Microbial Translocation in the Context of Hepatitis B Infection and Hepatitis D Infection

Area of Science:

• Hepatology
• Microbiology
• Immunology

Background:

• Microbial translocation (MT) is linked to liver disease progression but is not fully understood in chronic hepatitis B virus (HBV) and hepatitis delta virus (HDV) infections.
• Understanding MT in HBV and HDV is crucial for defining disease mechanisms and potential therapeutic targets.

Purpose of the Study:

• To characterize microbial translocation and the associated immune response in patients with chronic HBV and HDV across different disease stages.
• To identify specific microbial products and bacterial species present in the systemic circulation of these patients.

Main Methods:

• Serum samples from 53 HBV, 43 HDV, and 36 healthy controls (HC) were analyzed.
• Microbial products (lipopolysaccharide, beta-glucan, peptidoglycan) and cytokine levels were measured.
• Next-generation sequencing was used to identify bacterial species in serum DNA.

Main Results:

• HBV and HDV patients showed higher levels of fungal beta-glucan and Gram-negative bacterial lipopolysaccharide compared to HC.
• Gram-positive bacterial peptidoglycan was elevated in HBV patients and correlated with pro-inflammatory cytokines (IL-1b, IL-8, IL-12p70, IL-13).
• Next-generation sequencing revealed altered bacterial taxa abundance, with a higher proportion of Gram-positive genera in severe disease, associated with increased cytokine levels.

Conclusions:

• Patients with chronic HBV and HDV exhibit increased translocation of bacterial and fungal products into their bloodstream.
• An elevated proportion of Gram-positive bacteria in the serum is associated with disease progression in HBV and HDV.
• The correlation between peptidoglycan and cytokines suggests specific microbial components may drive systemic inflammation and contribute to disease advancement.