Comparative analysis of membrane phenotypes in acute lymphoid leukemia and in lymphoid blast crisis of chronic myeloid leukaemia

Abstract The phenotypes of acute ‘lymphoid’ and undifferentiated leukaemias (Thy-ALL, non-T, non-B ALL and ‘lymphoid’ blast crisis in Ph 1 positive leukaemia) were investigated in 45 patients. The markers included an anti-serum specific for non-T, non-B ALL (anti-ALL serum), an antiserum which reacts with B lymphocytes, non-T, non-B ALL, and some AML but not with Thy-ALL (anti-p28,33), an anti-human T lymphocyte serum (anti-HuTLA), E-rosetting (a T cell and thymocyte marker) and anti-immunoglobulin (a B cell marker). The phenotype of Thy-ALL was anti-ALL − , anti-p28,33 − , anti-HuTLA + , E + , anti-Ig − . The phenotype of non-T,non-B ALL and ‘lymphoid’ blast crisis was identical: anti-ALL + , anti-p28,33 + , anti-HuTLA − , E − , anti-Ig − . It is concluded that Thy-ALL derives from either thymic lymphocytes or a thymocyte precursor which differentiates into leukaemic cells with a Thy phenotype whereas both non-T, non-B ALL (i.e. the major subgroup of ALL) and some Philadelphia chromosome positive CML in ‘lymphoid’ blast crisis invoke a more primitive cell type of stem cell which, when malignantly transformed, has only minimal differentiation capacity.