Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection

PLoS Pathog. 2016 Jul 14;12(7):e1005661. doi: 10.1371/journal.ppat.1005661. eCollection 2016 Jul.

Abstract

The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed. Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of 'exhaustion' or 'immune checkpoint' markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anti-Retroviral Agents / therapeutic use
  • Antigens, CD / analysis
  • Antigens, CD / biosynthesis
  • Antigens, CD / immunology
  • Biomarkers / analysis*
  • CD8-Positive T-Lymphocytes / immunology*
  • Disease Progression
  • Female
  • Flow Cytometry
  • HIV Infections / drug therapy
  • HIV Infections / immunology*
  • HIV-1*
  • Hepatitis A Virus Cellular Receptor 2 / analysis
  • Hepatitis A Virus Cellular Receptor 2 / biosynthesis
  • Hepatitis A Virus Cellular Receptor 2 / immunology
  • Humans
  • Lymphocyte Activation / immunology
  • Lymphocyte Activation Gene 3 Protein
  • Male
  • Programmed Cell Death 1 Receptor / analysis
  • Programmed Cell Death 1 Receptor / biosynthesis
  • Programmed Cell Death 1 Receptor / immunology

Substances

  • Anti-Retroviral Agents
  • Antigens, CD
  • Biomarkers
  • HAVCR2 protein, human
  • Hepatitis A Virus Cellular Receptor 2
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Lymphocyte Activation Gene 3 Protein