Involvement of the Erythroid Series in Blastic Crisis of Chronic Myeloid Leukaemia. FURTHER EVIDENCE FOR THE PRESENCE OF PHILADELPHIA CHROMOSOME IN ERYTHROBLASTS

Abstract

I nvolvement of the erythroid series in chronic myeloid leukaemia may be evidenced haematologically by a normochromic anaemia with anisocytosis, the presence of circulating normoblasts, the presence of bizarre normoblasts in the marrow and peripheral blood, and rarely the presence of sideroblasts. The Philadelphia (Ph 1 ) chromosome has been assumed to be present in the erythrocyte as well as the granulocyte series on good but circumstantial evidence and it is generally agreed that the leukaemic process probably affects the basic stem cell of the red cells, granulocytes and platelets. When blastic crisis occurs there is an increase in the percentage of blast cells in marrow and peripheral blood, and anaemia, thrombocytopenia and resistance to therapy accompany the apparently irreversible downward clinical course. Aneuploid cell lines emerge (Hammouda, Quaglino and Hayhoe, 1964). We are here presenting evidence that aneuploid Ph 1 ‐positive cell lines are also found in the erythroid cells in blastic crisis and therefore that when this occurs the essential change may also affect the basic stem cell. In a case of chronic myeloid leukaemia seen recently, a sideroblastic phase was found terminally and it was possible to combine standard cytogenetic methods with Perls's prussian blue stain for iron and demonstrate siderotic granules in the cytoplasm surrounding Ph 1 ‐positive aneuploid chromosome spreads. We thus prove the erythroid nature of these spreads, and incidentally provide more direct evidence than offered hitherto, for the presence of the Ph 1 chromosome in the erythroid cells.