Classification of Leukemic Cells with T- and O-ALL-Specific Antisera

Abstract

After the discovery of several surface markers on human lymphocyte populations many attempts have been made to classify leukemias and lymphomas on the basis of cell origin or cell characteristics. Although the biological implications of the various markers on leukemic cells are unknown, an exact characterization of these markers may lead to an early diagnosis of preleukemic stages or relapses and provide guidelines for more specific therapeutic regimens of these disorders. The panel of common surface markers was increased by recent reports on specific xenogeneic antisera identifying membrane antigens on different types of leukemia cells. The identification of the T-cell antigen by specific anti-T-cell sera on leukemias that formed spontaneous rosettes provided convincing evidence that these cells derived from the thymic pathway (3, 13, 16, 12). An antigen not present on normal mature lymphocytes was recently detected on cells of a subgroup of ALL cases by antisera which were produced against so-called O-ALL lymphoblasts lacking all the known markers (7). On the other hand, raising of diagnostic antisera against human lymphatic or leukemic tissues in other species is complicated by the fact that these sera are generally directed against xeno-specific determinants including many cells other than those used for immunization (25). Extensive absorption and purification procedures must therefore be performed to guarantee a definite specificity (22). In this report we describe the reaction pattern of an absorbed anti-T-cell-globulin (ATCG) and an anti-O-ALL-globulin (A-O-ALL-G) and their application to the classification of leukemias in several test systems.