AIDS - Early CD4 Counts May Predict Immune Recovery

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AIDS - 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 HighleymanInitiation 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 , TX; Department of Medicine, University of Texas Health Science Center, San , 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 Military Medical Center, Army Medical Center, Fort Sam Houston, TX; Infectious Disease Clinic, Naval Medical Center San Diego, San Diego, CA; Infectious Disease Service, Walter Army Medical Center, Washington, DC; National Institute for Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD; Henry M. 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

, TX; Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA.5/20/11

ReferenceH 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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