Inability to demonstrate lytic antibodies to autologous leukaemia cells in the sera from remission patients with acute myelogenous leukaemia treated with active specific immunotherapy.

The sera from seven patients with acute myelogenous leukaemia (AML) who had achieved a clinical remission and who were being maintained by weekly immunotherapy using irradiated allogeneic AML cells and BCG, were examined for the presence of antibodies which were lytic to autologous AML cells using either a complement- or cell-dependent assay. The AML cells had been stored at --179 degrees C and put into a short-term tissue culture prior to testing. At no time during the period of remission or relapse could cytotoxic activity to the autologous cells be detected, although all of the sera had lytic antibodies for some allogenic leukaemia cells. We concluded that the patients were capable of raising lytic antibodies to histocompatibility antigens but did not raise comparable lytic antibodies directed against a leukaemia-specific membrane antigen.