Performance of Bio-Rad and Limiting Antigen Avidity Assays in Detecting Recent HIV Infections Using the Quebec Primary HIV-1 Infection Cohort

Abstract

BackgroundAccurate and practical biologic tools to estimate HIV incidence is crucial to better monitor the epidemic and evaluate the effectiveness of HIV prevention and treatment programs.MethodsWe evaluated two avidity assays to measure recent HIV infection: the Sedia HIV-1 LAg-Avidity EIA (Sedia Biosciences, Portland) and the Centers for Disease Control and Prevention (CDC)-modified Bio-Rad-Avidity assay (Bio-Rad Laboratories, Mississauga, ON). Longitudinal specimens (n = 473) obtained from 123 treatment-naive seroconverted individuals enrolled in the Primary HIV-1 Infection (PHI) cohort of Quebec were used to determine the average time an individual is considered to be recently infected (mean duration of recent infection; MDRI), for the two avidity assays alone and in combination using a nonparametric survival method analysis. A total of 420 specimens from individuals with established HIV infection (90 individuals from the PHI cohort of Quebec and 330 individuals from the Laboratoire de santé publique du Quebec (LSPQ) serobank) were also tested to investigate false recency rate (FRR).ResultsThe CDC-modified Bio-Rad-Avidity gave an estimated MDRI of 234 days (95% CI 220–249) at the avidity index cutoff of 30% while the Sedia-LAg-Avidity assay gave an estimated MDRI of 120 days (95% CI 109–132) at the normalized optical density (ODn) cutoff of 1.5. The FRR among individuals with established HIV infection was 10.2% (7.5%-13.5%) with the CDC-modified Bio-Rad-Avidity assay as compared to 6.0% (3.9%-8.7%) with the Sedia-LAg-Avidity assay. When optimizing a multiassay algorithm (MAA) that includes sequentially the CDC-modified Bio-Rad-Avidity assay then the Sedia-LAg-Avidity assay EIA (avidity index/ODn: 30%/1.7), the MDRI was 136 days (95% CI 123–148) and the FRR, 3.3% (95% CI 1.8–5.6).ConclusionMultiassay algorithms that include the CDC-modified Bio-Rad-Avidity assay and the Sedia-LAg-Avidity assay performed better than each avidity assay alone. Such 2-assay algorithm that starts with the CDC-modified Bio-Rad-Avidity assay followed by the Sedia-LAg-Avidity assay allowed a better classification of HIV-1 infections.

HIV-1 envelope sequence-based diversity measures for identifying recent infections

“…In the province of Québec (Canada), all serum samples that are repeatedly reactive using a screening HIV-1,2 enzyme immunoassay (EIA) are submitted to the provincial reference microbiology laboratory “(Laboratoire de Santé publique du Québec (LSPQ)” for confirmation mainly via a HIV-1 Western blot (WB) and/or HIV-1 p24 EIA. Western blot positive samples are submitted to a multi-assay algorithm (MAA) that combines a Centers for Disease Control and Prevention (CDC) modified Bio-Rad-Avidity assay followed by the Sedia-LAg-Avidity assay [ 24 ]. This MAA previously demonstrated good performance for identifying recent HIV-1 infections, showing a false recent rate (FRR) of 3.3% for a mean duration of recent infection (MDRI) of 136 days [ 24 ].…”

“…A multi-assay based serological algorithm based on two commercially available avidity assays [ 24 ] was recently developed in our laboratory. It has been shown to provide good discriminatory power to identify individuals infected within 136 days mean duration of recent infection (MDRI), with an estimated false recency rate of 3.3% [ 24 ].…”

“…A multi-assay based serological algorithm based on two commercially available avidity assays [ 24 ] was recently developed in our laboratory. It has been shown to provide good discriminatory power to identify individuals infected within 136 days mean duration of recent infection (MDRI), with an estimated false recency rate of 3.3% [ 24 ]. This algorithm was used in the present study to classify clinical specimens as recently infected individuals (MDRI < 136 days) or chronically infected individuals (>136 days) [ 24 ].…”

“…It has been shown to provide good discriminatory power to identify individuals infected within 136 days mean duration of recent infection (MDRI), with an estimated false recency rate of 3.3% [ 24 ]. This algorithm was used in the present study to classify clinical specimens as recently infected individuals (MDRI < 136 days) or chronically infected individuals (>136 days) [ 24 ]. Finally, a variety of molecular-based assays monitoring the HIV-1 viral genetic diversity throughout disease progression have been described, including: 1) The High Resolution Melting Assay (HRM), which evaluates the melting temperatures of HIV amplicons to estimate the number of HIV-1 quasi-species present in a given individual specimen [ 36 – 38 ]; 2) the number of ambiguous nucleotides (mixed bases) [ 17 , 39 ], for which DNA sequences are usually provided by first generation sequencing; 3) the Hamming Distance (HD), which measures points of variation between two sequences of equal length [ 40 , 41 ] using first generation sequencing; and 4) sequence-based diversity measurements as assessed by next generation sequencing (NGS) [ 42 , 43 ], which is able to detect minor variants/mutations at low rates [ 44 ].…”

Characterization of Humoral Immune Responses against Capsid Protein p24 and Transmembrane Glycoprotein gp41 of Human Immunodeficiency Virus Type 1 in China

“…A more practical approach is to implement incidence assays in a cross-sectional study [8–10]. However, the independent evaluation in specimen panels developed by the consortium for the evaluation and performance of HIV incidence assays (CEPHIA) showed that the current incidence assays did not reach the criteria of large mean duration of recent infection (MDRI) and small false-recent rate (FRR) for distinguishing recent and long-term HIV-1 infection [11].…”