Chagas' disease: IgA, IgM and IgG antibodies to T. cruzi amastigote, trypomastigote and epimastigote antigens in acute and in different chronic forms of the disease

Abstract

In an attempt to find a better T. cruzi antigen and possible immunological markers for the diagnosis of different clinical forms of Chagas' disease, amastigote and trypomastigote antigens obtained from immunosuppressed mice infected with T. cruzi (Y strain) were assessed in comparison with conventional epimastigote antigens. A total of 506 serum samples from patients with acute and with chronic (indeterminate, cardiac and digestive) forms, from nonchagasic infections, and from healthy individuals were assayed in immunofluorescence (IF) tests, to search for IgG, IgM and IgA antibodies. Amastigote proved to be the most convenient antigen for our purposes, providing higher relative efficiency indexes of 0.946, 0.871 and 0.914 for IgG, IgM and IgA IF tests, respectively. Anti-amastigote antibodies presented higher geometric mean titers (GMT) than anti-trypomastigote and anti-epimastigote. Anti-amastigote IgG antibodies were found in all forms of Chagas' disease, and predominantly IgA antibodies, in chronic digestive and in acute forms, as well as IgM antibodies, in latter forms. Thus, tests with amastigote antigen could be helpful for screening chagasic infections in blood banks. Practical and economical aspects in obtaining amastigotes as here described speak in favour of its use in developing countries, since those from other sources require more complex system of substruction, specialized personnel or equipment.

In-house ELISA method to analyze anti-Trypanosoma cruzi IgG reactivity for differential diagnosis and evaluation of Chagas disease morbidity

“…Higher levels of IgM were predominant in patients presenting the cardiac form, while higher levels of IgA were predominant in those with the digestive form 10 . The predominance of IgA was also verified in patients in the acute phase and in those with the digestive form in the chronic phase 14 , corroborating previous data from this team 15 .…”

“…Patients with chagasic cardiopathy from Virgem da Lapa, the municipality next to Berilo, presented higher total IgG reactivity independent of the use of different serological tests (conventional ELISA, recombinant ELISA, IHA, and indirect immunofluorescence (IIF)) and antigenic preparations 25 . Differently, no association between levels of IgG and clinical manifestations of Chagas disease was observed when 225 patients with different clinical forms of Chagas disease, 121 patients with other diseases (SYP, toxoplasmosis, kalazar, mucocutaneous leishmaniasis, connective tissue diseases, malaria, rubeola, and Pemphigus foliaceus infection), and 160 healthy individuals were evaluated using antigens at different stages of the parasite life cycle (Y strain), and ELISA, IHA, CFR, and IIF techniques 14 . Similarly, no correlation was observed by Cordeiro et al 8 , when they evaluated other groups of chagasic patients from Argentina and State of Minas Gerais, Brazil.…”

Profile of Trypanosoma cruzi Reactivity in a Population at High Risk for Endemic Pemphigus Foliaceus (Fogo Selvagem)

“…However, there was no further information about those PF patients, and relevant data such as geographic location and demographic characteristics of these individuals were not available. 38 The mechanisms involved in anti-Dsg1 autoantibodies formation in patients with Chagas disease remain unknown. One of the possibilities includes compounds of hematophagous insect saliva inducing an immune response against Dsg1.…”

Chagasic enteropathy

“…However, there are only a few publications about the relationship between the involvement of the digestive tube by Chagas' disease and the immune system of the intestine. Specific IgA antibody classes were detected predominantly in patients with the digestive form of the disease (92%) in contrast with 20% of patients with the cardiac form and 21.4% of patients with the indeterminate form 50 . Elevation of serum IgA levels in Chagas' disease was observed only in patients with concomitant dilation of the esophagus and colon while Chagasic patients with the cardiac or indeterminate forms of the disease did not show this abnormality 7 .…”