HBV pgRNA drives chronic inflammation in CHB patients by inducing IL-1β in neutrophils

Despite advancements in antiviral therapies like nucleoside analogs (NAs), Chronic Hepatitis B (CHB) remains a significant global health burden, often progressing to cirrhosis and hepatocellular carcinoma. A key gap in understanding CHB pathogenesis is the role of viral components beyond canonical proteins in driving chronic inflammation. While HBV pregenomic RNA (pgRNA) is known as a marker of viral transcriptional activity, its direct involvement in modulating innate immunity and contributing to the persistent inflammatory state in CHB patients has been poorly understood, representing a critical area for investigation to identify novel therapeutic targets.

Researchers enrolled a cohort of 88 patients with CHB who were receiving nucleoside analogs (NAs). For a deeper mechanistic dive, samples from 8 HBeAg-negative CHB patients (4 positive for HBV pgRNA, 4 negative) underwent transcriptomic analysis. Bioinformatic tools identified common pathways, leading to experimental setups investigating platelet activation and platelet-neutrophil interactions. The study also examined the synthesis and expression of key inflammatory interleukins, specifically IL-1β, IL-17A, and the antimicrobial peptide LL-37, to elucidate the innate immune response triggered by HBV pgRNA.

HBV pgRNA was detected in 18.1% of the total study population. Transcriptomic analysis of pgRNA-positive versus pgRNA-negative patients revealed common differentially expressed genes primarily involved in platelet activation and neutrophil degranulation pathways. Further experimental validation showed that platelets stimulated with HBV pgRNA-positive serum exhibited induced autophagy and de novo synthesis of the peptide LL-37. Crucially, a combined study of platelet-neutrophil interactions demonstrated a pronounced proinflammatory phenotype, characterized by significantly high levels of IL-1β in neutrophils, which was accompanied by minimal NET formation. This suggests a specific, IL-1β-dependent inflammatory axis.

Platelets stimulated with HBV pgRNA-positive serum showed induction of autophagy and de novo synthesis of the peptide LL-37, indicating a direct role for pgRNA in cellular responses.