Scientists Spot New Clues to HIV-Linked Dementia

Researchers have identified two genetically distinct types of HIV in the cerebrospinal fluid (CSF) of patients with HIV-associated dementia.   The discovery may help explain why the risk of developing neurological difficulties increases as AIDS patients live longer, and may also help predict which patients are at greatest risk for the problem, according to the U.S. scientists.  They said the two newly-identified HIV types aren’t being detected in HIV that circulates in a patient’s blood, and one type may be present cerebrospinal fluid years before the onset of HIV-linked dementia.  The fact that the two HIV types can be detected in the CSF indicates that they grow in the central nervous system. 

The study, which appears in the journal PLoS Pathogens, was led by researchers at the University of North Carolina at Chapel Hill School of Medicine.

New Mechanism for Dementia?

Hyperactive immune cells that engulf dying and injured cells before they have a chance to recover may contribute to neurodegeneration characteristic of some diseases, posing a previously unreported mechanism for dementia.  Biochemists of the University of California, San Francisco found preliminary evidence for a different pathway of neurodegeneration — one that involves the clearance of apoptotic cells by overly active phagocytic immune cells, such as macrophages, leading to widespread cell loss over time.  Read the full report of this research in PNAS.