ABSTRACT
The term ‘chronic myeloid leukaemia’ (CML) describes a specific form of leukaemia characterized by progressive splenomegaly, leukocytosis, anaemia, marrow hypercellularity and the finding in most cases of the Philadelphia (Ph) chromosome (Figure 4.1) in all dividing cells of the myeloid series and in some B-lymphocytes. Between 5 and 10% of patients with CML have variant features, such as typical CML without the Ph chromosome, haematologically atypical CML (also Ph-negative), juvenile chronic myeloid leukaemia and various forms of the myelodysplastic syndrome. It is likely that Ph-positive CML together with the rare Ph-negative BCR/ABL-positive CML patients are a relatively homogeneous group, and indications for and results of bonemarrow transplant (BMT) in this group cannot necessarily be extrapolated to other patients.
