Avidity Index for Anti-HIV Antibodies: Comparison between Third- and Fourth-Generation Automated Immunoassays

Suligoi, Barbara; Rodella, Anna; Raimondo, Mariangela; Règine, Vincenza; Terlenghi, Luigina; Manca, N.; Casari, Salvatore; Camoni, Laura; Salfa, Maria Cristina; Galli, Claudio

doi:10.1128/jcm.02115-10

Cited by 36 publications

(38 citation statements)

References 16 publications

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“…However, the SAM achieved a lower accuracy than serological HIV-1 incidence assays (2,3,24,25) and demonstrated an inconveniently broad distribution of individual durations of recency. Moreover, the SAM would not be cost-effective if HIV-1 genotyping was performed solely for cross-sectional surveys to estimate HIV-1 incidence.…”

Section: Discussionmentioning

confidence: 99%

“…However, the level and avidity of HIV-specific antibodies increase during the months following seroconversion. This allows recent and nonrecent infections to be distinguished by serology-based HIV-1 incidence assays in which the increase in the proportion of HIV-specific antibodies (2), the avidity of HIV-specific antibodies (3,4), or a combination of HIV-specific antibody level and avidity (5) is measured. Unfortunately, samples from individuals infected with HIV-1 non-B subtypes (6,7), from elite controllers (8), from individuals treated with antiretroviral drugs (8,9), and from individuals with advanced stages of disease (7,9) can be misclassified on the basis of serological criteria because of delayed or reduced production of HIV-specific antibodies.…”

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confidence: 99%

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Assessment of Ambiguous Base Calls in HIV-1 pol Population Sequences as a Biomarker for Identification of Recent Infections in HIV-1 Incidence Studies

et al. 2014

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An increase in the proportion of ambiguous base calls in HIV-1 pol population sequences during the course of infection has been demonstrated in different study populations, and sequence ambiguity thresholds to classify infections as recent or nonrecent have been suggested. The aim of our study was to evaluate sequence ambiguities as a candidate biomarker for use in an HIV-1 incidence assay using samples from antiretroviral treatment-naive seroconverters with known durations of infection (German HIV-1 Seroconverter Study). We used 2,203 HIV-1 pol population sequences derived from 1,334 seroconverters to assess the sequence ambiguity method (SAM). We then compared the serological incidence BED capture enzyme immunoassay (BED-CEIA) with the SAM for a subset of 723 samples from 495 seroconverters and evaluated a multianalyte algorithm that includes BED-CEIA results, SAM results, viral loads, and CD4 cell counts for 453 samples from 325 seroconverters. We observed a significant increase in the proportion of sequence ambiguities with the duration of infection. A sequence ambiguity threshold of 0.5% best identified recent infections with 76.7% accuracy. The mean duration of recency was determined to be 208 (95% confidence interval, 196 to 221) days. In the subset analysis, BED-CEIA achieved a significantly higher accuracy than the SAM (84.6 versus 75.5%, P < 0.001) and results were concordant for 64.2% (464/723) of the samples. Also, the multianalyte algorithm did not show better accuracy than the BED-CEIA (83.4 versus 84.3%, P ‫؍‬ 0.786). In conclusion, the SAM and the multianalyte algorithm including SAM were inferior to the BED-CEIA, and the proportion of sequence ambiguities is therefore not a preferable biomarker for HIV-1 incidence testing.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Assessment of Ambiguous Base Calls in HIV-1 pol Population Sequences as a Biomarker for Identification of Recent Infections in HIV-1 Incidence Studies

et al. 2014

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“…This validation led to the establishment of an assay with an AI cut-off of 40% and a ±10% grey zone, within which samples are retested in duplicate and a final mean AI assigned. The latter step was based on CoV estimates and is in keeping with other published avidity methods (Suligoi et al, 2011;Aghaizu et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Antibody avidity is the binding capacity of maturing antibody to antigen, which increases over time. Various HIV avidity assays have been described including modified commercial assays (Suligoi et al, 2002(Suligoi et al, , 2003Masciotra et al, 2010;Suligoi et al, 2011) and novel avidity assays including the limiting-antigen avidity assay (Doung et al, 2012) and the BioPlex COOH microsphere multiplex assay (Curtis et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Development of an avidity assay for detection of recent HIV infections

Shepherd

McAllister

Kean

et al. 2015

Journal of Virological Methods

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“…33 In that assay, samples are incubated with a chaotropic agent during the initial sample incubation period; in contrast, in the assay described in this report, the chaotropic agent incubation occurs in a separate step, after sample incubation and a wash. In the Abbott Combo-based avidity assay, the FRR was 6.6% after excluding specimens from individuals on ART.…”

Section: Discussionmentioning

confidence: 99%

Development and Evaluation of a Modified Fourth-Generation Human Immunodeficiency Virus Enzyme Immunoassay for Cross-Sectional Incidence Estimation in Clade B Populations

Kirkpatrick

Patel

Celum

et al. 2016

AIDS Research and Human Retroviruses

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Background: Accurate methods for cross-sectional incidence estimation are needed for HIV surveillance and prevention research. We developed an avidity assay based on the fourth-generation Genetic Systems HIV Combo Ag/Ab EIA (Bio-Rad Combo assay) and evaluated its performance. Materials and Methods: The BioRad Combo assay was modified incubating samples with and without 0.025 M diethylamine (DEA). The avidity index (AI) was calculated as the ratio of the DEA-treated to untreated result for a specific sample. We analyzed 2,140 samples from 808 individuals from the United States with known duration of HIV infection. The mean duration of recent infection (MDRI) and the false-recent rate (FRR, fraction of samples from individuals known to be infected >2 years misclassified as recent) were calculated for AI cutoffs of 20%-90% for the avidity assay alone and in combination with a viral load assay (VL, limit of detection 400 copies/ml). Factors associated with misclassification of samples collected ‡2 years after infections were also evaluated. Results: The MDRI for the Bio-Rad Combo Avidity assay ranged from 50 days using an AI cutoff of 20% to 276 days using an AI cutoff of 90%; the FRR ranged from 0% to 9%. When samples with a VL <400 copies/ml were classified as nonrecent, the FRRs were reduced approximately twofold and the MDRI estimates were reduced by *20%. An AI cutoff of 50% provided an MDRI of 135 days with an FRR of 2.1%. All samples from elite suppressors had an AI >80%. In adjusted analysis, viral suppression and low CD4 cell count were significantly associated with misclassification among individuals infected >2 years. Conclusions: This modified Bio-Rad Combo Avidity assay may be a useful tool for cross-sectional HIV incidence estimation. Further research is needed to evaluate use of this assay in combination with other assays to accurately estimate population-level HIV incidence.

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Avidity Index for Anti-HIV Antibodies: Comparison between Third- and Fourth-Generation Automated Immunoassays

Cited by 36 publications

References 16 publications

Assessment of Ambiguous Base Calls in HIV-1 pol Population Sequences as a Biomarker for Identification of Recent Infections in HIV-1 Incidence Studies

Assessment of Ambiguous Base Calls in HIV-1 pol Population Sequences as a Biomarker for Identification of Recent Infections in HIV-1 Incidence Studies

Development of an avidity assay for detection of recent HIV infections

Development and Evaluation of a Modified Fourth-Generation Human Immunodeficiency Virus Enzyme Immunoassay for Cross-Sectional Incidence Estimation in Clade B Populations

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