Cytotoxicity of lymphocytes and antibodies against autologous tumor cells in patients with myeloid leukemias and preleukemic disorders. I. Blocking activity of gp70 antigens of primate type C viruses.

Cytotoxicity of lymphocytes or antibodies against autologous tumor cells could be demonstrated very frequently in patients with chronic myeloid leukemia, whereas the presence of such cytotoxic activities was very rare in patients with acute myeloid leukemia. Lymphocytes and antibodies cytotoxic against autologous granulocytes were found in persons with potentially preleukemic cytopenic disorders. Control subjects with nonpreleukemic hematological disorders and healthy persons exhibited no cytotoxic activity. In the majority of cases the lymphocyte- or antibody-mediated cytotoxicity could be blocked with gp70 antigen of gibbon ape leukemia virus and baboon endogenous virus.