Novel Epitope-Based Diagnostic Probes Selected by Phage Display for the Serological Detection of HDV

HDV is associated with the worst prognosis of viral hepatitis and there is a considerable lack of testing for HDV in patients. Phage display was used to select HDV mimetic peptides through biopanning, followed by DNA sequencing and phage-ELISA. Based on the sequences of the selected peptides, we constructed a recombinant protein (rHDV) for use in an Enzyme-Linked Immunosorbent Assay (ELISA). We validated the test with 87 samples (anti-HDV+) and 93 HBV controls collected from a public diagnosis laboratory in the Amazon. HDV RNA detection and sequencing were performed, and statistical analysis was conducted to determine the reactivity of the peptides and protein. rHDV exhibits a sensitivity of 74.71%, a high specificity of 97.85%, and an area under the curve (AUC) of 0.8906. According to analyses of patients with active infection, the detection parameters improved, with a sensitivity of 88.0%, specificity of 98.92%, and AUC of 0.96. In this context, the application of rHDV in an ELISA was effective at discriminating patients with hepatitis D and monoinfected patients with hepatitis B, highlighting the potential use of another efficient, fast, portable, and inexpensive platform for HDV detection.