Biomarker May Signal HIV Progression

FRIDAY March 28, 2008 -- Researchers at Temple University think they may have found a blood marker that denotes the progression of the virus that causes AIDS.

The researchers found an increase in the CD163+/CD16+ monocyte subset may coincide with the advancement of human immunodeficiency virus (HIV), according to a study published in the March issue of AIDS Research and Human Retroviruses.

"It looks like, based on these correlations, that this particular cell type may be involved in immune impairment and the progression of HIV," Jay Rappaport, a professor of neuroscience and neurovirology who oversaw the study, said in a prepared statement. "Is it a good prognostic indicator? If you have a lot of these monocytes, does it mean you are going to progress into AIDS faster? Right now, all we know is what the correlations are."

A monocyte is a specific white blood cell, a part of the human body's immune system that protects against blood-borne pathogens and moves quickly to sites of infection within the body's tissues. As monocytes enter tissue, they undergo a series of changes.

The researchers investigated these alterations by examining 18 patients with HIV and seven individuals without HIV.

"We did, indeed, find that patients with detectable virus had an increase of this monocyte subset that correlated with the amount of virus they had in their blood," study author Tracy Fischer-Smith, an associate scientist in Temple's Neuroscience Department, said in a prepared statement. "We were surprised to find that in patients with CD4+ T-cell counts of less than 450 cells per microliter [200 or less per microliter is defined as AIDS], the increase of this monocyte subset correlates inversely with the number of T-cells."

Fischer-Smith said this finding suggests that as the monocyte cells are increasing, these patients are losing CD4+ T-cells, which are critical for maintaining one's immune system.

"This may actually provide an earlier window into what is happening with HIV-infected patients where we might be able to see that immune impairment is taking place before we see a dramatic loss of CD4+ T-cells," she said.

The researchers plan to expand this study by following a cohort of patients over time to see if their findings can provide doctors with an early warning system and help them design better therapeutic strategies, Fischer-Smith said.

More information

The U.S. Department of Health and Human Services has more about HIV and AIDS.

Posted: March 2008


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