Discussion
Chagas disease
CHAGAS DISEASE, CHRONIC CHAGAS DISEASE
Until now, there has not been an adequate parameter that reflects the early response or failure of etiological treatment for Chagas disease. Currently, the evaluation of the negativization of serology demonstrated by more than one type of conventional assay is the accepted criterion to establish successful treatment for Chagas disease [In this study, an ELISA containing a recombinant protein of the parasite (F29) was used to evaluate the serological profile in pediatric patients treated with nifurtimox and followed for 4 years post-treatment. The results clearly demonstrate conversion of ELISA F29 values to negative after antitrypanosomal therapy with nifurtimox in pediatric patients with acute and chronic Chagas disease. Similar results were observed in several previous clinical studies. In a retrospective cross-sectional study, for example, serum samples from patients with chronic Chagas disease (n = 118) followed for up to 23 years and either treated with trypanocidal therapy (nifurtimox or benznidazole) or left untreated were evaluated by ELISA F29, and its relation to conventional serology, blood parasite levels evaluated by xenodiagnosis, and clinical aspects were analyzed [It is known that different serological tests used to identify anti-In contrast to tests using a single antigen, such as the ELISA F29, the sensitivity of assays that include multiple antigens is higher, as recently shown in a multiplex serological approach [In conclusion, our results demonstrate a serological response to treatment with nifurtimox, an established antitrypanosomal drug, evidenced by a decrease in anti-F29 antibodies in children diagnosed with Chagas disease. Our results are consistent with previous studies showing that ELISA F29 is a reliable and appropriate biomarker to assess response to antitrypanosomal therapy in Chagas disease. The earlier disappearance of antibodies against F29 relative to those detected in conventional ELISAs indicates variation within the overall serological response to antitrypanosomal treatment, and may be indicative of the subsequent elimination of the parasite.