Comparing in vivo bioluminescence imaging and the Multi-Cruzi immunoassay platform to develop improved Chagas disease diagnostic procedures and biomarkers for monitoring parasitological cure

Background Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is a serious public health problem throughout Latin America. With 6 million people infected, there is a major international effort to develop new drugs. In the chronic phase of the disease, the parasite burden is extremely low, infections are highly focal at a tissue/organ level, and bloodstream parasites are only intermittently detectable. As a result, clinical trials are constrained by difficulties associated with determining parasitological cure. Even highly sensitive PCR methodologies can be unreliable, with a tendency to produce false-cure readouts. Improved diagnostic techniques and biomarkers for cure are therefore an important medical need. Methodology/Principal findings Using an experimental mouse model, we have combined a multiplex assay system and highly sensitive bioluminescence imaging to evaluate serological procedures for diagnosis of T. cruzi infections and confirmation of parasitological cure. We identified a set of three antigens that in the context of the multiplex serology system, provide a rapid, reactive and highly accurate read-out of both acute and chronic T. cruzi infection. In addition, we describe specific antibody responses where down-regulation can be correlated with benznidazole-mediated parasite reduction and others where upregulation is associated with persistent infection. One specific antibody (IBAG39) highly correlated with the bioluminescence flux and represents a promising therapy monitoring biomarker in mice. Conclusions/Significance Robust, high-throughput methodologies for monitoring the efficacy of anti-T. cruzi drug treatment are urgently required. Using our experimental systems, we have identified markers of infection or parasite reduction that merit assessing in a clinical setting for the longitudinal monitoring of drug-treated patients.

Automated summary

This study evaluated serological procedures for the diagnosis of T. cruzi infections and confirmation of parasitological cure using an experimental mouse model. The researchers identified a set of antigens that provide a rapid and accurate read-out of both acute and chronic T. cruzi infection. They also discovered specific antibody responses that can be correlated with parasite reduction or persistent infection. These findings could be used to develop diagnostic techniques and biomarkers for monitoring the efficacy of anti-T. cruzi drug treatment in a clinical setting.