Humoral Immune Response against P2β from Trypanosoma cruzi in Persons with Chronic Chagas Disease: Its Relationship with Treatment Against Parasites and Myocardial Damage

We investigated the relationship between potentially pathogenic antibodies against a Trypanosoma cruzi ribosomal protein (P2β) and the evolution of Chagas disease and the effect of trypanocidal treatment on these variables. Seventy-eight patients with chronic Chagas disease who were followed-up for more than 20 years were divided into three groups: 30 asymptomatic persons undergoing specific treatment (group A), 37 asymptomatic persons not undergoing specific treatment (group B), and 11 patients with chronic chagasic cardiomyopathy (CCC) who were not treated. Five patients in group B showed evolution to myocardial abnormalities. Among persons with CCC, six showed no changes; the remaining persons showed progression of cardiac involvement. Levels of antibodies to P2β in persons in group A decreased from their initial values. This finding was not observed in persons in groups B and C. Comparisons at the end of the follow-up showed lower amounts of antibodies to P2β in groups A and C. These findings support the benefits of specific treatment during chronic infection

Evolutive behavior towards cardiomyopathy of treated (nifurtimox or benznidazole) and untreated chronic chagasic patients Evolução à miocardiopatia dos infectados chagásicos crônicos tratados (nifurtimox ou benzonidazol) e não tratados

The aim of this work was to compare the evolution of chronic chagasic untreated patients (UTPs) with that of benznidazole or nifurtimox-treated patients (TPs). A longitudinal study from a low endemic area (Santa Fe city, Argentina) was performed during an average period of 14 years. Serological and parasitological analyses with clinical exams, ECG and X-chest ray were carried out. At the onset, 19/198 infected patients showed chagasic cardiomyopathy (CrChM) while 179 were asymptomatic. In this latter group the frequency of CrChM during the follow-up was lower in TPs compared with UTPs (3.2% vs 7%). Within the CrChM group, 2/5 TPs showed aggravated myopathy whereas this happened in 9/14 UTPs. Comparing the clinical evolution of all patients, 5.9% of TPs and 13% of UTPs had unfavourable evolution, but the difference is not statistically relevant. Serological titers were assessed by IIF. Titers equal to or lower than 1/64 were obtained in 86% of the TPs, but only in 38% of UTPs. The differences were statistically significant (geometric mean: 49.36 vs. 98.2). Antiparasitic assessment of the drugs (xenodiagnosis) proved to be effective. The low sensitivity in chronic chagasic patients must be born in mind. Despite treated patients showed a better clinical evolution and lower antibody levels than untreated ones, it is necessary to carry on doing research in order to improve therapeutic guidelines, according to the risk/benefit equation and based on scientific and ethical principles.<br>Para comparar a evolução dos infectados chagásicos crônicos não tratados (UTPs) e tratados (TPs) com nifurtimox ou benznidazol, fez-se um estudo longitudinal numa área de baixa endemicidade (cidade de Santa Fe, Argentina), com média de seguimento de 14 anos. Em cada controle foram feitas análises sorológicas e parasitológicas, exames clínicos, eletrocardiográficos e radiológicos. No inicio, 19/198 infectados apresentaram miocardiopatia chagásica crônica (MChCr), enquanto 179 eram assintomáticos. A frequência de MChCr no seguimento destes últimos foi 3,2% para os tratados e 7% para os não tratados. Dos pacientes com MChCr no início, 2/5 dos tratados e 9/14 dos não tratados agravaram sua miocardiopatia. Comparando a evolução clínica dos infectados, 5,9% dos tratados e 13% dos não tratados tiveram evolução desfavorável, mas esta diferença não é estatisticamente significativa. Na avaliação sorológica por IFI, 86% dos TPs e só 38% dos UTPs apresentaram títulos menores ou iguais a 1/64. As diferenças são estatisticamente significativas (média geométrica: 49,36 vs 98,2). Os xenodiagnósticos seriados realizados, demonstraram efetividade das drogas (considerar a baixa sensibilidade deste método na etapa crônica). Os pacientes tratados mostraram melhor evolução clínica e mais baixos níveis de anticorpos do que os não tratados. É preciso continuar as investigações para estabelecer pautas terapêuticas mais claras sobre a relação risco-benefício, sustentadas nos princípios científicos e éticos