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Transplacental transmission by Trypanosoma cruzi (T. cruzi) infection can be effectively treated if parasiticide drugs are administered as early as possible during childhood. Furthermore, an ideal situation would be to diagnose the infection near birth in order to avoid the loss of patients during the subsequent follow-up. These situation are desirable due to the maximum benefit of drugs in early stages which, consequently, implies a relevant contribution to eliminate mother-to-child transmission. However, available techniques for that purpose have limitations as being operator-dependent (microhematocrit), require several months follow-up (IgG detection) or specialized laboratories (PCR). In this study we propose to detect specific IgM antibodies (Ab) by developing a capture-based ELISA employing an improved antigen (Ag) to diagnose the transplacental transmission of T. cruzi, and in consequence, to enhance access to effective treatment. Firstly, a new chimera Ag (CP4) was obtained from the fusion of CP1 and CP3 protein, carrying FRA, SAPA, MAP, TSSAII/V/VI and TcD Ag from T. cruzi. Then, we optimized the assay by capturing IgM Ab with a polyclonal anti-IgM Ab and evaluating three Ag formulations to detect specific IgM bound. The formulations were formed as follows: i) F1: CP1 and CP3; ii) F2: CP1, CP3, B13 and P2β; iii) F3: by CP4. Detection of Ab-binding Ag was carried out using an anti-His Ab since all Ag were expressed with a His-tag. The evaluation panel consisted of sera from vertically infected children under 1-year-old (6 younger than 15 days, 7 older) and samples from non-infected children of women with chronic Chagas Disease. The ELISA assay employing CP4 showed better performance with notable high sensitivity and specificity (92.3% and 93.9%, respectively). Positive and negative likelihood ratios of the test (15.2 and 0.082) suggest its potential clinical relevance in term of post-test probability of infection. In conclution, we developed a standardized and non-operator dependent test to detect specific anti-T. cruzi IgM Ab. Although increased sample size is needed for its validation, our results indicate that this capture-based technique employing CP4 Ag can certainly improve the diagnosis of connatal infection., (Copyright © 2020. Published by Elsevier B.V.)

Objective The aim of the present research was to evaluate the correlation of vertically transmitted IgG antibodies induced by T. cruzi and newborn early outcome assessment, mainly birth weight and gestational age. Methods We performed a cross-sectional study with 183 pregnant women (64 with asymptomatic Chagas disease) and their newborns. Both were subjected to complete clinical examination. Peripheral parasitemia was assessed in mother and neonates by parasite detection through microscopic examination of the buffycoat from mother's peripheral and cord blood. Antibodies induced by T. cruzi, such as anti-FRA, anti-B13, anti-p2β and anti- T. cruzi were assessed by immunoassay. Birth weight, general condition evaluation by APGAR Score and gestational age by Capurro Score, were determined in newborns. Results The rate of stillbirth background and pregnancy-induced hypertension were higher in patients with Chagas disease ( p = 0.01 and p = 0.02, respectively). Parasitemia was detectable in 17 mothers and 4 newborns. The newborns of mothers with detectable parasitemia presented decreased gestational age ( p = 0.006) and body weight ( p = 0.04). Mostly all the mothers with Chagas disease and all their newborns have positive values of antibodies induced by T. cruzi; however, only anti-p2β showed to be related to the presence of complication during pregnancy (OR 2.35, p = 0.036), and to low birth weight (OR 1.55, p = 0.02). Conclusions Low birth weight and decreased postnatal estimation of maturity were related to detectable parasitemia in the mother. Also, vertical transmission of T. cruzi-induced autoantibodies might have clinical implication in newborns given the negative association between anti-p2β values and weight. [ABSTRACT FROM AUTHOR]