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Comparative studies between total body irradiation (TBI)-based and busulfan-based myeloablative conditioning (MAC) regimens for cord blood transplantation (CBT) have been limited. We retrospectively analyzed the results of single-unit CBT in 333 adult patients who received either TBI-based (

By December 2021, about 80% of people over the age of 12 had been vaccinated in Japan, and almost all people were vaccinated with the mRNA vaccine. We investigated here the anti-spike protein antibody titer at the time of breakthrough infection of SARS-CoV-2 omicron. A total of 32 SARS-CoV2 omicron breakthrough infection was included in the study. The median antibody titer at breakthrough infection was 776 AU/mL overall, of which the median antibody titer of BNT162b2 vaccinated was 633 AU/mL and that of mRNA-1273 vaccinated was 9416 AU/mL. This result suggests that low levels of antibody titers 6 months after vaccination do not provide sufficient antibodies to prevent the omicron variant breakthrough infection, which may occur with a higher anti-spike antibody titer after vaccination with mRNA-1273. However, antibody titers in some patients were comparable to those immediately after the second vaccination with either mRNA vaccine.

An intensified myeloablative conditioning regimen, involving the addition of granulocyte colony-stimulating factor (G-CSF)-combined high-dose cytarabine (12 g/m2) to standard total body irradiation and cyclophosphamide, has been performed for adult patients with myeloid malignancies in single-unit cord blood transplantation (CBT) since 1998 in our institute. We update the results of CBT, as the first allogeneic hematopoietic cell transplantation after this conditioning regimen, in 169 patients with a median long-term follow-up of 10.4 years. The median age was 43 years (range, 16 to 59 years). Ninety-four patients (56%) were in non-remission at the time of CBT, and 124 patients (73%) were acute myeloid leukemia. The median cryopreserved cord blood total nucleated cell dose and CD34+ cell dose was 2.40 × 107/kg and 0.93 × 105/kg, respectively. The cumulative incidence of neutrophil recovery at 42 days was 94.4% (95% confidence interval [CI]: 88.6–97.3%). Among the whole cohort, 105 patients were still alive at the end of the study period. The cumulative incidences of relapse and non-relapse mortality at 10 years were 26.0% (95% CI: 19.5–33.0%) and 16.9% (95% CI: 11.4–23.4%), respectively. There was an overall survival probability of 62.5% (95% CI: 54.3–69.7%) at 10 years. Higher disease risk index alone significantly affected higher overall mortality (hazard ratio 2.21, P = 0.003) in multivariate analysis. These outcomes demonstrate that G-CSF-combined myeloablative conditioning could have favorable long-term remission rates for adult patients with myeloid malignancies undergoing single-unit CBT.

Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is one of the most serious complications to occur early after allogeneic hematopoietic cell transplantation (HCT). However, detailed data on VOD/SOS after cord blood transplantation (CBT) are not available. The objective of this retrospective study was to evaluate the incidence, risk factors, and clinical impact of VOD/SOS after single-unit unrelated CBT for adult patients at our institution. We retrospectively evaluated the incidence, risk factors, and outcomes of VOD/SOS after 390 single-unit unrelated CBTs performed in 332 adults under a prophylactic strategy of ursodeoxycholic acid (UDCA) and i.v. heparin at our institution between 1998 and 2021. VOD/SOS was observed in 24 of the 390 CBTs. The cumulative incidence of VOD/SOS was 5.9% at 30 days and 6.2% at 100 days after CBT. Multivariate analysis showed that cryopreserved CD34

The intestinal microbiota plays a fundamental role in the development of host innate immune cells, such as monocytes, dendritic cells (DCs), and natural killer (NK) cells. We examined the association between intestinal microbiota and subsequent immune reconstitution of circulating monocyte, DC, and NK cell subsets in 38 adult patients undergoing single-unit cord blood transplantation (CBT). A higher diversity of intestinal microbiota at 1 month was significantly associated with higher counts of plasmacytoid DCs at 7 months after CBT, as measured by the Chao1 index. Principal coordinate analysis of unweighted UniFrac distances showed significant differences between higher and lower classical monocyte reconstitution at 7 months post-CBT. The families Neisseriaceae, Burkholderiaceae, Propionibacteriaceae, and Coriobacteriaceae were increased in higher classical monocyte reconstitution at 7 months post-CBT, whereas the family Bacteroidaceae was increased in lower classical monocyte reconstitution at 7 months post-CBT. These data show that intestinal microbiota composition affects immune reconstitution of classical monocyte and plasmacytoid DCs following single-unit CBT.

Vancomycin (VCM) is frequently used for neutropenic patients undergoing cord blood transplantation (CBT). We retrospectively examined the relationship between VCM trough levels and the efficacy and toxicity in 122 adult patients undergoing CBT in our institute. The median initial dose of VCM based on body weight was 9.1 mg/kg/dose (range, 6.0-22.6 mg/kg/dose). The median initial trough level of VCM for all patients was 4.50 µg/mL (range, 1.20-24.05 µg/mL), at a median of 3 days (range, 2-6 days) after VCM administration. The cumulative incidence of acute kidney injury (AKI) was 19% at 30 days after VCM administration. A higher median trough level of VCM during the first 7 days was significantly associated with the development of AKI in the multivariate analysis (Hazard ratio: 1.28

Severe bacterial infections are a serious problem after cord blood transplantation (CBT). Colonization with multidrug-resistant Gram-negative rods (MRGNR) is associated with increased morbidity and mortality after allogeneic hematopoietic cell transplantation. However, its impact on outcomes after CBT is unclear. We aim to explore the impact of colonization with MRGNRs in adult patients undergoing CBT. We retrospectively analyzed 145 adult patients who received single-unit CBT in our institute. As a standard practice in our institute, all patients were screened for colonization with MRGNR by oral cavity swabs, urine, and stool specimens between the day of admission for CBT and the day of discharge or day 100 after CBT. There were 62 incidents of colonization with MRGNR in 52 patients, of which 25 involved Stenotrophomonas maltophilia, 19 multidrug-resistant Pseudomonas spp., and 18 extended-spectrum beta-lactamase-producing Enterobacteriaceae. On multivariate analysis, MRGNR persistence significantly affected increase in non-relapse mortality (NRM) (hazard ratio [HR], 8.96; 95% CI 1.85-43.46; P = 0.006) and the subsequent development of bloodstream infection due to MRGNR (HR 11.82; 95% CI 2.15-64.87; P = 0.004), but not MRGNR clearance, compared with non-colonized patients. These data suggest that persistent colonization with MRGNR is significantly associated with higher NRM in CBT for adults.

This study investigated the safety, efficacy, and immunological influence of allogeneic umbilical cord-derived mesenchymal stromal cells (IMSUT-CORD) processed in serum-free medium and cryoprotectant, for treating steroid-resistant acute graft-versus-host disease (aGVHD). In a phase I dose-escalation trial, IMSUT-CORD were infused intravenously twice weekly over two cycles with up to two additional cycles. Four patients received a dose of 1 × 10

We retrospectively evaluated the optimal time and threshold of absolute lymphocyte count (ALC) recovery as a prognostic factor in 174 adult patients who received single-unit cord blood transplantation (CBT) at our institute. We analyzed the impact of ALC ≥300, ≥600, and ≥900/μl by 30 and 60 days on transplant outcomes. Multivariate analysis showed that only ALC ≥300/μl at 60 days was significantly associated with overall mortality (hazard ratio, 0.24

The incidence of an active tuberculosis infection after allogeneic hematopoietic cell transplantation is high. We herein report the case of a patient with acute myeloid leukemia after cord blood transplantation (CBT). On day 36 after CBT, the patient developed fever, and a computed tomography scan on day 36 showed mild thickening of the wall of the gallbladder. Subsequently, a sputum specimen and a blood culture returned positive for the growth of Mycobacterium tuberculosis. After 2 months of administering combination therapy, both the symptoms and gallbladder findings improved. We therefore describe a case of disseminated tuberculosis with the gallbladder mimicking acute cholecystitis in a CBT recipient.

Micafungin (MCFG) is an echinocandin antifungal drug used for prophylaxis and treatment of fungal infections after allogeneic hematopoietic cell transplantation (HCT). However, its efficacy and safety in patients undergoing cord blood transplantation (CBT) has not been clarified. We retrospectively analyzed the efficacy and safety of MCFG in 92 adult patients undergoing CBT in our institute. Of the entire cohort, 83 patients (90%) received MCFG for empirical or preemptive therapy. Documented breakthrough fungal infection occurred in 2 patients during MCFG treatment. Among the 49 patients who received MCFG as empirical therapy for febrile neutropenia, 41 (84%) patients had resolution of fever during neutropenia. Elevation of serum levels of hepatobiliary parameters during MCFG treatment was commonly observed, but grade 3 or higher elevation was rare. We also compared the efficacy and safety of 2 different initial daily doses of MCFG (150 mg vs. 300 mg). There were no significant differences of efficacy and safety between the two groups. These data suggest that MCFG was effective and safe for adult patients undergoing CBT. The optimal daily dose of MCFG treatment is a matter of future investigation for adult patients undergoing CBT.

The introduction of the prophylactic use of antifungal drugs caused the increased occurrence of invasive fungal infections due to previously rare molds, such as fusariosis, after allogeneic hematopoietic stem cell transplantation. We herein report the case of a patient with diffuse large B-cell lymphoma who developed fungemia due to Fusarium solani during liposormal amphotericin B on day 25 after cord blood transplantation (CBT). Because Fusarium species might differ in virulence and drug susceptibility, the sequencing of the internal transcribed spacer region of the ribosomal RNA gene accurately identified Fusarium solani to be the cause of fungemia at the species level. This case highlights Fusarium solani as the cause of fungemia in a patient under liposormal amphotericin B treatment after CBT.

This study was performed to assess the utility of tumor-derived fragmentary DNA, or circulating tumor DNA (ctDNA), for identifying high-risk patients for relapse of acute myeloid leukemia and myelodysplastic syndrome (AML/MDS) after undergoing myeloablative allogeneic hematopoietic stem cell transplantation (alloSCT). We retrospectively collected tumor and available matched serum samples at diagnosis and 1 and 3 months post-alloSCT from 53 patients with AML/MDS. After identifying driver mutations in 51 patients using next-generation sequencing, we designed at least 1 personalized digital polymerase chain reaction assay per case. Diagnostic ctDNA and matched tumor DNA exhibited excellent correlations with variant allele frequencies. Sixteen patients relapsed after a median of 7 months post-alloSCT. Both mutation persistence (MP) in bone marrow (BM) at 1 and 3 months post-alloSCT and corresponding ctDNA persistence (CP) in the matched serum (MP1 and MP3; CP1 and CP3, respectively) were comparably associated with higher 3-year cumulative incidence of relapse (CIR) rates (MP1 vs non-MP1, 72.9% vs 13.8% [P = .0012]; CP1 vs non-CP1, 65.6% vs 9.0% [P = .0002]; MP3 vs non-MP3, 80% vs 11.6% [P = .0002]; CP3 vs non-CP3, 71.4% vs 8.4% [P < .0001]). We subsequently evaluated whether subset analysis of patients with 3 genes associated with clonal hematopoiesis, DNMT3A, TET2, and ASXL1 (DTA), could also be helpful in relapse prediction. As a result, CP based on DTA gene mutations also had the prognostic effect on CIR. These results, for the first time, support the utility of ctDNA as a noninvasive prognostic biomarker in patients with AML/MDS undergoing alloSCT.

The different effects of pre-engraftment syndrome (PES) and acute graft-versus-host disease (aGVHD) on outcomes after cord blood transplantation (CBT) are unclear. We retrospectively evaluated the impact of PES and aGVHD on relapse and survival after single-unit CBT in 138 adult patients with hematologic malignancies at our institution between 2004 and 2016. Multivariate analysis demonstrated that development of grade III-IV aGVHD, particularly with gut or liver involvement, significantly contributed to higher nonrelapse mortality (P.001), but PES and grade II-IV aGVHD did not. In subgroup analyses of underlying disease type, the development of PES had a significant effect on decreased relapse (P = .032) and better disease-free survival (DFS) (P = .046) in patients with acute myelogenous leukemia (AML). These data suggest that PES is associated with a reduced relapse rate and better DFS in AML, indicating that the early immune reaction before neutrophil engraftment may provide a unique graft-versus-leukemia effect after single-unit CBT.

T memory stem cells (TSCMs) are a subset of primitive T cells capable of both self-renewal and differentiation into all subsets of memory and effector T cells. Therefore, TSCMs may play a role in immune reconstitution and graft-versus-host disease (GVHD) in patients receiving allogeneic haematopoietic cell transplantation (HCT). We conducted a cross-sectional study to evaluate the proportions, absolute counts, phenotypes and functions of TSCMs in 152 adult patients without disease recurrence at least 12 months after undergoing HCT. CD4+ TSCMs were negatively correlated with number of months after transplantation in HCT patients that received cord blood transplantation, but not in patients that received bone marrow transplantation or peripheral blood stem cell transplantation. The proportions and absolute counts of CD4+ TSCMs and expression levels of inducible co-stimulator (ICOS) in CD8+ TSCMs were significantly higher in patients with mild and moderate/severe cGVHD compared to patients without cGVHD. These data suggested that, more than 12 months after allogeneic HCT, the kinetics of CD4+ TSCMs were dependent on the type of donor source, and further that CD4+ TSCMs and ICOS levels in CD8+ TSCMs were associated with cGVHD.

Increased red blood cell (RBC) transfusion requirements are associated with morbidity and mortality after allogeneic hematopoietic cell transplantation. However, its impact on the outcomes after cord blood transplantation (CBT) is unclear. We retrospectively analyzed the data of 278 adult patients who received single-unit CBT in our institute. The median number of RBC transfusions for each patient was 12 units (range, 4-66) by day 30 and 14 units (range, 4-70) by RBC engraftment. Sex, cord blood CD34+ cell dose, cytomegalovirus serostatus, total body irradiation dose in the conditioning regimen, ABO blood group incompatibility, and pre-CBT RBC transfusion requirements were significantly associated with the number of RBC transfusion units in the linear regression analysis. In the multivariate analysis, RBC transfusion ≥18 units by day 30 was significantly associated with higher overall mortality (hazard ratio, 1.86; P = 0.018). These data suggested that early RBC transfusion burden was significantly associated with overall mortality in adult patients undergoing single CBT. Early RBC transfusion burden might be a surrogate marker for poor outcomes after single CBT.

Although varicella zoster virus (VZV) disease is a common complication after allogeneic hematopoietic cell transplantation (HCT), research into the long-term incidence of VZV disease in adults receiving cord blood transplantation (CBT) has been limited. The objective of this study was to evaluate the incidence, risk factors, and clinical impact of VZV disease after CBT with long-term follow-up in our institution. We retrospectively analyzed the data for 156 adult patients who received single-unit CBT at our institution between 2007 and 2020 and who achieved neutrophil engraftment and survived at least 100 days without recurrence of the underlying disease. VZV disease occurred in 61 patients at a median of 608 days (range, 36 to 4090 days) after CBT. The cumulative incidence of VZV disease was 14% (95% confidence interval [CI], 9% to 20%) at 1 year post-CBT and 40% (95% CI, 31% to 48%) at 5 years post-CBT. Multivariate analysis identified the cessation of antiviral prophylaxis as an independent risk factor for an elevated risk of VZV disease (hazard ratio, 15.65; 95% CI, 6.59 to 37.21; P.001). The cumulative incidence of VZV disease was significantly lower in the long-term antiviral prophylaxis group (who received prophylaxis for approximately 1 year after CBT or to the end of immunosuppressive therapy) compared with the short-term antiviral prophylaxis group (who received prophylaxis for 35 days after CBT) (P = .005). Among the patients who developed VZV disease, the median time to onset of VZV disease was significantly delayed in the long-term antiviral prophylaxis group compared with the short-term antiviral prophylaxis group (694 days versus 130 days; P.001), but the median onset of VZV disease after the cessation of antiviral prophylaxis was not significantly different between the 2 groups (166 days versus 95 days; P = .087). These data demonstrate that the long-term incidence of VZV disease is relatively high in adult patients undergoing CBT. Given that the incidence of VZV disease remained high after the cessation of antiviral prophylaxis, additional interventions, such as recombinant zoster vaccine administration, could be required to prevent VZV disease in long-term adult survivors after CBT.

INTRODUCTION After the first appearance of peripheral blood neutrophils, recipients from adult donor sources have a rapid increase in neutrophil recovery, whereas cord blood transplantation (CBT) recipients have a slow increase. However, the momentum of neutrophil recovery after CBT varies widely among individuals, but optimal methods to evaluate the momentum of neutrophil recovery and their clinical impacts are yet to be clarified. METHODS We retrospectively examined the prognostic effect of the momentum of neutrophil recovery in the last 7 days until neutrophil engraftment, which was calculated by an exponential growth model, after single CBT following myeloablative conditioning for 207 adults. RESULTS Among patients who achieved each hematopoietic lineage recovery by day 100, the momentum of neutrophil recovery, which was represented as a growth constant, was associated with the day of neutrophil engraftment (P

INTRODUCTION The appearance of erythroblasts (EBLs) in peripheral blood occurs in a variety of serious conditions and has been associated with mortality in critically ill patients. However, the incidence, risk factor, and outcomes of EBLs after cord blood transplantation (CBT) remain unclear. METHODS We have investigated the impact of EBLs on transplant outcomes on 225 adult patients who underwent single-unit CBT at our single institute. RESULTS The cumulative incidences of EBL ≥200 × 106 /L and EBL ≥1000 × 106 /L at 60 days after CBT were 17% and 4%, respectively, detected after a median of 35 days and 36.5 days. Multivariate analysis using erythroblastosis as time-dependent covariates demonstrated the significant association of EBL ≥1000 × 106 /L, but not EBL ≥200 × 106 /L, with the development of grade III-IV acute graft-versus-host disease (GVHD, hazard ratio [HR]: 18.56; P

A prior history of cancer was associated with higher non-relapse mortality or overall mortality in patients undergoing allogeneic haematopoietic cell transplantation. Because it is unclear whether the outcomes after cord blood transplantation are influenced by a prior history of cancer, we retrospectively assessed the prevalence and prognostic impact of a prior history of cancer in adult patients undergoing myeloablative single-unit cord blood transplantation in our institute between 2004 and 2020. The univariate analysis showed that a prior history of cancer did not affect the probability of overall survival; the cumulative incidence of relapse; or non-relapse mortality. In the multivariate analysis, prior history of cancer was not associated with overall mortality, relapse or non-relapse mortality. No patients with a prior history of cancer had experienced prior cancer relapse. A prior history of cancer was not associated with non-relapse mortality or overall mortality following single-unit cord blood transplantation.

The availability of alternative donor sources could allow elderly patients to receive allogeneic hematopoietic cell transplantation (HCT). We retrospectively evaluated the outcomes of single-unit cord blood transplantation (CBT) in 1577 patients aged ≥60 years with acute myeloid leukemia (AML) in Japan between 2002 and 2017. In total, 990 (63%) patients were not in complete remission (CR) at the time of CBT. A myeloablative conditioning regimen (52%) and calcineurin inhibitor (CI) + mycophenolate mofetil (MMF)-based graft-versus-host disease (GVHD) prophylaxis (45%) were more commonly used. With a median follow-up for survivors of 31 months, the probability of overall survival and the cumulative incidence of leukemia-related mortality at 3 years was 31% and 29%, respectively. The cumulative incidence of non-relapse mortality (NRM) at 100 days and 3 years were 24% and 41%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute GVHD at 100 days and extensive chronic GVHD at 2 years were 44%, 16%, and 14%, respectively. The cumulative incidence of neutrophil engraftment was 80% at 42 days. Results of multivariate analysis indicated that the following factors were significantly associated with higher overall mortality: performance status ≥1, hematopoietic cell transplantation-specific comorbidity index ≥3, adverse cytogenetics, extramedullary disease at diagnosis, and non-CR status at CBT. By contrast, female sex, HLA disparities ≥2, mycophenolate mofetil-based GVHD prophylaxis, and recent CBT were significantly associated with lower overall mortality. In conclusion, single CBT offers a curative option for AML patients aged ≥60 years with careful patient selection.

Platelet transfusion refractoriness (PTR) is frequently observed after allogeneic hematopoietic cell transplantation (HCT). However, the incidence of and risk factors for PTR, and impact of PTR on transplant outcomes after cord blood transplantation (CBT) have not been fully investigated. We retrospectively analyzed 185 adult patients who received single-unit CBT in our institute. The mean 16-hour corrected count increment (CCI) for the 5840 platelet transfusions was 3.68 × 109/L. Among them, 3196 transfusions (54.7%) were associated with a PTR with 16-hour-CCI

Chronic graft-versus-host disease (cGVHD) is a major cause of late morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Monocytes/macrophages play a central role in inflammation, tissue repair, and fibrosis, which are the main clinical features of cGVHD. Here, we examined the expression levels of activation markers, chemokine receptors, and scavenger receptors for each circulating monocyte subset in 145 patients without disease recurrence at least 12 months after undergoing allogeneic HCT. There were no significant differences in the numbers and the proportions of each monocyte subset between patients without cGVHD and those with mild or moderate/severe cGVHD. Lower expression of CCR5 on classical monocytes, and higher expression of CD204 and lower expression of CX3CR1 on non-classical monocytes were associated with joint, and lung cGVHD, respectively. These data showed that alterations of activation markers and chemokine and scavenger receptors in each circulating monocyte subset were associated with the development of organ-specific cGVHD. Alterations of surface markers in each circulating monocyte subset may be candidate biomarkers for cGVHD.

BCR-ABL1 tyrosine kinase inhibitors (TKIs) are effective agents in the treatment of Philadelphia chromosome-positive leukemia. However, vascular events have developed in some patients receiving each TKI. The perturbation of circulating monocyte subsets and their expressions of chemokine and scavenger receptors are associated with the development of cardiovascular events. Here, we examined the subsets of circulating monocytes and their phenotypes in 51 patients treated with imatinib, nilotinib, and dasatinib, and 11 healthy subjects in our institute. Except for a negative association between the number of classical monocytes and imatinib treatment, the proportions and numbers of monocyte subsets were not significantly associated with TKI treatment. However, chemokine receptors, CCR2, CX3CR1 on classical monocytes, and scavenger receptor, CD204, on intermediate and non-classical monocytes were significantly associated with TKIs. These data demonstrated the relationships between alterations of chemokine and scavenger receptors on different monocyte subsets and the TKI treatments.

Clinical manifestation of high-grade fever and skin rash before neutrophil engraftment, termed pre-engraftment syndrome (PES) or pre-engraftment immune reaction, has been frequently observed after cord blood transplantation (CBT). The pathophysiology of PES is poorly understood, but cytokine storm during the early phase of CBT is thought to be 1 of the main cause of PES. However, the cytokine profiles of PES after CBT are unclear. Therefore, we examined the relationship between serum cytokine profiles and PES in 44 adult patients who received CBT in our institution between February 2013 and June 2016. Serum levels of 21 cytokines, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-17A, IL-17F, IL-18, IL-21, IL-22, IL-23, IL-33, monocyte chemoattractant protein-1, IFN-α, IFN-γ, and TNF-α, were measured by multiplex bead assays using a flow cytometer. The median time until the absolute neutrophil count was >.5 × 109/L was 21 days (range, 15 to 41 days). The cumulative incidence of PES was 79.6% (95% confidence interval, 63.3% to 88.5%) at 60 days after CBT. Serum levels of IL-5 (P = .009) and IL-6 (P = .01) at 2 weeks were significantly higher in patients who developed PES compared with those who did not develop PES. The conversion from naive to effector or central memory phenotype of T cells was observed in PES. These data indicate that elevations of IL-5 and IL-6 around the time of clinical manifestation may be possible biomarkers for PES after CBT.

Low cryopreserved total nucleated cell (TNC) dose in a cord blood (CB) unit has been shown to be associated with engraftment failure and mortality after single-unit cord blood transplantation (CBT) in adults. Although CB banks offer specific characteristics of cryopreserved cell dose, such as TNC, CD34+ cells, and colony-forming unit for granulocyte/macrophage (CFU-GM), the impact of each cell dose on engraftment and outcomes after single-unit CBT in adults remains unclear. We retrospectively analyzed the results of 306 CBTs for 261 adult patients in our institution between 1998 and 2016. The median age was 43 years (range, 16 to 68), the median actual body weight (ABW) was 56.2 kg (range, 36.2 to 104.0), the median ideal body weight (IBW) was 62.3 kg (range, 39.7 to 81.3), the median TNC dose was 2.46 × 107/ABW kg (range, 1.07 to 5.69), the median CD34+ cell dose was .91 × 105/ABW kg (range, .15 to 7.75), and the median CFU-GM dose was 24.46 × 103/ABW kg (range, .04 to 121.81). Among patients who achieved engraftment, the speed of neutrophil, platelet, and red blood cell engraftment significantly correlated with CD34+ cell dose, but not with TNC and CFU-GM dose, based on both ABW and IBW. In multivariate analysis, the incidence of extensive chronic graft-versus-host disease (GVHD) was significantly higher in patients receiving the highest CD34+ cell dose, based on both ABW and IBW. Nevertheless, no cell dose was associated with survival, transplantation-related mortality, and relapse. In conclusion, cryopreserved CD34+ cell dose was the best predictor for hematopoietic recovery and extensive chronic GVHD after CBT. The cryopreserved CD34+ cell dose should be used for unit selection criteria in single-unit CBT for adults.

LPS triggers inflammatory responses; however, the negative regulation of LPS responses in vivo remains poorly understood. CD300f is an inhibitory receptor among the CD300 family of paired activating and inhibitory receptors. We have previously identified ceramide as a ligand for CD300f and shown that the binding of ceramide to CD300f inhibits IgE-mediated mast cell activation and allergic responses in mouse models. Here we identify the critical role of CD300f in inhibiting LPS-induced skin inflammation. CD300f deficiency remarkably enhanced LPS-induced skin edema and neutrophil recruitment in mice. Higher levels of factors that increase vascular permeability and of factors that induce neutrophil recruitment were detected in LPS-injected skin pouch exudates of CD300f-/- mice as compared with wild-type mice. CD300f was highly expressed in mast cells and recruited neutrophils, but not in macrophages, among skin myeloid cells. CD300f deficiency failed to influence the intrinsic migratory ability of neutrophils. Ceramide-CD300f binding suppressed the release of chemical mediators from mast cells and from neutrophils in response to LPS. Adoptive transfer experiments indicated that mast cells mediated enhanced edema in LPS-stimulated skin of CD300f-/- mice, whereas mast cells together with recruited neutrophils mediated robust neutrophil accumulation. Importantly, administering a ceramide antibody or ceramide-containing vesicles enhanced or suppressed LPS-induced skin inflammation of wild-type mice, respectively. Thus, ceramide-CD300f binding inhibits LPS-induced skin inflammation, implicating CD300f as a negative regulator of Toll-like receptor 4 (TLR4) signaling in vivo.

The conditioning regimen used for allogeneic hematopoietic cell transplantation (HCT) must eradicate residual tumor cells and provide sufficient immunosuppression to facilitate donor engraftment. H...

Mucosal-associated invariant T (MAIT) cells are a type of innate lymphocyte and recognize riboflavin (vitamin B2) synthesis products presented by MHC-related protein 1. We investigated long-term reconstitution of MAIT cells and its association with chronic graft-versus-host disease (cGVHD) in a cross-sectional cohort of 173 adult patients after allogeneic hematopoietic cell transplantation. According to donor source, the number of MAIT cells significantly correlated with time after cord blood transplantation (CBT) but not with time after bone marrow transplantation or peripheral blood stem cell transplantation. The number of MAIT cells was significantly lower in patients with cGVHD compared with patients without cGVHD. We also examined the association between MAIT cell reconstitution and gut microbiota as evaluated by 16S ribosomal sequencing of stool samples 1 mo post-CBT in 27 adult patients undergoing CBT. The diversity of gut microbiota was positively correlated with better MAIT cell reconstitution after CBT. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States analysis indicated that amounts of ribB and ribA genes were significantly higher in the microbiomes of patients with subsequent MAIT cell reconstitution after CBT. In conclusion, long-term MAIT cell reconstitution is dependent on the type of donor source. Our data also unveiled an important role for the interaction of circulating MAIT cells with gut microbiota in humans.

Early fluid overload has been associated with poor transplant outcomes after allogeneic hematopoietic cell transplantation. However, its effects on the outcomes after cord blood transplantation (CBT) are unclear. We retrospectively analyzed the data of 227 adult patients who received single-unit CBT in our institute. The cumulative incidence of grade ≥2 fluid overload was 4% at day 30 after CBT with a median onset at 16 days (range, 9-30 days) after CBT. In the multivariate analysis, grade ≥2 fluid overload was significantly associated with higher non-relapse mortality (hazard ratio [HR], 5.73; P = 0.011) and overall mortality (HR, 3.81; P = 0.006). Among the entire cohort, 133 patients were treated with low-dose dopamine (0.5-2 µg/kg/min) with a median time of initiation of low-dose dopamine therapy at 10.5 days after CBT. Use of low-dose dopamine significantly increased daily urine output and decreased body weight. These data suggested that early fluid overload was significantly associated with non-relapse and overall mortality after single CBT. The early intervention of low-dose dopamine to prevent early fluid overload is a matter of future investigation for patients undergoing allogeneic hematopoietic cell transplantations (HCT), particularly for CBT.

Genetic mutation is one of the most powerful prognostic factors for adult patients with acute myeloid leukemia (AML). The FMS-like tyrosine kinase 3 (FLT3) gene mutations, including internal tandem...

Zymosan is a glucan that is a component of the yeast cell wall. Here, we determined the mechanisms underlying the zymosan-induced accumulation of neutrophils in mice. Loss of the receptor CD300b reduced the number of neutrophils recruited to dorsal air pouches in response to zymosan, but not in response to lipopolysaccharide (LPS), a bacterial membrane component recognized by Toll-like receptor 4 (TLR4). An inhibitor of nitric oxide (NO) synthesis reduced the number of neutrophils in the zymosan-treated air pouches of wild-type mice to an amount comparable to that in CD300b-/- mice. Treatment with clodronate liposomes decreased the number of NO-producing, CD300b+ inflammatory dendritic cells (DCs) in wild-type mice, thus decreasing NO production and neutrophil recruitment. Similarly, CD300b deficiency decreased the NO-dependent recruitment of neutrophils to zymosan-treated joint cavities, thus ameliorating subsequent arthritis. We identified phytosphingosine, a lipid component of zymosan, as a potential ligand of CD300b. Phytosphingosine stimulated NO production in inflammatory DCs and promoted neutrophil recruitment in a CD300b-dependent manner. Together, these results suggest that the phytosphingosine-CD300b interaction promotes zymosan-dependent neutrophil accumulation by inducing NO production by inflammatory DCs and that CD300b may contribute to antifungal immunity.