Human Immunodeficiency Virus-Induced Interferon-Stimulated Gene Expression Is Associated With Monocyte Activation and Predicts Viral Load.

BACKGROUND: Chronic immune activation is one of the hallmarks of human immunodeficiency virus (HIV) pathogenesis. Persistent upregulation of interferons (IFNs) and interferon-stimulated genes (ISGs) has previously been associated with chronic immune activation and HIV progression. Here a longitudinal analysis of the IFN and ISG response during HIV infection was performed to gain insights into the ongoing immune activation during HIV infection. METHODS: IFN and ISG levels were determined using quantitative polymerase chain reaction in peripheral blood mononuclear cells of people with HIV at pre-seroconversion, during acute and chronic HIV infection, and during suppressive antiretroviral therapy (ART). RESULTS: HIV infection induced the expression of a set of 4 ISGs-RSAD2, ISG15, IFI44L, and IFI27-which remained upregulated during chronic infection. This set of ISGs showed no clear correlations with T-cell activation as determined by co-expression of CD38 and HLA-DR. However, a strong correlation with monocyte activation marker soluble CD163 in serum was found. Furthermore, the expression of this ISG cluster was predictive of viral load before ART initiation and, on ART, expression levels normalized to pre-seroconversion levels. CONCLUSIONS: The results presented here suggests that ISG expression is linked to monocyte activation, possibly driven by viral replication.