Characterization of NKR + T-cell subsets in human bone marrow: implications for immunosurveillance of neoplasia

In addition to hematopoietic progenitors, human bone marrow contains mature T/NK lymphocytes. Vα24Vβ11 NKT-cells, a subset of NK receptor + (NKR +) T-cells in humans, are rare in bone marrow, suggesting the presence of other NKR + T-cells which may contribute to tumor surveillance. NKR +/− T-cells were examined in blood (PB), and bone marrow from donors (DM) and patients with active hematopoietic malignancy (PM), or in remission (PR). T-cells in PR & PM were enriched for CD56 + and CD57 + subsets, compared to DM. All marrow NKR +/− T-cell subsets were more activated than PB. PM and, surprisingly, PR marrow contained more activated cells than DM. CD8 + cells were significantly increased in all patient marrows and there was evidence of the formation of an effector/memory pool in malignant marrow. These data suggest that NKR + T-cell enrichment in human bone marrow that has been exposed to neoplastic transformation is compatible with a role in localized tumor surveillance/eradication.