IgG Subclass Analysis in Patients with Chagas Disease 4 Years After Benznidazole Treatment.

BACKGROUND: In humans, Trypanosoma cruzi infection is controlled by a complex immune response. Immunoglobulin G (IgG) is important for opsonizing blood trypomastigotes, activating the classic complement pathway, and reducing parasitemia. The trypanocidal activity of benznidazole is recognized, but its effects on the prevention and progression of Chagas disease is not well understood OBJECTIVE: We aimed to evaluate the levels of total IgG and cross-specific IgG subclasses in patients with chronic Chagas disease of different clinical forms before and after 4 years of benznidazole treatment. METHODS: Eight individuals with the indeterminate form and nine with the cardiac form who completed the treatment protocol were evaluated. The levels of total IgG and IgG1, IgG2, IgG3, and IgG4 isotypes were quantified in the serum of each individual using the fluorescent immunosorbent assay. The results are expressed as relative fluorescence unit. RESULTS: Patients with chronic Chagas disease presented decreased levels of total IgG at 48 months after benznidazole treatment. Increased IgG1 and decreased IgG3 levels were observed in patients with the cardiac form and those with exacerbated clinical forms. In addition, a decrease in the IgG3/IgG1 ratio was observed in individuals with the cardiac form of Chagas disease. CONCLUSIONS: Benznidazole administration in the chronic phase differentially changes IgG subclasses in patients with cardiac and indeterminate forms, and monitoring the IgG3 level may indicate the possible prognosis to the cardiac form or worsening of the already established clinical form.

T-Cell Immunophenotyping and Cytokine Production Analysis in Patients with Chagas Disease 4 Years after Benznidazole Treatment.

The major problem with Chagas disease is evolution of the chronic indeterminate form to a progressive cardiac disease. Treatment diminishes parasitemia but not clinical progression, and the immunological features involved are unclear. Here, we studied the clinical course and the immune response in patients with chronic-phase Chagas disease at 48 months after benznidazole treatment. Progression to the cardiac form of Chagas disease or its aggravation was associated with higher in vitro antigen-specific production of interferon gamma (IFN-γ) in patients with cardiac Chagas disease than in patients with the indeterminate form. Predominance of IFN-γ production over interleukin-10 (IL-10) production in antigen-specific cultures was associated with cardiac involvement. Significantly higher numbers of antigen-specific T helper 1 cells (T-Bet+ IFN-γ+) and a significantly higher IFN-γ+/IL-10+ ratio were observed in patients with cardiac Chagas disease than in patients with the indeterminate form. Cardiac damage was associated with higher numbers of T helper cells than cytotoxic T lymphocytes producing IFN-γ. Patients with cardiac Chagas disease had predominant CD25- and CD25low T regulatory (Treg) subpopulations, whereas patients with the indeterminate form manifested a higher relative mean percentage of CD25high Treg subpopulations. These findings suggest that at 48 months after benznidazole treatment, the disease can worsen or progress to the cardiac form. The progression may be related to increased IFN-γ production (mostly from CD4+ T cells) relative to IL-10 production and increased Treg percentages. Patients with the indeterminate form of Chagas disease show a more balanced ratio of proinflammatory and anti-inflammatory cytokines.

Cardiac autonomic modulation and long-term use of amiodarone in patients with chronic Chagasic cardiopathy.

BACKGROUND: Patients with chronic Chagas cardiopathy (CCC), which may be associated with cardiac arrhythmias, frequently use amiodarone, an antiarrhythmic drug that, experimentally, appears to modulate the cardiac autonomic function. OBJECTIVE: The present cross-sectional observational study aimed to evaluate autonomic cardiac modulation in patients with CCC undergoing chronic amiodarone therapy. METHODS: Three groups were investigated: Group 1 included patients with CCC not treated with amiodarone (n = 27); Group 2 included patients with CCC with prolonged use (at least 6 months) of amiodarone (n = 16); and Group 3 included non-Chagasic control patients (n = 23). All patients underwent a complete clinical and laboratory assessment, followed by autonomic function tests, consisting of a basal continuous electrocardiogram in the resting supine position for 10 minutes, followed by a change the orthostatic posture for a further 5 minutes. Heart rate variability (HRV) parameters (median and interquartile interval) were quantified using linear methods in the time- and frequency-domains (autoregressive spectral analysis) and nonlinear methods, including symbolic analysis. RESULTS: Patients with CCC using amiodarone had changes in HRV suggestive of an offset in the sympatho-vagal balance with a vagal modulation predominance (normalized HF, 49.7[27.4] vs 31.1[22.8] [P < 0.05]; and percentage 2V, 40.1 [14.6] vs 21.5 [13.4] [P < 0.05] vs untreated CCC group). These changes were further accompanied by increases in parameters indicative of greater complexity of HRV. CONCLUSIONS: The deviation in the sympatho-vagal balance and the increase in the complexity of HRV strongly suggest that amiodarone may have a cardioprotective effect, in addition to its antiarrhythmic effects, which could increase the survival of these patients.

Association between the lymphotoxin-alpha gene polymorphism and chagasic cardiopathy.

Lymphotoxin-alpha (LT-alpha or LTA) is an inflammatory cytokine that is involved in the organization and maintenance of the inflammatory process and in the arrangement of cells at the site of inflammation. These features suggest an important role in the development of chronic Chagas' disease, especially the cardiac form. The objective of this study was to evaluate LT-alpha genetics and its biological role in chronic Chagas' disease. A total of 284 subjects were studied. The LT-alpha single-nucleotide polymorphism (+252) was analyzed by the polymerase chain reaction-restriction fragment length polymorphism and expression by enzyme-linked immunosorbent assay in culture supernatants and in individual T lymphocytes by flow cytometry. The risk of developing the cardiac form was 2.8 times higher among carriers of genotype GG and 2.4 times among carriers of genotype GA when compared to subjects carrying genotype AA. Seropositive subjects carrying the G allele produced significantly higher levels of LT-alpha. The cytokine was mainly expressed by CD8(+) T lymphocytes in the absence of any stimulus and after stimulation with the Trypanosoma cruzi antigen. This study provides genetic and biological evidence for an important role of LT-alpha in the development of the cardiac form of Chagas' disease.

Immunophenotyping of circulating T cells in a mucosal leishmaniasis patient coinfected with HIV.

HIV coinfection modifies the clinical course of leishmaniasis by promoting a Th2 pattern of cytokine production. However, little information is available regarding the lymphocytic response in untreated coinfected patients. This work presents the immunophenotyping of Leishmania-stimulated T cells from a treatment-naÏve HIV+ patient with ML. Leishmania braziliensis antigens induced CD69 expression on CD3+CD4+ and CD3+CD8+ cells. It also increased IL-4 intracellular staining on CD3+CD4+GATA3- population and decreased the percentage of CD3+CD4+IL-17+ cells. This suggests that modulations in the IL-4R/STAT6 pathway and the Th17 population may serve as parasitic evasion mechanisms in HIV/ML. Further studies are required to confirm these results.

Immunophenotyping of circulating T cells in a mucosal leishmaniasis patient coinfected with HIV / Immunofenotipagem de células T circulantes em um paciente com leishmaniose mucosa co-infectado com HIV

HIV coinfection modifies the clinical course of leishmaniasis by promoting a Th2 pattern of cytokine production. However, little information is available regarding the lymphocytic response in untreated coinfected patients. This work presents the immunophenotyping of Leishmania-stimulated T cells from a treatment-naÏve HIV+ patient with ML. Leishmania braziliensis antigens induced CD69 expression on CD3+CD4+ and CD3+CD8+ cells. It also increased IL-4 intracellular staining on CD3+CD4+GATA3- population and decreased the percentage of CD3+CD4+IL-17+ cells. This suggests that modulations in the IL-4R/STAT6 pathway and the Th17 population may serve as parasitic evasion mechanisms in HIV/ML. Further studies are required to confirm these results.

A co-infecção por HIV modifica o curso clínico da leishmaniose ao promover aumento no perfil Th2 de produção de citocinas. No entanto, há pouca informação a respeito da resposta linfocitária em pacientes co-infectados sem tratamento. Neste trabalho, foi realizada a imunofenotipagem de células T estimuladas com antígenos de Leishmania braziliensis em paciente não tratado HIV+ e com leishmaniose mucosa. Os resultados mostraram aumento na expressão de CD69 em células CD3+CD4+ e CD3+CD8+. Além disso, foi observado aumento de IL-4 na população de linfócitos CD3+CD4+GATA3- e diminuição no percentual de células CD3+CD4+IL-17+. Estes resultados sugerem que a modulação da via IL-4R/STAT6 e da população de células Th17 funcione como mecanismo de evasão parasitária em HIV/LM. Estudos futuros são necessários para confirmar estes resultados.

Genetic and functional role of TNF-alpha in the development Trypanosoma cruzi infection.

TNF-alpha plays an important role in trypanocidal mechanisms and is related to tissue injury. This cytokine has been detected in the heart of human chagasic patients where it is associated with tissue damage. This study investigated whether TNF-alpha levels and the presence of genetic polymorphisms are associated with the presence of T. cruzi infection and/or with the development of the cardiac form in chronic chagasic patients. Genomic DNA of 300 subjects from an endemic area was extracted and analyzed by PCR using specific primers. TNF-alpha was assayed in culture supernatants by ELISA. An association was observed between the absence of the TNF-238A allele and negative serology. Furthermore, seropositive individuals carrying the TNF-238A allele produced significantly higher TNF-alpha levels without stimulation (p=0.04) and after stimulation with LPS (p=0.007) and T. cruzi antigens (p=0.004). The present results suggest that the polymorphism at position -238 influences susceptibility to infection and that this allele is associated with higher TNF-alpha production in seropositive individuals.

The relationship between heart rate variability and serum cytokines in chronic chagasic patients with persistent parasitemia.

BACKGROUND: Persistent parasitemia, immunological, and autonomic nervous system impairments may play an important role in the evolution and clinical outcome of the chronic phase of Chagas' disease by triggering functional cardiovascular changes. METHODS: Three groups were evaluated: 17 chronic chagasic patients with the indeterminate form (IChD), 12 chronic chagasic patients with cardiac forms (ChHD), and 29 individuals as a healthy control group. Parasitemia was assessed by polymerase chain reaction; hemoculture, heart rate variability by linear and nonlinear methods, and interleukin (IL)-1ß, IL-4, IL-6, IL-10, IL-12, IL-13, IL-17, and tumor necrosis factor-α, and interferon (IFN)-γ serum cytokines were assessed by enzyme-linked immune assay. RESULTS: Twenty-nine chronic chagasic patients were positive for parasitemia (17 IChD and 12 ChHD). Heart rate variability parameters in baseline condition and after cold face test were significantly decreased in chagasic patients compared to controls. Tilt tests showed no alteration. However, using nonlinear indices, ChHD patients presented lower values compared to IChD and controls. Differences in the expression of serum cytokines were observed between chagasic patients and controls. However, among the groups, ChHD presented higher median values of IL-10 and lower of IFN-γ compared to IChD. CONCLUSION: Both chagasic groups present an autonomic impairment using linear methods. The nonlinear methods revealed that the ChHD group had a higher cardiovascular risk. Serum cytokine concentrations between chagasic patients were similar. However, ChHD showed higher concentrations of IL-10 and lower of IFN-γ, suggesting some established process of immune regulation.

[Epidemiological analysis of patients coinfected with Chagas disease and cysticercosis]. / Análisis epidemiológico de pacientes coinfectados con enfermedad de Chagas y cisticercosis.

INTRODUCTION: Among inhabitants of endemic areas in the developing world, infection with the larva of Taenia solium (cysticercosis) may possibly induce a state of immunosuppression in the host, thereby increasing the risk of multiple infections after exposure to other parasites, such as Trypanosoma cruzi. OBJECTIVE: Increase in the epidemiological occurrence of infection was assessed for Trypanosoma cruzi (Chagas disease) in patients with cysticercosis. MATERIALS AND METHODS: At the University Hospital in Uberaba, Minas Gerais, Brazil, data were obtained from autopsies performed between 1970-2004 on 1,501 subjects older than 15 years of age. Cases were divided into four groups: (1) no infection, (2) cysticercosis only, (3) Chagas disease only, and (4) cysticercosis coinfected with Chagas disease. Race, gender and age data were analyzed. RESULTS: More than half of the cases showed no infection (848 cases or 56.5%); Chagas disease was found in 611 patients (40.7%); 72 cases (4.8% of the autopsies) had cysticercosis and 30 of them (41.7%) were co-infected with Chagas disease. White race and male gender were predominant in all groups. The youngest median age was found in the non-infected group (46 years), followed by those with Chagas disease without cysticercosis (49 years) and those coinfected with cysticercosis and Chagas disease (57.5 years). CONCLUSION: Presumably, all patients had a similar exposure to both parasites. However, in this study population, Chagas disease was approximately 10 times more frequent in patients coinfected with cysticercosis.

Análisis epidemiológico de pacientes coinfectados con enfermedad de Chagas y cisticercosis / Epidemiological analysis of patients coinfected with Chagas disease and cysticercosis

Introducción. Se ha sugerido que la infección por larvas de Taenia solium (cisticercosis) podría inducir un estado de inmunosupresión en el huésped, aumentando el riesgo de adquirir infecciones múltiples después de estar expuesto a otros parásitos, entre ellos Trypanosoma cruzi, particularmente entre habitantes de áreas endémicas en países en desarrollo. Objetivos. Evaluar un posible aumento en la presentación endémica de infección por T. cruzi (enfermedad de Chagas) en pacientes con cisticercosis. Materiales y métodos. Se estudiaron 1.501 autopsias de individuos mayores de 15 años de edad del Hospital Universitario de Uberaba, Minas Gerais, Brasil, 1970-2004. Se dividieron los casos en cuatro grupos: (1) sin infección, (2) con cisticercosis, (3) con enfermedad de Chagas y (4) coinfectados con cisticercosis y enfermedad de Chagas. Se analizaron las variables de raza, sexo y edad. Resultados. Más de la mitad de todos los casos no presentaban infección (848 casos o 56,5%); 611 pacientes (40,7%) tenían enfermedad de Chagas; 72 casos (4,8% de las autopsias) tenían cisticercosis y 30 (41,7%) presentaron coinfección de cisticercosis con enfermedad de Chagas. La raza blanca y el sexo masculino fueron predominantes en todos los grupos. La mediana de edad más joven fue encontrada en el grupo sin infección (46 años), seguido por aquéllos que presentaban enfermedad de Chagas (49 años) y por aquéllos con coinfección de cisticercosis y enfermedad de Chagas (57,5 años). Conclusión. En teoría, todos los pacientes tuvieron un riesgo similar de exposición para ambos parásitos. Sin embargo, este trabajo demuestra que, en la población estudiada, la enfermedad de Chagas fue, aproximadamente, 10 veces más frecuente en los casos coinfectados con cisticercosis.

Introduction. Among inhabitants of endemic areas in the developing world, infection with the larva of Taenia solium (cysticercosis) may possibly induce a state of immunosuppression in the host, thereby increasing the risk of multiple infections after exposure to other parasites, such as Trypanosoma cruzi. Objective. Increase in the epidemiological occurrence of infection was assessed for Trypanosoma cruzi (Chagas disease) in patients with cysticercosis. Materials and methods. At the University Hospital in Uberaba, Minas Gerais, Brazil, data were obtained from autopsies performed between 1970-2004 on 1,501 subjects older than 15 years of age. Cases were divided into four groups: (1) no infection, (2) cysticercosis only, (3) Chagas disease only, and (4) cysticercosis coinfected with Chagas disease. Race, gender and age data were analyzed. Results. More than half of the cases showed no infection (848 cases or 56.5%); Chagas disease was found in 611 patients (40.7%); 72 cases (4.8% of the autopsies) had cysticercosis and 30 of them (41.7%) were co-infected with Chagas disease. White race and male gender (46 years), followed by those with Chagas disease without cysticercosis (49 years) and those coinfected with cysticercosis and Chagas disease (57.5 years). Conclusion. Presumably, all patients had a similar exposure to both parasites. However, in this study population, Chagas disease was approximately 10 times more frequent in patients co-infected with cysticercosis.

Diphyllobothrium latum infection in a non-endemic country: case report.

Diphyllobothriasis, which is rarely described in Brazil, was reported initially as a travelers disease and as an accidental infection in individuals who ate raw freshwater fish. This report aims to present the case of a 20-year-old patient with confirmed Diphyllobothrium latum infection.

Diphyllobothrium latum infection in a non-endemic country: case report / Infecção pelo Diphyllobothrium latum em país não endêmico: relato de caso

Diphyllobothriasis, which is rarely described in Brazil, was reported initially as a travelers’ disease and as an accidental infection in individuals who ate raw freshwater fish. This report aims to present the case of a 20-year-old patient with confirmed Diphyllobothrium latum infection.

A difilobotríase, raramente descrita no Brasil, foi referida inicialmente como doença de viajantes e como infecção acidental em indivíduos que se alimentam com peixe cru de água doce. Este relato objetiva apresentar o caso de uma paciente de 20 anos com infecção confirmada pelo Diphyllobothrium latum.