Evaluation of the limiting antigen avidity EIA (LAg) in people who inject drugs in Greece

• Published in: Epidemiology and infection Vol. 145; no. 2; pp. 401 - 412
• Main Authors: NIKOLOPOULOS, G. K., KATSOULIDOU, A., KANTZANOU, M., ROKKA, C., TSIARA, C., SYPSA, V., PARASKEVIS, D., PSICHOGIOU, M., FRIEDMAN, S., HATZAKIS, A.
• Format: Journal Article
• Language: English
• Published: England Cambridge University Press 01.01.2017
• Subjects: Acquired immune deficiency syndrome; Adult; AIDS; Antibody Affinity; Antigen Avidity; Antigens; Diagnostic Errors; Drugs; Epidemics; Epidemiology; Female; Greece; HIV; HIV Antibodies - blood; HIV Infections - diagnosis; Human immunodeficiency virus; Humans; Immunoenzyme Techniques - methods; Infections; Intervention; Laboratories; Male; Research centers; RNA, Viral - blood; Substance Abuse, Intravenous - complications; Viral Load; Greece; New York; Athens Greece; Cyprus; United States > US; MED, Greece; Drug injectors; LAg; HIV; incidence; recent infection
• ISSN: 0950-2688; 1469-4409
• DOI: 10.1017/S0950268816002417

This analysis assessed the utility of the limiting antigen avidity assay (LAg). Samples of people who inject drugs (PWID) in Greece with documented duration of HIV-1 infection were tested by LAg. A LAg-normalized optical density (ODn) 41·5 corresponds to a recency window period of 130 days. The proportion true recent (PTR) and proportion false recent (PFR) were estimated in 28 seroconverters and in 366 samples collected >6 months after HIV diagnosis, respectively. The association between LAg ODn and HIV RNA level was evaluated in 232 persons. The PTR was 85·7%. The PFR was 20·8% but fell to 5·9% in samples from treatment-naive individuals with long-standing infection (>1 year), and to 0 in samples with the circulating recombinant form CRF35 AD. A LAg-based algorithm with a PFR of 3·3% estimated a similar incidence trend to that calculated by analyses based on HIV-1 seroconversions. In recently infected persons indicated by LAg, the median log10 HIV RNA level was high (5·30, interquartile range 4·56–5·90). LAg can help identify highly infectious HIV(+) individuals as it accurately identifies recent infections and is correlated with the HIV RNA level. It can also produce reliable estimates of HIV-1 incidence.