Zeb2 drives the formation of CD11c+ atypical B cells to sustain germinal centers that control persistent infection

CD11c+ atypical B cells (ABCs) are an alternative memory B cell lineage associated with immunization, infection, and autoimmunity. However, the factors that drive the transcriptional program of ABCs have not been identified, and the function of this population remains incompletely understood. Here, we identified candidate transcription factors associated with the ABC population based on a human tonsillar B cell single-cell dataset. We identified CD11c+ B cells in mice with a similar transcriptomic signature to human ABCs, and using an optimized CRISPR-Cas9 knockdown screen, we observed that loss of zinc finger E-box binding homeobox 2 (Zeb2) impaired ABC formation. Furthermore, ZEB2 haplo-insufficient Mowat-Wilson syndrome (MWS) patients have decreased circulating ABCs in the blood. In Cd23Cre/+Zeb2fl/fl mice with impaired ABC formation, ABCs were dispensable for efficient humoral responses after Plasmodium sporozoite immunization but were required to control recrudescent blood-stage malaria. Immune phenotyping revealed that ABCs drive optimal T follicular helper (TFH) cell formation and germinal center (GC) responses and they reside at the red/white pulp border, likely permitting better access to pathogen antigens for presentation. Collectively, our study shows that ABC formation is dependent on Zeb2, and these cells can limit recrudescent infection by sustaining GC reactions.

Evaluation of factors associated with high advanced HIV disease and mortality in Southwestern China: a retrospective cohort study, 2005-2020

OBJECTIVES

To assess the prevalence, all-cause mortality and determinants of advanced HIV disease (AHD) or severe immunosuppression (SIS) in the rural-urban communities of Southwestern China.

STUDY DESIGN

Retrospective cohort study.

METHOD

Data on HIV/AIDS cases reported in 2005-20 were collected from Case Report System. A binary logistic regression model assessed the risk factors of AHD/SIS prevalence. Survival curves across rural-urban regions were compared using Kaplan-Meier estimates and log-rank tests. Determinants of all-cause mortality were identified using the Cox proportional hazard model.

RESULTS

Among 14,533 newly diagnosed HIV/AIDS patients, 7497 (51.6%) presented with AHD and 2564 (17.6%) with SIS. Compared with urban patients, rural patients had a higher prevalence of AHD (56.7% vs 40.7%) and SIS (20.1% vs 12.4%), all-cause mortality (AHD 12.3 vs 5.6, SIS 16.3 vs 5.5, per 100 person-years). Their 5-year survival probability (AHD 59.5% vs 77.1%; SIS 54.4% vs 76.3%) and mean survival time (AHD 106.5 vs 140.6 months, SIS 95.3 vs 144.2 months, p < 0.0001) were lower. Rural patients had an increased risk of SIS prevalence (adjusted odds ratios 1.45, 95% confidence interval [CI] 1.28-1.64; p < 0.0001) and mortality of the total cohort (adjusted hazard ratios 1.41, 95% CI 1.29-1.55; p < 0.0001), AHD cohort (1.38, 1.24-1.54; p < 0.0001), and SIS cohort (1.49, 1.23-1.81; p < 0.0001).

CONCLUSIONS

A high prevalence of AHD/SIS was a severe phenomenon that caused high mortality in rural areas. A regional point-of-care strategy targeting AHD/SIS detection and management is essential for reducing the mortality risk.

Cell death and barrier disruption by clinically used iodine concentrations

Povidone-iodine (PVP-I) inactivates a broad range of pathogens. Despite its widespread use over decades, the safety of PVP-I remains controversial. Its extended use in the current SARS-CoV-2 virus pandemic urges the need to clarify safety features of PVP-I on a cellular level. Our investigation in epithelial, mesothelial, endothelial, and innate immune cells revealed that the toxicity of PVP-I is caused by diatomic iodine (I2), which is rapidly released from PVP-I to fuel organic halogenation with fast first-order kinetics. Eukaryotic toxicity manifests at below clinically used concentrations with a threshold of 0.1% PVP-I (wt/vol), equalling 1 mM of total available I2 Above this threshold, membrane disruption, loss of mitochondrial membrane potential, and abolition of oxidative phosphorylation induce a rapid form of cell death we propose to term iodoptosis. Furthermore, PVP-I attacks lipid rafts, leading to the failure of tight junctions and thereby compromising the barrier functions of surface-lining cells. Thus, the therapeutic window of PVP-I is considerably narrower than commonly believed. Our findings urge the reappraisal of PVP-I in clinical practice to avert unwarranted toxicity whilst safeguarding its benefits.

IgG memory B cells expressing IL4R and FCER2 are associated with atopic diseases

BACKGROUND

Atopic diseases are characterized by IgE antibody responses that are dependent on cognate CD4 T cell help and T cell-produced IL-4 and IL-13. Current models of IgE cell differentiation point to the role of IgG memory B cells as precursors of pathogenic IgE plasma cells. The goal of this work was to identify intrinsic features of memory B cells that are associated with IgE production in atopic diseases.

METHODS

Peripheral blood B lymphocytes were collected from individuals with physician diagnosed asthma or atopic dermatitis (AD) and from non-atopic individuals. These samples were analyzed by spectral flow cytometry, single cell RNA sequencing (scRNAseq), and in vitro activation assays.

RESULTS

We identified a novel population of IgG memory B cells characterized by the expression of IL-4/IL-13 regulated genes FCER2/CD23, IL4R, IL13RA1, and IGHE, denoting a history of differentiation during type 2 immune responses. CD23+ IL4R+ IgG+ memory B cells had increased occurrence in individuals with atopic disease. Importantly, the frequency of CD23+ IL4R+ IgG+ memory B cells correlated with levels of circulating IgE. Consistently, in vitro stimulated B cells from atopic individuals generated more IgE+ cells than B cells from non-atopic subjects.

CONCLUSIONS

These findings suggest that CD23+ IL4R+ IgG+ memory B cells transcribing IGHE are potential precursors of IgE plasma cells and are linked to pathogenic IgE production.

[Feasibility and safety of bridge therapy with active fixed electrodes connected to external permanent pacemakers for patients with infective endocarditis after lead removal and before permanent pacemaker implantation]

Objective: To analyze the feasibility and safety of bridge therapy with active fixed electrodes connected to external permanent pacemakers (AFLEP) for patients with infective endocarditis after lead removal and before permanent pacemaker implantation. Methods: A total of 44 pacemaker-dependent patients, who underwent lead removal due to infective endocarditis in our center from January 2015 to January 2020, were included. According to AFLEP or temporary pacemaker option during the transition period, patients were divided into AFLEP group or temporary pacemaker group. Information including age, sex, comorbidities, indications and types of cardial implantable electionic device (CIED) implantation, lead age, duration of temporary pacemaker or AFLEP use, and perioperative complications were collected through Haitai Medical Record System. The incidence of pacemaker perception, abnormal pacing function, lead perforation, lead dislocation, lead vegetation, cardiac tamponade, pulmonary embolism, death and newly infection of implanted pacemaker were compared between the two groups. Pneumothorax, hematoma and the incidence of deep vein thrombosis were also analyzed. Results: Among the 44 patients, 24 were in the AFLEP group and 20 in the temporary pacemaker group. Age was younger in the AFLEP group than in the temporary pacemaker group (57.5(45.5, 66.0) years vs. 67.0(57.3, 71.8) years, P=0.023). Male, prevalence of hypertension, diabetes mellitus, chronic renal dysfunction and old myocardial infarction were similar between the two groups (all P>0.05). Lead duration was 11.0(8.0,13.0) years in the AFLEP group and 8.5(7.0,13.0) years in the temporary pacemaker group(P=0.292). Lead vegetation diameter was (8.2±2.4)mm in the AFLEP group and (9.1±3.0)mm in the temporary pacemaker group. Lead removal was successful in all patients. The follow-up time in the AFLEP group was 23.0(20.5, 25.5) months, and the temporary pacemaker group was 17.0(14.5, 18.5) months. In the temporary pacemaker group, there were 2 cases (10.0%) of lead dislocation, 2 cases (10.0%) of sensory dysfunction, 2 cases (10.0%) of pacing dysfunction, and 2 cases (10.0%) of death. In the AFLEP group, there were 2 cases of abnormal pacing function, which improved after adjusting the output voltage of the pacemaker, there was no lead dislocation, abnormal perception and death. Femoral vein access was used in 8 patients (40.0%) in the temporary pacemaker group, and 4 patients developed lower extremity deep venous thrombosis. There was no deep venous thrombosis in the AFLEP group. The transition treatment time was significantly longer in the AFLEP group than in the temporary pacemaker group (19.5(16.0, 25.8) days vs. 14.0(12.0, 16.8) days, P=0.001). During the follow-up period, there were no reinfections with newly implanted pacemakers in the AFLEP group, and reinfection occurred in 2 patients (10.0%) in the temporary pacemaker group. Conclusions: Bridge therapy with AFLEP for patients with infective endocarditis after lead removal and before permanent pacemaker implantation is feasible and safe. Compared with temporary pacemaker, AFLEP is safer in the implantation process and more stable with lower lead dislocation rate, less sensory and pacing dysfunction.

[Safety and efficacy of high-power, short-duration superior vena cava isolation in combination with conventional radiofrequency ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial]

Objective: For patients with paroxysmal atrial fibrillation, superior vena cava isolation on the basis of pulmonary vein isolation may further improve the long-term success rate of radiofrequency ablation. We aimed to explore the efficacy and safety of superior vena cava isolation by high-power and short-duration (HPSD) ablation plus conventional radiofrequency ablation (RA) in patients with paroxysmal atrial fibrillation. Methods: It was a prospective randomized controlled study. From January 1, 2019 to June 1, 2020, 180 patients who underwent radiofrequency ablation for paroxysmal atrial fibrillation in our center were consecutively screened. Patients were eligible if there was a trigger potential and the muscle sleeve length was greater than 3 cm. A total of 60 eligible patients were finally included and randomly divided into HPSD group (HPSD plus RA) and common power and duration (CPD) group (CPD plus RA) by random number table method (n=30 in each group). Efficacy was evaluated by ablation points, isolation time and ablation time. Safety was evaluated by the incidence of POP, cardiac tamponade, phrenic nerve injury, sinoatrial node injury and all-cause. Results: Superior vena cava isolation was achieved by 14 (13, 15) points in the HPSD group, which was significantly less than that in the CPD group (20(18, 22), P<0.001). The superior vena cava isolation time was 8 (7, 9) minutes in the HPSD group, which was significantly shorter than in the CPD group (17(14, 20) minutes, P<0.001). The average ablation time significantly shorter in HPSD group than in CPD group (78.0(71.1, 80.0) s vs. 200(167.5, 212.5)s, P<0.001). The average impedance drop was more significant in the HPSD group than in the CPD group (20.00(18.75, 21.00)Ω (and the percentage of impedance drop was 15%) vs. 12.00(11.75, 13.25)Ω (the percentage of impedance decrease was 12%), P<0.001). There was 1 POP (3.3%) in the HPSD group, and 3 POPs (10.0%) in the CPD group (P>0.05). There was no cardiac tamponade, phrenic nerve injury, sinoatrial node injury and death in both groups. Conclusions: HPSD technique for the isolation of superior vena cava is safe and effective in patients with paroxysmal atrial fibrillation undergoing conventional radiofrequency ablation.

[Effect of Li's catheter in the cardiac resynchronization therapy implantation]

Objective: To evaluate the effect of Li's catheter in cardiac resynchronization therapy (CRT) implantation. Methods: This study was a retrospective cohort study. Patients with indications for CRT implantation who visited the Department of Cardiology, Peking University People's Hospital from January 1, 2016 to January 1, 2022 were enrolled. Patients were divided into Li's catheter group (CRT implantation with Li's catheter) and control group (CRT implantation with the traditional method). The general clinical data of the patients were obtained through the electronic medical record system. Li's catheter is a new type of coronary sinus angiography balloon catheter independently developed by Dr. Li Xuebin (patent number: 201320413174.1). The primary outcome was the success rate of CRT device implantation, and the secondary outcomes included efficacy and safety parameters. Efficacy indicators included operation time, coronary sinus angiography time, left ventricular lead implantation time, X-ray exposure time, left ventricular lead threshold, and diaphragm stimulation. Safety outcomes included incidence of coronary sinus dissection, cardiac tamponade, and pericardial effusion. Results: A total of 170 patients were enrolled in this study, including 90 in Li's catheter group and 80 in control group. Age, male proportion of patients, proportion of patients with ischemic cardiomyopathy, hypertension, diabetes mellitus, chronic renal insufficiency, New York Heart Association (NYHA) functional classification, left ventricular ejection fraction, left ventricular end-diastolic diameter, proportion of left bundle branch block, and preoperative QRS wave width were similar between the two groups (all P>0.05). In Li's catheter group, 34 cases (37.8%) implanted with CRT defibrillators, and 28 cases (35.0%) implanted with CRT defibrillators in control group, the difference was not statistically significant (P=0.710). The success rate of CRT device implantation in Li's catheter group was 100% (90/90), which was significantly higher than that in control group (93.8%, 75/80, P=0.023).The operation time was 57.0 (52.0, 62.3) minutes, the time to complete coronary sinus angiography was 8.0 (6.0, 9.0) minutes, and the time of left ventricular electrode implantation was 8.0 (7.0, 9.0) minutes in Li's catheter group, and was 91.3 (86.3, 97.0), 18.0 (16.0, 20.0), 25.0 (22.0, 27.7) minutes respectively in control group, all significantly shorter in Li's catheter group (all P<0.05). The exposure time of X-ray was 15.0 (14.0, 17.0) minutes in Li's catheter group, which was also significantly shorter than that in control group (32.5 (29.0, 36.0) minutes, P<0.001). There was no coronary sinus dissection and cardiac tamponade in Li's catheter group, and 1 patient (1.1%) had diaphragmatic stimulation in Li's catheter group. In control group, 6 patients (6.7%) had coronary sinus dissection, and 1 patient (1.1%) developed pericardial effusion, and 3 patients (3.3%) had diaphragmatic stimulation. The incidence of coronary sinus dissection in Li's catheter group was significantly lower than that in control group (P=0.011). The postoperative left ventricular thresholds in Li's catheter group and control group were similar (1.80 (1.60, 2.38) V/0.5 ms vs. 1.80 (1.60, 2.40) V/0.5 ms, P=0.120). Conclusions: Use of Li's catheter is associated with higher success rate of CRT implantation, short time of coronary sinus angiography and left ventricular electrode implantation, reduction of intraoperative X-ray exposure, and lower incidence of coronary vein dissection in this patient cohort.

[Value of D-dimer and left atrial size combined with CHA2DS2-VASc score in excluding left atrial thrombosis in patients with non-valvular atrial fibrillation]

Objective: To investigate the related factors of thrombosis in patients with non-valvular atrial fibrillation (NVAF), and whether the combination of D-dimer, left atrial anteroposterior diameter and CHA₂DS₂-VASc score can be used to exclude left atrial thrombosis. Methods: A total of 75 NVAF patients with left atrial thrombosis confirmed by transesophageal echocardiography in Peking University People's Hospital from January 1, 2015 to December 31, 2019 were enrolled as the thrombus group. From January 1 to October 31, 2019, 80 patients with NVAF without left atrial thrombosis were enrolled as the control group. The clinical data, CHA₂DS₂-VASc score, hematological biomarkers, ultrasound data of two groups were compared. The independent factors associated with left atrial thrombosis were screened by univariate analysis and multivariate logistic regression analysis. The positive predictive value and negative predictive value for the diagnosis of left atrial thrombosis were gained by the score calculated based on the independent related factors. Results: There were no significant differences in age, gender, proportion of persistent atrial fibrillation and duration of atrial fibrillation between the two groups. The CHA₂DS₂-VASc score [M (Q₁, Q₃)] of the thrombus group was higher than that of the control group [2.5 (1.0, 3.0) vs 1.8 (1.0, 3.0), P=0.012]. The prothrombin time activity [M (Q₁, Q₃)] of the thrombus group was 81.1 (72.0, 93.0)%, which was lower than that of the control group 88.8 (83.0,96.0)% (P=0.008). The activated partial thromboplastin time (APTT) of the thrombus group was longer than that of the control group [(32.1±4.8) s vs (30.2±3.7) s, P=0.006]. D-dimer [M (Q₁, Q₃)] of the thrombus group was 231.0 (71.5, 272.2) ng/ml, which was higher than that of the control group 121.7 (49.0, 140.0) ng/ml (P<0.001). The left atrial anteroposterior diameter in thrombus group was larger [(44.6±6.6) mm vs (38.9±5.3) mm, P<0.001], the proportion of mitral regurgitation was higher (58.1% vs 26.8%, P<0.001). The left ventricular ejection fraction [M (Q₁, Q₃)] of the thrombus group was 56.7% (45.8%, 66.3%), which was lower than that of the control group 63.3% (60.5%, 70.2%) (P=0.003). Multivariate logistic regression analysis showed that the factor related to left atrial thrombosis was left atrial anteroposterior diameter (OR=4.480, 95%CI: 1.616-12.423). The negative predictive value of the new scoring system combined with D-dimer, left atrial anteroposterior diameter and CHA₂DS₂-VASc score for left atrial thrombosis was 100%. Conclusions: In NVAF patients, the factor independently associating with left atrial thrombosis is left atrial anteroposterior diameter. The combination of D-dimer, left atrial anteroposterior diameter, and CHA₂DS₂-VASc score can help exclude left atrial thrombosis before ablation of NVAF.

[The effect of peripheral blood cell score on the prognosis of multiple myeloma patients treated with bortezomib]

目的

评估外周血细胞检测结果在以硼替佐米为一线治疗的多发性骨髓瘤（MM）患者中的预后作用。

方法

回顾性分析2014年1月至2016年12月浙江大学医学院附属第一医院和浙江省舟山医院收治的155例初诊MM患者的临床数据，患者均一线接受以硼替佐米为基础方案的治疗。分析外周血细胞检测结果，包括ANC、单核细胞计数（AMC）、HGB、红细胞平均体积（MCV）、PLT以及其他临床特征对MM患者的预后评估作用。

结果

AMC（>0.6×10⁹/L）、MCV（>99.1fl）以及PLT（<150×10⁹/L）明显影响MM患者无进展生存（PFS）和总生存（OS），以上3个因子分别赋值1分，形成血细胞积分。结果显示，64例（41.3％）积分0，57例（36.8％）积分1，32例（20.6％）积分2，2例（1.3％）积分3，4组患者中位PFS时间分别为42.8、26.5、15.8、6.4个月（P<0.001），中位OS时间分别为未达到和48.2、31.1、31.4个月（P＝0.001）。多因素分析提示，血细胞积分（2～3对0～1）和骨髓浆细胞比例（>30％对≤30％）为PFS的独立预后因素（HR分别为1.95和1.76），而患者年龄（>65岁对≤65岁）、R-ISS分期（Ⅲ期对Ⅰ～Ⅱ期）和血细胞积分（2～3对0～1）是OS的独立预后因素（HR分别为2.08、2.13和2.12）。

结论

血细胞积分简单易得，可用于新药时代初治MM患者的预后评估，但仍需扩大病例并进行前瞻性研究进一步明确。

Abstract LB-A12: A synthetic lethal drug screen identifies exploitable vulnerabilities in cohesin-deficient cells

The cohesin complex comprises four core subunits: RAD21, SMC3, SMC1A, and STAG2. Cohesin is required for many biological processes, including sister chromatid cohesion, DNA damage response, regulation of gene expression, and ribosomal biogenesis. Germline mutations of cohesin subunits or their regulators give rise to human developmental disorders, while somatic mutations in cohesin subunits are found in a wide range of human cancers, including acute myeloid leukemia (AML) (12%), Ewing sarcoma (15%) and glioblastoma (19%). In particular, cohesin subunit STAG2, has been identified as one of only 12 genes that are significantly mutated in more than 4 human cancers. Currently, there is no targeted therapeutic strategy for cancer patients with cohesin mutations. Synthetic lethality has emerged as a promising approach for targeted therapy. While synthetic lethal interactions of STAG2 have been demonstrated with its paralog, STAG1, and with the DNA damage repair pathway, synthetic lethal interactions with other pathways have not been explored. To identify synthetic lethal drug activity with cohesin mutations, we generated three isogenic cohesin-deficient MCF10A cell lines (RAD21+/-, SMC3+/-, and STAG2-/-) using CRISPR/Cas9. Cohesin-deficient MCF10A cell lines are sufficiently similar to their parental line concerning growth rate and chromosome stability. However, these cell lines exhibit alterations in nucleolar morphology and increased nuclear location of γH2AX and p53 (except in STAG2-/-). RNA-sequencing analysis of the cell lines showed that cohesin subunit mutation led to downregulation of genes involved in regulation of ribosome biogenesis and RNA processing. Furthermore, ribosomal stress mediated by Actinomycin D led to severe nucleolar fragmentation in cohesin-deficient MCF10A, but not MCF10A parental, suggesting that cohesin mutation might confer vulnerability to perturbation of ribosome biogenesis. Using MCF10A parental and isogenic cohesin-deficient MCF10A cell lines, we performed a quantitative high-throughput drug screen against 3,009 compounds of FDA-approved drugs, kinase, and epigenetic inhibitors. Several classes of inhibitors targeting mTOR signaling, Wnt signaling and chromatin modification were found to selectively inhibit the growth of cohesin-deficient MCF10A cells by 30% or more. WAY-600 (mTORC1/mTORC2 inhibitor) and I-BET-762 (Bromodomain inhibitor) were among the top hits. Mechanistic studies on how these drugs preferentially kill cohesin-deficient cells are under way. In summary, we have identified potential synthetic lethal compounds that may provide the basis for development of targeted therapies of cancers with cohesin deficiency or mutation.

Citation Format: Chue Vin Chin, Jisha Antony, Amee J George, JinShu He, Kate Parson, Ross D Hannan, Julia A Horsfield. A synthetic lethal drug screen identifies exploitable vulnerabilities in cohesin-deficient cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr LB-A12. doi:10.1158/1535-7163.TARG-19-LB-A12

High-Content Imaging Approaches to Quantitate Stress-Induced Changes in Nucleolar Morphology

The nucleolus is a dynamic subnuclear compartment that has a number of different functions, but its primary role is to coordinate the production and assembly of ribosomes. For well over 100 years, pathologists have used changes in nucleolar number and size to stage diseases such as cancer. New information about the nucleolus' broader role within the cell is leading to the development of drugs which directly target its structure as therapies for disease. Traditionally, it has been difficult to develop high-throughput image analysis pipelines to measure nucleolar changes due to the broad range of morphologies observed. In this study, we describe a simple high-content image analysis algorithm using Harmony software (PerkinElmer), with a PhenoLOGIC™ machine-learning component, that can measure and classify three different nucleolar morphologies based on nucleolin and fibrillarin staining ("normal," "peri-nucleolar rings" and "dispersed"). We have utilized this algorithm to determine the changes in these classes of nucleolar morphologies over time with drugs known to alter nucleolar structure. This approach could be further adapted to include other parameters required for the identification of new therapies that directly target the nucleolus.

MMS observations of electron scale magnetic cavity embedded in proton scale magnetic cavity

Magnetic cavities (sometimes referred to as magnetic holes) at electron kinetic scale are thought to be one of the extremely small intermittent structures formed in magnetized turbulent plasmas, where the turbulence energy cascaded down to electron scale may finally be dissipated and consequently energize the electrons. However, the geometry and formation of these structures remain not definitively resolved. Here we discuss an electron scale magnetic cavity embedded in a proton scale magnetic cavity observed by the MMS spacecraft in the magnetosheath. By applying an innovative particle sounding technique, we directly depict the boundary of the electron scale magnetic cavity and uncover the geometry. We find that this structure is nearly circular with a radius of 10.0 km and its formation is due to the diamagnetic current. Investigation of the electron scale structure is only recently made possible by the high spatial and temporal resolution provided by MMS observations.

[The effect of WT1 expression on the prognosis of allogeneic hematopoietic stem cell transplantation in acute leukemia]

Objective: To study the effect of WT1 expression on the prognosis of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute leukemia (AL) and its significance as molecular marker to dynamically monitor minimal residual disease (MRD) . Methods: Retrospectively analyzed those AL patients who underwent allo-HSCT in the First Hospital Affiliated to Zhejiang University School of Medicine during Jan 2016 to Dec 2017, a total number of 314 cases, 163 males and 151 females, median age was 30 (9-64) years old. Comparing the difference of WT1 expression at diagnosed, pre-HSCT and after HSCT. Using the receiver operating characteristic (ROC) curve to determine the WT1 threshold at different time so as to predict relapse. The threshold of WT1 expression before transplantation was 1.010%, within 3 months after HSCT was 0.079% and 6 months after HSCT was 0.375%. According to these thresholds, WT1 positive patients were divided into low expression groups and high expression groups. Analyzed the relationship between overall survival (OS) , disease-free survival (DFS) , cumulative incidence of relapse (CIR) and WT1 expression. Results: The OS and DFS of high expression group pre-HSCT were lower than low expression group [69.2% (9/13) vs 89.1% (57/64) , χ(2)=4.086, P=0.043; 53.8% (7/13) vs 87.5% (56/64) , χ(2)=9.766, P=0.002], CIR was higher than low expression group [30.8% (4/13) vs 7.8% (5/64) , P=0.017]. There was no significant difference of OS and DFS between high expression and low expression group of 3 months after HSCT (P=0.558, P=0.269) . The OS and DFS of high expression group of 6 months after transplantation were both lower than low expression group (P=0.049, P=0.035) . Multivariate analysis showed that WT1>0.375% when 6 months after transplantation was the only independent prognostic factor for shorter DFS (P=0.022) . There was no statistically significant difference in CIR between the high-expression group and the low-expression group 3 months after transplantation and 6 months after transplantation (P=0.114, P=0.306) . Conclusion: High expression of WT1 before and after HSCT was an adverse prognosis factor. It is of clinical practical value to use WT1 as a transplant recommendation index for patients with acute leukemia and as a marker to monitor MRD dynamically.

IgG1 memory B cells keep the memory of IgE responses

The unique differentiation of IgE cells suggests unconventional mechanisms of IgE memory. IgE germinal centre cells are transient, most IgE cells are plasma cells, and high affinity IgE is produced by the switching of IgG1 cells to IgE. Here we investigate the function of subsets of IgG1 memory B cells in IgE production and find that two subsets of IgG1 memory B cells, CD80+CD73+ and CD80-CD73-, contribute distinctively to the repertoires of high affinity pathogenic IgE and low affinity non-pathogenic IgE. Furthermore, repertoire analysis indicates that high affinity IgE and IgG1 plasma cells differentiate from rare CD80+CD73+ high affinity memory clones without undergoing further mutagenesis. By identifying the cellular origin of high affinity IgE and the clonal selection of high affinity memory B cells into the plasma cell fate, our findings provide fundamental insights into the pathogenesis of allergies, and on the mechanisms of antibody production in memory B cell responses.IgE is an important mediator of protective immunity as well as allergic reaction, but how high affinity IgE antibodies are produced in memory responses is not clear. Here the authors show that IgE can be generated via class-switch recombination in IgG1 memory B cells without additional somatic hypermutation.

[A prospective study of the efficacy and safety of maintenance therapy with recombinant human thrombopoietin in patients with primary immune thrombocytopenia: a multicenter study]

Objective: To evaluate the efficacy and safety of maintenance therapy with reduced dose of rhTPO in the patients with primary immune thrombocytopenia (ITP) who attained stable platelet (PLT) counts after daily administration of rhTPO. Methods: Treatment was started with a daily administration of rhTPO (300 U/kg) for 2 consecutive weeks. Patients who attained stable PLT≥50×10(9)/L were enrolled to maintenance therapy starting with every other day administration of rhTPO, then adjusted dose interval to maintain platelet count (30-100) ×10(9)/L. Results: A total of 91 eligible patients were enrolled. Fourteen patients discontinued the study due to noncompliance (12/14) and investigator decision (2/14) . Among 77 patients who completed the study, 38 patients with the administration of rhTPO at every other day or less could maintain PLT≥30×10(9)/L for 12 weeks. The percentage of patients with a platelet response (PLT≥30×10(9)/L) at 4(th) week, 8(th) week and 12(th) week of maintain therapy was 92.6% (63/68) , 82.7% (43/52) and 85.0% (34/40) , respectively. Median platelet counts remained in the range of (70-124) ×10(9)/L. The overall incidence of rhTPO-related adverse events was 7.7%. All the adverse events were generally mild. Conclusion: Extending the dose interval of rhTPO is feasible to maintain stable platelet count in the patients with ITP, but the optimal dose interval is uncertain and might vary with individuals.

The distinctive germinal center phase of IgE+ B lymphocytes limits their contribution to the classical memory response

Direct class switching to IgE generates IgE⁺ GC cells that are highly apoptotic and do not contribute to the memory compartment, while sequential switching through an IgG⁺ intermediate results in the generation of long-lived IgE⁺ plasma cells.

The mechanisms involved in the maintenance of memory IgE responses are poorly understood, and the role played by germinal center (GC) IgE⁺ cells in memory responses is particularly unclear. IgE⁺ B cell differentiation is characterized by a transient GC phase, a bias toward the plasma cell (PC) fate, and dependence on sequential switching for the production of high-affinity IgE. We show here that IgE⁺ GC B cells are unfit to undergo the conventional GC differentiation program due to impaired B cell receptor function and increased apoptosis. IgE⁺ GC cells fail to populate the GC light zone and are unable to contribute to the memory and long-lived PC compartments. Furthermore, we demonstrate that direct and sequential switching are linked to distinct B cell differentiation fates: direct switching generates IgE⁺ GC cells, whereas sequential switching gives rise to IgE⁺ PCs. We propose a comprehensive model for the generation and memory of IgE responses.

Generating mechanism for higher-order rogue waves

We introduce a mechanism for generating higher-order rogue waves (HRWs) of the nonlinear Schrödinger (NLS) equation: the progressive fusion and fission of n degenerate breathers associated with a critical eigenvalue λ(0) creates an order-n HRW. By adjusting the relative phase of the breathers in the interacting area, it is possible to obtain different types of HRWs. The value λ(0) is a zero point of an eigenfunction of the Lax pair of the NLS equation and it corresponds to the limit of the period of the breather tending to infinity. By employing this mechanism we prove two conjectures regarding the total number of peaks, as well as a decomposition rule in the circular pattern of an order-n HRW.

Breather and rogue wave solutions of a generalized nonlinear Schrödinger equation

In this paper, using the Darboux transformation, we demonstrate the generation of first-order breather and higher-order rogue waves from a generalized nonlinear Schrödinger equation with several higher-order nonlinear effects representing femtosecond pulse propagation through nonlinear silica fiber. The same nonlinear evolution equation can also describe the soliton-type nonlinear excitations in classical Heisenberg spin chain. Such solutions have a parameter γ(1), denoting the strength of the higher-order effects. From the numerical plots of the rational solutions, the compression effects of the breather and rogue waves produced by γ(1) are discussed in detail.

CTLs contain and use intracellular stores of FasL distinct from cytolytic granules

CTL lyse target cells through the release of cytolytic granule contents and cell surface expression of Fas ligand (FasL). Current models suggest that FasL is stored in cytolytic granules and that FasL cell surface expression would be subject to the same controls as degranulation. We demonstrate that murine CTLs undergo two waves of FasL cell surface expression after stimulation. The first wave is from a pre-existing pool of FasL, and the second wave requires new protein synthesis. Signaling for FasL expression appears to be finely tuned as a weak signal preferentially induced surface translocation of the stored FasL, whereas a strong signal preferentially triggered the expression of de novo synthesized FasL. The early FasL is differentially regulated from degranulation, as there were multiple circumstances whereby rapid FasL cell surface expression and FasL-dependent killing occurred in the absence of detectable degranulation. Furthermore, we found through confocal microscopy that stored FasL resides in vesicles distinct from cytolytic granules. Our data clearly show that CTL degranulation and FasL lytic mechanisms are fully independent with respect to stored component localization and regulation.

Cytotoxic T lymphocytes express intracellular stores of FasL via mechanisms distinct from cytolytic granule exocytosis (B16)

Cytotoxic T lymphocytes (CTL) lyse target cells through the release of cytolytic granules and cell surface expression of Fas ligand (FasL). We found that there is prestored FasL pool in CTL, which underwent rapid TCR-regulated cell surface expression upon target cell engagement. Current models suggest that FasL is stored in cytolytic granules and that FasL cell surface expression would be subject to the same control as degranulation. The aim of the current study is to investigate if degranulation of cytolytic granules and FasL expression pathways of CTL are controlled by differential mechanisms. FasL cell surface expression and degranulation, as measured by CD107a cell surface expression in CTLs were compared by flow cytometry under different conditions. FasL underwent an immediate and transient cell surface delivery following either TCR stimulation by anti-CD3 antibody crosslinking, or phorbol ester treatment, conditions that do not permit degranulation. Furthermore, treatment with pharmacological reagents indicated that the preformed FasL cell surface transport is PI3-kinase (PI3K)-, calcineurin- and microtubule-independent, which are all indispensable for degranulation. Finally, stored FasL resides in vesicles distinct from cytolytic granules as assessed by confocal microscopy and subcellular fractionation. Our data clearly show that CTL degranulation and FasL lytic mechanisms are fully independent with respect to regulation and localization.

This work was funded by the Canadian Institutes of Health Research (CIHR).

A novel PKC regulates ERK activation and degranulation of cytotoxic T lymphocytes: Plasticity in PKC regulation of ERK

Stimulation of cytotoxic T lymphocyte (CTL) degranulation with plate-bound anti-CD3 Ab leads to two phases of ERK activation: an early PKC-independent phase followed by a later sustained PKC-dependent phase. Herein, we show that a novel PKC (nPKC) mediates the late phase of ERK activation, upstream of Ras in murine T cells. In contrast, when CTL are activated with cross-linked anti-CD3 Ab, which does not trigger CTL degranulation, there is a requirement for conventional PKC (cPKC) for ERK activation. We detect increased novel PKCtheta activation only when CTL are stimulated with plate-bound Ab and not cross-linked Ab. Interestingly, in T cells from mice lacking PKCtheta, sustained ERK activation requires the activity of cPKC, implying that PKCtheta is required for the nPKC pathway that normally mediates sustained ERK activation. CTL lines derived from PKCtheta-deficient mice degranulate and activate ERK normally, and exhibit altered expression of PKC isozymes, which may compensate for the loss of PKCtheta. Taken together, these data demonstrate that normally an nPKC participates in the sustained activation of ERK. However, if the nPKC pathway is compromised, alternate PKC pathways can compensate, suggesting that considerable plasticity exists with respect to PKC regulation of ERK activation in T cells.

A gallic acid derivative and polysaccharides with antioxidative activity from rose (Rosa rugosa) flowers

In this study, the major antioxidant components of rose flower were identified. An aqueous extract of rose flowers was chromatographed on CM-cellulose in ammonium acetate buffer (10 mM, pH 4.5) to yield three un-adsorbed peaks F1, F2 and F3. Each of these peaks was subjected to gel filtration on Sephadex G75. F1 yielded two peaks, whereas both F2 and F3 gave rise to only a single peak. Spectroscopic studies using NMR and FTIR revealed that F3 is a gallic acid derivative. It exhibited the highest antioxidative potency. F1-a derived from F1 by gel filtration is mainly a polysaccharide-peptide complex with less potent antioxidative activity. F2 is a polysaccharide also with reduced antioxidant activity. This study demonstrates, for the first time, the presence of both gallic acid derivatives and polysaccharides as major antioxidant principles of the aqueous extract of rose flowers.

[Immunohistochemical analysis of protein gene product 9.5, a new marker for parietal epithelial cells of Bowman's capsules, in anti-glomerular basement membrane(GBM) antibody induced glomerulonephritis of WKY rats]

Protein gene product 9.5(PGP 9.5) is expressed specifically in neuroendocrine cells and considered to be one of the neuroendocrine markers. Recently, we reported that PGP 9.5 is localized in the parietal epithelial cells(PECs) of Bowman's capsules as well as in neural tissues. In the present study, immunohistochemical analysis of PGP 9.5 as a specific marker of the PECs of Bowman's capsules, synaptopodin as a podocyte-specific marker, and ED-1 as a specific marker of monocytes/macrophages was performed in the cellular crescents in anti-GBM antibody induced glomerulonephritis of WKY rats using serial renal sections. In the acute phase of anti-GBM antibody induced glomerulonephritis, and the expression of PGP 9.5 and ED-1 was observed diffusely in proliferating cells of cellular crescents. However, in most part of cellular crescents, PGP 9.5 positive areas did not overlap with the ED-1 positive areas. Synaptopodin was constantly detected along the glomerular tufts compressed by the crescents. In the chronic phase of this disease, PGP 9.5 was observed in the cells covering the surface of fibrous crescents or scattered within fibrocellular crescents. Synaptopodin was partially detected in such cells. It appears that cellular crescents are composed mainly of proliferating PECs and macrophages in rat anti-GBM antibody-induced glomerulonephritis.

Identification of cellular origin of type I collagen in glomeruli of rats with crescentic glomerulonephritis induced by anti-glomerular basement membrane antibody

BACKGROUND

Type I collagen is an interstitial collagen, which is not present in normal glomeruli. As type I collagen was observed in advanced glomerular lesions, it appears to be associated with deterioration of renal function. However, the origins of cells expressing type I collagen mRNA in glomeruli of diseased kidneys remains controversial.

METHODS

We examined the expression of type I collagen in glomeruli at protein and mRNA levels in rat crescentic glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody. In addition, in situ hybridization and immunohistochemical staining of serial sections were performed to identify the cellular origin of type I collagen in glomeruli.

RESULTS

Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) in isolated glomeruli showed that mRNA expression of type I collagen was remarkably increased on days 7, 14, and 28 after anti-GBM antibody injection (12.2+/-1.4, 20.2+/-2.1 and 14.6+/-1.0-fold over day 0, respectively). Immunofluorescence for type I collagen demonstrated marked staining in the fibrocellular and fibrous crescents, and weak staining within glomerular mesangial areas. In close association with mRNA levels analysed by RT-PCR, in situ hybridization revealed predominant presence of alpha1(I) collagen mRNA in cells within crescentic areas and Bowman's capsules. Serial section analysis for immunostaining and in situ hybridization showed that some alpha1(I) collagen mRNA-positive cells were also positive for cytokeratin. In contrast, no alpha1(I) collagen mRNA-positive cells were stained by ED-1 and podocalyxin.

CONCLUSIONS

It appears that increased expression of type I collagen at the protein and mRNA levels in glomeruli is involved in the progression of glomerulonephritis. At least in this crescentic model, parietal epithelial cells (PECs) may partially contribute to the dysregulated production of type I collagen, which leads to glomerulosclerosis.

The molecular cloning and characterization of BM1P1 and BM1P2 proteins, putative positive transcription factors involved in barbiturate-mediated induction of the genes encoding cytochrome P450BM-1 of Bacillus megaterium

Analysis of a 1.3-kilobase segment of 5'-flanking DNA from the barbiturate-inducible P450BM-1 gene (CYP106) of Bacillus megaterium revealed two open reading frames. One, BM1P1, encodes 98 amino acids and is located 267 base pairs upstream from the sequence encoding cytochrome P450BM-1 but in the opposite orientation. The second, BM1P2 (88 amino acids), is 892 base pairs upstream from the P450BM-1 coding sequence and in the same coding strand. The expression of BM1P1 and BM1P2 was strongly stimulated in cells grown in the presence of pentobarbital, and the BM1P1 gene product exerted positive control on expression of P450BM-1. When a 177-base pair fragment encompassing the overlapping promoter regions of the P450BM-1 and BM1P1 genes was used as a probe in DNA binding assays, the BM1P1 and BM1P2 gene products and Bm3R1 (the repressor protein regulating the barbiturate-mediated expression of P450BM-3) could bind individually, but the addition of BM1P1 or BM1P2 to a binding mixture containing Bm3R1 completely prevented the appearance of a Bm3R1 binding band. When a 208-base pair fragment containing a Barbie box sequence and located upstream of the 177-base pair fragment was used as a probe, only a Bm3R1 binding band was detected. Although neither BM1P1 and BM1P2 appeared to bind to this 208-base pair fragment, their presence strongly inhibited the binding of Bm3R1 to the same probe. The evidence suggests that BM1P1 and BM1P2 may, in part, act as positive regulatory proteins involved in the expression of the P450BM-1 gene by interfering with the binding of the repressor protein, Bm3R1, to the regulatory regions of P450BM-1.

The role of Barbie box sequences as cis-acting elements involved in the barbiturate-mediated induction of cytochromes P450BM-1 and P450BM-3 in Bacillus megaterium

In a previous publication (He, J.-S., and Fulco, A. J. (1991) J. Biol. Chem. 266, 7864-7869), we reported that a 15-17-base pair DNA sequence (designated a Barbie box element) in the 5'-regulatory regions of cytochrome P450BM-1 and P450BM-3 genes from Bacillus megaterium was recognized by a barbiturate-regulated protein. It is now recognized that essentially all eukaryotic and prokaryotic genes whose 5'-flanking regions are known and that encode barbiturate-inducible proteins contain the Barbie box element. A 4-base pair sequence (AAAG) is found in the same relative position in all Barbie box elements. In B. megaterium, mutation of the Barbie box located in the P450BM-1 gene leads to the constitutive synthesis of cytochrome P450BM-1 and a 10-fold increase of expression of Bm1P1, a small gene located upstream of the P450BM-1 gene, that encodes a putative regulatory protein. Mutation of the P450BM-3 Barbie box significantly increased the expression of both P450BM-3 and Bm3P1 (another small gene located upstream of the P450BM-3 gene that encodes a second putative regulatory protein) in response to pentobarbital induction but left the basal levels unaffected. In gel mobility shift assays, Bm3R1, a repressor of the P450BM-3 gene, was found to specifically interact with the Barbie box sequences of the B. megaterium P450 genes. Mutated Barbie boxes showed a decreased binding affinity for Bm3R1 compared to their wild type (unmutated) counterparts. Barbie box sequences were also shown to specifically interact with putative positive regulatory factors of B. megaterium cells. These putative positive factors were induced by pentobarbital and were also present at high levels during late stationary phase of B. megaterium cell cultures grown in the absence of barbiturates. The mutated Barbie box sequences had greater binding affinity for these positive factors than did unmutated Barbie box sequences. DNase I footprinting analysis of the 5'-flanking region of the P450BM-1 gene revealed that these positive factors protected a segment of DNA covering a portion of the Barbie box sequence and a small flanking region. Similar footprinting experiments with the 5'-flanking region of the P450BM-3 gene failed, however, to unambiguously reveal protected sequences in the Barbie box region. The evidence suggests that the positive factors and Bm3R1 compete with each other for binding to the Barbie box region, especially in the 5'-flanking region of the P450BM-1 gene, and for putative roles in the regulation of transcription from the B. megaterium P450 genes.(ABSTRACT TRUNCATED AT 400 WORDS)

A barbiturate-regulated protein binding to a common sequence in the cytochrome P450 genes of rodents and bacteria

Analyses of the 5' regulatory sequences of genes encoding barbiturate-inducible cytochromes P450BM-1 and P450BM-3 from Bacillus megaterium and of the 5' sequences of genes for barbiturate-inducible P450b and P450e of the rat revealed a string of 17 base pairs in each of the genes that shared a high degree of sequence identity. Labeled oligonucleotide probes of each of these four sequences were tested in gel retardation assays with protein obtained from B. megaterium grown either in the presence or absence of barbiturates or with protein from nuclear extracts from livers of rats left untreated or injected with phenobarbital. Each of the four 17-mers bound strongly to a single protein from bacteria grown in the absence of barbiturates, but this binding was dramatically reduced with protein from pentobarbital- or phenobarbital-grown cells. Conversely, the probes complexed weakly to one protein band from nuclear extracts from untreated rats but much more strongly with protein from phenobarbital-treated rats. Similar effects could be obtained by prolonged incubation with phenobarbital of either soluble protein from the bacteria grown in the absence of barbiturates or nuclear extract protein from untreated rats. Deletion analysis of the 5'-flanking region of the P450BM-1 gene of B. megaterium revealed a putative repressor binding site located within a 24-base pair DNA segment that included the 17-base pair sequence involved in barbiturate-regulated protein binding.

Molecular cloning, coding nucleotides and the deduced amino acid sequence of P-450BM-1 from Bacillus megaterium

The gene encoding barbiturate-inducible cytochrome P-450BM-1 from Bacillus megaterium ATCC 14581 has been cloned and sequenced. An open reading frame in the 1.9 kb of cloned DNA correctly predicted the NH2-terminal sequence of P-450BM-1 previously determined by protein sequencing, and, in toto, predicted a polypeptide of 410 amino acid residues with an Mr of 47,439. The sequence is most, but less than 27%, similar to that of P-450CAM from Pseudomonas putida, so that P-450BM-1 clearly belongs to a new P-450-gene family, distinct especially from that of the P-450 domain of P-450BM-3, a barbiturate-inducible single polypeptide cytochrome P-450:NADPH-P-450 reductase from the same strain of B. megaterium (Ruettinger, R.T., Wen, L.-P. and Fulco, A.J. (1989) J. Biol. Chem. 264, 10987-10995).

Low levels of zinc in hair and blood, pica, anorexia, and poor growth in Chinese preschool children

Zinc concentrations in plasma and hair were measured in 703 children, aged between 1 and 6 yr, and correlated with parameters of physical development. In the first group of 187 children brought to the Child Health Clinic for routine observation there was a positive correlation of hair zinc content and height for age, with an increased prevalence of low hair zinc content in children of shorter stature. A second group of 303 children in nurseries and kindergartens in Beijing exhibited a hair zinc content of 92 micrograms/g, and 34% of these had very low zinc values below 70 micrograms/g. The third group consisted of 213 children who were brought into the outpatient clinic for a variety of complaints, including pica, anorexia, and poor growth; these had significantly lower values of zinc in hair and plasma than well-nourished children and responded to zinc supplementation with improvement of growth and the disappearance of pica and anorexia. These results suggest that the diet consumed by the population studied may be marginal or inadequate in its content of available zinc.