The use of myeloid-specific monoclonal antibodies in the diagnosis of leukemia.

Leukemia cells express a variety of cell surface antigens that have been useful in the delineation of subclasses of both lymphocytic and myeloid leukemia. In this report we describe the phenotype of cells from 50 patients with leukemia based on the results of testing for binding to four monoclonal antibodies reactive with myeloid cell-associated antigens and, in some cases, three monoclonal antibodies reactive with lymphocyte-associated antigens. We related the patterns of reactivity of these leukemia cells with the diagnosis based on morphology and histochemistry. Three of the myeloid cell-associated antigens (PMN 6, PMN 29, and AML-2-23) were expressed only on cells from patients with AML. The fourth, PM-81, was expressed on cells from 29/31 patients with AML and on 3/5 with ALL. The reactivity of the ALL cells with the J5 and B1 antibodies confirmed the diagnosis of ALL. A proposed schema for the use of these monoclonal antibodies in both the diagnosis and subclassification of leukemia is described. Finally, the significance of the heterogeneity in antigen density on leukemia cells is considered.