Autologous Bone Marrow Transplantation - Blog Science Connections

The Possible Therapeutic Value of Natural Killer
Cells in Suppressing Residual Leukemic
Cells After Autologous Bone Marrow
Transplantation
Eva Lotzova and Karel A. Dicke
Natural immunity, as represented by natural killer (NK) cells, appears to be
the first line of defense against cancer (1,2). Leukemia and lymphoma targets
emerge as the most sensitive neoplasias to NK cell attack (3-5), suggesting
the primary role of NK cells in protection against malignancies of hematopoietic
and lymphoid origins. This hypothesis is in accordance with deficient
NK cell function in patients with leukemia and preleukemic disorders,
high occurrence of lymphohematopoietic malignancies in individuals with
low NK cell activity (4-6), and reinstallation of antileukemic activity in NK
cell-deficient individuals by transfer of NK cells in vivo or their stimulation with
various biological response modifying agents (5-7).
If NK cells are involved in immunosurveillance against leukemia, why,
then, do leukemic cells escape the NK cell scrutiny? One possible explanation
for this phenomenon might be the low NK cell cytotoxic function in bone
marrow (8-10), the tissue in which most of the leukemias originate. Consequently,
the absence of an appropriate NK cell surveillance mechanism in this
tissue may allow uncontrolled proliferation of leukemic cells and their spread
to the periphery. A similar mechanism may be responsible for recurrence of
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