Membrane marker analysis of 'lymphoid' and myeloid blast crisis in PH1 positive (chronic myeloid) leukemia

The membrane phenotype of leukaemic cells was analysed during different stages of chronic myeloid leukaemia by a panel of markers. These included antisera against ALL antigen, p23,30 (Ia-like structure) and other T cell, B cell and myeloid markers 'Lymphoid' blast crisis shares the phenotype of common ALL (of non-T, non-B variety). Both leukemias react with anti-ALL serum and have pre-myeloid, pre-B lymphoid and pre-thymocyte characteristics. Their phenotype may reflect the characteristics of the pluripotential stem cell from which they derive. Nevertheless both leukaemias retain their undifferentiated characteristics and lack overt myeloid, B cell and thymocyte differentiation markers. Myeloid blast crisis and AML are negative with anti-ALL serum but some of the poorly differentiated myeloblasts react with anti-p23,30 serum (and negative for SmIg). The anti-p23,30 serum (used in a double marker assay combined with anti-immunoglobulin) detects some (4-11%) intermediate sized agranular p23,30+/SmIg-cells in peripheral blood during the chronic phase of CML as well as in normal foetal bone marrow. These could be myeloid stem cells (from which in CML the myeloid blast crisis arises). The results demonstrate that surface membrane analysis can aid exact diagnosis in different stages of CML.