Demonstration of antibodies binding to autologous and allogeneic leukemic cells in childhood ALL. Evidence for a common ALL antigen(s).

The humoral immune response to autologous leukemic cells was investigated in childhood ALL using a 125I protein A binding assay. In 5/7 patients antibodies were demonstrated at diagnosis and in 3/7 cases also after chemotherapy. Sera from 2/3 patients, which bound significantly to autologous leukemic cells, did not bind significantly to autologous remission cells. In allogeneic experiments sera bound significantly to ALL leukemic cells (6/7 positive combinations), but not to AML leukemic cells (8/8 negative combinations). We propose that ALL sera contain antibodies binding to autologous leukemic cells and that they are directed against a common ALL antigen(s).