MOLECULAR EVIDENCE FOR A COMMON LEUKEMIC PROGENITOR IN ACUTE MIXED LYMPHOID AND MYELOID-LEUKEMIA

De novo acute leukaemia presenting with a mixed lymphoid and myeloid l eukaemic population has rarely been described. We have used the consen sus Ig heavy chain primers and DNA isolated from these two distinct po pulations of cells in polymerase chain reactions. We demonstrated that both populations of cells exhibited Ig heavy chain gene rearrangement s. Cloning and subsequent DNA sequencing of the amplified products sho wed a common V-D-J junctional nucleotide sequence. This work therefore provides the first evidence that the leukaemic cells in de novo acute leukaemia with a mixed lymphoid and myeloid population are derived fr om a common progenitor clone and may offer an explanation for the poor prognosis in these patients.