Spatial Dynamics of T and B Cell Response Predicts Clinical Outcome of Resectable and Unresectable Hepatocellular Carcinoma.

PURPOSE Immunotherapies have led to a paradigm shift in the treatment of hepatocellular carcinoma (HCC). Studies have revealed the single-cell catalogues of tumor-infiltrating immune cells and the trajectories of their differentiation. Nevertheless, the spatial distribution of these immune cells with distinct phenotypes in tumor microenvironment and their clinicopathological significance in resectable and unresectable HCCs are still largely unclear. EXPERIMENTAL DESIGN We analyzed the spatial dynamics of intratumoral CD4 and CD8 T cells and their association with B and plasma cells using 283 surgically resected HCCs, 58 unresectable HCC samples before combined immunotherapy (atezolizumab plus bevacizumab [Atezo+Bev]), and autopsy specimens from 50 cases of advanced-stage HCCs through multiplex immunohistochemistry combined with transcriptomic and driver gene mutation analysis. Classification based on the spatial dynamics of T and B cell responses (refined immunosubtype) was developed and its clinicopathological significance was analyzed. RESULTS We found that stem-like CD4 and CD8 T cells were mainly observed in T cell aggregates. Differentiation of T follicular helper cells were associated with the development of tertiary lymphoid structures, whereas differentiation of CD4 TCXCL13 cells with phenotype resembling T peripheral helper cells were associated with the development of lymphoplasmacytic microenvironment. The refined immunosubtype could predict clinical outcomes of resectable HCC after surgery and unresectable HCC after Atezo+Bev therapy. The immune microenvironment of metastatic lesions tended to reflect those of primary lesions. CONCLUSIONS We revealed the spatial dynamics of T and B cell response in HCC, which is closely associated with the clinical outcome after surgical resection or Atezo+Bev therapy.