Impact of CD8+ T-cell activation on CD4+ T-cell recovery and mortality in HIV-infected Ugandans initiating antiretroviral therapy

OBJECTIVES: To assess whether T-cell activation independently predicts the extent of CD4(+) T-cell recovery and mortality in HIV-infected Ugandans initiating antiretroviral therapy (ART). DESIGN: Prospective cohort study. METHODS: HIV-infected adults starting ART and achieving a plasma HIV RNA level (VL) less than 400 copies/ml by month 6 were sampled from the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort in Mbarara, Uganda. CD4 count, VL, and the percentage-activated (CD38(+)HLA-DR(+)) T cells were measured every 3 months. RESULTS: Of 451 HIV-infected Ugandans starting ART, most were women (70%) with median pre-ART values: age, 34 years; CD4 count, 135 cells/μl; and VL, 5.1 log(10) copies/ml. Of these, 93% achieved a VL less than 400 copies/ml by month 6 and were followed for a median of 24 months, with 8% lost to follow-up at 3 years. Higher pre-ART CD8(+) T-cell activation was associated with diminished CD4 recovery after year 1, after adjustment for pre-ART CD4 count, VL, and sex (P = 0.017). Thirty-four participants died, 15 after month 6. Each 10% point increase in activated CD8(+) T cells at month 6 of suppressive ART was associated with a 1.6-fold increased hazard of subsequent death after adjusting for pretherapy CD4 count (P = 0.048). CONCLUSIONS: Higher pre-ART CD8(+) T-cell activation independently predicts slower CD4(+) T-cell recovery and higher persistent CD8(+) T-cell activation during ART-mediated viral suppression independently predicts increased mortality among HIV-infected Ugandans. Novel therapeutic strategies aimed at preventing or reversing immune activation during ART are needed in this setting.