Latent effector T cells mediate immunotherapy responses in the bone marrow microenvironment

Tumor-reactive T cells in the bone marrow of patients with multiple myeloma and AML adopt a distinct effector state that differs from the exhausted tumor-infiltrating lymphocytes typically seen in solid tumors. Kehl et al. developed the TFiT classifier, which stratifies immunotherapy — but not chemotherapy — response, identifying a latent anti-tumor T-cell compartment that can be therapeutically engaged. The findings reveal a previously unrecognized immune reservoir in hematologic malignancies that may guide patient selection for immunotherapy.