ABSTRACT
BACKGROUND: The hemopoietic stem cells increase in number during the regeneration after chemotherapy or bone marrow transplantation (BMT). Although the proportion of hemopoietic stem cells and their differentiation have been studied by immunophenotyping using the flow cytometry, no substantial research efforts have been directed toward the regenerating marrow. We attempted to discover the proportions of undifferentiated stem cells, committed stem cells, B cell precursors, and myeloid precursors in the regenerating bone marrows during complete remission (CR) and after engraftment of BMT. METHODS: Bone marrow samples from 82 patients with acute leukemia in CR and from 25 patients after BMT engraftment, along with 22 control samples, were used to find the numbers of CD38-/CD34+, CD38+/CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells in the large lymphocyte gate by flow cytometry. We cross-analyzed our results in terms of groups: CR, BMT, and initial diagnosis groups. We performed significance tests on age, relapse, chromosomal abnormalities, clinical outcomes, and initial immunophenotypes of the leukemic cells. RESULTS: The proportions of CD38-/CD34+, CD38+/CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells are more highly distributed in acute B-lymphoblastic leukemia than the normal group and also in the CR than the BMT group. CD19+/CD34+ cells were increased in the relapse group and CD38+/ CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells were increased in the group with chromosomal abnormality. The results were irrelevant to the initial immunophenotype of the leukemic blasts. CONCLUSIONS: The increases of the markers spanned too widely to apply one specific cutoff value to analyze them. They seemed to be the results of normal regeneration, irrelevant to relapse or initial immunophenotype of leukemic blasts.