title: Applicability of an optimized non-conventional flow cytometry method to detect anti-Trypanosoma cruzi immunoglobulin G for the serological diagnosis and cure assessment following chemotherapeutic treatment of Chagas disease.
abstract: One of the challenges on immunodiagnostic of Chagas disease in endemic areas has been the search for more practical and safe antigenic preparation that provides tests with higher sensitivity and specificity, with low cross-reactivity. A new approach using fixed Trypanosoma cruzi epimastigotes to detect IgG reactivity was investigated previously. In order to continue this investigation, this study aimed at optimizing the flow cytometry-based method to the diagnosis of Chagas disease patients after specific chemotherapy. To achieve our goal, serum samples from 93 subjects - 52 adults chronically infected by T. cruzi, and 41 uninfected controls were tested by flow cytometry. Secondly, serum samples from patients Treated Cured and Treated Uncured from Chagas disease were also tested to evaluate the potential of the method on assessing cure. After establishing the ideal serum dilution and cut off, 121 serum samples from patients with other endemic infections were tested to check cross-reactivity. The results showed that parasite staining with Evan's blue dye eliminated debris, allowing trustworthy analysis of anti-fixed epimastigote IgG reactivity. The applicability of the method to diagnose Chagas disease was confirmed by the high sensitivity (98.1%) and specificity (100%) found. This method also contributed for post-therapeutic assessment of cure, identifying 94.1% of Treated Uncured and 83.3% of Treated Cured patients. Cross-reactivity was observed in a very low number (6.7%). On the whole, these data highly recommend the use of anti-fixed T. cruzi epimastigote IgG reactivity by flow cytometry to the diagnosis and cure monitoring of Chagas disease in endemic areas.
authors.affiliation: Laboratório de Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ/Minas, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Christiane Santos
authors.initials: CS
authors.lastname: Matos
authors.forename: Jordana Grazziela Alves
authors.initials: JG
authors.lastname: Coelho-Dos-Reis
authors.forename: Anis
authors.initials: A
authors.lastname: Rassi
authors.forename: Alejandro Ostermayer
authors.initials: AO
authors.lastname: Luquetti
authors.forename: João Carlos Pinto
authors.initials: JC
authors.lastname: Dias
authors.forename: Silvana Maria
authors.initials: SM
authors.lastname: Eloi-Santos
authors.forename: Izabelle Teixeira
authors.initials: IT
authors.lastname: Gomes
authors.forename: Danielle Marquete
authors.initials: DM
authors.lastname: Vitelli-Avelar
authors.forename: Ana Paula Barbosa
authors.initials: AP
authors.lastname: Wendling
authors.forename: Roberta Dias Rodrigues
authors.initials: RD
authors.lastname: Rocha
authors.forename: Andréa
authors.initials: A
authors.lastname: Teixeira-Carvalho
authors.forename: Vanessa
authors.initials: V
authors.lastname: Peruhype-Magalhães
authors.forename: Mariléia Chaves
authors.initials: MC
authors.lastname: Andrade
authors.forename: Olindo Assis
authors.initials: OA
authors.lastname: Martins-Filho
mesh_terms: D014355:Chagas Disease / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D016896:Treatment Outcome; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G