title: Evaluation of the ELISA-F29 test as an early marker of therapeutic efficacy in adults with chronic Chagas disease.
abstract: This work compared the time at which negative seroconversion was detected by conventional serology (CS) and by the ELISA-F29 test on a cohort of chronic chagasic patients treated with nifurtimox or benznidazole. A retrospective study was performed using preserved serum from 66 asymptomatic chagasic adults under clinical supervision, and bi-annual serological examinations over a mean follow-up of 23 years. Twenty nine patients received trypanocide treatment and 37 remained untreated. The ELISA-F29 test used a recombinant antigen which was obtained by expressing the Trypanosoma cruzi flagellar calcium-binding protein gene in Escherichia coli. Among the untreated patients, 36 maintained CS titers. One patient showed a doubtful serology in some check-ups. ELISA-F29 showed constant reactivity in 35 out of 37 patients and was negative for the patient with fluctuating CS. The treated patients were divided into three groups according to the CS titers: in 13 they became negative; in 12 they decreased and in four they remained unchanged. ELISA-F29 was negative for the first two groups. The time at which negativization was detected was significantly lower for the ELISA-F29 test than for CS, 14.5 ± 5.7 and 22 ± 4.9 years respectively. Negative seroconversion was observed in treated patients only. The results obtained confirm that the ELISA-F29 test is useful as an early indicator of negative seroconversion in treated chronic patients.
authors.affiliation: Centro de Investigaciones sobre Endemias Nacionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL), Casilla de Correo 242, Santa Fe, Argentina. dfabbro@fbcb.unl.edu.ar
authors.forename: Diana
authors.initials: D
authors.lastname: Fabbro
authors.forename: Elsa
authors.initials: E
authors.lastname: Velazquez
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Bizai
authors.forename: Susana
authors.initials: S
authors.lastname: Denner
authors.forename: Verónica
authors.initials: V
authors.lastname: Olivera
authors.forename: Enrique
authors.initials: E
authors.lastname: Arias
authors.forename: Carlos
authors.initials: C
authors.lastname: Pravia
authors.forename: Andrés M
authors.initials: AM
authors.lastname: Ruiz
mesh_terms: D000293:Adolescent; D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology; D016022:Case-Control Studies; D014355:Chagas Disease / Q000188:drug therapy* / Q000469:parasitology; D002908:Chronic Disease; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009547:Nifurtimox / Q000627:therapeutic use*; D009593:Nitroimidazoles / Q000627:therapeutic use*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014344:Trypanocidal Agents / Q000627:therapeutic use*; D014349:Trypanosoma cruzi / Q000276:immunology*; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D009593:Nitroimidazoles; D014344:Trypanocidal Agents; D009547:Nifurtimox; C009999:benzonidazole