Low plasma human immunodeficiency virus type 2 viral load is independent of proviral load: Low virus production in vivo

Levels of virus in the plasma are closely related to the pathogenicity of h uman immunodeficiency virus type 1 (HIV-1). HIV-2 is much less pathogenic t han HIV-1, and infection with HIV-2 leads to significantly lower plasma vir al load. To identify the source of this difference, we measured both viral RNA and proviral DNA in matched samples from 34 HIV-2-infected individuals. Nearly half had undetectable viral RNA loads (<100 copies/ml), but levels of pro viral DNA were relatively high and confirmed that quantities of prov irus in HIV-1 and HIV-2 infection were similar, Overall, HIV-2 proviral DNA load did not correlate with viral RNA load, and higher viral RNA load was associated with increased production of plasma virus from the proviral temp late, These results suggest that low viral load in HIV-2 infection is due t o decreased rates of viral production, rather than differences in target ce ll infectivity.