- Lymphokine-activated killer (LAK) precursor cell activity is present in infused peripheral blood stem cells and in the blood after autologous peripheral blood stem cell transplantation. Neubauer, M.A., Benyunes, M.C., Thompson, J.A., Bensinger, W.I., Lindgren, C.G., Buckner, C.D., Fefer, A. Bone Marrow Transplant. (1994)