HIV-induced T-cell activation/exhaustion in rectal mucosa is controlled only partially by antiretroviral treatment

PLoS One. 2012;7(1):e30307. doi: 10.1371/journal.pone.0030307. Epub 2012 Jan 19.

Abstract

Peripheral blood T-cells from untreated HIV-1-infected patients exhibit reduced immune responses, usually associated with a hyperactivated/exhausted phenotype compared to HAART treated patients. However, it is not clear whether HAART ameliorates this altered phenotype of T-cells in the gastrointestinal-associated lymphoid tissue (GALT), the main site for viral replication. Here, we compared T-cells from peripheral blood and GALT of two groups of chronically HIV-1-infected patients: untreated patients with active viral replication, and patients on suppressive HAART. We characterized the T-cell phenotype by measuring PD-1, CTLA-4, HLA-DR, CD25, Foxp3 and granzyme A expression by flow cytometry; mRNA expression of T-bet, GATA-3, ROR-γt and Foxp3, and was also evaluated in peripheral blood mononuclear cells and rectal lymphoid cells. In HIV-1+ patients, the frequency of PD-1(+) and CTLA-4(+) T-cells (both CD4+ and CD8+ T cells) was higher in the GALT than in the blood. The expression of PD-1 by T-cells from GALT was higher in HIV-1-infected subjects with active viral replication compared to controls. Moreover, the expression per cell of PD-1 and CTLA-4 in CD4(+) T-cells from blood and GALT was positively correlated with viral load. HAART treatment decreased the expression of CTLA-4 in CD8(+) T cells from blood and GALT to levels similar as those observed in controls. Frequency of Granzyme A(+) CD8(+) T-cells in both tissues was low in the untreated group, compared to controls and HAART-treated patients. Finally, a switch towards Treg polarization was found in untreated patients, in both tissues. Together, these findings suggest that chronic HIV-1 infection results in an activated/exhausted T-cell phenotype, despite T-cell polarization towards a regulatory profile; these alterations are more pronounced in the GALT compared to peripheral blood, and are only partiality modulated by HAART.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / therapeutic use
  • Antiretroviral Therapy, Highly Active
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / metabolism
  • CTLA-4 Antigen / metabolism
  • Female
  • Flow Cytometry
  • Forkhead Transcription Factors / metabolism
  • Granzymes / metabolism
  • HIV Infections / drug therapy
  • HIV Infections / immunology*
  • HIV Infections / physiopathology*
  • HLA-DR Antigens / metabolism
  • Humans
  • Interleukin-2 Receptor alpha Subunit / metabolism
  • Lymphocyte Activation / drug effects
  • Lymphoid Tissue / drug effects
  • Lymphoid Tissue / metabolism
  • Male
  • Middle Aged
  • Mucous Membrane / drug effects
  • Mucous Membrane / metabolism
  • Programmed Cell Death 1 Receptor / metabolism
  • Rectum / cytology*
  • T-Lymphocytes / drug effects*
  • T-Lymphocytes / metabolism*

Substances

  • Anti-HIV Agents
  • CTLA-4 Antigen
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • HLA-DR Antigens
  • Interleukin-2 Receptor alpha Subunit
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Granzymes