Close association of CD8+/CD38 bright with HIV-1 replication and complex relationship with CD4+ T-cell count

Area of Science:

• Immunology
• Virology
• Clinical Medicine

Background:

• Lymphocyte activation provides crucial immune monitoring data beyond CD4(+) T-cell counts in HIV-1 infection.
• CD38 is a known T-cell activation marker, with CD8(+)/CD38(bright) specifically identifying activated memory cells.
• This subset offers a potential surrogate gating strategy for immune status assessment.

Purpose of the Study:

• To investigate CD8(+)/CD38(bright) as a marker for HIV-1 immune monitoring.
• To establish cutoff values and assess relationships with HIV-1 viral load (VL) and CD4(+) T-cell counts.
• To evaluate its predictive value for viral load rebound and T-cell depletion.

Main Methods:

• Longitudinal analysis of CD8(+)/CD38(bright) expression in 1,353 HIV-1 infected patients over one year.
• Correlation analysis with HIV-1 RNA viral load and CD4(+) T-cell counts.
• Assessment of predictive accuracy for viral load rebound in aviremic patients on antiviral therapy (ART).

Main Results:

• CD8(+)/CD38(bright) strongly correlated with HIV-1 VL (r=0.87) in non-immunodepressed patients starting ART.
• The marker demonstrated high sensitivity (93%) and specificity (64%) for predicting viral load rebound (>200 copies/ml) in aviremic patients on ART.
• A moderate correlation with CD4(+) T-cell count (r=-0.37) was observed, with dramatic increases in CD8(+)/CD38(bright) during profound CD4(+) T-cell depletion (<50/mm³).

Conclusions:

• CD8(+)/CD38(bright) is an effective marker for monitoring T-cell activation, a key factor in HIV-1 pathogenesis.
• This gating strategy is practical, requiring only a single additional staining in standard CD4 protocols.
• The findings highlight the role of T-cell activation in HIV-1 and suggest additional factors beyond viral replication in immunodepressed individuals.