Abstract

Background: HIV infection accelerates the natural history of HBV-related liver disease. The mechanisms by which this occurs are incompletely understood due to limited access to comparable groups of people living with HBV with/without HIV and lack of access to the liver compartment. In the context of a unique HBV clinical cohort in Zambia, where 20% of people with chronic HBV infection have HIV coinfection, we collected liver cells with fine needle aspiration (FNA) and compared cell milieu and expression patterns by HIV infection status.

Methods: Treatment-naïve adults with either HBV/HIV coinfection or antiviral treatment-eligible chronic HBV monoinfection were enrolled in an observational cohort in Lusaka, Zambia, and underwent liver FNAs. Liver cells were loaded into the HIVE device (Honeycomb Biotechnologies), which permits a field site to capture and stabilize the full spectrum of intrahepatic cells for subsequent analysis at a distant site via single-cell RNA sequencing. We analyzed the intrahepatic gene expression (in a total of 7,992 high-quality cells) in 12 participants, including 6 with HBV/HIV coinfection.

Results: The median age of analyzed participants was 31 years (range: 20-45), 4 (33.3%) were female (2 in each group), and half had HIV coinfection. Participants with coinfection had a median peripheral CD4 count of 225 cells/mm³ (range: 69-999). Overall, HBV/HIV coinfection was associated with increased frequencies of CD8+ T cells and decreased frequencies of neutrophils and B cells. S100, MHC-II, and interferon-stimulated genes (ISG) were recurring gene programs in the myeloid compartment, with distinct expression patterns in each cell type. Significant differences in gene expression by HIV status were seen across a range of immune cell types, and distinct expression patterns were detected within subpopulations. HBV/HIV coinfection was associated with increased expression of ISG and higher signaling of PD-1/PD-L1 in neutrophils, which was paralleled by increased PD-1 expression in CD8+ T cells.

Conclusion: Through single-cell analysis of liver FNAs, we observed pre-treatment differences in the intrahepatic milieu between adults with HBV/HIV coinfection and HBV monoinfection. A higher basal level of innate immune ISG and PD-1/PD-L1 signaling suggests possible unique mechanisms by which HIV coinfection accelerates HBV-related liver disease. This work also demonstrates the feasibility of FNA-based single-cell sequencing from remote sites.