Older age and HIV status independently affect an individual’s immune system. Yet, there is no evidence that HIV infection and advancing age together accelerate changes in age-related T-cell markers, according to a new study.
“Using a large cohort of virally suppressed HIV-infected individuals and demographically matched uninfected individuals over a broad range of ages, this paper aimed to explore whether HIV, in the setting of optimal viral suppression, accelerates the changes seen with normal aging of the immune system,” said Brinda Emu, MD, an assistant professor of medicine at the Yale School of Medicine, in New Haven, Conn.
Dr. Emu and colleagues used data from the Veterans Aging Cohort Study to analyze 111 HIV-infected and 114 uninfected patients from 2005 to 2007 (J Acquir Immune Defic Syndr 2017 Nov. 13. [Epub ahead of print]). All of the HIV-infected individuals were receiving antiretroviral therapy and had a viral load of less than 400 copies/mL for at least three years.
The researchers examined T-cell markers with flow cytometry, and used multivariate linear regression to evaluate what effect, if any, HIV and age had on T-cell phenotypes.
“We found that both age and HIV have effects, but that there was no evidence that one increases the effects of the other,” Dr. Emu said.
Both HIV infection and increasing age were found to be associated with fewer CD4+ T cells (P=0.014) and CD8+ T cells (P<0.0001) in all subjects. Similarly, both characteristics were associated with higher proportions of effector memory CD4+ T cells (P<0.0001 for HIV infection; P=0.04 for age) and CD8+ T cells (P=0.0001 for HIV infection; P=0.0004 for age).
Although HIV-infected individuals had a higher proportion of activated CD8+ T cells (P<0.0001), advancing age did not cause a similar rise.
Ultimately, the researchers concluded that no significant interactions could be found between HIV infection and age.
“It is important to highlight this lack of synergy because we find no evidence of a biologic interaction of HIV infection and age on these parameters among virally suppressed individuals,” Dr. Emu said. “This finding becomes particularly critical when defining the best approaches for combatting age-associated clinical conditions in this population.”
By Ethan Covey