We found a good association between the PCR diagnosis and the clinical signs of the disease, indicating that the PCR approaches used herein are suitable for early diagnosis of Chagas disease reactivation, with high potential to assist physicians in treatment decisions. For this purpose, an algorithm is proposed for surveillance based on the molecular tests.

Congenital infection of Trypanosoma cruzi allows transmission of this parasite through generations. Despite the problematic that this entails, little is known about the placenta environment genetic response produced against infection. We performed functional genomics by microarray analysis in C57Bl/6J mice comparing placentas from uninfected animals and from animals infected with two different T. cruzi strains: K98, a clone of the non-lethal myotropic CA-I strain (TcI), and VD (TcVI), isolated from a human case of congenital infection. Analysis of networks by GeneMANIA of differentially expressed genes showed that “Secretory Granule” was a pathway down-regulated in both infected groups, whereas “Innate Immune Response” and “Response to Interferon-gamma” were pathways up-regulated in VD infection but not in K98. Applying another approach, the GSEA algorithm that detects small changes in predetermined gene sets, we found that metabolic processes, transcription and macromolecular transport were down-regulated in infected placentas environment and some pathways related to cascade signaling had opposite regulation: over-represented in VD and down-regulated in K98 group. We also have found a stronger tropism to the placental organ by VD strain, by detection of parasite DNA and RNA, suggesting living parasites. Our study is the first one to describe in a murine model the genetic response of placental environment to T. cruzi infection and suggests the development of a strong immune response, parasite genotype-dependent, to the detriment of cellular metabolism, which may contribute to control infection preventing the risk of congenital transmission.

This study shows that IHC with the tested antiserum increases the sensitivity of the diagnosis and may be recommended for routine use in EMB analyses of cardiac transplant patients with Chagas disease.

Transplante cardíaco é opção terapêutica considerada no estágio avançado da cardiomiopatia chagásica. Contudo, após transplante, o diagnóstico diferencial de rejeição versus reativação chagásica tem sido considerado difícil, dificultando o tratamento correto. O motivo pelo qual alguns pacientes chagásicos apresentam reativação da doença póstransplante é desconhecido. Estima-se que há fatores relacionados à variabilidade genética do parasito. Então, investigamos a possibilidade de utilização de PCRs direcionadas para marcadores nucleares (rDNA 24Sα) e mitocondriais (kDNA) para detecção do Trypanosoma cruzi em corações de pacientes chagásicos transplantados; assim como, a ocorrência de subpopulações de T. cruzi mais associadas à reativação da infecção, utilizando um triplo ensaio para determinação de DTUs (marcadores para COII, espaçador intergênico do miniéxon, rDNA 24Sα). Foram analisadas 991 biópsias endomiocárdicas (BEMs), derivadas de 98 pacientes, 14 biópsias de pele e três de sistema nervoso central (SNC). DNA de T. cruzi foi detectado em 205 BEMs (70 pacientes), oito biópsias de pele e três de SNC. Comparada às outras técnicas de diagnóstico utilizadas, PCR revelou sensibilidade superior, com boa especificidade, podendo antecipar a reativação clínica da doença de Chagas entre 1,5 e 36 meses (média 9,1 meses), contribuindo para o diagnóstico precoce. A maioria dos pacientes teve reativação por TcII, corroborando com a ideia de que esta é a principal DTU associada com a forma cardíaca da doença de Chagas, pelo menos nesta região geográfica.