Kenichi Ishizawa

GATA2 regulates dendritic cell differentiation

Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin(-)Sca-1(+)Kit(+) cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte-related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation.

Causes of macrocytic anemia among 628 patients: mean corpuscular volumes of 114 and 130 fL as critical markers for categorization

There have been no studies on the distribution of causes of macrocytic anemia with respect to mean corpuscular volume (MCV) cutoff values. We retrospectively investigated the causes of macrocytic anemia (MCV ≥100xa0fL) among 628 patients who visited the outpatient hematology clinic in Tohoku University Hospital. To ensure data validity, we also analyzed data from 307 patients in eight other hospitals in the Tohoku district. The leading causes of macrocytic anemia (number of patients, %) were myelodysplastic syndromes (121, 19.3xa0%), suspected bone marrow failure syndromes (BMF; 74, 11.8xa0%), aplastic anemia (51, 8.1xa0%), plasma cell dyscrasia (45, 7.2xa0%), and vitamin B12 deficiency (40, 6.4xa0%) in Tohoku University Hospital. We made three primary findings as follows. First, the most common cause of macrocytic anemia is BMF. Second, lymphoid and solid malignancies are also common causes of macrocytosis. Third, macrocytic anemia may be classified into three groups: Group 1 (megaloblastic anemia and medications), which can exceed MCV 130xa0fL; Group 2 (alcoholism/liver disease, BMF, myeloid malignancy, and hemolytic anemia), which can exceed MCV 114xa0fL; and Group 3 (lymphoid malignancy, chronic renal failure, hypothyroidism, and solid tumors), which does not exceed MCV 114xa0fL. These conclusions were supported by the results from eight other hospitals.

Evaluation of the safety and efficacy of recombinant soluble thrombomodulin for patients with disseminated intravascular coagulation associated with acute leukemia: multicenter prospective study by the Tohoku Hematology Forum

It has been suggested that use of recombinant soluble thrombomodulin (rTM) is superior to conventional drugs in treatment of disseminated intravascular coagulation (DIC) complicating acute leukemia. However, its safety and efficacy have not been fully examined in prospective studies. Here, we performed a multicenter prospective study to examine outcomes of rTM treatment for DIC in patients with acute leukemia. Of 33 patients registered in this study, 13 had acute myeloid leukemia (AML), three had acute lymphoblastic leukemia (ALL), and 17 had acute promyelocytic leukemia (APL). The cumulative rates of DIC resolution at day 7 and day 35 were 56 and 81% in AML/ALL and 53 and 77% in APL, respectively. The median time from the initiation of rTM to DIC resolution was 4xa0days in AML/ALL and 6xa0days in APL patients. Adverse events related to hemorrhage occurred in two AML/ALL patients (13%) and three APL patients (18%). Of these, one AML/ALL patient died with intracranial hemorrhage, and two APL patients died with intracranial hemorrhage and pulmonary hemorrhage. These results suggest that rTM may improve the survival of acute leukemia patients with DIC by inhibiting early death related to hemorrhagic events, as reported previously.

Impact of TET2 deficiency on iron metabolism in erythroblasts

Sideroblastic anemia is characterized by the presence of ring sideroblasts (RSs), which are caused by iron accumulation in the mitochondria of erythroblasts and are present in both the acquired and congenital forms of the disease. However, the mechanism leading to RS formationxa0remains elusive. Acquired sideroblastic anemia is usually observed in myelodysplastic syndrome (MDS). Because a subset of MDS harbors a somatic mutation of TET2, it may be involved in iron metabolism and/or heme biosynthesis in erythroblasts. Tet2 knockdown (Tet2trap) induced exhibited mild normocytic anemia and elevated serum ferritin levels in 4-month-old mice. Although typical RSs were not observed, increased mitochondrial ferritin (FTMT) amounts were observed in the erythroblasts of Tet2-knockdown mice. Quantitative real-time polymerase chain reaction demonstrated significant dysregulation of genes involved in iron and heme metabolism, including Hmox1, Fech, Abcb7, and Sf3b1 downregulation. After the identification of a cytosine-guanine island in the promoters of Fech, Abcb7, and Sf3b1, we evaluated DNA methylation status and found significantly higher methylation levels at the CpG sites in the erythroblasts of Tet2-knockdown mice. Furthermore, Tet2 knockdown in erythroblasts resulted in decreased heme concentration and accumulation of FTMT. Therefore, TET2 plays a role in the iron and heme metabolism in erythroblasts.

Epidemiological and clinical features of adult T-cell leukemia-lymphoma in Japan, 2010-2011: A nationwide survey

Adult T‐cell leukemia–lymphoma (ATL) is a mature T‐cell malignancy associated with human T‐cell leukemia virus type 1 (HTLV‐1) infection. Japan is the most endemic country for HTLV‐1 and ATL in the world. Recent nationwide studies of Japanese blood donors reported that HTLV‐1 carriers spread from endemic areas to non‐endemic areas. Therefore, the latest information on nationwide epidemiological and clinical data for ATL is necessary to guide clinical practice. We undertook a multicenter, hospital‐based survey of newly diagnosed ATL patients from 2010 to 2011. A total of 996 patients with ATL were registered from 126 hospitals across Japan. Of those, 922 (487 men and 435 women) were included in the analysis. The median age at diagnosis was 68 years (interquartile range, 60–75 years). Overall, 67.2% of ATL was diagnosed in the Kyushu–Okinawa area. The most common subtype was acute (49.5%), followed by lymphoma (25.7%), chronic (14.2%), and smoldering (10.6%). Lymphoma type was more prevalent in men (60%), whereas chronic was more prevalent in women (60%). Half of patients with lymphoma type were aged over 70 years, whereas one‐third of patients with the chronic type were aged under 60 years. All of these characteristics were different from those of the previous nationwide surveys in the 1980s and 1990s. This survey clarified that half of current patients with ATL are aged over 68 years who were unable to receive intensive cytotoxic therapies. New less toxic agents for aged patients and further strategies to prevent the development of ATL from HTLV‐1 carrier status are needed.

High Serum Adiponectin Level Is a Risk Factor for Anemia in Japanese Men: A Prospective Observational Study of 1,029 Japanese Subjects.

Erythroid abnormalities including anemia and polycythemia are often observed in the general clinical setting. Because recent studies reported that adiponectin negatively affects hematopoiesis, we performed a prospective observational study to assess the relationship between anemia and adiponectin, as well as other parameters, in 1029 Japanese subjects (477 men and 552 women) 40 years of age and older. Body measurements, blood tests, and nutrition intake studies were performed at baseline, and 5 to 7 years later (follow-up). Hemoglobin (Hb) and hematocrit (Hct) levels in men with high serum adiponectin levels were lower at follow-up than at baseline. Multiple regression analysis showed that age, body mass index, adiponectin, and glutamic-pyruvic transaminase were significantly associated with erythroid-related variables (red blood cells, Hb, and Hct) in both men and women (P <0.05). In a logistic regression analysis, adiponectin, fasting blood glucose, and β-natriuretic peptide were significant risk factors for anemia in men, and blood urea nitrogen and amylase were significant risk factors in women. Physical features and nutrient intake were not risk factors for anemia. Our study demonstrates, both clinically and epidemiologically, that a high serum adiponectin level decreases the amounts of erythroid-related variables and is a risk factor for anemia in Japanese men.

Lenalidomide and low-dose dexamethasone in Japanese patients with newly diagnosed multiple myeloma: A phase II study

In the FIRST trial (MM‐020), lenalidomide plus low‐dose dexamethasone (Rd) reduced the risk of disease progression or death compared with combination melphalan–prednisone–thalidomide. As the FIRST trial did not include any Japanese patients, the efficacy and safety of continuous treatment with Rd was evaluated in 26 Japanese patients with newly diagnosed multiple myeloma (NDMM) in a single‐arm, multicenter, open‐label phase II trial (MM‐025). Patients received lenalidomide on days 1–21 of each 28‐day cycle, with a starting dose of 25 mg/day (dose adjusted for renal impairment), and 40 mg/day dexamethasone (dose adjusted for age) on days 1, 8, 15 and 22 of each 28‐day cycle until disease progression or discontinuation for any reason. In the efficacy evaluable population, overall response rate was 87.5%, including 29.2% of patients who achieved a complete response/very good partial response. Median durations of response, progression‐free survival and overall survival have not been reached. The most common grade 3–4 adverse events were neutropenia (23%) and anemia (19%). The efficacy and safety of Rd were consistent with data from larger studies, including the FIRST trial, thereby supporting the use of Rd continuous in Japanese patients with NDMM who are ineligible for stem cell transplantation.

Non-biased and complete case registration of lymphoid leukemia and lymphoma for five years: a first representative index of Japan from an epidemiologically stable Miyagi Prefecture

Abstract Previous worldwide epidemiological studies on lymphoid leukemia and/or lymphoma (LL/L) had considerable bias because of difficulty in covering all clinical departments of hospitals in a restricted area (population base). These studies may not have reflected the actual number of newly diagnosed cases (incidence) strictly, or the true LL/L subtype frequencies. We searched all cases of newly diagnosed LL/L in Miyagi Prefecture over a 5-year period, including those that were discovered as LL/L sorely after autopsy. We registered the actual number of 2098 cases in the prefecture and calculated an accurate incidence rate (17.8 per 100,000 persons). Additionally, we identified more realistic and detailed frequencies of LL/L subtypes including the leukemic phase of some lymphomas. As Miyagi Prefecture is an area in which the population dynamics are relatively stable and representative of Japan, the result of our epidemiological study can be used as the first representative index of LL/L for Japan.

Expression of TRPM8 in human reactive lymphoid tissues and mature B‑cell neoplasms

Transient receptor potential melastatin 8 (TRPM8) is a member of the transient receptor potential superfamily of Ca2+ channels. The aim of the present study was to clarify TRPM8 expression in reactive lymphoid tissues and mature B-cell neoplasms. Reactive and neoplastic lymphoid tissues were used to evaluate TRPM8 expression by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). TRPM8+ cells were frequently detected in the follicular light zone and marginal zone of reactive lymphoid tissues. Double immunostaining revealed that TRPM8+ cells co-expressed cluster of differentiation (CD) 38, CD79a, CD138, interferon regulatory factor 4/melanoma associated antigen (mutated) 1, B cell CLL/lymphoma 6 and transmembrane activator and CAML interactor. TRPM8+ neoplastic cells were frequently detected in plasma cell myeloma. The positive band of TRPM8 mRNA was confirmed by RT-PCR in cases of myeloma. The present study is, to the best of our knowledge, the first to demonstrate the expression of TRPM8 in reactive lymphoid tissues and mature B-cell neoplasms, revealing that TRPM8 is frequently expressed in pre-plasmablasts, plasmablasts, plasma cells and mature B-cell lymphomas that are likely to differentiate into plasma cells.

Prognostic analysis according to the 2017 ELN risk stratification by genetics in adult acute myeloid leukemia patients treated in the Japan Adult Leukemia Study Group (JALSG) AML201 study

Many genetic alterations that are associated with the prognosis of acute myeloid leukemia (AML) have been identified, and several risk stratification systems based on the genetic status have been recommended. The European LeukemiaNet (ELN) first proposed the risk stratification system for AML in 2010 (ELN-2010), and recently published the revised system (ELN-2017). We validated the long-term prognosis and clinical characteristics of each ELN-2017 risk category in Japanese adult AML patients who were treated in the Japan Adult Leukemia Study Group (JALSG) AML-201 study. We demonstrated that the 3-risk category system of the ELN-2017 successfully discriminated the overall survival and complete remission rates in our cohort in comparison with the 4-risk category of the ELN-2010. However, there were still genetic categories in which stratification of patients into favorable or intermediate risk categories was controversial; the low allelic ratio of FLT3-ITD was not necessarily associated with a better prognosis in patients with FLT3-ITD, and cytogenetic abnormalities may affect the prognosis in patients with favorable genetic lesions such as NPM1 and CEBPA mutations. As many molecular targeting agents, such as FLT3 inhibitors, have been developed, we must continue to modify the genetic risk stratification system to match the progression of therapeutic strategies.