Reconstitution of Peripheral T Cells by Tissue-Derived CCR4+ Central Memory Cells Following HIV-1 Antiretroviral Therapy

Abstract

Background. Highly active antiretroviral therapy induces clinical benefits to HIV-1 infected individuals, which can be striking in those with progressive disease. Improved survival and decreased incidence of opportunistic infections go hand in hand with a suppression of the plasma viral load, an increase in peripheral CD4+ T-cell counts, as well as a reduction in the activation status of both CD4+ and CD8+ T cells. Methods. We investigated T-cell dynamics during ART by polychromatic flow cytometry in total as well as in HIV-1-specific CD4+ and CD8+ T cells. We also measured gene expression by single cell transcriptomics to assess functional state. Results. The cytokine pattern of HIV-specific CD8+ T cells was not altered after ART, though their magnitude decreased significantly as the plasma viral load was suppressed to undetectable levels. Importantly, while CD4+ T cell numbers increased substantially during the first year, the population did not normalize: the increases were largely due to expansion of mucosal-derived CCR4+ CD4+ TCM; transcriptomic analysis revealed that these are not classical Th2-type cells. Conclusion. The apparent long-term normalization of CD4+ T-cell numbers following ART does not comprise a normal balance of functionally distinct cells, but results in a dramatic Th2 shift of the reconstituting immune system.

Keywords

• Immune reconstitution
• T helper subsets
• Cytokines
• Polarization