Cytogenetic remission in a Ph1-positive case of chronic myelogenous leukaemia

Unusual cytogenetic findings in a case of chronic myelogenous leukaemia in the course of an aplastic crisis induced by busulfan therapy are reported. The proportion of Ph1-positive cells in bone marrow aspirates fell from 100% before treatment to 8.6% following aplasia. It increased gradually during recovery, and normal cells still represented 25.7% of the metaphases 20 months later. After a 38-months' remission without therapy the disease relapsed and the Ph1 chromosome was found in 100% of the bone marrow cells.