Novas abordagens terapêuticas na Doença de Chagas: terapia celular, anticorpos, aférese / New therapheutic approaches in Chagas Disease stem cell antibodies apheresis

A doença de Chagas é considerada, atualmente, pela Organização Mundial da Saúde uma das doenças tropicais negligenciadas, com estimativa de mais de 8 milhões de pessoas infectadas em todo o mundo. Recentemente tem havido crescente interesse na doença de Chagas, importante etiologia de miocardiopatia na América Latina, devido, em grande parte, ao aumento da incidência dessa doença em países desenvolvidos. A despeito do amplo emprego de drogas antiparasitárias na forma aguda da doença de Chagas, o tratamento etiológico da miocardiopatia chagásica crônica permanece incerto, sendo o benefício para o prognóstico dos pacientes ainda indeterminado. No presente artigo realizamos revisão sistemática a respeito do emprego de terapia celular, anticorpos, vacinas e plasmaferese em pacientes com doença de Chagas. Os dados levantados indicam que, a despeito de a terapia baseada em células-tronco mostrar potencial benéfico em modelos experimentais, em seres humanos, a evidência até o momento disponível não nos autoriza a utilizar tal modalidade na rotina assistencial. Vacinas baseadas em antígenos genéticos têm potencial a ser explorado, mas sem aplicabilidade momentânea em seres humanos. Novos estudos são necessários para elucidar o uso real dessas modalidades alternativas no contexto da miocardiopatia chagásica.

ABSTRACT The World Health Organization, with an estimate of over 8 million people infected worldwide, currently considers the Chagas disease as one of the neglected tropical diseases. Recently there has been increasing interest in Chagas disease, an important etiology of cardiomyopathy in Latin America, due in large part to the increased incidence in developed countries. Despite the widespread use of antiparasitic drugs in the acute infected form of Chagas disease, etiological treatment of chronic Chagas cardiomyopathy remains uncertain, and the benefit for the prognosis of patients still undetermined. In the present article, we present a systematic review on the use of cell therapy, antibodies, vaccines and plasmapheresis in patients with Chagas disease. The data collected indicate that, despite the stem cell-based therapy showing beneficial potential in experimental models, in humans, the evidence so far available does not allows us to use this modality as a routine treatment. Vaccines based on genetic antigens have potential to be explored, but without immediate applicability in humans. Further studies are needed to elucidate the actual use of these alternative methods in the context of Chagas cardiomyopathy.

Epstein-Barr virus nuclear antigen-2 detection and typing in immunocompromised children correlated with lymphoproliferative disorder biopsy findings.

Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis, plays a significant role as a cofactor in the process of tumorigenesis, and has consistently been associated with a variety of malignancies especially in immunocompromised patients. Forty-four children and adolescents (21 liver transplant patients, 7 heart transplant, 5 AIDS, 3 autoimmune hepatitis, 2 nephritic syndromes, 2 medullar aplasia, 2 primary immunodeficiency disorder patients, 1 thrombocytopenic purpura and 1 systemic lupus erythematosus) presenting with chronic active EBV infection (VCA-IgM persistently positive; VCA-IgG > 20 AU/mL and positive IgG _ EBNA) had peripheral blood samples obtained during clinically characterized EBV reactivation episodes. DNA samples were amplified in order to detect and type EBV on the basis of the EBNA-2 sequence (EBNA2 protein is essential for EBV-driven immortalization of B lymphocytes). Although we have found a predominance of type 1 EBNA-2 virus (33/44; 75%), 10 patients (22.73%) carried type 2 EBNA-2, and one liver transplant patient (2.27%) a mixture of the two types, the higher proportion of type 2 EBV, as well as the finding of one patient bearing the two types is in agreement with other reports held on lymphoproliferative disorder (LPD) patients, which analyzed tumor biopsies. We conclude that EBNA-2 detection and typing can be performed in peripheral blood samples, and the high prevalence of type 2 in our casuistic indicates that this population is actually at risk of developing LPD, and should be monitored.

Epstein-Barr virus nuclear antigen-2 detection and typing in immunocompromised children correlated with lymphoproliferative disorder biopsy findings

Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis, plays a significant role as a cofactor in the process of tumorigenesis, and has consistently been associated with a variety of malignancies especially in immunocompromised patients. Forty-four children and adolescents (21 liver transplant patients, 7 heart transplant, 5 AIDS, 3 autoimmune hepatitis, 2 nephritic syndromes, 2 medullar aplasia, 2 primary immunodeficiency disorder patients, 1 thrombocytopenic purpura and 1 systemic lupus erythematosus) presenting with chronic active EBV infection (VCA-IgM persistently positive; VCA-IgG > 20 AU/mL and positive IgG _ EBNA) had peripheral blood samples obtained during clinically characterized EBV reactivation episodes. DNA samples were amplified in order to detect and type EBV on the basis of the EBNA-2 sequence (EBNA2 protein is essential for EBV-driven immortalization of B lymphocytes). Although we have found a predominance of type 1 EBNA-2 virus (33/44; 75 percent), 10 patients (22.73 percent) carried type 2 EBNA-2, and one liver transplant patient (2.27 percent) a mixture of the two types, the higher proportion of type 2 EBV, as well as the finding of one patient bearing the two types is in agreement with other reports held on lymphoproliferative disorder (LPD) patients, which analyzed tumor biopsies. We conclude that EBNA-2 detection and typing can be performed in peripheral blood samples, and the high prevalence of type 2 in our casuistic indicates that this population is actually at risk of developing LPD, and should be monitored.