Non-A, non-B hepatitis specific antibodies directed at host-derived epitope: implication for an autoimmune process

Area of Science:

• Virology
• Immunology
• Hepatology

Background:

• Human non-A, non-B hepatitis (NANBH) diagnosis remains challenging.
• Hepatitis C virus (HCV) is a major cause of NANBH, but not all cases are explained by known HCV sequences.
• Host cellular responses may play a role in NANBH pathogenesis.

Purpose of the Study:

• To investigate a novel epitope (GOR epitope) identified from chimpanzee plasma infected with NANBH agent.
• To develop and validate an enzyme-linked immunosorbent assay (ELISA) for antibodies against the GOR epitope (anti-GOR).
• To assess the diagnostic utility of anti-GOR for NANBH and its potential role in reducing post-transfusion hepatitis.

Main Methods:

• Isolation of a cDNA clone (GOR47-1) encoding the GOR epitope from infected chimpanzee plasma.
• Development of an enzyme-linked immunosorbent assay (ELISA) to detect anti-GOR antibodies.
• Serological analysis of patient cohorts including acute NANBH, chronic NANBH, NANB liver cirrhosis, and primary hepatocellular carcinoma.
• Comparison of anti-GOR prevalence with anti-HCV status and detection of HCV-RNA using polymerase chain reaction (PCR).

Main Results:

• The GOR epitope was encoded by a host cellular sequence, not reported HCV sequences.
• Anti-GOR antibodies (IgM and IgG) were detected in a patient with acute NANBH.
• High prevalence of anti-GOR was observed in patients with chronic NANBH (81%), NANB liver cirrhosis (65%), and NANB hepatocellular carcinoma (63%).
• Anti-GOR was rarely detected in patients with other liver diseases or healthy donors (<10%).
• HCV-RNA was detected in most anti-GOR positive patients who were negative for anti-HCV.

Conclusions:

• The GOR epitope represents a host-derived marker potentially associated with NANBH.
• The anti-GOR ELISA is a valuable tool for diagnosing NANBH, especially in anti-HCV negative cases.
• Detection of anti-GOR may aid in identifying individuals at risk and reducing post-transfusion hepatitis.