Criterion of cure of human Chagas' disease after specific chemotherapy: recent advances

Krettli, Antoniana U.; Cançado, J. R.; Brener, Z.

doi:10.1590/s0074-02761984000500027

Cited by 42 publications

(39 citation statements)

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“…The presence of lytic antibodies has therefore been proposed as an indicator of active ongoing infection and treatment failure , Galvão et al 1993. This test requires the use of live, infectious trypomastigotes and is not practical for routine use in the evaluation of chemotherapeutic agents or in clinical management of chagasic patients (Krettli et al 1984).…”

Section: Usefulness Of Pcr For Establishing Drug Efficacymentioning

confidence: 99%

“…Cure assessment in chronic infections is controversial and difficult to demonstrate, mainly due to the lack of sensitive or specific tests to document parasitological cure (Krettli et al 1984, Galvão et al 1993. However, in the 1990s, assays based on PCR were used to detect T. cruzi DNA in the blood of chronic chagasic patients with an adequate sensitivity (a single parasite cell in 10-20 mL of whole blood) and proven to be a promising tool for evaluating parasitological failure after specific etiologic treatment in chronic infections (Avila et al 1991, Britto et al 1993, 1995, Wincker et al 1994a, b, Junqueira et al 1996, Gomes et al 1999.…”

Section: Treatment Of Chronic Infections -mentioning

confidence: 99%

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Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

Britto¹

2009

Mem. Inst. Oswaldo Cruz

100

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Section: Usefulness Of Pcr For Establishing Drug Efficacymentioning

confidence: 99%

Section: Treatment Of Chronic Infections -mentioning

confidence: 99%

Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

Britto¹

2009

Mem. Inst. Oswaldo Cruz

100

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“…Conventional serologic tests such as the indirect immunofluorescence (IIF) test, the indirect hemagglutination test, and the ELISA are ineffective because they are persistently positive in most treated patients even when parasitologic test results are negative. 8 Since current parasitologic methods have low sensitivity, a negative result does not necessarily mean that the individual is free of infection. Krettli and Brener proposed complement-mediated lysis (CoML), which detects lytic antibodies, as an alternative method.…”

mentioning

confidence: 99%

Chagas' disease diagnosis: comparative analysis of parasitologic, molecular, and serologic methods.

Gomes

Galvao²,

Macedo³

et al. 1999

The American Journal of Tropical Medicine and Hygiene

124

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Abstract. During the course of chronic chagasic infection, low parasitemia levels prevent parasite detection by current techniques such as hemoculture and xenodiagnosis. Since serologic tests have sensitivity but lack specificity, molecular assays based on the polymerase chain reaction (PCR) have been proposed as alternative tools for parasite detection in individuals with chronic Chagas' disease. A variable degree of PCR efficiency has been reported in the literature and illustrates the need for further evaluation of large numbers of chagasic patients. In this study, we compared an optimized PCR technique with hemoculture and complement-mediated lysis (CoML) in 113 individuals from or living in endemic areas of Brazil who had conventional serologic results that were either positive, negative, or inconclusive. The PCR amplification yielded positive results in 83.5% (66 of 79) of individuals with positive serology, 47.6% (10 of 21) with negative serology, and 46.2% (6 of 13) with inconclusive serology. Of 10 patients with negative serology and positive PCR result, eight (80%) had positive CoML, indicating that they could have been chagasic but were not mounting immune responses. The PCR results were also positive for all individuals who had positive hemoculture, for 37 individuals with negative hemoculture and positive serology, and for two of six individuals with inconclusive serology and negative hemoculture. Thirteen individuals living in nonendemic areas who had negative serology were used as a negative control group: 100% had negative PCR results. Our results show that the optimized PCR protocol used here was very sensitive in detecting the presence of Trypanosoma cruzi in chronic chagasic patients. The PCR and CoML results were well correlated in all of the groups studied, which suggests that our PCR protocol may be effective in the evaluation of cure in patients who receive anti-parasite treatment.Different approaches have been used in the diagnosis of chronic Chagas' disease. Serologic tests are used to detect antibodies against Trypanosoma cruzi and not the presence of the parasite itself. These tests have high sensitivity but lack specificity because of antigenic cross-reactivity with parasites such as Leishmania sp. and T. rangeli.1,2 Parasitologic tests such as hemoculture or xenodiagnosis have proven to be highly specific, but the sensitivity of these techniques is low. Recently, molecular assays such as the polymerase chain reaction (PCR), which amplify certain repetitive sequences of trypanosome kinetoplast DNA (kDNA) have been proposed as a good alternative tools for detection of T. cruzi in human blood.3-5 The ഠ330-basepair (bp) fragment of the kinetoplast minicircles is normally used as a target for amplification.The PCR assay has shown a variable degree of efficiency. Initial sensitivity reports ranged from 96% to 100% compared with serologic diagnosis.3,4 A lower sensitivity level was observed by Britto and others 6 and Junqueira and others. 7 These inconsistencies illustrate the need for addi...

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“…Nevertheless, evaluation of treated chagasic patients presents a certain degree of difficulty since CS remain positive for many years post-treatment in a large percentage of patients, including those who have repeatedly negative parasitologic results . CS used to monitor cure (Cançado 1981) slowly and progressively become negative in a small number of treated patients (Krettli et al 1984. Antibodies present in the sera of chagasic patients induce lysis in trypomastigote forms in the presence of a complement (lytic antibodies), indicating the presence of active infection -CoML .…”

mentioning

confidence: 99%

Chagas disease: criteria of cure and prognosis

Gontijo

Galvão

Elói-Santos

1999

Mem. Inst. Oswaldo Cruz

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Criterion of cure of human Chagas' disease after specific chemotherapy: recent advances

Cited by 42 publications

References 0 publications

Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

Chagas' disease diagnosis: comparative analysis of parasitologic, molecular, and serologic methods.

Chagas disease: criteria of cure and prognosis

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