Associação entre os níveis plasmáticos de TNF-α, IFN-γ, IL-10, óxido nítrico e os isotipos de IgG específicos nas formas clínicas da doença de Chagas crônica

Cytokine profile levels and their relationship with parasitemia and cardiomyopathy in people with Chagas disease in Spain. A prospective observational study

Immunoregulatory networks may have a role in controlling parasitemia in the chronic phase of human Chagas disease. The aim was to describe the serum cytokine profile of Trypanosoma cruzi in chronically infected patients and to evaluate its relationship with parasitemia and Chagas cardiomyopathy.This prospective observational study included adult patients with chronic Chagas disease. Demographic and clinical data were collected, and peripheral blood samples were used to perform T. cruzi real-time polymerase chain reaction (RT-PCR) and determine the serum cytokine profile.Fifty-eight patients were included; 17 (29.3%) had positive RT-PCR results. This group had a higher median concentration of TNF-α (p = 0.003), IL-6 (p = 0.021), IL-4 (p = 0.031), IL-1β (p = 0.036), and IL-17A (p = 0.043) than those with a negative RT-PCR. Patients with cardiac involvement had a higher median concentration of IL-5 (p = 0.016) than those without.These results reinforce the key role that cytokines play in Chagas disease patients with parasitemia and cardiac involvement.

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.

Correlation of transforming growth factor-β1 and tumour necrosis factor levels with left ventricular function in Chagas disease

BACKGROUND

Transforming growth factor β1 (TGF-β1) and tumour necrosis factor (TNF) have been implicated in Chagas disease pathophysiology and may correlate with left ventricular (LV) function.

OBJECTIVES

We determined whether TGF-β1 and TNF serum levels correlate with LV systolic and diastolic functions and brain natriuretic peptide (BNP) serum levels in chronic Chagas disease.

METHODS

This cross-sectional study included 152 patients with Chagas disease (43% men; 57 ± 12 years old), classified as 53 patients with indeterminate form and 99 patients with cardiac form (stage A: 24, stage B: 25, stage C: 44, stage D: 6). TGF-β1, TNF, and BNP were determined by enzyme-linked immunosorbent assay ELISA. Echocardiogram was used to determine left atrial and LV diameters, as well as LV ejection fraction and diastolic function.

FINDINGS

TGF-b1 serum levels were lower in stages B, C, and D, while TNF serum levels were higher in stages C and D of the cardiac form. TGF-β1 presented a weak correlation with LV diastolic function and LV ejection fraction. TNF presented a weak correlation with left atrial and LV diameters and LV ejection fraction.

CONCLUSIONS

TNF is increased, while TGF-β1 is decreased in the cardiac form of chronic Chagas disease. TNF and TGF-β1 serum levels present a weak correlation with LV systolic and diastolic function in Chagas disease patients.

Evolution of anti-Trypanosoma cruzi antibody production in patients with chronic Chagas disease: Correlation between antibody titers and development of cardiac disease severity

Chagas disease is one of the most important endemic infections in Latin America affecting around 6–7 million people. About 30–50% of patients develop the cardiac form of the disease, which can lead to severe cardiac dysfunction and death. In this scenario, the identification of immunological markers of disease progression would be a valuable tool for early treatment and reduction of death rates. In this observational study, the production of anti-Trypanosoma cruzi antibodies through a retrospective longitudinal follow-up in chronic Chagas disease patients´ cohort and its correlation with disease progression and heart commitment was evaluated. Strong inverse correlation (ρ = -0.6375, p = 0.0005) between anti-T. cruzi IgG₁ titers and left ventricular ejection fraction (LVEF) in chronic Chagas cardiomyopathy (CCC) patients were observed after disease progression. Elevated levels of anti-T. cruzi IgG₃ titers were detected in all T. cruzi-infected patients, indicating a lack of correlation of this IgG isotype with disease progression. Furthermore, low levels of anti-T. cruzi IgG₂, IgG₄, and IgA were detected in all patients through the follow-up. Although without statistical significance anti-T. cruzi IgE tends to be more reactive in patients with the indeterminate form (IND) of the disease (p = 0.0637). As this study was conducted in patients with many years of chronic disease no anti-T. cruzi IgM was detected. Taken together, these results indicate that the levels of anti-T. cruzi IgG₁ could be considered to seek for promising biomarkers to predict the severity of chronic Chagas disease cardiomyopathy.

Trypanosoma cruzi is the etiological agent of Chagas disease that affects about 7 million people in Latin America, being considered one of the most important neglected diseases of developing countries. Chronic Chagas disease might be present in different forms as an asymptomatic indeterminate form or even with severe cardiac commitment, known as chronic Chagas cardiomyopathy. In fact, the cardiac form can lead to death due to disease progression. Seeking for biomarkers of cardiomyopathy progression has become important to understand the cardiac progression and to predict or even prevent the disease worsening and to improve the quality of life of affected individuals. In this work, we followed the anti-T. cruzi antibody profile in a retrospective longitudinal study in a cohort of chronic Chagas disease patients, and further correlate with heart commitment and cardiac disease progression. We found an inverse correlation between anti-T. cruzi IgG₁ titers and cardiac disease severity in patients with progressive disease. These data suggest that anti-T. cruzi IgG₁ levels could be considered a suitable candidate tool for early identification of cardiac disease progression.

Interleukin-10 and tumour necrosis factor-alpha serum levels in chronic Chagas disease patients

In Chagas disease, chronically infected individuals may be asymptomatic or may present cardiac or digestive complications, and it is well known that the human immune response is related to different clinical manifestations. Different patterns of cytokine levels have been previously described in different clinical forms of this disease, but contradictory results are reported. Our aim was to evaluate the serum levels of interleukin-10 and tumour necrosis factor-alpha in patients with asymptomatic and cardiac Chagas disease. The serum interleukin-10 levels in patients with cardiomyopathy were higher than those in asymptomatic patients, mainly in those without heart enlargement. Although no significant difference was observed in serum tumour necrosis factor-alpha levels among the patients, we found that cardiac patients also present high levels of this cytokine, largely those with heart dilatation. Therefore, these cytokines play an important role in chronic Chagas disease cardiomyopathy. Follow-up investigations of these and other cytokines in patients with chronic Chagas disease need to be conducted to improve the understanding of the immunopathology of this disease.

Cytokine profiling in Chagas disease: towards understanding the association with infecting Trypanosoma cruzi discrete typing units (a BENEFIT TRIAL sub-study)

BACKGROUND

Chagas disease caused by the protozoan Trypanosoma cruzi is an important public health problem in Latin America. The immunological mechanisms involved in Chagas disease pathogenesis remain incompletely elucidated. The aim of this study was to explore cytokine profiles and their possible association to the infecting DTU and the pathogenesis of Chagas disease.

METHODS

109 sero-positive T. cruzi patients and 21 negative controls from Bolivia and Colombia, were included. Flow cytometry assays for 13 cytokines were conducted on human sera. Patients were divided into two groups: in one we compared the quantification of cytokines between patients with and without chronic cardiomyopathy; in second group we compared the levels of cytokines and the genetic variability of T. cruzi.

RESULTS

Significant difference in anti-inflammatory and pro-inflammatory cytokines profiles was observed between the two groups cardiac and non-cardiac. Moreover, serum levels of IFN-γ, IL-12, IL-22 and IL-10 presented an association with the genetic variability of T.cruzi, with significant differences in TcI and mixed infections TcI/TcII.

CONCLUSION

Expression of anti-inflammatory and pro-inflammatory cytokines may play a relevant role in determining the clinical presentation of chronic patients with Chagas disease and suggests the occurrence of specific immune responses, probably associated to different T. cruzi DTUs.

[Endothelial function and high-sensitivity C-reactive protein levels in patients with Chagas disease living in a nonendemic area]

INTRODUCTION AND OBJECTIVES

The number of patients with Chagas disease in Spain has increased significantly. Chronic inflammation and endothelial dysfunction have been considered among the physiopathological mechanisms of Chagas heart disease. However, there have been conflicting data from clinical studies. Our purpose was to assess endothelial function and systemic levels of nitric oxide and high-sensitivity C-reactive protein in patients with the indeterminate form and with chronic Chagas cardiomyopathy living in a nonendemic area.

METHODS

Flow-mediated endothelium-dependent vasodilatation and nitroglycerin-mediated vasodilatation were assessed with high-resolution ultrasound of the brachial artery in 98 subjects (32 with the indeterminate form, 22 with chronic Chagas cardiomyopathy and 44 controls). Nitric oxide and high-sensitivity C-reactive protein levels were measured in peripheral venous blood.

RESULTS

Mean age was 37.6 ± 10.2 years and 60% were female. Nitroglycerin-mediated vasodilatation was significantly reduced in chronic Chagas cardiomyopathy compared to controls (median 16.8% vs 22.5%; P=.03). No significant differences were observed in flow-mediated vasodilatation and nitric oxide levels, although a trend towards lower flow-mediated vasodilatation after correction by baseline brachial artery diameter was observed in chronic Chagas cardiomyopathy. Levels of C-reactive protein were significantly higher in patients with the indeterminate form and with Chagas cardiomyopathy compared with controls (P<.05).

CONCLUSIONS

Reduced nitroglycerin-mediated vasodilatation suggesting dysfunction of vascular smooth muscle cells was found in patients with chronic Chagas cardiomyopathy living in a nonendemic area. Higher C-reactive protein levels were observed in the indeterminate form and early stages of chronic Chagas cardiomyopathy, which could be related to the inflammatory response to the infection or early cardiovascular involvement.

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.