Monocyte turnover predicts speed and severity of AIDS and onset of brain disease

Apr 15, 2010
In healthy individuals, protective white blood cells called monocytes travel from bone marrow to the bloodstream to the brain. Researchers from Boston College, examining the role of monocytes in the progression of AIDS brain disease, show in this image the presence of macrophages -- white blood cells located within tissues -- that are both productively infected with AIDS and cells that are non-productively infected. In this image taken from the brain of a monkey infected with simian immunodeficiency virus, or SIV, the red-colored cells labeled with BrdU+ from the bone marrow, were non-productively infected. Yet they were present in the brain lesion of the animal alongside productively infected green SIVp28 cells and blue CD68+ macrophages. The tracking of the BrdU cells to the SIV brain lesions is a critical finding, placing the non-productively infected cells in sites of active viral replication. Credit: PLoS Pathogens

An increase in the release of monocytes from bone marrow into the bloodstream predicts how rapidly AIDS develops in monkeys and the magnitude of monocyte turnover correlates with the severity of brain disease in AIDS, Boston College researchers report in the current edition of the online journal PLoS Pathogens.

The researchers report the first observation within AIDS of a marker in blood or plasma exclusive to monocytes, which underscores the relationship between innate immune response and the devastating effects of AIDS within the brain. The findings also suggest a potential clinical use of the marker to monitor HIV disease activity, according to Boston College Professor of Biology Kenneth Williams, co-author of the study.

The findings advance the understanding of the role that seemingly protective monocytes play in the deadly progression of HIV and AIDS in the brain, which is an increasingly critical issue. While from AIDS have declined thanks to , AIDS-related dementia remains just as prevalent, particularly as AIDS patients live longer.

that play a critical role in the immune system's response to sickness, monocytes migrate from bone marrow to blood and, in the case of , cross the blood-brain barrier, which normally keeps monocyte levels low in the brains of health individuals. Williams and his lab study monocytes and their more aggressive infection-fighting form, macrophages.

Williams and his co-authors tracked the journey of monocytes by chemically marking the cells to better follow their movement in primates infected with simian (SIV).

The study found that the monocytes that were labeled in the bone marrow, and trafficked through the blood, were found in the brain within SIV lesions. All of the cells with the marker were of a particular subtype of monocyte and macrophage known to be important in amplifying immune responses.

Williams' BC colleague and lead author , Researcher Patricia Burdo, said the study showed the magnitude of cells leaving the bone marrow as seen as marked monocytes predicted which animals would succumb to AIDS rapidly and at death correlated with the severity of SIV .

Correspondingly, the research also revealed the presence of a protein, soluble CD163, that is only made by monocytes, linked to monocyte expansion and therefore predicted disease progression. Burdo said marked monocytes were found in brain lesions, offering further evidence that these infection-fighting blood cells play a role in the damage AIDS does to the brain.

Explore further: Bacterial communities of female genital tract have impact on inflammation, HIV risk

Related Stories

AIDS resistance secret may be in blood

Feb 12, 2007

U.S. scientists say the absence of a specific marker in the blood and tissues of certain monkeys might be part of the key to understanding AIDS resistance.

Unexpected reservoir of monocytes discovered in the spleen

Jul 30, 2009

It takes a spleen to mend a broken heart - that's the conclusion of a surprising new report from researchers at the Massachusetts General Hospital (MGH) Center for Systems Biology, directed by Ralph Weissleder, MD, PhD. ...

Why Some Monkeys Don't Get AIDS

Dec 03, 2009

(PhysOrg.com) -- Two studies published this month in the Journal of Clinical Investigation provide a significant advance in understanding how some species of monkeys such as sooty mangabeys and African green ...

Recommended for you

HIV reservoirs remain obstacles to cure

May 19, 2015

Antiretroviral therapy (ART) has proven lifesaving for people infected with HIV; however, the medications are a lifelong necessity for most HIV-infected individuals and present practical, logistical, economic ...

Microclinics help keep Kenyan HIV patients in care

May 18, 2015

A team led by researchers from UC San Francisco, Organic Health Response, and Microclinic International is reporting results of a study that showed significant benefits of microclinics—an innovative intervention ...

'Redesigned' antibodies may control HIV

May 18, 2015

With the help of a computer program called "Rosetta," researchers at Vanderbilt University have "redesigned" an antibody that has increased potency and can neutralize more strains of the AIDS-causing human ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.