[Cytogenetic monitoring acute myeloid leucosis in children].

Preliminary results of cytogenetic monitoring acute myeloid leukosis (AML) in children are presented. Repeated chromosomal analyses were accomplished in 23 patients that presented with cell clones showing various karyotype abnormalities prior to the onset of therapy. All the patients were treated following identical protocols. Complete hematological remission was achieved in 20 cases. The majority of patients did not have cells with chromosomal abnormalities changes after a 2-4 month follow up. Anomalous metaphases persisted in 6 patients although their occurrence decreased. Five of them poorly responded to therapy whereas simultaneous achievement of morphological and cytogenetic remission ensured more beneficial outcome of the treatment. Results of the study agree with recent reports of delayed reversion to normal karyotype under effect of AML therapy that as a rule predicts an unfavourable prognosis Repeated analysis during stable hematological remission did not reveal cells with karyotype abnormalities in bone marrow with the exception of a single patient who had marrow cells with chromosomal translocation (16:16) up to the 8th month of complete hematological remission. This patient remains under observation (duration of remission is now 15 months). It was shown that the relative amount of cells with abnormal karyotype in bone marrow frequently exceeds that of blast cells (usually before the onset of therapy and sometimes in the beginning of morphological remission). During stable remission, such an excess is an antecedent of relapse. It is concluded that cytogenetic analysis for monitoring AML extends the possibility of detecting leukemia cells.

[Specific features of stem cell (CD34+) subvariant of acute lymphoblast cell leukemia in children]. / Osobennosti stvolovokletochnogo (CD34+) podvarianta ostrogo limfoblastnogo lekoza u detei.

The authors have examined 134 children with acute lymphoblast cell leukemia (ALCL) who were treated at the Research Institute of Pediatric Oncology and Hematology, Russian Cancer Research Center, in January 1990 to November 1999, and followed up till March 1, 1999. The mean duration of follow-ups was 57.46 +/- 2.87 months. The minimum follow-up was 4 months. The immunophenotypical features of stem cell immunological subvariant of ALCL identified from the presence of 10% or 15% of CD34+ lymphoblast cells were similar in the leukemia clone. There is evidence for the isolation of the least mature, stem-cell immunological subvariant of ALCL in children. The immunophenotypic features of stem-cell ALCL in children were as follows: the expression of myeloid antigens (linear and different marker leukemias) and the higher rates of involvement of B-cell leukemias. The clinical and hematological features of stem-cell versus CD34-negative ALCL in children were the low levels of leukocytes (p = 0.009) and blast cells (p = 0.018) in the peripheral blood at diagnosis. At the same time, stem-cell ALCL showed a poorer prognosis. Moreover, blast cell CD34 antigen expression deteriorated prognosis for pre-pre-B (common) immunological variant of ALCL (p = 0.035). Intensified ALCL treatment programmes improved relapseless survival of patients with stem-cell ALCL (p = 0.0042).