Erythromyeloid lineage fidelity is conserved in erythroleukaemia

Blast cells from eight patients with erythroleukaemia and one with erythroid blast crisis of chronic myeloid leukaemia were studied for the co-expression of cell surface myeloid and erythroid markers, and the phenotype compared with that of erythroblasts from two patients with megaloblastic anaemia. The technique of dual indirect immunofluorescence was used with a panel of seven mouse monoclonal antibodies against well-defined myeloid antigens (CD11b, 13, 14, 15, 33 and HLA-DR) and a rat antibody, YTH89.1, specific for glycophorin A. No dual fluorescence, emanating from myeloid or erythroid lineage markers, was found to occur in either the neoplastic or non-neoplastic erythroid cells studied. These data support the hypothesis that lineage fidelity is conserved in leukaemia.