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Oliver Laeyendecker - One of the best experts on this subject based on the ideXlab platform.
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sars cov 2 antibody Avidity responses in covid 19 patients and convalescent plasma donors
The Journal of Infectious Diseases, 2020Co-Authors: Sarah E Benner, Oliver Laeyendecker, Eshan U Patel, Andrew Pekosz, Kirsten Littlefield, Yolanda Eby, Reinaldo E Fernandez, Jernelle Miller, Charles S KirbyAbstract:BACKGROUND: Convalescent plasma therapy is a leading treatment for conferring temporary immunity to COVID-19-susceptible individuals or for use as post-exposure prophylaxis. However, not all recovered patients develop adequate antibody titers for donation and the relationship between Avidity and neutralizing titers is currently not well understood. METHODS: SARS-CoV-2 anti-spike and anti-nucleocapsid IgG titers and Avidity were measured in a longitudinal cohort of COVID-19 hospitalized patients (nâ =â 16 individuals) and a cross-sectional sample of convalescent plasma donors (nâ =â 130). Epidemiologic correlates of Avidity were examined in donors by linear regression. The association of Avidity and a high neutralizing titer (NT) were also assessed in donors using modified Poisson regression. RESULTS: Antibody Avidity increased over duration of infection and remained elevated. In convalescent plasma donors, higher levels of anti-spike Avidity were associated with older age, male sex, and hospitalization. Higher NTs had a stronger positive correlation with anti-spike IgG Avidity (Spearman ρ = 0.386; Pâ <â .001) than with anti-nucleocapsid IgG Avidity (Spearman ρ = 0.211; Pâ =â .026). Increasing levels of anti-spike IgG Avidity were associated with high NT (≥160) (adjusted prevalence ratioâ =â 1.58 [95% confidence intervalâ =â 1.19-2.12]), independent of age, sex, and hospitalization. CONCLUSIONS: SARS-CoV-2 antibody Avidity correlated with duration of infection and higher neutralizing titers, suggesting a potential alternative screening parameter for identifying optimal convalescent plasma donors.
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validation of the limiting antigen Avidity assay to estimate level and trends in hiv incidence in an a d epidemic in rakai uganda
AIDS Research and Human Retroviruses, 2019Co-Authors: Ronald H Gray, Oliver Laeyendecker, Mary K Grabowski, Steven James Reynolds, Anthony Ndyanabo, Joseph Ssekasanvu, Reinaldo Fernandez, Maria J WawerAbstract:Abstract The limiting-antigen Avidity (LAg-Avidity) assay with viral load (VL) >1,000 copies/mL is being used to estimate population-level HIV incidence in Africa. However, this has not been valida...
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short communication the impact of viral suppression and viral breakthrough on limited antigen Avidity assay results in individuals with clade b hiv infection
AIDS Research and Human Retroviruses, 2016Co-Authors: Sarah K Wendel, Andrew F Longosz, Thomas C Quinn, Susan H Eshleman, Oliver Laeyendecker, Richard D Moore, Joel N Blankson, Jeanne C KerulyAbstract:We analyzed the impact of HIV viral load on the performance of a limiting antigen Avidity enzyme immunoassay (LAg-Avidity assay) and determined if this assay could be used to identify viral breakthrough. Three groups of samples were tested: (1) 18 individuals (30 samples) previously identified as elite suppressors; (2) 18 individuals (72 samples) who were continually suppressed on antiretroviral treatment (ART) with 1 sample before and 2-6 samples (one/year) after ART initiation; and (3) 20 individuals (179 samples) on ART who had evidence of viral breakthrough (>400 copies/ml) with subsequent viral suppression. Elite suppressors had the lowest LAg-Avidity assay values. Among those who were continually suppressed on ART, 83% (15/18) had LAg-Avidity assay values that decreased over time. Although the LAg-Avidity assay on a single sample cannot identify when a viral breakthrough occurs, paired longitudinal samples could identify viral breakthrough (sensitivity: 65%, specificity: 84%).
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impact of hiv subtype on performance of the limiting antigen Avidity enzyme immunoassay the bio rad Avidity assay and the bed capture immunoassay in rakai uganda
AIDS Research and Human Retroviruses, 2014Co-Authors: Andrew F Longosz, David Serwadda, Fred Nalugoda, Godfrey Kigozi, Veronica Franco, Ronald H Gray, Thomas C Quinn, Susan H Eshleman, Oliver LaeyendeckerAbstract:Abstract Previous studies demonstrated that individuals with subtype D HIV infection who had been infected for 2 or more years were frequently misclassified as assay positive using cross-sectional incidence assays. Samples from 510 subjects (212 subtype A, 298 subtype D) who were infected for 2.2 to 14.5 years (median 5.4 years) and were not virally suppressed were tested using an LAg-Avidity enzyme immunoassay (LAg-Avidity EIA), Bio-Rad Avidity assay, and BED capture enzyme immunoassay (BED-CEIA). The performance of these three assays was evaluated using various assay cutoff values [LAg-Avidity EIA: <1.0 OD-n and <2.0 OD-n; Bio-Rad Avidity assay: <40% Avidity index (AI) and <80% AI; BED-CEIA: <0.8 OD-n]. The mean LAg-Avidity EIA result was higher for subtype A than D (4.54±0.95 vs. 3.86±1.26, p<0.001); the mean Bio-Rad Avidity assay result was higher for subtype A than D (88.9%±12.5% vs. 75.1±30.5, p<0.001); and the mean BED-CEIA result was similar for the two subtypes (2.2±1.2 OD-n for subtype A, 2.2±1....
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specificity of four laboratory approaches for cross sectional hiv incidence determination analysis of samples from adults with known nonrecent hiv infection from five african countries
AIDS Research and Human Retroviruses, 2012Co-Authors: Oliver Laeyendecker, Ron Brookmeyer, Caroline E Mullis, Deborah Donnell, Jairam R Lingappa, Connie Celum, Jared M Baeten, Mary S Campbell, M EssexAbstract:Abstract Assays to determine cross-sectional HIV incidence misclassify some individuals with nonrecent HIV infection as recently infected, overestimating HIV incidence. We analyzed factors associated with false-recent misclassification in five African countries. Samples from 2197 adults from Botswana, Kenya, South Africa, Tanzania, and Uganda who were HIV infected >12 months were tested using the (1) BED capture enzyme immunoassay (BED), (2) Avidity assay, (3) BED and Avidity assays with higher assay cutoffs (BED+Avidity screen), and (4) multiassay algorithm (MAA) that includes the BED+Avidity screen, CD4 cell count, and HIV viral load. Logistic regression identified factors associated with misclassification. False-recent misclassification rates and 95% confidence intervals were BED alone: 7.6% (6.6, 8.8); Avidity assay alone: 3.5% (2.7, 4.3); BED+Avidity screen: 2.2% (1.7, 2.9); and MAA: 1.2% (0.8, 1.8). The misclassification rate for the MAA was significantly lower than the rates for the other three met...
Jack S Remington - One of the best experts on this subject based on the ideXlab platform.
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vidas test for Avidity of toxoplasma specific immunoglobulin g for confirmatory testing of pregnant women
Journal of Clinical Microbiology, 2002Co-Authors: Jose G Montoya, Oliver Liesenfeld, Sandra Kinney, Cynthia Press, Jack S RemingtonAbstract:Because congenital toxoplasmosis is almost solely the result of maternal infection acquired during gestation, it is critical to determine whether infection during pregnancy has occurred. In the United States, definitive diagnosis of the acute infection and the time of its occurrence have been compromised by a lack of systematic screening and the fact that only a single serum sample is submitted for testing. In studies in Europe, and depending on the method used, the demonstration of high-Avidity immunoglobulin G (IgG) toxoplasma antibodies has been shown to exclude infection having occurred in the first 3 to 5 months of pregnancy. We investigated the usefulness of determining the Avidity of IgG toxoplasma antibodies with a VIDAS kit (herein referred to as the VIDAS Toxo-IgG Avidity kit, the VIDAS kit essentially rules out acute infection having occurred within the 4 prior months) in the setting of a reference serology laboratory in the United States. Sera (132 samples) from 132 women in the first 16 weeks of pregnancy were chosen because at least one test in the toxoplasma serological profile (TSP) suggested or was equivocal for a recently acquired infection. High-Avidity antibodies were demonstrated in 75% of 99 sera positive with the IgM enzyme-linked immunosorbent assay (ELISA) and 31.3% of 16 sera with acute TSP results. A significant percentage of sera with equivocal results wtih the IgM ELISA or TSP also had high-Avidity test results. Of 39 women for whom treatment with spiramycin had been suggested to attempt to prevent congenital transmission, 19 (48.7%) had high-Avidity antibodies. These findings highlight the value of the VIDAS IgG Avidity kit when used in combination with the TSP to exclude recent infection, especially when only a single serum sample is available.
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effect of testing for igg Avidity in the diagnosis of toxoplasma gondii infection in pregnant women experience in a us reference laboratory
The Journal of Infectious Diseases, 2001Co-Authors: Oliver Liesenfeld, Jose G Montoya, Sandra Kinney, Cynthia Press, Jack S RemingtonAbstract:The usefulness of testing for IgG Avidity in association with Toxoplasma gondii was evaluated in a US reference laboratory. European investigators have reported that high-Avidity IgG toxoplasma antibodies exclude acute infection in the preceding 3 months. In this US study, 125 serum samples taken from 125 pregnant women in the first trimester were chosen retrospectively, because either the IgM or differential agglutination (AC/HS) test in the Toxoplasma serologic profile suggested or was equivocal for a recently acquired infection. Of 93 (74.4%) serum samples with either positive or equivocal results in the IgM ELISA, 52 (55.9%) had high-Avidity antibodies, which suggests that the infection probably was acquired before gestation. Of 87 (69.6%) serum samples with an acute or equivocal result in the AC/HS test, 35 (40.2%) had high-Avidity antibodies. Forty women were given spiramycin, to prevent congenital transmission, and 7 (17.5%) had high-Avidity antibodies. These findings highlight the value of testing a single serum sample obtained in the first trimester of pregnancy for IgG Avidity.
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effect of testing for igg Avidity in the diagnosis of toxoplasma gondii infection in pregnant women experience in a us reference laboratory
The Journal of Infectious Diseases, 2001Co-Authors: Oliver Liesenfeld, Jose G Montoya, Sandra Kinney, Jack S Remington, Cynthia J PressAbstract:The usefulness of testing for IgG Avidity in association with Toxoplasma gondii was evaluated in a US reference laboratory. European investigators have reported that high-Avidity IgG toxoplasma antibodies exclude acute infection in the preceding 3 months. In this US study, 125 serum samples taken from 125 pregnant women in the first trimester were chosen retrospectively, because either the IgM or differential agglutination (AC/HS) test in the Toxoplasma serologic profile suggested or was equivocal for a recently acquired infection. Of 93 (74.4%) serum samples with either positive or equivocal results in the IgM ELISA, 52 (55.9%) had high-Avidity antibodies, which suggests that the infection probably was acquired before gestation. Of 87 (69.6%) serum samples with an acute or equivocal result in the AC/HS test, 35 (40.2%) had high-Avidity antibodies. Forty women were given spiramycin, to prevent congenital transmission, and 7 (17.5%) had high-Avidity antibodies. These findings highlight the value of testing a single serum sample obtained in the first trimester of pregnancy for IgG Avidity. Infection with Toxoplasma gondii during pregnancy may lead to severe sequelae in the fetus [1]. At present, definitive serologic
He S Yang - One of the best experts on this subject based on the ideXlab platform.
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top plus is a versatile biosensor platform for monitoring sars cov 2 antibody durability
Clinical Chemistry, 2021Co-Authors: Sabrina E Racinebrzostek, Mohsen Karbaschi, Christian Gaebler, Per Johan Klasse, Jim Yee, Marina Caskey, He S Yang, Ying HaoAbstract:BACKGROUND: Low initial SARS-CoV-2 antibody titers dropping to undetectable levels within months after infection have raised concerns over long term immunity. Both the antibody levels and Avidity of the antibody-antigen interaction should be examined to understand the quality of the antibody response. METHODS: A testing-on-a-probe "plus" panel (TOP-Plus) was developed, which included a newly developed Avidity assay built into the previously described SARS-CoV-2 TOP assays that measured total antibody (TAb), surrogate neutralizing antibody (SNAb), IgM and IgG on a versatile biosensor platform. TAb and SNAb levels were compared with Avidity in previously infected individuals at 1.3 and 6.2 months post-infection in paired samples from 80 COVID-19 patients. Sera from SARS-CoV-2 vaccinated individuals were also evaluated for antibody Avidity. RESULTS: The newly designed Avidity assay in this TOP panel correlated well with a reference Bio-Layer Interferometry Avidity assay (r=0.88). The imprecision of the TOP Avidity assay was less than 10%. Although TAb and neutralization activity (by SNAb) decreased between 1.3 and 6.2 months post-infection, the antibody Avidity increased significantly (P < 0.0001). Antibody Avidity in 10 SARS-CoV-2 vaccinated individuals (median 28 days post-vaccination) was comparable to the measured antibody Avidity in infected individuals (median 26 days post-infection). CONCLUSION: This highly precise and versatile TOP-Plus panel with the ability to measure SARS-CoV-2 TAb, SNAb, IgG and IgM antibody levels and Avidity of individual sera on one sensor can become a valuable asset in monitoring not only SARS-CoV-2-infected patients, but also the status of individuals' COVID-19 vaccination response.
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top plus is a versatile biosensor platform for monitoring sars cov 2 antibody durability
medRxiv, 2021Co-Authors: Sabrina E Racinebrzostek, Mohsen Karbaschi, Christian Gaebler, Per Johan Klasse, Jim Yee, Marina Caskey, He S YangAbstract:Abstract Background There is a concern that low initial SARS-CoV-2 antibody titers in individuals may drop to undetectable levels within months after infection. Although this may raise concerns over long term immunity, both the antibody levels and Avidity of the antibody-antigen interaction should be examined to understand the quality of the antibody response. Methods A testing-on-a-probe “plus” panel (TOP-Plus) was developed, which included a newly developed Avidity assay built into the previously described SARS-CoV-2 TOP assays that measured total antibody (TAb), surrogate neutralizing antibody (SNAb), IgM and IgG on a versatile biosensor platform. TAb and SNAb levels were compared with Avidity in previously infected individuals at 1.3 and 6.2 months post-infection in paired samples from 80 COVID-19 patients. Results The newly designed Avidity assay in this TOP panel correlated well with a reference Bio-Layer Interferometry Avidity assay (R=0.88). The imprecision of the TOP Avidity assay was less than 9%. Although TAb and neutralization activity (by SNAb) decreased between 1.3 and 6.2 months post infection, the antibody Avidity increased significantly (P Conclusion This highly precise and versatile TOP-Plus panel with the ability to measure SARS-CoV-2 TAb, SNAb, IgG and IgM antibody levels and Avidity of individual sera on one sensor can become a valuable asset in monitoring not only SARS-CoV-2-infected patients, but also the status of individuals’ COVID-19 vaccination response.
Sherry Passador - One of the best experts on this subject based on the ideXlab platform.
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Avidity maturation of antibody to haemophilus influenzae type b hib after immunization with diphtheria tetanus acellular pertussis hib hepatitis b combined vaccine in infants
The Journal of Infectious Diseases, 1999Co-Authors: Michael E Pichichero, Timothy Voloshen, Diane Zajac, Sherry PassadorAbstract:Antibody Avidity to Haemophilus influenzae type b (Hib) polysaccharide (PS) was assessed in infants vaccinated with diphtheria-tetanus-acellular pertussis (DTaP) combined with Hib-PS conjugated to tetanus toxoid (PRP-T) and hepatitis B (HB) (DTaP-PRP-T-HB) and after a PRP-conjugate (CRM197-OS) booster 3-7 months later. Avidity differed between infants with anti-Hib-PS IgG antibody 1 microg/mL postprimary series (Avidity index [AI], 42%, 95% confidence interval [CI], 35%-49%, and 68% and 63%-72%, respectively; P<.0001). For infants with <1 microgram/mL anti-Hib-PS IgG antibody, mean AI rose by the time of preboost immunization to 61% (95% CI, 57%-65%), even though total IgG antibody levels fell. Spontaneous Hib-PS antibody rises after primary series DTaP-PRP-T-HB vaccination were followed by high postboost anti-Hib-PS IgG antibody levels and Avidity. The DTaP-PRP-T-HB combination vaccine studied elicits high Avidity antibody, and affinity maturation appears to occur in the absence of further antigen exposure even in those with very low anti-Hib-PS antibody.
Oliver Liesenfeld - One of the best experts on this subject based on the ideXlab platform.
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vidas test for Avidity of toxoplasma specific immunoglobulin g for confirmatory testing of pregnant women
Journal of Clinical Microbiology, 2002Co-Authors: Jose G Montoya, Oliver Liesenfeld, Sandra Kinney, Cynthia Press, Jack S RemingtonAbstract:Because congenital toxoplasmosis is almost solely the result of maternal infection acquired during gestation, it is critical to determine whether infection during pregnancy has occurred. In the United States, definitive diagnosis of the acute infection and the time of its occurrence have been compromised by a lack of systematic screening and the fact that only a single serum sample is submitted for testing. In studies in Europe, and depending on the method used, the demonstration of high-Avidity immunoglobulin G (IgG) toxoplasma antibodies has been shown to exclude infection having occurred in the first 3 to 5 months of pregnancy. We investigated the usefulness of determining the Avidity of IgG toxoplasma antibodies with a VIDAS kit (herein referred to as the VIDAS Toxo-IgG Avidity kit, the VIDAS kit essentially rules out acute infection having occurred within the 4 prior months) in the setting of a reference serology laboratory in the United States. Sera (132 samples) from 132 women in the first 16 weeks of pregnancy were chosen because at least one test in the toxoplasma serological profile (TSP) suggested or was equivocal for a recently acquired infection. High-Avidity antibodies were demonstrated in 75% of 99 sera positive with the IgM enzyme-linked immunosorbent assay (ELISA) and 31.3% of 16 sera with acute TSP results. A significant percentage of sera with equivocal results wtih the IgM ELISA or TSP also had high-Avidity test results. Of 39 women for whom treatment with spiramycin had been suggested to attempt to prevent congenital transmission, 19 (48.7%) had high-Avidity antibodies. These findings highlight the value of the VIDAS IgG Avidity kit when used in combination with the TSP to exclude recent infection, especially when only a single serum sample is available.
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effect of testing for igg Avidity in the diagnosis of toxoplasma gondii infection in pregnant women experience in a us reference laboratory
The Journal of Infectious Diseases, 2001Co-Authors: Oliver Liesenfeld, Jose G Montoya, Sandra Kinney, Cynthia Press, Jack S RemingtonAbstract:The usefulness of testing for IgG Avidity in association with Toxoplasma gondii was evaluated in a US reference laboratory. European investigators have reported that high-Avidity IgG toxoplasma antibodies exclude acute infection in the preceding 3 months. In this US study, 125 serum samples taken from 125 pregnant women in the first trimester were chosen retrospectively, because either the IgM or differential agglutination (AC/HS) test in the Toxoplasma serologic profile suggested or was equivocal for a recently acquired infection. Of 93 (74.4%) serum samples with either positive or equivocal results in the IgM ELISA, 52 (55.9%) had high-Avidity antibodies, which suggests that the infection probably was acquired before gestation. Of 87 (69.6%) serum samples with an acute or equivocal result in the AC/HS test, 35 (40.2%) had high-Avidity antibodies. Forty women were given spiramycin, to prevent congenital transmission, and 7 (17.5%) had high-Avidity antibodies. These findings highlight the value of testing a single serum sample obtained in the first trimester of pregnancy for IgG Avidity.
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effect of testing for igg Avidity in the diagnosis of toxoplasma gondii infection in pregnant women experience in a us reference laboratory
The Journal of Infectious Diseases, 2001Co-Authors: Oliver Liesenfeld, Jose G Montoya, Sandra Kinney, Jack S Remington, Cynthia J PressAbstract:The usefulness of testing for IgG Avidity in association with Toxoplasma gondii was evaluated in a US reference laboratory. European investigators have reported that high-Avidity IgG toxoplasma antibodies exclude acute infection in the preceding 3 months. In this US study, 125 serum samples taken from 125 pregnant women in the first trimester were chosen retrospectively, because either the IgM or differential agglutination (AC/HS) test in the Toxoplasma serologic profile suggested or was equivocal for a recently acquired infection. Of 93 (74.4%) serum samples with either positive or equivocal results in the IgM ELISA, 52 (55.9%) had high-Avidity antibodies, which suggests that the infection probably was acquired before gestation. Of 87 (69.6%) serum samples with an acute or equivocal result in the AC/HS test, 35 (40.2%) had high-Avidity antibodies. Forty women were given spiramycin, to prevent congenital transmission, and 7 (17.5%) had high-Avidity antibodies. These findings highlight the value of testing a single serum sample obtained in the first trimester of pregnancy for IgG Avidity. Infection with Toxoplasma gondii during pregnancy may lead to severe sequelae in the fetus [1]. At present, definitive serologic
