The diagnosis of
leishmaniasis presents problems due to the variable sensitivity and/or specificity of tests. In addition, high levels of anti-parasite
antibodies can remain
after treatment, making it difficult to conduct a prognostic follow-up of patients. In this context, it is necessary to identify new candidates to be examined for the sensitive and specific diagnosis of the disease. In the present study, four Leishmania
proteins, previously shown as antigenic for tegumentary
leishmaniasis (TL), were evaluated, and their linear specific
B-cell epitopes were predicted and used to generate a new gene codifying chimeric
protein called ChimB, which was cloned, and the recombinant version was expressed, purified, and evaluated in ELISA (
Enzyme-Linked
Immunosorbent Assay) to diagnose TL and
visceral leishmaniasis (VL). A total of 220 human serum samples were used, and, when ChimB was used, results showed sensitivity, specificity, and positive and negative predictive values of 100% for the diagnosis of both diseases; however, when using
peptides, the sensitivity values reached from 28.0% to 57.3% and specificity varied from 16.3% to 83.7%. A soluble Leishmania extract (SLA) showed sensitivity and specificity values of 30.7% and 45.9%, respectively. The area under the curve (AUC) value for ChimB was 1.0, while for synthetic
peptides, this value reached between 0.502 and 0.635, whereas for SLA, the value was of 0.589. Serological assays using sera samples collected before and
after treatment showed significant reductions in the anti-ChimB antibody levels after
therapy, suggesting a prognostic role of this recombinant
antigen. In conclusion, preliminary data suggest the use from ChimB as a potential candidate for the diagnosis and prognosis of
leishmaniasis.