Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/25479
Title: Establishing tools for early diagnosis of congenital toxoplasmosis: Flow cytometric IgG avidity assay as a confirmatory test for neonatal screening.
Authors: Tonini, Aline de Castro Zacche
Fonseca, Giuliana Schmidt França
Jesus, Laura Néspoli Nassar Pansini de
Barros, Geisa Baptista
Reis, Jordana Grazziela Alves Coelho dos
Béla, Samantha Ribeiro
Machado, Anderson Silva
Carneiro, Ana Carolina Aguiar Vasconcelos
Andrade, Gláucia Manzan Queiroz
Santos, Daniel Vitor Vasconcelos
Januário, José Nélio
Carvalho, Andréa Teixeira de
Vitor, Ricardo Wagner Almeida
Ferro, Eloísa Amália Vieira
Mineo, José Roberto
Martins Filho, Olindo Assis
Lemos, Elenice Moreira
UFMG Congenital Toxoplasmosis Brazilian Group
Affilliation: Universidade Federal do Espírito Santo. Vitória, ES, Brazil
Universidade Federal do Espírito Santo. Vitória, ES, Brazil
Universidade Federal do Espírito Santo. Vitória, ES, Brazil
Universidade Federal do Espírito Santo. Vitória, ES, Brazil
Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brazil
Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil/Núcleo de Ações e pesquisa em Apoio Diagnóstico. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil
Núcleo de Ações e pesquisa em Apoio Diagnóstico. Belo Horizonte, MG, Brazil
Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil
Universidade Federal de Uberlândia. Uberlândia, MG, Brazil
Universidade Federal de Uberlândia. Uberlândia, MG, Brazil
Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brazil
Universidade Federal do Espírito Santo. Vitória, ES, Brazil
Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brazil
Abstract: The aim of this study was to evaluate the performance of conventional serology (Q-Preven™ and ELFAVIDAS™) and flow cytometry-based serologic tools for early serologic diagnosis of congenital toxoplasmosis. The study groups included prospectively confirmed cases of congenital toxoplasmosis (TOXO = 88) and age-matching non-infected controls (NI = 15).The results demonstrated that all samples tested positive/indeterminate for anti-T. gondii IgM screening at birth using air-dried whole blood samples. Serum samples collected at 30–45 days after birth tested positive for ELFAVIDAS™ IgG in both groups. While all NI tested negative for ELFAVIDAS™ IgM and IgA, only 78% and 36% of TOXO tested positive for IgM and IgA, respectively. Flow cytometry-based anti-T. gondii IgM, IgA and IgG reactivity displayed moderate performance with low sensitivity (47.6%, 72.6% and 75.0%, respectively). Regardless the remarkable specificity of IgG1, IgG2 and IgG3 subclasses for early diagnosis, weak or moderate specificity was observed (Se = 73.9%, 60.2% and 83.0%, respectively). The analysis of IgG avidity indices (AI) demonstrated the highest performance among the flow cytometry-based methods (Se = 96.6%; Sp = 93.3%), underscoring the low avidity index (AI < 60%) within TOXO (97.0%) in contrast with the high avidity index (AI > 60%) in NI (93%). Analysis of anti-T. gondii IgG and IgG3 reactivity for mother:infant paired samples may represent a relevant complementary tests for early diagnosis. In conclusion, a feasible high-standard algorithm (Accuracy = 97.1%) was proposed consisting of Q-Preven™ IgM screening at birth, followed by ELFAVIDAS™ IgM and flow cytometric IgG avidity analysis at 30–45 days after birth as a high performance tool for early serological diagnosis of congenital toxoplasmosis.
Keywords: Congenital T. gondii infection
Flow cytometry
Serological diagnosis
IgM screening,
IgG avidity
keywords: infecção congenital
citometria de fluxo
diagnostico sorologico
Issue Date: 2017
Publisher: Elsevier
Citation: TONINI, Aline de Castro Zacche et al. Establishing tools for early diagnosis of congenital toxoplasmosis: Flow cytometric IgG avidity assay as a confirmatory test for neonatal screening. J Immunol Methods. , v. 451, p. 37-47, 2017.
DOI: 10.1016/j.jim.2017.08.005
ISSN: 0022-1759
Copyright: restricted access
Appears in Collections:MG - IRR - Artigos de Periódicos

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