Predictors of CD4:CD8 ratio normalization and its effect on health outcomes in the era of combination antiretroviral therapy

Abstract

Background: HIV leads to CD4:CD8 ratio inversion as immune dysregulation progresses. We examined the predictors of CD4:CD8 normalization after combination antiretroviral therapy (cART) and determined whether normalization is associated with reduced progression to AIDS-defining illnesses (ADI) and death.

Methods: A Canadian cohort of HIV-positive adults with CD4:CD8<1.2 prior to starting cART from 2000-2010 were analyzed. Predictors of (1) reaching a CD4:CD8 ≥ 1.2 on two separate follow-up visits >30 days apart, and (2) ADI and death from all causes were assessed using adjusted proportional hazards models.

Results: 4206 patients were studied for a median of 2.77 years and 306 (7.2%) normalized their CD4:CD8 ratio. Factors associated with achieving a normal CD4:CD8 ratio were: baseline CD4+ T-cells >350 cells/mm(3), baseline CD8+ T-cells <500 cells/mm(3), time-updated HIV RNA suppression, and not reporting sex with other men as a risk factor. There were 213 ADIs and 214 deaths in 13476 person-years of follow-up. Achieving a normal CD4:CD8 ratio was not associated with time to ADI/death.

Conclusions: In our study, few individuals normalized their CD4:CD8 ratios within the first few years of initiating modern cART. This large study showed no additional short-term predictive value of the CD4:CD8 ratio for clinical outcomes after accounting for other risk factors including age and HIV RNA.

Figure 1. Kaplan-Meier curves of time to CD4:CD8 normalization by: (a) baseline CD4+ T-cells; (b) baseline CD8+ T-cells.

Figure 2. Kaplan-Meier curves of time to AIDS-defining illness or death by time updated: a) CD4:CD8 normalization; b) virologic suppression; c) stratification among 4 groups according to CD4:CD8 normalization, viral load suppression, both, and neither.