HIV-1 Viral Replication below 50 Copies/ml in Patients on Antiretroviral Therapy is not associated with CD8 + T-cell Activation

Abstract

Objectives

To determine if the expression of CD38 on CD8⁺ T-cells could be used as a marker of viral replication <50 copies/ml in peripheral blood.

Methods

In a cross-sectional study of patients attending a single HIV clinic in London, an ultra-sensitive HIV RNA viral load assay, with a limit of detection of 3 copies/ml, was used to determine HIV-1 replication in plasma in 70 patients who had sustained viral suppression <50 copies/ml by bDNA assays. Immune activation using the expression of CD38 on CD8⁺ T-cells was also assessed in patients on antiretroviral therapy (ART) with sustained viral suppression, individuals with persistent low-level viraemia <400 copies/ml and subjects failing ART (viral load >400 copies/ml).

Results

There was no significant difference in the percentage of CD8⁺CD38⁺⁺ T-cells between patients with <50 copies or <3 copies/ml. Immune activation was significantly increased in patients with persistent low-level viraemia and in subjects failing ART. CD4⁺ T-cell counts in patients on long-term successful ART are inversely associated with CD8⁺ T-cell activation.

Conclusions

T-cell activation in patients on long-term successful ART is not due to residual low-level viral replication in the blood compartment of HIV-1. CD8⁺ T-cell activation in this patient group appears to be associated with poor CD4⁺ T-cell recovery.