Importância do teste de avidez IgG no diagnóstico da toxoplasmose congênita

• Autor(a) principal: Fonseca, Zulmirene Cardoso
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000007wvn
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9879
• topic: Toxoplasmose congênita; Afinidade de anticorpos; Imunoglobulina G; Recém nascido; Congenital toxoplasmosis; Antibody affinity; Immunoglobulin G; Newborn; CIENCIAS DA SAUDE

Toxoplasmosis is a infectious disease worldwide occurrence of that has as etiologic agent the protozoan Toxoplasma gondii. The main clinical manifestation of toxoplasmosis is consolidated through vertical transmission. Despite major advances in the diagnosis and treatment of congenital toxoplasmosis (CT), the search for diagnostic tests to determine when the infection was acquired and the corresponding gestation stage still represents a clinical challenge to be overcome. The IgG avidity test evaluates the binding strength of IgG antibodies against T.gondii antigen, separating the low avidity antibodies produced in the initial stage of infection of high avidity antibody, indicative of chronic infection but is not yet elucidated the value of this test in the diagnosis of CT in newborn (NB). In this context, this study aims to evaluate the predictive value of IgG avidity test in the diagnosis of CT RB. Case-control study nested in follow-up cohort of children suspected of having been born with congenital toxoplasmosis (CT), from two Maternity reference public in the city of Goiânia, Goias (Brazil). The sample consisted of 88 mothers infected by Toxoplasma gondii (T.gondii) and their newborn (RB); being 48 acutely infected during pregnancy (AIP) and 40 chronically infected (CIP) and their newborn. We evaluated serum levels of specific IgM and IgG against T.gondii IgG avidity test, by Chemiluminescence. The data generated were computerized in the Excel program 2012. The statistic was made using GraphPadPrism software version 5.04 and SPSS-Statistical Package for the Social Sciences Version 21.0. The differences were considered statistically significant when the value of p < 0.05. This allowed classifying the RB in infected (with high avidity or low avidity) and non-infected (with high avidity). The RN of the AIP were divided in RB with low avidity (LA) and RN with high avidity (HA). The TC was checked on 66.66% (n = 32) of RB of the AIP, and 94.1% of RN with LA and 42.3% of RN with HA, were infected. Levels of IgG and IgM of RN with LA and its mothers were high and showed difference when compared with the RN with HA (p = 0.0001). The symptomatology of the CT was observed in 56.2% (n=9) of RN with LA and 31.3% (n=5) of RN with HA. NB with BA exposed to T.gondii have 15 times more likely to develop the TC that NB with AA. The avidity test had a specificity of 93.78% and 50.00% sensitivity. In this context, the avidity test could be used to aid detection of CT in RB.