Visceral leishmaniasis is a reemerging neglected tropical disease with limitations for its diagnosis, including low concentration of antibodies in the serum of asymptomatic patients and cross-reactions. In this context, this work proposes an electrochemical immunosensor for the diagnosis of visceral leishmaniasis in a more sensitive way that is capable of avoiding cross-reaction with Chagas disease (CD). Crude Leishmania infantum antigens tested in the enzyme-linked immunosorbent assay (ELISA) were methodologically standardized to best engage to the sensor. The antibodies anti-Trypanosoma cruzi and anti-Leishmania sp. Present in serum from patients with diverse types of CD or leishmaniasis were chosen. A screen-printed carbon electrode modified with gold nanoparticles was the best platform to guarantee effective adsorption of all antigens so that the epitope of specific recognition for leishmaniasis occurred efficiently and without cross-reaction with the evaluated CD. The current peaks reduced linearly after the recognition, and still were able to notice the discrimination between different kinds of diseases (digestive, cardiac, undetermined Chagas/acute and visceral chronic leishmaniasis). Comparative analyses with ELISA were performed with the same groups, and a low specificity (44%) was verified due to cross-reactions (high number of false positives) on ELISA tests, while the proposed immunosensor presented high selectivity and specificity (100%) without any false positives or false negatives for the serum samples from isolated patients with different types of CD and visceral leishmaniasis. Furthermore, the biosensor was stable for 5 days and presented a detection limit of 200 ng mL−1.

(1) Background: TNF antagonists have been used to treat autoimmune diseases (AD). However, during the chronic phase of toxoplasmosis, TNF-α and TNFR play a significant role in maintaining disease resistance and latency. Several studies have demonstrated the risk of latent infections’ reactivation in patients infected with toxoplasmosis. Our objective was to verify whether patients with autoimmune rheumatic diseases, who use TNF antagonists and/or synthetic drugs and had previous contact with Toxoplasma gondii (IgG+), present any indication of an increased risk of toxoplasmosis reactivation. (2) Methods: Blood samples were collected, and peripheral blood mononuclear cells (PBMCs) were evaluated after stimulation with antigens of Toxoplasma gondii, with anti-CD3/anti-CD28 or without stimulus, at 48 and 96 h. CD69+, CD28+, and PD-1 stains were evaluated, in addition to intracellular expression of IFN-γ, IL-17, and IL-10 by CD4+ and the presence of regulatory CD4+ T cells by labeling CD25+, FOXP3, and LAP. The cytokines IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α, and IL-17 were measured in the culture supernatant after 96 h. Serology for IgG and IgG1 was evaluated. (3) Results: There were no differences in the levels of IgG and IgG1 between the groups, but the IgG1 avidity was reduced in the immunobiological group compared to the control group. All groups exhibited a significant correlation between IgG and IgG1 positivity. CD4+ T lymphocytes expressing PD-1 were increased in individuals suffering from autoimmune rheumatic diseases and using disease-modifying antirheumatic drugs. In addition, treatment with TNF blockers did not seem to influence the populations of regulatory T cells and did not interfere with the expression of the cytokines IFN-γ, IL-17, and IL-10 by CD4+ cells or the production of cytokines by PBMCs from patients with AD. (4) Conclusions: This study presents evidence that the use of TNF-α blockers did not promote an immunological imbalance to the extent of impairing the anti-Toxoplasma gondii immune response and predisposing to toxoplasmosis reactivation.

Objetivo: Investigar a presença de IgG e IgM anti-Toxoplasma gondii no soro de estudantes de Ciências Biológicas da Universidade Federal de Uberlândia, campus do Pontal. Métodos: Estudo transversal de prevalência, com coleta de dados realizada entre junho de 2017 e fevereiro de 2018. Foram utilizadas as técnicas de Imunofluorescência Indireta e Ensaio Imunoenzimático (ELISA) e aplicados questionário semiestruturado para avaliação dos conhecimentos prévios sobre a toxoplasmose. Resultados: Participaram do estudo 128 alunos com faixa etária de 18 a 41 anos, sendo 83 (64,4%) do sexo feminino e 45 (35,6%) do sexo masculino. Foram colhidas amostras de sangue de 106 participantes e 13 (12,3%) apresentaram anticorpos anti-T. gondii.  Destes, 3 (2,8%) afirmaram consumir leite bovino não pasteurizado, 3 (2,8%) carne crua ou mal passada e 1 (0,94%) vegetais crus ou não higienizados. Não foi observada associação estatisticamente significativa entre positividade (IgM anti-T. gondii e/ou IgG anti-T. gondii) e as variáveis analisadas no questionário.Conclusão: Neste trabalho foi possível verificar a presença de anticorpos IgM e IgG anti-T. gondii em universitários. Não se observou uma associação entre soropositividade e o hábito alimentar.  Entretanto, a análise das respostas obtidas no questionário mostrou comportamento de risco por parte destes indivíduos, principalmente ao que se refere ao contato frequente com cães e gatos, muitas vezes recolhidos na rua.