There was no significant improvement in the treatment of adult acute lymphoblastic leukemia (ALL) in the 1ast two decades of the 20th century. However, remarkable improvements in survival have been achieved since the beginning of the 21st century, employing new treatments such as those for AYA ALL based on pediatric protocols and Ph+ ALL chemotherapies combining imatinib with other treatments. This review introduces the frontline therapies for adult ALL and discusses the current perspectives on the treatment of this malignancy.

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Currently, several novel drugs are available for chronic lymphocytic leukemia (CLL) in Western countries. Of these drugs, those that inhibit the B-cell receptor (BCR) signaling pathway are the most promising. Ibrutinib inhibits BTK in the BCR pathway and can be administered orally. The results of several clinical trials suggest that ibrutinib is highly effective against relapsed/resistant (RR) and treatment-naïve CLL. Furthermore, ibrutinib shows equivalent efficacy on CLL with the 17p deletion. Idelalisib, which also blocks the BCR pathway, inhibits PIK3delta and induces CLL cell death. Clinical trials have shown outstanding efficacy of idelalisib against RR-CLL, especially when administered with antiCD20 antibodies. This drug is also effective against CLL with the 17p deletion. ABT-199 is another novel drug; it inhibits BCL2 signaling, not the BCR pathway, and can be administered orally. The efficacy of ABT-199 against RR-CLL has been demonstrated in a number of clinical trials. These drugs have only mild toxicity and can be used for patients in poor general condition. Unfortunately, none of these drugs have yet been approved in Japan. Rapid resolution of the ‘drug lag’ problem is necessary.

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Malignant lymphomas encompass various types of lymphoid neoplasms, possibly originating from cells in various stages of differentiation. The development of high throughput technologies based on knowledge of the human genome identifies novel mutations, epigenetic alterations, and signaling pathways characteristics of each of the lymphoma subtypes. The mutational landscape of tumors may have a clinical impact in terms of identifying rational approaches for molecular target therapy and predictive biomarkers for new therapies. This review will focus on our current understanding of underlying molecular mechanisms, new molecular target drugs, and their activity in lymphomas.

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Owing to the positive clinical benefits obtained with new agents, complete remission (CR) can be used as a surrogate for overall survival, and should be achieved. Although multiple myeloma is a heterogeneous disease in terms of myeloma cell- and patient-related risk factors, patients should receive the most effective combination therapy based on proteasome inhibitors and/or immunomodulatory drugs (IMiDs) as backbone medication irrespective of the risks encountered in the setting of induction therapy (“one-size-fits-all” therapy), followed by consolidation/maintenance therapy to achieve CR with the ultimate goal of extended survival. Myeloma-defining biomarkers have been established to identify high-risk smoldering myeloma requiring treatment. The development of salvage treatments yielding better outcomes for relapsed/refractory myeloma is urgently needed. Upcoming novel molecular targeting agents with different modes of action and immunotherapeutic agents will be integrated into myeloma treatment regimens with a great therapeutic impact, and further evolution of the treatment paradigm for multiple myeloma is eagerly anticipated.

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Marrow donor registration and cord blood banking are essential components of the infrastructure required for unrelated haemopoietic stem cell transplantations. We now have a new law to support and regulate the Marrow Donor Coordination Agency, Cord Blood Banks and the Haematopoietic Stem Cell Provision Support Organization. We also need to have a specific goal for bone marrow and peripheral blood stem cell donor registration, a minimum cord blood bank size, and the demographic data to back the medical needs for unrelated haemopoietic stem cell transplantations. To improve bone marrow and peripheral blood stem cell transplantations, we need to recruit younger adults for marrow registration and make greater efforts to shorten the coordinating period. For cord blood transplantations, uniting and empowering the cord blood collection sites is needed, to encourage and motivate obstetricians and other staff, as the quality of cord blood units is primarily determined during collection. Also, the cord blood banks must work cooperatively to provide cord blood internationally, which includes coordinating with international agencies and their regulations.

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Cord blood (CB) has been an alternative stem cell source for patients with a wide variety of hematological diseases. When compared with unrelated bone marrow transplantation (u-BMT), obvious advantages of CB are the rapid availability and tolerance of 2 HLA antigen mismatch, which have increased the chances of transplantation for patients who lack a suitable donor or need urgent transplantation. Although higher rates of engraftment failure as compared to other stem cell sources after cord blood transplantation (CBT) have been a serious concern, the mechanisms underlying these failures have gradually been clarified by analyzing accumulated clinical data, thereby contributing to improvement of engraftment. Recent large-scale retrospective comparisons of clinical outcomes between CBT and u-BMT from HLA-matched donors have obtained comparable results, and moreover, results of CBT have been promising even in elderly patients and those in non-remission status. This review describes the current status of CBT and problems to be solved, along with discussion of developing strategies aimed at improving patient outcomes.

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HLA-haploidentical hematopoietic stem cell transplantation from related donors has gained attention as an alternative treatment for patients who do not have HLA-identical siblings and lack the time to search for HLA-matched unrelated donors due to availability for nearly all individuals. As a key factor in the success of this approach is depletion of donor T cells, HLA-haploidentical transplantation has rapidly gained acceptance worldwide with the development of three platforms: 1) CD34-positive cell selection using CliniMACS^®; 2) the conditioning regimen with anti-thymocyte globulin; and 3) a recently-developed, post-transplant cyclophosphamide regimen. Since the high efficacy of T-cell-depletion provides both sufficient suppression of GVHD and a high risk of opportunistic infection, there is an urgent need to strengthen the prevention of viral infections. On the other hand, conditioning with ATG and the post-transplant cyclophosphamide regimen are becoming the strategies mainly used in haploidentical transplantation because of high practicability and low risk of infection, though these platforms necessitate other drugs for GVHD prophylaxis due to the low efficacy of T cell depletion. Together with progress in these platforms, outcomes of haploidentical transplantation are comparable to outcomes of HLA-matched transplants. Currently, HLA-haploidentical transplantation is increasingly being recognized as a novel breakthrough in hematopoietic stem cell transplantation.

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Human herpesvirus (HHV)-6 belongs to the Betaherpesvirinae subfamily of human herpesviruses. Primary HHV-6 infection commonly causes exanthem subitum. Like other herpesviruses, HHV-6 is capable of persisting in the host after the primary infection. Under conditions of immunosuppression, latent HHV-6 can be reactivated. Between 30% and 70% of patients who undergo allogeneic hematopoietic cell transplantation (allo-HCT) experience HHV-6 reactivation at 2-4 weeks after transplantation. Accumulating evidence indicates that HHV-6 is an actual cause of encephalitis after allo-HCT. Risk factors for HHV-6 encephalitis include cord blood transplantation and an inflammatory milieu, which occurs in the early period after allo-HCT. Although HHV-6 encephalitis is associated with a poor prognosis, no validated treatments or preventative measures have as yet been established. HHV-6 reactivation may also cause myelitis, bone marrow suppression, lung disease, hepatitis, delirium, and graft-versus-host disease. However, such associations have not been consistently demonstrated and causality remains uncertain. This review updates the latest information regarding the clinical syndrome accompanying HHV-6 reactivation, with a particular focus on HHV-6 encephalitis, in the form of a series of questions and answers.

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Platelet transfusion is indispensable for current medical treatments of hematological disorders. However, alternative platelet sources are urgently needed due to the inadequate donor blood supply, particularly of HLA/HPA-matched platelets. The advent of ‘iPS cell (iPSC) technology’ was considered in light of this problem, which yielded the idea of iPSC-derived platelet production. The safety of iPSC-derived cell therapy is critical, but platelets can be gamma-irradiated prior to their use. Thus, there is an advantage in terms of clinical application. The remaining developmental aim of the in vitro iPSC-derived platelet generation process is to further scale up industrialized culture and production for the packaging of washed-type platelet concentrates, and a laboratory scale production system has already been optimized in preparation for meeting this goal.

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Congenital thrombophilia is a thrombotic diathesis caused by a variety of genetic abnormalities in blood coagulation factors or their inhibitory factors associated with physiological thrombus formation. Patients with congenital thrombophilia often present with unusual clinical episodes of venous thrombosis (occasionally combined with pulmonary embolism, known as venous thromboembolism) at a young age and recurrence in atypical vessels, such as the mesenteric vein and superior sagittal sinus, often with a family history of this condition. Studies in Japan as well as in western countries have shown congenital thrombophilia to be caused by a wide variety of genetic abnormalities in natural anticoagulant proteins, such as antithrombin, protein C, and protein S. However, there may still be many unknown causes of hereditary thrombosis. We recently reported a case of hereditary thrombosis induced by a novel mechanism of antithrombin resistance, that is, congenital thrombophilia caused by a gain-of-function mutation in the gene encoding the coagulation factor prothrombin.

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Heparin-induced thrombocytopenia (HIT) is a prothrombotic side effect of heparin therapy caused by HIT antibodies, i.e., anti-platelet factor 4 (PF4)/heparin IgG with platelet-activating properties. For serological diagnosis, antigen immunoassays are commonly used worldwide. However, such assays do not indicate their platelet-activating properties, leading to low specificity for the HIT diagnosis. Therefore, over-diagnosis is currently the most serious problem associated with HIT. The detection of platelet-activating antibodies using a washed platelet activation assay is crucial for appropriate HIT diagnosis. Recent advances in our understanding of the pathogenesis of HIT include it having several 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 on heparin re-exposure is lacking. In addition, HIT antibodies are relatively short-lived, unlike those in a secondary immune response. These lines of evidence suggest that the mechanisms underlying HIT antibody formation may be compatible with a non-T cell-dependent immune reaction. These atypical clinical and serological features should be carefully considered while endeavoring to accurately diagnose HIT, which leads to appropriate therapies such as immediate administration of an alternative anticoagulant to prevent thromboembolic events and re-administration of heparin during surgery involving cardiopulmonary bypass when HIT antibodies are no longer detectable.

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Employing newly developed imaging techniques, the spatio-temporal regulatory mechanism of fibrinolysis by platelets and vascular endothelial cells has been clarified. Upon activation, platelets release polyphosphate and inhibitors of fibrinolysis, and modify fibrin fibers which are relatively resistant to fibrinolysis. Platelets, in turn, initiate fibrinolysis. The details of the mechanism by which vascular endothelial cells (VECs) maintain high fibrinolytic potential, as well as how VECs develop anti-fibrinolytic activity, have also been clarified. These mechanisms as well as their modifications in response to inflammation are discussed herein. Newly developed drugs targeting fibrinolytic components are also introduced.

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Since the long-term safety profile of tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia (CML) therapy has not been well characterized, we investigated renal impairment in 50 CML patients treated with TKI in our institute. During the median follow up period of 63 months, 29% of patients developed chronic kidney disease (CKD). Although the glomerular filtration rate (GFR) gradually declined, it dropped most markedly in the first 2 years after starting TKI. The CKD incidence was higher in patients older than 40 years or with decreased GFR, hypertension, or dyslipidemia at baseline. These findings highlight the necessity of careful monitoring of renal function in TKI-treated CML patients with these risk factors.

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Background: LMB chemotherapy based on the FAB LMB96 study is internationally accepted as one of the standard treatments for pediatric B-cell non-Hodgkin lymphoma (B-NHL), though experience with this regimen in Japan is very limited. Since 2009, we have administered LMB chemotherapy to children with B-NHL at the National Center for Child Health and Development. Thus, we herein report the clinical characteristics and outcomes of 13 children with B-NHL given LMB chemotherapy. Results: Median age was 7.5 years. Five patients were girls and 8 were boys. Nine were subclassified as having Burkitt lymphoma and 4 as having diffuse large B-cell lymphoma. According to the St. Jude staging system, 3, 4, 2, 1, and 3 patients had stages 1, 2, 3, 4, and B-ALL disease, respectively. According to the LMB group classification system, nine patients were classified into Group B and four into Group C. At a median follow-up of 2.3 years, all patients are alive without lymphoma relapse. In Group C, myelosuppression and severe mucositis were the main adverse events especially during induction therapy. High-dose methotrexate at a dose of 8 g/m² was manageable using standard supportive therapy even with 24-hour infusion. Conclusion: Our experience indicates the feasibility of LMB chemotherapy for Japanese children with B-NHL.

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Primary gastrointestinal follicular lymphoma (FL) has an indolent clinical presentation and many of cases are diagnosed incidentally during routine endoscopic examinations. Herein, we present 3 cases with FL of the small intestine developed massive intestinal hemorrhage that necessitated blood transfusion. In all three patients, upper and lower endoscopic examinations failed to detect the bleeding sites. Eventually, video capsule endoscopies identified ulcerative lesions in the jejunum and biopsies using single- or double-balloon endoscopy confirmed the FL diagnosis in our three cases. The respective clinical stages according to the Lugano system were I, II-1 and II-1. PET-CT did not play a significant role in identifying the gastrointestinal lesions. Two patients received rituximab monotherapy and achieved a complete response. The other remains under observation after termination of antiplatelet drug therapy. Generally, the macroscopic appearance of multiple whitish nodules and the absence of symptoms represent the typical clinical picture of gastrointestinal FL. However, this study demonstrates that patients with ulcerative lesions may be at risk for massive bleeding. Further discussion is required to determine the optimal indications for total endoscopic examination of the small intestine.

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A medical check-up revealed severe anemia in an 85-year-old man who had been diagnosed with Waldenström macroglobulinemia 11 years previously. On the other hand, prolonged PT and aPTT were demonstrated on admission, and were attributed to a significant decrease in factor X activity. These abnormalities were all considered to be have been caused by an exacerbation of the underlying disease and, thus, chemotherapy with the RCD regimen (rituximab, cyclophosphamide, dexamethasone) was started. No significant improvement was obtained and the patient died suddenly on day 154. AL amyloidosis was diagnosed by histopathological examinations and also confirmed by a sequence analysis of amyloid protein. This case with Waldenström macroglobulinemia complicated by AL amyloidosis and recurrent factor X deficiency is quite rare.

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Acquired thrombotic thrombocytopenic purpura (TTP) is caused by autoantibodies against ADAMTS13. TTP patients run a rapidly fatal course unless immediate plasma exchange (PEX) is initiated upon diagnosis. Herein, we report a 72-year-old man with TTP, which developed after he underwent artificial blood vessel replacement surgery for an abdominal aneurysm with impending rupture. In the perioperative period, the patient received several platelet transfusions for severe thrombocytopenia (minimum platelet count: 0.6×10⁴/μl). Thereafter, he was admitted to our department for rapidly progressing coma with multiple cerebral infarctions, and was transferred to the ICU. Based on the tentative diagnosis of TTP, we immediately began PEX and steroid pulse therapy. The diagnosis was confirmed thereafter by markedly reduced ADAMTS13 activity (<0.5%) and his being positive for the ADAMTS13 inhibitor. We performed PEX for five consecutive days and administered high-dose prednisolone (PSL). On the second hospital day (HD), his platelet count rose along with improvement of his consciousness level. The ADAMTS13 inhibitor was not detected on the 10th HD. TTP did not relapse and his general condition improved despite tapering of PSL. In this case, by closely monitoring ADAMTS13-related parameters and minimizing the number of plasma exchanges, the patient was able to achieve a remission without the use of boosting inhibitors.

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