Quantification of Immunoglobulin G against Trypanosoma cruzi in Individuals with Chronic Chagas Disease Treated with Nifurtimox and Evaluated in Prolonged Follow-Up

In the indeterminate chronic period of Chagas disease (ChD) the treatment has not been conclusive, because the serological negativization requires many years. This study aims to evaluate the efficacy of nifurtimox (NF) in the treatment of chronic ChD in prolonged follow-up by serological techniques of indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA) IgG comparing 2 groups of patients, treated and non treated. Mann-Whitney test was performed for ELISA and IFA, with significant difference between the groups (P < 0.05). IgG levels were lower in individuals treated compared with untreated patients, indicating chemotherapeutic efficacy in prolonged follow-up.

Ex vivo T-lymphocyte chemokine receptor phenotypes in patients with chronic Chagas disease

Abstract INTRODUCTION: Elucidating the molecules involved in the inflammatory process of chronic Chagas disease may allow identification of treatment targets. METHODS: The ex vivo phenotypic expression of chemokine receptors CCR1, CCR3, CCR4, CCR5, CXCR2, CXCR3, CXCR4, and CXCR5 on the CD4+ and CD8+ T-cells of patients with chronic Chagas cardiomyopathy of varying severity was evaluated using flow cytometry. RESULTS: Differential expression of CD4+CCR3+ and CD8+CCR4+ T-cells was observed in patients with mild cardiac involvement compared, respectively, with patients with severe cardiac and asymptomatic forms of Chagas disease. CONCLUSIONS: These receptors are possibly involved in the pathogenesis of chronic Chagas cardiomyopathy.

Trypanosoma cruzi I genotype among isolates from patients with chronic Chagas disease followed at the Evandro Chagas National Institute of Infectious Diseases (FIOCRUZ, Brazil)

ABSTRACT INTRODUCTION: Trypanosoma cruzi is the etiologic agent of Chagas disease in humans, mainly in Latin America. Trypanosome stocks were isolated by hemoculture from patients followed at Evandro Chagas National Institute of Infectious Diseases (FIOCRUZ) and studied using different approaches. METHODS: For species and genotype identification, the stocks were analyzed by parasitological techniques, polymerase chain reaction assays targeted to specific DNA sequences, isoenzyme patterns, besides sequencing of a polymorphic locus of TcSC5D gene (one stock). RESULTS: The isolates presented typical T. cruzi morphology and usually grew well in routine culture media. Metacyclic trypomastigotes were found in cultures or experimentally infected Triatoma infestans. All isolates were pure T. cruzi cultures, presenting typical 330-bp products from kinetoplast DNA minicircles, and 250 or 200-bp amplicons from the mini-exon non-transcribed spacer. Their genetic type assignment was resolved by their isoenzyme profiles. The finding of TcI in one asymptomatic patient from Paraíba was confirmed by the sequencing assay. TcVI was found in two asymptomatic individuals from Bahia and Rio Grande do Sul. TcII was identified in six patients from Pernambuco, Bahia and Minas Gerais, who presented different clinical forms: cardiac (2), digestive with megaesophagus (1), and indeterminate (3). CONCLUSIONS: The main T. cruzi genotypes found in Brazilian chronic patients were identified in this work, including TcI, which is less frequent and usually causes asymptomatic disease, unlike that in other American countries. This study emphasizes the importance of T. cruzi genotyping for possible correlations between the parasite and patient’ responses to therapeutic treatment or disease clinical manifestations.

Serological based monitoring of a cohort of patients with chronic Chagas disease treated with benznidazole in a highly endemic area of northern Argentina

This study aimed to evaluate well-documented diagnostic antigens, named B13, 1F8 and JL7 recombinant proteins, as potential markers of seroconversion in treated chagasic patients. Prospective study, involving 203 patients treated with benznidazole, was conducted from endemic areas of northern Argentina. Follow-up was possible in 107 out of them and blood samples were taken for serology and PCR assays before and 2, 3, 6, 12, 24 and 36 months after treatment initiation. Reactivity against Trypanosoma cruzi lysate and recombinant antigens was measured by ELISA. The rate of decrease of antibody titers showed nonlinear kinetics with an abrupt drop within the first three months after initiation of treatment for all studied antigens, followed by a plateau displaying a low decay until the end of follow-up. At this point, anti-B13, anti-1F8 and anti-JL7 titers were relatively close to the cut-off line, while anti-T. cruzi antibodies still remained positive. At baseline, 60.8% (45/74) of analysed patients tested positive for parasite DNA by PCR and during the follow-up period in 34 out of 45 positive samples (75.5%) could not be detected T. cruzi DNA. Our results suggest that these antigens might be useful as early markers for monitoring antiparasitic treatment in chronic Chagas disease.

Evaluation of CD4+CD25+ T lymphocyte response time kinetics in patients with chronic Chagas disease after in vitro stimulation with recombinant Trypanosoma cruzi antigens

Introduction CD4+CD25+ T lymphocytes have been implicated in the regulation of host inflammatory response against Trypanosoma cruzi, and may be involved in the clinical course of the disease. Methods Peripheral blood mononuclear cells from patients with chronic Chagas disease were cultured in the presence of T. cruzi recombinant antigens and assayed for lymphocytes at distinct time points. Results It was possible to differentiate clinical forms of chronic Chagas disease at days 3 and 5 according to presence of CD4+CD25+ T cells in cell cultures. Conclusions Longer periods of cell culture proved to be potentially valuable for prospective evaluations of CD4+CD25+ T lymphocytes in patients with chronic Chagas disease. .

Chronic Chagas disease: PCR-xenodiagnosis without previous microscopic observation is a useful tool to detect viable Trypanosoma cruzi

We evaluate the elimination of the microscopic stage of conventional xenodiagnosis (XD) to optimize the parasitological diagnosis of Trypanosoma cruzi in chronic Chagas disease. To this purpose we applied under informed consent two XD cages to 150 Chilean chronic chagasic patients. The fecal samples (FS) of the triatomines at 30, 60 and 90 days post feeding were divided into two parts: in one a microscopic search for mobile trypomastigote and/or epimastigote forms was performed. In the other part, DNA extraction-purification for PCR directed to the conserved region of kDNA minicircles of trypanosomes (PCR-XD), without previous microscopic observation was done. An XD was considered positive when at least one mobile T. cruzi parasite in any one of three periods of incubation was observed, whereas PCR-XD was considered positive when the 330 bp band specific for T. cruzi was detected. 25 of 26 cases with positive conventional XD were PCR-XD positive (concordance 96.2%), whereas 85 of 124 cases with negative conventional XD were positive by PCR-XD (68.5%). Human chromosome 12 detected by Real-time PCR used as exogenous internal control of PCR-XD reaction allowed to discounting of PCR inhibition and false negative in 40 cases with negative PCR-XD. Conclusion: PCR-XD performed without previous microscopic observation is a useful tool for detection of viable parasites with higher efficiency then conventional XD.

Seroprevalence of Helicobacter pylori infection in chagasic and nonchagasic patients from the same geographical region of Brazil / Soroprevalência da infecção por Helicobacter pylori em indivíduos chagásicos e não-chagásicos da mesma região geográfica do Brasil

INTRODUCTION: In this study, we evaluated the seroprevalence of Helicobacter pylori infection among chagasic and non-chagasic subjects as well as among the subgroups of chagasic patients with the indeterminate, cardiac, digestive, and cardiodigestive clinical forms. METHODS: The evaluated subjects were from the Triângulo Mineiro region, Minas Gerais, Brazil. Chagasic patients showed positive reactions to the conventional serological tests used and were classified according to the clinical form of their disease. Immunoglobulin G antibodies specific to H. pylori were measured using a commercial enzyme-linked immunosorbent assay kit. RESULTS: The overall H. pylori prevalence was 77.1% (239/310) in chagasic and 69.1% (168/243) in non-chagasic patients. This difference was statistically significant even after adjustment for age and sex (odds ratio = 1.57; 95% confidence interval, 1.02-2.42; p = 0.04) in multivariate analysis. The prevalence of infection increased with age in the non-chagasic group (p = 0.007, χ2 for trend), but not in the chagasic group (p = 0.15, χ2 for trend). H. pylori infection was not associated with digestive or other clinical forms of Chagas disease (p = 0.27). CONCLUSIONS: Our findings demonstrate that chagasic patients have a higher prevalence of H. pylori compared to non-chagasic subjects; a similar prevalence was found among the diverse clinical forms of the disease. The factors contributing to the frequent co-infection with H. pylori and Trypanosoma cruzi as well as its effects on the clinical outcome deserve further study.

INTRODUÇÃO: No presente estudo, foi comparada a soroprevalência da infecção por Helicobacter pylori entre os indivíduos chagásicos e não-chagásicos, bem como entre subgrupos de chagásicos com as formas clínicas indeterminada, cardíaca, digestiva e cardiodigestiva. MÉTODOS: Os indivíduos avaliados eram provenientes da região do Triângulo Mineiro, Minas Gerais, Brasil. Foram realizados testes sorológicos convencionais para diagnóstico da infecção pelo T. cruzi e os chagásicos foram classificados de acordo com a forma clínica. O diagnóstico de infecção por H. pylori foi estabelecido pela detecção de anticorpos IgG específicos utilizando-se um kit comercial de ELISA. RESULTADOS: A prevalência da infecção por H. pylorifoi 77,1% (239/310) no grupo de pacientes chagásicos e 69,1% (168/243) no grupo de não-chagásicos. Esta diferença foi estatisticamente significativa mesmo após ajuste para idade e sexo (OR = 1,57; 95% CI, 1,02-2,42; p = 0,04) na análise multivariada. A prevalência da infecção aumentou de acordo com a idade no grupo não-chagásicos (p = 0,007, χ2 for trend) mas este aumento não foi observado no grupo dos chagásicos (p = 0,15, χ2 for trend). Não houve associação da infecção por H. pylori com a forma digestiva ou com qualquer outra forma clínica da doença de Chagas (p = 0,27). CONCLUSÕES: Foi demonstrado que pacientes chagásicos apresentam maior prevalência da infecção por H. pylori quando comparados com não-chagásicos, independente da forma clínica da doença. Os fatores que contribuem para a frequente co-infecção Helicobacter pylori e Trypanosoma cruzi, bem como seus efeitos na evolução clínica das doenças associadas devem ser melhor estudados.

Trypanosoma cruzi, hemocultura: uma abordagem prática / Trypanosoma cruzi, hemoculture: a practical approach

JUSTIFICATIVA E OBJETIVOS: A hemocultura permanece útil para diagnosticar a doença de Chagas crônica. O objetivo deste estudo foi comparar a técnica "clássica" e a "modificada" mais usada para essa finalidade no Brasil. MÉTODO: A inoculação de "creme leucocitário" com sedimento de sangue centrifugado caracteriza ambas as técnicas. Amostras provenientes de dois grupos de 137 pacientes chagásicos crônicos foram examinadas. A "clássica" utiliza 10 mL de sangue; a "modificada", 30 mL. RESULTADOS: A técnica "modificada" mostrou-se mais sensível do que a "clássica". CONCLUSÃO: Sugere-se o uso rotineiro da técnica "modificada".

BACKGROUND AND OBJECTIVES: Hemoculture remains a valuable tool for the diagnosis of chronic Chagas disease. We tested the two techniques routinely used in Brazil. METHOD: The "modified" technique includes the inoculation of "buffy coat" and centrifuged blood sediment from a 30 mL sample, the serum being washed out after centrifugation and replaced by equal volume of culture medium; the "classic" one requires the inoculation of centrifuged blood sediment plus "buffy coat" from a 10 mL sample. RESULTS: A higher sensitivity of the "modified" technique was observed when the results of two samples of 137 chronic Chagas disease patients were compared. CONCLUSION: The routine use of the "modified" technique should be preferred.

Efects of plasma corticosteroid concentration on the osmotic threshold for vasopressin releasing in Chagas' disease

The osmotic threshold for vasopressin release was studied in normal patients (n = 7) and in patients with the chronic form of Chagas'disease (n = 11). Positive correlation between osmotic threshold and plasma cortisol concentration was obtained for the Controls (y1 = 273,30 + 0,75x i; r = 0,78;P < 0,05), suggesting a modulating effect of cortisol on vasopressin release. The lack of correlation between the two parameters for the chronic chagasic patients was interpreted, on the basis of the general denervation associated with Chagas ' disease, to be the result of neuronal destruction in hypothalamic and/or extrahypothalamic centers related to the secretory control of vasopressin.

O limiar osmótico para liberação da vaso- pressina foi estudado em pacientes normais (n = 7) e em pacientes com a forma crônica da moléstia de Chagas (n = 11). Verificou-se a existência de uma correlação positiva entre o limiar osmótico e a concentração plasmática do cortisol endógeno para os controles (y1 = 273,30 + 0,75 x i; r = 0,78, p < 0,05), sugerindo um efeito modulador do cortisol na liberação da vasopressina. A falta de correlação entre os dois parâmetros, para os pacientes chagásicos crônicos, interpretou-se, baseando-se na desnervação geral associada com a doença de Chagas, como sendo o resultado da destruição neuronal em centros hipotalâmicos ejou extra-hipotalâmicos relacionados com o controle secretário da vosopressina.