Single-cell transcriptomic profiling reveals dysregulation of B-cell subset function in patients with chronic hepatitis B.

Abstract

Background and aim: The goal of this study was to investigate the immunological characteristics and potential clinical significance of B-cell subsets during different phases of hepatitis B virus (HBV) infection.

Methods: We conducted single-cell RNA sequencing on 23,967 B cells (including 1,677 plasma cells) derived from 46 liver and blood samples from 25 individuals. The study included six HBV-free healthy control (HC) cases, as well as subjects from four different HBV phases: six immune-tolerant (IT), six immune activation (IA), four acute recovery (AR), and three chronic resolved (CR) individuals. In addition, a separate cohort consisting of 10 IT, 13 IA, and 15 HC individuals was recruited for experimental validation.

Results: The liver tissue of patients with chronic hepatitis B (CHB) exhibited enriched atypical B-cell (ABC) and FCRL1⁺ B-cell subsets compared to their peripheral blood. Specifically, the ABC subset was enriched in the liver tissue of the IT patients and specifically overexpressed immune-tolerance-related genes, such as TNFRSF1B, ADGRE5, ZBTB32, and GRN. Conversely, the FCRL1⁺ B-cell subset was enriched in the liver tissue of the IA patients and characterized by a high expression of immune-activation-related genes, including TNFRSF13C, LY9, FCRL1, CD55, and NFKB1. Similarly, the distribution patterns of ABC and FCRL1⁺ B cells in IT and IA patients were also confirmed in peripheral blood through parallel analyses and flow cytometry validation. Additionally, the CHB patients demonstrated abnormal plasma cell (PC) differentiation compared with the CR patients. For instance, the IT patients exhibited a low expression of SEC61A1 in their plasma cells (PCs), while the IA patients demonstrated a reduced expression of TNFRSF17; both molecules are critical to the maturation and functional activity of antibody-secreting cells.

Conclusion: Our study provides a comprehensive analysis of the composition and functional characteristics of B-cell subsets in HBV-infected individuals at various clinical phases. It also identifies the potential mechanism responsible for humoral immunity in cases of HBV infection.