Tomohiro Sugawara

Decreased expression of transcription factor GATA-2 in haematopoietic stem cells in patients with aplastic anaemia

Aplastic anaemia is characterized by reduced haematopoiesis resulting in pancytopenia. It has been speculated that there is an injury in haematopoietic stem cells in the bone marrow; however, the precise nature of the injury has not been elucidated. In this study, the levels of expression of mRNAs for three transcription factors, GATA‐2, SCL and AML1, which function in the early stages of haematopoiesis, were examined by quantitative polymerase chain reaction in patients with aplastic anaemia, idiopathic thrombocytopenic purpura (ITP) and normal subjects. Among these factors, expression of GATA‐2 mRNA in purified CD34‐positive cells was markedly decreased in aplastic anaemia compared with that in ITP and in normal subjects. The expression levels of SCL and AML1 mRNA in CD34‐positive cells in aplastic anaemia were not different from those in normal subjects. When the expression of GATA‐2 protein in CD34‐positive cells was examined by immunocytochemical analysis, the percentage of GATA‐2‐positive cells in aplastic anaemia was lower than that in normal subjects. These findings strongly suggest that there is an aberrant expression of transcription factors in stem cells in aplastic anaemia, which may be responsible for the development of the disease.

T cell-mediated inhibition of erythropoiesis in aplastic anaemia: the possible role of IFN-γ and TNF-α

Summary. The inhibitory activity of T cells on autologous erythroid colony‐forming units (CFU‐E) (T cell inhibitory activity) in patients with aplastic anaemia (AA) was investigated. In 11 (32·4%) out of 34 AA cases, T cell inhibition on autologous CFU‐E growth was greater than that in normal individuals. In order to evaluate the mechanism of this inhibitory activity, T cell surface markers, interferon (IFN) production in peripheral blood mononuclear cell (PBMNC) liquid culture, and cytokine levels such as IFN and tumour necrosis factor‐α (TNF‐α) in CFU‐E clot cocultured with T cells, were measured in a portion of the patients. In five patients investigated for IFN production in PBMNC liquid culture, all produced statistically more IFN activity than normal individuals under phytohaemagglutinin (PHA‐P) stimulation (P<0·01) with no relation to T cell inhibitory activity. In only one patient whose T cells displayed increased CD8 and HLA‐DR antigen (CD8+HLA‐DR+) and inhibitory activity, a significant amount of IFN‐γ was observed in CFU‐E clot cocultured with T cells, and the addition of anti‐IFN‐γ antibody to the coculture resulted in recovered CFU‐E colony growth. These results suggest that IFN‐γ production by T cells may explain, at least in part, the pathogenesis of haematopoietic defects in AA. In other patients however, T cell inhibitory activity neither correlated to the T cell subpopulations (CD4+/CD8+, CD8+HLA‐DR+), IFN production in PBMNC liquid culture, nor to IFN and TNF‐α levels in CFU‐E clot culture. The roles played by cytokines other than IFN and TNF‐α on haematopoietic precursor cells require further evaluation in a larger sample of patients with AA.

A new complex translocation t(5;17;15)(q11;q21;q22) in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is associated with the t(15;17)(q22;q21) translocation which causes the fusion of the retinoic acid alpha gene (RARA) on 17q21 to the promyelocytic leukemia gene (PML) on 15q22. The two chimeric genes, PML/RARA and RARA/PML, are thought to play a role in leukemogenesis. A small proportion of patients with APL have complex or simple variants of this translocation. We report the case of a 22-year-old woman with APL carrying a complex variant translocation t(5;17;15)(q11;q12;q22) confirmed by G-banding, reverse transcription polymerase chain reaction (RT-PCR), fluorescence in situ hybridization(FISH), and spectral karyotyping analysis (SKY). The patient achieved complete remission with all-trans retinoic acid treatment and chemotherapy. These results illustrate the usefulness of combined analysis consisting of G-banding, RT-PCR, FISH, and SKY methods to identify the PML/RARA fusion gene in cases with variant t(15;17).

A retrospective analysis of bortezomib therapy for Japanese patients with relapsed or refractory multiple myeloma: β2-microglobulin associated with time to progression

Bortezomib is approved for the treatment of patients with relapsed or refractory multiple myeloma (MM), but only a few clinical studies for Japanese patients who were treated with bortezomib have been reported. We retrospectively analyzed 40 patients with relapsed or refractory MM who have received bortezomib at three collaborating centers in Miyagi prefecture in Japan. All the patients have been received bortezomib in combination with dexamethasone. Responses were determined using International Myeloma Working Group uniform response criteria. The overall response was observed in 30 patients (75%), including very good partial response in 8 patients (20%), and partial response in 22 patients (55%). The median time to disease progression was 8.7 months, and the median overall survival has not been reached. The factors affecting time to disease progression were International Staging System stage, serum β2-microglobulin level, and number of treatment cycles. The most common grade 3 and 4 adverse events were thrombocytopenia (50%), peripheral neuropathy (25%), leukopenia (25%), and herpes zoster infection (25%). Thus, bortezomib is well tolerated and effective for Japanese patients with relapsed or refractory MM. Our results suggest that serum β2-microglobulin level may be a marker of prognosis on bortezomib therapy for patients with relapsed or refractory MM although further studies are needed.

A prospective analysis of clinical efficacy and safety in chronic myeloid leukemia-chronic phase patients with imatinib resistance or intolerance as evaluated using European LeukemiaNet 2013 criteria.

We conducted a phase II study to evaluate the efficacy and safety of dasatinib in Japanese patients with imatinib‐resistant or imatinib‐intolerant chronic myeloid leukemia (CML).

A novel translocation involving chromosomes 2, 9, 14, and 22 in chronic myeloid leukemia

A 46-year-old man with chronic myelogenous leukemia was found to have a new complex translocation. In chronic phase, all of the bone marrow cells had a rearrangement of a t(2;9;14;22) (p21;q34;q32;q11). Southern blot analysis of leukocyte DNA revealed rearrangement of the breakpoint cluster region (bcr) within the 5.8-Kb bcr. The patient eventually died in blast crisis 28 months later. The cytogenetic findings of bone marrow cells showed a 46,XY,t(2;9;14;22)(p21;q34;q32;q11),add(1p),del(3q) karyotype in blast crisis.