Role of immunophenotyping in characterisation of blast crisis of chronic myeloid leukemia--a study of 25 cases.

The blast cell populations of 25 patients of chronic myeloid leukemia in blast crisis (CML-BC) were studied for morphological, cytochemical and immunophenotypic features. The patients were divided into 6 broad groups based upon the pattern of surface marker positivity-myeloblastic, mixed myeloblastic, megakaryoblastic, mixed lineage, lymphoid and undifferentiated blast crisis. Myeloperoxidase (MPO), Sudan Black B (SBB) and Chloroacetate esterase (CAE) stains showed 100% specificity for the myelomonocytic lineage but the sensitivity was low. Periodic acid Schiff (PAS) stain was neither specific nor sensitive for the lymphoid lineage. Immunophenotyping as compared to morphologic and cytochemical assessment, was seen to be most useful for assigning a lineage to leukemic cells in CML-BC.