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Intensity-modulated radiation therapy (IMRT) helps achieve good radiation dose conformity and precise dose evaluation. We conducted a single-centre prospective study to assess the safety and feasibility of total body irradiation with IMRT (IMRT-TBI) using helical tomotherapy in allogeneic haematopoietic stem cell transplantation (allo-HSCT).Thirty-nine adult patients with haematological malignancy (acute lymphoblastic leukaemia [The mean doses for the lungs and kidneys were 7.50 and 9.11 Gy, respectively. The mean maximum dose for the lens (right/left) was 5.75/5.87 Gy. The 2-year overall survival (OS), disease-free survival (DFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 69, 64, 18 and 18%, respectively. Thirty-six patients developed early adverse events (AEs) (including four patients with Grade 3/4 toxicities), most of which were reversible oral mucositis and may partially have been related to IMRT-TBI. However, the incidence of toxicity was comparable to conventional TBI-based conditioning transplantation. None of the patients developed primary graft failure, or Grade III-IV acute graft-versus-host disease (GVHD). In late complications, chronic kidney disease was observed in six patients, a lower incidence compared to conventional TBI-based conditioning transplantation. No radiation pneumonitis or cataracts were observed in any of the patients.IMRT-TBI is safe and feasible for haematological malignancies with acceptable clinical outcomes.KEY MESSAGESIMRT-TBI-helical tomotherapy aids in accurate dose calculation and conformity.It could be used without any considerable increase in the rate of TBI-related AEs.Allo-HSCT with IMRT-TBI may be an alternative to conventional TBI for clinical use.

Sarcopenia is a prognostic factor for cancer. Because creatinine is formed from creatine phosphate in muscle tissue, urinary creatinine excretion (UCE) serves as an index of muscle volume. However, as of yet, there are no studies assessing the clinical impact of UCE or weight- adjusted urinary creatinine excretion (WA-UCE) on allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. We analyzed the association between pre-transplant WA-UCE and transplant outcomes among 164 adult patients with acute myeloid leukemia in complete remission who underwent their first allo-HSCT at our center. The patients were classified into a high (

Fludarabine with intravenous busulfan (6.4 mg/kg; FB2) and fludarabine with intermediate-dose melphalan (140 mg/m2; FM140) are the most widely used reduced-intensity conditioning (RIC) regimens for allogeneic hematopoietic stem cell transplantation. FM140 generally has a lower relapse rate and higher non-relapse mortality (NRM), resulting in overall survival (OS) comparable to that seen with FB2. To evaluate the effect of reducing the melphalan dose, we retrospectively compared transplant outcomes in 156 patients who received FB2 (n = 103) or FM80 (n = 53) at our center (median age: 63 years; range 27–72 years). All patients received 4-Gy total body irradiation. Three-year OS, the cumulative incidence of relapse, and NRM were comparable between groups (FB2 vs. FM80, 58% vs. 47%, p = 0.24; 30% vs. 36%, p = 0.57; 17% vs. 21%, p = 0.44, respectively). There was no significant difference in the cumulative incidence of graft-versus-host disease (GVHD) at day 100, chronic GVHD at 3 years, or the 3-year GVHD-free/relapse-free survival rate. In the high-risk disease group, patients receiving FM80 tended to have lower 3-year OS (FB2 vs. FM80, 48% vs. 17%, p = 0.06). In summary, transplant outcomes following FB2 or FM80 were comparable except in patients with high-risk disease.

A 60-year-old woman with myelodysplastic syndrome/myeloproliferative neoplasm-unclassifiable underwent unrelated bone marrow transplantation from a human leukocyte antigen (HLA) 8/8 allele-matched male donor. Neutrophil engraftment was achieved on day 29. Fluorescence in situ hybridization of sex chromosomes demonstrated complete donor chimerism. The red blood cell and platelet transfusion dependence continued, and the neutrophil count decreased gradually. Despite prolonged administration of broad-spectrum antibiotics for febrile neutropenia, blood cultures on days 46 and 58 returned positive for Stenotrophomonas maltophilia (SM). Contrast-enhanced computed tomography revealed multiple nodules of septic emboli in the lungs and kidneys, suggesting a disseminated SM infection. Antibiotic therapy was conducted based on antimicrobial susceptibility testing. However, the blood cell count failed to normalize and a secondary graft failure was diagnosed. A HLA-haploidentical peripheral-blood stem-cell transplantation from the patient's son was performed on day 134 after the initial transplantation. Neutrophil engraftment was achieved on day 11. Red blood cells and platelets were also engrafted. After the resolution of the SM bacteremia, the patient was discharged on day 63. The prognosis of the SM bacteremia with neutropenia is poor. Antibiotic treatment based on antimicrobial susceptibility testing and a second transplant from an HLA-haploidentical donor likely contributed to the successful outcome in this patient.

A 22-year-old man with a history of mediastinal germ cell tumor, which was diagnosed at age 20 and remained disease-free after chemotherapy, was diagnosed with acute myeloid leukemia (AML) M2 in January 2020. Karyotype analysis of bone marrow (BM) specimen at diagnosis detected 47,XXY, inv (16) in all cells. Following induction treatment, he achieved complete remission with a remarkable decrease in the minimal residual disease marker. Although considered related to therapy, the AML had a prognostically favorable karyotype, and the initial treatment response was very good. He had no human leukocyte antigen-matched sibling donor candidate. Thus, allogeneic hematopoietic stem cell transplantation was not scheduled at the first complete remission. After three cycles of consolidation therapy, he remained disease-free for over one year. Karyotype analysis of BM during remission revealed that all analyzed cells harbored 47,XXY, and Klinefelter syndrome (KS) was diagnosed. Although the patient experienced an adjustment disorder on KS diagnosis, he had overcome the difficulty with the assistance of psycho-oncologists, clinical psychologists, and genetic counselors. Herein, we report this rare case of KS that manifested after AML diagnosis following mediastinal germ cell tumor treatment.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are at high risk of developing invasive pneumococcal disease (IPD) with substantial morbidity and mortality. Pneumococcal polysaccharide vaccine (PPSV23) and pneumococcal conjugate vaccine (PCV13) are the primary prevention strategy. The difference between the Japanese and international guidelines is limited except when to start PCV13. However, Japanese data regarding the incidence of IPD after allo-HSCT that include vaccination status are limited. Therefore, we aimed to study the clinical characteristics of patients with IPD following allo-HSCT, focusing on unvaccinated patients. We retrospectively reviewed allo-HSCT recipients between April 2005 and December 2018 at Komagome Hospital. Among 1,091 recipients, 11 (1008/100,000 recipients) developed 13 episodes of IPD. The median period from the first allo-HSCT to the first IPD episode was 686 days (10-3040 days). Ten patients developed IPD before vaccination, and seven of these unvaccinated patients with late-onset IPD were ineligible for vaccination based on domestic guidelines. Although appropriate treatments resulted in a good short-term prognosis, most episodes of IPD developed in unvaccinated allo-HSCT recipients. Our data support the promotion of better adherence to the current guidelines and the importance of pneumococcal vaccination even years after allo-HSCT to protect against late-onset IPD.

Cytomegalovirus (CMV) reactivation in cord blood transplantation (CBT) may result in the proliferation and maturation of natural killer (NK) cells. Similarly, a mismatch of the killer cell immunoglobulin-like receptor (KIR)-ligand induces NK cell activation. Therefore, if CMV reactivation occurs in the presence of KIR-ligand mismatch, it might improve CBT outcomes. We assessed the difference in the effect of CMV reactivation in the presence of KIR-ligand mismatch on disease relapse in the graft-versus-host direction. A total of 2840 patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, and chronic myeloid leukemia were analyzed. Among those with a HLA-Bw4/A3/A11 (KIR3DL-ligand) mismatch, CMV reactivation up to 100 days following CBT had a favorable impact on relapse (18.9% vs. 32.9%, P = 0.0149). However, this effect was not observed in cases without the KIR3DL-ligand mismatch or in those with or without a HLA-C1/C2 (KIR2DL-ligand) mismatch. The multivariate analysis suggested that CMV reactivation had a favorable effect on relapse only in cases with a KIR3DL-ligand mismatch (hazard ratio 0.54, P = 0.032). Moreover, the interaction effect between CMV reactivation and KIR3DL-ligand mismatch on relapse was significant (P = 0.039). Thus, our study reveals the association between KIR-ligand mismatches and CMV reactivation, which will enhance CBT outcomes.

There are few reports on allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult B-cell acute lymphoblastic leukemia (B-ALL) harboring t(1;19)(q23;p13.3). We used nationwide registry data of Japan for 2003–2016 to evaluate transplant outcomes and clarified prognostic factors among adult allo-HSCT recipients with B-ALL harboring t(1;19)(q23;p13.3) (n = 125). Compared with cytogenetically normal (CN) B-ALL patients (n = 1057), their 3-year overall survival (OS) rates were comparable (55.4% for t(1;19) and 54.4% for CN; P = 0.76). Considering only patients in first complete hematological remission (CR1), the 3-year OS rates remained comparable (70.5% for t(1;19) and 67.8% for CN; P = 0.86). For t(1;19) patients in CR1, minimal residual disease (MRD) at transplantation was associated with relatively worse outcomes. The 3-year OS rates were 43.6% for patients with MRD and 77.4% for those without it (P = 0.016). The 3-year relapse rates were 54.5% for patients with MRD and 12.8% for those without it (P

Cyclophosphamide (CY)-induced cardiotoxicity involves rare lethal complications. We previously reported the cardiac events of 811 allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients; 12 out of 811 recipients (1.5%) developed fatal heart failure. The mortality rate was also very high (91.6%, 11/12). CY dose (200 mg/kg or more) was reported as the independent risk factor. The main disease in patients treated with 200 mg/kg or more of CY was severe aplastic anemia (AA). Therefore, we reduced the dose of CY during conditioning for AA (from 200 to 100 mg/kg), and then we analyzed the clinical features of 294 patients who received a total dose of at least 100 mg/kg of CY. We also compared the clinical features between the current study and our previous study. The proportion of patients treated with at least 200 mg/kg of CY was reduced from 4.2% to 0%. However, CY-induced heart failure occurred in four of the 294 patients (1.4%), which was similar to the finding reported in our previous study (1.5%). Two of these four patients received a post-transplant CY (PTCy) regimen (CY 100 mg/kg). All four patients were treated in the cardiac intensive care unit (C-ICU), and two patients survived. In summary, even the CY dose of 120 mg/kg or less would cause cardiotoxicity. We should also carefully monitor patients treated with PTCy, considering the possibility of CY-induced cardiotoxicity. Early diagnosis and ICU management have contributed to improved outcomes.

Variants of the t (8;21) (q22;q22) involving chromosome 8, 21, and other chromosomes account for about 3% of all t (8;21) (q22;q22) in patients with acute myeloid leukemia (AML). However, the prognosis of AML with variant t (8;21) remains unknown due to the scarcity of reported cases. Herein we report a case of AML with t (6;21;8) (p23;q22;q22). Fluorescence in situ hybridization confirmed a RUNX1-RUNX1T1 fusion signal on the derivative chromosome 8. This is the first report on a variant of t (8;21) involving the breakpoint 6p23. After induction chemotherapy, our patient achieved complete remission and has been stable for four years.

Total body irradiation using intensity-modulated radiation therapy total body irradiation (IMRT-TBI) by helical tomotherapy in allogeneic hematopoietic stem cell transplantation (allo-HSCT) allows for precise evaluation and adjustment of radiation dosage. We conducted a single-center pilot study to evaluate the safety of IMRT-TBI for allo-HSCT recipients. Patients with hematological malignancies in remission who were scheduled for allo-HSCT with TBI-based myeloablative conditioning were eligible. The primary endpoint was the incidence of adverse events (AEs). Secondary endpoints were engraftment rate, overall survival, relapse rate, non-relapse mortality, and the incidence of acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively). Between July 2018 and November 2018, ten patients were recruited with a median observation duration of 571 days after allo-HSCT (range, 496–614). D80% for planning target volume (PTV) in all patients was 12.01 Gy. Average D80% values for lungs, kidneys and lenses (right/left) were 7.50, 9.03 and 4.41/4.03 Gy, respectively. Any early AEs (within 100 days of allo-HSCT) were reported in all patients. Eight patients experienced oral mucositis and gastrointestinal symptoms. One patient experienced Bearman criteria grade 3 regimen-related toxicity (kidney and liver). All cases achieved neutrophil engraftment. There was no grade III–IV aGVHD or late AE. One patient died of sinusoidal obstruction syndrome 67 days after allo-HSCT. The remaining nine patients were alive and disease-free at final follow-up. Thus, IMRT-TBI was well tolerated in terms of early AEs in adult patients who underwent allo-HSCT; this warrants further study with longer observation times to monitor late AEs and efficacy.

Key Clinical Message The de novo myeloid sarcoma (MS) type of acute promyelocytic leukemia (APL) is rare, and clinical features may differ from extramedullary diseases in advanced APL. Many cases occur as a spinal tumor, and some occur in the absence of bone‐marrow diseases or coagulation abnormalities. Fluorescence in situ hybridization analysis of MS tissue is useful for accurate diagnosis, even in preserved tissue.

Graft failure (GF) is a life-threatening complication after allogeneic stem cell transplantation. Although salvage cord blood transplantation (CBT) is a curative therapy for GF, the optimal immunosuppression after salvage CBT remains unknown. Using nationwide registration data, we compared the transplant outcomes of patients who developed GF and underwent salvage CBT using immunosuppressants, including calcineurin (CNI) alone (n = 177); CNI plus methotrexate (CNI+MTX, n = 150); and CNI plus mycophenolate mofetil (CNI+MMF, n = 161). The CNI+MMF group, in comparison with the CNI+MTX and CNI alone groups, demonstrated better neutrophil recovery at 30 days (62.7 vs. 42.7 vs. 53.1%, P

A 70-year-old man was admitted to our hospital due to fever, lymphadenopathy, and leukocytosis. White blood cell count was 22,700/µl with 92% blastoid cells. Bone marrow examination revealed abnormal lymphoid cell expansion. Abnormal cells expressed surface CD5 (dim), CD10, CD19, CD20, CD23 (dim) antigens, and kappa immunoglobulin light chains. Cytogenetic analysis of bone marrow cells at the time of diagnosis showed t (11:14) (q13;q32), t (14;18) (q32;q21), and t (8;14;18) (q24;q32;q21). Fluorescence in situ hybridization analyses of bone marrow identified translocations of IGH/MYC, IGH/BCL2, and IGH/CCND1. The patient was diagnosed with aggressive B-cell lymphoma with IGH/MYC, IGH/BCL2, and IGH/CCND1 translocation and was treated with various chemotherapies including R-CHOP, R-ESHAP, DA-EPOCH-R, R-hyper-CVAD, and radiotherapy. However, the lymphoma recurred after every chemotherapy session. Finally, he died after 6 months after first admission. Double-hit lymphoma/triple-hit lymphoma has previously been reported to present with an aggressive clinical course. In the present case, co-existence of IGH/CCND1, IGH/MYC, and IGH/BCL2 is very rare. Further clinical and biological investigations are necessary to establish an optimal treatment strategy.

Background: Sarcopenia, the loss of muscle mass, has been recognized as a prognostic factor for cancer patients. For example, low body mass index (BMI) was reported to be a risk of poor overall survival (OS) among allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. However, low BMI was not associated with high non-relapse mortality (NRM) rate, and BMI may not directly reflect the physical condition. (Bone Marrow Transplant. 2014;49:1505-12). To evaluate the clinical impact of the muscle volume on the prognosis of allo-HSCT recipients, other biomarkers that directly reflect muscle mass may be warranted. Urinary creatinine excretion (UCE) has been reported to estimate muscle mass and have prognostic value for kidney transplant patients (Transplantation. 2008;86:391-8.). There is no report to evaluate clinical impact of UCE on the prognosis of allo-HSCT recipients. Therefore, we retrospectively analyzed the association between pre-transplant UCE and the transplant outcomes. Methods: We included 173 adult patients with acute myeloid leukemia (AML) in complete remission (CR) who underwent first allo-HSCT from 2006 to 2017 at our institute and measured UCE before allo-HSCT. Concerned the possibility of urine storage failure, two patients with low total daily urine volume ( We used receiver operating characteristics curve in order to determine the cutoff value of the WA-UCE and classified the patients into the high and low WA-UCE group. We evaluated transplant outcomes such as OS, progression-free survival (PFS), NRM, and cumulative incidence of relapse (CIR) between two groups. Results: The median age at allo-HSCT was 52 (range, 18-73) and there were more male patients (n=111) than female patients (n=60). Regarding cytogenetic risk, 15 (9.1%), 112 (65.8%), and 38 (23.0%) were categorized as favorable, intermediate, and poor risk, respectively (There were five patients without cytogenetic data). The median follow-up period of survivors was 704 (range, 9 to 3,857) days. We defined the cutoff value of the weight adjusted UCE as 148 μmol/kg/day in male and 128 μmol/kg/day in female. Among 171 patients, 90 patients (male = 59, female = 31) were in the high WA-UCE group and 81 patients (male = 52, female = 29) were in the low WA-UCE group. We found no significant differences between two groups in terms of the number of relapse before allo-HSCT, cytogenetic risks, conditioning regimens, hematopoietic cell transplantation comorbidity index, donor-recipient HLA matching, donor source, or estimated glomerular filtration rate. On the other hand, patient's age at allo-HSCT was significantly younger (low vs. high WA-UCE group: median, 53 [range, 18 - 73] vs. 48 [range, 19 - 68] years, P = 0.02) and BMI was lower (low vs. high WA-UCE group: median, 22.3 [range, 15.4 - 38.8] vs. 21.9 [range, 15.4 - 29.3] kg/m2, P = 0.003) in high WA-UCE group. In univariate analysis, we observed a significant difference in OS, PFS, and NRM between two groups (low vs. high WA-UCE group: 1-year OS, 60.1% vs. 80.9%, P < 0.01; 1-year PFS, 54.1% vs. 70.9%, P = 0.02; 1-year NRM, 24.8% vs. 12.3%, P = 0.02) (Figure1). On the other hand, there was no significant difference in 1-year CIR between two groups (low vs. high WA-UCE group: 21.1% vs. 16.8%, P = 0.63). In our cohort, the low BMI (< 18.5 kg/m2) was not significantly associated with OS, PFS, CIR, and NRM (low vs. high BMI group: 1-year OS, 77.6% vs. 69.9%, P = 0.51; 1-year PFS, 74.1% vs. 60.9%, P = 0.45; 1-year CIR, 14.8% vs. 19.5%, P = 0.02, 1-year NRM, 11.1% vs. 19.5%, P = 0.70) In multivariate analysis, the low WA-UCE was an independent risk factor for OS (Hazard ratio (HR) [95% confidence interval (CI)]; 2.29 [1.38 - 3.80], P < 0.01), PFS (HR [95% CI]; 1.76 [1.11 - 2.79], P = 0.02), and NRM (HR [95% CI]; 2.22 [1.13 - 4.36], P = 0.02) (table1). Conclusion: In allo-HSCT adult recipients with AML in CR, low WA-UCE before transplantation was associated with poor prognosis, which related to high NRM within 1 year. WA-UCE can be an independent, objective, simple, and reliable biomarker for evaluating muscle mass and predicting transplant outcome. Disclosures No relevant conflicts of interest to declare.

Background Myelodysplastic syndromes (MDS), commonly seen in elderly patients, represent a heterogeneous group of clonal hematopoietic stem cell disorders caused by the accumulation of gene mutations. By contrast, congenital bone marrow failure syndromes and genetic predispositions associated with MDS are known in pediatric patients. However, little is known about the pathogenesis of MDS in adolescent and young adult (AYA) patients. Previous reports showed the patients with MDS aged under 40 or 41.5 years at allo-HSCT were associated with good survival compared to those among the older population (N Engl J Med. 2017;376:536-547, Blood. 2017;129:2347-2358). However, AYA-MDS is rare, and its clinical features and genetic abnormalities have not been analyzed enough. It is suspected that the clinical and genetic features of AYA-MDS patients might be different from those of elderly patients or pediatric patients. Therefore, we investigated the gene abnormalities of AYA-MDS patients and aimed to elucidate the genetic characteristics associated with the good outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT). We analyzed the patients younger than 50 years of age in order to reduce the variation of patient-related factors. Methods We analyzed the outcomes of all consecutive patients aged under 50 years who were diagnosed with MDS or acute myeloid leukemia evolving from MDS in our hospital between January 2005 and July 2018. The study was approved by the institutional review board, and patients gave written informed consent for the study, according to the Declaration of Helsinki. Cytogenetic analysis and genomic DNA extraction were carried out using diagnostic bone marrow samples. We performed targeted next-generation sequencing to identify mutations in 68 driver genes using AmpliSeq for Illumina Myeloid Panel and On-Demand Panel on the MiniSeq system (Illumina). Gene variants were detected by in-house analysis pipeline. Overall survival (OS) was analyzed for all patients, and the Kaplan-Meier survival curve was used to assess OS using the log-rank test. Additionally, the cumulative incidence of relapse (CIR) was analyzed for patients who underwent allo-HSCT. Gray's test was used to evaluate the CIR. Results A total of 85 patients with MDS aged under 50 years (U40 between 15 and 39 years old: N=37, 40s between 40 and 49 years old: N=48) were analyzed. The median follow-up time of survivors was 2,041 days (range 176-5,085). There were no significant differences in patient characteristics between U40 and 40s. The 3-year OS of U40 were superior to 40s (79.9% vs. 58.1%, P=0.018), especially lower risk IPSS categories (3-year OS, 95.5% vs. 50.8%, P=0.002). In total, 69 of 85 patients (U40: N=31, 40s: N=38) had undergone allo-HSCT. U40 patients had lower percentage of bone marrow blasts at just before HSCT than 40s patients (over 10%, 12.9% vs. 36.8%, P=0.048), and better 3-year OS from HSCT in lower-IPSS (88.8% vs. 53.8%, P=0.024); but not in higher-IPSS (45.0% vs. 43.2%, P=0.834). In this cohort, at least one driver mutation was detected in 61% of allo-HSCT recipients. Frequently mutated genes (more than 10%) were ASXL1 and RUNX1; however, both of the genes did not have significant impact on the outcomes. While, only one patient in 40s had TP53 mutation. We detected 0.8 (range 0-3) and 1.8 (range 0-6) mutations at average in U40 and 40s, respectively (P=0.06). The proportions of the patients without any gene mutations were 52% in U40 and 30% in 40s. Transplanted patients with 0 or 1 mutation showed lower relapse rate than those with 2 or more mutations (3-year CIR, 23.3% vs. 45.2%, P=0.049). Conclusions The clinical outcomes of U40 patients with MDS were favorable than those in the 40s, especially in lower disease risk. The number of driver mutations in U40 tended to be lower than that in 40s. MDS in adult is regarded as a stem-cell aging disease with gene mutations; however, MDS-associated mutations were not detected in the half of U40. Moreover, TP53 mutation that is associated with extremely poor posttransplant survival was not detected in U40 patients. MDS patients with less than 2 mutations showed lower relapse rate, which maybe indicate genetic mutations have a great impact on transplant outcomes between 15 and 49 years old. Disclosures No relevant conflicts of interest to declare.

Background Constitutional partial trisomy 8 mosaicism (CT8M) is a congenital chromosomal abnormality with an estimated occurrence rate as one out of 25,000-50,000 pregnancies. CT8M has a wide variability in physical manifestation ranging from apparently normal to severe disablement. However, diagnosis of CT8M in adult without physical abnormality is difficult . Acquired trisomy 8, which is restricted to the malignant cells, is one of the most common chromosomal abnormalities in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), and clinical implication of carrying isolated trisomy 8 is considered as intermediate cytogenetic risk in MDS. However, isolated trisomy 8 without morphological dysplastic features is not definitive evidence for MDS. 15 to 20% of trisomy 8 in MDS are supposed to be derived from CT8M. We therefore diagnosed CT8M patients among patients with cytopenia and analyzed clinical and genetic features to uncover the association with MDS. Methods . Clinical features including cytogenetic analysis were analyzed regularly. Genomic DNA was extracted from whole PB cells or BM mononuclear cells. We performed targeted next-generation sequencing to identify mutations in 68 driver genes of myeloid neoplasms using AmpliSeq for Illumina Myeloid Panel and On-Demand Panel on the MiniSeq system (Illumina). Gene variants were detected by in-house analysis pipeline. The study was approved by the institutional review board and patients gave written informed consent for the study. Results We identified nine CT8M patients with cytopenia.They comprised 3 males and 6 females at a median age of 56 years (range 24-84 years) (Table). All the patients carried no physical abnormality nor conspicuous phenotypic features. Four patients (Patient #3, #4, #6 and #7) did not show apparent morphological dysplasia at the initial BM examination, and they were not diagnosed as MDS. Their cytopenia has not been exacerbated until now without any treatment, and the duration of stable cytopenia was from 2 to 12 years in these patients. By contrast, five patients with CT8M were diagnosed as MDS . Two patients (#5 and #8) were diagnosed as MDS-single lineage dysplasia (SLD), and their cytopenia has not become worse without any treatment for about 4 years. Other three patients diagnosed as MDS-multilineage dysplasia (MLD) showed various clinical courses. Patient #1 was treated with azacitidine and maintains complete hematological improvement after 34 courses of the treatment. Patient #2 was treated with erythropoietin stimulating agent and azacytidine but developed to AML 3 years after initial diagnosis but leukemic blasts has del(20), not +8. Patient #9 developed advanced pancytopenia in 3 months from initial diagnosis and received red blood cell transfusion regularly. Gene mutations were detected in five out of nine patients with CT8M. In three patients, gene mutations were detected at high (20 to 50%) variant allele frequency (VAF). Patient #2 who was analyzed at the AML phase had gene mutations of SRSF2, SF3B1, STAG2 and NOTCH1. BM sample from patient #9 showed ASXL1 mutation and two TET2 mutations. Patient #4 who did not show apparent myelodysplasia had a high VAF ASXL1 mutation, indicating clonal idiopathic cytopenias of undetermined significance. Two patients had low (2 to 5%) VAF mutations; patient #1 was analyzed after 34 courses of azacitidine had a TET2 mutation; patient #5 with MDS-SLD had a WT1 mutation and two PHF6 mutations. Four patients (#3, #6, #7 and #8) did not have any mutations. The clinical and genetic features showed that CT8M with cytopenia without MDS-related mutations were under 56 years old and did not develop to MDS or stayed at MDS-SLD. Patients with low VAF mutations were also stable. By contrast, patients with advanced diseases gained multiple MDS-related gene mutations with high VAF. One patient without dysplasia had a high VAF ASXL1 mutation. All the patients with gene mutations were age of 56 to 84 years. Conclusion Our results indicated that isolated trisomy 8 may cause cytopenia, but the cytopenia is not exacerbated without MDS-related driver gene mutations. CT8M patients with cytopenia might get gene mutations gradually with age, which leads to MDS or AML. Disclosures No relevant conflicts of interest to declare.

[Background] Philadelphia chromosome positive (Ph+) leukemia is characterized by highly proliferative nature and clone instability that evokes the emergence of mutated clones, including BCR-ABL1 T315I mutated clone. Established evidence on the use of tyrosine kinase inhibitors (TKIs) after allogeneic hematopoietic stem cell transplantation (HSCT) is still lacking. The use of second-generation TKIs as a maintenance treatment after HSCT has been studied, and it is expected that their use would improve the prognosis by suppressing recurrence. The advent of ponatinib (PON), a potent inhibitor of tyrosine kinase including T315I mutated BCR-ABL1, is expected to improve clinical outcome of Ph+leukemia. However, there are few reports of a maintenance treatment using PON after HSCT. [Methods] We retrospectively reviewed data of 13 patients (pts) who received PON for Ph+leukemia after HSCT while in hematological complete remission (CR) between April 1, 2016 and July 15, 2019. Prophylactic treatment (Pro) was defined as post-transplant administration of PON while in minimal residual disease (MRD) negative CR. Pre-emptive treatment (Pre) was defined as starting PON when the bcr-abl transcript was detected by either quantitative or nested qualitative PCR after HSCT. ABL1 mutation was analyzed through the direct sequencing method. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events version 5.0. Overall survival (OS) was estimated using Kaplan-Meier method. Non-relapse mortality (NRM) and cumulative incidence of hematological relapse (CIR) were calculated using Gray's test. This study protocol was approved by the ethics committee of Tokyo Metropolitan Komagome Hospital. [Results] Underlying diseases were Ph+ALL in 8 pts (5 in CR, 3 in non-CR at HSCT), CML in 5 (all in second chronic phase). ABL1 mutations were analyzed in 12 pts and T315I mutation was detected in 4 pts with Ph+ALL and 2 with CML. Furthermore, compound mutations (CMs) in BCR-ABL1 were detected in 4 pts before HSCT. PON was used in 6 only after HSCT, and in 7 both before and after HSCT. During the median observation after HSCT of 584 days (range, 116-1,110) for survivors, no vascular occlusion event occurred. With regard to adverse events (AEs), grade 3 AEs occurred in 2 pts (15.4%) and no grade 4 AE was observed. Two had liver dysfunction and one of them discontinued PON due to grade 3 abnormalities in liver function tests. One suffered from grade 3 thrombocytopenia. Four had skin rashes lower than grade 3 that were indistinguishable from skin graft-versus-host disease, and all of them resolved through topical steroid therapy. Of all, 6 were in Pro group and 7 were in Pre group. The initial dose of PON was median 15mg (range 45mg/twice a week - 15mg/day) in Pro and median 30mg (range, 15-45mg) in Pre. The median days from HSCT to the start of PON was 107 days (range, 32-174) in Pro and 208 days (range, 50-364) in Pre. The median duration of PON treatment was 297 days (range, 20-699) in Pro and 188 days (range, 5-608) in Pre. At final observation in Pro group, 2 pts relapsed and died during the salvage therapy, 1 pt discontinued PON due to hepatic adverse event, and 3 pts were still on PON. Meanwhile, in Pre group, 5 pts achieved MRD negative CR after PON administration (1 pt also received donor lymphocyte infusion and stop PON due to liver dysfunction, 1 discontinued PON by the patient's request, and 3 of them were still on PON). One pt with CM relapsed but achieved CR through salvage therapy and 1 pt with low performance status (KPS 60) died at home of unknown cause six days after taking PON 30mg daily. For all the 13 pts receiving PON maintenance therapy, OS was 74.6% (95%CI; 39.8-91.1), CIR was 23.1% (95%CI; 5.1-48.5), and NRM was 7.7% (95%CI; 0.4-30.6) at 1 year after transplant (Figure 1). Two out of 4 pts with CMs (V299L/F317L and E255K/T315I/F317L) remains in MRD negative CR. The other 2 with CMs (E255K/T315I and D276G/T315I) had progressed to hematological relapse, suggesting the resistance to PON. In contrast, only one out of 9 without CMs relapsed on PON treatment. [Conclusion] Our results suggested that post-transplant maintenance treatment using PON was tolerable in the majority of patients with Ph+leukemia, although the optimal dose or the initiation strategy (Pre or Pro) are still undetermined. Furthermore, some patients with T315I-inclusive CMs seemed to be resistant to PON. The longer observation in a larger cohort is warranted. Disclosures No relevant conflicts of interest to declare.

[Background] Cytomegalovirus (CMV) disease is a major complication after allogeneic stem cell transplantation (SCT). However, mechanisms of adoptive immunity against CMV are not fully elucidated. Recently, high-throughput next-generation sequencing (NGS) technology made it possible to shed light on the detailed and comprehensive landscape of T-cell receptor (TCR) repertoire. In this study, we analyzed TCR repertoire of CMV-specific cytotoxic T-cells (CMV-CTLs) in patients who suffered from CMV reactivation after SCT to clarify the diversity and dynamics of CMV-specific T-cell immunity. [Methods] We sequentially collected peripheral blood mononuclear cells from patients with HLA-A*24:02 who received SCT in our institution. Samples were collected weekly or every two weeks from their neutrophil engraftment until approximately 100 days after SCT. CMV reactivation was evaluated weekly with CMV antigenemia test. CD8 and CMV pp65 tetramer positive cells were sorted and unbiased next-generation sequencing-based analyses of TRBV/TRBJ gene segments were performed at the timing of CMV reactivation in 16 patients, and TRA gene segments were also analyzed in 10 patients. In addition, TCR beta repertoires after 2-4 weeks were analyzed in 12 patients. In the 12 patients, the dynamics of TCR repertoire diversity and proportional changes of each clone were assessed. We evaluated the diversity by Shannon-Weber index, and we defined TCR beta clonotypes found in two or more patients using the same TRBV/TRBJ gene segments and CDR3 amino acid sequences as public. This study was approved by the ethics committee of Tokyo Metropolitan Komagome Hospital. [Results] Among 16 patients, 11 received bone marrow, 3 received peripheral blood stem cells, and 2 received cord blood transplant. Underlying diseases were acute myeloid leukemia in 7, acute lymphoblastic leukemia in 7, and myelodysplastic syndromes in 2 patients. Median age at SCT was 50 years old (range: 20-71). Median duration from SCT to first CMV reactivation was 39 days (range: 16-55) and 7 patients (43.8%) were administered systemic corticosteroid at the time of reactivation (prednisolone 10-30mg/day). Median peripheral blood CMV-CTLs count at that time was 29.47/uL (range: 4.65-229.6). In most patients TCR beta repertoire of CMV-specific CTLs when CMV reactivated was highly skewed (median Shannon-Weber index was 1.44 [range: 0.542-3.164]). TCR alpha and beta were analyzed together in 10 patients and their diversity correlated well (p [Conclusion] TCR repertoire of CMV-CTLs at the time of CMV reactivation after SCT is highly oligoclonal and frequently shared among different patients, but can dynamically change in a short period in some patients. Functional analyses of the dominant TCRs to understand their reactivity against CMV epitope and elucidation of the clinical significance and developmental mechanisms of clone shift are strongly warranted. Figure Disclosures Kitaura: Repertoire Genesis Inc.: Employment. Suzuki:Repertoire Genesis Inc.: Equity Ownership.

A 34-year-old man, working at a park in Tokyo, Japan, was repeatedly bitten by mosquitoes while cutting grass. He was hospitalized with sudden fever, fatigue, and weakness. He was eventually diagnosed with dengue virus infection, detected using reverse transcription polymerase chain reaction for the genome and by the presence of nonstructural protein 1 in his peripheral blood. Symptomatic treatments such as acetaminophen for the fever were not effective. Moreover, peripheral blood examination showed drastically decreased white blood cells and platelets, as well as marked elevations of ferritin and soluble interleukin 2 receptor. Furthermore, bone marrow examination revealed increased macrophages with hemophagocytosis. Dengue infection with hemophagocytic lymphohistiocytosis (HLH) was ultimately diagnosed. Half-dose steroid pulse therapy for three days dramatically reduced his temperature, thereby ameliorating physical symptoms and restoring normal peripheral blood data. He was discharged 12 days after admission. Dengue infection with HLH is rare and this is the first report, to our knowledge, of domestic dengue infection with HLH in Japan. Early steroid therapy may be effective in such cases.