Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPSHIMOKAWA, Paulo TadashiTARGA, Lilia SpaletaYAMAMOTO, LidiaRODRIGUES, Jonatas CristianKANUNFRE, Kelly AparecidaOKAY, Thelma Suely2016-10-172016-10-172016VIRULENCE, v.7, n.4, p.456-464, 20162150-5594https://observatorio.fm.usp.br/handle/OPI/16267Host and parasite genotypes are among the factors associated with congenital toxoplasmosis pathogenesis. As HLA class II molecules play a key role in the immune system regulation, the aim of this study was to investigate whether HLA-DQA1/B1 alleles are associated with susceptibility or protection to congenital toxoplasmosis. One hundred and twenty-two fetuses with and 103 without toxoplasmosis were studied. The two study groups were comparable according to a number of socio-demographic and genetic variables. HLA alleles were typed by PCR-SSP. In the HLA-DQA1 region, the allele frequencies showed that *01:03 and *03:02 alleles could confer susceptibility ( OR= 3.06, p = 0.0002 and OR=9.60, p= 0.0001, respectively) as they were more frequent among infected fetuses. Regarding the HLA-DQB1 region, the *05: 04 allele could confer susceptibility ( OR = 6.95, p < 0.0001). Of the 122 infected fetuses, 10 presented susceptibility haplotypes contrasting with only one in the non-infected group. This difference was not statistically significant after correction for multiple comparison ( OR = 9.37, p=0.011). In the casuistic, there were two severely damaged fetuses with high parasite loads determined in amniotic fluid samples and HLA-DQA1 susceptibility alleles. In the present study, a discriminatory potential of HLA-DQA1/B1 alleles to identify susceptibility to congenital toxoplasmosis and the most severe cases has been shown.engrestrictedAccessCongenital toxoplasmosisGenetic polymorphismGenetic susceptibilityHLA allelespolymerase chain reactionpolymerase-chain-reactionsequence-specific primersamniotic-fluid samplesgondii infectionfollow-upmaternal reinfectionmolecular diagnosisgestational-agehuman-diseasehla systemarticleCopyright TAYLOR & FRANCIS INC10.1080/21505594.2016.1150401ImmunologyInfectious DiseasesMicrobiology2150-5608