The Ph1Chromosome in Childhood Leukaemia

Abstract

Ph1 [Philadelphia chromosome] positive leukemia was diagnosed in 8 of 123 (6.5%) consecutive new cases of childhood leukemia. Four patients presented as typical chronic granulocytic leukemia (CGL) and 4 as acute leukemia; 2 of the 4 children with CGL have since developed blast crisis. Morphological and immunological characterization of the blasts in these 6 acute cases was suggestive of a lymphoid crisis in 3, a mixed crisis in 2 and a myeloid crisis in 1. Remission was achieved in 5 of the 6 patients but lasted more than a yr in only 2; in 1 of these 2 patients the blasts at the time of crisis lacked the Ph1 chromosome and in the other, who presented in myeloid crisis, remission ended in a lymphoid crisis. Cytogenetic studies showed unusual translocations in 2 of the 8 children. Serial examination showed that in 3 children the proportion of Ph1 positive cells in the marrow was reduced to less than 6% at the time of remission from acute leukemia. Ph1 positive leukemia in childhood presents frequently as acute leukemia and may even mimic good risk acute lymphoblastic leukemia. The response to treatment cannot be predicted by morphological or immunological characterization of blast cells. Storage of bone marrow for possible autologous transplantation should be considered in children who achieve remission.