Normalization of FoxP3⁺ regulatory T cells in response to effective antiretroviral therapy

Regulatory T cells (Tregs) blunt uncontrolled immune responses. In advanced human immunodeficiency virus (HIV) infection, the total number of Tregs is decreased, but the proportion of T cells with a regulatory phenotype is highly variable. We studied CD4⁺CD25⁺FoxP3⁺ T cells from patients successfully treated with combination antiretroviral therapy (ART). The proportion of CD4⁺CD25⁺FoxP3⁺ cells transiently increased and then decreased from a median of 13% at baseline to 5.1% at 48 weeks, similar to values in normal subjects. These data suggest that with effective therapy, the regulatory cell numbers normalize, and that the inflammatory signals driving their production may also abate.