A study published in the journal Nature Communications on July 27, 2026, found that HIV-specific immune activity persists in the central nervous system (CNS) of South African adolescents living with HIV, even when the virus is suppressed in the blood by antiretroviral therapy (ART). The research, led by scientists from the University of Cape Town and the University of California, San Francisco, followed 159 adolescents born with HIV who started ART in infancy.
The participants, part of the Cape Town Adolescent Antiretroviral Cohort, had a median age of 15.3 years and had been on ART for a median of 13.1 years. Despite having undetectable viral loads in blood for a median of 8.5 years, 42% showed evidence of HIV-specific T-cell responses in cerebrospinal fluid (CSF), indicating ongoing immune recognition of the virus in the CNS. The study used lumbar punctures to collect CSF samples, a procedure that was well-tolerated by participants.
Lead author Dr. Helen G. Durand stated, 'Our findings suggest that the CNS may serve as a reservoir for HIV, even when the virus is well-controlled in the blood. This has implications for long-term neurological health and the development of cure strategies.' The researchers noted that higher levels of CNS immune activation were associated with lower performance on cognitive tests, though the clinical significance remains under investigation.
The study was funded by the U.S. National Institutes of Health and the South African Medical Research Council. It highlights the need for ongoing monitoring of CNS health in people living with HIV, even those with sustained viral suppression. The authors call for further research into whether ART regimens can be optimized to better target the CNS.
