Immunophenotypic characteristics of the blast : Experience at princess iman research and laboratory sciences center

Abstract EN

Objective: To characterize the Immunophenotypic of the blast cell population in 14 patients with Philadelphia chromosome-positive chronic myelogenous leukemia in blastic crisis (CML-BC) at Princess Iman Research and Laboratory Sciences Center. Methods: Bone marrow or peripheral blood smears from 14 CML-BC patients diagnosed at Princess Iman Research and Laboratory Sciences Center during the years 2001 to 2004 were studied by morphological and cytochemical stain analysis.

Immunophenotypic analysis was performed by flow cytometry using a panel of 22 monoclonal antibodies. Results: Cytochemical stain analysis correlated with immunophenotyping results.

Twelve patients (86%) were found to have myeloid blast crisis and two patients (14%) had lymphoid blast crisis.

The blast crisis were divided into subtypes as de novo acute leukemias: Of the twelve myeloid blast crisis six were differentiated, one had myelomonocytic differentiation, another one had monocytic differentiation and two had megakaryocyte differentiation.

In the lymphoid blast crisis one case displayed a mature B cell phenotype while the other case displayed a precursor B cell phenotype.

There were two cases transformed to acute myeloid leukaemia after bone marrow transplantation and were diagnosed by cytochemistry only.

No T-lymphoid, mixed lineage or undifferentiated blast crisis were observed.

The blast cells in both myeloid blast crisis and lymphoid blast crisis displayed the same marker profile as those seen in acute leukemias.

CD34 was expressed in all cases of myeloid blast crisis.

Coexpression of CD34 and CD7 was observed in one case of myeloid blast crisis with megakaryocytic differentiation. Conclusion: our findings are comparable to those found in the literature.

Immunophenotyping is important in distinguishing between a myeloid and lymphoid blast crisis, thus providing clinically useful information for the designing of treatment protocols and the judgment of prognosis.

A sub classification as in acute leukemia is possible.

A study of cytogenetic characteristics of CML-BC is planned.