In many countries outside the United States, decisions on when to start treatment for HIV infection are based on the level of certain white blood cells called CD4+ T cells, which are commonly measured to determine immune health. A study by National Institutes of Health grantees suggests that the best time to start treatment also should be based on how much time has elapsed since becoming HIV-infected. The researchers found that starting treatment within a year of seroconversion--the period within a few weeks of HIV infection when antibodies to the virus are first produced and their concentration reaches a detectable level--can improve immune health.
Sunil Ahuja, M.D., of the Veterans Affairs Center for Personalized Medicine and the University of Texas Health Science Center, and colleagues studied the influence of the duration of time elapsed between HIV infection and treatment initiation on the return of CD4+ T cells to a normal level. The investigators defined "normal" as 900 CD4+ T cells per cubic millimeter, based on previous studies. The level of these cells typically drops substantially in untreated HIV infection. By analyzing data from the ongoing U.S. Military HIV Natural History Study, in which more than 5,000 HIV-infected people are being observed over time, the scientists found that an HIV-infected person's CD4+ T-cell count is more likely to return to normal if treatment starts within a year of seroconversion and at a CD4+ T-cell count of 500 or more.
The researchers also found that achieving a normal CD4+ T-cell count and starting treatment within a year of seroconversion were associated with immune-health benefits. These included a reduction in the risk of developing AIDS, lowering of the inflammatory state of T-cells (which is associated with slower HIV disease progression), and more robust immune responses as manifested by a better antibody response to hepatitis B vaccine. According to the scientists, the study findings may support starting treatment soon after HIV infection while at a relatively high CD4+ T-cell count.
JF Okulicz et al. Influence of the timing of antiretroviral therapy on the potential for normalization of immune status in human immunodeficiency virus 1-infected individuals. JAMA Internal Medicine DOI: 10.1001/jamainternmed.2014.4010 (2014).
Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases, is available for comment.
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