Generation of rat pancreas in mouse by interspecific blastocyst injection of pluripotent stem cells.

The complexity of organogenesis hinders in vitro generation of organs derived from a patient's pluripotent stem cells (PSCs), an ultimate goal of regenerative medicine. Mouse wild-type PSCs injected into Pdx1(-/-) (pancreatogenesis-disabled) mouse blastocysts developmentally compensated vacancy of the pancreatic "developmental niche," generating almost entirely PSC-derived pancreas. To examine the potential for xenogenic approaches in blastocyst complementation, we injected mouse or rat PSCs into rat or mouse blastocysts, respectively, generating interspecific chimeras and thus confirming that PSCs can contribute to xenogenic development between mouse and rat. The development of these mouse/rat chimeras was primarily influenced by host blastocyst and/or foster mother, evident by body size and species-specific organogenesis. We further injected rat wild-type PSCs into Pdx1(-/-) mouse blastocysts, generating normally functioning rat pancreas in Pdx1(-/-) mice. These data constitute proof of principle for interspecific blastocyst complementation and for generation in vivo of organs derived from donor PSCs using a xenogenic environment.

Prolonged shedding of viable SARS-CoV-2 in immunocompromised patients with haematological malignancies: A prospective study.

Prolonged SARS-CoV-2 infection in immunocompromised individuals has been scattered, but the details remain unclear. We conducted a prospective study with 26 COVID-19 patients with haematological malignancies to determine viral shedding kinetics and characteristics. We obtained nasopharyngeal swabs from the patients 21-28 days post-onset for a PCR test and performed virus isolation from the PCR-positive samples. A viable virus was detected in five patients (19.2%), all of whom had malignant lymphoma. Those patients had significantly lower CD4+ T-cell counts than the PCR-negative patients. A comparison of previous chemotherapy showed that anti-CD20 antibodies and bendamustine may be risk factors for prolonged viral shedding.

Subclinical minute FLT3-ITD clone can be detected in clinically FLT3-ITD-negative acute myeloid leukaemia at diagnosis.

Recent advances in next-generation sequencing (NGS) have enabled the detection of subclinical minute FLT3-ITD. We selected 74 newly diagnosed, cytogenetically normal acute myeloid leukaemia (AML) samples in which FLT3-ITD was not detected by gel electrophoresis. We sequenced them using NGS and found minute FLT3-ITDs in 19 cases. We compared cases with clinically relevant FLT3-ITD (n = 37), cases with minute FLT3-ITD (n = 19) and cases without detectable FLT3-ITD (n = 55). Molecular characteristics (location and length) of minute FLT3-ITD were similar to those of clinically relevant FLT3-ITD. Survival of cases with minute FLT3-ITD was similar to that of cases without detectable FLT3-ITD, whereas the relapse rate within 1 year after onset was significantly higher in cases with minute FLT3-ITD. We followed 18 relapsed samples of cases with clinically FLT3-ITD-negative at diagnosis. Two of 3 cases with minute FLT3-ITD relapsed with progression to clinically relevant FLT3-ITD. Two of 15 cases in which FLT3-ITD was not detected by NGS relapsed with the emergence of minute FLT3-ITD, and one of them showed progression to clinically relevant FLT3-ITD at the second relapse. We revealed the clonal dynamics of subclinical minute FLT3-ITD in clinically FLT3-ITD-negative AML. Minute FLT3-ITD at the initial AML can expand to become a dominant clone at relapse.

Dominant-negative type of IKZF1 deletion showed a favorable prognosis in adult B-cell acute lymphoblastic leukemia.

IKZF1 deletion is a recurrent genomic alteration in B-cell acute lymphoblastic leukemia (B-ALL) and is divided into dominant-negative (DN) and loss of function (LOF) deletions. The prognostic impact of each deletion has not been fully elucidated. We retrospectively analyzed 117 patients with adult B-ALL including 60 patients with BCR::ABL1-positive B-ALL and 57 patients with BCR::ABL1-negative B-ALL by the fluorescence in situ hybridization (FISH) method for IKZF1 deletion and multiplex PCR for the 4 most common IKZF1 deletions (∆4-7, ∆2-7, ∆2-8, and ∆4-8). Samples, in which IKZF1 deletion was detected by FISH but a specific type of deletion was not identified by the PCR, were categorized as "other." Patients were classified into a DN group that had at least 1 allele of ∆4-7 (n = 23), LOF and other group (n = 40), and wildtype group (n = 54). DN type IKZF1 deletions were found in 33.3% of BCR::ABL1-positive cases and 5.2% of BCR::ABL1-negative cases. LOF and other type IKZF1 deletions were found in 43.4% of BCR::ABL1-positive cases and 24.6% of BCR::ABL1-negative cases. Patients with the DN group showed significantly higher overall survival (OS) than that of the LOF and other and WT groups (P = 0.011). Multivariate analysis including age, WBC counts, complex karyotype, and DN type IKZF1 deletion showed that the DN type of IKZF1 deletion (HR = 0.22, P = 0.013) had a positive impact and age ≥ 65 (HR = 1.92, P = 0.029) had a negative impact on OS. The prognostic impact of IKZF1 deletion depends on the type of deletion and DN type of IKZF1 deletion showed better prognosis in adult B-ALL patients.Clinical trial registration This study was part of a prospective observational study (Hokkaido Leukemia Net, UMIN000048611). It was conducted in compliance with ethical principles based on the Helsinki Declaration and was approved by the institutional review board of Hokkaido University Hospital (#015-0344).

Clinical implications of NUP98::NSD1 fusion at diagnosis in adult FLT3-ITD positive AML.

OBJECTIVES: The cryptic fusion oncogene NUP98::NSD1 is known to be associated with FLT3-ITD mutation in acute myeloid leukemia (AML), and an independent poor prognostic factor in pediatric AML. However, there are little data regarding the clinical significance of NUP98::NSD1 in adult cohort. METHODS: We conducted a multicenter retrospective study to investigate the prevalence, clinical characteristics, and prognostic impact of NUP98::NSD1 in adult FLT3-ITD-positive AML patients. RESULTS: In a total of 97 FLT3-ITD-positive AML patients, six cases (6.2%) were found to harbor the NUP98::NSD1 fusion transcript. NUP98::NSD1 positive cases had significantly higher platelet counts and a higher frequency of FAB-M4 morphology than NUP98::NSD1 negative cases. NUP98::NSD1 was found to be mutually exclusive with NPM1 mutation, and was accompanied by the WT1 mutation in three of the six cases. The presence of NUP98::NSD1 fusion at the time of diagnosis predicted poor response to cytarabine-anthracycline-based intensive induction chemotherapy (induction failure rate: 83% vs. 36%, p = .038). Five of the six cases with NUP98::NSD1 underwent allogeneic hematopoietic stem cell transplantation (HSCT). Two of the five cases have successfully maintained remission, with one of them being rescued through a second HSCT. CONCLUSIONS: Detecting NUP98::NSD1 in adult FLT3-ITD-positive AML is crucial to recognizing chemotherapy-resistant group.

[Hb Hirosaki hemoglobinopathy initially suspected due to low oxygen saturation levels and abnormally low HbA1c levels].

More than 1,200 hemoglobin variants are identified worldwide, and approximately 200 variants are detected in one of 3,000 Japanese people. Most of these patients are asymptomatic; however, some patients had hemolytic anemia or cyanosis. Herein, we report a case of a 49-year-old woman with prolonged fatigability after experiencing symptoms of common cold and intermittent brown urine. Her clinical data showed mild hemolysis, a disparity between SpO2 (93%) and pO2 (85.2 mmHg), and abnormally low HbA1c levels (3.7%). These findings lead to the diagnosis of unstable hemoglobin variant, Hb Hirosaki. A simple series of tests using pulse oximetry, an arterial blood gas analysis, measurement of HbA1c levels, or identifying the HPLC chromatogram of HbA1c can be the factors associated with the diagnosis of hemoglobinopathy.

Disseminated fusariosis emerged from prolonged local genital infection after cord blood transplantation.

Disseminated fusariosis (DF) is a rare life threatening fungal infection in immunocompromised hosts. We herein report a case of a fatal DF mimicking varicella zoster virus (VZV) infection that was emerged from a localized genital infection during cord blood transplantation (CBT) in a patient with severe aplastic anemia (SAA). The patient developed an ulcer following small painful vesicles mimics herpes simplex virus infection (HSV) on the glans penis before CBT, but a Fusarium species was identified. Despite administration of voriconazole, liposomal amphotericin B and granulocyte transfusion, the lesion was extended to extensive skin looked like VZV infection and the patients died after CBT. Massive fusarium infiltration was detected in multiple organs at autopsy. A genetic analysis of the mold identified Fusarium solani after his death. It should be noted that in patients with fusarium infection, localized and disseminated lesions of fusarium infection sometimes mimic HSV and VZV infections, which hampers an early diagnosis.

Leukemogenic kinase FIP1L1-PDGFRA and a small ubiquitin-like modifier E3 ligase, PIAS1, form a positive cross-talk through their enzymatic activities.

Fusion tyrosine kinases play a crucial role in the development of hematological malignancies. FIP1L1-PDGFRA is a leukemogenic fusion kinase that causes chronic eosinophilic leukemia. As a constitutively active kinase, FIP1L1-PDGFRA stimulates downstream signaling molecules, leading to cellular proliferation and the generation of an anti-apoptotic state. Contribution of the N-terminal FIP1L1 portion is necessary for FIP1L1-PDGFRA to exert its full transforming activity, but the underlying mechanisms have not been fully characterized. We identified PIAS1 as a FIP1L1-PDGFRA association molecule by yeast two-hybrid screening. Our analyses indicate that the FIP1L1 portion of FIP1L1-PDGFRA is required for efficient association with PIAS1. As a consequence of the association, FIP1L1-PDGFRA phosphorylates PIAS1. Moreover, the kinase activity of FIP1L1-PDGFRA stabilizes PIAS1. Therefore, PIAS1 is one of the downstream targets of FIP1L1-PDGFRA. Moreover, we found that PIAS1, as a SUMO E3 ligase, sumoylates and stabilizes FIP1L1-PDGFRA. In addition, suppression of PIAS1 activity by a knockdown experiment resulted in destabilization of FIP1L1-PDGFRA. Therefore, FIP1L1-PDGFRA and PIAS1 form a positive cross-talk through their enzymatic activities. Suppression of sumoylation by ginkgolic acid, a small molecule compound inhibiting a SUMO E1-activating enzyme, also destabilizes FIP1L1-PDGFRA, and while the tyrosine kinase inhibitor imatinib suppresses FIP1L1-PDGFRA-dependent cell growth, ginkgolic acid or siRNA of PIAS1 has a synergistic effect with imatinib. In conclusion, our results suggest that sumoylation by PIAS1 is a potential target in the treatment of FIP1L1-PDGFRA-positive chronic eosinophilic leukemia.

FIP1L1 presence in FIP1L1-RARA or FIP1L1-PDGFRA differentially contributes to the pathogenesis of distinct types of leukemia.

FIP1-like 1 (FIP1L1) is associated with two leukemogenic fusion genes: FIP1L1-retinoic acid receptor alpha (RARA) and FIP1L1-platelet-derived growth factor receptor alpha (PDGFRA). Analyses of a series of deletion mutants revealed that the FIP1 motif in FIP1L1-RARA plays a pivotal role in its homodimerization and transcriptional repressor activity. However, in FIP1L1-PDGFRA, the C-terminal PDGFRA portion possesses the ability of forming a homodimer by itself, making FIP1L1 dispensable for constitutive activation of this kinase. Both the full-length and the C-terminal PDGFRA portion of FIP1L1-PDGFRA could transform the IL-3-dependent hematopoietic cell line, BAF-B03. Moreover, when either the full-length or the C-terminal PDGFRA portion of FIP1L1-PDGFRA was introduced in these cells, they grew in the absence of IL-3. The cells having the C-terminal PDGFRA portion of FIP1L1-PDGFRA, however, were partially IL-3 dependent, whereas the cells having the full-length FIP1L1-PDGFRA became completely IL-3 independent for their growth. Taken together, these results show that FIP1L1 differentially contributes to the pathogenesis of distinct types of leukemia.

Prognostic impact of FLT3-ITD, NPM1 mutation and CEBPA bZIP domain mutation in cytogenetically normal acute myeloid leukemia: a Hokkaido Leukemia Net study.

Mutation status of FLT3, NPM1, and CEBPA is used to classify the prognosis of acute myeloid leukemia, but its significance in patients with cytogenetically normal (CN) AML is unclear. We prospectively analyzed these genes in 295 patients with CN-AML and identified 76 (25.8%) FLT3-ITD, 113 (38.3%) NPM1 mutations, and 30 (10.2%) CEBPA biallelic mutations. We found that patients with FLT3-ITD had a poor prognosis at any age, while patients with CEBPA biallelic mutation were younger and had a better prognosis. FLT3-ITD and NPM1 mutations were correlated, and the favorable prognostic impact of being FLT3-ITD negative and NPM1 mutation positive was evident only in patients aged 65 years or more. For CEBPA, 86.7% of the patients with biallelic mutation and 9.1% of patients with the single allele mutation had in-frame mutations in the bZIP domain, which were strongly associated with a favorable prognosis. Multivariate analysis showed that age < 65 years, FLT3-ITD and CEBPA bZIP in-frame mutation were independent prognostic factors. The results suggest that analyzing these gene mutations at diagnosis can inform selection of the optimal intensity of therapy for patients with CN-AML.

Clinical features of complex karyotype in newly diagnosed acute myeloid leukemia.

Complex karyotype acute myeloid leukemia (CK-AML) has been classified as an adverse-risk subtype. Although a few reports have further classified CK-AML as typical (including monosomy of chromosomes 5, 7 and 17 or deletion of 5q, 7q and/or 17p) or atypical, the clinical features of these subtypes in Japanese patients remain unclear. We retrospectively analyzed a total of 115 patients with CK-AML, including 77 with typical CK-AML and 38 with atypical CK-AML. Median overall survival (OS) was significantly shorter in patients with typical CK-AML than atypical CK-AML (143 days vs. 369 days, P = 0.009). Among patients with typical CK-AML, those with monosomy 17 or deletion of 17p had significantly shorter OS than patients without such abnormalities (105 days vs. 165 days, P = 0.033). TP53 mutations were more predominant in patients with typical CK-AML than in patients with atypical CK-AML (69.7% vs. 32.4%, P < 0.001). Patients with typical CK-AML had a poor prognosis regardless of TP53 mutation status. Among patients with atypical CK-AML, however, prognosis was worse for those with the TP53 mutation than those without the mutation. In conclusion, prognosis is extremely poor for both typical CK-AML and atypical CK-AML with TP53 mutation.

A role for IL-34 in osteolytic disease of multiple myeloma.

Multiple myeloma (MM) is a hematological malignancy that grows in multiple sites of the axial skeleton and causes debilitating osteolytic disease. Interleukin-34 (IL-34) is a newly discovered cytokine that acts as a ligand of colony-stimulating factor-1 (CSF-1) receptor and can replace CSF-1 for osteoclast differentiation. In this study, we identify IL-34 as an osteoclastogenic cytokine that accelerates osteolytic disease in MM. IL-34 was found to be expressed in the murine MM cell line MOPC315.BM, and the expression of IL-34 was enhanced by stimulation with proinflammatory cytokines or by bone marrow (BM) stromal cells. MM-cell-derived IL-34 promoted osteoclast formation from mouse BM cells in vitro. Targeting Il34 by specific small interfering RNA impaired osteoclast formation in vitro and attenuated osteolytic disease in vivo. In BM aspirates from MM patients, the expression levels of IL-34 in CD138+ populations vary among patients from high to weak to absent. MM cell-derived IL-34 promoted osteoclast formation from human CD14+ monocytes, which was reduced by a neutralizing antibody against IL-34. Taken together, this study describes for the first time the expression of IL-34 in MM cells, indicating that it may enhance osteolysis and suggesting IL-34 as a potential therapeutic target to control pathological osteoclastogenesis in MM patients.

Long-term administration of a low-molecular-weight heparin contributed to successful treatment in a patient with primary mediastinal large B-cell lymphoma and venous thromboembolism.

The case of a 16-year-old girl with primary mediastinal large B-cell lymphoma who had thrombosis in the brachiocephalic, subclavian, and internal jugular veins at presentation is reported. MACOP-B chemotherapy plus radiation therapy could be the first-line strategy, but MACOP-B increases the risk of thrombosis. Although an effective method for initial treatment of venous thromboembolism (VTE) in cancer patients has not been established, recent studies revealed that the administration of a low-molecular-weight heparin (LMWH) was effective for secondary prevention of VTE. Therefore, the patient in this case was treated with MACOP-B plus rituximab followed by radiation therapy, and an LMWH was administered through the course of treatment. She achieved complete remission and never suffered from VTE. This case suggests that long-term administration of an LMWH contributes to the primary improvement and secondary prevention of VTE even in patients who are at high risk for thrombosis.

[Loss of CD20 expression following rituximab-combined chemotherapy in CD20-positive and CyclinD1-positive multiple myeloma].

Several studies have confirmed that CD20 is expressed in about 20% of multiple myeloma (MM) cases. This is closely related to a chromosomal translocation between chromosome 11 and chromosome 14, which results in the expression of CyclinD1. The use of rituximab (RIT) in the treatment of CD20-positive MM has been reported, however its effectiveness is still not well established. We encountered a case of CD20-positive/CyclinD1-positive MM; interestingly, CD20 expression could not be detected in MM cells following RIT-combined chemotherapy, while it gradually recovered when RIT therapy was discontinued. This is the first report in which the transition of CD20 expression was accurately analyzed by flow cytometry and immunohistochemical staining before, during and after RIT treatment. Consequently, this case provides insight regarding the mechanism through which CD20 expression is lost following RIT therapy for CD20-positive lymphoid neoplasm, as well as the efficacy of RIT in CD20-positive MM.

Expansion of natural killer cell receptor (CD94/NKG2A)-expressing cytolytic CD8 T cells and CD4+CD25+ regulatory T cells from the same cord blood unit.

OBJECTIVE: Cord blood contains a significant number of precursor cells that differentiate to cytotoxic effector cells and immunoregulatory cells. We tried to expand inhibitory natural killer cell receptor CD94-expressing CD8 T cells with cytolytic activity and CD4(+)CD25(+) regulatory T cells from the same cord cell unit. METHODS: Cytotoxic CD94-expressing CD8 T cells were expanded from CD4-depleted cord blood using an immobilized anti-CD3 monoclonal antibody and a cytokine and also CD4(+)CD25(+) regulatory T cells were expanded from a CD4-enriched fraction derived from the same cord blood unit using anti-CD3/CD28 monoclonal antibody-coated Dynabeads and cytokines. RESULTS: We were able to obtain a more than 1000-fold expansion of CD94-expressing CD8 T cells and a more than 50-fold expansion of CD4(+)CD25(+) cells from the same cord blood unit. These expanded CD4(+)CD25(+) cells expressed FoxP3 mRNA at a level about 100-fold higher than that in isolated CD25(-) cells and could suppress allogeneic mixed lymphocyte culture by >80% (effector cells: CD4(+)CD25(+) cells = 2:1). Cytolytic activities of purified CD94-expressing cells detected by a 4-hour (51)Cr release assay against K562 were >60%. Coculture of CD94-expressing cells with expanded CD4(+)CD25(+) cells did not have any effect on cytolytic activities of purified CD94-expressing cells against K562 cells. CONCLUSION: These expanded cytolytic CD94-expressing CD8 cells might be able to induce a graft-vs-leukemia effect without enhancing graft-vs-host disease, and CD4(+)CD25(+) cells might be able to suppress allogeneic responses, including graft-vs-host disease and graft rejection after cord blood transplantation.

Effect of macrophage migration inhibitory factor (MIF) on acute graft-versus-host disease in a murine model of allogeneic stem cell transplantation.

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). We examined whether MIF has an influence on the development of aGVHD and survival using BALB/c-based MIF knock-out (MIF KO) mice. Although MIF expression was observed in lymphocytes that had infiltrated the liver during aGVHD in both wild-type (WT) and MIF KO mice that received bone marrow cells (BM) and spleen cells (SP) from C57BL/6N mice, no significant difference was found in severity of aGVHD or survival rate between the two groups of mice. However, MIF level had decreased at 1 week after HSCT when MIF KO mice were used as the recipients. In the experiment using MIF KO mice as the donors, the recipient mice transplanted with BM and SP from MIF KO mice had significantly lower aGVHD scores on days 14, 21, and 35 than those in the recipient mice transplanted with BM and SP from WT-BALB/c mice. Histopathological findings supported these observations, showing that the bile ducts and lobules in the liver were destroyed by infiltrating MIF-expressing lymphocytes in the recipients of BM and SP from WT-BALB/c mice, while the bile ducts were not destroyed even by infiltrating MIF-deficient lymphocytes in the recipients of BM and SP from MIF KO mice. Therefore, these findings suggest that MIF has an effect on the development of aGVHD in a murine model of allogeneic stem cell transplantation.

Successful reduced-intensity stem cell transplantation (RIST) for a patient with malignant lymphoma and an ileostomy.

A 56-year-old man was admitted for treatment of non-Hodgkin's lymphoma (NHL). He had undergone a partial small bowel and colon resection and had ileostomy due to bowel perforation induced by chemotherapy. After the operation, his disease status was in partial remission (PR), and reduced-intensity allogeneic stem cell transplantation (RIST) was therefore performed for further improvement of disease status. The conditioning regimen consisted of fludarabine and busulfan. Graft-versus-host disease (GVHD) prophylaxis was performed using cyclosporin and short-term methotrexate. The occurrence of serious infection during the period of neutropenia was prevented by the administration of amphotericin B, fluconazole and acyclovir. This case report provides important information on the appropriate strategy for treating patients who have ileostomy.