HIV-associated dementia complex, termed HIV encephalitis, occurs in about one-quarter of infected individuals. Unfortunately, the symptoms and signs of dementia are not usually evident until the late stages of encephalitis, after irreversible damage has occurred. Thus, diagnostic tools for the detection of HIV encephalitis prior to the manifestation of neurological signs would greatly aid in developing therapeutic intervention. Clayton A. Wiley and colleagues, from Presbyterian University Hospital, have tested the use of PET scans to detect and monitor HIV encephalitis progression (pages 981–989). Using a macaque model, they administered radiolabeled ligands for the peripheral benzodiazepine receptor (PBR), which is abundantly expressed on brain macrophages, and used PET imaging to monitor macrophage infiltration in simian immunodeficiency virus–infected (SIV-infected) macaques. They detected increased ligand binding only in the brains of SIV-infected macaques that developed encephalitis. Moreover, histopathological studies enabled them to correlate various stages of SIV encephalitis with levels of radiolabel uptake and binding, indicating that PET scans can be used to observe progression of the disease in addition to facilitating early detection. The development of such diagnostic tools will be of great importance in the care and treatment of HIV-infected patients.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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