Analysis of human myelogenous leukemia cells in the fluorescence- activated cell sorter using a tumor-specific antiserum

The properties of a rabbit antiserum (anti-AML) raised to a purified protein from membranes of human acute myelogenous leukemia (AML) cells is described. Bone marrow and peripheral blood leukocytes (PBL) from either normal individuals or patients with either myeloproliferative or other disorders were analyzed in a fluorescence-activated cell sorter (FACS IV) after labeling with anti-AML, normal rabbit serum (NRS), or antiserum raised to normal human membrane antigens. Of 40 cell samples from patients with acute myelogenous leukemia, 39 reacted strongly with the anti-AML antiserum. Similarly, all of 19 specimens from patients with chronic granulocytic leukemia reacted with the anti-AML. When 42 bone marrow or PBL samples from patients with a variety of lymphoproliferative disorders were examined, 2 specimens reacted with the antiserum, both from individuals with diagnoses of acute lymphocytic leukemia (ALL). None of the 14 normal bone marrow or PBL donor specimens tested reacted with the antiserum. It was also found that essentially all samples from patients in clinical remission from AML had high numbers of cells reactive with the anti-AML. When cells from such individuals were labeled and sorted on the FACS IV, it was found that cells fluorescing strongly with the anti-AML contained cells of both myeloid and lymphoid origin. The implications of these results are discussed.