CD4:CD8 ratio and CD8 count as prognostic markers for mortality in Human Immunodeficiency Virus–infected patients on antiretroviral therapy: The Antiretroviral Therapy Cohort Collaboration (ART-CC).   Clinical Infectious Diseases
Trickey et al. on behalf of the Antiretroviral Therapy Cohort Collaboration aimed to investigate whether the CD4:CD8 ratio or CD8 counts were independently associated with all-cause, AIDS, and non-AIDS mortality in patients treated with antiretroviral therapy (ART) with suppressed viral load and CD4 count >350 cells/μL For the analysis, the authors combined data from 13 European and North American cohorts participating in the Antiretroviral Therapy Cohort Collaboration.
During 276’526 person-years, 1’834 of 49’865 patients (3.7%) died (249 AIDS-related; 1’076 non-AIDS-defining; 509 unknown/unclassifiable deaths). There was little evidence that CD4:CD8 ratio was prognostic for all-cause mortality after adjustment for other factors: the adjusted hazard ratio (aHR) for lower vs middle tertile was 1.11. The association of CD8 count with all-cause mortality was U-shaped with a higher mortality for those with higher and lower values compared with those with values near the median (aHR 1.13 and 1.11, respectively). AIDS related mortality declined with increasing CD4:CD8 ratio and decreasing CD8 count.
In conclusion, the study does not lend strong support to use CD4:CD8 ratio and CD8 count as a prognostic marker for non-AIDS related mortality in virally suppressed patients on ART. However, the failure of many patients in this long-term treated HIV-infected population to reach the levels of CD4:CD8 ratio or CD8 count considered to be normal in the general population may indicate ongoing immune dysregulation. This may have longer-term consequences than the authors have been able to study here, or associations may be only with specific causes of death.