ABSTRACT
An apparently paradoxical role for IFN-gamma in human Chagas'disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with bendnidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas'disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.
Subject(s)
Humans , Chagas Disease/immunology , Chagas Disease/physiopathology , Interferon-gamma/physiology , Chagas Disease/blood , Leukocytes, MononuclearABSTRACT
Hemoculture tests, a method for the detection of Trypanosoma cruzi, wre used to investigate the effects of the anticoagulants heparin or EDTA on the parasite growth in culture medium (liver infusion tryptose, LIT). Hemocultures from 13 patients with positive serology for chronic Chagas' disease performed in parallel with both anticoagulants resulted in a total of seven (54%) positive hemocultures, three positive with blood samples collected with EDTA (23%), two with heparin (15%) and two with both anticoagulants (15%). There was no significant difference between the number of positive tubes in blood samples collected with either heparin (11%) or with EDTA (13%), an indication that heparin does not block the growth of T. cruzi. However, the simultaneous use of both anticoagulants may improve the positivity index of the hemocultures
Subject(s)
Adult , Middle Aged , Humans , Male , Female , Blood/parasitology , Chagas Disease/parasitology , Edetic Acid/pharmacology , Heparin/pharmacology , Trypanosoma cruzi/drug effects , Culture MediaABSTRACT
Anticorpos contra estruturas vasculares do coracao e intersticio de musculatura estriada (anticorpos EVI) persistem em pacientes com doencas de Chagas curados por tratamento especifico e que apresentam negativos o xenodiagnostico, sorologia convencional (SC) e o teste de lise mediada por complemento (LMCo). Alem disso, o anticorpo EVI pode estar presente ou nao em pacientes tratados que apresentam SC positiva mas LMCo negativa. Como a LMCo detecta anticorpos associados a resistencia, os anticorpos EVI provavelmente nao participam do controle de infeccao pelo T. cruzi (embora sejam induzidos por antigenos comuns a estruturas cardiacas e ao parasita) Os anticorpos EVI nao sao tambem necessariamente relacionados aos anticorpos responsaveis pela SC. Experiencias de absorcao com T. cruzi e tecido cardiaco confirmam a sugestao de que esses anticorpos sao induzidos por varios determinantes antigenicos, a maioria dos quais de tecido cardiaco mas com menor participacao de antigenos do T. cruzi