, not in uninfected bystander cells. We also show that the frequencies of IL-21-producing HIV-specific, but not human CMV-specific, Ag-experienced CD4+ T cells are decreased in HIV-infected viremic patients. Furthermore, we demonstrate in this study that recombinant human IL-21 prevents enhanced spontaneous ex vivo death of CD4+ T cells from HIV-infected patients. Together, our results suggest that serum IL-21 concentrations may serve as a useful biomarker for monitoring HIV disease progression and the cytokine may be considered for immunotherapy in HIV-infected patients.

Original languageEnglish
Pages (from-to)114-126
Number of pages13
JournalJournal of Immunology
Issue number1
Publication statusPublished - Jan 1 2010
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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