Characterization of antigens on acute lymphoblastic leukemias.

Detectable differences in surface membrane characteristics of normal lymphocyte populations have facilitated the classification of leukemic cells according to cell origin and Stage of differentiation. Recent reports show that distinct leukemic cell populations do not only express markers found on normal cell populations. Using specific antisera new antigenic determinants on cells of common acute lymphoblastic leukemia (cALL) and cells of some chronic myeloid leukemias (CML) in blast crisis have been identified [ l , 111. The discovery of a cALL-antigen allows the identification of further subgroups of ALL, which has already been described as a heterogenous disease by clinical and morphological criteria [4]. The nature of the cALL-antigen and the question of its occurence during normal hemopoietic development is still speculative. Our studies investigate the distribution of cALL-antigen in correlation with common markers on normal cells, cell lines and leukemic cells of a major group of ALL patients and analyze the effect of anti-cALL antibodies On hemopoietic precursor cell populations.