Abstract and Introduction
Abstract
Patients infected with both viruses had slower disease progression than those infected with HIV-1 only.
Introduction
HIV-1 infection causes most AIDS cases worldwide, but in West Africa, HIV-2 is also prevalent. The natural history of HIV-2 infection tends to be more benign than that of HIV-1, and most patients infected solely with HIV-2 do not progress to AIDS. Previous research suggests that HIV-2 infection protects against subsequent HIV-1 infection and, in cases of dual infection, slows the rate of HIV-1 disease progression. Researchers recently tested this hypothesis using a long-term cohort of untreated individuals infected with one or both viruses.
From 1990 through 2007, all persons employed by the Guinea-Bissau police force were offered enrollment in a prospective study of HIV infection that included blood collection every 12 to 18 months. A total of 223 participants became infected with HIV-1 after enrolling: 191 with HIV-1 only and 32 with both HIV-1 and HIV-2. Of the 32 individuals with dual infection, 20 were infected with HIV-2 first, and 12 had concomitant seroreactivity.
Patients with dual infection had a significantly longer median time to AIDS diagnosis than those infected with HIV-1 only (104 vs. 68 months). They also had a significantly higher mean CD4-cell percentage at the extrapolated time of seroconversion (31% vs. 23%) and a significantly slower increase in CD8-cell percentage over time. Furthermore, their HIV-1 viruses exhibited significantly less genetic diversity over time, which also suggests an attenuating effect of HIV-2 on HIV-1 disease progression. The 20 participants who were infected with HIV-2 before HIV-1 had the longest median time to AIDS diagnosis (129 months) and also the highest mean CD4 percentage at seroconversion (32%).
AIDS Clinical Care © 2012 Massachusetts Medical Society
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