Phenotype and Polyfunctional Deregulation Involving Interleukin 6 (IL-6)- and IL-10-Producing Monocytes in HIV-Infected Patients Receiving Combination Antiretroviral Therapy Differ From Those in Healthy Older Individuals

BACKGROUND

Despite the relevance of monocytes as promoters of the inflammatory response, whether human immunodeficiency virus (HIV) infection induces premature age-related changes to the phenotype and function of monocytes or whether these alterations are different and/or specifically driven by HIV remains to be mechanistically determined.

METHODS

We assayed the activation phenotype and the responsiveness in vitro to Toll-like receptor (TLR) agonists in classical, intermediate, and nonclassical subsets of monocytes by assessing intracellular interleukin 1α (IL-1α), IL-1β, interleukin 6 (IL-6), interleukin 8, tumor necrosis factor α, and interleukin 10 (IL-10) production in 20 HIV-infected patients receiving combination antiretroviral therapy (cART) and 2 groups of uninfected controls (20 age-matched young individuals and 20 older individuals aged >65 years).

RESULTS

HIV-infected patients showed a more activated phenotype of monocytes than older controls. Regarding functionality, under unstimulated conditions HIV-infected patients showed a higher percentage of classical monocytes producing IL-6 and IL-10 than control subjects. The percentage of cells with production of multiple cytokines (polyfunctionality), including IL-10, in response to TLR agonists was greater among HIV-infected patients than among control subjects.

CONCLUSIONS

Inflammatory alterations associated with monocytes during HIV infection are different from those in aging individuals. This monocyte dysfunction, mainly characterized by high levels of IL-6- and IL-10-producing monocytes, may have clinical implications in HIV-infected patients that are different from those in aging individuals.