Shin-ichiro Kuriya

Recombinant human c‐Mpl ligand is not a direct stimulator of proplatelet formation in mature human megakaryocytes

To evaluate the effect of the c‐Mpl ligand on platelet production by megakaryocytes, we investigated proplatelet formation in isolated human megakaryocytes cultured in serum‐free medium, with or without the c‐Mpl ligand, interleukin‐6 and erythropoietin. When interleukin‐6 was added to the culture medium, the percentage of megakaryocytes displaying proplatelets was approximately 1.5‐fold the control value; whereas, in the presence of the c‐Mpl ligand, the percentage of megakaryocytes displaying proplatelets decreased in a dose‐dependent manner and did not increase compared to control values at any dose tested. However, the viability of megakaryocytes after a 4 d culture in the presence of the c‐Mpl ligand was significantly higher than that of the cells cultured without it. The c‐Mpl ligand did not stimulate the proplatelet formation in megakaryocytes in vitro

Reappraisal of the clinical significance of CD7 expression in association with cytogenetics in de novo acute myeloid leukaemia

Debate exists over whether CD7 expression indicates an unfavourable prognosis in de novo acute myeloid leukaemia (AML). Meanwhile, the type of cytogenetics is a strong prognostic factor in AML. We analysed 256 de novo adult AML cases and found that the proportion of CD7+ cases increased stepwise from the cases with favourable cytogenetics to the cases with intermediate and unfavourable cytogenetics (3 out of 69 cases, 51 out of 140 cases and 25 out of 47 cases respectively, P < 0·0001). CD7‐positivity adversely affected the survival only in the cases with unfavourable cytogenetics (P < 0·03). We recommend that CD7 expression in AML be interpreted in association with the cytogenetics.

Induction therapy consisting of alternating cycles of ranimustine, vincristine, melphalan, dexamethasone and interferon alpha (ROAD-IN) and a randomized comparison of interferon alpha maintenance in multiple myeloma: a co-operative study in Japan.

This pilot study evaluated the efficacy of a new combination chemotherapy with a newly developed nitrosourea derivative ranimustine and evaluated the efficacy of interferon α (IFN‐α) maintenance in previously untreated patients with multiple myeloma (MM). The induction therapy (ROAD‐IN) was a 6‐week regimen consisting of chemotherapy with ranimustine, vincristine (Oncovin), melphalan (Alkeran) and dexamethasone starting on day 1 and IFN‐α, which was administered three times weekly for 3 weeks starting on day 22. This was repeated for three cycles. The responders were subsequently randomized into two groups that received or did not receive IFN‐α as maintenance therapy. Of the 164 patients registered, 161 were evaluated. An objective response to induction therapy was seen in 75% of patients; complete remission (CR) in 38 (24%) and partial remission (PR) in 82 (51%). The median survival for all patients was 3·6 years from registration. The survival of responders (CR + PR) was significantly better than that of non‐responders (median survival 4·3 years vs. 1·4 years; 7‐year survival rate 32% vs. 9%; P < 0·0001). The IFN‐α maintenance did not show any advantage for either response duration or survival. This pilot study demonstrated that a comparatively short period of induction therapy with the ROAD‐IN regimen produced a rather high response rate and a similar survival rate to those achieved with other longer induction regimens, and that good responders to the initial therapy survived significantly longer than non‐responders.

Recombinant human interferon α-2b (rh IFNα-2b) therapy for steroid resistant idiopathic thrombocytopenic purpura (ITP)

The efficacy of recombinant human interferon α‐2b (rh IFNα‐2b) in the treatment of steroid resistant idiopathic thrombocytopenic purpura (ITP) was studied in 50 cases.

A combination chemotherapy with low doses of cytarabine and etoposide for high risk myelodysplastic syndromes and their leukemic stage: A pilot study

Even now, no definitely effective therapy is inducted to high risk myelodysplastic syndromes (MDS) and their leukemic stage (MDS‐AML) except bone marrow transplantation.

Flow cytometric analysis of aberrant antigen expression of blasts using CD45 blast gating for minimal residual disease in acute leukemia and high-risk myelodysplastic syndrome

To evaluate the availability of quantification of blasts with aberrant antigen expression (AAE) using CD45 gating for minimal residual disease (MRD), 15 patients with acute leukemia (AL) and myelodysplastic syndrome (MDS) were studied. In patients with complete remission (CR), the frequency of blasts with AAE (%AAE) by CD45/side scatter (SSC) gating was significantly higher than that by the traditional forward scatter (FSC)/SSC combination (median, 4.1 vs. 0.3%, P<0.0001). We also demonstrated two representative cases, in which leukemia relapse could be predicted before 3 weeks and the early treatment for MRD could be performed for MRD after allogeneic bone marrow transplantation (BMT). These results indicate that this procedure is very useful for the evaluation of the quality of CR.

Ceroid pigment deposition in circulating blood monocytes and T lymphocytes in Hermansky‐Pudlak syndrome: An ultrastructural study

An electron mlcroscoplc study of peripheral leukocytes obtalned from a 39 year old woman with Hermansky‐Pudlak ayndrome was performed. Cerold pigment granules were found within tha lysoaomes in 3.5% of monocytes and 5.4% of lymphocytes. Infrequently, pigment granules were also found in the parallel tubular arrays of lymphocytes. The lymphocytes contalning ceroid pigment granules were confirmed to be T cells by immunoelectron microscopy. It was speculated that intralysosomal accumulation of ceroid pigment granules in Hermansky‐Pudlak syndrome may be due to lysosomal dysfunction.

Effects of C-Mpl Ligand on Cytoplasmic Maturation of Murine Megakaryocytes and on Platelet Production

To test the hypothesis that the c-mpl ligand is not a primary factor in thromb-ocytopoiesis, we investigated the biological effects of recombinant human (rh) c-mpl ligand on differentiation of murine progenitor cells and on maturation of the cultured murine megakaryocytes under serum-free conditions on the basis of ploidy distribution, megakaryocyte/platelet-specific surface antigen CD 61 [glycoprotein (GP) IIIa], and cytoplasmic acetylcholinesterase (AchE) expression in vitro. In addition, we studied the effect of c-mpl ligand on proplatelet formation (PPF) by murine mature megakaryocytes. AchE was less strongly expressed in cultured megakaryocytic cells stimulated by c-mpl ligand than in those stimulated by recombinant murine (rm) IL-3 + rh IL-6 during the differentiation of progenitor cells. Less CD 61 was expressed by c-mpl ligand during both the differentiation of progenitor cells and the maturation of megakaryocytes compared with that by rm IL-3 + rh IL-6. Endomitosis, however, was more stimulated by c-mpl ligand than by rm IL-3 + rh IL-6 under both conditions. Furthermore, PPF of mature megakaryocytes was not stimulated by c-mpl ligand. These results indicate that c-mpl ligand stimulates the nuclear development of megakaryocytic cells but that it does not stimulate cytoplasmic maturation and PPF as much as IL-6. These data strongly suggest that c-mpl ligand is not a primary factor in platelet production.

Multiple red blood cell antibodies produced by donor B lymphocytes after ABO-matched allogeneic bone marrow transplantation.

A 50-year-old man with AML[M2,t(8;21)] underwent BMT from his younger sister. At that time, he had no unexpected antibody and his blood type was O(+), CcDEe. The type of Kidd was not examined. The donors blood type was O(+), CCDee, Jk(a+b-). One year after the BMT, the patients blood type had changed to that of the donors and anti-E antibody was detected. Despite the use of platelet concentrates (PCs) only, anti-c antibody was later identified. We conclude that there is a need to check red cell antibodies at regular intervals, even when using PCs only, for earlier detection of unexpected antibodies after BMT.

Effects of Urinary Extracts from Patients with Idiopathic Thrombocytopenic Purpura or Aplastic Anemia on Rodent Platelet Production and Megakaryocytopoiesis

Urinary extracts from idiopathic thrombocytopenic purpura (ITP) patients, aplastic anemia (AA) patients and normal subjects were investigated for their effects on in vivo platelet production, and both in vitro and in vivo megakaryocytopoiesis in rodents. Daily intraperitoneal injection of 1.2 absorbance units (AU, A278) of urinary protein for three consecutive days induced statistically significant increases in rat blood platelet numbers. This increase was observed for 1 of 4 ITP urinary extracts and for all 3 AA urinary extracts, and occurred 24 h after the final injection. In vitro levels of megakaryocyte colony-stimulating factor (Meg-CSF) in ITP urinary extracts were similar to those of normal urinary extracts, and were in dramatic contrast to the markedly elevated levels of Meg-CSF in extracts from AA urine. A single intraperitoneal injection of 0.5 AU of AA urinary protein induced a significant increase in spleen-derived megakaryocyte colony-forming cells (CFU-meg) 48 h past injection. In the group injected with ITP urinary extract, CFU-meg levels remained within normal limits. These results provide evidence that urinary extracts of ITP patients do not contain increased levels of Meg-CSF and a factor which directly stimulates in vivo CFU-meg production, and that the decrease in circulating platelet numbers that is characteristic of ITP patients is not a primary in vivo determinant in the elaboration of these factors.