New Approaches For Detecting Recent HIV-1 Infection

Detecting newly HIV-infected people has gained much attention recently for extending the usefulness of HIV testing and surveillance in providing information about HIV incidence, monitoring transmission of uncommon subtypes or drug resistance, and examining possible clinical implications for infected individuals. Recent developments in our ability to detect and distinguish recent and long-term HIV-1 infection using laboratory tests have made the detection of new infections realistic and practical. Sensitive/less-sensitive testing strategy provided a simple laboratory tool (3A11-LS, the detuned assay) to detect recent seroconversion in a cross-sectional population. This approach, termed “Serologic Testing Algorithm for Recent HIV Seroconversionâ€? (STARHS), is based on differential antibody titers in recent versus long-term infections. Additional approaches that rely on different principles and properties of the evolving anti-HIV antibody response, such as antigen or epitope specific antibodies, antibody titers to specific antigen, proportion of HIV-IgG, antibody affinity and conformation dependence of antibodies, are further being investigated. Irrespective of the approach used, our data suggest that an assay that uses antigen(s) derived from a single HIV subtype is likely to have subtype-specific performance. Antigens derived from multiple subtypes will be needed to achieve similar performance among different subtypes. Using a branched gp41 peptide from subtypes B, E, and D, we have recently developed an IgG-capture BED-EIA that detects an increasing proportion of HIV-IgG in total IgG following seroconversion and can be used to detect recent infection. This 96-well EIA has several advantages over previous approaches and should be widely applicable worldwide. The quantitative nature of these assays requires stringent performance criteria that include calibration and quality control reagents. Ongoing research in this area will further enhance our understanding and may expand the use of this approach to alternative specimen types, such as oral fluids and dried blood spots