T Cell Subsets in HIV Infected Patients after Successful Combination Antiretroviral Therapy: Impact on Survival after 12 Years

Objectives: Immune activation is decreased by combination antiretroviral therapy (cART) in patients infected with human immunodeficiency virus (HIV), but residual activation remains and has been proposed as a cause of premature aging and death, but data are lacking. We analyzed the relationship between T-cell subsets after 18 months of cART and overall survival during 12 years of follow up. Methods: A cohort of 101 HIV infected patients who had undetectable plasma HIV after starting cART was included in 1997-1998. T cell subsets were analyzed by flowcytometry after 18 months of cART. Relation to survival was calculated using Kaplan-Meier curves and multiple Cox regression. Results: Seventeen patients died during the observation period. The leading causes of death were non-AIDS cancer and cardiovascular disease. Higher levels of CD8 memory T cells (CD8+, CD45RO+, CD45RA-) showed a significant beneficiary effect on survival, HR of 0.95 (95% confidence interval 0.91-0.99, P = 0.016) when adjusted for age, nadir CD4 count, CD4 count, and AIDS and hepatitis C status. T cell activation was not associated with increased risk of death. Conclusions: Larger and longitudinal studies are needed to accurately establish prognostic factors, but overall results seem to suggest that prognostic information exists within the CD8 compartment.