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CEBPA-IGH, a fusion gene of the immunoglobulin heavy-chain locus (IGH) and the CCAAT enhancer-binding protein α (C/EBPα) gene, is recurrently found in B-ALL cases and causes aberrant expression of C/EBPα, a master regulator of granulocyte differentiation, in B cells. Forced expression of C/EBPα in B cells was reported to cause loss of B-cell identity due to the inhibition of Pax5, a master regulator of B-cell differentiation; however, it is not known whether the same mechanism is applicable for B-ALL development by CEBPA-IGH. It is known that a full-length isoform of C/EBPα, p42, promotes myeloid differentiation, whereas its N-terminal truncated isoform, p30, inhibits myeloid differentiation through the inhibition of p42; however, the differential role between p42 and p30 in ALL development has not been clarified. In the present study, we examined the effect of the expression of p42 and p30 in B cells by performing RNA-seq of mRNA from LCL stably transfected with p42 or p30. Unexpectedly, suppression of PAX5 target genes was barely observed. Instead, both isoforms suppressed the target genes of MEF2 family members (MEF2s), other regulators of B-cell differentiation. Similarly, MEF2s target genes rather than PAX5 target genes were suppressed in CEBP-IGH-positive ALL (n = 8) compared with other B-ALL (n = 315). Furthermore, binding of both isoforms to MEF2s target genes and the reduction of surrounding histone acetylation were observed in ChIP-qPCR. Our data suggest that the inhibition of MEF2s by C/EBPα plays a role in the development of CEBPA-IGH-positive ALL and that both isoforms work co-operatively to achieve it., (© 2022 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

We conducted a nationwide questionnaire-based survey in 2019 following 2001, 2007 and 2013 surveys to clarify the real-world management of infection during chemotherapy for acute leukemia in Japan. An online questionnaire was sent through SurveyMonkey ® to member institutions of the Japan Adult Leukemia Study Group in June 2019. The questionnaire consisted of 52 multiple-choice questions covering prophylactic measures, screening and diagnostic tests, empirical antibiotic therapy, antifungal management, the usage of granulocyte-colony stimulating factor, and vaccinations against influenza and pneumococcus during intensive chemotherapy for acute leukemia. Questions associated with antimicrobial stewardship were also included. Usable responses were received from 163 of 218 (74.8%) institutions. Approximately, half (52.2%) of the institutes did not have infectious disease department. As antibiotic prophylaxis, fluoroquinolones (62%) were most commonly used in induction chemotherapy for acute myeloid leukemia. No prophylaxis accounted for 19% of the institutions, which has gradually increased compared to previous surveys. In empirical antibiotic therapy for febrile neutropenia, monotherapy with β-lactam antibiotics was the most commonly used first-line therapy. De-escalation was not considered in 42.2% of the institutions. In conclusion, this study clarified the real-world management of infection during intensive chemotherapy for acute leukemia in 2019 and raised future issues in Japan.

To develop gene-modified T-cell-based antileukemia adoptive immunotherapy, concomitant administration of CD4(+) and CD8(+) T cells that have been gene modified using identical HLA class I-restricted leukemia antigen-specific T-cell receptor (TCR) gene transfer has not yet been fully investigated. Here, using CD4(+) and CD8(+) T cells that had been gene modified with a retroviral vector expressing HLA-A*24:02-restricted and Wilms' tumor 1 (WT1)-specific TCR-α/β genes and siRNAs for endogenous TCRs (WT1-siTCR/CD4(+) T cells and WT1-siTCR/CD8(+) T cells), we examined the utility of this strategy. WT1-siTCR/CD4(+) T cells sufficiently recognized leukemia cells in an HLA class I-restricted manner and provided target-specific Th1 help for WT1-siTCR/CD8(+) T cells. By using a xenografted mouse model, we found that WT1-siTCR/CD4(+) T cells migrated to leukemia sites and subsequently attracted WT1-siTCR/CD8(+) T cells via chemotaxis. Therapy-oriented experiments revealed effective enhancement of leukemia suppression mediated by concomitant administration of WT1-siTCR/CD4(+) T cells and WT1-siTCR/CD8(+) T cells. Importantly, this augmented efficacy in the presence of WT1-siTCR/CD4(+) T cells was correlated with longer survival and enhanced formation of memory T cells by WT1-siTCR/CD8(+) T cells. Collectively, our experimental findings strongly suggest that this strategy would be clinically advantageous for the treatment of human leukemia.

A marked increase in leukemia risks was the first and most striking late effect of radiation exposure seen among the Hiroshima and Nagasaki atomic bomb survivors. This article presents analyses of radiation effects on leukemia, lymphoma and multiple myeloma incidence in the Life Span Study cohort of atomic bomb survivors updated 14 years since the last comprehensive report on these malignancies. These analyses make use of tumor- and leukemia-registry based incidence data on 113,011 cohort members with 3.6 million person-years of follow-up from late 1950 through the end of 2001. In addition to a detailed analysis of the excess risk for all leukemias other than chronic lymphocytic leukemia or adult T-cell leukemia (neither of which appear to be radiation-related), we present results for the major hematopoietic malignancy types: acute lymphoblastic leukemia, chronic lymphocytic leukemia, acute myeloid leukemia, chronic myeloid leukemia, adult T-cell leukemia, Hodgkin and non-Hodgkin lymphoma and multiple myeloma. Poisson regression methods were used to characterize the shape of the radiation dose-response relationship and, to the extent the data allowed, to investigate variation in the excess risks with gender, attained age, exposure age and time since exposure. In contrast to the previous report that focused on describing excess absolute rates, we considered both excess absolute rate (EAR) and excess relative risk (ERR) models and found that ERR models can often provide equivalent and sometimes more parsimonious descriptions of the excess risk than EAR models. The leukemia results indicated that there was a nonlinear dose response for leukemias other than chronic lymphocytic leukemia or adult T-cell leukemia, which varied markedly with time and age at exposure, with much of the evidence for this nonlinearity arising from the acute myeloid leukemia risks. Although the leukemia excess risks generally declined with attained age or time since exposure, there was evidence that the radiation-associated excess leukemia risks, especially for acute myeloid leukemia, had persisted throughout the follow-up period out to 55 years after the bombings. As in earlier analyses, there was a weak suggestion of a radiation dose response for non-Hodgkin lymphoma among men, with no indication of such an effect among women. There was no evidence of radiation-associated excess risks for either Hodgkin lymphoma or multiple myeloma.

To identify oncogenes in leukemias, we performed large-scale resequencing of the leukemia genome using DNA sequence arrays that determine approximately 9 Mbp of sequence corresponding to the exons or exon-intron boundaries of 5648 protein-coding genes. Hybridization of genomic DNA from CD34-positive blasts of acute myeloid leukemia (n=19) or myeloproliferative disorder (n=1) with the arrays identified 9148 nonsynonymous nucleotide changes. Subsequent analysis showed that most of these changes were also present in the genomic DNA of the paired controls, with 11 somatic changes identified only in the leukemic blasts. One of these latter changes results in a Met-to-Ile substitution at amino-acid position 511 of Janus kinase 3 (JAK3), and the JAK3(M511I) protein exhibited transforming potential both in vitro and in vivo. Further screening for JAK3 mutations showed novel and known transforming changes in a total of 9 out of 286 cases of leukemia. Our experiments also showed a somatic change responsible for an Arg-to-His substitution at amino-acid position 882 of DNA methyltransferase 3A, which resulted in a loss of DNA methylation activity of >50%. Our data have thus shown a unique profile of gene mutations in human leukemia.

For relevant imatinib therapy against Philadelphia (Ph)-positive leukemias, it is essential to monitor mutations in the chimerical bcr-abl tyrosine kinase domain (TKD). However, there is no universally acceptable consensus on how to efficiently identify mutations in the target TKD. Recently, high-resolution melting (HRM) technology was developed, which allows gene scanning using an inexpensive generic heteroduplex-detecting dsDNA-binding dye. This study aimed to validate the introduction of HRM in a practical clinical setting for screening of mutations in sporadic sites of the chimerical bcr-abl TKD. All chimerical and wild-type abl TKD regions selectively amplified were used for HRM assays and direct sequencing. The HRM test had approximately 5-90% detection sensitivity for mutations. In contrast to mixture samples with mutant and wild-type cells, all mutant cell samples had indeterminate melting curves equivalent to those of the wild-type due to formation of only a homodulex. This issue was improved by the addition of exogenous wild-type DNA after PCR. Subsequently, HRM results gave a high accordance rate of 97.8% (44/45 samples) compared to the sequencing data. The discordant results in one appear to be due to unsuccessful amplification. Thus, HRM may be considered to be suitable for reliable scanning of mutations in the chimerical abl TKD in a clinical setting.

Myeloperoxidase (MPO), a pivotal lineage marker for acute myeloid leukemia (AML), has been also shown to have a prognostic value: a high percentage of MPO-positive blasts correlates to favorable prognosis. To understand the relationship between the expression of MPO in leukemia cells and the response to chemotherapeutic agents, we established MPO-expressing K562 leukemia cell lines and then treated them with cytosine arabinocide (AraC). Cells expressing wild-type MPO, but not mutant MPO that could not mature, died earlier of apoptosis than control K562 cells. Reactive oxygen species (ROS) were generated more in leukemia cells expressing MPO, and the generation was abrogated by MPO inhibitors or antioxidants. Tyrosine nitration of cellular protein also increased more in MPO-expressing K562 cells than control cells after treatment with AraC. In clinical samples, CD34-positive AML cells from high-MPO cases showed a tendency to be sensitive to AraC in the colony-formation assay, and the generation of ROS and the nitration of protein were observed only when the percentage of MPO-expressing cells was high. These data suggest that MPO enhances the chemosensitivity of AML through the generation of ROS and the nitration of proteins.

Acute graft-versus-host disease (GVHD) increases post-transplant mortality and morbidity, but exerts a potent graft-versus-leukemia (GVL) effect. To clarify the impact of GVHD on outcome after transplant in aggressive diseases, patients with acute myeloid or lymphoblastic leukemia (AML, n = 366 or ALL, n = 255) in nonremission states, or chronic myelogenous leukemia (CML, n = 180) in accelerated phase (AP) or blastic crisis (BC), who received allogeneic hematopoietic stem cell transplantation (HSCT) from a related donor between 1991 and 2000, were analyzed. Significant improvement in overall and disease-free survival (DFS) was detected with grade I acute GVHD in AML (P = 0.0002 for overall survival and 0.0009 for DFS, respectively) and in CML (P = 0.0256 and 0.0366, respectively), while the trend towards improved survival was observed in ALL. Relapse rate was lower in grade I acute GVHD than in grade II in all three diseases, suggesting that treatment for grade II GVHD may compromise the GVL effect associated with GVHD. Chronic GVHD was found to suppress relapse in CML and ALL, but not in AML, although no improvement in survival was observed in any disease category. Our results suggest that treatment for grade II acute GVHD may need to be attenuated in transplant for refractory leukemias.

The recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT) often develop acute graft-versus-host disease (aGVHD), which is closely related to morbidity and mortality. However, the essential part of the immune responses elicited in aGVHD remains largely unknown. We attempt to determine if peripheral blood dendritic cells (PBDCs) are altered in aGVHD, and find that the number of PBDCs (both myeloid and lymphoid DCs) is significantly decreased. Immunohistochemical staining of the biopsied skin from patients with aGVHD demonstrates that a number of fascin(+) cells with dendritic projections infiltrate the dermis of the skin. Based on these findings, we hypothesize that the PBDCs are recruited to the affected tissues and may thus play important roles in immune responses elicited in aGVHD.

In a retrospective study to evaluate the efficacy of isoniazid (INH) for the prevention of tuberculosis, we studied 1760 patients with hematological malignancies over a twenty-year period (1970-1989). 759 patients received oral INH, most of all received 400 mg per day. Only one (0.1%) of the patients receiving INH developed tuberculosis, whereas nine (0.9%) of the 1001 patients who did not receive INH developed tuberculosis (p less than 0.05). We found that INH was very effective in the prevention of tuberculosis in patients with hematological malignancies, and was well tolerated.

The article presents a study that determines the role of double-stranded RNA-dependent protein kinase and antisense viral RNA in activation of adult T-cell leukemia (ATL) or lymphoma cells. Overview of the background the study that searches for candidate RNAs derived from the genome and MT-1 cells is provided. The result of the study which suggests that the antisense RNA was involved in the constitutive activation of ATL cells is offered.

The efficacy of unrelated transplantation for patients with ALL who lack an HLA-matched sibling remains unclear. We performed a decision analysis to determine the efficacy of myeloablative transplantation from a genetically HLA-A, -B, -DRB1 allele-matched unrelated donor for patients with Ph chromosome-negative ALL aged 21-54 years. The transition probabilities were estimated from the Japan Adult Leukemia Study Group studies (ALL93; n=80, ALL97; n=82), and the Japan Marrow Donor Program database (transplantation in first CR (CR1): n=177). The primary outcome measure was the 10-year survival probability with or without quality of life (QOL) adjustment. Subgroup analyses were performed according to risk stratification based on the WBC count and cytogenetics, and according to age stratification. In all patients, unrelated transplantation in CR1 was shown to be superior in analyses both with and without QOL adjustment (40.8 vs 28.4% and 43.9 vs 29.0%, respectively). A similar tendency was observed in all subgroups. The decision model was sensitive to the probability of leukemia-free survival following chemotherapy and the probability of survival after transplantation in standard-risk and higher-aged patients. Unrelated transplantation in CR1 improves the long-term survival probability in patients who lack an HLA-matched sibling. However, recent improvements in treatment strategies may change this result. [ABSTRACT FROM AUTHOR]

Adult T-cell leukemia/lymphoma (ATLL), an aggressive neoplasm etiologically associated with human T-lymphotropic virus type-1 (HTLV-1), is resistant to treatment. In this study, we examined the effects of a new inhibitor of deacetylase enzymes, LBH589, on ATLL cells. LBH589 effectively induced apoptosis in ATLL-related cell lines and primary ATLL cells and reduced the size of tumors inoculated in SCID mice. Analyses, including with a DNA microarray, revealed that neither death receptors nor p53 pathways contributed to the apoptosis. Instead, LBH589 activated an intrinsic pathway through the activation of caspase-2. Furthermore, small interfering RNA experiments targeting caspase-2, caspase-9, RAIDD, p53-induced protein with a death domain (PIDD) and RIPK1 (RIP) indicated that activation of RAIDD is crucial and an event initiating this pathway. In addition, LBH589 caused a marked decrease in levels of factors involved in ATLL cell proliferation and invasion such as CCR4, IL-2R and HTLV-1 HBZ-SI, a spliced form of the HTLV-1 basic zipper factor HBZ. In conclusion, we showed that LBH589 is a strong inducer of apoptosis in ATLL cells and uncovered a novel apoptotic pathway initiated by activation of RAIDD. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can provide long-term remission for patients with adult T-cell leukemia/lymphoma (ATLL) caused by human retrovirus, human T-lymphocyte virus (HTLV-1). To understand how HTLV-1-positive cells including ATLL cells were suppressed by allo-HSCT, we examined HTLV-1 provirus load and residual ATLL cells in peripheral blood of transplant recipients using PCR-based tests. We found that the copy number of HTLV-1 genome, called provirus, became very small in number after allo-HSCT; however, in most cases, provirus did not disappear even among long-term survivors. Tumor-specific PCR tests demonstrated that most of HTLV-1-positive cells that remained long after transplantation were not primary ATLL cells but donor-derived HTLV-1-positive cells. We also found a case having very low amount of residual disease in peripheral blood even long after transplantation. There was only one recipient in whom we failed to show the presence of HTLV-1 genome and antibody against HTLV-1 even with an extensive search, which strongly suggested the elimination of HTLV-1 after allo-HSCT. These results demonstrated that after allo-HSCT the small amount of residual HTLV-1-positive cells were heterogeneous in origin and that long-term disease control for ATLL could be obtained without the complete elimination of HTLV-1.Leukemia (2007) 21, 1212–1217. doi:10.1038/sj.leu.2404678; published online 5 April 2007 [ABSTRACT FROM AUTHOR]

Adult T-cell leukemia/lymphoma (ATLL) is a distinct peripheral T-cell neoplasm that is highly resistant to chemotherapy. Several groups, including ours, have reported encouraging results of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with ATLL. To confirm our previous report and to establish the basis for a phase II clinical study, we analyzed 40 allo-HSCT for acute and lymphoma types of ATLL in seven institutions in Japan between 1997 and 2002. All evaluable cases entered complete remission (CR) after allo-HSCT and the median survival time was 9.6 months for all patients. The estimated 3-year overall and relapse-free survival, and disease relapse were 45.3, 33.8 and 39.3%, respectively. Among 10 cases with ATLL relapse, five cases achieved CR again: three by the reduction or cessation of immunosuppressive agents, which suggested a graft-versus-ATLL (GvATLL) effect. However, univariate or multivariate analysis did not show any benefit of graft-versus-host disease (GVHD) on the prevention of relapse. These results suggested that allo-HSCT was effective for some patients with aggressive ATLL, and that the GvATLL effect could be achieved even without GVHD. A new phase II trial to test the efficacy of allo-HSCT for ATLL is warranted.Leukemia (2005) 19, 829-834. doi:10.1038/sj.leu.2403682 Published online 3 March 2005 [ABSTRACT FROM AUTHOR]

Adult T cell leukemia/lymphoma (ATL) is a poor prognosis T cell malignancy. In order to improve the outcome, we employed allogeneic stem cell transplantation (allo-SCT) for ATL in 10 patients, nine of whom were from HLA-identical siblings and one from an unrelated donor. Conditioning regimens varied among the patients except that all received total body irradiation. The patients tolerated the regimens well with mild, if any toxicity, and engraftment occurred in all cases. Median leukemia-free survival after allo-SCT was 17.5+ months (range 3.7–34.4+). Six of the 10 patients developed acute GVHD (one case each with grade I, III or IV, and three cases with grade II) and three patients developed extensive chronic GVHD. Four patients died after allo-SCT during the study period from either acute GVHD (grade IV), pneumonitis, gastrointestinal bleeding or renal insufficiency. Two of the 10 cases with no symptoms of GVHD relapsed with clinical ATL. These results strongly suggest that allo-SCT may improve the survival in ATL if a controlled degree of GVHD develops. Bone Marrow Transplantation (2001) 27, 15–20. [ABSTRACT FROM AUTHOR]

We studied both serum-free colony-forming unit-megakaryocyte (CFU-meg) numbers and serum thrombopoietin (TPO) levels in 14 patients with aplastic anemia (AA), 37 patients with myelodysplastic syndromes (MDS) and 23 patients with idiopathic thrombocytopenic purpura (ITP) to assess thrombopoiesis in these thrombocytopenic disorders. The mean CFU-meg numbers were lower in AA and MDS patients (10.7 +/- 11.4 and 42.3 +/- 58.5/10(5) BMLD cells) than in healthy controls (103.1 +/- 57.3/10(5) BMLD cells) (P < 0.0001 and P= 0.0053, respectively), although they were distributed variably in MDS. ITP patients showed higher CFU-meg numbers (223.2 +/- 143.5/10(5) BMLD cells) (P= 0.017). The mean TPO concentrations were higher in both AA (986.8 +/- 500.8 pg/ml) and MDS patients (838.2 +/- 639.1 pg/ml) than in healthy controls (80.7 +/- 38.8 pg/ml) (P < 0.0001), although they were distributed from high to low in MDS. ITP patients showed a slight elevation of TPO (123.1 +/- 55.3 pg/ml) P = 0.0106). The TPO levels was inversely correlated to both platelet counts and CFU-meg numbers (correlative coefficient (CC): -0.719 and -0.682, P < 0.0001) in AA, but not in ITP. In MDS, the inverse correlation to TPO was stronger in CFU-meg (CC: -0.678, P < 0.0001) than in platelet counts (CC: -0.538, P = 0.0014), suggesting that CFU-meg plays an important role in regulating TPO production in this heterogenous disorder. CFU-meg and TPO may provide useful information for understanding thrombopoiesis of MDS, especially for application of TPO. [ABSTRACT FROM AUTHOR]