Search

An antimyeloblastic immune serum (AMS) was prepared by immunizing horses with white blood cells (WBC) from a patient with chronic myeloid leukemia (CML) in the blast crisis stage. The serum was exhausted in relation to antibodies against red and white blood cells of healthy donors. The AMS continued to have a cytotoxic action on blast cells from the blood of 20 of the 42 patients with CML in the blast crisis stage. The AMS did not react with WBC from the blood of patients with CML in the chronic phase or from patients with other forms of leukemia. Morphological observations indicate that the above-mentioned immune serum cam be used to identify antigen associated with myeloblasts from the blood of patients with CML in the blast crisis stage.

The presence of a common antigen on B lymphocytes of healthy blood donors and on myeloblasts of patients with chronic myeloid leukemia (CML) in the blast crisis (BC) stage was established with the aid of an antimyeloblast serum by the indirect surface immunofluorescence test. In the cytotoxic test this antigen was found on the blast cells of 27 patients with CML in the BC stage and in three of 11 patients with acute lymphatic leukemia, in one of eight patients with chronic lymphatic leukemia, and in both of two patients with undifferentiated leukemia. No antigen was found on the peripheral blood cells of healthy donors by this test.

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.