| 1. |
- Park, Kwang-Hyun, et al.
(författare)
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RNA activation-independent DNA targeting of the Type III CRISPR-Cas system by a Csm complex
- 2017
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Ingår i: EMBO Reports. - : Wiley-VCH Verlagsgesellschaft. - 1469-221X .- 1469-3178. ; 18:5, s. 826-840
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Tidskriftsartikel (refereegranskat)abstract
- The CRISPR-Cas system is an adaptive and heritable immune response that destroys invading foreign nucleic acids. The effector complex of the Type III CRISPR-Cas system targets RNA and DNA in a transcription-coupled manner, but the exact mechanism of DNA targeting by this complex remains elusive. In this study, an effector Csm holocomplex derived from Thermococcus onnurineus is reconstituted with a minimalistic combination of Csm1(1)2(1)3(3)4(1)5(1), and shows RNA targeting and RNA-activated single-stranded DNA (ssDNA) targeting activities. Unexpectedly, in the absence of an RNA transcript, it cleaves ssDNA containing a sequence complementary to the bound crRNA guide region in a manner dependent on the HD domain of the Csm1 subunit. This nuclease activity is blocked by a repeat tag found in the host CRISPR loci. The specific cleavage of ssDNA without a target RNA suggests a novel ssDNA targeting mechanism of the Type III system, which could facilitate the efficient and complete degradation of foreign nucleic acids.
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| 2. |
- Park, Kwang-Hyun, et al.
(författare)
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Tetrameric architecture of an active phenol-bound form of the AAA(+) transcriptional regulator DmpR
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The Pseudomonas putida phenol-responsive regulator DmpR is a bacterial enhancer binding protein (bEBP) from the AAA+ ATPase family. Even though it was discovered more than two decades ago and has been widely used for aromatic hydrocarbon sensing, the activation mechanism of DmpR has remained elusive. Here, we show that phenol-bound DmpR forms a tetramer composed of two head-to-head dimers in a head-to-tail arrangement. The DmpR-phenol complex exhibits altered conformations within the C-termini of the sensory domains and shows an asymmetric orientation and angle in its coiled-coil linkers. The structural changes within the phenol binding sites and the downstream ATPase domains suggest that the effector binding signal is propagated through the coiled-coil helixes. The tetrameric DmpR-phenol complex interacts with the σ54 subunit of RNA polymerase in presence of an ATP analogue, indicating that DmpR-like bEBPs tetramers utilize a mechanistic mode distinct from that of hexameric AAA+ ATPases to activate σ54-dependent transcription.
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| 3. |
- Chhabra, Saurabh, et al.
(författare)
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Myeloablative vs reduced-intensity conditioning allogeneic hematopoietic cell transplantation for chronic myeloid leukemia
- 2018
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 2:21, s. 2922-2936
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Tidskriftsartikel (refereegranskat)abstract
- Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative treatment of chronic myeloid leukemia (CML). Optimal conditioning intensity for allo-HCT for CML in the era of tyrosine kinase inhibitors (TKIs) is unknown. Using the Center for International Blood and Marrow Transplant Research database, we sought to determine whether reduced-intensity/nonmyeloablative conditioning (RIC) allo-HCT and myeloablative conditioning (MAC) result in similar outcomes in CML patients. We evaluated 1395 CML allo-HCT recipients between the ages of 18 and 60 years. The disease status at transplant was divided into the following categories: chronic phase 1, chronic phase 2 or greater, and accelerated phase. Patients in blast phase at transplant and alternative donor transplants were excluded. The primary outcome was overall survival (OS) after allo-HCT. MAC (n = 1204) and RIC allo-HCT recipients (n = 191) from 2007 to 2014 were included. Patient, disease, and transplantation characteristics were similar, with a few exceptions. Multivariable analysis showed no significant difference in OS between MAC and RIC groups. In addition, leukemia-free survival and nonrelapse mortality did not differ significantly between the 2 groups. Compared with MAC, the RIC group had a higher risk of early relapse after allo-HCT (hazard ratio [HR], 1.85; P = .001). The cumulative incidence of chronic graft-versus-host disease (cGVHD) was lower with RIC than with MAC (HR, 0.77; P = .02). RIC provides similar survival and lower cGVHD compared with MAC and therefore may be a reasonable alternative to MAC for CML patients in the TKI era.
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| 4. |
- Cornell, Robert F., et al.
(författare)
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Allogeneic Transplantation for Relapsed Waldenström Macroglobulinemia and Lymphoplasmacytic Lymphoma
- 2017
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Ingår i: Biology of blood and marrow transplantation. - : Elsevier BV. - 1083-8791 .- 1523-6536. ; 23:1, s. 60-66
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Tidskriftsartikel (refereegranskat)abstract
- Waldenstrom macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) is characterized by lymphoplasmacytic proliferation, lymph node and spleen enlargement, bone marrow involvement, and IgM production. Treatment varies based on the extent and biology of disease. In some patients, the use of allogeneic hematopoietic cell transplantation (alloHCT) may have curative potential. We evaluated long-term outcomes of 144 patients who received adult alloHCT for WM/LPL. Data were obtained from the Center for International Blood and Marrow Transplant Research database (2001 to 2013). Patients received myeloablative (n = 67) or reduced-intensity conditioning (RIC; n = 67). Median age at alloHCT was 53 years, and median time from diagnosis to transplantation was 41 months. Thirteen percent (n = 18) failed prior autologous HCT. About half (n = 82, 57%) had chemosensitive disease at the time of transplantation, whereas 22% had progressive disease. Rates of progression-free survival, overall survival, relapse, and nonrelapse mortality at 5 years were 46%, 52%, 24%, and 30%, respectively. Patients with chemosensitive disease and better pretransplant disease status experienced significantly superior overall survival. There were no significant differences in progression-free survival based on conditioning (myeloablative, 50%, versus RIC, 41%) or graft source. Conditioning intensity did not impact treatment-related mortality or relapse. The most common causes of death were primary disease and graft-versus-host disease (GVHD). AlloHCT yielded durable survival in select patients with WM/LPL. Strategies to reduce mortality from GVHD and post-transplant relapse are necessary to improve this approach.
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| 5. |
- Dandoy, Christopher E., et al.
(författare)
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Incidence, Risk Factors, and Outcomes of Patients Who Develop Mucosal Barrier Injury-Laboratory Confirmed Bloodstream Infections in the First 100 Days After Allogeneic Hematopoietic Stem Cell Transplant
- 2020
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Ingår i: JAMA Network Open. - : AMER MEDICAL ASSOC. - 2574-3805. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Patients undergoing hematopoietic stem cell transplant (HSCT) are at risk for bloodstream infection (BSI) secondary to translocation of bacteria through the injured mucosa, termed mucosal barrier injury-laboratory confirmed bloodstream infection (MBI-LCBI), in addition to BSI secondary to indwelling catheters and infection at other sites (BSI-other).Objective: To determine the incidence, timing, risk factors, and outcomes of patients who develop MBI-LCBI in the first 100 days after HSCT.Design, Setting, and Participants: A case-cohort retrospective analysis was performed using data from the Center for International Blood and Marrow Transplant Research database on 16875 consecutive pediatric and adult patients receiving a first allogeneic HSCT from January 1, 2009, to December 31, 2016. Patients were classified into 4 categories: MBI-LCBI (1481 [8.8%]), MBI-LCBI and BSI-other (698 [4.1%]), BSI-other only (2928 [17.4%]), and controls with no BSI (11768 [69.7%]). Statistical analysis was performed from April 5 to July 17, 2018.Main Outcomes and Measures: Demographic characteristics and outcomes, including overall survival, chronic graft-vs-host disease, and transplant-related mortality (only for patients with malignant disease), were compared among groups.Results: Of the 16875 patients in the study (9737 [57.7%] male; median [range] age, 47 [0.04-82] years) 13686 (81.1%) underwent HSCT for a malignant neoplasm, and 3189 (18.9%) underwent HSCT for a nonmalignant condition. The cumulative incidence of MBI-LCBI was 13% (99% CI, 12%-13%) by day 100, and the cumulative incidence of BSI-other was 21% (99% CI, 21%-22%) by day 100. Median (range) time from transplant to first MBI-LCBI was 8 (<1 to 98) days vs 29 (<1 to 100) days for BSI-other. Multivariable analysis revealed an increased risk of MBI-LCBI with poor Karnofsky/Lansky performance status (hazard ratio [HR], 1.21 [99% CI, 1.04-1.41]), cord blood grafts (HR, 2.89 [99% CI, 1.97-4.24]), myeloablative conditioning (HR, 1.46 [99% CI, 1.19-1.78]), and posttransplant cyclophosphamide graft-vs-host disease prophylaxis (HR, 1.85 [99% CI, 1.38-2.48]). One-year mortality was significantly higher for patients with MBI-LCBI (HR, 1.81 [99% CI, 1.56-2.12]), BSI-other (HR, 1.81 [99% CI, 1.60-2.06]), and MBI-LCBI plus BSI-other (HR, 2.65 [99% CI, 2.17-3.24]) compared with controls. Infection was more commonly reported as a cause of death for patients with MBI-LCBI (139 of 740 [18.8%]), BSI (251 of 1537 [16.3%]), and MBI-LCBI plus BSI (94 of 435 [21.6%]) than for controls (566 of 4740 [11.9%]).Conclusions and Relevance: In this cohort study, MBI-LCBI, in addition to any BSIs, were associated with significant morbidity and mortality after HSCT. Further investigation into risk reduction should be a clinical and scientific priority in this patient population. This cohort study examines the incidence, timing, risk factors, and outcomes of patients who develop mucosal barrier injury-laboratory confirmed bloodstream infection (MBI-LCBI) in the first 100 days after hematopoietic stem cell transplant (HSCT).
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| 6. |
- Deol, Abhinav, et al.
(författare)
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Does FLT3 Mutation Impact Survival After Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia? : A Center for International Blood and Marrow Transplant Research (CIBMTR) Analysis
- 2016
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Ingår i: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 122:19, s. 3005-3014
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with FMS like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML) have a poor prognosis and are referred for early allogeneic hematopoietic stem cell transplantation (HCT). METHODS: Data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were used to evaluate 511 adult patients with de novo AML who underwent HCT during 2008 through 2011 to determine whether FLT3 mutations had an impact on HCT outcomes. RESULTS: In total, 158 patients (31%) had FLT3 mutations. Univariate and multivariate analyses revealed an increased risk of relapse at 3 years in the FLT3 mutated group compared with the wild-type (WT) group (38% [95% confidence interval (CI), 30%-45%] vs 28% [95% CI, 24%-33%]; P = .04; relative risk, 1.60 [95% CI, 1.15-2.22]; P = .0048). However, FLT3 mutation status was not significantly associated with nonrelapse mortality, leukemia-free survival, or overall survival. Although more patients in the FLT3 mutated group died from relapsed primary disease compared with those in the WT group (60% vs 46%), the 3-year overall survival rate was comparable for the 2 groups (mutated group: 49%; 95% CI, 40%-57%; WT group: 55%, 95% CI, 50%-60%; P = .20). CONCLUSIONS: The current data indicate that FLT3 mutation status did not adversely impact overall survival after HCT, and about 50% of patients with this mutation who underwent HCT were long-term survivors.
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| 7. |
- Eapen, Mary, et al.
(författare)
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Long-Term Survival and Late Deaths after Hematopoietic Cell Transplantation for Primary Immunodeficiency Diseases and Inborn Errors of Metabolism.
- 2012
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Ingår i: Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation. - 1523-6536. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- It is uncertain whether late mortality rates after hematopoietic cell transplantation for severe combined immunodeficiency (SCID), non-SCID primary immunodeficiency diseases (non-SCID PIDD), and inborn errors of metabolism (IEM) return to rates observed in the general population, matched for age, sex, and nationality. We studied patients with SCID (n = 201), non-SCID PIDD (n = 405), and IEM (n = 348) who survived for at least 2 years after transplantation with normal T cell function (SCID) or >95% donor chimerism (non-SCID PIDD and IEM). Importantly, mortality rate was significantly higher in these patients compared with the general population for several years after transplantation. The rate decreased toward the normal rate in patients with SCID and non-SCID PIDD beyond 6 years after transplantation, but not in patients with IEM. Active chronic graft-versus-host disease at 2 years was associated with increased risk of late mortality for all diseases (hazard ratio [HR], 1.87; P = .05). In addition, late mortality was higher in patients with non-SCID PIDD who received T cell-depleted grafts (HR 4.16; P = .007) and in patients with IEM who received unrelated donor grafts (HR, 2.72; P = .03) or mismatched related donor grafts (HR, 3.76; P = .01). The finding of higher mortality rates in these long-term survivors for many years after transplantation confirms the need for long-term surveillance.
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| 8. |
- Gerds, Aaron T., et al.
(författare)
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Outcomes after Umbilical Cord Blood Transplantation for Myelodysplastic Syndromes
- 2017
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Ingår i: Biology of blood and marrow transplantation. - : Elsevier. - 1083-8791 .- 1523-6536. ; 23:6, s. 971-979
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Tidskriftsartikel (refereegranskat)abstract
- For patients with hematologic malignancies undergoing allogeneic hematopoietic cell transplantation, umbilical cord blood transplantation (UCBT) has become an acceptable alternative donor source in the absence of a matched sibling or unrelated donor. To date, however, there have been few published series dedicated solely to describing the outcomes of adult patients with myelodysplastic syndrome (MDS) who have undergone UCBT. Between 2004 and 2013, 176 adults with MDS underwent UCBT as reported to the Center for International Blood and Marrow Transplant Research. Median age at the time of transplantation was 56 years (range, 18-73 years). The study group included 10% with very low, 23% with low, 19% with intermediate, 19% with high, and 13% with very high-risk Revised International Prognostic Scoring System (IPSS-R) scores. The 100-day probability of grade II-IV acute graft-versus-host disease (GVHD) was 38%, and the 3-year probability of chronic GVHD was 28%. The probabilities of relapse and transplantation-related mortality (TRM) at 3 years were 32% and 40%, respectively, leading to a 3-year disease-free survival (DFS) of 28% and an overall survival (OS) of 31%. In multivariate analysis, increasing IPSS-R score at the time of HCT was associated with inferior TRM (P = .0056), DFS (P = .018), and OS (P = .0082), but not with GVHD or relapse. The presence of pretransplantation comorbidities was associated with TRM (P = .001), DFS (P = .02), and OS (P = .001). Reduced intensity conditioning was associated with increased risk of relapse (relative risk, 3.95; 95% confidence interval, 1.78-8.75; P < .001), and although a higher proportion of myeloablative UCBTs were performed in patients with high-risk disease, the effect of conditioning regimen intensity was the same regardless of IPSS-R score. For some individuals who lack a matched sibling or unrelated donor, UCBT can result in long-term DFS; however, the success of UCBT in this population is hampered by a high rate of TRM. (C) 2017 American Society for Blood and Marrow Transplantation.
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| 9. |
- Gowin, Krisstina, et al.
(författare)
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Survival following allogeneic transplant in patients with myelofibrosis
- 2020
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Ingår i: Blood Advances. - : AMER SOC HEMATOLOGY. - 2473-9529 .- 2473-9537. ; 4:9, s. 1965-1973
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Tidskriftsartikel (refereegranskat)abstract
- Allogeneic hematopoietic cell transplantation (HCT) is the only curative therapy for myelofibrosis (MF). In this large multicenter retrospective study, overall survival (OS) in MF patients treated with allogeneic HCT (551 patients) and without HCT (non-HCT) (1377 patients) was analyzed with Cox proportional hazards model. Survival analysis stratified by the Dynamic International Prognostic Scoring System (DIPSS) revealed that the first year of treatment arm assignment, due to upfront risk of transplant-related mortality (TRM), HCT was associated with inferior OS compared with non-HCT (non-HCT vs HCT: DIPSS intermediate 1 [Int-1]: hazard ratio [HR] = 0.26, P < .0001; DIPSS-Int-2 and higher: HR, 0.39, P < .0001). Similarly, in the DIPSS low-risk MF group, due to upfront TRM risk, OS was superior with non-HCT therapies compared with HCT in the first-year post treatment arm assignment (HR, 0.16, P = .006). However, after 1 year, OS was not significantly different (HR, 1.38, P = .451). Beyond 1 year of treatment arm assignment, an OS advantage with HCT therapy in Int-1 and higher DIPSS score patients was observed (non-HCT vs HCT: DIPSS-Int-1: HR, 2.64, P < .0001; DIPSS-Int-2 and higher: HR, 2.55, P < .0001). In conclusion, long-term OS advantage with HCT was observed for patients with Int-1 or higher risk MF, but at the cost of early TRM. The magnitude of OS benefit with HCT increased as DIPSS risk score increased and became apparent with longer follow-up.
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| 10. |
- Hill, Brian T., et al.
(författare)
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Assessment of Impact of HLA Type on Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for Chronic Lymphocytic Leukemia
- 2018
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Ingår i: Biology of blood and marrow transplantation. - : Elsevier BV. - 1083-8791 .- 1523-6536. ; 24:3, s. 581-586
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Tidskriftsartikel (refereegranskat)abstract
- Chronic lymphocytic leukemia (CLL) is a common hematologic malignancy with many highly effective therapies. Chemorefractory disease, often characterized by deletion of chromosome 17p, has historically been associated with very poor outcomes, leading to the application of allogeneic hematopoietic stem cell transplantation (allo-HCT) for medically fit patients. Although the use of allo-HCT has declined since the introduction of novel targeted therapy for the treatment of CLL, there remains significant interest in understanding factors that may influence the efficacy of allo-HCT, the only known curative treatment for CLL. The potential benefit of transplantation is most likely due to the presence of alloreactive donor T cells that mediate the graft-versus-leukemia (GVL) effect. The recognition of potentially tumor-specific antigens in the context of class I and II major histocompatibility complex on malignant B lymphocytes by donor T cells may be influenced by subtle differences in the highly polymorphic HLA locus. Given previous reports of specific HLA alleles impacting the incidence of CLL and the clinical outcomes of allo-HCT for CLL, we sought to study the overall survival and progression-free survival of a large cohort of patients with CLL who underwent allo-HCT from fully HLA-matched related and unrelated donors at Center for International Blood and Marrow Transplant Research transplantation centers. We found no statistically significant association of allo-HCT outcomes in CLL based on previously reported HLA combinations. Additional study is needed to further define the immunologic features that portend a more favorable GVL effect after allo-HCT for CLL.
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