A 7-Day Decitabine-Included Conditioning Regimen Accelerated Donor Hematopoietic Engraftment while Reduced the Occurrence of Mucositis without Interfering with Prognosis.

INTRODUCTION: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the standard and curative treatment strategy for patients with hematologic malignancies. Recently, decitabine-included regimens have been investigated by several studies including ours, which may prevent relapse of primary malignant diseases. METHODS: This study was to retrospectively evaluate a 7-day decitabine-included regimen with reduced dose of idarubicin for patients with hematologic malignancies who underwent allo-HSCT. RESULTS: A total of 84 patients were enrolled, including 24 cases in 7-day and 60 cases in 5-day decitabine groups, respectively. Patients conditioned with 7-day decitabine regimen showed accelerated neutrophil (12.05 ± 1.97 vs. 13.86 ± 3.15; u = 9.309, p < 0.001) and platelet (16.32 ± 6.27 vs. 21.37 ± 8.57; u = 8.887, p < 0.001) engraftment compared with those treated with 5-day decitabine regimen. Patients in the 7-day decitabine group showed a significantly lower incidence rate of total (50.00% [12/24] versus 78.33% [47/60]; χ2 = 6.583, p = 0.010) and grade III or above (4.17% [1/24] vs. 31.67% [19/60]; χ2 = 7.147, p = 0.008) oral mucositis compared to those in the 5-day decitabine group. However, the occurrence of other major complications post-allo-HSCT and outcomes of patients in these two groups were comparable. CONCLUSION: These results demonstrate that this 7-day decitabine-contained new conditioning regimen seems to be feasible and safe for patients with myeloid neoplasms who receive allo-HSCT, and a large-scale prospective study is needed to confirm the findings of this study.

Conditioning Regimen of 5-Day Decitabine Administration for Allogeneic Stem Cell Transplantation in Patients with Myelodysplastic Syndrome and Myeloproliferative Neoplasms.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for patients with myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). However, post-HSCT relapse remains a major cause of treatment failure. Here we assessed the efficacy of a new conditioning regimen comprising decitabine (Dec), busulfan (Bu), cyclophosphamide (Cy), fludarabine (Flu), and cytarabine (Ara-c) for allo-HSCT in patients with MDS and MDS/MPN. A total of 48 patients were enrolled, including 44 with MDS and 4 with chronic myelomonocytic leukemia (CMML). Patients received Dec 20 mg/m2/day on days -9 to -5, combined with a Bu/Cy/Flu/Ara-c-modified preparative regimen. At a median follow-up of 522 days (range, 15 to 1313 days), the overall survival (OS) was 86%, relapse incidence was 12%, and nonrelapse mortality was 12%. The incidence of severe acute (grade III-IV) graft-versus-host disease (GVHD) was 23% and that of chronic GVHD was 15%. At 2 years, OS was 74% and 86%, respectively for high-risk and very-high-risk patients with MDS. Survival was promising in patients with poor-risk gene mutations, such as TP53 and ASXL1 (88%), and in those with ≥3 gene mutations (79%). Results of immunomonitoring studies revealed that proper natural killer cells made essential contributions to these favorable clinical outcomes. Overall, this new regimen was associated with a low relapse rate, low incidence and severity of GVHD, and satisfactory survival in allo-HSCT recipients with MDS and MDS/MPN.

Targeting acute myeloid leukemia with a proapoptotic peptide conjugated to a Toll-like receptor 2-mediated cell-penetrating peptide.

Cell-penetrating peptides provide a unique platform to create a new generation of cancer therapeutics with enhanced efficacy and diminished toxicity. In our study, enhanced expression of toll-like receptor 2 (TLR2) was observed in acute myeloid leukemia (AML) cells. Screening of a phage display peptide library using Biopanning and Rapid Analysis of Selective Interactive Ligands (BRASIL) identified a TLR2-binding peptide motif, Pep2. We show that the TLR2-binding peptide motif targeted and penetrated into leukemia cells in a TLR2-dependent manner. Moreover, a synthetic, chimeric peptide composed of the TLR2-binding motif linked to a programmed cell death-inducing sequence, D(KLAKLAK)2, induced apoptosis in AML cells with high TLR2 expression (TLR2(high)) but not in chronic myeloid leukemia (CML) cells with low TLR2 expression (TLR2(low)). The antileukemia activity of this chimeric peptide was confirmed in leukemia patient samples and an animal model of myeloid leukemia, as the development of leukemia was significantly delayed in mice with TLR2(high) AML compared to TLR2(low) CML NOD/SCID mice. TUNEL assays on bone marrow tissue slices revealed that the chimerical peptide induced leukemia cell apoptosis in a TLR2-dependent manner. Together, our findings indicate that TLR2 is a potential therapeutic target for the prevention and treatment of AML, and the prototype, Pep2-D(KLAKLAK)2, is a promising drug candidate in this setting.

Plausible presence of new state in neutron stars with masses above 0.98MTOV.

We investigate the neutron star (NS) equation of state (EOS) by incorporating multi-messenger data of GW170817, PSR J0030 + 0451, PSR J0740 + 6620, and state-of-the-art theoretical progresses, including the information from chiral effective field theory (χEFT) and perturbative quantum chromodynamics (pQCD) calculation. Taking advantage of the various structures sampling by a single-layer feed-forward neural network model embedded in the Bayesian nonparametric inference, the structure of NS matter's sound speed cs is explored in a model-agnostic way. It is found that a peak structure is common in the cs2 posterior, locating at (2.4-4.8)ρsat (nuclear saturation density) and cs2 exceeds c2/3 at 90% credibility. The non-monotonic behavior suggests evidence of the state deviating from the hadronic matter inside the very massive NSs. Assuming the new/exotic state is featured as it is softer than typical hadronic models or even with hyperons, we find that a sizable (⩾10-3M⊙) exotic core, likely made of quark matter, is plausible for the NS with a gravitational mass above about 0.98MTOV, where MTOV represents the maximum gravitational mass of a non-rotating cold NS. The inferred MTOV=(2.18-0.13+0.27)M⊙ (90% credibility) is well consistent with the value of (2.17-0.12+0.15)M⊙ estimated independently with GW170817/GRB 170817A/AT2017gfo assuming a temporary supramassive NS remnant formed after the merger. PSR J0740 + 6620, the most massive NS detected so far, may host a sizable exotic core with a probability of ≈0.36.

Machine learning-aided scoring of synthesis difficulties for designer chromosomes.

Designer chromosomes are artificially synthesized chromosomes. Nowadays, these chromosomes have numerous applications ranging from medical research to the development of biofuels. However, some chromosome fragments can interfere with the chemical synthesis of designer chromosomes and eventually limit the widespread use of this technology. To address this issue, this study aimed to develop an interpretable machine learning framework to predict and quantify the synthesis difficulties of designer chromosomes in advance. Through the use of this framework, six key sequence features leading to synthesis difficulties were identified, and an eXtreme Gradient Boosting model was established to integrate these features. The predictive model achieved high-quality performance with an AUC of 0.895 in cross-validation and an AUC of 0.885 on an independent test set. Based on these results, the synthesis difficulty index (S-index) was proposed as a means of scoring and interpreting synthesis difficulties of chromosomes from prokaryotes to eukaryotes. The findings of this study emphasize the significant variability in synthesis difficulties between chromosomes and demonstrate the potential of the proposed model to predict and mitigate these difficulties through the optimization of the synthesis process and genome rewriting.

Safety and efficacy of a modified busulfan/cyclophosphamide conditioning regimen incorporating cladribine for autologous hematopoietic stem cell transplantation in acute myeloid leukemia.

This is a small phase I study examining the safety and efficacy of a cladribine (CLAD)-containing conditioning regimen prior to autologous hematopoietic stem cell transplantion (auto-HSCT) for patients with acute myeloid leukemia (AML). All patients, aged 15-54 years (median 32 years), had favorable/intermediate risk AML (n = 20) or acute promyelocytic leukemia (APL; n = 2) and no evidence of minimal residual disease (MRD) prior to transplantation. Fourteen of the 22 patients received the conditioning regimen as follows: busulfan (Bu) + cyclophosphamide (Cy) + CLAD + cytarabine (Ara-c) or idarubicin. The conditioning regimen of 8 patients was without Cy nor idarubicin to reducing adverse cardiac reaction: the regimen of Bu + CLAD+ Ara-c for 6 patients; and the regimen of Bu + melphalan + CLAD + Ara-c for the other 2 patients. All 22 AML patients received peripheral blood stem cell transplantation. The number of infused mononuclear cells and CD34+ cells was 10.00 (2.88-20.97) × 108/kg and 1.89 (1.52-10.44) × 106/kg, respectively. Hematopoietic reconstitution was achieved in all patients, with a median time of 13 (10-34) days for neutrophils and 28 (14-113) days for platelets. Two patients suffered from pulmonary infection, 4 patients suffered from septicemia during the neutropenic stage, and the others suffered from infection or gastrointestinal reaction without exceeding grade 3 after conditioning, which were all alleviated by anti-infection and other supportive treatment. None of the patients died of transplantation-related complications. At a median follow-up of 29.5 (ranging from 4.0 to 60.0) months, three patients relapsed after auto-HSCT at a median time of 6 (ranging from 0.5 to 10.0) months. One patient died due to relapse at 18 months after auto-HSCT. The remaining 21 patients were all alive, including 19 patients with negative MRD. The other 2 patients achieved negative MRD after allogeneic HSCT or chemotherapy. The estimated 2-year survival, relapse, and Leukemia-free survival rates were 94.1 ± 5.7%, 14.7 ± 7.9% and 85.3 ± 7.9%, respectively. A CLAD-combination conditioning regimen is efficient and safe for auto-HSCT, indicating an effective approach for AML treatment.

Robust data storage in DNA by de Bruijn graph-based de novo strand assembly.

DNA data storage is a rapidly developing technology with great potential due to its high density, long-term durability, and low maintenance cost. The major technical challenges include various errors, such as strand breaks, rearrangements, and indels that frequently arise during DNA synthesis, amplification, sequencing, and preservation. In this study, a de novo strand assembly algorithm (DBGPS) is developed using de Bruijn graph and greedy path search to meet these challenges. DBGPS shows substantial advantages in handling DNA breaks, rearrangements, and indels. The robustness of DBGPS is demonstrated by accelerated aging, multiple independent data retrievals, deep error-prone PCR, and large-scale simulations. Remarkably, 6.8 MB of data is accurately recovered from a severely corrupted sample that has been treated at 70 °C for 70 days. With DBGPS, we are able to achieve a logical density of 1.30 bits/cycle and a physical density of 295 PB/g.

Regulatory T Cells in GVHD Therapy.

Graft versus host disease (GVHD) is a common complication and the leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Pharmacological immunosuppression used in GVHD prophylaxis and treatment lacks specificity and can increase the likelihood of infection and relapse. Regulatory T lymphocytes (Tregs) play a vital role in restraining excessive immune responses and inducing peripheral immune tolerance. In particular, clinical trials have demonstrated that Tregs can prevent and treat GVHD, without increasing the risk of relapse and infection. Hence, adoptive transfer of Tregs to control GVHD using their immunosuppressive properties represents a promising therapeutic approach. To optimally apply Tregs for control of GVHD, a thorough understanding of their biology is necessary. In this review, we describe the biological characteristics of Tregs, including how the stability of FOXP3 expression can be maintained. We will also discuss the mechanisms underlying Tregs-mediated modulation of GVHD and approaches to effectively increase Tregs' numbers. Finally, we will examine the developing trends in the use of Tregs for clinical therapy.

Hematopoietic stem cell transplantation activity in China 2019: a report from the Chinese Blood and Marrow Transplantation Registry Group.

Between 2008 and 2019, 58,914 hematopoietic stem cell transplantations (HSCTs) were reported to the Chinese Blood and Marrow Transplantation Registry Group (CBMTRG) throughout China. In this report, we focus on 2019 data and describe current trends in HSCT in China. There was continued growth in transplant activity in China, with a rapid increase in haploidentical HSCT. In 2019, a total of 12,323 cases of HSCT were reported from 149 transplant teams, 78% (9597 cases) were allogeneic HSCTs. Haploidentical donor (HID) HSCT accounted for 60% (5771 cases) of allogeneic HSCT. The most common indications for allogeneic HSCT for malignant disease were acute myeloid leukemia (AML) (37%) and acute lymphoblastic leukemia (ALL) (24%), and the largest proportion of non-malignant diseases comprised aplastic anemia (AA) (13%). Multiple stem cell source composed 70% of HID and 28% of MSD, which was typical in China. The BuCy based regimen (59%) was the most popular conditioning regimen for allogeneic HSCT, followed by the BuFlu based regimen (23%) and TBI-based regimen (12%). This survey clearly shows comprehensive information about the current state and recent trends for HSCT in China. Further efforts should be made to obtain detailed information.

The consensus from The Chinese Society of Hematology on indications, conditioning regimens and donor selection for allogeneic hematopoietic stem cell transplantation: 2021 update.

The consensus recommendations in 2018 from The Chinese Society of Hematology (CSH) on indications, conditioning regimens and donor selection for allogeneic hematopoietic stem cell transplantation (allo-HSCT) facilitated the standardization of clinical practices of allo-HSCT in China and progressive integration with the world. There have been new developments since the initial publication. To integrate recent developments and further improve the consensus, a panel of experts from the CSH recently updated the consensus recommendations, which are summarized as follows: (1) there is a new algorithm for selecting appropriate donors for allo-HSCT candidates. Haploidentical donors (HIDs) are the preferred donor choice over matched sibling donors (MSDs) for patients with high-risk leukemia or elderly patients with young offspring donors in experienced centers. This replaces the previous algorithm for donor selection, which favored MSDs over HIDs. (2) Patients with refractory/relapsed lymphoblastic malignancies are now encouraged to undergo salvage treatment with novel immunotherapies prior to HSCT. (3) The consensus has been updated to reflect additional evidence for the application of allo-HSCT in specific groups of patients with hematological malignancies (intermediate-risk acute myeloid leukemia (AML), favorable-risk AML with positive minimal residual disease, and standard-risk acute lymphoblastic leukemia). (4) The consensus has been updated to reflect additional evidence for the application of HSCT in patients with nonmalignant diseases, such as severe aplastic anemia and inherited diseases. (5) The consensus has been updated to reflect additional evidence for the administration of anti-thymocyte globulin, granulocyte colony-stimulating factors and post-transplantation cyclophosphamide in HID-HSCT.

Donor-derived CD19 CAR-T cell therapy of relapse of CD19-positive B-ALL post allotransplant.

Safety and efficacy of allogeneic anti-CD19 chimeric antigen receptor T cells (CAR-T cells) in persons with CD19-positive B-cell acute lymphoblastic leukemia (B-ALL) relapsing after an allotransplant remain unclear. Forty-three subjects with B-ALL relapsing post allotransplant received CAR-T cells were analyzed. 34 (79%; 95% confidence interval [CI]: 66, 92%) achieved complete histological remission (CR). Cytokine release syndrome (CRS) occurred in 38 (88%; 78, 98%) and was ≥grade-3 in 7. Two subjects died from multiorgan failure and CRS. Nine subjects (21%; 8, 34%) developed ≤grade-2 immune effector cell-associated neurotoxicity syndrome (ICANS). Two subjects developed ≤grade-2 acute graft-versus-host disease (GvHD). 1-year event-free survival (EFS) and survival was 43% (25, 62%). In 32 subjects with a complete histological remission without a second transplant, 1-year cumulative incidence of relapse was 41% (25, 62%) and 1-year EFS and survival, 59% (37, 81%). Therapy of B-ALL subjects relapsing post transplant with donor-derived CAR-T cells is safe and effective but associated with a high rate of CRS. Outcomes seem comparable to those achieved with alternative therapies but data from a randomized trial are lacking.

[A prospective multicenter study of rituximab combined with high-dose chemotherapy and autologous peripheral blood stem cell transplantation for aggressive B-cell lymphoma].

OBJECTIVE: To investigate the feasibility and efficacy of rituximab combined with high-dose chemotherapy supported by autologous peripheral blood stem cell transplantation (ASCT) in patients with aggressive B-cell non-Hodgkin lymphoma (NHL). METHODS: Twenty-eight patients with aggressive B-cell NHL (22 newly diagnosed, 6 relapsed) were enrolled in this study. The high-dose chemotherapy included CHOP regimen (CTX + ADM + VCR + PDN) for the newly diagnosed patients and DICE (DEX + IFO + DDP + VP-16) or EPOCH (VP-16 + PDN + VCR + CTX + ADM) for the relapsed patients. Each patient received infusion of rituximab at a dose of 375 mg/m(2) for four times, on D1 before and on D7 of peripheral blood stem cell mobilization, and on D1 before and D8 after stem cell reinfusion. RESULTS: Complete remission was achieved in all patients after high dose chemotherapy and ASCT. At a median follow-up of 37 months, the estimated overall 4-year survival and progression-free survival rate for all patients were 75.0% and 70.3%, respectively, while both were 72.7% for the previously untreated patients. The therapy was generally well tolerated with few side-effects attributable to rituximab. CONCLUSION: These results suggest that adding rituximab to high-dose chemotherapy with peripheral blood stem cell transplantation is feasible and may be beneficial for patients with aggressive B-cell non-Hodgkin lymphoma.

[Effects of killer immunoglobulin-like receptor and human leukocyte antigen class I ligand on the prognosis of related donor hematopoietic stem cell transplantation].

OBJECTIVE: To study the genotype distribution and the effects of killer immunoglobulin-like receptors (KIR) and human leukocyte antigen (HLA) class I ligand on related donor hematopoietic stem cell transplantation (HSCT). METHODS: The genotypes of donor/recipient HLA-Cw and donor KIR were determined by polymerase chain reaction-sequence specific primer (PCR-SSP) in 87 cases of related donor HSCT (40 cases were haploidentical HSCT, and the remaining 47 cases were HLA-identical sibling HSCT). RESULTS: All the donors possessed KIR2DL1, 2DL2/L3, 2DL4, 3DL2, and 3DL3, and 96.6% of donors possessed 3DL1. The rate of activating KIRs varied. 97.7% of the recipients expressed C1, while the rates of C2, Bw4, and HLA-A3/A11 were different. In haploidentical HSCT, KIR-HLA-mismatched group included 34 cases and the matched group included 6 cases. HLA-HLA-mismatched group included 31 cases and the matched group included 9 cases. In matched sibling donor HSCT, KIR-HLA-mismatched group included 42 cases and the matched group included 5 cases. KIR-HLA-mismatched group had higher 2-year disease-free survival (DFS) rate compared with KIR-HLA-matched group [ (71.5 +/- 6.5 ) % vs. (50.0 +/- 10.7)%, P < 0.05]. CONCLUSIONS: The rate of activating KIR is lower than inhibitory KIRs. Inhibitory KIR2DL1, 3DL1, and 3DL2 may play key roles in the natural killer cell alloreactivity. The DFS rate is higher in KIR-HLA-mismatched group than in KIR-HLA-matched group in related donor HSCT.

[Emerging role of Mitochondria in Maintenance of Hematopoietic Stem Cells--Review].

Mitochondria are double-membrane organelles existing only in eukaryotic cells. Mitochondria perform various important functions，such as producing energy，regulating signal transduction，and contributing to stress response. Recent studies have highlighted an important role of mitochondria in the determination of hematopoietic stem cells （HSC） fate. Limited biogenesis or timely clearance of mitochondria is an important way against oxidative stress，which favors the quiescence of HSC. Accumulation of mitochondria may lead to proliferation of HSC，even the aging of HSC. Mitochondrial signaling regulates Ca2+ concentration，which is essential for HSC differentiation. This review summarizes the current findings of the mitochondrial roles in HSC quiescence，self-renewal，lineage differentiation and aging.

[Relationship between Early Peak Temperature and Neutropenia Duration in Acute Leukemia Patients after Chemotherapy and Its Mechanism].

OBJECTIVE: To investigate the relationship between early peak body temperature and neutropenia duration and its potential mechanism. METHODS: A total of 111 patients with CR1 phase acute leukemia (AL) with neutropenia infection were enrolled in this study. The relationship between early peak body temperature and neutropenia duration was analyzed retrospectively, and the IL-6 serum level in patients with different peak of body temperature was detected, and the single cell culture system in vitro was established, the incorparation rate of EdU in vivo was detected, and the effect of IL-6 on mouse hematopoietic stem cells /progenitor cells was analyzed. RESULTS: Out of 111 patients with nentropenia, the body temperature <38 °C and the neutropenia duration 9.5±3.69 d were observed in 44 patients, while the body temperature >38 °C and neutropenia duration 7.33±4.20 d were observed in 69 patients, the differences between 2 groups was statistically signficant (P<0.05). The EdU test showed that the number of EdU+ hematopoietic stem cells and progenitor cells increased. The IL-6 level was different in patients with different peaks of initial bady temperature (P<0.05). The results of amimal experiment showed that the IL-6 could promote the proliferation of hematopoietic stem cells/ progenitor cells in vitro and in vivo. CONCLUSION: For patients with neutropenic infection when initial body temperature peak is <38 °C, the probability of neutropenia duration prolonging after chamotherapy increases, which may relate with promotive effect of pro-inflammatory cytokins on prliferation of hematopoietic stem cells/progenitor cells.

BCR-ABL enhances the prolyl isomerase activity of Pin 1 by interacting with DAPK1 in ph+ ALL.

Philadelphia chromosome (Ph)/BCR-ABL-positive (ph+ ) ALL is the most common genetic abnormality associated with ALL and has been shown to confer the worst prognosis to both children and adults. Increasing evidence has revealed that the dysregulation of prolyl isomerase Pin 1 contributes to multicancer development and progression, including ALL, although the underlying molecular mechanisms remain unclear. Here, we report that the expression of Pin 1 was enhanced in ph+ ALL patient samples and was associated positively with the expression of BCR-ABL. Genetically or pharmacologically inhibiting Pin 1 expression or activity produces potent therapeutic efficacy against ph+ ALL. We further demonstrated that BCR-ABL enhances the prolyl isomerase activity of Pin 1 by decreasing the phosphorylated level of Pin 1 at Ser 71 and interacting with DAPK1. The inhibition of BCR-ABL activity by imatinib in human ph+ ALL cells reduces the prolyl isomerase activity of Pin 1, further suggesting a key role of the newly identified BCR-ABL-Pin 1 axis in ph+ ALL progression. Thus, the combined suppression of Pin 1 and BCR-ABL proteins may be exploited as an additional target therapy for ph+ ALL.

[Clinical study on fluoroquinolone prophylaxis in neutropenia patients with acute leukemia].

OBJECTIVE: To investigate the clinical benefits and the impacts on distribution and antibiotic resistance of pathogenic bacterium associated with fluoroquinolone prophylaxis during neutropenia in patients with acute leukemia. METHODS: A total of 309 infection episodes occurred in patients with acute leukemia were retrospectively analyzed. The patients admitted in ward A (group A, n = 149) received oral ofloxacin as antibacterial prophylaxis during the neutropenia phase; no antibacterial prophylaxis was administered to the patients in ward B (group B, n = 160). The influences of prophylactic ofloxacin were determined by comparative evaluation on the clinical characteristics and the microbiological profile in both groups' patients. RESULTS: Almost all enrolled patients experienced severe neutropenia. The median durations of ANC (absolute neutrophil count, ANC) < 0.2 x 10(9)/L were 11 (range 0 - 43) days. The median persistence time of fever was 8(range 1 - 46) days. Prophylaxis of ofloxacin decreased the proportion of normal flora (P = 0.00). The frequency of Escherichia coli was higher in group A than group B (23.9%, 12.5%, respectively, P = 0.00). Exposure to ofloxacin didn't affect the distributions of other pathogenic bacteria. No difference in the rate of ESBL (+) Escherichia coli was discovered between ofloxacin and no ofloxacin prophylaxis groups (31.9%, 35.4%, respectively, P = 0.61). Commonly used antibiotics had similar activity against the major strains isolated from two groups. Patients who received antibacterial prophylaxis showed a lower incidence (10.7%) of upper respiratory infections/tonsillitis and a relative higher incidence (14.4%) of gastrointestinal tract infections than those without intervention measure. The prophylactic use of ofloxacin couldn't cut down the risk of septicemia. Ofloxacin prophylaxis did not display negative effect on initial clinical response (65.8% in group A, 60.6% in group B, respectively, P = 0.35) and final efficacy (96.0% in group A, 91.9% in group A, P = 0.14) to the same empirical antimicrobial treatment schemes. CONCLUSION: The fluoroquinolone prophylaxis induces diminishing proportion of normal flora and increasing frequency of Escherichia coli in severely neutropenic patients with acute leukemia, may not influence the distribution of other bacteria. The susceptibility of main pathogens may not be affected by antibiotic prophylaxis. The fluoroquinolone don't decrease the incidence of septicemia and infection in gastrointestinal tract. Our data suggest that more prudent use of antibiotic prophylaxis may be reasonable even in patients at high-risk for developing infection.

Impact of Human Leukocyte Antigen Loci and Haplotypes on Intestinal Acute Graft-versus-host Disease after Human Leukocyte Antigen-matched Sibling Peripheral Blood Stem Cell Transplantation.

BACKGROUND: Acute graft-versus-host disease (aGVHD) is a common and severe complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Some studies have found that the presence of certain specific human leukocyte antigen (HLA) loci could affect the occurrence of aGVHD. Meanwhile, the impact of HLA haplotypes on aGVHD has been rarely studied. This study aimed to investigate the effects of HLA loci and haplotypes on intestinal aGVHD. METHODS: Totally, 345 consecutive patients undergoing first HLA-matched sibling peripheral blood stem cell transplantation (PBSCT) from February 2004 to June 2013 at Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, were enrolled in this study. HLA loci and haplotypes of recipients with frequency over 5% were searched and their effects on intestinal aGVHD were investigated. Other important factors including donor age, recipient age, donor-recipient sex combinations, and conditioning regimens were also evaluated using logistic regression. Pure upper gastrointestinal tract aGVHD without diarrhea was excluded because the histological proof was unavailable. The follow-up end-point was 6 months after HSCT. RESULTS: The cumulative incidence of intestinal aGVHD was 19.4%, with 18.0% of the patients classified as classic aGVHD and 1.4% as persistent, recurrent, or late aGVHD. Multivariate analysis showed that HLA-A31 locus (odds ratio [OR] 2.893, 95% confidence interval [CI] [1.054, 7.935], P = 0.039), HLA B40-DR15 (OR 3.133, 95% CI [1.250, 7.857], P = 0.015), and HLA B46-DR9 haplotypes (OR 2.580, 95% CI [1.070, 6.220], P = 0.035), female donor for male recipient (OR 2.434, 95% CI [1.319, 4.493], P = 0.004) were risk factors for intestinal aGVHD. CONCLUSION: The presence of certain HLA loci and haplotypes may influence the occurrence of intestinal aGVHD in PBSCT with HLA-identical sibling donors.

TRIB3 Promotes APL Progression through Stabilization of the Oncoprotein PML-RARα and Inhibition of p53-Mediated Senescence.

Acute promyelocytic leukemia (APL) is driven by the oncoprotein PML-RARα, which antagonizes myeloid differentiation and promotes APL-initiating cell self-renewal. Combined all-trans retinoic acid (ATRA) with arsenic trioxide (As2O3) or chemotherapy dramatically improves the prognosis of APL patients. Here we report that expression of pseudokinase Tribble 3 (TRIB3) associates positively with APL progression and therapeutic resistance. The elevated TRIB3 expression promotes APL by interacting with PML-RARα and suppressing its sumoylation, ubiquitylation, and degradation. This represses PML nuclear body assembly, p53-mediated senescence, and cell differentiation, and supports cellular self-renewal. Genetically inhibiting TRIB3 expression or combination of a peptide disturbing TRIB3/PML-RARα interaction with ATRA/As2O3 eradicates APL by accelerating PML-RARα degradation. Our study provides insight into APL pathogenesis and a potential therapeutic option against APL.