[Chromosome analysis and TdT determination: important prognostic parameters of blastic crises in chronic myelocytic leukemia].

To detect karyotype changes during the chronic phase of CML, 31 mostly Ph1-positive patients were followed cytogenetically over a period of 3 years. Newly emerging abnormalities, e.g. second Ph1-chromosome, iso17q, trisomy 8, could be correlated with clinical and hematological characteristics of the course of the disease if they constituted the first additional chromosomal change. In 54 patients with suspected or established blast crisis, TdT determinations were performed. Out of 27 patients with verified blast crisis, 6 showed markedly elevated enzyme activities in the leukemic blast cells. These patients proved to be very sensitive to cytostatic therapy with prednisone and vincristine. The continuous observation of TdT levels enabled us to initiate a controlled and, with respect to the quality of life, a less toxic therapy. Our data indicate that serial chromosomal analyses and TdT determinations are of great value in predicting prognosis and therapeutic responsiveness in CML.