Epigenetic marks, such as histone modifications or DNA methylation, regulate tissue specific gene expression by affecting the structures and accessibility of chromatin or DNA. Epigenetics, the molecular mechanisms regulating the epigenome, would therefore be critically involved in development and cell differentiation versus proliferation. Histone modifications include methylation, acetylation, phosphorylation and ubiquitination of specific lysine, arginine or serine residues on histone tails, and each modification has its own specific effect on gene expressions. Modification of histones is accomplished by multimeric protein complexes including polycomb and trithorax group proteins. Regulation of DNA methylation is another mechanism of epigenetic regulation, which is achieved by DNA methyltransferase (DNMT) and TET family proteins. Methylation of cysteine residues on DNA generally leads to transcriptional repression, and oxidation of methylated cysteines provides another type of molecular mark on DNA that regulates gene expression. Next generation sequencing of tumor genomes has uncovered recurrent somatic mutations of epigenetic genes such as DNMT3A, TET2, and ASXL1 in hematologic malignancies, showing that epigenetic dysregulation is a critical step leading to the transformation of hematopoietic cells. Rigorous integrated functional analyses of mutated epigenetic genes are currently underway, and are anticipated to lead to the development of novel molecularly targeted therapies for hematologic malignancies.

Hematopoietic stem cells (HSCs) are characterized by their ability to self-renew and differentiate into all blood lineage cells. The fate decisions of HSCs (self-renewal versus differentiation) are made through the process of cell division and are often compared to “birth” and “death”. Stem cells give rise to undifferentiated stem cells (birth) or differentiate into progenitor cells (death). This process is regulated by asymmetric/symmetric divisions of HSCs. It has been proposed that fate determination occurs as a stochastic process and that individual stem cell dynamics are randomly regulated. The behavior of HSCs is known to be regulated by the cell intrinsic factor and extrinsic (microenvironmental) stimuli. Therefore, it is possible that the signals from a specific microenvironment (niche) have the potential to control or modulate stem cell dynamics. This review focuses on the functions of the HSC niche and the application of single cell analysis for understanding the mechanisms underlying the HSC decision-making process.

The leukemia stem cell (LSC) model has received considerable attention in the past 20 years with the identification of rare cell populations expressing stem cell markers in leukemia cell populations. LSCs are thought to be responsible for leukemia initiation, recurrence, and drug resistance, thus being regarded as excellent targets for developing curative therapies. However, several features of LSCs have recently been challenged. It has become increasingly evident that LSC phenotypes vary among patients. Technical variation of xenograft assays also affects the results, with a trend for more immunodeficient strains allowing the engraftment of variable LSC populations. Studies using mouse leukemia models have shown that not all leukemias are driven by rare and primitive LSCs, instead containing a large population of LSCs expressing mature markers. In addition, recent insights have highlighted genetic variations as important sources of tumor heterogeneity, indicating that the LSC model may not necessarily explain the heterogeneity observed in some leukemias. Nevertheless, several lines of evidence still suggest the existence of primitive LSCs that are associated with therapeutic resistance and poor prognosis in leukemia. This article summarizes current knowledge of LSCs and discusses the challenges ahead.

The KEAP1-NRF2 system is an inducible molecular mechanism enhancing transcriptions of several cytoprotective genes in response to xenobiotics and oxidative stress. Recently, the KEAP1-NRF2 system has been suggested to directly regulate a portion of the genes related to cell proliferation and differentiation. In hematopoietic cells, NRF2 activation plays a role in maintenance and cell fate determination of hematopoietic stem cells, as well as in maturation processes and homeostasis of megakaryocytes and erythrocytes. In addition, NRF2 activation has been reported to suppress the production and secretion of inflammatory cytokines, thereby exerting anti-inflammatory effects. An NRF2 inducer, BG-12, was recently approved as a drug for multiple sclerosis. In contrast, in acute myeloid leukemia, the leukemia cells reportedly have higher NRF2 mRNA levels that lead to an increase in NRF2 protein abundance, by which these cells acquire high resistance to anticancer drugs. Therefore, both NRF2 activators and inhibitors are promising agents for the development of effective therapies for chronic inflammation and leukemia, respectively.

Genome editing with programmable site-specific nucleases is an emerging technology that enables the manipulation of targeted genes in many organisms and cell lines. Since the development of the CRISPR-Cas9 system in 2012, genome editing has rapidly become an indispensable technology for all life science researchers, applicable in various fields. In this seminar, we will introduce the basics of genome editing and focus on the recent development of genome editing tools and technologies for the modification of various organisms and discuss future directions of the genome editing research field, from basic to medical applications.

Exosomes are membrane vesicles approximately 100 nm in diameter, present in a wide range of body fluids, including blood, cerebrospinal fluid, urine and saliva. Exosomes reflect the physiological state of their cells of origin and cancer cell-derived exosomes carry pathogenic components, such as proteins, messenger RNA (mRNA), microRNA (miRNA), and DNA. Thus, exosomes in body fluids provide a rich source of potential biomarkers. However, the use of exosomes as biomarkers to improve patient care has been limited by their small size and the extensive sample preparation required for their isolation and measurement. In this review, we describe a new liquid biopsy technique designed to sensitively detect disease specific circulating exosomes. We also provide perspectives in translational medicine from the standpoint of diagnosis and therapy.

Most patients with iron deficiency anemia are treated effectively with oral iron preparations. However, a small number of these patients are refractory to such treatments, even when the pathologic condition underlying the anemia is concurrently treated. The pathological basis for this refractoriness can be explained by several factors, including malabsorption of iron, e.g. atrophic gastritis, deficiency of other hematopoietic vitamins or minerals, e.g. vitamin B12 or zinc, other undiagnosed anemic disorders, e.g. renal anemia or hematopoietic diseases, as well as certain hereditary disorders of iron metabolism, e.g. iron refractory iron deficiency anemia (IRIDA) caused by genetic mutation of the TMPRSS6 gene. This review focuses on the diagnosis and pathoetiology of iron deficiency anemia that is refractory to conventional oral iron preparations.

Treatments of aplastic anemia are comprised of supportive therapy and aplastic anemia-specific therapy aimed at restoring hematopoiesis. Supportive therapies include transfusion, G-CSF, and the administration of iron chelation agents, as well as dealing specifically with individual symptoms. Aplastic anemia-specific treatments given with the aim of achieving hematopoietic recovery include immunosuppressive therapy, allogeneic hematopoietic stem cell transplantation, and anabolic hormone therapy. Although transplantation provides complete recovery of hematopoiesis (cure), there is a risk of death due to transplant-related complications. The most effective immunosuppressive therapy is a combination of anti-thymocyte globulin and cyclosporine. This treatment is also effective against the secondary, drug-induced and hepatitis-associated forms of aplastic anemia. In the management of aplastic anemia, a treatment is selected from among these options depending on the disease severity and the age of the individual case. The thrombopoietin receptor agonist eltrombopag appears to be effective and to provide tri-lineage recovery of hematopoiesis in some cases. Indications for its use are expected to expand in Japan.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired GPI deficiency caused by somatic mutation of the PIGA gene in one or several hematopoietic stem cells. Recently, PNH caused by somatic mutation of one allele of the PIGT gene in combination with a germline mutation of the other allele was reported, showing that PIGA is not the only gene responsible for PNH, though other causes are rare. These mutant cells become GPI deficient, expand clonally and differentiate into all of the hematopoietic lineages. When GPI deficient erythrocytes increase in proportion, massive hemolysis occurs due to activated complement attack during infection. As the complement regulatory proteins such as CD59 and DAF are GPI anchored proteins, they are defective on GPI deficient erythrocytes and these abnormal erythrocytes are thereby left unprotected from complement attack. Hemolytic anemia, venous thrombosis, and bone marrow failure are thus the resulting triad of symptoms. Clonal expansion does not occur with PIGA deficiency alone. We hypothesize that PIGA deficient cells acquire a proliferative phenotype via additional gene mutations within the associated environment of bone marrow failure. This hypothesis will be explained by introducing recent reports.

Congenital hemolytic anemia is a group of monogenic diseases presenting with anemia due to increased destruction of circulating erythrocytes. The etiology of inherited anemia accounts for germline mutations of the responsible genes coding for the structural components of erythrocytes and extra-erythrocytes. The erythrocyte abnormalities are classified into three major disorders of red cell membrane defects, hemoglobinopathies, and red cell enzymopathies. The extra-erythrocyte abnormalities, typified by consumption coagulopathy and intravascular hemolysis, include Upshaw-Schulman syndrome and atypical hemolytic uremic syndrome. The clinical manifestations of congenital hemolytic anemia are anemia, jaundice, cholelithiasis and splenomegaly, while the onset mode and severity are both variable. Genetic overlapping of red cell membrane protein disorders, and distinct frequency and mutation spectra differing among races make it difficult to understand this disease entity. On the other hand, genetic modifiers for the phenotype of β-globin diseases provide useful information for selecting the optimal treatment and for long-term management. Recently, next generation sequencing techniques have enabled us to determine the novel causative genes in patients with undiagnosed hemolytic anemias. We herein review the concept and strategy for genetic diagnosis of inherited hemolytic anemias.

Hepcidin is an iron-regulating peptide hormone made in the liver. It controls the delivery of iron to blood plasma from intestinal cells absorbing iron, from erythrocyte-recycling macrophages, and from iron-storing hepatocytes. Hepcidin acts by binding to and inactivating the sole cellular iron exporter, ferroportin, which delivers iron to plasma from all iron-transporting cells. In a classical endocrine feedback system, hepcidin production is stimulated by plasma iron and iron stores. Reflecting a likely role of hepcidin in innate immunity, hepcidin is also induced by inflammation. Increased erythropoietic activity suppresses hepcidin, which leads to increased iron absorption and release of iron from stores, matching iron supply to increased demand. This suppression of hepcidin is in part mediated by erythroferrone, a hormone produced by erythropoietin-stimulated erythroblasts. Hereditary hemochromatosis is caused by hepcidin deficiency or resistance to hepcidin, and hepcidin deficiency also mediates the hyperabsorption of iron in β-thalassemia and other iron-loading anemias. Pathologically increased concentrations of hepcidin are seen in iron-refractory iron deficiency anemia, in anemia of inflammation, and anemia of chronic kidney disease where increased hepcidin limits the availability of iron for erythropoiesis. Its central involvement in a variety of iron disorders makes hepcidin an important target for diagnostic and therapeutic applications.

Current treatment of acute myeloid leukemia (AML) still relies on intensive chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT). AML is a heterogeneous neoplasm characterized by distinct chromosomal and genetic abnormalities. Recent comprehensive gene analyses have highlighted distinct genetic subgroups that are associated with different responses to chemotherapy. Therefore, the molecular landscape of AML is fundamental to the development of novel therapeutic approaches and provides opportunities for individualization of therapy. In addition, the age-related incidence of clonal hematopoiesis is high, affecting nearly 10% of healthy people more than 65 years of age. Clonal hematopoiesis is confirmed by the presence of mutations related to AML including genes involved in DNA methylation, chromatin modification and RNA splicing. In the analysis of gene mutation profiles in secondary AML (s-AML) from myelodysplastic syndromes and myeloproliferative neoplasms, secondary-type gene mutations were identified with >95% specificity in s-AML as compared with de novo AML, including RNA splicing, chromatin modification and cohesion complex genes, and were highly associated with poor responses to chemotherapy as well as TP53 mutation. It is important to identify genetic subgroups at relatively high-risk of relapses who should receive allogeneic HSCT during the first remission. In this review, prognostic stratification for individualized treatment of AML is discussed.

The standard treatment for de novo acute myeloid leukemia (AML) has been established. Although patients with AML achieve complete remission at high rates, the long-term prognosis for such patients remains unsatisfactory. It is therefore necessary to perform hematopoietic stem cell transplantation (HSCT) to improve their outcomes. However, a high rate of transplant-related mortality continues to be a problem associated with allogeneic HSCT. We therefore need to carefully determine the indications for safely performing HSCT based on historical data.

Standard induction chemotherapy regimens achieve complete remission rates of 80% in younger adult patients with acute myeloid leukemia (AML). However, because of disease relapse only 40-50% of patients achieve long-term survival. Five-year survival rates in older patients are only one third of those achieved in younger cases. The adverse prognostic impact of advanced age is attributable to the chemotherapy-resistant nature of the blasts and the limited tolerability these patients have for intensive chemotherapy. For younger patients with relapsed/refractory AML, the therapeutic approach to curing AML is the re-induction of complete remission employing intensive chemotherapy, followed by allogeneic hematopoietic cell transplantation. If this approach is not feasible, less intensive chemotherapy or best supportive care or transplantation without disease remission may be performed. Older patients are unlikely to be candidates for hematopoietic cell transplantation in general. Older patients with newly diagnosed AML of low risk may be treated with intensive chemotherapy, while those with intermediate/high risks may have options including less intensive chemotherapy and best supportive care.

Myeloproliferative neoplasms (MPNs) are chronic hematopoietic stem cell disorders, including polycythemia vera, essential thrombocytosis, and primary myelofibrosis. The JAK2V617F mutation was identified in 2005, followed by the discovery of the JAK2 exon12, MPNW515 mutation, and CALR mutation. About 90% of patients with BCR/ABL negative MPNs have been shown to have one of these driver mutations. In addition, mutations in epigenetic regulators and RNA splicing genes were found to co-exist with driver mutations and to play critical roles in the disease progression of MPNs. Currently, evaluations of these gene mutations are essential for the diagnosis of MPNs, and are also necessary for estimating the clinical course and the risk of disease progression. Guidelines for the management of MPNs were based on the results of large clinical trials. Furthermore, recent advancements in understanding the pathogenesis of MPNs are anticipated to promote the development of MPN-targeted therapies such as JAK2 inhibitors. Clinical trials for patients with PMF and PV have confirmed the efficacies of JAK2 inhibitors.

BCR-ABL tyrosine kinase inhibitor (TKI) has dramatically improved the prognosis of CML patients. Now, one of the most important factors with a marked effect on prognosis in CML patients is having a comorbidity. Recently, cardiovascular events (CVE) have been reported in some clinical trials as a late toxicity of TKI, which might be associated with off-target of TKI, ABL/ARG, PDGFR and VEGFR. Because TKI-associated CVE is one of the potentially lethal adverse events associated with TKI administration, hematologists must practice the “ABCDE steps” for CML patients treated with second generation TKI in collaboration with cardiologists.

The introduction of tyrosine kinase inhibitors (TKIs) has dramatically changed the management of patients with chronic myeloid leukemia (CML). Despite improved outcomes for most CML patients, disease progression from chronic phase (CP) to accelerated phase (AP) or blast phase (BP) occurs in 1-1.5% of cases per year with current TKI therapy. In addition, about 10-15% of newly diagnosed patients present in AP or BP. Even in the TKI era, the prognosis of patients with advanced-phase CML is not satisfactory. Although de novo AP patients who respond optimally to TKI have excellent outcomes, the prognosis of the remaining advanced-phase CML patients treated with TKI remains poor. For advanced-phase CML patients, allogeneic stem cell transplantation (allo-HSCT) is the only curative therapy. Patients eligible for allo-HSCT should first be treated with TKI with or without chemotherapy, in order to obtain reversion to CP, followed promptly by allo-HSCT. At present, the survival rates of patients undergoing allo-HSCT for advanced-phase CML are still disappointing. Prophylactic or preemptive administration of TKIs after allo-HSCT may improve long-term survival. Further investigation to improve the treatment outcomes of patients with advanced-phase CML is warranted.

Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

The WHO classification system of MDS 4^th edition was recently updated. This revision includes nomenclature changes, reflecting the policy of the revision team to emphasize morphological features over cytopenias. Other changes are 1) taking SF3B1 mutation status into account for the definition criteria of MDS-RS (ring sideroblasts), 2) allowing for one additional cytogenetic abnormality (excluding -7/del (7q)) to be diagnosed as ‘MDS with isolated del (5q)’, 3) sub-classifying MDS-U according to the reasons for being included in this category, and 4) changing the diagnostic rules for myeloid neoplasms with erythroid blast predominance. This session also deals with recent topics in hematopoietic stem cell transplantation (HSCT) as an example of progress in therapy for MDS. Although HSCT is the only curative therapy for MDS, high treatment related mortality precludes its applicability especially for elderly patients, for whom demethylating agents are an alternative. Recently, reports on both well-designed retrospective or prospective studies have validated the advantage of HSCT over demethylating agents for patients of comparatively advanced age with higher risk MDS. Optimal intensity of conditioning regimens for HSCT is another controversial topic for which preliminary results of randomized controlled trials have been released and will be introduced in this session.

Diffuse large B-cell lymphoma (DLBCL) accounts for 30-40% of all lymphoma subtypes. More than half of DLBCLs are estimated to arise from extranodal sites, and are called extranodal DLBCLs. Generally, the outcomes of extranodal DLBCL are not different from those of nodal DLBCL. To our knowledge, this report is the first to discuss the concept and the cell of origin of extranodal DLBCL, with the significance of the presence/absence of each involvement site in determining the outcome. Second, the evidence of clinical manifestation and outcomes of several extranodal DLBCLs requiring treatments other than R-CHOP, which is the current standard therapy for this malignancy, are discussed. Most primary central nervous system (CNS) and testicular lymphomas are histologically DLBCLs. Moreover, primary mediastinal and intravascular large B-cell lymphomas are subtypes of DLBCL by definition. Hence, the evidence of high-risk sites for CNS involvement is also described.

Treatment outcomes of malignant lymphoma have improved due to the discovery of novel chemotherapeutic and molecular targeted agents as well as advances in their combination uses. However, the prognosis of T-cell lymphoma remains poorer than that of B-cell lymphomas, and progress is slow. The reasons include their chemotherapeutic resistant nature and the absence of effective antibody agents for T-cell lymphomas. The number of T-cell lymphoma subtypes increased from 21 in the WHO classification 2008 to 29 in the WHO classification 2016. This means that T-cell lymphomas are heterogeneous. T-cell lymphomas can be divided to ALK-positive anaplastic lymphoma (ALCL) with a good prognosis and others with poorer prognoses. ALK-positive ALCL can be successfully treated with CHOP, but the others cannot. P-glycoprotein resistant anthracyclines, etoposide, or hematopoietic stem cell transplantations are increasingly applied to improve outcomes, but no standard treatment approach has yet been established. Regarding relapsed/refractory T-cell lymphoma, many novel agents are currently under development. The treatment outcomes of T-cell lymphoma need to be improved by applying innovative strategies including further novel agents.

This article aims to explain the current status of FDG-PET/CT in malignant lymphoma management by reviewing the new recommendations for evaluation, staging, and response assessment in patients with malignant lymphoma, published as the Lugano Classification in 2014. FDG-PET/CT was formally incorporated into standard staging for FDG-avid lymphoma in this new classification. Nearly all subtypes of malignant lymphoma are FDG-avid. In staging, the increased FDG uptake compatible with lymphoma is considered to represent involvement of lymphoma, regardless of size, and the FDG-avid lesion is potentially a good biopsy target. FDG-PET/CT is more sensitive than bone marrow biopsy in diffuse large B cell lymphoma (DLBCL) and Hodgkin lymphoma (HL). Location, size and FDG uptake, based on a 5 point scale (compared to hepatic uptake and mediastinal blood pool) for the residual lesion, constitute useful information for response assessment. Routine surveillance scans after remission are discouraged, especially for DLBCL and HL. Interim PET is regarded as a promising biomarker for stratifying treatments of malignant lymphoma, although its usefulness remains controversial.

The current standard treatment for diffuse large B-cell lymphoma (DLBCL) is R-CHOP administration. This therapeutic protocol began in the first decade of the 21^st century, based on the results of a randomized trial which compared R-CHOP with a CHOP regimen for elderly patients and showed an approximately 20% survival advantage in the R-CHOP arm. Recent developments of new drugs such as monoclonal antibody and molecularly targeted agents have been remarkable and many such agents have been introduced into clinical practice with high expectations. Nevertheless, the standard regimen for DLBCL has not been renewed for more than 15 years. In this article, we consider the types of investigations which have pointed to the conclusion that the R-CHOP regimen remains the current standard for DLBCL patients. Future perspectives are also discussed.

Outcomes of patients with acute lymphoblastic leukemia (ALL) have improved dramatically with conventional chemotherapy consisting of multiple agents. However, considering the major impact of tyrosine kinase inhibitors in the treatment of Philadelphia chromosome-positive ALL, sensitivities to each chemotherapeutic agent must be appreciated in individual cases to further improve therapeutic outcomes of ALL patients. Recent advances in genome-wide association and comprehensive genetic mutation studies with next-generation sequencing enable the involvement of single nucleotide polymorphisms and acquired genetic mutations in the drug resistance of ALL to be evaluated. Herein, we overview recent findings regarding the mechanisms of drug resistance in ALL. Our observations in a large panel of ALL cell lines are also presented.

TAFRO syndrome is a systemic inflammatory disorder manifesting as thrombocytopenia; anasarca including pleural effusion and ascites; fever; renal insufficiency; and organomegaly including hepatosplenomegaly and lymphadenopathy. Its onset may be acute or sub-acute, but its etiology remains unknown. Although several clinical and pathological characteristics of TAFRO syndrome resemble those of Castleman's disease, other specific features can differentiate between the two. Some patients have been successfully treated with glucocorticoids and/or immunosuppressants including cyclosporin A, tocilizumab and rituximab, whereas others are refractory to treatment, eventually succumbing to the disease. Early and reliable diagnoses and early treatments with appropriate agents are essential to enhancing patient survival. The 2015 updated diagnostic criteria, disease severity classification and treatment strategy for TAFRO syndrome, as formulated by Japanese research teams, are presented herein. Furthermore, clinicopathological data on 28 patients with this condition and similar symptoms (e.g., MCD with serositis and thrombocytopenia) were analyzed retrospectively.

For decades, Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) has been considered the ALL subgroup with the worse outcome. It represents the most frequent genetic subtype of adult ALL and, in the elderly, it accounts for approximately 50% of cases. The introduction of tyrosine kinase inhibitors (TKIs) has led to obtain complete hematologic remissions (CHR) in virtually all patients, to improve disease-free survival and overall survival, and to increase the percentage of patients who can undergo an allogeneic stem cell transplant (allo-SCT). Thus, the current management of adult Ph+ ALL patients is based on the use of a TKI, with or without systemic chemotherapy, followed by an allo-SCT, which still remains the only curative option. Monitoring of minimal residual disease allowed a better stratification of patients, and also enabled to redefine the role of autologous stem cell transplant for patients who do not have a donor or are unfit for an allo-transplant. The main clinical challenges are today represented by the emergence of resistant mutations, particularly the gatekeeper T315I, for which alternative approaches, including novel TKIs and/or therapies based on the combination of TKI with immunotherapeutic strategies, are being considered.

Many patients with Hodgkin lymphoma (HL) can be cured with standard chemotherapy with high long term survival rates¹⁾. Considering the increased risks of various toxicities following therapy, options are evolving towards avoidance of radiation and reduction of therapy duration, with results similar to those currently achieved with improved quality of life^{2, 3)}. However, 20-30% of patients still develop recurrence during or following initial therapy, depending upon what chemotherapy regimen is administered⁴⁾. Investigators have recently described new agents that have produced significant responses in this latter group of patients. In this report, we describe some of these studies, with an emphasis on response and tolerability.

Oncogenic transformation through activation of proliferation generates cellular stress which promotes apoptosis, thereby diminishing the growth advantage of cancerous cells over normal cells. Consequently, many haematological malignancies also harbour aberrations that circumvent apoptosis, with aberrations of TP53 and the BCL2 family being the most common. This educational lecture focuses on current understanding of the role of the intrinsic pathway to apoptosis in lymphoid cancers, its regulation by BCL2 and related proteins, and emerging data on the therapeutic potential of inhibiting BCL2 to induce apoptosis in BCL2-expressing B cell cancers.

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening syndrome of uncontrolled immune activation. It was initially recognized in children, where it occurs primarily as an inherited syndrome related to homozygous null mutations in immune response genes involved in cytotoxic T cell and NK cell function. A minority of pediatric patients develop “secondary” HLH as a consequence of infection or autoimmune disease. In the last 10-15 years, secondary HLH has been increasingly recognized in adults, where it is frequently associated with lymphoid malignancy, infection, or autoimmune disease. This relatively recently recognized diagnosis and the treatment of adult HLH have been largely shaped by observations in pediatric patients. In this brief summary, we focus on the features that distinguish pediatric from adult HLH and discuss the challenges of diagnosis and treatment of this devastating disease.

Autologous stem cell transplantation (ASCT) is known to be superior to conventional chemotherapies and has been established as a standard of care for young patients with multiple myeloma. In the first decade of this century, novel agents such as thalidomide, bortezomib, and lenalidomide became clinically available, and several clinical trials using these drugs as induction therapies, conditioning regimens, and post-transplant consolidation and maintenance therapies have been reported, leading to increasing improvement in treatment results as compared to conventional therapies. Future changes in therapeutic strategies using these novel agents are anticipated to increase the complete response rate and prolong progression free survival and overall survival. This article describes the optimal treatment strategy for ASCT-eligible patients in Japan.

The current therapeutic strategy for multiple myeloma has improved dramatically due to the use of novel agents. In newly diagnosed transplant-ineligible myeloma patients, the standard therapy until the 1990s had long been melphalan and prednisolone (MP), but the recent recommendation is the proteasome inhibitor bortezomib plus MP (MPB), the immunomodulatory drug thalidomide plus MP (MPT), and the thalidomide derivative lenalidomide (LEN)-based regimens such as LEN plus low-dose dexamethasone (Ld) and LEN plus MP (MPL). The overall response rate in patients treated with Ld, MPL, or MPB was reported to be approximately 70%. Achieving complete remission (CR) is important in elderly as well as younger patients. Therefore, MPB administration appears to be the most appropriate initial therapy because the MPB regimen results in high CR rates. However, in elderly patients, especially in those 75 years of age and older and those who are frail or with comorbidities, it is important to balance efficacy and toxicity as well as to maintain quality of life. Furthermore, continuous treatment results in longer survival than a fixed-duration regimen in this population.

In the past decade, previously approved novel agents, such as proteasome inhibitors (bortezomib) and immunomodulatory drugs ([IMiDs]; e.g., lenalidomide), have led to significant improvement in the treatment of multiple myeloma in Japan. However, almost all patients will ultimately relapse, even when they have achieved a deep and prolonged therapeutic response with initial treatment. Next-generation IMiDs (pomalidomide) and deacetylase inhibitors (panobinostat) were approved for use as salvage therapy for refractory and relapsed multiple myeloma [RRMM] within the last year. Long-term chemotherapy could result in the emergence of drug-resistant clones due to “intraclonal heterogeneity” and “clonal evolution by Darwinian selection.” Though some recommendations on the management of RRMM have been detailed, no uniform treatment has yet been established for these patients. Relapse situations are heterogeneous. Therefore, relapse management requires an individual approach based on assessments of patient-, disease-, and treatment-related factors. The primary considerations when selecting an appropriate treatment are patient-related factors such as frailty, comorbidity, disability, quality of life, and the overall goals of care. We hope that these novel agents that appear promising in Japan, such as monoclonal antibodies (e.g., elotuzumab, daratumumab) and next-generation proteasome inhibitors (e.g., carfilzomib, ixazomib) will improve the outcomes of patients with this incurable disease in the near future.

Multiple myeloma (MM) has been diagnosed based on the International Myeloma Working Group (IMWG) diagnostic criteria since 2003. In 2014, the IMWG updated these diagnostic criteria to add three specific biomarkers, i.e., 1) Clonal bone marrow plasma cell percentage ≥60%; 2) Involved: uninvolved serum free light chain ratio ≥100; 3) >1 focal lesion on MRI studies, based on CRAB features (hypercalcemia, renal failure, anemia, and bone lesions). An early diagnosis of MM can be made, allowing timely anti-MM treatment, in patients with the ultra-high-risk smoldering form of this disease. This review focuses on the new IMWG diagnostic criteria for MM and evaluation of patients newly diagnosed with MM.

Despite the major recent strides achieved in myeloma treatment owing to the implementation of new anti-myeloma agents, bone destruction is still a leading cause of deterioration in quality of life (QoL) for affected patients. With improvement of survival, bone management will become more important for maintaining QoL especially in elderly patients; novel treatment modalities with bone anabolic activity are highly anticipated, as a means of restoring bone in bone destructive lesions as well as from the aspect of preventing bone destruction with currently available anti-resorptive agents. Long-term management of myeloma bone disease in the era of these new agents and a perspective on the development of new bone modifying agents will be discussed.

von Willebrand factor (VWF) has two major roles in hemostasis, as a form of molecular glue which functions in platelet plug formation and as a protective transporter for coagulation factor VIII (FVIII). VWF shows a multimeric chain structure composed of 270 kDa subunits containing binding domains for FVIII, platelet and collagens. Biosynthesis, storage, secretion of VWF and the cleavage process by ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type 1 repeats 13) regulating VWF activity have been elucidated. von Willebrand disease (VWD) is an autosomal bleeding disorder, first documented in 1926, caused by quantitative or qualitative deficiency of VWF. The classification and molecular pathogenesis of VWD have been developed during a 90-year period based on clinical laboratory analysis of VWF, and structure-function analysis of mutant VWF with amino acid substitutions (genetic changes). VWF is a unique and very large multifunctional plasma protein, the hemostatic activity of which is dynamically regulated by physiological shear stress in the blood stream.

Heparin-induced thrombocytopenia (HIT) is a pro-thrombotic side effect of heparin therapy caused by HIT antibodies with platelet-activating properties. Recent advances in understanding of spontaneous HIT syndrome, which can occur even without any heparin exposure despite its clinical and serological characteristics being similar to those of HIT, reveal the following HIT clinical features atypical for an immune-mediated disease. Heparin-naïve patients can develop IgG antibodies as early as day 4, as in a secondary immune response. Evidence for an anamnestic response upon heparin re-exposure is lacking. In addition, HIT antibodies are relatively short-lived, unlike those in a secondary immune response. Antigen immunoassays are commonly used worldwide for serological diagnosis of HIT. However, such assays do not indicate whether HIT antibodies have platelet-activating properties, leading to low diagnostic specificity for HIT. The detection of platelet-activating antibodies using a washed platelet activation assay is crucial for making a HIT diagnosis. These atypical clinical and serological features should be carefully considered while appropriately diagnosing HIT, which leads to appropriate therapy such as immediate administration of an alternative anticoagulant for preventing thromboembolic events and re-administration of heparin during surgery involving cardiopulmonary bypass when HIT antibodies are no longer detectable.

The clinical features noted in individuals with disseminated intravascular coagulation (DIC) complicated by hematological malignancies include life threatening hemorrhage that is associated with thrombocytopenia and consumptive deficiency of coagulation factors. Exacerbation of DIC after the initiation of chemotherapy is also related to fatal hemorrhage. The Japanese Society of Thrombosis and Hemostasis recently proposed provisional DIC diagnostic criteria allowing evaluation of hypercoagulable markers such as soluble fibrin and thrombin-antithrombin complex to help physicians to diagnose DIC and initiate treatment in the early phase of coagulopathy. A phase III clinical trial showed that human soluble recombinant thrombomodulin (rTM) more potently improved DIC than unfractionated heparin and was approved for treatment of DIC in 2008 in Japan. rTM exerts anti-inflammatory and cytoprotective actions and may improve clinical outcomes of DIC patients.

In Japan, the media often announce investigator-initiated clinical trials (IIT). However, experts and reliable information remain limited. As most of the physicians involved do not have enough experience with the development of new medical drugs and devices, they need support from a contract research organization (CRO). The author recently managed two rituximab trials, one for immune thrombocytopenia (ITP) and the other for thrombotic thrombocytopenic purpura (TTP). It is hoped that the present lecture will be useful for investigators who are planning new IIT.

General statements have been published regarding the clinical laboratory tests for thrombosis and hemostasis to be used by hematologists who do not specialize in this field. Screening tests for bleeding are bleeding time, capillary fragility test, platelet count, prothrombin time, activated partial thromboplastin time (APTT), fibrinogen, fibrin/fibrinogen degradation products (FDP), and the cross mixing test conducted by measuring APTT. Screening tests for thrombosis and related factors include measurements of FDP, D-dimer, and thrombin-antithrombin complex. To assess thrombotic factors, we should measure antithrombin (AT), protein C, protein S, antiphospholipid antibody, and heparin induced thrombocytopenia antibody. If a congenital thrombotic factor abnormality is suspected, the clinician should examine activities of AT, protein C, protein S, plasminogen, and fibrinogen. Antigen levels of each parameter are also examined, if warranted. The cross mixing test conducted by measuring APTT is useful for differentiating between deficiencies and inhibitor presence.

Platelets are critical for hemostasis and genetic defects involving platelet functions result in symptomatic bleeding of varying severities. In contrast to platelet quantitative disorders, qualitative platelet disorders are relatively rare and are difficult to diagnose, especially in patients with mild bleeding symptoms due to their lack of specificity for platelet dysfunction. In addition, the lack of standard platelet function tests makes it difficult for physicians to clinically distinguish patients from healthy subjects and, on occasion, the cause of bleeding symptoms remains unspecified. Resting platelets in the circulation become activated for thrombus formation at the site of vascular injury. Thrombus formation consists of platelet adhesion, granule secretion, and aggregate formation. An abnormality in any of the steps of thrombus formation has the potential to cause platelet dysfunction and bleeding symptoms. Understanding the mechanism of thrombus formation and the laboratory tests for evaluation of each step is important for properly diagnosing platelet function disorders.

Allogeneic hematopoietic stem cell transplantation remains the cornerstone of curative therapy for haematological malignancies but is limited by graft-versus-host disease (GVHD), both acute and chronic. Exciting new approaches have been developed to prevent GVHD in the last 5 years and some have already successfully translated into the clinic. These strategies have been born from new model systems that allow the dissection of alloantigen specific responses that have in turn informed new disease paradigms. In this review, we discuss these recent insights into the biology of GVHD that appear to be highly predictive for improved clinical outcomes.

Methylprednisolone administered at a dose of 2 mg/kg is a standard first-line systemic therapy for grade II to IV acute graft-versus-host disease (GVHD). Lower dose methylprednisolone or prednisone, at doses of 0.5-1.0 mg/kg, is also accepted as a first-line therapy for mild acute GVHD. Response rates of grade II to IV acute GVHD to systemic corticosteroid therapy in Japanese patients range from 40-70%, depending on the donors. No improvement within 5 days after first-line therapy or progression within 3 days after first-line therapy could make patients eligible for second-line treatment. However, due to there being few treatment options for steroid-resistant acute GVHD, decisions to initiate second-line treatment are on occasion made 2-3 weeks after first-line therapy in Japan. Previous studies do not support the choice of any specific agent for second-line treatment of acute GVHD. Anti-thymocyte globulin and mesenchymal stem cells are covered by health insurance in Japan. Establishment of new evidence for GVHD treatment is required.

Human T-cell leukemia virus type 1 (HTLV-1) spreads through cell-to-cell transmission in vivo. HTLV-1 mainly infects CD4+ T cells in vivo. Viral genes enable infected cells to proliferate and escape detection by the host immune system. HTLV-1 infected cells tend to infiltrate tissues, and enter breast milk and semen, thereby infecting a new host. HTLV-1 bZIP factor (HBZ) causes overproduction of interferon gamma, which is associated with inflammation and lymphomagenesis. Thus, the strategies by which HTLV-1 proliferates and survives in infected cells are promoted, which is thought to induce ATL and inflammatory diseases in infected individuals.

Long survival is obtained in 30-40% of adult T-cell leukemia-lymphoma (ATL) patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT) using HLA-matched related or unrelated donors. Myeloablative conditioning is generally used for patients 55 years of age and older, while reduced intensity conditioning is given to those between 50-70 years of age. Overall survival periods do not differ significantly between these two conditioning methods. Survival rates with cord blood transplantation are not inferior to those obtained with bone marrow transplantation or peripheral blood stem cell transplantation. Prognostic factors such as age, gender, performance status, disease status at transplantation and serum soluble interleukin-2 receptor are known to have an impact in ATL patients receiving allo-HSCT. Mild acute graft-versus host disease is associated with good overall survival. Cessation of immunosuppressants or donor lymphocyte infusion often induces another remission in relapsed ATL patients after allo-HSCT. This phenomenon is regarded as a graft-versus-ATL effect mediated by activated cytotoxic T-cells. Donor cell derived-ATL has, on rare occasion, been reported in patients receiving allo-HSCT from HTLV-1 carrier donors. Special attention should be paid to the use of mogamulizumab before allo-HSCT, since this agent kills normal regulatory T-cells as well as ATL cells.

Allogeneic hematopoietic stem cell transplantation (HSCT) has been applied for the treatment of inherited bone marrow failure syndromes, inherited metabolic diseases, and primary immunodeficiencies. HSCT indications for some inherited disorders are still controversial because the effects on neurocognitive function have been found to be variable, according to pre-transplant conditions including the patient's age, disease severity, disease status, and donor availability. Moreover, utmost attention must be paid to determining the preparative regimen for preventing regimen-related toxicity because the genetic effect was found to be expressed not only in the hematopoietic stem cells themselves but also in systemic tissues. Herein, recent progress and advances in the fields of HSCT for inherited diseases are reviewed.

Invasive fungal infections (IFIs) are one of the most serious complications developing after allogeneic hematopoietic stem cell transplantation (allo-HSCT). They are difficult to treat once present and usually have a fatal course in profoundly immunosuppressed patients. Upfront prevention therefore plays an important role in overcoming this threat. The combination of a protected environment and antifungal prophylaxis against Candida spp. is conventionally applied to prevent IFIs during the neutropenic period after HSCT, whereas mold-active agents are recommended for prophylaxis against Aspergillus spp. in the later period when high-dose steroids are frequently used for the treatment of graft-versus-host disease (GVHD). However, advances in transplantation technology have made the risk of IFIs more diverse and complex. Preventive strategies should be planned using the patient's background and surrounding environment as a guide for accurate evaluation of individual risks, and should also be revised to fit time-dependent changes in the patient's immune status and condition after HSCT. Sufficient knowledge of the properties of antifungal agents is also essential for maintaining the balance between the efficacy and the toxicity of the prophylaxis over time.

The treatment strategies for acute leukemia are undergoing very rapid change. Particularly for last 10 years, due to the rapid development of molecular targeted therapy and cell/gene therapies, the role of HSCT in the treatment scheme of acute leukemia has been changing. In the author's view, these recent changes should secure the role of HSCT in the comprehensive treatment scheme of acute leukemia. By appropriately combining the new agents with HSCT, therapy for acute leukemia is anticipated to become more effective. HSCT will provide the centerpiece for the treatment scheme, by setting up the “platform” for further interventions. Keeping these changes in mind, transplant physicians should now be exploring new areas of research such as interactions between these new agents and GVHD/GVL.

Immune checkpoint inhibitors, especially anti-programmed cell death-1 (PD-1) antibodies, have revolutionized cancer therapy. A PD-1 antibody, nivolumab, was the first of these agents to be approved by the Pharmaceuticals and Medical Devices Agency (PMDA) of Japan, as a new cancer drug for melanoma, in July 2014. While PD-1 mAb therapy has so far been approved only for untreated malignant melanomas and non-small cell lung cancer, many clinical studies on various types of cancer have been conducted worldwide. Immune checkpoint inhibitors target lymphocytes rather than cancer cells, and evoke an anti-tumor immune reaction. Since the activated lymphocytes recognize various tumor-associated antigens including a mutated antigen, immune checkpoint inhibitors exhibit continuous long-term effectiveness, despite the generation of genetic mutations in cancer cells. As compared with previous cancer treatments, immune checkpoint inhibitors show superior efficacy against tumors with fewer side effects. Therefore, these novel immune checkpoint inhibitor agents are anticipated to become a 4^th cancer treatment option following surgery, chemotherapy, and radiation therapy. Herein, we review the main clinical results of PD-1 mAb cancer immunotherapy obtained to date and discuss issues relevant to administering this form of treatment.

The safety and stability of the supply of blood products must be ensured for appropriate blood transfusion therapy. Various security measures need to be taken and a balanced blood donation system should be maintained by the Japanese Red Cross Society. Based on such a system, each institute needs to establish a proper management protocol and to assure adequate use of blood products, as well as creating measures to deal with adverse events associated with blood transfusion. The system for preventing transfusion errors is particularly essential. For appropriate use of blood products, the “Guideline for the Use of Blood Products” should be followed, and unnecessary use should be avoided. These are prerequisites for error-free treatment of patients. In this educational lecture, major points in performing blood transfusion in clinical practice, such as proper indications for the use of blood products associated with patient conditions or trigger levels, and important points as well as contraindications when using blood products, such as the speed of administration, will be discussed.

Adoptive immunotherapy using genetically modified T-cells is an emerging and promising treatment modality for various malignant diseases. The technology involves engineering of T-cells armed with well-characterized receptors such as T-cell receptors or chimeric antigen receptors. The latter is comprised of antibody/ligand and intracellular signaling domains. These molecules can be further modified to enhance their affinity, specificity, and several other functions. The success of adoptive immunotherapy is rooted in the application of extensive insights derived from allogeneic hematopoietic stem cell transplantations (HSCT). Herein, the historical perspectives of gene-modified T-cell therapy are discussed by comparison with the evolution of allogeneic HSCT. Furthermore, the prospects for the development and improvement of these powerful therapeutic methods are also highlighted.