Association between Trypanosoma cruzi zymodemes and specific humoral depression in chronic chagasic patients

Brenière, Simone Frédérique; Carrasco, Roxana; Antezana, Gerardo; Desjeux, Philippe; Tibayrenc, Michel

doi:10.1016/0035-9203(89)90271-x

Cited by 6 publications

(3 citation statements)

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“…18,19 We believe that the number of reports of these cases is not higher because parasitologic tests are usually not performed in individuals with negative serology. Our results, as well as others reported in the literature, [19][20][21] suggest that conventional serologic tests may be unable to detect infection in some chronic chagasic individuals. This might be due to specific humoral depression in these patients [19][20][21] or the inability of these tests to detect low levels of antibodies to T. cruzi.…”

Section: Resultssupporting

confidence: 80%

“…Our results, as well as others reported in the literature, [19][20][21] suggest that conventional serologic tests may be unable to detect infection in some chronic chagasic individuals. This might be due to specific humoral depression in these patients [19][20][21] or the inability of these tests to detect low levels of antibodies to T. cruzi. In addition to our findings, discordant conventional serologic test results for Chagas' disease diagnosis in blood donor screening have been reported by other researchers.…”

Section: Resultssupporting

confidence: 80%

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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

126

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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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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 80%

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

126

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“…Dos 26 resultados negativos, 24 tinham epidemiologia positiva para doença de Chagas e em 2 deles houve confirmação parasitológica. A ocorrência de xenodiagnóstico positivo em casos com sorologia negativa sugere a possibilidade de inexistência de anticorpos específicos circulantes Brénière et al, 1989).…”

Section: Sorologia Convencional E Diagnóstico De Megaesôfago Chagásicounclassified

Diagnostico molecular de doença de Chagas em pacientes soronegativos portadores de megaesofago

Batista¹,

Costa²

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Background: After 100 years of research, Chagas disease (CD) remains an important public health problem in Latin America. Symptomatic chronic phase is usually characterized by cardiac or digestive commitment and its current diagnosis relies on the measurement of T. cruzi-specific antibodies produced in response to the infection.However, detection of parasite DNA in seronegative persons has been reported.Objectives: Prevalence of CD in a population with esophageal disorders was assessed by conventional serology. We also detected T. cruzi DNA in blood samples of seronegative and inconclusive patients by N-PCR (nested-PCR).Methods and Results: A seroprevalence of 79% for CD in 512 patients with esophageal disorders was determined by ELISA and IIF. Out of 41 blood samples, N-PCR was positive in 31 (76%) cases when serology was negative or inconclusive.Conclusion: As all patients presented suggestive clinical signs of digestive form of CD and most of them were born in endemic areas, we highlight the importance of diagnosis improvement and its implication in blood banks screening. Our data suggest that N-PCR seems to be effective for detection of T. cruzi DNA in patients with inconclusive or negative serology and, eventually, it may be useful to clarify megaesophagus etiology.

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The ‘Exotic’ Systemic Parasitoses: Limited Geographical Distribution; Rarely Encountered in the UK

Cook

1990

Parasitic Disease in Clinical Practice

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Association between Trypanosoma cruzi zymodemes and specific humoral depression in chronic chagasic patients

Cited by 6 publications

References 1 publication

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

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

Diagnostico molecular de doença de Chagas em pacientes soronegativos portadores de megaesofago

The ‘Exotic’ Systemic Parasitoses: Limited Geographical Distribution; Rarely Encountered in the UK

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