Kinuyo Kaneda

Activated human umbilical cord blood dendritic cells kill tumor cells without damaging normal hematological progenitor cells.

Apart from their role as antigen presenting cells, human peripheral blood monocyte and CD34+ cell‐derived dendritic cells (DC), have been demonstrated to exert cytotoxicity against some tumor cells, and their tumoricidal activity can be enhanced by some stimili. However, there have been no reports concerning the tumoricidal activity of human cord blood dendritic cells (CBDC). In this article, we report that human cord blood monocyte‐derived DC acquire the ability to kill hematological tumor cells, after activation with lipopolysaccharide (LPS) or γ‐interferon (IFN‐γ), associated with the enhanced TNF‐α‐related apoptosis‐inducing ligand (TRAIL) expression in CBDC cytoplasm. The CD14‐positive cells collected from cord blood were induced to CBDC in vitro. After activation with IFN‐γ for 12 h, CBDC exhibited cytotoxicity against HL60 and Jurkat cells, while activation with LPS induced cytotoxicity against Daudi and Jurkat cells. However, both LPS‐ and IFN‐γ‐stimulated CBDC showed no cytotoxic activity against normal CD14‐negative cord blood mononuclear cells. The formation of umbilical cord hematopoietic progenitor colonies, identified as burst‐forming unit‐erythroid and colony‐forming unit granulocyte‐macrophage, was not inhibited by stimulated or unstimulated CBDC. IFN‐γ or LPS stimulation enhanced intracellular but not cellular surface TRAIL, and neither intracellular nor cellular surface tumor necrosing factor‐α and Fas Ligand as analyzed by flow cytometry. Our results show that activated CBDC can serve as cytotoxic cells against hematological tumor cells without damaging the normal hematopoietic progenitor cells. (Cancer Sci 2005; 96: 127–133)

A novel fusion variant of the MORF and CBP genes detected in therapy-related myelodysplastic syndrome with t(10;16)(q22;p13)

Summary. We report a case of therapy‐related myelodysplastic syndrome (t‐MDS) with t(10;16)(q22;p13), in which novel fusion transcripts of the MORF and CBP genes were detected. In one MORF–CBP fusion transcript, exon 15 of the MORF gene was fused in frame with exon 5 of the CBP gene. In a reciprocal CBP–MORF transcript, exon 4 of the CBP gene was fused in frame with exon 16 of the MORF gene. This is the first reported case of t‐MDS associated with t(10;16), and provides molecular evidence that the novel MORF–CBP and/or CBP–MORF fusion protein(s) might play an important role in the development of t‐MDS.

Plasma stromal cell-derived factor-1 during granulocyte colony-stimulating factor-induced peripheral blood stem cell mobilization

Summary:In this report, we examined plasma stromal cell-derived factor-1 levels in normal healthy donors for allogeneic peripheral blood stem cell transplantation (PBSCT) and in patients for autologous PBSCT using an enzyme-linked immunosorbent assay. The average level of plasma stromal cell-derived factor-1 was 2197 pg/ml before granulocyte colony-stimulating factor administration and 1899 pg/ml on day 4, demonstrating a significant decrease in the peripheral blood of healthy donors (P=0.0003). In patients for autologous PBSCT, a significant decrease of plasma stromal cell-derived factor-1 in the peripheral blood was also observed (P=0.0464). However, the physiologic gradient of stromal cell-derived factor-1 between peripheral blood and bone marrow was never inverted in normal healthy donors or in autologous PBSCT patients. Our results suggest that stromal cell-derived factor-1 may not be involved in the granulocyte colony-stimulating factor-induced release of CD34+ cells to the peripheral blood. Further studies of a possible additive effect of granulocyte colony-stimulating factor and stromal cell-derived factor-1 are warranted.

Megakaryoblastic leukemia cell line MOLM-16 derived from minimally differentiated acute leukemia with myeloid/NK precursor phenotype

The megakaryoblastic leukemia cell line MOLM-16 was established at relapse from the peripheral blood of a 77-year-old Japanese woman with minimally differentiated acute myeloid leukemia (AML-M0). Immunophenotyping of the fresh leukemic cells revealed a myeloid/NK precursor phenotype being positive for CD7, CD13, CD33, CD34, and CD56. In addition, megakaryocyte-associated antigens CD41 and CD61 were found to be positive. The established cell line designated MOLM-16 was proliferatively responsive to the treatment with various cytokines including EPO, GM-CSF, IL-3, PIXY-321, and TPO. MOLM-16 revealed characteristics of the megakaryocytic lineage in terms of immunophenotyping being positive for CD9, CD31, CD36, CD41, CD61, CD62P, CD63, CD110, CD151, thrombospondin, von Willebrand factor (vWf), and fibrinogen. Electron microscopic analysis showed positivity for ultrastructural platelet peroxidase in the nuclear envelope. The karyotype analysis of MOLM-16 revealed various numerical and structural abnormalities including t(6;8)(q21;q24.3), t(9;18)(q13;q21) and marker chromosomes. The extensive immunological, cytogenetic and functional characterization of MOLM-16 suggests that this cell line may represent a scientifically significant in vitro model which could facilitate the evaluation of megakaryocytic differentiation.

Can t(8;21) oligoblastic leukemia be called a myelodysplastic syndrome?

Abstract:  The new World Health Organization (WHO) classification of hematologic malignancies has incorporated t(8;21) myelodysplastic syndromes (MDS) according to the French–American–British classification into the category of acute myeloid leukemia (AML) with t(8;21)(q22;q22), while our knowledge about clinicopathological features of t(8;21) oligoblastic leukemia is still limited. We present our experience with 12 patients meeting the FAB diagnostic criteria of MDS and having t(8;21), who were compared to 43 t(8;21) AML patients. The MDS and AML patients shared most hematomorphologic, immunophenotypic, and clinical features, whereas the differences lay along myeloid maturation. The MDS patients had higher percentages of circulating neutrophils and marrow myeloid cells beyond promyelocytes than the AML patients. The incidence of Auer rods in mature neutrophils in MDS was significantly higher than that in AML, and furthermore, the neutrophils in MDS more commonly contain t(8;21) than in AML. Our findings support the rationale for the WHO classification, and future studies on large patient populations should help clarify whether the spontaneous differentiation potential could be actively associated with a hematological manifestation of t(8;21) leukemias.

Successful treatment with cyclosporin A of myelodysplastic syndrome with erythroid hypoplasia associated with t(6;8)(q15;q22)

We report a t(6;8)(q15;q22) in a patient with myelodysplastic syndrome (MDS) with erythroid hypoplasia. The patient was successfully treated with an immunosuppressive treatment with cyclosporin A, while the translocation was repeatedly detected as the sole anomaly with the percentages of positive cells ranging from 5% to 70%. To our knowledge, the t(6:8) has never been described in MDS.

Specificity of polymerase chain reaction-based clonality analysis of immunoglobulin heavy chain gene rearrangement for the detection of bone marrow infiltrate in B-cell lymphoma-associated haemophagocytic syndrome

Summary. As a wide range of disorders underlie haemophagocytic syndrome, a rapid distinction between benign polyclonal and malignant monoclonal lymphoid proliferations is critical. We investigated whether polymerase chain reaction (PCR) amplification of immunoglobulin heavy chain gene rearrangement could efficiently detect clonal B‐cell populations in non‐diagnostic marrow for B‐cell lymphoma‐associated haemophagocytic syndrome (B‐LAHS). On amplifying two DNA samples per biopsy, no reproducible monoclonal PCR result was found in reactive haemophagocytic marrows. In contrast, four out of nine assessable B‐LAHS patients with histomorphologically and immunohistochemically lymphoma‐free bone marrow showed a reproducible monoclonal immunoglobulin heavy chain gene rearrangement. At the molecular level, two B‐LAHS patients had lymphoma‐free marrow as demonstrated by patient‐specific PCR, suggesting that haemophagocytic marrow is not always associated with lymphoma involvement. PCR‐based demonstration of clonal B‐cell populations in marrow would add an extra dimension to B‐LAHS diagnosis.