Early
CD4 Counts May Predict Immune Recovery
SUMMARY
A higher CD4 cell count when first diagnosed with HIV
infection predicts better immunological recovery after
starting antiretroviral therapy, according to an analysis
of a U.S. military cohort. |
By
Liz Highleyman
 Initiation
of effective combination
antiretroviral therapy typically reduces HIV viral load
to a low or undetectable level and leads to rising CD4 T-cell
levels. Some individuals experience suboptimal CD4 cell gains
and the reasons for this are poorly understood, though research
has shown that people who reach a nadir or lowest-ever CD4 count
below 200 cells/mm3 before starting treatment tend to have poorer
immune recovery.
As reported in the May
4, 2011, advance online edition of the Journal of Acquired
Immune Deficiency Syndromes, Hemant Kulkarni from the
South Texas Veterans Health Care System and colleagues evaluated
the relationship between CD4 cell counts determined soon after
HIV seroconversion, nadir CD4 count, and CD4 cell levels attained
during highly active antiretroviral therapy (HAART).
The analysis included 1085 people with recent infection in the
HIV Natural History Study, a longitudinal cohort of U.S. military
personnel and veterans. Participants started receiving care,
including regular HIV testing, between 1996 and 2008; those
included in the study had a negative test followed by a positive
test (median interval 1.4 years).
The median CD4 cell count at the time of diagnosis was 470 cells/mm3
(above the treatment threshold of 350 cells/mm3 in effect at
the time). The median nadir or lowest CD4 count fell to 311
cells/mm3 prior to treatment initiation. All participants started
HAART, most achieved viral load suppression, and the median
CD4 count after 2 years on treatment rose to 577 cells/mm3.
Results
 |
Participants
with a higher first CD4 T-cell count at or near the time
of HIV seroconversion achieved higher CD4 levels after
starting HAART. |
|
Those
with a first CD4 count above 500 cells/mm3 were 3 times
more likely to again achieve this same level or higher
within 2 years after starting treatment. |
|
This
association was independent of nadir CD4 count before
starting treatment. |
|
Together,
however, baseline and nadir CD4 cell levels strongly predicted
CD4 count after HAART initiation. |
|
Having
a high baseline and lower nadir CD4 count was associated
with maximal immune recovery after starting HAART. |
|
People
with nadir CD4 counts above 200 cells/mm3 had better immunological
recovery on average than those who fell below this level. |
|
The
likelihood of recovering to at least the baseline CD4
count after starting therapy was significantly higher
for participants with a nadir/baseline CD4 cell ratio
that stayed consistently above 0.6 (that is, nadir did
not fall below 60% of baseline level). |
|
Among
people with the same nadir CD4 cell counts, however, having
a higher baseline level at diagnosis was associated with
better immune recovery on HAART. |
Based on these findings, the study authors concluded, "Among
[viral load] suppressing seroconverters, the absolute CD4 T-cell
count attained post-HAART is highly dependent on both baseline
and nadir CD4 T-cell counts."
"These associations further support the early diagnosis
and initiation of HAART among HIV-infected persons," they
recommended, adding that it may be clinically useful to consider
the baseline CD4 count as an "approximate guideline"
for predicting immune recovery during treatment.
Investigator affiliations: Veterans Administration Research
Center for AIDS and HIV-1 Infection, South Texas Veterans Health
Care System, San Antonio, TX; Department of Medicine, University
of Texas Health Science Center, San Antonio, TX; Division of
Biostatistics, University of Minnesota, Minneapolis, MN; Infectious
Disease Clinical Research Program, Uniformed Services University
of the Health Sciences, Bethesda, MD; Infectious Disease Service,
San Antonio Military Medical Center, Brooke Army Medical Center,
Fort Sam Houston, TX; Infectious Disease Clinic, Naval Medical
Center San Diego, San Diego, CA; Infectious Disease Service,
Walter Reed Army Medical Center, Washington, DC; National Institute
for Allergy and Infectious Diseases, National Institutes of
Health, Bethesda, MD; Henry M. Jackson Foundation, Wilford Hall
United States Air Force Medical Center, Lackland Air Force Base,
TX; Division of Epidemiology and Community Health, University
of Minnesota, Minneapolis, MN; Department of Microbiology and
Immunology, and Biochemistry, University of Texas Health Science
Center, San Antonio, TX; Division of Infectious Diseases, Emory
University School of Medicine, Atlanta, GA.
5/20/11
Reference
H
Kulkarni, JF Okulicz, G Grandits, et al. Early Post-Seroconversion
CD4 Cell Counts Independently Predict CD4 Cell Count Recovery
in HIV-1-Postive Subjects Receiving Antiretroviral Therapy.
Journal of Acquired Immune Deficiency Syndromes (abstract).
May 4, 2011 (Epub ahead of print).
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