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The newspaper of The Johns Hopkins University September 15, 2003 | Vol. 33 No. 3
Study: AIDS Development Can be Monitored and Predicted

By Kenna Brigham
School of Public Health

People with HIV and their physicians could have a less expensive tool to track the progression from HIV infection to AIDS. According to researchers from the Johns Hopkins Bloomberg School of Public Health, a decline in the total lymphocyte counts, or TLC, and hemoglobin concentration in the blood may be used to monitor a patient's disease status.

Currently, HIV RNA and CD4+ cells in the blood are measured, but specialized equipment and training for lab technicians makes these measurements expensive. TLC and hemoglobin measurements are much less expensive and can be obtained by using standard blood tests. The study, "Rapid declines in total lymphocyte counts and hemoglobin concentration prior to AIDS among HIV-1-infected men," appears in the September issue of AIDS, the journal of the International AIDS Society.

According to lead author Bryan Lau, a graduate student in the Department of Epidemiology, "This study demonstrates that there is a biological event that occurs during the progression of HIV infection leading to declines in TLC and hemoglobin within individuals. The majority of HIV individuals who develop AIDS experience a rapid decline in total lymphocyte counts and hemoglobin concentration that starts about one and one half years prior to developing AIDS," he said. "The decline in these two markers in individuals who develop AIDS shows that this is an important event in the pathogenesis of the disease."

The authors analyzed longitudinal measurements of TLC and hemoglobin in 3,299 homosexual and bisexual men enrolled in the Multicenter AIDS Cohort Study from 1984 through 1991. The researchers found that for many years after HIV infection, TLC and hemoglobin markers are stable and provide little information about HIV disease progression to AIDS.

However, as HIV disease progresses, TLC and hemoglobin begin to decline rapidly. A TLC decline greater than 10 percent per year and hemoglobin decline greater than 2.2 percent per year was present in more than 77 percent of the study participants who developed AIDS and absent from more than 78 percent of individuals who did not develop AIDS.

To further support their findings, the researchers explained in their study that current World Health Organization guidelines suggest the use of TLC measurements for monitoring an individual's HIV infection in developing countries if CD4+ cell counts are not known. Hemoglobin levels also have been shown to have an association with progression from asymptomatic HIV infection to AIDS.

Currently, in order to begin antiretroviral therapy for asymptomatic HIV-infected individuals, measurements of HIV RNA levels and CD4+ lymphocyte counts in the blood are required. These measurements are expensive and require technological expertise and equipment that is typically not available in developing countries.

Contributing author Joseph Margolick, a professor in the Department of Molecular Microbiology and Immunology, said, "These results could be very useful for regions with scarce heath care resources as an alternative way of identifying individuals who should receive drug therapy for HIV infection. We believe further research in appropriate populations is warranted."

Stephen J. Gange, an adjunct associate professor in the Department of Epidemiology, was also a co-author of the study.

The Multicenter AIDS Cohort Study is funded by the National Institute of Allergy and Infectious Diseases and the National Cancer Institute.


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