Background: The aim of this study was to evaluate the association between clinical signs of congenital toxoplasmosis and IgG subclasses found in newborns participating in the Minas Gerais State Neonatal Screening Program.
Methods: Neonates with confirmed congenital toxoplasmosis underwent standardized ophthalmologic evaluation, neuroimaging studies and hearing assessment, as well as enzyme-linked immunosorbent assay testing for total IgG and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii.
Results: Newborns with congenital toxoplasmosis but without ocular lesions were more likely to present anti-rMIC3 total IgG when compared with those newborns with active or cicatricial retinochoroidal lesions. Detection of anti-rMIC3 IgG2 and IgG4 was associated with presence of retinochoroidal lesions and intracranial calcifications, with higher mean reactivity index values than unaffected newborns with congenital toxoplasmosis. Anti-STAg IgG3 was associated with newborns without neurologic damage.
Conclusions: Specific subclasses of IgG antibodies reacting with recombinant antigens of T. gondii may serve as biomarkers of neurologic and ocular changes in newborns with congenital toxoplasmosis.
From the *Departamento de Parasitologia, Instituto de Ciências Biológicas; and †Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Accepted for publication August 21, 2012.
Supported by grants from Secretaria do Estado de Saúde de Minas Gerais (SES-MG); Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil. The authors have no other funding or conflicts of interest to disclose.
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Address for correspondence: Ricardo Wagner de Almeida Vitor, PhD, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Av. Antonio Carlos 6627, Belo Horizonte, MG, Brazil - CEP: 31270–901, Fax: +55-31-34092970, E-mail: email@example.com.