Early diagnosis of congenital toxoplasmosis in newborn infants using IgG subclasses against two Toxoplasma gondii recombinant proteins

Memórias do Instituto Oswaldo Cruz

Carlos Henryque De Souza E Silva¹  Gláucia Queiroz De Andrade²  José Nélio Januário²  Ana Carolina De Aguiar Vasconcelos Carneiro¹  Mariangela Carneiro¹  Daniel Vitor Vasconcelos-santos²  Ricardo Wagner De Almeida Vitor¹ 

[1] ,Universidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de ParasitologiaBelo Horizonte MG ,Brasil

关键词: congenital toxoplasmosis;    ELISA;    recombinant proteins;    IgG subclasses;   

DOI  :  10.1590/S0074-02762012000300008

来源: SciELO

【 摘 要 】

The aim of this work was to evaluate the utility of ELISA-based testing of total IgG (IgGt) antibodies and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii for diagnosing congenital toxoplasmosis. Sera from 217 newborns initially testing positive for specific IgM in filter paper dried blood spots were tested for specific IgM and IgG by ELFA-VIDAS®. Congenital toxoplasmosis was confirmed in 175 and ruled out in 42 infants. The validity of the ELISA tests was determined using the persistence of IgG antibodies (ELFA-VIDAS® kit) at the end of 12 months, which is considered the reference test for the diagnosis of congenital toxoplasmosis. The frequency of positivity with IgGt against STAg, rSAG1 and rMIC3 was found in 97.2%, 96.3% and 80.2%, respectively, of the newborns with confirmed congenital toxoplasmosis. IgG1 reacted with all three antigens, while IgG3 and IgG4 reacted preferentially with rMIC3. Higher mean values of reactivity (sample optical density/cut-off) were found for all subclasses when using rMIC3. All of the antigens showed high sensitivity and low specificity in detecting anti-T. gondii IgGt and IgG1 and low sensitivity and high specificity in detecting IgG3 and IgG4. In conclusion, the combined detection of IgG antibody subclasses against recombinant toxoplasmic antigens may be useful for the early diagnosis of congenital toxoplasmosis.

【 授权许可】

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