Landscape of tumor-infiltrating immune cells in human immunogenic cancers: B cells are inversely associated with CD8T cells, but positively correlated with Treg cells

Abstract The composition of tumor-infiltrating immune cells may be a strong predictor of cancer treatment responses and survival outcomes. While B cells have been suggested to suppress T cell cytotoxicity in preclinical studies, it has been less understood whether B cells will exert immune-regulatory roles in human cancers. We explored immune cell landscapes in six human immunogenic cancers, including bladder cancer, head and neck cancer, lung adenocarcinoma, lung squamous cell carcinoma, melanoma, and renal cell carcinoma by calculating gene expression patterns of immune cell-specific metagenes in a total of 2951 cancers. We demonstrated that tumor-infiltrating activated B cells was correlated with regulatory T cell (Treg) infiltration, but had an inverse association with activated CD8 T cell infiltration consistently across all six human cancers. Tumors infiltrated by activated B cells (ActB+ tumors) demonstrated an elevated expression of regulatory cytokines and immune checkpoints, compared to tumors without infiltration by activated B cells (ActB-tumors). Activated B infiltration was not significantly associated with survival outcomes. Precis This human cancer tissue analysis showed that tumor infiltration by activated B cells correlates with decreased infiltration by activated CD8 T cells in immunogenic solid tumors, implicating B cell inhibition may enhance T cell-mediated cytotoxicity.