Spatial immune profiling reveals lymphocyte confinement to myeloid-mesenchymal niches and heterogeneous therapeutic T-cell opportunity in pediatric ependymoma

A study analyzing pediatric posterior fossa group A (PFA) ependymoma brain tumors using spatial transcriptomics reveals previously uncharacterized immune niches and therapeutic opportunities for T-cell treatment. Traditionally considered an immune-cold tumor, PFA ependymoma exhibits lymphocyte hotspots, dominated by inflammatory and retention-associated transcriptional states, rather than cytotoxic or exhausted programs.

These lymphocyte hotspots are confined to myeloid- and mesenchymal-rich tumor zones, with minimal presence in epithelial regions. The researchers identified four potential restriction axes for ligand-receptor interactions, including SPP1-CD44, FN1-integrin, collagen VI-integrin, and APP-CD74. An analysis of immunotherapy opportunity scoring showed heterogeneous and spatially compartmentalized beta and gamma delta T cell recognition landscapes.

Beta T ligand availability and immunosuppressive tone increased in the mesenchymal compartment, while two components of gamma delta phosphoantigen-mediated recognition were found to be spatially and transcriptionally distinct. These findings challenge the notion of PFA ependymoma as an immune desolate tumor and present a computationally viable method for mapping immune architecture and assessing T cell therapy susceptibility in low-infiltrated pediatric central nervous system tumors.