Kouiti Inokuchi

Effects of interleukin-1 and tumor necrosis factor on megakaryocytopoiesis: mechanism of reactive thrombocytosis.

We studied the effects of interleukin-1 (IL-1) and tumor necrosis factor (TNF) on mouse megakaryocytopoiesis to evaluate the role of these cytokines in reactive thrombocytosis associated with inflammation. Injections of IL-1 or TNF to mice induced a significant increase in the megakaryocyte progenitor cell (CFU-Meg) count in the spleen. When IL-1 and TNF were injected simultaneously, the splenic CFU-Meg count was remarkably increased compared with mice injected with either IL-1 (p < 0.003) or TNF (p < 0.001) alone. On the other hand, neither IL-1 nor TNF showed any megakaryocyte-potentiating or -stimulating effects in vitro. In the sera obtained 4 h after administration of IL-1, TNF or both, high megakaryocyte potentiating activities were found. Furthermore, an extremely high level of IL-6 was detected in the serum after administration of both IL-1 and TNF. These results strongly suggest that IL-1 and TNF stimulate megakaryocytopoiesis indirectly via other cytokine(s) induced from accessory cells, and that increased levels of IL-1 and TNF play important roles in the development of reactive thrombocytosis caused by inflammation.

Megakaryocyte, Erythroid and Granulocyte-Macrophage Colony Formation in Myelodysplastic Syndromes

Bone marrow progenitor cell assays of three cell lineages, i.e., colony-forming unit megakaryocytes (CFU-Meg), burst-forming unit erythrocytes (BFU-E) and colony-forming unit granulocyte-macrophages (CFU-GM), were performed for 21 patients with myelodysplastic syndromes (MDS). Markedly reduced or absent colony formation was found in 67% of the patients for CFU-Meg and all patients except 2 with refractory anemia (RA) for BFU-E. Abnormal CFU-GM colony formation was found in only 5 of 12 patients with RA and RA with ring sideroblasts, in contrast to all of the RA patients with excess of blasts and excess of blasts in transformation. Defective colony formation of all three cell lineages was seen in 63% of the MDS patients. The colony number of CFU-Meg correlated significantly with the numbers of both BFU-E and CFU-GM. These findings indicate that hematopoiesis in MDS patients is disturbed due to a qualitative or quantitative defect at the multipotent stem cell level.

Chemotherapy for minimally differentiated acute myeloid leukemia (AML-M0) : a report on five cases and review of the literature

SummaryWith the objective of establishing the optimal therapy for minimally differentiated acute myeloid leukemia (AML-M0), we examined the therapeutic results of five AML-M0 cases and reviewed the literature. In a series of 63 patients with newly diagnosed acute leukemia who were admitted to the Main Hospital of Nippon Medical School, five patients fit the criteria for AML-M0: negative myeloperoxidase (MPO) and Sudan black B reaction by light microscopy, negative for B- and T-lineage markers, and positive for myeloid markers. They were treated by means of AdVP [adriamycin, vincristine, and prednisolone (PSL)] therapy and/or BHAC-DMP [behenoylcytosine arabinoside (BHAC), daunorubicin (DNR), 6-mercaptopurine (6-MP), and PSL] therapy. The AdVP therapy was unsuccessful in the two patients who received it, while a complete remission (CR) was achieved with the BHAC-DMP therapy in three of four patients. Although one patient treated with BHAC-DMP did not achieve CR, his blasts were apparently sensitive to the therapy. In assessable cases in the literature where leukemic blasts were MPO-negative, myeloid marker-positive and B- and T-lineage marker-negative, CR was achieved in 54.5% and 44.4% with anti-acute myeloid leukemia therapy and anti-acute lymphocytic leukemia therapy, respectively. Five cases in the literature were treated with a chemotherapeutic regimen containing BHAC [or cytosine arabinoside (Ara-C)], DNR, and 6-MP, and all achieved CR. The regimen containing BHAC (or Ara-C), DNR, and 6-MP may be useful as induction chemotherapy for AML-MO.