AIDS Weekly (09.29.03) - Friday, October 24, 2003
Currently, physicians track a patient's progression from HIV
to AIDS through HIV RNA and CD4+ cells, expensive measurements
requiring specialized equipment and training. In a recently
published study, researchers from the Johns Hopkins Bloomberg
School of Public Health suggest that a decline in the total
lymphocyte counts (TLC) and hemoglobin (Hgb) concentration in
the blood may be used to monitor a patient's disease status.
"This study demonstrates that there is a biological event that
occurs during the progression of HIV infection leading to
declines in TLC and Hgb within individuals," said lead author
Bryan Lau, a graduate student in the school's department of
epidemiology. "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 decline in these two markers in
individuals who develop AIDS shows that this is an important
event in the pathogenesis of the disease."
The researchers analyzed longitudinal measurements of TLC and
Hgb in 3,299 homosexual and bisexual men enrolled in the
Multicenter AIDS Cohort Study (MACS) from 1984-1991. They
found that for many years after HIV infection, TLC and Hgb
markers remain stable. However, as HIV progresses, TLC and Hgb
begin to rapidly decline. The scientists found a TLC decline
greater than 10 percent per year and an Hgb decline greater
than 2.2 percent per year in 77 percent of study participants
who developed AIDS. Such declines did not occur in more than
78 percent of subjects who did not develop AIDS.
The authors pointed out that current WHO guidelines suggest
using TLC measurements to monitor HIV in developing countries
if CD4+ cell counts are unknown, and that Hgb levels have also
previously been associated with progression from asymptomatic
HIV infection to AIDS.
"These results could be very useful for regions with scarce
health care resources as an alternative way of identifying
individuals who should receive drug therapy for HIV
infection," said Joseph Margolick, a coauthor of the study and
professor in the school's department of molecular microbiology
and immunology. "We believe further research in appropriate
populations is warranted."
The report, "Rapid Declines in Total Lymphocyte Counts and
Hemoglobin Concentration Prior to AIDS Among HIV-1 Infected
Men," appeared in the journal AIDS (2003;17(14):2035-2044).