Polarization-Insensitive Lithium Niobate-on-Insulator Interferometer.

The key components of a polarization-independent electro-optic (EO) interferometer, including the beam splitter, mode converter, and directional coupler, are designed based on a lithium niobate (LN) platform on an integrated insulator to ensure high extinction ratios. By elaborately designing the geometric structure of the multimode interference (MMI) coupler, beam splitting of equal proportions and directional coupling of higher-order modes are realized. The most prominent characteristic of the proposed interferometer is polarization insensitivity, which is realized by converting TM polarization into TE polarization using a mode converter, providing conditions for the study of light with different polarizations. At 1550 nm, the visibility of the interferometer is 97.59% and 98.16% for TE and TM, respectively, demonstrating the high performance of the proposed LN polarization-independent interferometer.

Spatial source, simulating improvement, and short-term health effect of high PM2.5 exposure during mutation event in the key urban agglomeration regions in China.

Air quality in China has significantly improved owing to the effective implementation of pollution control measures. However, mutation events caused by short-term spikes in PM2.5 in urban agglomeration regions continue to occur frequently. Identifying the spatial sources and influencing factors, as well as improving the prediction accuracy of high PM2.5 during mutation events, are crucial for public health. In this study, we firstly introduced discrete wavelet transform (DWT) to identify the mutation events with high PM2.5 concentration in the four key urban agglomerations, and evaluated the spatial sources for the polluted scenario using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Additionally, DWT was combined with a widely used artificial neural network (ANN) to improve the prediction accuracy of PM2.5 concentration seven days in advance (seven-day forecast). Results indicated that mutation events commonly occurred in the northern regions during winter time, which were under the control of both short-range transportation of dirty airmass as well as negative meteorology conditions. Compared with the ANN model alone, the average band errors decreased by 9% when using DWT-ANN model. The average correlation coefficient (R) and root mean square error (RMSE) obtained using the DWT-ANN improved by 10% and 12% compared to those obtained using the ANN, indicating the efficiency and accuracy of simulating PM2.5, by combining the DWT and ANN. The short-term mortality during mutation events was then calculated, with the total averted all-cause, cardiovascular, and respiratory deaths in the four regions, being 4751, 2554, and 582 persons, respectively. A declining trend in prevented deaths from 2018 to 2020 demonstrated that the pollution intensity during mutation events gradually decreased owing to the implementation of the Three-Year Action Plan to Win the Blue Sky Defense War. The method proposed in this study can be used by policymakers to take preventive measures in response to a sudden increase in PM2.5, thereby ensuring public health.

Increasing 1,4-Diaminobutane Production in Escherichia coli by Optimization of Cofactor PLP and NADPH Synthesis.

1,4-diaminobutane is widely used in the industrial production of polymers, pharmaceuticals, agrochemicals and surfactants. Owing to economic and environmental concerns, there has been a growing interest in using microbes to produce 1,4-diaminobutane. However, there is lack of research on the influence of cofactors pyridoxal phosphate (PLP) and NADPH on the synthesis of 1,4-diaminobutane. PLP serves as a cofactor of ornithine decarboxylase in the synthesis of 1,4-diaminobutane. Additionally, the synthesis of 1 mol 1,4-diaminobutane requires 2 mol NADPH, thus necessitating consideration of NADPH balance in the efficient synthesis of 1,4-diaminobutane by Escherichia coli. The aim of this study was to enhance the synthesis efficiency of 1,4-diaminobutane through increasing production of PLP and NADPH. By optimizing the expression of the genes associated with synthesis of PLP and NADPH in E. coli, cellular PLP and NADPH levels increased, and the yield of 1,4-diaminobutane also increased accordingly. Ultimately, using glucose as the primary carbon source, the yield of 1,4-diaminobutane in the recombinant strain NAP19 reached 272 mg/L·DCW, by increased 79% compared with its chassis strain.

Deep Attention Fusion Hashing (DAFH) Model for Medical Image Retrieval.

In medical image retrieval, accurately retrieving relevant images significantly impacts clinical decision making and diagnostics. Traditional image-retrieval systems primarily rely on single-dimensional image data, while current deep-hashing methods are capable of learning complex feature representations. However, retrieval accuracy and efficiency are hindered by diverse modalities and limited sample sizes. OBJECTIVE: To address this, we propose a novel deep learning-based hashing model, the Deep Attention Fusion Hashing (DAFH) model, which integrates advanced attention mechanisms with medical imaging data. METHODS: The DAFH model enhances retrieval performance by integrating multi-modality medical imaging data and employing attention mechanisms to optimize the feature extraction process. Utilizing multimodal medical image data from the Cancer Imaging Archive (TCIA), this study constructed and trained a deep hashing network that achieves high-precision classification of various cancer types. RESULTS: At hash code lengths of 16, 32, and 48 bits, the model respectively attained Mean Average Precision (MAP@10) values of 0.711, 0.754, and 0.762, highlighting the potential and advantage of the DAFH model in medical image retrieval. CONCLUSIONS: The DAFH model demonstrates significant improvements in the efficiency and accuracy of medical image retrieval, proving to be a valuable tool in clinical settings.

Astragaloside IV inhibits idiopathic pulmonary fibrosis through activation of autophagy by miR-21-mediated PTEN/PI3K/AKT/mTOR pathway.

As the main active ingredient of Astragalus, Astragaloside IV (AS-IV) can ameliorate pulmonary fibrosis. In this experiment, we studied how AS-IV reduces idiopathic pulmonary fibrosis (IPF). Bleomycin (BLM) or TGF-ß1 was treated in mice or alveolar epithelial cells to mimic IPF in vivo as well as in vitro. ASV-IV alleviated levels of inflammatory cytokines and fibrosis markers in IPF model. Through detection of autophagy-related genes, ASV-IV was observed to induce autophagy in IPF. Besides, ASV-IV inhibited miR-21 expression in IPF models, and overexpression of miR-21 could reverse the protective potential of ASV-IV on IPF. PTEN was targeted by miR-21 and was up-regulated by ASV-IV in IPF models. In addition, levels of inflammatory cytokines and fibrosis markers, autophagy, as well as the PI3K/AKT/mTOR pathway regulated by ASV-IV could be neutralized after treatment with autophagy inhibitors, miR-21 mimics, or si-PTEN. Our study demonstrates that ASV-IV inhibits IPF through activation of autophagy by miR-21-mediated PTEN/PI3K/AKT/mTOR pathway, suggesting that ASV-IV could be acted to be a promising therapeutic method for IPF.

Application of CMV-IVIg as prophylaxis against cytomegalovirus reactivation in allogeneic hematopoietic stem cell transplantation patients.

Cytomegalovirus (CMV) reactivation remains one of the major and life-threatening complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Yet, there is still a lack of safe and effective ways to prevent CMV reactivation in allo-HSCT patients. Here, we retrospectively analyzed a cohort of patients who underwent HSCT at our transplant center between 2018 and 2022 to evaluate the efficacy of prophylactic CMV-specific intravenous immunoglobulin (CMV-IVIg) against CMV reactivation. After Propensity Score Matching, the CMV reactivation rate was significantly decreased in the CMV-IVIg group (HR, 2.952; 95% CI,1.492-5.841; P = .002) compared with the control group. Additionally, the time duration of CMV reactivation (P = .001) and bacterial infection rate (P = .013) were significantly lower in the CMV-IVIg group. Moreover, prophylactic CMV-IVIg was more effective in CMV seropositive patients who received ATG as part of GVHD prevention (HR, 8.225; 95% CI,1.809-37.39; P = .006). In conclusion, CMV-IVIg is considered an effective and safe way to prevent CMV reactivation in HSCT recipients, which may be related to the acceleration of immune reconstitution in the early stage after transplantation.

Symptom networks in older adults with cancer: A network analysis.

INTRODUCTION: Due to aging, older adults with cancer (OAC) may be confronted with a complex interplay of multiple age-related issues; coupled with receiving cancer treatment, OAC may experience multiple concurrent symptoms that require the identification of the core symptom for effective management. Constructing symptom networks will help in the identification of core symptoms and help achieve personalized and precise interventions. Currently, few studies have used symptom networks to identify core symptoms in OAC. Our objectives were to construct symptom networks of OAC, explore the core symptoms, and compare the differences in symptom networks among various subgroups. MATERIALS AND METHODS: Secondary analysis was performed using data from 485 OAC collected in 2021 from a cross-sectional survey named the Shanghai CANcer Survivor (SCANS) Report. The MD Anderson Symptom Inventory (MDASI) was used to assess the incidence and severity of cancer-related symptoms. We used the R package to construct symptom networks and identify the centrality indices. The network comparison test was used to compare network differences among the subgroups. RESULTS: The most common and severe symptoms reported were fatigue, disturbed sleep, and difficulty remembering. The network density was 0.718. Vomiting (rs = 1.81, rb = 2.13), fatigue (rs = 1.54, rb = 1.93), and sadness (rs = 0.81, rb = 0.69) showed the highest strength values, which suggested that these symptoms were more likely to co-occur with other symptoms. The network comparison tests showed significant differences in symptom network density between the subgroups categorized as survival "< 5 years" and survival "≥ 5 years" (p = 0.002), as well as between the those with comorbidities and those without comorbidities (p = 0.037). DISCUSSION: Our study identified symptom networks in 485 OAC. Vomiting, fatigue, and sadness were important symptoms in the symptom networks of OAC. The symptom networks differed among populations with different survival durations and comorbidities. Our network analysis provides a reference for future targeted symptom management and interventions in OAC. In the future, conducting dynamic research on symptom networks will be crucial to explore interaction mechanisms and change trends between symptoms.

Influence of pollution control measures on the reduction of black carbon in an urban site of megacity, Tianjin, China based on ground-monitored and MERRA-2 reanalysis data.

The concentration of particulate matter (PM) has been reduced significantly with the implementation of air pollution control plans in Tianjin. However, as an important component of PM that can lead to global warming and adverse health effects, the influence of pollution control measures (PCM) on black carbon (BC) has been less studied. In this study, ten years of BC concentration satellite-based reanalysis data were collected from MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2), and their reliability was verified using ground-monitored BC data. Using the proposed Kolmogorov-Zurbenko and artificial neural network (KZ-ANN) model, the influences of meteorology and emission measures were separated. The results indicated that the overall meteorological conditions were not conducive to BC diffusion, especially in autumn and winter with low temperature, surface solar radiation, boundary layer height, and high atmospheric pressure, all of which increased the BC concentration. This study also found that although a significant reduction in BC emissions was observed in Tianjin (the total emissions of BC in 2020 dropped by 52 % compared with the level in 2013), the change in emission-influenced BC was relatively low (the concentration of emission-influenced BC in 2022 dropped by only 2.39 % compared to that in 2013). The reduction of emission-influenced BC concentration during the air pollution prevention control and action plan (APPC) was higher than the level during of the three-year action plan for winning the blue sky defense war (abbreviated as the Blue Sky Defense War). In addition, the lockdown measures during the Corona Virus Disease 2019 (COVID-19) did not have beneficial effect on the reduction of emission-influenced BC concentration. This phenomenon can be explained by the long-range transport of BC from surrounding areas, which was also proven by the results of the backward trajectory analysis. Therefore, efforts on emissions reduction in Tianjin were diminished. It is necessary to cooperate with the governments in surrounding areas to implement joint BC control measures, especially in autumn and winter.

OBIA: An Open Biomedical Imaging Archive.

With the development of artificial intelligence (AI) technologies, biomedical imaging data play an important role in scientific research and clinical application, but the available resources are limited. Here we present Open Biomedical Imaging Archive (OBIA), a repository for archiving biomedical imaging and related clinical data. OBIA adopts five data objects (Collection, Individual, Study, Series, and Image) for data organization, and accepts the submission of biomedical images of multiple modalities, organs, and diseases. In order to protect personal privacy, OBIA has formulated a unified de-identification and quality control process. In addition, OBIA provides friendly and intuitive web interfaces for data submission, browsing, and retrieval, as well as image retrieval. As of September 2023, OBIA has housed data for a total of 937 individuals, 4136 studies, 24,701 series, and 1,938,309 images covering 9 modalities and 30 anatomical sites. Collectively, OBIA provides a reliable platform for biomedical imaging data management and offers free open access to all publicly available data to support research activities throughout the world. OBIA can be accessed at https://ngdc.cncb.ac.cn/obia.

CCLHunter: An efficient toolkit for cancer cell line authentication.

Cancer cell lines are essential in cancer research, yet accurate authentication of these cell lines can be challenging, particularly for consanguineous cell lines with close genetic similarities. We introduce a new Cancer Cell Line Hunter (CCLHunter) method to tackle this challenge. This approach utilizes the information of single nucleotide polymorphisms, expression profiles, and kindred topology to authenticate 1389 human cancer cell lines accurately. CCLHunter can precisely and efficiently authenticate cell lines from consanguineous lineages and those derived from other tissues of the same individual. Our evaluation results indicate that CCLHunter has a complete accuracy rate of 93.27%, with an accuracy of 89.28% even for consanguineous cell lines, outperforming existing methods. Additionally, we provide convenient access to CCLHunter through standalone software and a web server at https://ngdc.cncb.ac.cn/cclhunter.

Detection of fluid motion direction based on the rotational Doppler effect of grafted perfect vortex beam.

Vortex beams have attracted much attention due to their unique rotational Doppler effect. With the in-depth study of vortex beams, many new vortex beams have been proposed gradually, while the detection of fluid motion is of great significance for the study of ocean turbulence. Based on the rotational Doppler effect of the grafted perfect vortex beam, we propose a non-embedded optical method for real-time detection of the magnitude and direction of fluid velocity and establish a two-dimensional fluid model for simulation verification. It is proved that the grafted perfect vortex beam can detect the magnitude and direction of the fluid velocity at the same time, which may provide a new way and theoretical support for the detection of fluid motion direction.

Reshifting Na+ from Shoots into Long Roots Is Associated with Salt Tolerance in Two Contrasting Inbred Maize (Zea mays L.) Lines.

Maize, as a glycophyte, is hypersensitive to salinity, but the salt response mechanism of maize remains unclear. In this study, the physiological, biochemical, and molecular responses of two contrasting inbred lines, the salt-tolerant QXH0121 and salt-sensitive QXN233 lines, were investigated in response to salt stress. Under salt stress, the tolerant QXH0121 line exhibited good performance, while in the sensitive QXN233 line, there were negative effects on the growth of the leaves and roots. The most important finding was that QXH0121 could reshift Na+ from shoots into long roots, migrate excess Na+ in shoots to alleviate salt damage to shoots, and also improve K+ retention in shoots, which were closely associated with the enhanced expression levels of ZmHAK1 and ZmNHX1 in QXH0121 compared to those in QXN233 under salt stress. Additionally, QXH0121 leaves accumulated more proline, soluble protein, and sugar contents and had higher SOD activity levels than those observed in QXN233, which correlated with the upregulation of ZmP5CR, ZmBADH, ZmTPS1, and ZmSOD4 in QXH0121 leaves. These were the main causes of the higher salt tolerance of QXH0121 in contrast to QXN233. These results broaden our knowledge about the underlying mechanism of salt tolerance in different maize varieties, providing novel insights into breeding maize with a high level of salt resistance.

Validation and calibration of aerosol optical depth and classification of aerosol types based on multi-source data over China.

A refined classification of aerosol types is essential to identify and control air pollution sources. This study focused on improving the resolution and accuracy of aerosol optical depth (AOD) and further refining the classification of aerosol types in China. We validated the accuracy of the AOD acquired using the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA2) and Copernicus Atmosphere Monitoring Service (CAMS) by comparing it with that acquired using from the Aeronet Robotic Network (AERONET). We simulated the AOD with high spatial resolution and accuracy based on the extremely randomized trees (ERT), adaptive boosting (AdaBoost), and gradient boosting decision trees (GBDT) models and identified aerosol types based on the Angstrom Exponent (AE) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the calibrated AOD. The results showed that CAMS overestimates AOD (21.4 %) and MERRA2 underestimates AOD (-17.3 %). Among the three machine learning models, the ERT model performed best, with a determination coefficient (R2) of 0.825 and the root-mean-square error (RMSE) of 0.174. Biomass burning/urban-industrial aerosols dominated China, with the largest contributions to southern, eastern, and central China in spring and summer. Clean continental aerosols contributed the most to southwestern China in fall and winter, whereas desert dust aerosols contributed the most to northwestern and eastern China in spring.

Somatic ARAF mutations in pediatric Langerhans cell histiocytosis: clinicopathologic, genetic and functional profiling.

ARAF mutations have been identified in a limited subset of patients with Langerhans cell histiocytosis (LCH), a rare disorder characterized by abnormal proliferation of Langerhans cells. LCH is primarily instigated by mutations in the mitogen-activated protein kinase (MAPK) signaling pathway, with BRAFV600E and MAP2K1 mutations constituting most cases. ARAF mutations in LCH highlight the heterogeneity of the disease and provide insights into its underlying molecular mechanisms. However, the occurrence of ARAF-positive LCH cases is extremely rare, with only two reported globally. Although they may be linked to a more aggressive form of LCH and a more severe clinical progression, the clinical significance and functional consequences of these mutations remain uncertain. We performed next-generation sequencing (NGS) to explore driver mutations in 148 pediatric LCH patients and recognized a series of mutations, including an identical novel somatic ARAF mutation, c.1046_1051delAGGCTT (p.Q349_F351delinsL), in four pediatric LCH patients. It was considered an ARAF hotspot mutation. All reported ARAF-positive patients worldwide exhibited characteristic pathological features of LCH, albeit with involvement across multiple systems. In vitro functional studies showed that this mutation could trigger the MAPKinase pathway and phosphorylate its downstream effectors MEK1/2 and ERK1/2 (relatively weaker than BRAFV600E). Over-activation of mutant A-Raf kinase could be inhibited by the BRAF inhibitor vemurafenib. LCH is uncommon, and ARAF mutation is even rarer. In our study, we have identified a novel hotspot somatic ARAF mutation, which has been verified through functional analysis to be an activating mutation. LCH patients with ARAF mutation typically have an unfavorable prognosis due to limited treatment experiences, although they do not exhibit a high relapse rate. To aid in the development of personalized treatment approaches and prognostic markers for LCH patients, it is recommended to conduct typical pathological and immunohistochemical examinations, as well as genetic tests utilizing a targeted gene panel or whole exome sequencing (WES), for LCH diagnosis, thereby promoting the use of inhibitor treatment strategies.

Anti-phospholipase A2 receptor-associated membranous nephropathy with human immunodeficiency virus infection treated with telitacicept: A case report.

BACKGROUND: The co-occurrence of Anti-phospholipase A2 receptor-associated membranous nephropathy (anti-PLA2R-MN) and human immunodeficiency virus (HIV) infection is a rare clinical scenario, presenting significant challenges in terms of management and treatment. CASE SUMMARY: A 32-year-old Chinese male diagnosed with HIV infection presented with a clinical history of proteinuria persisting for over two years. A kidney biopsy demonstrated subepithelial immune complex deposition and a thickened glomerular basement membrane, indicative of stage I-II membranous nephropathy. Immunofluorescence staining revealed granular deposition of PLA2R (3+) along the glomerular capillary loops, corroborated by a strongly positive anti-PLA2R antibody test (1:320). Initial treatment involving losartan potassium, rivaroxaban, tacrolimus, and rituximab was discontinued due to either poor effectiveness or the occurrence of adverse events. Following a regimen of weekly subcutaneous injections of telitacicept (160 mg), a marked decline in the 24 h urine protein was observed within a three-month period, accompanied by a rise in serum albumin level. No significant reductions in peripheral blood CD3+CD4+T and CD3+CD8+T cell counts were detected. The patient's physical and psychological conditions showed significant improvements, with no adverse events reported during the treatment course. CONCLUSION: Telitacicept might offer a potential therapeutic avenue for patients diagnosed with anti-PLA2R-MN concomitant with HIV infection.

Differentiating environmental scenarios to establish geochemical baseline values for heavy metals in soil: A case study of Hainan Island, China.

Soil heavy metal distributions exhibit regional heterogeneity due to the complex characteristics of parent materials and soil formation processes, emphasizing the need for appropriate regional standards prior to assessing soil risks. This study focuses on Hainan Island and employs the Multi-purpose Regional Geochemical Survey dataset to establish heavy metal geochemical baseline and background values for soil using an iterative method. Geographical detector analysis reveals that parent materials are the primary factor influencing heavy metal distribution, followed by soil types and land use. Heavy metal geochemical baseline values are established for the island's three environments and administrative regions. Notably, a universal geochemical baseline value cannot adequately represent regional variations in heavy metal distribution, with parent materials playing a crucial role in various scenarios. Locally applicable values based on parent material are the most representative for Hainan Island. This study provides a reference framework for developing region-specific environmental baseline values for soil heavy metal assessments.

Polymorphs of a 1:1 salt of sulfadiazine and piperazine-relative stability, dissolution studies, pharmacokinetics and anti-meningitis efficiency.

Two new salt forms of sulfadiazine (SDZ) and piperazine (PIP) were synthesized and characterized. Out of the two polymorphs (SDZ-PIP Ⅰ and SDZ-PIP II), SDZ-PIP Ⅱ is the more stable form at low temperature, room temperature and high temperature. The solution-mediated phase transformation result shows that SDZ-PIP II can transform into pure SDZ within 15 s in phosphate buffer at 37 °C, which leads to a loss in solubility advantage. The addition of 2 mg/mL PVP K30, a polymeric crystallization inhibitor, maintains the solubility advantage and permits supersaturation for a longer period of time. SDZ-PIP II showed 2.5 times the solubility of SDZ alone. The area under the curve (AUC) of SDZ-PIP II with 2 mg/mL PVP K30 was approximately 165% of that of SDZ alone. Moreover, SDZ-PIP II with PVP K30 was more effective than SDZ alone in treating meningitis. Therefore, the SDZ-PIP II salt improves the solubility, bioavailability, and anti-meningitis activity of SDZ.

Multi-aperture imaging with Fermat spiral sub-aperture arrangement.

Multi-aperture optical telescopes have been extensively studied owing to their high resolution, low cost, and light weight. The next generation of optical telescopes is predicted to be equipped with dozens or even hundreds of segmented lenses; therefore, it is necessary to optimize the arrangement of the lens array. This paper proposes a new structure called the Fermat spiral array (FSA) to replace the conventional hexagonal or ring array for the sub-aperture arrangement of a multi-aperture imaging system. The point spread function (PSF) and modulation transfer function (MTF) of the imaging system are compared in detail at single and multiple incident wavelengths. The FSA can effectively weaken the sidelobe intensity of the PSF, which is 12.8 dB lower on average than conventional ones with a single incident wavelength in the simulation and 4.45 dB lower in the experiment. A new MTF evaluation function is proposed to describe the mean level of MTF at mid-frequencies. The FSA can improve the MTF of the imaging system and weaken the ringing effect in the images. The imaging simulation indicates that FSA has superior imaging quality compared to conventional arrays, with a higher peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). The imaging experiments also achieve a higher SSIM with the FSA, which agrees well with the simulation results. The proposed FSA multi-aperture will help improve the imaging performance of next-generation optical telescopes.

MACdb: A Curated Knowledgebase for Metabolic Associations across Human Cancers.

Cancer is one of the leading causes of human death. As metabolomics techniques become more and more widely used in cancer research, metabolites are increasingly recognized as crucial factors in both cancer diagnosis and treatment. In this study, we developed MACdb (https://ngdc.cncb.ac.cn/macdb), a curated knowledgebase to recruit the metabolic associations between metabolites and cancers. Unlike conventional data-driven resources, MACdb integrates cancer-metabolic knowledge from extensive publications, providing high quality metabolite associations and tools to support multiple research purposes. In the current implementation, MACdb has integrated 40,710 cancer-metabolite associations, covering 267 traits from 17 categories of cancers with high incidence or mortality, based entirely on manual curation from 1,127 studies reported in 462 publications (screened from 5,153 research papers). MACdb offers intuitive browsing functions to explore associations at multi-dimensions (metabolite, trait, study, and publication), and constructs knowledge graph to provide overall landscape among cancer, trait, and metabolite. Furthermore, NameToCid (map metabolite name to PubChem Cid) and Enrichment tools are developed to help users enrich the association of metabolites with various cancer types and traits. IMPLICATION: MACdb paves an informative and practical way to evaluate cancer-metabolite associations and has a great potential to help researchers identify key predictive metabolic markers in cancers.

The Application and Efficacy of Second Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia.

BACKGROUND: We retrospectively analyzed the application and clinical efficacy of second allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute leukemia patients who relapsed or had primary graft failure (PGF) after first transplantation. METHODS: From 2007 to 2021, eight patients with acute leukemia who received second allo-HSCT in our hospital were collected, including 6 relapsed patients and 2 patients with PGF after the first HSCT. RESULTS: All the patients received complete donor implantation after second transplantation. The median time of neutrophils and platelet implantation were 12 days (10 days - 13 days) and 23 days (12 days - 123 days). Two cases (25.0%) developed grade II aGVHD, and 4 cases (50.0%) developed cGVHD. Leukemia-free survival (LFS) and overall survival (OS) at 1 year both were 71.4% and at 3 years both were 28.6%. After a median follow-up of 1,556 days (range, 257 - 5,252 days), 3 of the patients (37.5%) survived and 5 (62.5%) died. One patient with NR before second transplantation, treated with a conditioning regime of CLAG-M bridging BuCy, has survived for more than 5 years (61 months). Relapse was the main death reason. CONCLUSIONS: Second allo-HSCT is an effective means to treat acute leukemia patients with relapsed and PGF after first transplantation.