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Vizcaya D, Grossmann U, Kleinjung F, Zhang R, Suzart-Woischnik K, Seu S, Ramirez T, Colmegna L, Ledesma O. Serological response to nifurtimox in adult patients with chronic Chagas disease: An observational comparative study in Argentina. PLoS Negl Trop Dis 2021; 15:e0009801. [PMID: 34606501 PMCID: PMC8489720 DOI: 10.1371/journal.pntd.0009801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/09/2021] [Indexed: 11/18/2022] Open
Abstract
Nifurtimox is indicated in Chagas disease but determining its effectiveness in chronic disease is hindered by the length of time needed to demonstrate negative serological conversion. We manually reviewed long-term follow-up data from hospital records of patients with chronic Chagas disease (N = 1,497) in Argentina diagnosed during 1967-1980. All patients were aged ≥18 years at diagnosis and were either treated with nifurtimox (n = 968) or received no antitrypanosomal treatment (n = 529). The primary endpoint was negative seroconversion (the "event"), defined as a change from positive to negative in the serological or parasitological laboratory test used at diagnosis. Time to event was from baseline visit to date of endpoint event or censoring. The effectiveness of nifurtimox versus no treatment was estimated with Cox proportional hazard regression using propensity scores with overlap weights to calculate the hazard ratio and 95% confidence interval. The nifurtimox group was younger than the untreated group (mean, 32.4 vs. 40.3 years), with proportionally fewer females (47.9% vs. 60.1%), and proportionally more of the nifurtimox group than the untreated group had clinical signs and symptoms of Chagas disease at diagnosis (28.9% vs. 14.0%). Median maximum daily dose of nifurtimox was 8.0 mg/kg/day (interquartile range [IQR]: 8.0-9.0) and median treatment duration was 44 days (IQR: 1-90). Median time to event was 2.1 years (IQR: 1.0-4.5) for nifurtimox-treated and 2.4 years (IQR: 1.0-4.2) for untreated patients. Accounting for potential confounders, the estimated hazard ratio (95% confidence interval) for negative seroconversion was 2.22 (1.61-3.07) favoring nifurtimox. Variable treatment regimens and follow-up duration, and an uncommonly high rate of spontaneous negative seroconversion, complicate interpretation of this epidemiological study, but with the longest follow-up and largest cohort analyzed to date it lends weight to the benefit of nifurtimox in adults with chronic Chagas disease. Trial registration: The study protocol was registered at ClinicalTrials.gov: NCT03784391.
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Affiliation(s)
- David Vizcaya
- Bayer Pharmaceuticals, Sant Joan Despi, Spain
- * E-mail:
| | | | | | | | | | - Sandra Seu
- Centro de Chagas y Patología Regional, Hospital Independencia, Santiago del Estero, Argentina
| | - Teresa Ramirez
- Centro de Chagas y Patología Regional, Hospital Independencia, Santiago del Estero, Argentina
| | | | - Oscar Ledesma
- Centro de Chagas y Patología Regional, Hospital Independencia, Santiago del Estero, Argentina
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A Parasite Biomarker Set for Evaluating Benznidazole Treatment Efficacy in Patients with Chronic Asymptomatic Trypanosoma cruzi Infection. Antimicrob Agents Chemother 2019; 63:AAC.02436-18. [PMID: 31358581 DOI: 10.1128/aac.02436-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 07/18/2019] [Indexed: 12/20/2022] Open
Abstract
One of the current greatest challenges of Chagas disease is the establishment of biomarkers to assess the efficacy of drugs in a short period of time. In this context, the reactivity of sera from 66 adults with chronic indeterminate Chagas disease (IND) for a set of four Trypanosoma cruzi antigens (KMP11, PFR2, HSP70, and 3973d) was analyzed before and after benznidazole treatment. The results showed that the reactivity against these antigens decreased at 9, 24, and 48 months after treatment. Moreover, the 42.4% and 68.75% of IND patients met the established standard criteria of therapeutic efficacy (STEC) at 24 and 48 months posttreatment, respectively. Meeting the STEC implied that there was a continuous decrease in the reactivity of the patient sera against the four antigens after treatment and that there was a substantial decrease in the reactivity for at least two of the antigens. This important decrease in reactivity may be associated with a drastic reduction in the parasite load, but it is not necessarily associated with a parasitological cure. After treatment, a positive PCR result was only obtained in patients who did not meet the STEC. The percentage of granzyme B+/perforin+ CD8+ T cells was significantly higher in patients who met the STEC than in those who did not meet the STEC (35.2% versus 2.2%; P < 0.05). Furthermore, the patients who met the STEC exhibited an increased quality of the multifunctional response of the antigen-specific CD8+ T cells compared with that in the patients who did not meet the STEC.
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Moscatelli G, Moroni S, García Bournissen F, González N, Ballering G, Schijman A, Corral R, Bisio M, Freilij H, Altcheh J. Longitudinal follow up of serological response in children treated for Chagas disease. PLoS Negl Trop Dis 2019; 13:e0007668. [PMID: 31465522 PMCID: PMC6715178 DOI: 10.1371/journal.pntd.0007668] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 07/28/2019] [Indexed: 01/05/2023] Open
Abstract
Background Evaluation of therapeutic response in chronic Chagas disease is a major challenge, due to prolonged persistence of Trypanosoma cruzi-specific antibodies, lack of sensitivity of parasitological tests, and need for long-term follow-up to observe negative seroconversion of conventional serological tests (CS). The objective of this study was to evaluate F2/3-ELISA serology, a promising early biomarker of therapeutic response, and T.cruzi Polymerase chain reaction (PCR) for T. cruzi Deoxyribonucleic acid (DNA), for neonatal diagnosis and evaluation of parasitemia after treatment. Methods Prospective cohort study, with three-year clinical, serological and parasitological follow-up of pediatric Chagas disease patients treated with benznidazole. Serology was evaluated by Enzyme-Linked ImmunoSorbent Assay (ELISA), Indirect hemagglutination (IHA) and F2/3-ELISA; Parasitemia by microhematocrit (MH) and PCR. Results A cohort of 107 pediatric patients treated with benznidazole was enrolled in the study. ELISA and IHA were initially reactive in 100% of patients, F2/3-ELISA serology was reactive in 80% (86/107) and 91% (97/107) had detectable parasitemia. Seventy-six (71%) patients completed at least 36 months of serological follow up after treatment. Although a similar decreasing linear trend was observed for all serological tests, F2/3-ELISA presented earlier, age dependent, negative seroconversion compared to CS. All patients reaching undetectable CS titers had previously seroreverted by F2/3-ELISA. All patients with persistently decreasing antibody titers had negative PCRs throughout the follow up period. No new cardiological lesions were observed during the 3 years follow-up period. Conclusions The data reported here, using CS, F2/3 ELISA and PCR provide support for the efficacy of benznidazole in congenital Chagas diseases. These results provide support for scaling up of screening, diagnosis and access to benznidazole treatment. Trial registration ClinicalTrials.gov 0028/04 in the Research Council, Secretary of Health Buenos Aires city Goberment. Evaluation of therapeutic response in chronic Chagas disease is a major challenge, particularly in the early post-treatment phase, due to prolonged persistence of Trypanosoma cruzi-specific antibodies and lack of sensitivity of available parasitological tests. The main limitation in evaluating Chagas disease treatment response stems from the need for long-term follow-up to observe negative seroconversion of conventional serological tests. New biomarkers of cure are needed. We evaluated F2/3-ELISA, a promising early serological marker of therapeutic response, and T.cruzi PCR for T.cruzi DNA, for neonatal diagnosis and evaluation of parasitemia after treatment. F2/3-ELISA and PCR proved to be excellent early markers of treatment response that correlate with ELISA and IHA but can identify treatment response or failure at much earlier timepoints. This information can help design future paediatric clinical trials in Chagas disease.
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Affiliation(s)
- Guillermo Moscatelli
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
- Multidisciplinary Institute for Research of Pediatric Diseases- CONICET-GCBA, Buenos Aires, Argentina
- * E-mail:
| | - Samanta Moroni
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
- Multidisciplinary Institute for Research of Pediatric Diseases- CONICET-GCBA, Buenos Aires, Argentina
| | - Facundo García Bournissen
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
- Multidisciplinary Institute for Research of Pediatric Diseases- CONICET-GCBA, Buenos Aires, Argentina
| | - Nicolás González
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
| | - Griselda Ballering
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
| | - Alejandro Schijman
- Molecular Biology Laboratory of Chagas disease, INGEBI-CONICET, Buenos Aires, Argentina
| | - Ricardo Corral
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
| | - Margarita Bisio
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
| | - Héctor Freilij
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
| | - Jaime Altcheh
- Parasitology service Ricardo Gutiérrez Children´s Hospital, Buenos Aires, Argentina
- Multidisciplinary Institute for Research of Pediatric Diseases- CONICET-GCBA, Buenos Aires, Argentina
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The Trypomastigote Small Surface Antigen from Trypanosoma cruzi Improves Treatment Evaluation and Diagnosis in Pediatric Chagas Disease. J Clin Microbiol 2017; 55:3444-3453. [PMID: 28978686 DOI: 10.1128/jcm.01317-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 09/27/2017] [Indexed: 02/06/2023] Open
Abstract
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi Assessment of parasitological cure upon treatment with available drugs relies on achieving consistent negative results in conventional parasitological and serological tests, which may take years to assess. Here, we evaluated the use of a recombinant T. cruzi antigen termed trypomastigote small surface antigen (TSSA) as an early serological marker of drug efficacy in T. cruzi-infected children. A cohort of 78 pediatric patients born to T. cruzi-infected mothers was included in this study. Only 39 of the children were infected with T. cruzi, and they were immediately treated with trypanocidal drugs. Serological responses against TSSA were evaluated in infected and noninfected populations during the follow-up period using an in-house enzyme-linked immunosorbent assay (ELISA) and compared to conventional serological methods. Anti-TSSA antibody titers decreased significantly faster than anti-whole parasite antibodies detected by conventional serology both in T. cruzi-infected patients undergoing effective treatment and in those not infected. The differential kinetics allowed a significant reduction in the required follow-up periods to evaluate therapeutic responses or to rule out maternal-fetal transmission. Finally, we present the case of a congenitally infected patient with an atypical course in whom TSSA provided an early marker for T. cruzi infection. In conclusion, we showed that TSSA was efficacious both for rapid assessment of treatment efficiency and for early negative diagnosis in infants at risk of congenital T. cruzi infection. Based upon these findings we propose the inclusion of TSSA for refining the posttherapeutic cure criterion and other diagnostic needs in pediatric Chagas disease.
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Goulart LR, da S. Ribeiro V, Costa-Cruz JM. Anti-parasitic Antibodies from Phage Display. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1053:155-171. [DOI: 10.1007/978-3-319-72077-7_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Balouz V, Agüero F, Buscaglia CA. Chagas Disease Diagnostic Applications: Present Knowledge and Future Steps. ADVANCES IN PARASITOLOGY 2016; 97:1-45. [PMID: 28325368 PMCID: PMC5363286 DOI: 10.1016/bs.apar.2016.10.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chagas disease, caused by the protozoan Trypanosoma cruzi, is a lifelong and debilitating illness of major significance throughout Latin America and an emergent threat to global public health. Being a neglected disease, the vast majority of Chagasic patients have limited access to proper diagnosis and treatment, and there is only a marginal investment into R&D for drug and vaccine development. In this context, identification of novel biomarkers able to transcend the current limits of diagnostic methods surfaces as a main priority in Chagas disease applied research. The expectation is that these novel biomarkers will provide reliable, reproducible and accurate results irrespective of the genetic background, infecting parasite strain, stage of disease, and clinical-associated features of Chagasic populations. In addition, they should be able to address other still unmet diagnostic needs, including early detection of congenital T. cruzi transmission, rapid assessment of treatment efficiency or failure, indication/prediction of disease progression and direct parasite typification in clinical samples. The lack of access of poor and neglected populations to essential diagnostics also stresses the necessity of developing new methods operational in point-of-care settings. In summary, emergent diagnostic tests integrating these novel and tailored tools should provide a significant impact on the effectiveness of current intervention schemes and on the clinical management of Chagasic patients. In this chapter, we discuss the present knowledge and possible future steps in Chagas disease diagnostic applications, as well as the opportunity provided by recent advances in high-throughput methods for biomarker discovery.
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Affiliation(s)
- Virginia Balouz
- Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, B 1650 HMP, Buenos Aires, Argentina
| | - Fernán Agüero
- Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, B 1650 HMP, Buenos Aires, Argentina
| | - Carlos A. Buscaglia
- Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, B 1650 HMP, Buenos Aires, Argentina
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Apt W, Arribada A, Zulantay I, Solari A, Sánchez G, Mundaca K, Coronado X, Rodríguez J, Gil LC, Osuna A. Itraconazole or allopurinol in the treatment of chronic American trypanosomiasis: the results of clinical and parasitological examinations 11 years post-treatment. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 99:733-41. [PMID: 16297286 DOI: 10.1179/136485905x75403] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Eleven years after they had been given itraconazole or allopurinol for the treatment of chronic American trypanosomiasis, 109 adult patients were checked for electrocardiographic abnormalities and evidence of Trypanosoma cruzi infection. The parasitological investigations included xenodiagnosis, in which the faeces of Triatoma infestans that had fed on the patients were checked under the microscope for flagellates. In addition, a PCR-based assay and a hybridization assay were used to test blood samples from the patients, and faeces from the Tri. infestans that had fed on the patients, for Try. cruzi DNA. For the data analysis, the patients were divided into four groups known as normal/normal, abnormal/normal, normal/abnormal and abnormal/abnormal, according to whether the patients had been found to have normal or abnormal electrocardiograms (ECG) shortly before the first treatment and to have normal or abnormal ECG when checked at the 11-year follow-up. The 51 normal/normal and 24 normal/abnormal patients were assumed to have been in the 'indeterminate' phase of the disease when they were treated, whereas the 16 abnormal/normal and 18 abnormal/abnormal patients all had evidence of chagasic cardiopathy at that time. When checked 11 years post-treatment, 40 (78.4%), 17 (70.8%), 14 (87.5%) and 17 (94.4%) of these patients, respectively, were each found positive for Try. cruzi in at least one of the parasitological tests. The hybridization assay, whether applied to human blood or bug faeces, appeared a significantly more sensitive test than the PCR-based assays or microscopically assessed xenodiagnosis (P<0.05). Only the 21 patients who appeared to be negative for Try. cruzi could be considered parasitologically cured (although all still appeared to have anti-Try. cruzi antibodies in their blood). Only 13 of these parasitologically cured patients (seven of those treated with itraconazole and six of those given allopurinol) had normal ECG at the 11-year follow-up. In Chile at least, itraconazole, which caused fewer adverse effects than the allopurinol while being no less effective at preventing cardiopathy, appears to be the drug of choice to treat chronic American trypanosomiasis in adults.
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Affiliation(s)
- W Apt
- Laboratorio de Parasitología Básico-Clínico, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, P.O. Box 427, Santiago 3, Chile.
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Use of an enzyme-linked immunosorbent assay that utilizes the Tc13Tul antigen of Trypanosoma cruzi to monitor patients after treatment with benznidazole. Diagn Microbiol Infect Dis 2013; 76:197-205. [DOI: 10.1016/j.diagmicrobio.2013.02.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/19/2013] [Accepted: 02/07/2013] [Indexed: 11/22/2022]
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Machado-de-Assis GF, Silva AR, Do Bem VAL, Bahia MT, Martins-Filho OA, Dias JCP, Albajar-Viñas P, Torres RM, Lana M. Posttherapeutic cure criteria in Chagas' disease: conventional serology followed by supplementary serological, parasitological, and molecular tests. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1283-91. [PMID: 22739694 PMCID: PMC3416099 DOI: 10.1128/cvi.00274-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/15/2012] [Indexed: 11/20/2022]
Abstract
We performed a critical study of conventional serology, followed by supplementary serological, parasitological, and molecular tests, to assess the response to etiologic treatment of Chagas' disease. A group of 94 Chagas' disease patients treated with benznidazole at least 10 years earlier were evaluated from the laboratory and clinical points of view. When conventional serology (enzyme-linked immunosorbent assay [ELISA], indirect immunofluorescence [IIF], and indirect hemagglutination [IHA]) and classic criteria (consistent results with any two of the three tests) or more rigorous criteria (consistent results from the three tests) were used, 10.6% and 8.5% of patients were considered treated and cured (TC) by classic and rigorous criteria, respectively. Patients were then evaluated using supplementary (recombinant ELISA and Trypanosoma cruzi excreted-secreted antigen blotting [TESA-blot]), parasitological (hemoculture), and molecular (PCR) tests. The results of recombinant ELISA were similar to those with the rigorous criterion (three consistent test results). The TESA-blot group showed a higher percentage (21.3%) of negative results than the groups defined by either cure criterion. Hemoculture and PCR gave negative results for all treated and cured (TC) patients, regardless of the criterion used. Recombinant ELISA and TESA-blot tests showed negative results for 70% and 87.5% of the patients categorized as TC by the classic and three-test criteria, respectively. For patients with discordant conventional serology, the supplementary serological and molecular tests were the decisive factor in determining therapeutic failure. Clinical evaluation showed that 62.5% of TC patients presented with the indeterminate form of the disease. Additionally, treated patients with negative TESA-blot results should be reevaluated later with all methodologies used here to verify whether TESA-blot is a reliable way to determine early parasitological cure of Chagas' disease.
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Affiliation(s)
- G F Machado-de-Assis
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP), Ouro Preto, Brazil.
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Therapy of chagas disease: implications for levels of prevention. J Trop Med 2012; 2012:292138. [PMID: 22523499 PMCID: PMC3317183 DOI: 10.1155/2012/292138] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 11/26/2011] [Accepted: 11/26/2011] [Indexed: 11/29/2022] Open
Abstract
This paper reviews the evidence supporting the use of etiological treatment for Chagas disease that has changed the standard of care for patients with Trypanosoma cruzi infection in the last decades. Implications of this evidence on different levels of prevention as well as gaps in current knowledge are also discussed. In this regard, etiological treatment has shown to be beneficial as an intervention for secondary prevention to successfully cure the infection or to delay, reduce, or prevent the progression to disease, and as primary disease prevention by breaking the chain of transmission. Timely diagnosis during initial stages would allow for the prescription of appropriate therapies mainly in the primary health care system thus improving chances for a better quality of life. Based on current evidence, etiological treatment has to be considered as an essential public health strategy useful to reduce disease burden and to eliminate Chagas disease altogether.
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Gomes YM, Lorena VMB, Luquetti AO. Diagnosis of Chagas disease: what has been achieved? What remains to be done with regard to diagnosis and follow up studies? Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:115-21. [PMID: 19753466 DOI: 10.1590/s0074-02762009000900017] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 06/03/2009] [Indexed: 11/22/2022] Open
Abstract
In the acute phase and in the chronic forms of Chagas disease, the etiological diagnosis may be performed by detection of the parasite using direct or indirect parasitological methods and by the presence of antibodies in the serum by way of serological tests. Several techniques are easily available, ranging from the simplest wet smear preparation to immuno-enzymatic assays with recombinant antigens that will meet most diagnostic needs. Other tests under evaluation include a molecular test using polymerase chain reaction, which has shown promising results and may be used as a confirmatory test both in the acute and chronic phases of the disease. Better rapid tests are needed for diagnosis, some of which are already under evaluation. Additionally, there is a need for tools that can identify patients cured shortly after specific treatment. Other needs include a marker for prognosis and early diagnosis of congenital transmission.
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Affiliation(s)
- Yara M Gomes
- Laboratório de Imunoparasitologia, Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães-Fiocruz, Recife, PE, Brasil.
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Chippaux JP, Clavijo ANS, Santalla JA, Postigo JR, Schneider D, Brutus L. Antibody drop in newborns congenitally infected by Trypanosoma cruzi treated with benznidazole. Trop Med Int Health 2009; 15:87-93. [PMID: 19968839 DOI: 10.1111/j.1365-3156.2009.02431.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To compare the drop of Chagas antibody titres between non-infected and congenitally infected newborns treated by two doses of benznidazole, aiming at evaluating the recovery time and giving recommendations regarding serological criteria of recovery. METHODS During a clinical trial, the drop of Trypanosoma cruzi antibody titres measured by ELISA tests was followed during the first year of life in congenitally infected newborns treated with different doses of benznidazole and compared to T. cruzi antibody titres in non-parasitaemic newborns. Confirmation of recovery was given by two negative serological tests: Chagas Stat-Pak (CSP) (immunochromatography) and Chagatest v3.0 (ELISA). RESULTS In non-parasitaemic infants of infected mothers, antibodies of maternal origin disappeared in <8 months while in infected infants, T. cruzi antibodies decreased more slowly and disappeared in 9-16 months allowing to confirm the recovery. All CSP tests were negative before the ninth month while about 10% of ELISA tests remained positive at the 12th month. CONCLUSIONS Recovery may be confirmed in most cases at 10 months. The CSP test was compared to Chagatest v3.0 ELISA and appeared to give a reliable response. The decrease rate of antibodies does not depend on treatment modes.
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Affiliation(s)
- Jean-Philippe Chippaux
- IRD UR010, Team Mother's and Child's Health in Tropical Environment, Institut de Recherche pour le Développement, La Paz, Bolivia.
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Krettli AU. The utility of anti-trypomastigote lytic antibodies for determining cure of Trypanosoma cruzi infections in treated patients: an overview and perspectives. Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:142-51. [DOI: 10.1590/s0074-02762009000900020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 06/09/2009] [Indexed: 11/22/2022] Open
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Silva AG, Silveira-Lacerda EP, Cunha-Júnior JP, de Souza MA, Favoreto Junior S. Immunoblotting analyses using two-dimensional gel electrophoresis of Trypanosoma cruzi excreted-secreted antigens. Rev Soc Bras Med Trop 2005; 37:454-9. [PMID: 15765593 DOI: 10.1590/s0037-86822004000600005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Trypanosoma cruzi trypomastigotes excrete-secrete a complex mixture of antigenic molecules. This antigenic mixture denominated trypomastigote excreted-secreted antigens contains a 150-160 kDa band that shows excellent performance in Chagas' disease diagnosis by immunoblotting. The present study partially characterized by two-dimensional gel electrophoresis the immunoreactivity against the 150-160 kDa protein using sera samples from chagasic patients in different phases of the disease. Trypomastigote excreted-secreted antigen preparations were subjected to high-resolution two-dimensional (2D) gel electrophoresis followed by immunoblotting with sera from chagasic and non-chagasic patients. The 150-160 kDa protein presented four isoforms with isoelectric focusing ranging from 6.2 to 6.7. The four isoforms were recognized by IgM from acute phase and IgG from chronic phase sera of chagasic patients. The 150-160 kDa isoform with IF of approximately 6.4 became the immunodominant spot with the progression of the disease. No cross-reactivity was observed with non-chagasic or patients infected with Leishmania sp. In this study we provide basic knowledge that supports the validation of trypomastigote excreted-secreted antigens for serological diagnosis of Chagas' disease.
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Affiliation(s)
- Adriano Gomes Silva
- Laboratório de Imunologia do Instituto de Ciências Biomédicas da Universidade Federal de Uberlândia, Uberlândia, MG, Brasil
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Silva ED, Pereira VR, Gomes JA, Lorena VMB, Cançado JR, Ferreira AG, Krieger MA, Goldenberg S, Correa‐Oliveira R, Gomes YM. Use of the EIE-recombinant-Chagas-biomanguinhos kit to monitor cure of human Chagas' disease. J Clin Lab Anal 2002; 16:132-6. [PMID: 11968049 PMCID: PMC6807848 DOI: 10.1002/jcla.10028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We used the EIE-Recombinant-Chagas-Biomanguinhos kit (EIE-Rec kit) developed by the Oswaldo Cruz Foundation, Brazil, to monitor cure of chagasic patients who were treated during the acute phase of T. cruzi infection. Treated patients were previously studied by parasitological and serological tests and classified as cured patients (CP) (n = 10), dissociated patients (DP) (n = 6), and noncured patients (NCP) (n = 6). When sera of these patients were assayed by EIE-Rec kit all sera from NCP and all sera from CP showed positive and negative reactions, respectively. These results were in full agreement with those obtained previously by the classical tests. Two DP showed a positive reaction; the remaining four displayed a negative reaction, similar to that observed in sera from nonchagasic (NCh) individuals, and could therefore be considered CP. Our results suggest that the EIE-Rec kit could be used to monitor the efficacy of Chagas' disease treatment.
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Affiliation(s)
| | | | | | | | - Joaquim R. Cançado
- Faculdade de Medicina, Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Marco Aurélio Krieger
- Instituto Oswaldo Cruz/Fiocruz, Rio de Janeiro, RJ, Brazil
- Instituto de Biologia Molecular do Paraná, Curitiba, PR, Brazil
| | - Samuel Goldenberg
- Instituto Oswaldo Cruz/Fiocruz, Rio de Janeiro, RJ, Brazil
- Instituto de Biologia Molecular do Paraná, Curitiba, PR, Brazil
| | | | - Yara M. Gomes
- Centro de Pesquisas Aggeu Magalhães/Fiocruz, Recife, PE, Brazil
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16
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CANÇADO JR. Long term evaluation of etiological treatment of Chagas disease with benznidazole. Rev Inst Med Trop Sao Paulo 2002. [DOI: 10.1590/s0036-46652002000100006] [Citation(s) in RCA: 228] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this article is to present an investigation of cure rate, after long follow up, of specific chemotherapy with benznidazole in patients with both acute and chronic Chagas disease, applying quantitative conventional serological tests as the base of the criterion of cure. Twenty one patients with the acute form and 113 with one or other of the various chronic clinical forms of the disease were evaluated, after a follow up period of 13 to 21 years, for the acute, and 6 to 18 years, for the chronic patients. The duration of the acute as well as the chronic disease, a condition which influences the results of the treatment, was determined. The therapeutic schedule was presented, with emphasis on the correlation between adverse reactions and the total dose of 18 grams, approximately, as well as taking into consideration precautions to assure the safety of the treatment. Quantitative serological reactions consisting of complement fixation, indirect immunofluorescence, indirect hemagglutination, and, occasionally, ELISA, were used. Cure was found in 76 per cent of the acute patients but only in 8 per cent of those with chronic forms of the disease. In the light of such contrasting results, fundamentals of the etiological therapy of Chagas disease were discussed, like the criterion of cure, the pathogenesis and the role of immunosuppression showing tissue parasitism in long standing chronic disease, in support of the concept that post-therapeutic consistently positive serological reactions mean the presence of the parasite in the patient's tissues. In relation to the life-cycle of T. cruzi in vertebrate host, there are still some obscure and controversial points, though there is no proof of the existence of resistant or latent forms. However, the finding over the last 15 years, that immunosuppression brings about the reappearance of acute disease in long stand chronic patients justifies a revision of the matter. Facts were quoted in favor of the treatment of chronic patients.
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Affiliation(s)
- J. Romeu CANÇADO
- Universidade Federal de Minas Gerais, Brasil; Universidade Federal de Minas Gerais
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17
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Umezawa ES, Nascimento MS, Stolf AM. Enzyme-linked immunosorbent assay with Trypanosoma cruzi excreted-secreted antigens (TESA-ELISA) for serodiagnosis of acute and chronic Chagas' disease. Diagn Microbiol Infect Dis 2001; 39:169-76. [PMID: 11337184 DOI: 10.1016/s0732-8893(01)00216-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the present report we describe the use of Trypomastigote Excreted-Secreted Antigens (TESA) as antigen in ELISA for Chagas' disease serodiagnosis. The study was carried out on 284 patients, 164 of whom were nonchagasic subjects including individuals with leishmaniasis or other pathologies, and 120 chagasic patients, being 53 in the acute (with positive IgA and IgM antibodies to T. cruzi) and 67 in the chronic phase. TESA-ELISA showed 100% positivity in the survey of IgG antibodies in chagasic patients (acute and chronic) and 100% positivity for IgM antibodies in acute phase sera. TESA preparation does not require biochemical purification procedures and does not present the cross-reactivity of leishmaniasis sera observed when ELISA with epimastigote alkaline extract (EAE) is performed. ELISA competition assays showed that anti-T. cruzi antibodies of sera from chagasic patients that react with TESA are different from those that react with EAE. Besides, partial characterization of TESA showed that several epitopes present in this fraction are absent in EAE.
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Affiliation(s)
- E S Umezawa
- Instituto de Medicina Tropical de São Paulo da Faculdade de Medicina da Universidade de São Paulo, laboratório de Protozoologia Av. Dr. Enéas de Carvalho Aguiar 470, CEP 05403-000, São Paulo, Brazil.
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18
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Sosa Estani S, Segura EL. Treatment of Trypanosoma cruzi infection in the undetermined phase. Experience and current guidelines of treatment in Argentina. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:363-5. [PMID: 10677756 DOI: 10.1590/s0074-02761999000700070] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- S Sosa Estani
- Centro Nacional de Diagnóstico e Investigación de Endemoepidemias, Buenos Aires, Argentina
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19
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Krettli A. Diagnosis of Trypanosoma cruzi chronic infections in humans: usefulness of the complement regulatory protein antigens and lytic antibodies in the control of cure. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:301-4. [PMID: 10677741 DOI: 10.1590/s0074-02761999000700055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- A Krettli
- Centro de Pesquisas René Rachou, Fiocruz, Belo Horizonte, MG, 30190-002, Brasil.
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20
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Gontijo ED, Galvão LM, Eloi-Santos S. Chagas disease: criteria of cure and prognosis. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:357-62. [PMID: 10677755 DOI: 10.1590/s0074-02761999000700069] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- E D Gontijo
- Departamento de Medicina Preventiva e Social, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 30130-100, Brasil.
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21
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Fabbro De Suasnábar D, Arias E, Streiger M, Piacenza M, Ingaramo M, Del Barco M, Amicone N. Evolutive behavior towards cardiomyopathy of treated (nifurtimox or benznidazole) and untreated chronic chagasic patients. Rev Inst Med Trop Sao Paulo 2000; 42:99-109. [PMID: 10810325 DOI: 10.1590/s0036-46652000000200007] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aim of this work was to compare the evolution of chronic chagasic untreated patients (UTPs) with that of benznidazole or nifurtimox-treated patients (TPs). A longitudinal study from a low endemic area (Santa Fe city, Argentina) was performed during an average period of 14 years. Serological and parasitological analyses with clinical exams, ECG and X-chest ray were carried out. At the onset, 19/198 infected patients showed chagasic cardiomyopathy (CrChM) while 179 were asymptomatic. In this latter group the frequency of CrChM during the follow-up was lower in TPs compared with UTPs (3.2% vs 7%). Within the CrChM group, 2/5 TPs showed aggravated myopathy whereas this happened in 9/14 UTPs. Comparing the clinical evolution of all patients, 5.9% of TPs and 13% of UTPs had unfavourable evolution, but the difference is not statistically relevant. Serological titers were assessed by IIF. Titers equal to or lower than 1/64 were obtained in 86% of the TPs, but only in 38% of UTPs. The differences were statistically significant (geometric mean: 49.36 vs. 98.2). Antiparasitic assessment of the drugs (xenodiagnosis) proved to be effective. The low sensitivity in chronic chagasic patients must be born in mind. Despite treated patients showed a better clinical evolution and lower antibody levels than untreated ones, it is necessary to carry on doing research in order to improve therapeutic guidelines, according to the risk/benefit equation and based on scientific and ethical principles.
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Affiliation(s)
- D Fabbro De Suasnábar
- Centro de Investigaciones sobre Endemias Nacionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
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22
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Engel JC, Doyle PS, Palmer J, Hsieh I, Bainton DF, McKerrow JH. Cysteine protease inhibitors alter Golgi complex ultrastructure and function in Trypanosoma cruzi. J Cell Sci 1998; 111 ( Pt 5):597-606. [PMID: 9454733 DOI: 10.1242/jcs.111.5.597] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cruzain, the major cysteine protease of the protozoan parasite Trypanosoma cruzi, is a target of rational drug design for chemotherapy of Chagas' disease. The precise biological role of cruzain in the parasite life cycle and the mechanism involved in the trypanocidal effect of cysteine protease inhibitors are still unclear. Here we report biological and ultrastructural alterations caused by cysteine protease inhibitors in T. cruzi epimastigotes. Cruzain, a glycoprotein that transits the Golgi-endosomal pathway, localized to pre-lysosomes/lysosomes in the posterior end of untreated epimastigotes by fluorescent microscopy utilizing either a biotinylated cysteine protease inhibitor to tag the active site, or a specific anti-cruzain antibody. Radiolabeled or biotinylated cysteine protease inhibitors bound exclusively to cruzain in intact epimastigotes confirming that cruzain is accessible to, and is targeted by the inhibitors. Treatment of T. cruzi epimastigotes with specific cysteine protease inhibitors arrested growth, altered the intracellular localization of cruzain, and induced major alterations in the Golgi complex. Following treatment, cruzain accumulated in peripheral dilations of Golgi cisternae. There was a concomitant 70% reduction in gold-labeled cruzain transported to lysosomes. Cisternae abnormalities in the Golgi compartment were followed by distention of ER and nuclear membranes. Brefeldin A increased the number and size of cisternae in epimastigotes. Pre-treatment of epimastigotes with cysteine protease inhibitors followed by exposure to brefeldin A induced a more rapid appearance of the cysteine protease inhibitor-induced Golgi alterations. Our results suggest that cysteine protease inhibitors prevent the normal autocatalytic processing and trafficking of cruzain within the Golgi apparatus. Accumulation of cruzain may decrease mobility of Golgi membranes and result in peripheral distention of cisternae. These major alterations of the Golgi complex parallel the death of T. cruzi epimastigotes.
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Affiliation(s)
- J C Engel
- Department of Pathology, University of California, San Francisco, California 94143, USA.
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23
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Yokoyama-Yasunaka JKU, Piazza RMF, Umezawa ES, Stolf AMS. Reactivity of chagasic antigal antibodies with noninfected cells treated withTrypanosoma cruzi secreted/excreted antigens. J Clin Lab Anal 1998. [DOI: 10.1002/(sici)1098-2825(1998)12:2<108::aid-jcla6>3.0.co;2-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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24
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de Andrade AL, Zicker F, de Oliveira RM, Almeida Silva S, Luquetti A, Travassos LR, Almeida IC, de Andrade SS, de Andrade JG, Martelli CM. Randomised trial of efficacy of benznidazole in treatment of early Trypanosoma cruzi infection. Lancet 1996; 348:1407-13. [PMID: 8937280 DOI: 10.1016/s0140-6736(96)04128-1] [Citation(s) in RCA: 330] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Benznidazole, a nitroimidazole derivative, has been recommended for the treatment of acute and congenital Trypanosoma cruzi infection (Chagas' disease). We have examined the safety and efficacy of this drug in the treatment of the early chronic phase of T cruzi infection. METHODS Between 1991 and 1995, we carried out a randomised, double-blind, placebo-controlled trial in a rural area of Brazil with endemic Chagas' disease. 82% of 2434 schoolchildren (aged 7-12 years) identified in a census were screened for antibodies to T cruzi by indirect immunofluorescence, indirect haemagglutination, and ELISA. 130 were positive in all tests and were randomly assigned benznidazole (7.5 mg/kg daily for 60 days by mouth) or placebo. The primary endpoint for efficacy was the disappearance of specific antibodies (negative seroconversion) by the end of 3-year follow-up. The secondary endpoint was the reduction of antibody titres on repeated serological tests. One child moved away from the area just after randomisation and was excluded from the analyses. Insecticidal measures were taken throughout the trial to reduce the risk of reinfection. FINDINGS Minor side-effects requiring no specific medication were recorded in a small proportion of individuals. On a chemiluminescent ELISA with purified trypomastigote glycoconjugate, serum from all participants was positive at the beginning of the trial. At the end of follow-up, 37 (58%) of the 64 benznidazole-treated participants and 3 (5%) of those who received placebo were negative for T cruzi antibodies. The efficacy of benznidazole treatment estimated by intention to treat was 55.8% (95% CI 40.8-67.0). At the end of follow-up, children who received benznidazole had five-fold lower geometric mean titres by indirect immunofluorescence than placebo-treated children (196[147-256] vs 1068[809-1408], p < 0.00001). INTERPRETATION The trial showed that a 60-day course of benznidazole treatment of early chronic T cruzi infection was safe and 55.8% effective in producing negative seroconversion of specific antibodies. The results are very encouraging and justify the recommendation of treatment for seropositive children as public health policy.
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Affiliation(s)
- A L de Andrade
- Department of Community Health, Universidade Federal de Golás, Goiânia, Brazil
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25
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26
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Krautz GM, Galvão LM, Cançado JR, Guevara-Espinoza A, Ouaissi A, Krettli AU. Use of a 24-kilodalton Trypanosoma cruzi recombinant protein to monitor cure of human Chagas' disease. J Clin Microbiol 1995; 33:2086-90. [PMID: 7559953 PMCID: PMC228340 DOI: 10.1128/jcm.33.8.2086-2090.1995] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A 24-kDa recombinant protein from Trypanosoma cruzi (rTc24) was evaluated by enzyme-linked immunosorbent assay (ELISA) and Western blot (immunoblot) tests to identify treated chagasic patients considered parasitologically cured on the basis of persistently negative tests of hemocultures and lytic antibodies. Some of these patients were termed dissociated because their sera, although negative by the complement-mediated lysis test, were positive by conventional serology. The negative lysis test indicates the absence of active infection after specific treatment, but this assay requires live and infectious parasites and cannot be used easily in a laboratory routine. Here we tested rTc24 by ELISA and Western blotting as an alternative for the complement-mediated lysis test. For the group of patients with active infection despite the treatment (uncured patients), all the sera tested recognized rTc24 in both tests. For the dissociated patients, approximately 80% of the sera did not react with rTc24 in the ELISA or in Western blots, in agreement with the negative complement-mediated lysis tests. Thus, the 24-kDa T. cruzi recombinant antigen, when used for initial trials to evaluate cure of chagasic patients submitted to specific treatment, will allow the identification of most, but not all, cases.
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Affiliation(s)
- G M Krautz
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Brazil
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27
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Sánchez G, Zulantay I, Venegas J, Solari A, Gálvez R, Peña P, Rodríguez J, Apt W. Treatment with allopurinol and itraconazole changes lytic activity in patients with chronic, low grade Trypanosoma cruzi infection. Trans R Soc Trop Med Hyg 1995; 89:438-9. [PMID: 7570892 DOI: 10.1016/0035-9203(95)90046-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- G Sánchez
- Department of Biochemistry, Faculty of Medicine, University of Chile, Santiago, Chile
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28
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Britto C, Cardoso MA, Vanni CM, Hasslocher-Moreno A, Xavier SS, Oelemann W, Santoro A, Pirmez C, Morel CM, Wincker P. Polymerase chain reaction detection of Trypanosoma cruzi in human blood samples as a tool for diagnosis and treatment evaluation. Parasitology 1995; 110 ( Pt 3):241-7. [PMID: 7724232 DOI: 10.1017/s0031182000080823] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Trypanosoma cruzi specific sequences were amplified by the polymerase chain reaction from total blood of human chagasic patients and normal individuals. A 330 bp fragment originating from kinetoplast DNA was specifically detected in most chagasic individuals. We tested the sensitivity and specificity of this method in normal and affected individuals attending the Evandro Chagas Hospital, Rio de Janeiro. The results of these tests were compared with serological diagnosis performed using standard techniques, and in some cases with xenodiagnosis. We found that none of the serologically negative individuals gave any specific amplification product, whereas 55 out of 61 patients previously serodiagnosed as chagasic were positive using the PCR method (sensitivity: 90%). Xenodiagnosis, which is currently considered to be the most sensitive parasitological technique for Chagas' disease diagnosis, detected only 12 out of 28 serologically positive patients (sensitivity: 43%). The usefulness of the PCR method was further investigated with chagasic patients who had received anti-parasite treatment with benznidazole. It has always been difficult to evaluate the incidence of cure in such cases by serology, since a humoral response against T. cruzi antigens may remain for years even in the absence of the parasite. We observed a positive amplification result in only 9 out of 32 treated patients who remained reactive when tested using classical serology. These observations suggest that PCR is the most sensitive technique available for direct detection of T. cruzi in chagasic patients and that it can be a very useful instrument for the follow-up of patients after specific treatment.
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Affiliation(s)
- C Britto
- Department of Biochemistry and Molecular Biology, Oswaldo Cruz Institute, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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29
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Krautz GM, Coutinho MG, Galvão LM, Cançado JR, Krettli AU. [Soluble antigens released by Trypanosoma cruzi trypomastigotes used in ELISA to detect cure in chagasic patients following specific treatment]. Rev Soc Bras Med Trop 1994; 27:199-207. [PMID: 7531867 DOI: 10.1590/s0037-86821994000400001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Two soluble antigens isolated from T. cruzi were evaluated by ELISA for the diagnosis of chronic infection and assessment of cure after specific chemotherapy, namely, supernatants from parasite cell-cultures (SpAg) and trypomastigote excretory/secretory antigens (ESAg). Among the treated patients, a group defined as "dissociated" had been monitored for 3 to 10 years and displayed negative hemocultures and tests of trypomastigote complement-mediated lysis persistently negative although positive by conventional serology (indirect fluorescence with epimastigote, mainly). A negative lysis test indicates parasite elimination by the patient. Our ELISA results showed that among the non-treated chagasic controls the SpAg e ESAg detected 93% and 100%, of the cases, respectively. However, only 28% of sera from the dissociated group, considered as cured, were positive by ELISA using SpAg whereas all of such sera were negative using ESAg. Therefore ELISA with ESAg seems to be ideal to replace the complement-mediated lysis test with the aim to define cure after treatment of the chronic infection by T. cruzi.
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Affiliation(s)
- G M Krautz
- Centro de Pesquisas René Rachou/Fundação Oswaldo Cruz, Universidade Federal de Minas Gerais, Belo Horizonte, MG
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30
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Yokoyama-Yasunaka JK, Pral EM, Oliveira Júnior OC, Alfieri SC, Stolf AM. Trypanosoma cruzi: identification of proteinases in shed components of trypomastigote forms. Acta Trop 1994; 57:307-15. [PMID: 7810387 DOI: 10.1016/0001-706x(94)90076-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Trypanosoma cruzi trypomastigotes were shown to predominantly release high molecular weight components (above 50 kDa) when allowed to shed for 1 hour in protein-free media. Under these conditions, parasites were not damaged or lysed, as was indicated by: (a) their normal mobility; (b) their retaining of some of the labelled proteins; (c) the unchanged pattern of biotinylated surface proteins after shedding. Shed components were shown to display proteinase activities, detected at 97 and 50/60 kDa in gelatin gels. These proteolytic activities were completely inhibited by E-64, indicating that they were due to cysteine proteinases.
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31
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Norris KA, Galvão LM, Schrimpf JE, Cançado JR, Krettli AU. Humoral immune response to the Trypanosoma cruzi complement regulatory protein as an indicator of parasitologic clearance in human Chagas' disease. Infect Immun 1994; 62:4072-4. [PMID: 8063427 PMCID: PMC303071 DOI: 10.1128/iai.62.9.4072-4074.1994] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Immunoprecipitation of the purified 160-kDa complement regulatory protein of Trypanosoma cruzi by Chagas' disease patient sera was examined as a possible correlate of the complement-mediated lysis test and as an indicator of parasite clearance. The results presented demonstrate that assessment of the humoral response to this antigen is a useful indicator of parasite clearance and may be particularly helpful in the assessment of some patients for whom other serological tests produce ambiguous results.
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Affiliation(s)
- K A Norris
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pennsylvania 15261
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