The diagnosis of
visceral leishmaniasis (VL) has improved with the search of novel
antigens; however, their performance is limited when samples from VL/human immunodeficiency virus (HIV)-coinfected patients are tested. In this context, studies conducted to identify more suitable
antigens to detect both VL and VL/HIC
coinfection cases should be performed. In the current study, phage display was performed using serum samples from healthy subjects and VL, HIV-infected and VL/HIV-coinfected patients; aiming to identify novel phage-exposed
epitopes to be evaluated with this diagnostic purpose. Nine non-repetitive and valid sequences were identified, synthetized and tested as
peptides in
enzyme-linked
immunosorbent assay experiments. Results showed that three (Pep2, Pep3 and Pep4)
peptides showed excellent performance to diagnose VL and VL/
HIV coinfection, with 100% sensitivity and specificity values. The other
peptides showed sensitivity varying from 50.9 to 80.0%, as well as specificity ranging from 60.0 to 95.6%. Pep2, Pep3 and Pep4 also showed a potential prognostic effect, since specific serological reactivity was significantly decreased after patient treatment. Bioinformatics assays indicated that Leishmania
trypanothione reductase protein was predicted to contain these three conformational
epitopes. In conclusion, data suggest that Pep2, Pep3 and Pep4 could be tested for the diagnosis of VL and VL/
HIV coinfection.