Certain protein patterns in blood cells may indicate that an HIV patient is at risk of dementia, according to a study released Monday. "This study is a first and early work to determine if specific protein fingerprints can be obtained from blood cells that would predict cognitive dysfunction in HIV-1-infected people," said lead investigator Dr. Howard E. Gendelman. Until now, doctors have relied on clinical examinations and brain-imaging techniques to diagnose brain disease, including HIV-associated dementia. The new study offers hope that a blood test may one day help spot early disease.

The researchers used a relatively new technique called proteomics protein fingerprinting to evaluate protein activity in infection-fighting white blood cells. The researchers looked at blood samples from 21 HIV-positive Hispanic women, some with and some without dementia. Their findings were compared to similar blood samples from 10 healthy Hispanic women without HIV.

In all, the team evaluated 177 proteins. Of that group, 38 exhibited different activity levels in women with dementia and those without dementia, according to the report.

"The idea that a blood test can be used with some precision to aid more conventional testing is quite novel and may prove to be important if further defined," said Gendelman. Still, protein patterns may change over time so patients need to be followed, he said. "Groups of proteins may be predictive but others may actually be involved in the disease process," Gendelman said. "Differentiating these groups of proteins is important." "The data is preliminary and much more need[s] to be done before it can be used in any clinical setting," he added.

Another part of this research is equally important, Gendelman said. "It shows that circulating blood cells of the monocyte-macrophage lineage -- the blood's scavenger cells -- are involved in the pathogenic process of disease," he said. "Unlike other types of [brain inflammation] where virus infects nerve cells -- like herpes, and rabies for example -- HIV-1 infects immune cells that enter into the brain and, once inside, cause considerable injury through indirect mechanisms," said Gendelman. If researchers can gain a better understanding of how these indirect mechanisms work, better ways may be found to treat the disease process, he said.

The full report, "Macrophage Proteomic Fingerprinting Predicts HIV-1-Associated Cognitive Impairment," is published in Neurology (2003;60:1931-1937).

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