Shigetaka Asano

PBSC collection from family donors in Japan: a prospective survey

Severe adverse events (SAE) and late hematological malignancies have been reported after PBSC donation. No prospective data on incidence and risk factors have been available for family donors so far. The Japan Society for Hematopoietic Cell Transplantation (JSHCT) introduced therefore in 2000 a mandatory registration system. It defined standards for donor eligibility and asked harvest centers to report any SAE immediately. All donors were examined at day 30 and were to be contacted once each year for a period of 5 years. Acute SAEs within day 30 were reported from 47/3264 donations (1.44%) with 14 events considered as unexpected and severe (0.58%). No donor died within 30 days. Late SAEs were reported from 39/1708 donors (2.3%). The incidence of acute SAEs was significantly higher among donors not matching the JSHCT standards (P=0.0023). Late hematological malignancies in PBSC donors were not different compared with a retrospective cohort of BM donors (N:1/1708 vs N:2/5921; P=0.53). In conclusion, acute and late SAEs do occur in PBSC donors at relatively low frequency but risk factors can be defined.

Current status of hematopoietic cell transplantation for adult patients with hematologic diseases and solid tumors in Japan.

A nationwide survey of hematopoietic cell transplantation (HCT) was started in Japan in 1991, and the analyzed survey data have been presented as the annual report of the Japan Society for Hematopoietic Cell Transplantation.The 10-year overall survival (OS) rates after HCT for each disease are as follows: acute myelogenous leukemia, 44.2%; acute lymphocytic leukemia, 33.7%; adult T-cell leukemia, 24.6%; chronic myelogenous leukemia, 53.3%; myelodysplastic syndrome, 37.3%; non-Hodgkin’s lymphoma, 41.5%; Hodgkin’s lymphoma, 50.8%; aplastic anemia, 72.5%; breast cancer, 37.1%; germ cell tumor, 52.6%; and ovarian cancer, 44.2%.The 5-year OS rates for multiple myeloma and lung cancer were 40.6% and 23.6%, respectively. Except in cord blood transplantation, engraftment was accomplished in more than 90% of patients.The respective frequencies of acute graft-versus-host disease (GVHD) and chronic GVHD were 41.1% and 34.9% for related bone marrow transplantation (BMT), 66.8% and 34.5% for unrelated BMT, 52.9% and 36.0% for allogeneic peripheral blood stem cell transplantation, and 53.3% and 32.1% for allogeneic cord blood transplantation. OS for each disease was analyzed by patient age, stem cell source, donor type, disease status, and disease type.These data provide objective and valuable information for hematologists as well as for patients who need HCT.

Four cases of donor cell-derived AML following unrelated cord blood transplantation for adult patients: experiences of the Tokyo Cord Blood Bank

Donor cell leukemia (DCL) is considered a rare complication following allogeneic BMT, but the actual frequency of DCL has not been specified. Cord blood (CB) is now recognized as an alternative source for stem cell transplantation (SCT), with more than 6000 CBT performed world-wide, and a few cases of DCL following CBT have been reported [13]. We report four cases of DCL that developed after unrelated CBT using clinical reports of 478 units available from 596 units shipped by the Tokyo Cord Blood Bank (Tokyo CBB). Two cases out of the four have been already reported elsewhere [2,3]. Tokyo CBB was informed of the development of DCL by the attending physicians of the recipients in CBT centers soon after a definite diagnosis was made. The feedback from CBT centers regarding the four DCL cases is summarized in Table 1. All the donors were well at a follow-up questionnaire of 612 months after birth, but further information of their health has not yet been obtained. Notification of DLC to the donors’ parents has not yet been done because DLC in the recipient does not always mean occult leukemia in the donor and we do not want to create unnecessary anxiety for the parents. The etiology of DCL is unclear and a common mechanism is unlikely according to the reported literature [46]. Several possibilities exist, including occult leukemia or a pre-leukemic state in the donor, a defect in immune surveillance, therapy-related stromal abnormalities, excess cytokine stimulation and DNA replication and/or repair errors associated with post-transplant expansion of stem/ progenitor cells. In this regard, it should be noted that these four cases developed AML, which is relatively rare in childhood acute leukemia [7], suggesting the extrinsic influences include excessive cytokine release, infectious agents and defect immunosurveillance on leukemogenesis in the CBT setting. Nevertheless, the possibility of occult leukemia in the donor raises serious problems regarding the ethical responsibilities of the CBB to the donor. Ethical, but with a scientific background, discussion should be continued regarding the cause of DCL.

Association analysis of the NOD2 gene with susceptibility to graft-versus-host disease in a Japanese population

Members of the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family participate in the innate immune system, exerting widespread effects on cytokine secretion, autophagy, and apoptosis. Recent studies in Caucasians revealed the association between mutants of NOD2, a member of the NLR family, and severity of acute graft-versus-host disease (GVHD). NOD2 polymorphism screening has been recommended for donor selection and risk assessment at bone marrow transplantation. To investigate whether NOD2 plays a role in the pathogenesis of GVHD in a Japanese population, we examined DNA from 142 bone marrow transplant patient/donor pairs to detect genetic variation in the NOD2 gene. No genetic variants of NOD2 were associated with the severity of acute GVHD in our patients. However, a weak association between a single nucleotide polymorphism in the NOD2 gene (R471C) and acute myeloid leukemia in the bone marrow patients (p = 0.029, odds ratio 4.08, 95% CI 1.22–13.67) was detected. This polymorphism was not prevalent in 479 Crohn’s disease (CD) patients in Japan. These results suggest that, in the Japanese population, unlike the Caucasian, NOD2 is not a major contributor to susceptibility to severe acute GVHD.

Single-Unit Cord Blood Transplantation after Granulocyte Colony-Stimulating Factor–Combined Myeloablative Conditioning for Myeloid Malignancies Not in Remission

High disease burden in myeloablative allogeneic hematopoietic stem cell transplantation is associated with adverse outcomes in patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). Quiescent leukemia stem cells could be induced to enter cell cycle by granulocyte colony-stimulating factor (G-CSF) administration and become more susceptible to chemotherapy. We report on the outcome of unrelated cord blood transplantation (CBT) using a conditioning regimen of 12 Gy total body irradiation, G-CSF-combined high-dose cytarabine, and cyclophosphamide in 61 adult patients with AML or advanced MDS not in remission. With a median follow-up of 97 months, the probability of overall survival and cumulative incidence of relapse at 7 years were 61.4% and 30.5%, respectively. In multivariate analysis, poor-risk cytogenetics and high lactate dehydrogenase values at CBT were independently associated with inferior survival. These data demonstrate that CBT after G-CSF-combined myeloablative conditioning is a promising curative option for patients with myeloid malignancies not in remission.

Current status of hematopoietic stem cell transplantation for acute radiation syndromes

Many people believe that hematopoietic stem cell transplantation (HSCT) together with various hematopoietic factors may aid or rescue victims of acute radiation exposure. However, nearly all patients who have received current HSCT for severe bone marrow damage in the past died relatively shortly after transplantation, even when engraftment followed by autologous blood cell recovery was observed. The causes of death in such cases involved rapidly progressing insults to many non-hematopoietic tissues, such as lung and gut, potentially exacerbated by the conditioning regimen and immune dysfunction. We should recognize that at present avoiding high-dose radiation exposure is the only safe option.

An evidence for adhesion-mediated acquisition of acute myeloid leukemic stem cell-like immaturities

For long-term survival in vitro and in vivo of acute myeloid leukemia cells, their adhesion to bone marrow stromal cells is indispensable. However, it is still unknown if these events are uniquely induced by the leukemic stem cells. Here we show that TF-1 human leukemia cells, once they have formed a cobblestone area by adhering to mouse bone marrow-derived MS-5 cells, can acquire some leukemic stem cell like properties in association with a change in the CD44 isoform-expression pattern and with an increase in a set of related microRNAs. These findings strongly suggest that at least some leukemia cells can acquire leukemic stem cell like properties in an adhesion-mediated stochastic fashion.

A versatile drug delivery system using streptavidin-tagged pegylated liposomes and biotinylated biomaterials.

Here we have developed a versatile liposome-mediated drug delivery system (DDS) allowing a strong bridge between the streptavidin-tagged liposome (SAL) and biotin (Bi)-tagged biomaterials which has strong affinity to surface proteins expressed in restricted cell lineages. This DDS was effective and specific for many leukemia cells in vitro and in vivo. When examining 6 human leukemia cell lines using calcein-encapsulated SALs in combination with Bi-granulocyte colony-stimulating factor (G-CSF), Bi-anti-CD33 monoclonal antibody (MAb) or Bi-anti-CD7 MAb, the fluorescent positive rate of each cell line was in almost proportion to degree of G-CSF receptor, CD33 or CD7 expression, respectively. More importantly, the binding ability was shown to be well maintained in a mouse xenograft model. Furthermore the cytosine arabinoside (AraC)-encapsulated SALs could kill the corresponding cells much more effectively in combination with Bi-biomaterials than free AraC, as expected. These findings strongly indicate that our SAL/Bi-biomaterial system could allow various types of medical agents to be delivered reliably and stably to the cells targeted.

FGF7 supports hematopoietic stem and progenitor cells and niche-dependent myeloblastoma cells via autocrine action on bone marrow stromal cells in vitro.

FGF1 and FGF2 support hematopoietic stem and progenitor cells (HSPCs) under stress conditions. In this study, we show that fibroblast growth factor (FGF7) may be a novel niche factor for HSPC support and leukemic growth. FGF7 expression was attenuated in mouse embryonic fibroblasts (MEFs) deficient for the MED1 subunit of the Mediator transcriptional coregulator complex. When normal mouse bone marrow (BM) cells were cocultured with Med1(+/+) MEFs or BM stromal cells in the presence of anti-FGF7 antibody, the growth of BM cells and the number of long-time culture-initiating cells (LTC-ICs) decreased significantly. Anti-FGF7 antibody also attenuated the proliferation and cobblestone formation of MB1 stromal cell-dependent myeloblastoma cells. The addition of recombinant FGF7 to the coculture of BM cells and Med1(-/-) MEFs increased BM cells and LTC-ICs. FGF7 and its cognate receptor, FGFR2IIIb, were undetectable in BM cells, but MEFs and BM stromal cells expressed both. FGF7 activated downstream targets of FGFR2IIIb in Med1(+/+) and Med1(-/-) MEFs and BM stromal cells. Taken together, we propose that FGF7 supports HSPCs and leukemia-initiating cells indirectly via FGFR2IIIb expressed on stromal cells.

Granulocyte colony-stimulating factor combined regimen in cord blood transplantation for acute myeloid leukemia: a nationwide retrospective analysis in Japan

Cord blood transplantation (CBT) from an unrelated donor has been increasingly used as an alternative transplant method for adult patients without human leukocyte antigen (HLA)-compatible related or unrelated donors.[1][1]–[4][2] However, the main disadvantage of CBT is still the limited cell dose