Sexually transmitted infections and immune activation among HIV-infected but virally suppressed youth on antiretroviral therapy

Background: Human immunodeficiency virus (HIV) infection is associated with chronic immune activation, and concurrent sexually transmitted infections (STIs) may increase immune activation.

Objectives: Because HIV-infected youth are at high risk of STIs and little is known about the impact of STIs on immune activation in HIV-infected youth, we conducted an exploratory study examining the association between STIs and systemic inflammation and immune activation among HIV-infected adolescents.

Study design: Forty-nine behaviorally infected U.S. youth ages 18-24 years with baseline CD4⁺ T-cells >350 who maintained viral suppression on therapy by week 48 were included. Evaluation for STIs (herpes simplex virus [HSV], Chlamydia trachomatis, syphilis, Neisseria gonorrhoeae) was conducted as standard of care and reported on case report forms. Measures of T-cell subsets, systemic immune activation, and soluble factors were examined at week 48 for differences between participants with an STI diagnosis during the 48 weeks compared to those without an STI.

Results: Forty-three participants (88%) were male; 57% had baseline CD4+ T-cell counts >500 cells/mm³. Eighteen youth were reported to have ≥1 STI. At week 48, participants with STIs demonstrated lower CD4⁺ T-cell counts (any STI vs. no STI, p = 0.024; HSV vs. no STI, p = 0.022) and evidence of increased systemic immune activation, including higher CD57 intensity, higher HLA-DR intensity, and lower CD28 percentage, when compared to those without STIs. There were no differences in soluble factors between STI groups.

Conclusions: Results indicate novel activation of CD4⁺ T-cells among HIV-infected youth who have STIs other than HSV, which may contribute to disease progression.