Work

Metagenomic study in a predominantly adult cohort with hepatitis of unknown etiology

Year: 2026

Type: article

Abstract: Hepatitis of unknown origin (HUO) remains a diagnostic challenge in clinical hepatology, with a substantial proportion of cases lacking identifiable etiologies after standard serological, biochemical, and imaging evaluations. While metagenomic sequencing has been extensively applied in pediatric hepatitis outbreaks, its utility in predominantly adult HUO cohorts remains underexplored. This study aimed to characterize the plasma and fecal virome in patients with HUO (48 adults and one adolescent aged 16 years) using metagenomic approaches, and to explore whether known or novel pathogenic agents could be identified within this cohort. A total of 49 patients diagnosed with HUO at Beijing Ditan Hospital between June 2024 and December 2024 were enrolled, all of whom met strict inclusion criteria excluding established etiologies including hepatitis A-E viruses, alcoholic liver disease, drug-induced liver injury, autoimmune hepatitis, metabolic disorders, and biliary obstruction. A total of 59 samples (comprising 44 plasma and 15 fecal specimens) were subjected to ultra-multiplex targeted ribonucleic acid (RNA) sequencing (covering 139 RNA viruses) and unbiased metagenomic sequencing. Pathogen profiles and viral community structures were systematically analyzed through a dedicated bioinformatics pipeline. Targeted sequencing detected hepatitis C virus (HCV) in one plasma sample, which was subsequently confirmed by follow-up RT-PCR and seroconversion, while metagenomic sequencing identified hepatitis B virus (HBV) sequences in another patient, along with sporadic detection of goose circovirus in one fecal sample and an unconfirmed low-level influenza A-like sequencing signal in one plasma sample. The confirmed HCV finding led to reclassification of one case, whereas the other viral signals remained of uncertain clinical significance. Viral community analysis revealed apparent divergence between plasma and fecal samples, with visually distinct niche-specific viral profiles as shown by hierarchical clustering. This exploratory study failed to identify a common pathogenic agent in this HUO cohort, underscoring the etiological heterogeneity of this condition. The detection of known hepatotropic viruses in patients initially classified as HUO highlights the potential added value of metagenomic sequencing in complementing conventional serological testing and suggests that some HUO cases may be reclassified as conventional viral hepatitis with improved diagnostic resolution. Larger controlled cohort studies are warranted to validate these findings.

Source: Biosafety and Health

DOI: 10.1016/j.bsheal.2026.09.003