Subtype B human immunodeficiency virus (HIV) type 1 mutant that escapes detection in a fourth-generation immunoassay for HIV infection.
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ABSTRACT:
SUBMITTER: Gaudy C
PROVIDER: S-EPMC427870 | biostudies-other | 2004 Jun
REPOSITORIES: biostudies-other
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Project description:BackgroundFourth-generation HIV assays detect both antigen and antibody, facilitating detection of acute/early HIV infection. The Bio-Rad GS HIV Combo Ag/Ab assay (Bio-Rad Combo) is an enzyme immunoassay that simultaneously detects HIV p24 antigen and antibodies to HIV-1 and HIV-2 in serum or plasma.ObjectiveTo evaluate the performance of the Bio-Rad Combo assay for detection of HIV infection in adults from Southern Africa.Study designSamples were obtained from adults in Soweto and Vulindlela, South Africa and Dar es Salaam, Tanzania (300 HIV-positive samples; 300 HIV-negative samples; 12 samples from individuals previously classified as having acute/early HIV infection). The samples were tested with the Bio-Rad Combo assay. Additional testing was performed to characterize the 12 acute/early samples.ResultsAll 300 HIV-positive samples were reactive using the Bio-Rad Combo assay; false positive test results were obtained for 10 (3.3%) of the HIV-negative samples (sensitivity: 100%, 95% confidence interval [CI]: 98.8-100%); specificity: 96.7%, 95% CI: 94.0-98.4%). The assay detected 10 of the 12 infections classified as acute/early. The two infections that were not detected had viral loads<400 copies/mL; one of those samples contained antiretroviral drugs consistent with antiretroviral therapy.ConclusionsThe Bio-Rad Combo assay correctly classified the majority of study specimens. The specificity reported here may be higher than that seen in other settings, since HIV-negative samples were pre-screened using a different fourth-generation test. The assay also had high sensitivity for detection of acute/early infection. False-negative test results may be obtained in individuals who are virally suppressed.
| S-EPMC4319362 | biostudies-literature
Project description:Diagnosis of acute HIV is done by patient history and examination and testing of RNA, proviral DNA, and serology using fourth-generation antigen/antibody detection assays. We describe an HIV-1 primary infection with a second diagnostic window of 18 to 34 days on a fourth-generation immunoassay, which would have been missed using some current algorithms. Caution must be exercised when fourth-generation HIV-1 immunoassays are interpreted in isolation, and additional testing should be considered depending on patient risk assessment.
| S-EPMC4313264 | biostudies-literature
Project description:Early and accurate detection of HIV is crucial when using pre-exposure prophylaxis (PrEP) for HIV prevention to avoid PrEP initiation in acutely infected individuals and to minimize the risk of drug resistance in individuals with breakthrough infection.To determine if fourth-generation antigen/antibody (Ag/Ab) rapid diagnostic tests (RDT) would have detected HIV infection earlier than the third-generation RDT used in MTN-003 (VOICE).5029 VOICE participants were evaluated with third-generation Alere Determine™ HIV-1/2, OraQuick ADVANCE® Rapid HIV-1/2, Uni-Gold™ Recombigen® HIV-1/2 and Bio-Rad GS HIV-1/2+O EIA; and fourth-generation Alere Determine™ HIV-1/2 Ag/Ab Combo, Conformité Européene (CE)-Marked Alere™ HIV Combo and Bio-Rad HIV Combo Ag/Ab EIA. Multispot®, GS HIV-1 Western Blot (WB) and Geenius™ (Bio-Rad) were also evaluated.Of 57 antibody-negative pre-seroconversion plasma samples with HIV RNA >20 copies/mL identified, 16 (28%) were reactive by CE-Marked Alere™ HIV Combo (1 Ab; 9 Ag; 6 Ag/Ab reactive) and 4 (7%) by Alere Determine™ HIV-1/2 Ag/Ab Combo (2 Ab; 2 Ag; 0 Ag/Ab reactive) (p=0.0005). Multispot® confirmed only 1 of 16 acute infections while WB and Geenius™ confirmed none. GS HIV Combo Ag/Ab EIA identified 27 of 57 (47%) pre-seroconversion RNA-positive samples.In VOICE, 28% of infections missed by current third-generation RDT would have been identified with the use of CE-Marked Alere™ HIV Combo. Geenius™, Multispot® and WB were all insensitive (<10%) in confirming infections detected by fourth-generation assays. An improved diagnostic algorithm that includes a fourth-generation RDT with HIV RNA testing will be essential for efficiently identifying seroconverters on PrEP.
| S-EPMC5790424 | biostudies-literature
Project description:BACKGROUND: At least 10% of the 56,000 annual new HIV infections in the United States are caused by individuals with acute HIV infection (AHI). It unknown whether the health benefits and costs of routine nucleic acid amplification testing (NAAT) are justified, given the availability of newer fourth-generation immunoassay tests. METHODS: Using a dynamic HIV transmission model instantiated with U.S. epidemiologic, demographic, and behavioral data, I estimated the number of acute infections identified, HIV infections prevented, quality-adjusted life years (QALYs) gained, and the cost-effectiveness of alternative screening strategies. I varied the target population (everyone aged 15-64, injection drug users [IDUs] and men who have sex with men [MSM], or MSM only), screening frequency (annually, or every six months), and test(s) utilized (fourth-generation immunoassay only, or immunoassay followed by pooled NAAT). RESULTS: Annual immunoassay testing of MSM reduces incidence by 9.5% and costs <$10,000 per QALY gained. Adding pooled NAAT identifies 410 AHI per year, prevents 9.6% of new cases, costs $92,000 per QALY gained, and remains <$100,000 per QALY gained in settings where undiagnosed HIV prevalence exceeds 4%. Screening IDUs and MSM annually with fourth-generation immunoassay reduces incidence by 13% with cost-effectiveness <$10,000 per QALY gained. Increasing the screening frequency to every six months reduces incidence by 11% (MSM only) or 16% (MSM and IDUs) and costs <$20,000 per QALY gained. CONCLUSIONS: Pooled NAAT testing every 12 months of MSM and IDUs in the United States prevents a modest number of infections, but may be cost-effective given sufficiently high HIV prevalence levels. However, testing via fourth-generation immunoassay every six months prevents a greater number of infections, is more economically efficient, and may obviate the benefits of acute HIV screening via NAAT.
| S-EPMC3218000 | biostudies-literature
Project description:BackgroundAccurate 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 methodsThe Bio-Rad 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.ResultsThe 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.ConclusionsThis 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.
| S-EPMC4971410 | biostudies-literature
Project description:Fourth generation (4thG) immunoassay (IA) is becoming the standard HIV screening method but was not available when the Fiebig acute HIV infection (AHI) staging system was proposed. Here we evaluated AHI staging based on a 4thG IA (4thG staging).Screening for AHI was performed in real-time by pooled nucleic acid testing (NAT, n=48,828 samples) and sequential enzyme immunoassay (EIA, n=3,939 samples) identifying 63 subjects with non-reactive 2nd generation EIA (Fiebig stages I (n=25), II (n=7), III (n=29), IV (n=2)). The majority of samples tested (n=53) were subtype CRF_01AE (77%). NAT+ subjects were re-staged into three 4thG stages: stage 1 (n=20; 4th gen EIA-, 3rd gen EIA-), stage 2 (n=12; 4th gen EIA+, 3rd gen EIA-), stage 3 (n=31; 4th gen EIA+, 3rd gen EIA+, Western blot-/indeterminate). 4thG staging distinguishes groups of AHI subjects by time since presumed HIV exposure, pattern of CD8+ T, B and natural killer cell absolute numbers, and HIV RNA and DNA levels. This staging system further stratified Fiebig I subjects: 18 subjects in 4thG stage 1 had lower HIV RNA and DNA levels than 7 subjects in 4thG stage 2.Using 4th generation IA as part of AHI staging distinguishes groups of patients by time since exposure to HIV, lymphocyte numbers and HIV viral burden. It identifies two groups of Fiebig stage I subjects who display different levels of HIV RNA and DNA, which may have implication for HIV cure. 4th generation IA should be incorporated into AHI staging systems.
| S-EPMC3669623 | biostudies-literature
Project description:Recent studies have highlighted the ability of HIV to escape from cytotoxic T lymphocyte (CTL) responses that concurrently target multiple viral epitopes. Yet, the viral dynamics involved in such escape are incompletely understood. Previous analyses have made several strong assumptions regarding HIV escape from CTL responses such as independent or non-concurrent escape from individual CTL responses. Using experimental data from evolution of HIV half genomes in four patients we observe concurrent viral escape from multiple CTL responses during early infection (first 100 days of infection), providing confirmation of a recent result found in a study of one HIV-infected patient. We show that current methods of estimating CTL escape rates, based on the assumption of independent escapes, are biased and perform poorly when CTL escape proceeds concurrently at multiple epitopes. We propose a new method for analyzing longitudinal sequence data to estimate the rate of CTL escape across multiple epitopes; this method involves few parameters and performs well in simulation studies. By applying our novel method to experimental data, we find that concurrent multiple escapes occur at rates between 0.03 and 0.4 day(-1), a relatively broad range that reflects uncertainty due to sparse sampling and wide ranges of parameter values. However, we show that concurrent escape at rates 0.1-0.2 day(-1) across multiple epitopes is consistent with our patient datasets.
| S-EPMC4624722 | biostudies-literature
Project description:Detection of acute HIV infection is critical for HIV public health and diagnostics. Clinical fourth-generation antigen (Ag)/antibody (Ab) combination (combo) and p24 Ag immunoassays have enhanced detection of acute infection compared to Ab-alone assays but require ongoing evaluation with currently circulating diverse subtypes. Genetically and geographically diverse HIV clinical isolates were used to assess clinical HIV diagnostic, blood screening, and next-generation assays. Three-hundred-member panels of 20 serially diluted well-characterized antibody-negative HIV isolates for which the researchers were blind to the results (blind panels) were distributed to manufacturers and end-user labs to assess the relative analytic sensitivity of currently approved and preapproved clinical HIV fourth-generation Ag/Ab combo or p24 Ag-alone immunoassays for the detection of diverse subtypes. The limits of detection (LODs) of virus were estimated for different subtypes relative to confirmed viral loads. Analysis of immunoassay sensitivity was benchmarked against confirmed viral load measurements on the blind panel. On the basis of the proportion of positive results on 300 observations, all Ag/Ab combo and standard sensitivity p24 Ag assays performed similarly and within half-log LODs, illustrating the similar breadth of reactivity and diagnostic utility. Ultrasensitive p24 Ag assays achieved dramatically increased sensitivities, while the rapid combo assays performed poorly. The similar performance of the different commercially available fourth-generation assays on diverse subtypes supports their use in broad geographic settings with locally circulating HIV clades and recombinant strains. Next-generation preclinical ultrasensitive p24 Ag assays achieved dramatically improved sensitivity, while rapid fourth-generation assays performed poorly for p24 Ag detection.
| S-EPMC6062817 | biostudies-other
Project description:We used an allele-specific real-time PCR assay to explore the presence of K103N and M184V minority species among primary human immunodeficiency virus (HIV) infections and their potential influence in HIV transmission. Thirty randomly chosen antiretroviral drug-naive patients lacking both the K103N and the M184V mutations as determined by conventional sequencing methods were studied, and K103N and M184V viral minority species were found in three (10%) and four (11%) patients, respectively.
| S-EPMC2663097 | biostudies-literature
Project description:BackgroundIdentifying immunogens which can elicit effective T cell responses against human immunodeficiency virus type 1 (HIV-1) is important for developing a T-cell based vaccine. It has been reported that human leukocyte antigen (HLA)-B*13-restricted T-cell responses contributed to HIV control in subtype B' and C infected individuals. However, the kinetics of B*13-restricted T-cell responses, viral evolution within epitopes, and the impact on disease progression in CRF01_AE subtype HIV-1-infected men who have sex with men (MSM) are not known.ResultsInterferon-γ ELISPOT assays and deep sequencing of viral RNAs were done in 14 early HLA-B*13-positive CRF01_AE subtype HIV-1-infected MSM. We found that responses to RQEILDLWV (Nef106-114, RV9), GQMREPRGSDI (Gag226-236, GI11), GQDQWTYQI (Pol487-498, GI9), and VQNAQGQMV (Gag135-143, VV9) were dominant. A higher relative magnitude of Gag-specific T-cell responses, contributed to viral control, whereas Nef-specific T-cell responses were associated with rapid disease progression. GI11 (Gag) was conserved and strong GI11 (Gag)-specific T-cell responses showed cross-reactivity with a dominant variant, M228I, found in 3/12 patients; GI11 (Gag)-specific T-cell responses were positively associated with CD4 T-cell counts (R = 0.716, P = 0.046). Interestingly, the GI9 (Pol) epitope was also conserved, but GI9 (Pol)-specific T-cell responses did not influence disease progression (P > 0.05), while a D490G variant identified in one patient did not affect CD4 T-cell counts. All the other epitopes studied [VV9 (Gag), RQYDQILIEI (Pol113-122, RI10), HQSLSPRTL (Gag144-152, HL9), and RQANFLGRL (Gag429-437, RL9)] developed escape mutations within 1 year of infection, which may have contributed to overall disease progression. Intriguingly, we found early RV9 (Nef)-specific T-cell responses were associated with rapid disease progression, likely due to escape mutations.ConclusionsOur study strongly suggested the inclusion of GI11 (Gag) and exclusion of RV9 (Nef) for T-cell-based vaccine design for B*13-positive CRF01_AE subtype HIV-1-infected MSM and high-risk individuals.
| S-EPMC8976269 | biostudies-literature