Abstract:

BACKGROUND: Few studies are reported at home and abroad regarding detection of leukemia stem cell concentration in childhood acute myeloid leukemia and the correlation between leukemia stem cell level in childhood acute myeloid leukemia after remission and minimal residual disease level.
OBJECTIVE: To determine leukemia stem cell level and leukemia stem cell-IPIC level in childhood acute myeloid leukemia both at initial diagnosis and at remission and correlate them to minimal residual disease level in childhood acute myeloid leukemia.
METHODS: A total of 113 samples from patients with childhood acute myeloid leukemia were collected. All heparinized bone marrow mononuclear cells were separated by cell density gradient centrifugation on ficoll-hypaque solution. After washes with PBS containing 0.1% fetal calf serum, mononuclear cell suspension was prepared. Mononuclear cells were stained with fluochrome labeled monoclonal antibodies. Leukemia stem cell level was determined and leukemia-related immunophenotypes were acquired. Immunophenotype determination and flow cytometry analysis were performed.
RESULTS AND CONCLUSION: Leukemia stem cell level in childhood acute myeloid leukemia group at initial diagnosis was significantly higher than that in acute lymphocytic leukaemia and non-malignancy control groups (both P < 0.017). The leukemia stem cell-IPIC level in childhood acute lymphocytic leukemia at initial diagnosis was significantly higher than that in the non-malignancy control group (P < 0.017). There was a significant negative correlation between leukemia stem cell level and minimal residual disease level in childhood acute myeloid leukemia. The results indicate that (1) the phenotypically same leukemia stem cell populations were also found in the bone marrow of patients with acute lymphocytic leukaemia at initial diagnosis, but the levels were not significantly different when complete remission was achieved. These phenotypically same populations were hardly found in the non-malignancy control group. (2) There was a significant negative correlation between leukemia stem cell level in childhood acute myeloid leukemia and minimal residual disease level in childhood acute myeloid leukemia patients after remission.

Key words: stem cells, embryonic stem cells, acute myeloid leukemia, acute lymphocytic leukemia, leukemia, tumor, leukemia stem cells, acute minimal residual disease, mononuclear cells, immunotype, CD34, CD38