The use of peptides for immunodiagnosis of human Chagas disease

Abstract

Chagas disease, caused by the protozoa Trypanosoma cruzi, continues to be a serious public health problem in Latin America, worsened by the limitations in its detection. Given the importance of developing new diagnostic methods for this disease, the present review aimed to verify the number of publications dedicated to research on peptides that demonstrate their usefulness in serodiagnosis. To this end, a bibliographic survey was conducted on the PubMed platform using the keyword "peptide" or "epitope" combined with "Chagas disease" or "Trypanosoma cruzi"; "diagno*" or "serodiagnosis" or "immunodiagnosis", without period restriction. An increasing number of publications on studies employing peptides in ELISA and rapid tests assays was verified, which confirms the expansion of research in this field. It is possible to observe that many of the peptides tested so far originate from proteins widely used in the diagnosis of Chagas, and many of them are part of commercial tests developed. In this sense, as expected, promising results were obtained for several peptides when tested in ELISA, as many of them exhibited sensitivity and specificity values above 90%. Furthermore, some peptides have been tested in several studies, confirming their diagnostic potential. Despite the promising results observed, it is possible to emphasize the need for extensive testing of peptides, using different serological panels, in order to confirm their potential. The importance of producing an effective assay capable of detecting the clinical stages of the disease, as well as new immunogenic antigens that enable new serological diagnostic tools for Chagas disease, is evident.

Keywords: Trypanosoma cruzi; Chagas disease; Imunodiagnosis; peptide; Serodiagnosis.

Fig. 1

Dynamics of parasitemia and sera antibodies, which are the basis for detecting the parasite or its DNA, as well as antibodies, during acute and chronic Trypanosoma cruzi infection. During acute infection, parasitemia is high, allowing for direct examination- and PCR-based diagnosis. Antibody-based methods detecting mostly IgM are also used. Acute phase is the best window for diagnosis for increased treatment efficacy. At the chronic stage, low grade parasitemia does not allow for direct examination, and PCR-based methods are variable in sensitivity. Antibody-based specific IgG serology is widely used. All testes are laboratory-based, with no point-of-care tests currently available. No tests for disease prognosis are currently available