Consecutive cytochemical staining for the analysis of the blastic population in the acute phase of chronic myeloid leukemia.

Blastic crisis in chronic myeloid leukemia is characterized by several cytological alterations which may represent some abortive attempts to differentiate along various cell lines as a consequence of a maturation defect of the myelopoietic cells. These changes of the hematological picture are associated with alterations of the karyotype and with cytochemical abnormalities of the blast cells, possibly related to their metabolic anomalies. In this regard 14 patients with blastic crisis were investigated to achieve an evaluation of the composition of the cell population during the acute phase. A sequence of three cytochemical reactions applied consecutively on the same slide (alpha-naphthyl-acetate esterase + AS D-chloro-acetate esterase + PAS) proved to be useful for the detection of differently oriented blast cells. During the acute phase of chronic myeloid leukemia only about one half of the blast cells were expressing granuloblastic differentiation. The data may be important for some clinical and prognostic factors, since the heterogeneity of the blastic population may be associated with a particular resistance to therapy.