Characterization and determinants of long-term immune recovery under suppressive antiretroviral therapy
Long-term immune recovery is one of the main treatment goals for people with HIV receiving antiretroviral therapy (ART). While most individuals achieve viral suppression, the extent of immune restoration can vary substantially. In the present study published in JAIDS, Turk and Labarile et al. investigated the long-term immune recovery patterns among participants in the Swiss HIV Cohort Study (SHCS) and the Zurich Primary HIV Infection Cohort.
Among 5907 individuals on suppressive ART, the authors modeled CD4 and CD8 T-cell counts and their ratio using nonlinear mixed-effects models to characterize individual immune recovery trajectories. They also examined factors influencing these trajectories and assessed their predictive value for the future occurrence of bacterial pneumonia.
The median plateau CD4 cell count was 718 cells/μL, and the CD4/CD8 ratio approached 1.01, indicating substantial immune recovery in the cohort. Factors such as age, sex, nadir CD4 count, pre-ART viral load, hepatitis C co-infection, ethnicity, HIV acquisition risk, and timing of ART initiation were significantly associated with stronger long-term immune recovery. Notably, individuals with a CD4 plateau in the highest quartile (≥910 cells/μL) had a lower risk of hospitalization due to bacterial pneumonia.
This research provides a detailed characterization of the immune recovery in people with HIV on ART and shows that these recovery properties are strongly linked to risk of bacterial pneumonia. The modeling approach introduced offers a robust framework for future research on immune restoration.