Specific xenogenous antiserum to cells of chronic myeloid leukemia (CML) in blastic crisis.

The antiserum was obtained from horses immunized with cells from patients with blastic crisis of CML and completely absorbed with normal white blood cells (WBC). The absorbed antiserum remained cytotoxic to blast cells from nearly half of the patients in blastic crisis and did not react with WBC from patients with Acute Myeloid Leukemia (AML), Acute Lymphoid Leukemia (ALL), Chronic Lymphoid Leukemia (CLL) and Chronic Myeloid Leukemia (CML) in its chronic phase as well as with cells of human normal bone marrow or fetal liver.