Serological based monitoring of a cohort of patients with chronic Chagas disease treated with benznidazole in a highly endemic area of northern Argentina

This study aimed to evaluate well-documented diagnostic antigens, named B13, 1F8 and JL7 recombinant proteins, as potential markers of seroconversion in treated chagasic patients. Prospective study, involving 203 patients treated with benznidazole, was conducted from endemic areas of northern Argentina. Follow-up was possible in 107 out of them and blood samples were taken for serology and PCR assays before and 2, 3, 6, 12, 24 and 36 months after treatment initiation. Reactivity against Trypanosoma cruzi lysate and recombinant antigens was measured by ELISA. The rate of decrease of antibody titers showed nonlinear kinetics with an abrupt drop within the first three months after initiation of treatment for all studied antigens, followed by a plateau displaying a low decay until the end of follow-up. At this point, anti-B13, anti-1F8 and anti-JL7 titers were relatively close to the cut-off line, while anti-T. cruzi antibodies still remained positive. At baseline, 60.8% (45/74) of analysed patients tested positive for parasite DNA by PCR and during the follow-up period in 34 out of 45 positive samples (75.5%) could not be detected T. cruzi DNA. Our results suggest that these antigens might be useful as early markers for monitoring antiparasitic treatment in chronic Chagas disease.

Los anticuerpos antiproteínas ribosomales P estimulan al receptor ß adrenérgico en la enfermedad de Chagas pero no en el lupus eritematoso sistémico / Antibodies to ribosomal P protein of Trypanosoma cruzi in Chagas's disease possess functional autorreactivity with heart tissue and differ from anti P autoantibodies in lupus

En la búsqueda de marcadores serológicos de daño miocárdico activo en pacientes con infección crónica chagásica, se demuestra que el suero de aquéllos que presentan cardiomiopatía manifiesta reconoce las regiones C-terminales de las proteínas ribosomales P del Trypanosoma cruzi. En este estudio se demuestra que la infección no induce la respuesta autoinmune anti P que caracteriza a los pacientes con lupus, sino origina una respuesta anti P característica, expresada por los niveles elevados de anticuerpos contra las regiones polianiónicas presentes en dichas proteínas. Los anticuerpos anti P chagásicos son responsables del efecto estimulante de la IgG de los pacientes con cardiomiopatía chagásica crónica sobre los receptores ß1 adrenérgicos cardíacos, razón por la cual podrían participar en la patogenia de algunas manifestaciones de la cardiomiopatía chagásica crónica, en particular en las arritmias ventriculares. Los resultados de este trabajo indican que la actividad funcional (y patogenicidad) sobre el tejido miocárdico de los anticuerpos generados contra antígenos intracelulares del parásito resultan de su capacidad para reaccionar en forma cruzada con proteínas de la membrana celular cardíaca. Esta demostración obliga a replantear la utilización de quimioterápicos tripanomicidas eficientes y tolerados a largo plazo para anular la producción de esos anticuerpos

Human IgG responses against the N-terminal region of Merozoite Surface Protein 1 of Plasmodium vivax

The complete primary structure of the gene encoding the Merozoite Surface Protein 1 of Plasmodium vivax (PvMSP-1) revealed the existence of interspecies conserved regions among the analogous proteins of other Plasmodia species. Here, three DNA recombinant clones expressing 50, 200 and 500 amino acids from the N-terminal region of the PvMSP-1 protein were used on ELISA and protein immunoblotting assays to look at the IgG antibody responses of malaria patients from the Brasilian amazon region of Rondônia. The results showed the existance of P. vivax and P. falciparum IgG antibodies directed against PvMSP-1 antigenic determinants expressed in the clones containing the first 200 and the following 500 amino acids of the molecule, but not within the one expressing the most N-terminal 50 amino acids. Interestingly, there was no correlation between the levels of these IgG antibodies and the previous number of malariainfections