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Glioblastoma (GBM) demonstrates extensive immunomodulatory mechanisms that challenge effective therapeutic interventions. These phenomena extend well beyond the tumor microenvironment (TME) and are reflected in the circulating immunophenotype. B lymphocytes (B cells) have received limited attention in GBM studies despite their emerging importance in mediating both local and systemic immune responses. Recent findings highlight the complex regulatory interactions between B cells and other immune cell populations, including tumor-infiltrating macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and other infiltrating lymphocytes (TILs). B cells are believed to hinder the efficacy of modern immunotherapy strategies focusing on T cells.

This is a focused review of available evidence regarding B cells in GBM through January 2025.

Peripheral blood reflects a systemically dampened immune response, with sustained lymphopenia, increased plasma cells, and dysfunctional memory B cells. The tumor immune landscape is enriched in cells of B-lineage. Subsets of poorly characterized B regulatory cells (Bregs) populate the TME, developing their phenotype due to their proximity to MDSCs, TAMs, and tumoral cells. The Bregs inhibit CD8⁺ T activity and may have potential prognostic significance.

Understanding the role of B cells, how they are recruited, and their differentiation shifted towards an immunomodulatory role could inform better therapeutic strategies and unleash their full antitumoral potential in GBM.

© 2025. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

PMID:40080248