Detecção de anticorpos IgG, IgM e IgA anti-Toxoplasma gondii em amostras de soro e leite de mulheres puérperas

Abstract

Toxoplasma gondii is an obligate intracellular parasite that is able to infect many species throughout the world. It is estimated that plus one billion of people are infected worldwide. Seroprevalence of Toxoplasma gondii infection in women at childbearing age ranges from 4% to 100%. The aims of the present study were to detect IgG, IgM and IgA antibodies against Toxoplasma gondii and to compare the frequency of these antibody isotypes in serum and breast milk samples from lactating women in Uberlândia, MG, Brazil. Specimens of serum and breast milk were obtained simultaneously from each one between 15 and 30 days postpartum. Specimens were assayed by enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test (IFAT) and Western blot (WB) assay to detect IgG, IgM and IgA antibodies to T. gondii. ELISA was used as screening test, followed by IFI, and samples that presented discordant results were then assayed by WB as confirmatory test.The IgG and IgA antibodies were detected in 56,1% and 20,4%, respectively, in serum samples. The IgG and IgA combined were detected in 46,1% and 47,1% , respetively, in milk samples. No sample was reactive for IgM, lonely or with other isotype.Considering the lack of data to prove T. gondii transmission through maternal milk in humans and the fact that infected mothers can efficiently transfer antibodies from different isotypes to the child through the milk, it can be proposed that breast feeding should not be discontinued. In the present study, the IgG and IgA antibodies were detected in serum and milk samples. The IgG antibody was the most frequent isotype detected in serum samples followed by IgA in a significant lower occurrence. For milk samples, however, both IgA and IgG antibodies were detected in similar proportions.