An October 2011 study revealed a novel characteristic of HIV—it
can replicate, or make new copies of itself in macrophages,
cells in the immune system. This revelation is shedding light on
why some patients develop a type of dementia linked to HIV
despite receiving antiretroviral therapy. The study, published
in the online journal PLoS Pathogens, was conducted by
researchers at the University of North Carolina at Chapel Hill
School of Medicine. Collaborators from the University of
California, San Francisco (UCSF) supplied samples of blood and
cerebrospinal fluid (CSF) from eight HIV patients with
HIV-1-associated dementia (HAD) or other neurological
complications. The investigators discovered the existence of two
variants of HIV in the CSF of HAD patients, which were not
detectable in HIV circulating in the blood. One variant
reproduced in CD4+ T cells (commonly called CD4 cells),
lymphocytes in the immune system that bind HIV, allowing it a
point of entry into the body. The other variant replicated in
macrop