Parameter sensitivities in tilted-pulse-front based terahertz setups and their implications for high-energy terahertz source design and optimization.

Despite the popularity and ubiquity of the tilted-pulse-front technique for single-cycle terahertz (THz) pulse generation, there is a deficit of experimental studies comprehensively mapping out the dependence of the performance on key setup parameters. The most critical parameters include the pulse-front tilt, the effective length of the pump pulse propagation within the crystal as well as effective length over which the THz beam interacts with the pump before it spatially walks off. Therefore, we investigate the impact of these parameters on the conversion efficiency and the shape of the THz beam via systematically scanning the 5D parameter space spanned by pump fluence, pulse-front-tilt, crystal-position (2D), and the pump size experimentally. We verify predictions so far only made by theory regarding the optimum interaction lengths and map out the impact of cascading on the THz radiation generation process. Furthermore, distortions imposed on the spatial THz beam profile for larger than optimum interaction lengths are observed. Finally, we identify the most sensitive parameters and, based on our findings, propose a robust optimization strategy for tilted-pulse-front THz setups. These findings are relevant for all THz strong-field applications in high demand of robust high-energy table-top single-cycle THz sources such as THz plasmonics, high-harmonic generation in solids as well as novel particle accelerators and beam manipulators.

Characteristics of Graft-Versus-Host Disease (GvHD) After Post-Transplantation Cyclophosphamide Versus Conventional GvHD Prophylaxis.

Post-transplantation cyclophosphamide (PTCy) has been shown to effectively control graft-versus-host disease (GvHD) in haploidentical (Haplo) transplantations. In this retrospective registry study, we compared GvHD organ distribution, severity, and outcomes in patients with GvHD occurring after Haplo transplantation with PTCy GvHD prophylaxis (Haplo/PTCy) versus HLA-matched unrelated donor transplantation with conventional prophylaxis (MUD/conventional). We evaluated 2 cohorts: patients with grade 2 to 4 acute GvHD (aGvHD) including 264 and 1163 recipients of Haplo and MUD transplants; and patients with any chronic GvHD (cGvHD) including 206 and 1018 recipients of Haplo and MUD transplants, respectively. In comparison with MUD/conventional transplantation ± antithymocyte globulin (ATG), grade 3-4 aGvHD (28% versus 39%, P = .001), stage 3-4 lower gastrointestinal (GI) tract aGvHD (14% versus 21%, P = .01), and chronic GI GvHD (21% versus 31%, P = .006) were less common after Haplo/PTCy transplantation. In patients with grade 2-4 aGvHD, cGvHD rate after Haplo/PTCY was also lower (hazard ratio [HR] = .4, P < .001) in comparison with MUD/conventional transplantation without ATG in the nonmyeloablative conditioning setting. Irrespective of the use of ATG, non-relapse mortality rate was lower (HR = .6, P = .01) after Haplo/PTCy transplantation, except for transplants that were from a female donor into a male recipient. In patients with cGvHD, irrespective of ATG use, Haplo/PTCy transplantation had lower non-relapse mortality rates (HR = .6, P = .04). Mortality rate was higher (HR = 1.6, P = .03) during, but not after (HR = .9, P = .6) the first 6 months after cGvHD diagnosis. Our results suggest that PTCy-based GvHD prophylaxis mitigates the development of GI GvHD and may translate into lower GvHD-related non-relapse mortality rate.

Broad-Spectrum Antibiotics and Risk of Graft-versus-Host Disease in Pediatric Patients Undergoing Transplantation for Acute Leukemia: Association of Carbapenem Use with the Risk of Acute Graft-versus-Host Disease

Variation in the gastrointestinal (GI) microbiota after hematopoietic cell transplantation (HCT) has been associated with acute graft-versus-host disease (aGVHD). Because antibiotics induce dysbiosis, we examined the association of broad-spectrum antibiotics with subsequent aGVHD risk in pediatric patients undergoing HCT for acute leukemia. We performed a retrospective analysis in a dataset merged from 2 sources: (1) the Center for International Blood and Marrow Transplant Research, an observational transplantation registry, and (2) the Pediatric Health Information Services, an administrative database from freestanding children's hospitals. We captured exposure to 3 classes of antibiotics used for empiric treatment of febrile neutropenia: (1) broad-spectrum cephalosporins, (2) antipseudomonal penicillins, and (3) carbapenems. The primary outcome was grade II-IV aGVHD; secondary outcomes were grade III-IV aGVHD and lower GI GVHD. The adjusted logistic regression model (full cohort) and time-to-event analysis (subcohort) included transplantation characteristics, GVHD risk factors, and adjunctive antibiotic exposures as covariates. The full cohort included 2550 patients at 36 centers; the subcohort included 1174 patients. In adjusted models, carbapenems were associated with an increased risk of grade II-IV aGVHD in the full cohort (adjusted odds ratio [aOR], 1.24; 95% confidence interval [CI], 1.02 to 1.51) and subcohort (sub hazard ratio [HR], 1.31; 95% CI, 0.99 to 1.72), as well as with an increased risk of grade III-IV aGVHD (subHR, 1.77; 95% CI, 1.25 to 2.52). Early carbapenem exposure (before day 0) especially impacted aGVHD risk. For antipseudomonal penicillins, the associations with aGVHD were in the direction of increased risk but were not statistically significant. There was no identified association between broad-spectrum cephalosporins and aGVHD. Carbapenems, more than other broad-spectrum antibiotics, should be used judiciously in pediatric HCT recipients to minimize aGVHD risk. Further research is needed to clarify the mechanism underlying this association.

µJ-level multi-cycle terahertz generation in a periodically poled Rb:KTP crystal.

We demonstrate multi-cycle terahertz (MC-THz) generation in a 15.5 mm long periodically poled rubidium (Rb)-doped potassium titanyl phosphate (Rb:PPKTP) crystal with a poling period of 300 µm. By cryogenically cooling the crystal to 77 K, up to 0.72 µJ terahertz energy is obtained at a frequency of 0.5 THz with a 3 GHz bandwidth. A maximum internal optical-to-terahertz conversion efficiency of 0.16% is achieved, which is comparable with results achieved using periodically poled lithium niobate crystal. Neither photorefractive effects nor damage was observed with up to 900mJ/cm2, showing the great potential of Rb:PPKTP for multi-millijoule-level MC-THz generation.

Risk Factors for Graft-versus-Host Disease in Haploidentical Hematopoietic Cell Transplantation Using Post-Transplant Cyclophosphamide.

Post-transplant cyclophosphamide (PTCy) has significantly increased the successful use of haploidentical donors with a relatively low incidence of graft-versus-host disease (GVHD). Given its increasing use, we sought to determine risk factors for GVHD after haploidentical hematopoietic cell transplantation (haplo-HCT) using PTCy. Data from the Center for International Blood and Marrow Transplant Research on adult patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myeloid leukemia who underwent PTCy-based haplo-HCT (2013 to 2016) were analyzed and categorized into 4 groups based on myeloablative (MA) or reduced-intensity conditioning (RIC) and bone marrow (BM) or peripheral blood (PB) graft source. In total, 646 patients were identified (MA-BM = 79, MA-PB = 183, RIC-BM = 192, RIC-PB = 192). The incidence of grade 2 to 4 acute GVHD at 6 months was highest in MA-PB (44%), followed by RIC-PB (36%), MA-BM (36%), and RIC-BM (30%) (P = .002). The incidence of chronic GVHD at 1 year was 40%, 34%, 24%, and 20%, respectively (P < .001). In multivariable analysis, there was no impact of stem cell source or conditioning regimen on grade 2 to 4 acute GVHD; however, older donor age (30 to 49 versus <29 years) was significantly associated with higher rates of grade 2 to 4 acute GVHD (hazard ratio [HR], 1.53; 95% confidence interval [CI], 1.11 to 2.12; P = .01). In contrast, PB compared to BM as a stem cell source was a significant risk factor for the development of chronic GVHD (HR, 1.70; 95% CI, 1.11 to 2.62; P = .01) in the RIC setting. There were no differences in relapse or overall survival between groups. Donor age and graft source are risk factors for acute and chronic GVHD, respectively, after PTCy-based haplo-HCT. Our results indicate that in RIC haplo-HCT, the risk of chronic GVHD is higher with PB stem cells, without any difference in relapse or overall survival.

Composite GRFS and CRFS Outcomes After Adult Alternative Donor HCT.

PURPOSE: There is no consensus on the best choice of an alternative donor (umbilical cord blood [UCB], haploidentical, one-antigen mismatched [7/8]-bone marrow [BM], or 7/8-peripheral blood [PB]) for hematopoietic cell transplantation (HCT) for patients lacking an HLA-matched related or unrelated donor. METHODS: We report composite end points of graft-versus-host disease (GVHD)-free relapse-free survival (GRFS) and chronic GVHD (cGVHD)-free relapse-free survival (CRFS) in 2,198 patients who underwent UCB (n = 838), haploidentical (n = 159), 7/8-BM (n = 241), or 7/8-PB (n = 960) HCT. All groups were divided by myeloablative conditioning (MAC) intensity or reduced intensity conditioning (RIC), except haploidentical group in which most received RIC. To account for multiple testing, P < .0071 in multivariable analysis and P < .00025 in direct pairwise comparisons were considered statistically significant. RESULTS: In multivariable analysis, haploidentical group had the best GRFS, CRFS, and overall survival (OS). In the direct pairwise comparison of other groups, among those who received MAC, there was no difference in GRFS or CRFS among UCB, 7/8-BM, and 7/8-PB with serotherapy (alemtuzumab or antithymocyte globulin) groups. In contrast, the 7/8-PB without serotherapy group had significantly inferior GRFS, higher cGVHD, and a trend toward worse CRFS (hazard ratio [HR], 1.38; 95% CI, 1.13 to 1.69; P = .002) than the 7/8-BM group and higher cGVHD and trend toward inferior CRFS (HR, 1.36; 95% CI, 1.14 to 1.63; P = .0006) than the UCB group. Among patients with RIC, all groups had significantly inferior GRFS and CRFS compared with the haploidentical group. CONCLUSION: Recognizing the limitations of a registry retrospective analysis and the possibility of center selection bias in choosing donors, our data support the use of UCB, 7/8-BM, or 7/8-PB (with serotherapy) grafts for patients undergoing MAC HCT and haploidentical grafts for patients undergoing RIC HCT. The haploidentical group had the best GRFS, CRFS, and OS of all groups.

Inferior Outcomes with Cyclosporine and Mycophenolate Mofetil after Myeloablative Allogeneic Hematopoietic Cell Transplantation.

Combination therapy with a calcineurin inhibitor (CNI), such as cyclosporine (CSA) or tacrolimus (Tac), and methotrexate (MTX) or mycophenolate mofetil (MMF) is a widely used approach to graft-versus-host disease (GVHD) prevention. Data on the comparative effectiveness of MMF compared with MTX are limited and conflicting, however. We analyzed data from the Center for International Blood and Marrow Transplant Research for adult patients undergoing first myeloablative hematopoietic cell transplantation (HCT) from an HLA-identical matched related donor (MRD; n = 3979) or matched unrelated donor (URD; n = 4163) using CSA+MMF, CSA+MTX, Tac+MMF, or Tac+MTX for GVHD prevention between 2000 and 2013. Within the MRD cohort, 2252 patients received CSA+MTX, 1391 received Tac+MTX, 114 received CSA+MMF, and 222 received Tac+MMF. Recipients of CSA+MMF had a higher incidence of acute GVHD grade II-IV (hazard ratio [HR], 1.65; 95% confidence interval [CI], 1.24 to 2.20; P < .001) and grade III-IV (HR, 1.92; 95% CI, 1.31 to 2.83; P < .001) compared with Tac+MTX. The use of CSA+MMF was also associated with inferior overall survival (OS) (HR, 2.31; 95% CI, 1.73 to 3.09; P < .001) due to higher transplantation-related mortality (TRM) (HR, 4.03; 95% CI, 2.61 to 6.23; P < .001) compared with Tac+MTX. Within the URD cohort, 974 patients received CSA+MTX, 2697 received Tac+MTX, 68 received CSA+MMF, and 424 received Tac+MMF. CSA+MMF was again significantly associated with a higher incidence of grade III-IV acute GVHD (HR, 2.31; 95% CI, 1.57 to 3.42; P <0001), worse OS (HR, 2.36; 95% CI, 1.67 to 3.35; P < .001), and higher TRM (HR, 3.09; 95% CI, 2.00 to 4.77; P < .001), compared with Tac+MTX and other regimens. Thus, this large retrospective comparison of MMF versus MTX in combination with CSA or Tac demonstrates significantly worse GVHD and survival outcomes with CSA+MMF compared with Tac+MTX.

Impact of T Cell Dose on Outcome of T Cell-Replete HLA-Matched Allogeneic Peripheral Blood Stem Cell Transplantation.

Data on whether the T cell dose of allogeneic peripheral blood stem cell (PBSC) products influences transplantation outcomes are conflicting. Using the Center for International Blood and Marrow Transplant Research database, we identified 2736 adult patients who underwent first allogeneic PBSC transplantation for acute leukemia or myelodysplastic syndrome between 2008 and 2014 using an HLA-matched sibling donor (MSD) or an 8/8-matched unrelated donor (MUD). We excluded ex vivo and in vivo T cell-depleted transplantations. Correlative analysis was performed between CD3+ T cell dose and the risk of graft-versus-host-disease (GVHD), relapse, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS). Using maximum likelihood estimation, we identified CD3+ T cell dose cutoff that separated the risk of acute GVHD (aGVHD) grade II-IV in both the MSD and MUD groups. A CD3+ T cell dose cutoff of 14 × 107 cells/kg identified MSD/low CD3+ (n = 223) and MSD/high CD3+ (n = 1214), and a dose of 15 × 107 cells/kg identified MUD/low CD3+ (n = 197) and MUD/high CD3+ (n = 1102). On univariate analysis, the MSD/high CD3+ group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MSD/low CD3+ group (33% versus 25%; P = .009). There were no differences between the 2 groups in engraftment rate, risk of aGVHD grade III-IV or chronic GVHD (cGVHD), NRM, relapse, DFS, or OS. The MUD/high CD3+ group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MUD/low CD3+ group (49% versus 41%; P = .04). There were no differences between the 2 groups in engraftment rate, risk of severe aGVHD or cGVHD, NRM, relapse, DFS, or OS. Multivariate analysis of the MSD and MUD groups failed to show an association between CD3+ T cell dose and the risk of either aGVHD grade II-IV (P = .10 and .07, respectively) or cGVHD (P = .80 and .30, respectively). Subanalysis of CD4+ T cells, CD8+ T cells, and CD4+/CD8+ ratio failed to identify cutoff values predictive of transplantation outcomes; however, using the log-rank test, the sample size was suboptimal for identifying a difference at this cutoff cell dose. In this registry study, the CD3+ T cell dose of PBSC products did not influence the risk of aGVHD or cGVHD or other transplantation outcomes when using an MSD or an 8/8-matched MUD. Subset analyses of CD4+ and CD8+ T cell doses were not possible given our small sample size.

GRFS and CRFS in alternative donor hematopoietic cell transplantation for pediatric patients with acute leukemia.

We report graft-versus-host disease (GVHD)-free relapse-free survival (GRFS) (a composite end point of survival without grade III-IV acute GVHD [aGVHD], systemic therapy-requiring chronic GVHD [cGVHD], or relapse) and cGVHD-free relapse-free survival (CRFS) among pediatric patients with acute leukemia (n = 1613) who underwent transplantation with 1 antigen-mismatched (7/8) bone marrow (BM; n = 172) or umbilical cord blood (UCB; n = 1441). Multivariate analysis was performed using Cox proportional hazards models. To account for multiple testing, P < .01 for the donor/graft variable was considered statistically significant. Clinical characteristics were similar between UCB and 7/8 BM recipients, because most had acute lymphoblastic leukemia (62%), 64% received total body irradiation-based conditioning, and 60% received anti-thymocyte globulin or alemtuzumab. Methotrexate-based GVHD prophylaxis was more common with 7/8 BM (79%) than with UCB (15%), in which mycophenolate mofetil was commonly used. The univariate estimates of GRFS and CRFS were 22% (95% confidence interval [CI], 16-29) and 27% (95% CI, 20-34), respectively, with 7/8 BM and 33% (95% CI, 31-36) and 38% (95% CI, 35-40), respectively, with UCB (P < .001). In multivariate analysis, 7/8 BM vs UCB had similar GRFS (hazard ratio [HR], 1.12; 95% CI, 0.87-1.45; P = .39), CRFS (HR, 1.06; 95% CI, 0.82-1.38; P = .66), overall survival (HR, 1.07; 95% CI, 0.80-1.44; P = .66), and relapse (HR, 1.44; 95% CI, 1.03-2.02; P = .03). However, the 7/8 BM group had a significantly higher risk for grade III-IV aGVHD (HR, 1.70; 95% CI, 1.16-2.48; P = .006) compared with the UCB group. UCB and 7/8 BM groups had similar outcomes, as measured by GRFS and CRFS. However, given the higher risk for grade III-IV aGVHD, UCB might be preferred for patients lacking matched donors.

Imaging the Renner-Teller effect using laser-induced electron diffraction.

Structural information on electronically excited neutral molecules can be indirectly retrieved, largely through pump-probe and rotational spectroscopy measurements with the aid of calculations. Here, we demonstrate the direct structural retrieval of neutral carbonyl disulfide (CS2) in the [Formula: see text] excited electronic state using laser-induced electron diffraction (LIED). We unambiguously identify the ultrafast symmetric stretching and bending of the field-dressed neutral CS2 molecule with combined picometer and attosecond resolution using intrapulse pump-probe excitation and measurement. We invoke the Renner-Teller effect to populate the [Formula: see text] excited state in neutral CS2, leading to bending and stretching of the molecule. Our results demonstrate the sensitivity of LIED in retrieving the geometric structure of CS2, which is known to appear as a two-center scatterer.

Proinflammatory Cytokine and Adipokine Levels in Adult Unrelated Marrow Donors Are Not Associated with Hematopoietic Cell Transplantation Outcomes.

Graft-versus-host disease (GVHD) is a frequent cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (allo-HCT). GVHD occurs when donor lymphocytes are activated by inflammatory cytokines and alloantigens. The role of donor biologic characteristics, such as basal inflammation, has not been investigated as a risk factor for GVHD but is theoretically transferrable to the recipient. We evaluated donor serum and plasma concentrations of cytokines and adipokines (IL-1ß, IL-6, tumor necrosis factor [TNF]-α, leptin, suppression of tumorigenicity-2, and adiponectin) from test (n = 210) and replication (n = 250) cohorts of matched, unrelated transplant peripheral blood stem cell recipients identified through the Center for International Blood and Marrow Transplantation Research between 2000 and 2011 for hematologic malignancies. Hazard ratios were estimated for acute (grades II to IV and III to IV) and chronic GVHD, overall survival, disease-free survival, transplant-related mortality, and relapse for each cytokine or adipokine, adjusting for significant covariates. The lowest cytokine quartile was considered as the reference group for each model. To account for multiple testing P < .01 was considered the threshold for significance. In the test cohort a borderline significant association was identified between donor serum IL-1ß concentrations and grades III to IV acute GVHD in the recipient (P = .01), and a significant inverse association was identified between donor TNF-α concentrations and chronic GVHD (P = .006). These findings were not validated in the replication cohort. Although the initial associations between cytokine levels and allo-HCT outcomes were not validated, the idea that donor characteristics may be transferable to the recipient remains an exciting area for future research.

Comparative Analysis of Calcineurin Inhibitor-Based Methotrexate and Mycophenolate Mofetil-Containing Regimens for Prevention of Graft-versus-Host Disease after Reduced-Intensity Conditioning Allogeneic Transplantation.

The combination of a calcineurin inhibitor (CNI) such as tacrolimus (TAC) or cyclosporine (CYSP) with methotrexate (MTX) or with mycophenolate mofetil (MMF) has been commonly used for graft-versus-host disease (GVHD) prophylaxis after reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (alloHCT), but there are limited data comparing efficacy of the 2 regimens. We evaluated 1564 adult patients who underwent RIC alloHCT for acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS) from 2000 to 2013 using HLA-identical sibling (matched related donor [MRD]) or unrelated donor (URD) peripheral blood graft and received CYSP or TAC with MTX or MMF for GVHD prophylaxis. Primary outcomes of the study were acute and chronic GVHD and overall survival (OS). The study divided the patient population into 4 cohorts based on regimen: MMF-TAC, MMF-CYSP, MTX-TAC, and MTX-CYSP. In the URD group, MMF-CYSP was associated with increased risk of grade II to IV acute GVHD (relative risk [RR], 1.78; P < .001) and grade III to IV acute GVHD (RR, 1.93; P = .006) compared with MTX-TAC. In the URD group, use of MMF-TAC (versus MTX-TAC) lead to higher nonrelapse mortality. (hazard ratio, 1.48; P = .008). In either group, no there was no difference in chronic GVHD, disease-free survival, and OS among the GVHD prophylaxis regimens. For RIC alloHCT using MRD, there are no differences in outcomes based on GVHD prophylaxis. However, with URD RIC alloHCT, MMF-CYSP was inferior to MTX-based regimens for acute GVHD prevention, but all the regimens were equivalent in terms of chronic GVHD and OS. Prospective studies, targeting URD recipients are needed to confirm these results.

Peripheral Blood versus Bone Marrow from Unrelated Donors: Bone Marrow Allografts Have Improved Long-Term Overall and Graft-versus-Host Disease-Free, Relapse-Free Survival.

Peripheral blood (PB) and bone marrow (BM) from unrelated donors can serve as a graft source for hematopoietic cell transplantation (HCT). Currently, PB is most commonly used in roughly 80% of adult recipients. Determining the long-term impact of graft source on outcomes would inform this decision. Data collected by the Center for International Blood and Marrow Transplant Research from 5200 adult recipients of a first HCT from an 8/8 or 7/8 HLA antigen-matched unrelated donor for treatment of acute leukemia, chronic myelogenous leukemia, or myelodysplastic syndrome between 2001 and 2011 were analyzed to determine the impact of graft source on graft-versus-host disease (GVHD) relapse-free survival (GRFS), defined as freedom from grade III/IV acute GVHD, chronic GVHD requiring immunosuppressive therapy, relapse, and death, and overall survival. GRFS at 2 years was superior in BM recipients compared with PB recipients (16%; 95% confidence interval [CI], 14% to 18% versus 10%; 95% CI, 8% to 11%; P <.0001) in the 8/8 HLA-matched cohort and 7/8 HLA-matched cohort (11%; 95% CI, 8% to 14% versus 5%; 95% CI, 4% to 7%; P = .001). With 8/8 HLA-matched unrelated donors, overall survival at 5 years was superior in recipients of BM (43%; 95% CI, 40% to 46% versus 38%; 95% CI, 36% to 40%; P = .014). The inferior 5-year survival in the PB cohort was attributable to a higher frequency of deaths while in remission compared with the BM cohort. For recipients of 7/8 HLA-matched grafts, survival at 5 years was similar in BM recipients and PB recipients (32% versus 29%; P = .329). BM grafts are associated with improved long-term GRFS and overall survival in recipients of matched unrelated donor HCT and should be considered the unrelated allograft of choice, when available, for adults with acute leukemia, chronic myelogenous leukemia, and myelodysplastic syndrome.

Hematopoietic cell transplant for acute myeloid leukemia and myelodysplastic syndrome: conditioning regimen intensity.

In this study, we sought to identify specific individual high-intensity or reduced-intensity conditioning regimens with the best relapse-free survival (RFS) rather than the global high- vs reduced-intensity regimen comparison. Patients (median age, 58 years) with acute myeloid leukemia (AML; n = 1258), who were in first or subsequent remission, or with MDS (n = 951) who had refractory anemia with unilineage or multilineage dysplasia, 5q- syndrome, or refractory anemia with excess blasts received nonirradiation-containing regimens and were transplanted between 2009 and 2014 in the United States. Three-year RFS with high-intensity busulfan/cyclophosphamide (Bu4/Cy; 44%) was comparable to conditioning with high-intensity fludarabine/busulfan (Flu/Bu4; 44%), reduced-intensity fludarabine/melphalan (Flu/Mel; 52%; P = .53), and Flu/Mel + anti-thymocyte globulin (ATG; 44%; P = .38). RFS was lower with reduced-intensity Flu/Bu2 + ATG (31%; P = .0006). RFS was also lower with high-intensity Flu/Bu4 + ATG (38%; P = .05) and reduced-intensity Flu/Bu2 (38%; P = .02), although the difference did not reach the level of significance set for these analysis. RFS with Flu/Mel was superior to RFS with Flu/Bu2 (P = .01) and Flu/Bu2 + ATG (P = .0006). The 3-year incidence of relapse was 22% with Flu/Mel compared with 46% with Flu/Bu2 and 56% with Flu/Bu2 + ATG. With only a modest reduction in nonrelapse mortality with the Flu/Bu2 regimens, the higher relapse incidence resulted in lower RFS. The data support optimal RFS with Bu4/Cy, Flu/Bu4, and Flu/Mel regimens for AML in remission or MDS. The low relapse rate with reduced-intensity Flu/Mel resulted in RFS comparable to that after the higher-intensity regimens.

Upper gastrointestinal acute graft-versus-host disease adds minimal prognostic value in isolation or with other graft-versus-host disease symptoms as currently diagnosed and treated.

Upper gastrointestinal acute graft-versus-host disease is reported in approximately 30% of hematopoietic stem cell transplant recipients developing acute graft-versus-host disease. Currently classified as Grade II in consensus criteria, upper gastrointestinal acute graft-versus-host disease is often treated with systemic immunosuppression. We reviewed the Center for International Blood and Marrow Transplant Research database to assess the prognostic implications of upper gastrointestinal acute graft-versus-host disease in isolation or with other acute graft-versus-host disease manifestations. 8567 adult recipients of myeloablative allogeneic hematopoietic stem cell transplant receiving T-cell replete grafts for acute leukemia, chronic myeloid leukemia or myelodysplastic syndrome between 2000 and 2012 were analyzed. 51% of transplants were from unrelated donors. Reported upper gastrointestinal acute graft-versus-host disease incidence was 12.1%; 2.7% of recipients had isolated upper gastrointestinal acute graft-versus-host disease, of whom 95% received systemic steroids. Patients with isolated upper gastrointestinal involvement had similar survival, disease-free survival, transplant-related mortality, and relapse as patients with Grades 0, I, or II acute graft-versus-host disease. Unrelated donor recipients with isolated upper gastrointestinal acute graft-versus-host disease had less subsequent chronic graft-versus-host disease than those with Grades I or II disease (P=0.016 and P=0.0004, respectively). Upper gastrointestinal involvement added no significant prognostic information when present in addition to other manifestations of Grades I or II acute graft-versus-host disease. If upper gastrointestinal symptoms were reclassified as Grade 0 or I, 425 of 2083 patients (20.4%) with Grade II disease would be downgraded, potentially impacting the interpretation of clinical trial outcomes. Defining upper gastrointestinal acute graft-versus-host disease as a Grade II entity, as it is currently diagnosed and treated, is not strongly supported by this analysis. The general approach to diagnosis, treatment and grading of upper gastrointestinal symptoms and their impact on subsequent acute graft-versus-host disease therapy warrants reevaluation.

Segmented Terahertz Electron Accelerator and Manipulator (STEAM).

Acceleration and manipulation of electron bunches underlie most electron and X-ray devices used for ultrafast imaging and spectroscopy. New terahertz-driven concepts offer orders-of-magnitude improvements in field strengths, field gradients, laser synchronization and compactness relative to conventional radio-frequency devices, enabling shorter electron bunches and higher resolution with less infrastructure while maintaining high charge capacities (pC), repetition rates (kHz) and stability. We present a segmented terahertz electron accelerator and manipulator (STEAM) capable of performing multiple high-field operations on the 6D-phase-space of ultrashort electron bunches. With this single device, powered by few-micro-Joule, single-cycle, 0.3 THz pulses, we demonstrate record THz-acceleration of >30 keV, streaking with <10 fs resolution, focusing with >2 kT/m strength, compression to ~100 fs as well as real-time switching between these modes of operation. The STEAM device demonstrates the feasibility of THz-based electron accelerators, manipulators and diagnostic tools enabling science beyond current resolution frontiers with transformative impact.

Graft-versus-host disease in recipients of male unrelated donor compared with parous female sibling donor transplants.

Optimal donor selection is critical for successful allogeneic hematopoietic cell transplantation (HCT). Donor sex and parity are well-established risk factors for graft-versus-host disease (GVHD), with male donors typically associated with lower rates of GVHD. Well-matched unrelated donors (URDs) have also been associated with increased risks of GVHD as compared with matched sibling donors. These observations raise the question of whether male URDs would lead to more (or less) favorable transplant outcomes as compared with parous female sibling donors. We used the Center for International Blood and Marrow Transplant Research registry to complete a retrospective cohort study in adults with acute myeloid leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome, who underwent T-cell replete HCT from these 2 donor types (parous female sibling or male URD) between 2000 and 2012. Primary outcomes included grade 2 to 4 acute GVHD (aGVHD), chronic GVHD (cGVHD), and overall survival. Secondary outcomes included disease-free survival, transplant-related mortality, and relapse. In 2813 recipients, patients receiving male URD transplants (n = 1921) had 1.6 times higher risk of grade 2 to 4 aGVHD (P < .0001). For cGVHD, recipient sex was a significant factor, so donor/recipient pairs were evaluated. Female recipients of male URD grafts had a higher risk of cGVHD than those receiving parous female sibling grafts (relative risk [RR] = 1.43, P < .0001), whereas male recipients had similar rates of cGVHD regardless of donor type (RR = 1.09, P = .23). Donor type did not significantly affect any other end point. We conclude that when available, parous female siblings are preferred over male URDs.

87-W 1018-nm Yb-fiber ultrafast seeding source for cryogenic Yb: yttrium lithium fluoride amplifier.

We demonstrate a compact and robust Yb-fiber master-oscillator power-amplifier system operating at 1018 nm with 2.5-nm bandwidth and 1-ns stretched pulse duration. It produces 87-W average power and 4.9-µJ pulse energy, constituting a powerful seed source for cryogenically cooled ultrafast Yb: yttrium lithium fluoride (Yb:YLF) amplifiers.

Influence of Age on Acute and Chronic GVHD in Children Undergoing HLA-Identical Sibling Bone Marrow Transplantation for Acute Leukemia: Implications for Prophylaxis.

Relapse remains the major cause of mortality after hematopoietic cell transplantation (HCT) for pediatric acute leukemia. Previous research has suggested that reducing the intensity of calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis may be an effective strategy for abrogating the risk of relapse in pediatric patients undergoing matched sibling donor (MSD) HCT. We reasoned that the benefits of this strategy could be maximized by selectively applying it to those patients least likely to develop GVHD. We conducted a study of risk factors for GVHD, to risk-stratify patients based on age. Patients age <18 years with leukemia who received myeloablative, T cell-replete MSD bone marrow transplantation and calcineurin inhibitor-based GVHD prophylaxis between 2000 and 2013 and were entered into the Center for International Blood and Marrow Transplant Research registry were included. The cumulative incidence of grade II-IV acute GVHD (aGVHD) was 19%, that of grade II-IV aGVHD 7%, and that of chronic GVHD (cGVHD) was 16%. Compared with age 13 to 18 years, age 2 to 12 years was associated with a lower risk of grade II-IV aGVHD (hazard ratio [HR], .42; 95% confidence interval [CI], .26 to .70; P = .0008), grade II-IV aGVHD (HR, .24; 95% CI, .10 to .56; P = .001), and cGVHD (HR, .32; 95% CI, .19 to .54; P < .001). Compared with 2000-2004, the risk of grade II-IV aGVHD was lower in children undergoing transplantation in 2005-2008 (HR, .36; 95% CI, .20 to .65; P = .0007) and in 2009-2013 (HR, .24; 95% CI. .11 to .53; P = .0004). Similarly, the risk of grade III-IV aGVHD was lower in children undergoing transplantation in 2005-2008 (HR, .23; 95% CI, .08 to .65; P = .0056) and 2009-2013 (HR, .16; 95% CI, .04 to .67; P = .0126) compared with those doing so in 2000-2004. We conclude that aGVHD rates have decreased significantly over time, and that children age 2 to 12 years are at very low risk for aGVHD and cGVHD. These results should be validated in an independent analysis, because these patients with high-risk malignancies may be good candidates for trials of reduced GVHD prophylaxis.