Researchers at John Hopkins University report that while HIV disease progression is routinely measured by tracking CD4 counts and HIV viral load levels, two other tests may also provide an accurate picture of how quickly HIV is spreading in the body, AIDS Weekly reports. Tests that measure the total lymphocyte counts (TLC) and hemoglobin concentration (Hgb) in the blood also can document the impact of HIV on the immune system, the researchers say. The research data was drawn from a study of nearly 3,300 HIV-positive gay and bisexual men from 1984 to 1991.
Falling TLC and Hgb levels were shown to be associated with HIV disease progression, much the same way falling CD4-cell counts and rising viral loads document the impact of HIV on the body. TLC and Hgb levels tended to remain steady during the first few years of HIV infection among the study subjects but began to plunge rapidly when severe immune system damage started to occur.
"The majority of HIV individuals who develop AIDS experience a rapid decline in total lymphocyte counts and hemoglobin concentration that starts about 1.5 years prior to developing AIDS," the researchers wrote in the journal AIDS. "The decline in these two markers in individuals who develop AIDS shows that this is an important event in the pathogenesis of the disease."
Measuring TLC and Hgb levels may be much easier and cheaper in areas with scarce health resources because the tests are already part of routine blood work, the researchers say, which would eliminate the need to conduct separate blood tests for CD4 counts and HIV viral levels.