Objective: To explore the morphological, immunophenotypical and cytogenetic (MIC) characteristics of chronic myeloid leukemia in blast crisis (CML-BC).
Methods: Marrow cells from 31 CML-BC patients were studied by bone marrow smears with morphological and cytochemical stain analysis. Immunophenotypic analysis was performed by micro blood method and flow cytometry. Cytogenetic analysis was performed using bone marrow cells prepared directly and or after 24 hours culture. RHG banding was used for karyotypic analysis.
Results: 23 patients (74.2%) were found to have myeloid blast crisis. 5 cases (16.1%) had a B-lymphoid immunophenotype and 4 of them expressed myeloid associated antigens at the same time. Another 3 cases were classified as acute undifferentiated leukemia (AUL 1 patient) and acute myeloid -lymphoid leukemia (AMLL 2 patients) with B and myeloid markers expression. A significant proportion (67.7%) of blast crisis cases were CD(34) positive. CD(34) was expressed in 80.0% of lymphoid and 65.2% of myeloid BC. Analysis of the relationship between CD(7) and CD(34) expression in blasts of myeloid crisis showed their dual expression in 8/23 (34.8%) of the cases. Cytogenetic analysis indicated that 14/27 (51.9%) of the patients had developed secondary cytogenetic abnormalities in addition to the Ph chromosome. These newly emerging abnormalities included a trisomy 8 in 3 patients, a double Ph chromosome in 3 patients, an iso chromosome 17q in 2 patients, loss of Y chromosome in 1 patent and other complicated translocation in 5 patients.
Conclusion: Blast crisis of CML is a kind of disease of stem cell. The differentiation of blast cell is blocked in the early stage. The prognosis of such patients is poor. MIC showed its important values in diagnosis, judgement of prognosis and determination of therapeutic protocol of CML-BC.