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Meroni V, Genco F, Scudeller L, Brenier-Pinchart MP, Fricker-Hidalgo H, L’Ollivier C, Paris L, Pelloux H. Diagnostic Accuracy of LDBIO-Toxo II IgG and IgM Western Blot in Suspected Seroconversion in Pregnancy: A Multicentre Study. Pathogens 2022; 11:pathogens11060665. [PMID: 35745519 PMCID: PMC9231380 DOI: 10.3390/pathogens11060665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 02/01/2023] Open
Abstract
The high sensitivity of the automated tests used for Toxoplasma gondii serology can yield false-positive IgM results due to aspecific reactions. On the other hand, specific therapy can delay IgG production and, therefore, the diagnosis of seroconversion. There is a need for confirmation tests to early detect seroconversions during pregnancy. We conducted a multicentre study to evaluate the diagnostic accuracy of the Toxo II IgG and a new, not yet commercialised Toxo II IgM western blot (WB) (LDBio diagnostics Lyon France) on 229 sera corresponding to 93 patients with seroconversions and 158 sera corresponding to 68 patients with nonspecific IgM. Sensitivity was 97.8% for IgM WB and 98.9% for IgG WB. Specificity was 89.7% and 100%, respectively. The concordance between IgM and IgG Toxo WB with the final diagnosis was very good, K = 0.89 and K = 0.99, respectively. In 5 cases (5.4%), the appearance of IgM, and in 55 cases (59.1%), the appearance of IgG was recorded by WB earlier than by traditional tests. In 10 cases (10.8%), IgM was detected after the traditional tests and in 2 cases (2.2%) for IgG. The association of IgG and IgM WB on the same sample not only detected all seroconversions but also correctly identified most of the false-positive results.
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Affiliation(s)
- Valeria Meroni
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy;
| | - Francesca Genco
- Microbiology and Virology Unit, Fondazione IRCCS San Matteo Hospital Foundation, 27100 Pavia, Italy;
| | - Luigia Scudeller
- UOC Innovation and Research, IRCCS University Hospital Sant’Orsola, 40138 Bologna, Italy;
| | - Marie-Pierre Brenier-Pinchart
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
| | - Hélène Fricker-Hidalgo
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
| | - Coralie L’Ollivier
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU Méditerranée, 13005 Marseille, France;
| | - Luc Paris
- APHP-Sorbonne Université, Parasitology-Mycology, Pitié-Salpêtrière Hospital, 75013 Paris, France
- Correspondence: ; Tel.: +33-(0)1-42-16-01-60
| | - Hervé Pelloux
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
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Jean-Pierre V, Miozzo J, Fricker-Hidalgo H, Garnaud C, Robert MG, Pelloux H, Brenier-Pinchart MP. Serological diagnosis of toxoplasmosis: evaluation of the commercial test recomLine Toxoplasma IgG immunoblot (Mikrogen) based on recombinant antigens. Parasite 2022; 29:52. [PMCID: PMC9645231 DOI: 10.1051/parasite/2022050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/06/2022] [Indexed: 11/11/2022] Open
Abstract
Background: IgG detection to determine immune status to Toxoplasma gondii infection and seroconversion mainly relies on ELISA techniques and, if necessary, on a confirmatory test, Western blot. This study evaluated the performance of the recomLine Toxoplasma IgG immunoblot (IB-recomLine) (Mikrogen) as a confirmatory test on a large number of sera. A total of 171 sera were selected (113 patients) and had previously been analyzed by two ELISA tests, ARCHITECT (Abbott) and VIDAS (bioMérieux) ± LDBIO-Toxo II IgG Western blot (WB-LDBIO) (LDBio). The sera were classified into three groups: group 1 included 50 sera without difficulty in interpreting the IgG results (patients with documented past infection or uninfected); group 2 included 47 sera with difficulty in interpreting the ELISA results; and group 3 included 74 sequential sera from 25 pregnant women with seroconversion. Results: In group 1, overall IgG agreements were 94% and 90% with ARCHITECT and VIDAS, respectively. In group 2, low agreement was observed between IB-recomLine and WB-LDBIO, with eight false-positive and 13 false-negative results. In group 3, 4/13 seroconversions were detected earlier with IB-recomLine compared to other tests. Conclusions: IB-recomLine allowed for earlier diagnosis of toxoplasmic seroconversion compared to both ELISA tests and WB-LDBIO but led to insufficient performance to confirm the immune status when ELISA results were discordant or equivocal.
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Affiliation(s)
- Vincent Jean-Pierre
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
- Corresponding author:
| | - Julien Miozzo
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
| | | | - Cécile Garnaud
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
- TIMC, CNRS, Université Grenoble Alpes 38000 Grenoble France
| | - Marie Gladys Robert
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
| | - Hervé Pelloux
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
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Rym BA, Yasmine K, Hedia B, Nesrine I, Olfa S, Rania M, Karim A, Aïda B. Contribution of the Toxoplasma ICT IgG IgM ® test in determining the immune status of pregnant women against toxoplasmosis. J Clin Lab Anal 2021; 35:e23749. [PMID: 33720427 PMCID: PMC8128306 DOI: 10.1002/jcla.23749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/08/2021] [Accepted: 02/17/2021] [Indexed: 01/18/2023] Open
Abstract
Background An immunochromatography technology (ICT) rapid diagnostic test, the Toxoplasma ICT IgG‐IgM®, was recently developed. Our aim was to study its contribution to establish accurately the Toxoplasma immune status in Tunisian pregnant women using Western blot (WB) Toxo II IgG® as a reference technique. Methods Thirty‐nine sera were selected for the study from among 2,615 which were already tested by IgG and IgM ELISA. They displayed equivocal IgG titres (4.4–9 IU/ml) in absence of IgM (19 sera) or IgM anti‐Toxoplasma antibodies in absence of IgG (titre <4.4 IU/ml) (20 sera). All these sera were additionally tested by WB Toxo II IgG®. Results Immunochromatography technology Sensitivity in the detection either of low IgG titres in absence of IgM or of specific anti‐Toxoplasma IgM was 100%. Only one serum with equivocal IgG titre by ELISA and negative with Toxo II IgG® test revealed positive in ICT. However, this serum showed a P30 band in WB analysis. On the other hand, three sera positive in ELISA IgM and negative in ELISA IgG revealed positive in ICT and negative in WB Toxo II IgG®, the reference test. Conclusion Results confirm the high sensitivity of Toxoplasma ICT IgG‐IgM® in detecting both specific anti‐Toxoplasma IgG and IgM, and highlight the usefulness of this rapid test as a first or second‐line Toxoplasma serological test in pregnant women.
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Affiliation(s)
- Ben-Abdallah Rym
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia.,Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT-06, Pasteur Institute of Tunis, University Tunis El-Manar, Tunis, Tunisia
| | - Kalboussi Yasmine
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia
| | - Bellali Hedia
- Department of Epidemiology, Abderrahmane Mami Hospital, Ariana, Tunisia
| | - Issaoui Nesrine
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia
| | - Souissi Olfa
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia
| | - Maatoug Rania
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia
| | - Aoun Karim
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia.,Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT-06, Pasteur Institute of Tunis, University Tunis El-Manar, Tunis, Tunisia
| | - Bouratbine Aïda
- Department of Parasitology, Pasteur Institute of Tunis, Tunis, Tunisia.,Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT-06, Pasteur Institute of Tunis, University Tunis El-Manar, Tunis, Tunisia
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Steinberg HE, Bowman NM, Diestra A, Ferradas C, Russo P, Clark DE, Zhu D, Magni R, Malaga E, Diaz M, Pinedo-Cancino V, Ramal Asayag C, Calderón M, Carruthers VB, Liotta LA, Gilman RH, Luchini A. Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles. PLoS Negl Trop Dis 2021; 15:e0009199. [PMID: 33651824 PMCID: PMC7954332 DOI: 10.1371/journal.pntd.0009199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 03/12/2021] [Accepted: 02/02/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma in blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment. METHOLOGY/PRINCIPLE FINDINGS Here we describe proof of concept for a novel urine diagnostics for TE using Poly-N-Isopropylacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Limit of detection was 7.8pg/ml and 31.3pg/ml of T. gondii antigens GRA1 and SAG1, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1) T. gondii serology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected, T. gondii seropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry parallel-reaction-monitoring (PRM) for the presence of T. gondii antigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic. CONCLUSION/SIGNIFICANCES Our results demonstrate nanoparticle technology's potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.
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Affiliation(s)
- Hannah E. Steinberg
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Natalie M. Bowman
- Division of Infectious Disease, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Andrea Diestra
- Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cusi Ferradas
- Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Paul Russo
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Virginia, United States of America
| | - Daniel E. Clark
- Vanderbilt University Medical Center, Division of Cardiovascular Medicine, Nashville, Tennessee, United States of America
| | - Deanna Zhu
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Ruben Magni
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Virginia, United States of America
| | - Edith Malaga
- Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Monica Diaz
- Department of Neurology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Viviana Pinedo-Cancino
- Laboratorio de Investigación de Productos Naturales Antiparasitarios de la Amazonía, Facultad de Medicina Humana, Universidad Nacional de la Amazonía Peruana, Iquitos, Peru
| | - Cesar Ramal Asayag
- Universidad Nacional de la Amazonía Peruana, Iquitos, Peru
- Department of Infectious Diseases, Hospital Regional de Loreto, Iquitos, Peru
| | - Maritza Calderón
- Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Lance A. Liotta
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Virginia, United States of America
| | - Robert H. Gilman
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Alessandra Luchini
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Virginia, United States of America
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Douet T, Armengol C, Charpentier E, Chauvin P, Cassaing S, Iriart X, Berry A, Fillaux J. Performance of seven commercial automated assays for the detection of low levels of anti-Toxoplasma IgG in French immunocompromised patients. ACTA ACUST UNITED AC 2019; 26:51. [PMID: 31441775 PMCID: PMC6707100 DOI: 10.1051/parasite/2019052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/02/2019] [Indexed: 11/14/2022]
Abstract
BACKGROUND Immunocompromised patients are at high risk for the development of severe toxoplasmosis from tissue cyst reactivation, the most frequently, or from recently acquired acute infections. Knowledge of serologic status is therefore crucial. Screening for toxoplasmosis is sometimes performed while patients are already immunocompromised and have a low or even undetectable IgG titer by routine automated enzyme immunoassays. The aim of this study was to assess the sensitivity and specificity of seven reagents for the detection of low levels of IgG. Sera from 354 patients were collected and analysed. RESULTS Elecsys® offered the best analytic performances, superior to those of Architect® and Platelia®, which were superior to those of Access II® and TGS TA®. Vidas II® and Liaison II® reagents exhibited poor analytical performances in this cohort. For Elecsys®, Platelia® and Architect®, new thresholds for the grey zone and positive zone have been defined to improve the sensitivity of these reagents while maintaining excellent specificity. CONCLUSIONS Commercialized assays for toxoplasmosis screening are not suitable for IgG low-level detection in patients without adapting the supplier thresholds to avoid false negative results and risk generalized toxoplasmosis.
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Affiliation(s)
- Tiphaine Douet
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France
| | - Catherine Armengol
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France - Laboratoire d'analyse biomédicale, Centre Hospitalier Comminges Pyrénées, Avenue de Saint Plancard, 31806 Saint Gaudens, France
| | - Elena Charpentier
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France
| | - Pamela Chauvin
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France
| | - Sophie Cassaing
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France - Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, 35 Chemin des Maraîchers, 31400 Toulouse, France
| | - Xavier Iriart
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France
| | - Antoine Berry
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France
| | - Judith Fillaux
- Service de Parasitologie - Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan, 330 avenue de Grande Bretagne, 31059 Toulouse, France - Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, 35 Chemin des Maraîchers, 31400 Toulouse, France
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6
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Armengol C, Cassaing S, Roques-Malecaze C, Chauvin P, Iriart X, Berry A, Fillaux J. Time before anti-Toxoplasma IgG seroconversion detection by 7 commercial assays in French pregnant women. Diagn Microbiol Infect Dis 2016; 87:103-107. [PMID: 27884549 DOI: 10.1016/j.diagmicrobio.2016.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 11/28/2022]
Abstract
We assessed the ability to early detect a toxoplasmic seroconversion between 1 immunoblot (LDBIO II®) and 6 automated assays (TGS TA®, Architect®, Vidas II®, Liaison II®, Platelia®, and Elecsys®), comparing the time before anti-Toxoplasma gondii IgG detection during infection in pregnant women. From 2007 to 2015, 620 sera of 269 women were included. The median durations before positive IgG detection with Vidas II®, Liaison II®, Platelia®, and Elecsys® were significantly longer than Architect® with differential times from 11 to 28days (P<0.001). This time was significantly shortened by the use of LDBIO®, resulting in a saving of 13days (P<0.001). The detection of a positive rate of IgG with TGS TA® was as early as Architect® (P=0.105). The ability to early detect a toxoplasmic seroconversion is not equivalent between the assays and has to be considered when selecting the reagents to reduce the time to therapeutic intervention.
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Affiliation(s)
- Catherine Armengol
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Sophie Cassaing
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France; Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, Toulouse, 31400, France
| | | | - Pamela Chauvin
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Xavier Iriart
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Antoine Berry
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Judith Fillaux
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France; Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, Toulouse, 31400, France.
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Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis. J Clin Microbiol 2016; 54:3034-3042. [PMID: 27733631 DOI: 10.1128/jcm.01193-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/28/2016] [Indexed: 11/20/2022] Open
Abstract
Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.
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Villard O, Cimon B, L'Ollivier C, Fricker-Hidalgo H, Godineau N, Houze S, Paris L, Pelloux H, Villena I, Candolfi E. Serological diagnosis of Toxoplasma gondii infection: Recommendations from the French National Reference Center for Toxoplasmosis. Diagn Microbiol Infect Dis 2015; 84:22-33. [PMID: 26458281 DOI: 10.1016/j.diagmicrobio.2015.09.009] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 11/17/2022]
Abstract
Toxoplasmosis manifests no clinical signs in 80% of cases in immunocompetent patient, causing immunization characterized by the persistence of cysts, particularly in brain, muscles, and retina. Assessing the serological status, based on testing for serum toxoplasma IgG and IgM antibodies, is essential in cases that are increasingly at risk for the more severe disease forms, such as congenital or ocular toxoplasmosis. This disease also exposes immunosuppressed patients to reactivation, which can lead to more widespread forms and increased mortality. By interpreting the serological results, we can estimate the risk of contamination or reactivation and define appropriate prophylactic and preventive measures, such as hygienic and dietetic, therapeutic, biological, and clinical follow-up, according to the clinical context. We hereby propose practical approaches based on serological data, resulting from a consensus of a group of experts from the French National Reference Center Network for Toxoplasmosis, according to both routine and specific clinical situations.
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Affiliation(s)
- O Villard
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg, Université de Strasbourg, Hôpitaux Universitaires de Strasbourg, 1-3 rue Koeberlé, F-67000 Strasbourg, France.
| | - B Cimon
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, 4 rue Larrey, F-49933 Angers Cedex 9, France
| | - C L'Ollivier
- Laboratoire de Parasitologie-Mycologie, Hôpital de la Timone, 264 rue Saint Pierre, F-13385 Marseille Cedex 05, France
| | - H Fricker-Hidalgo
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire A. Michallon et Université de Grenoble BP 217, 38043 Grenoble Cedex, France
| | - N Godineau
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier de Saint-Denis, 2 rue du Docteur Pierre Delafontaine, BP 279, F-93205 Saint-Denis Cedex, France
| | - S Houze
- Laboratoire de Parasitologie Mycologie, AP-HP Hôpital BICHAT-Claude Bernard, 46 rue Henri Huchard, F-75877 Paris Cedex 18, France
| | - L Paris
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Laboratoire de Parasitologie-Mycologie, 47-83 Boulevard de l'Hôpital, F-75651 Paris Cedex 13, France
| | - H Pelloux
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire A. Michallon et Université de Grenoble BP 217, 38043 Grenoble Cedex, France
| | - I Villena
- Laboratoire de Parasitologie-Mycologie, Hôpital Maison Blanche, Centre Hospitalier Universitaire et Université de Reims Champagne Ardennes, 45 rue Cognacq-Jay, F-51092 Reims Cedex, France
| | - E Candolfi
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg, Université de Strasbourg, Hôpitaux Universitaires de Strasbourg, 1-3 rue Koeberlé, F-67000 Strasbourg, France.
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Mouri O, Kendjo E, Touafek F, Fekkar A, Konte O, Imbert S, Courtin R, Mazier D, Paris L. The impact of lowering the cut-off value on the sensitivity of the Platelia Elisa IgG (Bio-Rad) test for toxoplasmosis diagnosis. ACTA ACUST UNITED AC 2015; 22:22. [PMID: 26187780 PMCID: PMC4506486 DOI: 10.1051/parasite/2015022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/29/2015] [Indexed: 11/17/2022]
Abstract
Determining specific immune status against Toxoplasma gondii is essential for assessing the risk of reactivation in immunocompromised patients or defining serological monitoring and appropriate prophylactic measures during pregnancy. In France, toxoplasmosis serological screening requires systematic testing for IgM and IgG antibodies. The Platelia Toxo IgG and IgM test (Bio-Rad) is one of the most widely used tests for anti-toxoplasmic antibody detection. We performed a study on 384 sera, including 123 IgG negative (<6 IU/mL) and 261 IgG equivocal (6–9 IU/mL) sera tested with Platelia Toxo IgG and collected during routine screening at Pitié-Salpêtrière Hospital, Paris, France to determine the best-performing IgG titer cut-off value. Out of these 383 sera, 298 were IgM negative by Platelia Toxo IgM and 86 were IgM positive. All sera were also tested against Toxo IgG II LD BIO western blot test as confirmation. Our results indicated that an IgG titer cut-off value of ≥4.4 IU/mL for the Platelia Toxo IgG met the definition of positivity, a value significantly lower than that indicated by the manufacturers. In the presence of IgM antibodies, the IgG titer cut-off decreased significantly to a value ≥0.2 IU/mL. This latter cut-off also allowed adequate diagnosis of proven toxoplasmosis seroconversion in 76.7% of cases (33/43). Our findings may improve toxoplasmosis care by reducing therapeutic intervention time and eliminating the need for further serological monitoring.
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Affiliation(s)
- Oussama Mouri
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Eric Kendjo
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Feriel Touafek
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Arnaud Fekkar
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France - Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, 75013 Paris, France - Sorbonne Universités, UPMC Université Paris 6, CIMI-Paris, 75005 Paris, France
| | - Ousmane Konte
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Sebastien Imbert
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Régis Courtin
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Dominique Mazier
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France - Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, 75013 Paris, France - Sorbonne Universités, UPMC Université Paris 6, CIMI-Paris, 75005 Paris, France
| | - Luc Paris
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
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10
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Meylan P, Paris L, Liesenfeld O. Multicenter evaluation of the Elecsys Toxo IgG and IgM tests for the diagnosis of infection with Toxoplasma gondii. Eur J Microbiol Immunol (Bp) 2015; 5:150-8. [PMID: 26185683 PMCID: PMC4500066 DOI: 10.1556/1886.2015.00016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 05/19/2015] [Indexed: 11/19/2022] Open
Abstract
Detection of IgG and IgM antibodies is commonly performed for the diagnosis of infection with Toxoplasma gondii. We determined the accuracy of the Elecsys Toxo IgG and IgM test at four European laboratories compared to local reference methods. Coefficients of variation for reproducibility ranged from 1.0 to 6.5% for IgG and from 0.8 to 3.2% for IgM. Seroconversion panels revealed high overall concordance with the reference tests. The Elecsys test detected IgG antibodies earlier than the Cobas Core IgG test in 19 of 47 panels; persisting IgM antibodies were observed in the VIDAS but not the Elecsys test in five of 47 panels. In 31.4% of latent stage sera with persistent IgM antibodies (positive LIASON IgM), the Elecsys IgM test gave negative results indicating increased "clinical" specificity. Sensitivity and specificity of the Elecsys IgG assay ranged from 99.45 to 100% and 87.50-99.80%, respectively, and 91.11-95.74 and 98.45-99.79% for the Elecsys IgM assay, respectively. In conclusion, excellent reproducibility and accuracy make the Elecsys Toxo G and M tests highly suitable for the detection of anti-T. gondii IgG and IgM antibodies. The lower detection rates for persistent IgM in the Elecsys IgM test increase "clinical" specificity and decrease the need for follow-up testing.
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Affiliation(s)
- Pascal Meylan
- Institute of Microbiology, Centre Hospitalier Universitaire Vaudois , Lausanne, Switzerland
| | - Luc Paris
- AP-HP, Laboratoire de Parasitologie-Mycologie, Hôpitaux Universitaires Pitié-Salpétrière - Charles Foix , Paris, France
| | - Oliver Liesenfeld
- Institute for Microbiology and Hygiene, Charité Medical School , Berlin, Germany
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11
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Khammari I, Saghrouni F, Lakhal S, Bougmiza I, Bouratbine A, Ben Said M, Boukadida J. Identification of soluble and membrane antigenic markers of acquired toxoplasmosis by immunoblot. Parasite Immunol 2014; 36:684-93. [PMID: 25384440 DOI: 10.1111/pim.12139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/13/2014] [Indexed: 11/29/2022]
Abstract
The overall performance of quantitative assays in the detection of anti-Toxoplasma IgG is satisfactory, but discrepancies between assays are not uncommon especially when IgG concentrations are close to the limit of detection of the tests. The purpose of our study was to identify soluble and membrane antigens extracted from Toxoplasma gondii tachyzoites by immunoblot to select the most relevant antigenic bands to be used for qualitative serodiagnosis of acquired toxoplasmosis. We selected five relevant bands (98, 36, 33, 32 and 21 kDa) with soluble antigens and four relevant bands (42, 35, 32 and 30 kDa) with membrane antigens which gave high sensitivity and/or specificity in immunodiagnosis. The association on the same blot of at least three of the five relevant bands in the soluble antigen immunoblot showed the highest sensitivity/specificity (97.4%/99.0%, respectively). Our results indicate that immunoblot using soluble tachyzoite extract with simultaneous detection of at least three of the five bands (98, 36, 33, 32 and 21 kDa) represents a valuable test for serodiagnosis of acquired toxoplasmosis and should be further evaluated as a confirmatory test for sera which give discrepant results in quantitative assays.
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Affiliation(s)
- I Khammari
- Research Unit (UR12SP34), Farhat Hached University Hospital, Sousse, Tunisia
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12
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Khammari I, Saghrouni F, Lakhal S, Bouratbine A, Ben Said M, Boukadida J. A new IgG immunoblot kit for diagnosis of toxoplasmosis in pregnant women. THE KOREAN JOURNAL OF PARASITOLOGY 2014; 52:493-9. [PMID: 25352697 PMCID: PMC4210731 DOI: 10.3347/kjp.2014.52.5.493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/12/2014] [Accepted: 06/15/2014] [Indexed: 11/23/2022]
Abstract
The determination of the accurate immune status of pregnant women is crucial in order to prevent congenital toxoplasmosis. Equivocal results with conventional serological techniques are not uncommon when IgG titers are close to the cut-off value of the test, so that a confirmatory technique is needed. For this purpose, we developed a homemade immunoblot (IB) using soluble extract of Toxoplasma gondii tachyzoites and assessed it by testing 154 positive, 100 negative, and 123 equivocal sera obtained from pregnant women. In order to select the more valuable bands in terms of sensitivity and specificity, we used the Youden Index (YI). The highest YIs were those given by the 32, 36, 98, 21, and 33 bands. The simultaneous presence on the same blot of at least 3 bands showed a much higher YI (0.964) and was adapted as the positivity criterion. The analysis of results showed that our homemade IB correlated well with the commercial LDBIO Toxo II IgG® kit recently recommended as a confirmatory test (96.7% of concordance).
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Affiliation(s)
- Imen Khammari
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Fatma Saghrouni
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Sami Lakhal
- Research Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR 11 IPT06 Pasteur Institute of Tunis, 13 Place Pasteur, B.P. 74, 1002 Tunis, Belvédère, Tunisia
| | - Aida Bouratbine
- Research Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR 11 IPT06 Pasteur Institute of Tunis, 13 Place Pasteur, B.P. 74, 1002 Tunis, Belvédère, Tunisia
| | - Moncef Ben Said
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Jalel Boukadida
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
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13
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A new multi-host species indirect ELISA using protein A/G conjugate for detection of anti-Toxoplasma gondii IgG antibodies with comparison to ELISA-IgG, agglutination assay and Western blot. Vet Parasitol 2014; 200:66-73. [DOI: 10.1016/j.vetpar.2013.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 11/19/2022]
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14
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Murat JB, Fricker Hidalgo H, Brenier-Pinchart MP, Pelloux H. Human toxoplasmosis: which biological diagnostic tests are best suited to which clinical situations? Expert Rev Anti Infect Ther 2014; 11:943-56. [DOI: 10.1586/14787210.2013.825441] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Khammari I, Saghrouni F, Yaacoub A, Gaied Meksi S, Ach H, Garma L, Fathallah A, Ben Saïd M. IgG western blot for confirmatory diagnosis of equivocal cases of toxoplasmosis by EIA-IgG and fluorescent antibody test. THE KOREAN JOURNAL OF PARASITOLOGY 2013; 51:485-8. [PMID: 24039295 PMCID: PMC3770883 DOI: 10.3347/kjp.2013.51.4.485] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/19/2013] [Accepted: 07/05/2013] [Indexed: 11/23/2022]
Abstract
The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.
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Affiliation(s)
- Imen Khammari
- UR 12 SP 34 Research Unit, Ministry of Public Health, Tunis, Tunisia
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16
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Souza GFD, Carvalho D, Pedrosa W, Franck J, Piarroux R. Analytical validation of anti-toxoplasma IgG immunoassays. Braz J Infect Dis 2012; 16:574-6. [DOI: 10.1016/j.bjid.2012.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/11/2012] [Indexed: 11/24/2022] Open
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17
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Utility of immunoblotting for early diagnosis of toxoplasmosis seroconversion in pregnant women. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:1908-12. [PMID: 21880851 DOI: 10.1128/cvi.05303-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Congenital transmission of Toxoplasma gondii occurs mainly when a mother acquires the infection for the first time during pregnancy. It was recently shown that although early treatment of the primary infection during pregnancy has little or no impact on the fetomaternal transmission rate, it does reduce the incidence of sequelae in infected infants. Seroconversion is defined by the appearance of IgG. Commercial reagents continue to vary considerably in detecting low concentrations of antibodies, as during early seroconversion. We compared two routinely used immunoassays (IA) (Platelia and Elecsys Toxo IgG) and an indirect immunofluorescence assay (IIF) with a qualitative test based on immunoblot analysis (Toxo II IgG) (IB) to assess their abilities to diagnose seroconversion at its earliest stages. This prospective study was carried out between January and November 2010. It included 39 pregnant women with monthly follow-up who seroconverted during pregnancy. On first sera that were IgM positive but IgG negative (or equivocal) as detected by IA, IB diagnosed seroconversion twice as often as IIF (26/39 [66.7%] versus 13/39 [33.3%]; P < 0.001; χ(2) test). Serum samples were retaken 2 to 5 weeks later for the other 13 cases (IgG negative by IB on first serum). Seroconversion was demonstrated as follows: IB for 5 cases where IA remained negative or equivocal, IB and IIF for 5 cases where IA remained negative or equivocal, IA for 2 cases, and no method for 1 case (a third sample was necessary). In summary, IB permitted toxoplasmosis seroconversion diagnosis before other means in 92.3% of cases (36/39) and thus earlier therapeutic intervention.
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18
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Zahid M, Loyau S, Bouabdelli M, Aubrey N, Jandrot-Perrus M, Billiald P. Design and reshaping of an scFv directed against human platelet glycoprotein VI with diagnostic potential. Anal Biochem 2011; 417:274-82. [PMID: 21771576 DOI: 10.1016/j.ab.2011.06.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/21/2011] [Accepted: 06/24/2011] [Indexed: 10/18/2022]
Abstract
Blood platelets play a key role in physiological hemostasis and in thrombosis. As a consequence, platelet functional analysis is widely used in the diagnosis of hemorrhagic disorders as well as in the evaluation of thrombosis risks and of the efficacy of antithrombotics. Glycoprotein (GP) VI is a platelet-specific collagen-signaling receptor. Clinical studies suggest that increased GPVI expression is associated with a risk of arterial thrombosis. Conversely, GPVI deficiencies have been identified in patients with defective platelet responses to collagen. Currently, there is no standard test available for measuring GPVI expression, essentially because antibodies usually cross-link GPVI upon binding, leading to platelet activation and consecutive changes in GPVI expression. Here, we designed a recombinant monovalent antibody fragment (scFv) derived from an anti-GPVI monoclonal IgG, 3J24, with the characteristics required to analyze GPVI expression. Guided by in silico modeling and V-KAPPA chain analysis, a Protein L (PpL) recognition pattern was engineered in the scFv, making possible its purification and detection using PpL conjugates. The PpL affinity-purified scFv is functional. It retains GPVI-binding specificity and allows detection of platelet surface-expressed GPVI without inducing platelet activation. In conclusion, the reshaped scFv may be very useful in the development of diagnostic approaches.
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Affiliation(s)
- Muhammad Zahid
- Université Paris-Sud 11, IFR 141, Faculté de Pharmacie, 92260 Châtenay-Malabry, France
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