Quantification of naive and memory T-cell turnover during HIV-1 infection.
Level 3 - non-randomized controlled study
Small non-randomized controlled observational kinetic study comparing HIV-1 patients and healthy controls
PubMed 26213901 · doi:10.1097/QAD.0000000000000822
What was done
Long-term in-vivo heavy water (2H2O) labeling combined with mathematical modeling was used to estimate average lifespans of naive and memory CD4 and CD8 T cells in untreated HIV-1 infection (n = 4), combination antiretroviral therapy (cART)-treated individuals with normal-range CD4 counts (n = 3), and healthy controls (n = 5).
What was found
In untreated HIV-1 infection, average lifespans were 618 days for naive CD4, 271 days for naive CD8, 53 days for memory CD4, and 43 days for memory CD8 T cells—all at least three-fold shorter than in healthy controls. In patients on effective cART, memory T-cell turnover nearly normalized, but naive CD4 and CD8 T-cell lifespans remained two-fold shorter than normal.
Why it matters
This provides direct in vivo kinetic evidence that accelerated turnover spans both naive and memory T-cell compartments in HIV-1 infection, and demonstrates that naive T-cell kinetic abnormalities persist even when circulating CD4 counts normalize under effective antiretroviral treatment.
Limits
The sample size is very small (total n = 7 HIV-infected subjects and 5 controls), limiting statistical power and generalizability. Kinetic parameters rely on mathematical modeling of labeling curves, and the abstract does not report variance metrics or clinical outcome correlates.
Cited by
- contradicts The human immune system turns over entirely every 120 days.