Strategy to assess the overall cytokine profile of circulating leukocytes and its association with distinct clinical forms of human Chagas disease.

Herein we have employed an alternative strategy to assess the cytokine patterns of circulating leukocytes and correlate dominant cytokine profiles with indeterminate-IND and cardiac-CARD clinical forms of Chagas disease. We have first calculated median percentages of cytokine-positive leukocytes of our study sample to establish, for each cytokine-positive cell population, the cut-off edge that would segregate 'low' and 'high' cytokine producers to build colour diagrams and draw a panoramic cytokine chart. Using this approach we demonstrated that most IND individuals presented a dominant regulatory cytokine profile, whereas CARD individuals displayed a dominant inflammatory cytokine pattern. In addition, radar chart analysis confirmed the dichotomic cytokine balance between IND and CARD groups and further allowed the identification of the relative contribution of each cell population for the global cytokine pattern. Data analysis demonstrated that CD4+ T cells were the major cell population defining the regulatory profile in IND, whereas monocytes and CD4+ T cells determined the inflammatory cytokine pattern in CARD individuals. Interestingly, in vitro stimulation with trypomastigote Trypanosoma cruzi antigen was able to invert the cytokine balances in IND and CARD groups. Upon antigenic stimulation, changes in the frequencies of IL-10-producing CD4+ T cells and monocytes drove IND individuals towards an inflammatory pattern and CARD towards a regulatory cytokine profile. A similar inversion could be found after in vivo treatment of IND and CARD individuals with benzonidazole. Altogether, these findings shed some light into the complex cytokine network underlying the immunopathogenesis of Chagas disease and provide putative immunological biomarkers of disease severity and therapeutic response.

Random amplified polymorphic DNA profiles of Trypanosoma cruzi isolates from chagasic patients with different clinical forms.

The genetic variability of 61 Trypanosoma cruzi isolates from 47 chronic chagasic patients of Minas Gerais state was analyzed by random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) using M13-40, lambdagt11-F, and L15996 primers. Cluster analysis by unweighted pair group method analysis was applied to RAPD profiles, and cluster analysis used to verify a possible correlation among different clinical forms of the disease from these patients. The T. cruzi isolates showed distinct grouping on tree topology, with the isolates not being possible to establish a correlation to the clinical forms of Chagas' disease. These data showed that the T. cruzi isolates from these patients would compose a group of populations well correlated genetically.

Analysis of anti-Trypanosoma cruzi antibody isotype specificities by western blot in sera from patients with different forms of Chagas' disease.

Infection of humans with Trypanosoma cruzi leads to either a lifelong asymptomatic infection or to symptomatic presentations such as cardiomyopathy, mega-syndromes, or both. The reasons for the different clinical manifestations are not understood. We have previously studied a group of chronically infected individuals with different clinical forms of Chagas' disease and found that the levels of some anti-T. cruzi antibody isotypes, analyzed by enzyme-linked immunosorbent assay, differed among patients with different clinical presentations. We have expanded these studies to examine the antigen specificity of these patients' IgG1, 2, 3, IgM, and IgA by western blot. We observed that binding of particular antigens by some antibody isotypes were more prevalent in some clinical groups as compared to others. For example, IgG3 from 13 of 19 (68%) individuals with digestive manifestations bound a 68-kDa antigen, but only 3 of 31 (9%) individuals with cardiac involvement detected this same moiety. We also found that, regardless of the clinical group, the profiles of antigens recognized by each antibody isotype differs dramatically from the profiles recognized by each other isotype. Together with our previous observations demonstrating that the levels of anti-parasite antibody isotypes correlates with the clinical form, these data suggest that overall anti-T. cruzi antibody reactivities may indeed be skewed toward different antigens in individuals with different clinical presentations.

Anti-Trypanosoma cruzi antibody isotype profiles in patients with different clinical manifestations of Chagas' disease.

Chagas' disease results from infection with the protozoan hemoflagellate Trypanosoma cruzi. Patients in the chronic phase of infection can be categorized into four groups based on the presence of cardiac abnormalities (CARD), gastrointestinal involvement (DIGEST), a combination of both presentations (BOTH), or indeterminate (IND) if Chagas' related pathology is not apparent. Previous studies have indicated that parasite-specific antibody production is important in both resistance to and pathogenesis of disease. The anti-T. cruzi epimastigote stage antibody isotype profiles in the sera of Brazilian patients from each clinical category, as well as from uninfected individuals (UNINF) from the same endemic area were analyzed. Anti-epimastigote immunoglobulin G (IgG)1 and IgG3 levels were strikingly high with titers > or = 1:100,000. Sera from patients in the CARD group had higher levels of IgM than either UNINF or IND individuals, which is consistent with the theory that autoimmunity may contribute to chagasic cardiomyopathy. The IgA levels were higher in sera from patients with gastrointestinal involvement when compared with individuals from any of the other clinical categories as well as from uninfected controls. Interestingly, patients with both digestive and cardiac involvement did not express high serum levels of IgA. However, like patients with cardiac involvement alone, persons with both clinical manifestations produced elevated levels of IgG2 compared with the IND or UNINF groups. These data suggest the presence of complex immunoregulatory processes, most likely related to differential cytokine involvement, which can influence the expression of antibody isotypes and possibly the course of disease.

[Clinico-epidemiologic profile of Chagas disease patients attending an ambulatory referral center and proposal of a model of care for the Chagas patient under the perspective of a comprehensive health care]. / Perfil clínico-epidemiológico de chagásicos atendidos em ambulatório de referência e proposição de modelo de atenção ao chagásico na perspectiva do sus.

A case-control study to analyse clinical and epidemiological data of 842 patientes seen in an outpatient ward reference center for chagas disease in Belo Horizonte, Brazil, from 1985 to 1992. It was verified that these patients were in a average age of 37.78 years; lower literacy regardless of race, and, performed activities that demanded greater muscle effort (p < 0.05). The main mechanism for disease transmission proved to be the vectorial route. Disease-especific complaints prevailed in the above mentioned patients (p < 0.05). The most important abnormalities found in clinical examination were with cardiac sounds (OR: 2.96 95% CI: 1.29-4.09) and the presence of extrasystole (OR: 7.16 95% CI: 1.59-45.07). Imunofluorescence Test was more sensitive (94%) and specific (96%). It also had a PPV of 99% and e NPV of 83%. ELISA test carried out in 43 patientes did not yield false results. Indeterminate chronic phase (56%) or early stages of the disease prevailed. The findings of normal EKGs and abnormalities in 30% of the Holter tests, 41% of the exercise tests, 33% of the ECO tests and, 48% of normal chest x-ray with abnormal ECO, high lights the importance of caring out more detailed exams in specific situations. We hereby propose a care model for the Chagas disease patient, integrated to our State Health Plan stressing serologic tests, and training capable human resources committed to the development of integrated health care and the optimization of our referral and counter-referral system, thus issuing total care to the Chagas disease patient.