Multidimensional analyses reveal distinct immune microenvironment in hepatitis B virus-related hepatocellular carcinoma.

Background and Aims: Chronic inflammation induced by chronic hepatitis B virus (HBV) infection increases the risk of hepatocellular carcinoma (HCC). However, little is known about the immune landscape of HBV-related HCC and its influence on the design of effective cancer immunotherapeutics.
Methods: We interrogated the immune microenvironments of HBV-related HCC and non-viral-related HCC using immunohistochemistry and cytometry by time-of-flight (CyTOF). On identifying unique immune subsets enriched in HBV-related HCC, we further interrogated their phenotypes and functions using next-generation sequencing (NGS) and in vitro T-cell proliferation assays.
Results: In-depth interrogation of the immune landscapes showed that regulatory T cells (T _REG ) and CD8 ⁺ resident memory T cells (T _RM ) were enriched in HBV-related HCC, whereas Tim-3 ⁺ CD8 ⁺ T cells and CD244 ⁺ natural killer cells were enriched in non-viral-related HCC. NGS of isolated T _REG and T _RM from HBV-related HCC and non-viral-related HCC identified distinct functional signatures associated with T-cell receptor signalling, T-cell costimulation, antigen presentation and programmed cell death protein 1 (PD-1) signalling. T _REG and T _RM from HBV-related HCC expressed more PD-1 and were functionally more suppressive and exhausted than those from non-virus-related HCC. Furthermore, immunosuppression by PD-1 ⁺ T _REG could be reversed with anti-PD-1 blockade. Using multiplexed tissue immunofluorescence, we further demonstrated that T _REG and T _RM contributed to overall patient survival: T _REG were associated with a poor prognosis and T _RM were associated with a good prognosis in HCC.
Conclusion: We have shown that the HBV-related HCC microenvironment is more immunosuppressive and exhausted than the non-viral-related HCC microenvironment. Such in-depth understanding has important implications in disease management and appropriate application of immunotherapeutics.
Competing Interests: Competing interests: None declared.
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