Comportamento da parasitemia pelo Trypanosoma cruzi em chagásicos crônicos durante 13 anos

Castro, Cleudson; Macêdo, Vanize; Prata, Áluízio

doi:10.1590/s0037-86821999000200007

Cited by 16 publications

(8 citation statements)

References 12 publications

(6 reference statements)

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“…Certainly, to determine if these in vitro conditions somehow mimic the T cell environment in human Chagas diseases is challenging; nonetheless, recent evidence suggests that the parasitemia in the chronic stages of the disease is not static, and in fact can occasionally reach high values [56]–[58]. Moreover, our results showed that CARD CP had lower CD8+ proliferative response to PHA, low level of T cells expressing CD28+ cells, lower expression CD3ζ (CD3ζ bright /CD3ζ dim Ratio) and still higher fractions of activated T cells than individuals with non-chagasic cardiomyopathy; suggesting that parasite persistence, more than the systemic changes derived from heart failure, are associated with these cellular immune abnormalities.…”

Section: Discussionmentioning

confidence: 99%

T Lymphocytes from Chagasic Patients Are Activated but Lack Proliferative Capacity and Down-Regulate CD28 and CD3ζ

et al. 2013

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BackgroundChronic persistent infections have been associated with T lymphocytes functional impairment. The aim of this study was to compare the activation status, the proliferative potential and the expression of CD28 and CD3ζ chain on T lymphocytes between chronic chagasic patients and uninfected controls.Methodology/Principal FindingsForty-two chronic chagasic patients, 28 healthy individuals and 32 non-chagasic cardiomyopathy donors were included. Peripheral blood was marked for CD3, CD4, CD8, HLA-DR, CD28, CD38 and intracellular CD3ζ. Peripheral blood mononuclear cells were stained with carboxyfluorescein diacetate succinimidylester and incubated with T. cruzi lysate or phytohemagglutinin for five days. Cells from 3 healthy controls were incubated with T. cruzi trypomastigotes separated with transwells; and the expression of CD3ζ chain and proliferation index was determined. Heart-infiltrating cells from two chronic chagasic patients were tested for the aforementioned cellular markers. Chagasic patients displayed higher frequencies of CD4+/HLA-DR+/CD38+ (8.1%±6.1) and CD8+/HLA-DR+/CD38+ (19.8±8.9) T cells in comparison with healthy (1.6±1.0; 10.6±8.0) and non-chagasic cardiomyopathy donors (2.9±2.9; 5.8±6.8). Furthermore, the percentage of CD4+ activated T cells was higher in chagasic patients with cardiac involvement. CD8+ T cells proliferation index in chagasic donors (1.7±0.3) was lower when compared with healthy (2.3±0.3) and non-chagasic cardiomyopathy individuals (3.1±1.1). The frequencies of CD4+/CD28+ and CD8+/CD28+ T cells, as well as the CD3ζbright/CD3ζdim% ratios in CD4+ and CD8+ were lower in chagasic patients when compared with both control groups. The CD3ζbright/CD3ζdim% ratio and proliferative indexes for CD4+ and CD8+ T lymphocytes decreased gradually in those cells cultivated with parasites and displayed lower values than those incubated with medium alone. Finally, heart-infiltrating T cells from two T. cruzi infected patients also expressed activation markers and down-regulate CD28 and CD3ζ.ConclusionsCD8+ T lymphocytes from chagasic donors displayed reduced proliferative capacity, which might be associated with CD3ζ down-regulation and diminished CD28 expression on CD4 T cells.

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Section: Discussionmentioning

confidence: 99%

T Lymphocytes from Chagasic Patients Are Activated but Lack Proliferative Capacity and Down-Regulate CD28 and CD3ζ

et al. 2013

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“…T. cruzi circulates in very small amounts at the chronic phase and dynamics about its circulation is not predictable [141,142]. It is possible that, even if a patient is infected, the collected sample does not have an adequate amount of the parasite DNA leading the test to a negative or undetectable result.…”

Section: Discussionmentioning

confidence: 99%

ELISA versus PCR for diagnosis of chronic Chagas disease: systematic review and meta-analysis

et al. 2010

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BackgroundMost current guidelines recommend two serological tests to diagnose chronic Chagas disease. When serological tests are persistently inconclusive, some guidelines recommend molecular tests. The aim of this investigation was to review chronic Chagas disease diagnosis literature and to summarize results of ELISA and PCR performance.MethodsA systematic review was conducted searching remote databases (MEDLINE, LILACS, EMBASE, SCOPUS and ISIWeb) and full texts bibliography for relevant abstracts. In addition, manufacturers of commercial tests were contacted. Original investigations were eligible if they estimated sensitivity and specificity, or reliability -or if their calculation was possible - of ELISA or PCR tests, for chronic Chagas disease.ResultsHeterogeneity was high within each test (ELISA and PCR) and threshold effect was detected only in a particular subgroup. Reference standard blinding partially explained heterogeneity in ELISA studies, and pooled sensitivity and specificity were 97.7% [96.7%-98.5%] and 96.3% [94.6%-97.6%] respectively. Commercial ELISA with recombinant antigens studied in phase three investigations partially explained heterogeneity, and pooled sensitivity and specificity were 99.3% [97.9%-99.9%] and 97.5% [88.5%-99.5%] respectively. ELISA's reliability was seldom studied but was considered acceptable. PCR heterogeneity was not explained, but a threshold effect was detected in three groups created by using guanidine and boiling the sample before DNA extraction. PCR sensitivity is likely to be between 50% and 90%, while its specificity is close to 100%. PCR reliability was never studied.ConclusionsBoth conventional and recombinant based ELISA give useful information, however there are commercial tests without technical reports and therefore were not included in this review. Physicians need to have access to technical reports to understand if these serological tests are similar to those included in this review and therefore correctly order and interpret test results. Currently, PCR should not be used in clinical practice for chronic Chagas disease diagnosis and there is no PCR test commercially available for this purpose. Tests limitations and directions for future research are discussed.

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“…Few studies were performed to show the parasitological profile of nontreated, chronic-phase, infected individuals, mostly by xenodiagnosis (Coura et al 1991;Castro et al 1999;Castro and Prata 2000) and by blood culture (Castro et al 2002). To obtain such a profile, it is essential to study the same individual on different occasions because it is well-known that the chances to obtain positive results increase proportionally to the number of examinations performed (Luquetti and Rassi 2000).…”

Section: Treatment Evaluation By Parasitological Methodsmentioning

confidence: 99%

Detection of parasitemia profiles by blood culture after treatment of human chronic Trypanosoma cruzi infection

et al. 2006

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The change in parasitemia profile, measured by sequential blood cultures of 27 benznidazole (Bz) treated patients compared with 13 untreated patients, on the chronic phase of chagas disease, is described. All patients were adults (age limits: 23-88) with positive serology (three tests); 23 of them were females. All patients were submitted to six blood cultures, three before and three after Bz treatment. The parasitemia was classified as nondetected (with three negative blood cultures), medium (one positive culture in three), and high (two or three positive cultures). From the eight patients with nondetected parasitemia before Bz, seven still had the same profile and only one switched to medium; from eight with medium parasitemia, seven shifted to nondetected, and one to high parasitemia. From the 11 patients with high parasitemia before Bz, ten converted to nondetected and only one was positive after Bz. Nineteen of the 27 patients changed the parasitemia profile (70.4%), and the rate of therapeutic failure was 11.1% (3/27) during the first 24 months of follow-up after Bz. The shift to nondetected parasitemia profile was from 8/27 to 24/27 patients after Bz treatment for the first 2 years. Only 46.2% (6/13) of the nontreated individuals changed the parasitemia profile. We conclude that there is a strong trypanocide effect of Bz (88.8%) and a rate of therapeutic failure of 11.1% during the first 2 years after trypanocidal treatment.

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Comportamento da parasitemia pelo Trypanosoma cruzi em chagásicos crônicos durante 13 anos

Cited by 16 publications

References 12 publications

T Lymphocytes from Chagasic Patients Are Activated but Lack Proliferative Capacity and Down-Regulate CD28 and CD3ζ

T Lymphocytes from Chagasic Patients Are Activated but Lack Proliferative Capacity and Down-Regulate CD28 and CD3ζ

ELISA versus PCR for diagnosis of chronic Chagas disease: systematic review and meta-analysis

Detection of parasitemia profiles by blood culture after treatment of human chronic Trypanosoma cruzi infection

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