Signs of immune over-activation has been found in the spinal fluid of volunteers who have suppressed HIV to undetectable levels for four years, according to a newly published study in the Journal of Infectious Diseases. While this did not appear to be linked to a higher risk of central nervous system problems in the patients studied, the authors suggest that ongoing immune activation may contribute to long-term brain injury.   

Arvid Edén, MD, of the department of infectious diseases at the Sahlgrenska Academy at Göteborg University in Göteborg, Sweden, and a team of researchers identified 15 patients on antiretroviral therapy who had maintained an undetectable viral load for more than three and a half years and who’d had their cerebrospinal fluid (CSF) examined by lumbar puncture. The team measured the level of HIV in the CSF as well as neopterin and IgG, which are markers of immune activation. Persistent immune activation is believed by many to be a primary factor in HIV disease progression, and in the brain a cause of brain damage.

All 15 patients maintained undetectable HIV levels for the four-year period and none had development or progression of new brain-related illnesses. Although neopterin and IgG levels also decreased overall during the same period, eight patients had abnormally high levels of both indicators at the four-year mark. Larger and longer-term studies are needed to determine if this level of immune activation could result in future signs of brain injury.