Yasusada Miura

Effects of the in vivo Administration of Recombinant Human Granulocyte Colony‐stimulating Factor Following Cytotoxic Chemotherapy on Granulocytic Precursors in Patients with Malignant Lymphoma

We examined the effects of the in vivo administration of recombinant granulocytc colony‐stimulating factor (rhG‐CSF) on granulocytic precursors in the bone marrow of 4 patients with malignant lymphoma who received chemotherapy. Patients were treated with rhG‐CSF at doses of 100–800 μg/ m2/day intravenously for 14 days only in the first course of chemotherapy (G‐CSF course) followed by the second course of chemotherapy without rhG‐CSF which was used as a control course. In the G‐CSF course, white blood cell counts (WBCs) demonstrated a biphasic response consisting of a first peak observed within a few days after the initiation of rhG‐CSF administration, and a second peak observed on the last day of rhG‐CSF injection or the day after. In the second peak, the incidence of granulocyte‐macrophage colony‐forming units (CFU‐GM) in mononucleated bone marrow cells did not change significantly after treatment with rhG‐CSF as compared with a control. However, since the number of nucleated cells in the bone marrow increased, the absolute number of CFU‐GM in the bone marrow increased. The number of mature and immature granulocytes in the bone marrow increased. These findings suggest that G‐CSF stimulates the proliferation and differentiation of granulocytic precursors in the bone marrow in granulocytopenic patients who received cytotoxic drugs and causes mature granulocytes to be released from the bone marrow.

Multipotent and Committed CD34+ Cells in Bone Marrow Transplantation

In order to study the role of CD34+ cells in hematological recovery following bone marrow transplantation (BMT), bone marrow cells stained with HPCA‐1 (CD34) and MY‐9 (CD33) monoclonal antibodies were analyzed by using a fluorescence‐activated cell sorter on or about days 14 and 28, as well as at later times, following BMT in 6 recipients. Single cell cultures of CD34+ cells were also performed to evaluate their in vitro hematopoietic function. CD34+ cells were detectable in bone marrow cells on day 14. More than 80% of CD34+ cells co‐expressed the CD33 antigen, and macrophage (Mac) colony‐forming cells predominated among total colony‐forming cells of CD34+ cells. In normal bone marrow cells, CD34+, CD33+ cells amounted to about 40% of CD34+ cells, and the incidences of erythroid bursts, granulocyte/macrophage (GM) colonies, and Mac colonies were similar to each other. After more than 10 weeks, CD34+, CD33− cells gradually recovered, as erythroid burst colony‐forming cells increased following GM colony‐forming cells. This phenomenon was well‐correlated with the time course of peripheral blood cell recovery. CD34+, CD33+ cells as committed progenitors and CD34+, CD33− cells as multipotent stem cells have distinctive biological behaviors in BMT.

Medium pH determines the differentiation of human promyelocytic leukemia cells to basophils or eosinophils by culturing in a protein- and serum-free medium

Cells containing large basophilic granules in the cytoplasm appeared after culturing human promyelocytic leukemia cells (HL-60) in a protein- and serum-free alkaline medium. These granules were stained with toluidine blue and alcian blue. Cells were morphologically and cytochemically similar to basophils. The existence of histamine in the cell lysates was detected in both uninduced and alkaline medium-induced HL-60 cells. After culturing HL-60 cells in a protein- and serum-free acidic medium, cells containing eosin-stained small granules (eosinophils) appeared. The differentiation of HL-60 cells to basophils or eosinophils may therefore depend on medium pH by culturing in a protein- and serum-free medium.