Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma

PURPOSE

Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL).

METHODS

A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and β-carboxy-terminal crosslinked telopeptide of type 1 collagen (β-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously.

RESULTS

PPGL patients had a higher level of β-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent.

CONCLUSIONS

PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

Strictureplasty may lead to increased preference in the surgical management of Crohn's disease: a case-matched study

BACKGROUND

Resection and strictureplasty are the two surgical modalities used in the management of Crohn's disease (CD). The objective of this study was to compare morbidity and clinical recurrence between patients who underwent strictureplasty and patients who underwent resection.

METHODS

Patients with CD who underwent strictureplasty between January 2012 and December 2022 were enrolled. The patients were well matched with patients who underwent resection without strictureplasty. Patient- and disease-specific characteristics, postoperative morbidity, and clinical recurrence were also analyzed.

RESULTS

A total of 118 patients who underwent a total of 192 strictureplasties were well matched to 118 patients who underwent resection. The strictureplasty group exhibited significantly less blood loss (30 ml versus 50 ml, p < 0.001) and stoma creation (2.5% versus 16.9%, p < 0.001). No significant difference was found regarding postoperative complications or length of postoperative stay. At the end of the follow-up, the overall rate of clinical recurrence was 39.4%, and no difference was observed between the two groups. Postoperative prophylactic use of biologics (odds ratio = 0.2, p < 0.001) was the only protective factor against recurrence.

CONCLUSION

Strictureplasty does not increase the risk of complications or recurrence compared with resection. It represents a viable alternative to resection in selected patients, and as such, it should have a broader scope of indications and greater acceptance among surgeons.

[Study on risk factors of mycobacterium tuberculosis infection among health workers in medical institutions]

Objective: To understand the infection status of mycobacterium tuberculosis among health workers in tuberculosis designated medical institutions and explore the risk factors of infection. Methods: From September 2021 to June 2022, a questionnaire survey was conducted among health workers in relevant departments of 4 tuberculosis designated medical institutions by cluster stratified sampling, including the implementation of hospital infection control measures in medical institutions and occupational exposure of medical staff to mycobacterium tuberculosis. Peripheral blood interferon gamma release assays (IGRAs) and lung imaging examination were performed to determine the mycobacterium tuberculosis infection. Factors with statistical significance in univariate analysis were included in multivariate logistic regression to analyze the risk factors of mycobacterium tuberculosis infection. Results: A total of 657 people completed the lung imaging examination and questionnaire, of which 654 people had peripheral blood IGRAs detection, and the latent infection rate of tuberculosis was 39.45% (258/654) . Univariate analysis showed that age, sex, marital status, economic income, occupational category, professional title, length of service, and other variables had statistical significances in tuberculosis latent infection (P<0.05) . In terms of personal health status, there were statistically significant differences in the distribution of health workers in terms of their tuberculosis history, tuberculosis history of their immediate family members, previous tuberculin skin test (TST) (P<0.05) . Multivariate analysis showed that there were four risk factors related to tuberculosis, including professional title (X(1)) , years of tuberculosis related works (X(2)) , tuberculosis history (X(3)) and previous TST (X(4)) . The regression equation of the probability of tuberculosis among health workers was y=-1.920+0.246X(1)+0.046X(2)+1.231X(3)+0.478X(4). Conclusion: The latent infection rate of tuberculosis among health workers in tuberculosis designated medical institutions is high. It is necessary to strengthen the management of infection control, carry out regular screening, enhance the self-protection awareness of health workers, and reduce their exposure to mycobacterium tuberculosis and infection risk.

Mutational antigenic landscape of prevailing H9N2 influenza virus hemagglutinin spectrum

H9N2 influenza viruses are globally endemic in birds, and a sharp increase in human infections with H9N2 occurred during 2021 to 2022. In this study, we assess the antigenic and pathogenic impact of 23 hemagglutinin (HA) amino acid mutations. Our study reveals that three specific mutations, labeled R164Q, N166D, and I220T, are responsible for the binding of antibodies with escape mutations. Variants containing R164Q and I220T mutations increase viral replication in avian and mammalian cells. Furthermore, T150A and I220T mutations are found to enhance viral replication in mice, indicating that these mutations may have the potential to adapt mammals. Structure analysis reveals that residues 164 and 220 bearing R164Q and I220T mutations increase interactions with the surrounding residues. Our findings enrich current knowledge about the risk assessment regarding which predominant HA immune-escape mutations of H9N2 viruses may pose the greatest threat to the emergence of pandemics in birds and humans.

Prediction of Response to Neoadjuvant Chemoradiotherapy Combined with Pembrolizumab in Esophageal Squamous Cell Carcinoma with CT/FDG PET Radiomic Signatures Based on Machine Learning Classification

PURPOSE/OBJECTIVE(S)

PALACE-1 trial has confirm that the addition of pembrolizumab to neoadjuvant chemoradiotherapy (NCRT) improves the pathological complete response(pCR) for esophageal squamous cell carcinoma (ESCC), which might be a novel treatment strategy for ESCC. In the present study, we aim to establish a machine learning model to predict the local response to NCRT+ pembrolizumab for ESCC by using pretreatment 18-fluorodeoxyglucose positron emission tomography (FDG PET) and contrast-enhanced plan CT images.

MATERIALS/METHODS

A total of 65 cases treated with NCRT+ pembrolizumab followed by surgery were prospectively enrolled for analysis from 2019-2022. Each patient contains a contrast-enhanced plan CT and FDG PET images. 52 patients were randomly divided into training set and 13 patients were used as test set. The Extraction of radiomics features was performed using an open-source Python library PyRadiomics automatically. Features were computed according to the radiologist-drawn ROIs on both CT and PET images. In the feature selection stage least absolute shrinkage and selection operator (LASSO) was utilized on CT features and PET features separately. Four different machine learning models were implemented: Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF) and XGBoost (XGB). The features selected by LASSO regression were used as model input and the output of the model is "pCR" or "non-pCR". To find the optimal parameter, the 5-fold cross-validation method was used in the training stage. In this study, we use accuracy, sensitivity and specificity as the metrics to evaluate the performance of the model on the testing cohort. The predictive performance of the model was assessed using the area under curve (AUC) of the receiver operating characteristics curve (ROC).

RESULTS

Of the 65 cases treated with NCRT+pembrolizumab, 35 patients archived pCR (53.8%), and 30 archived non-pCR. 1684 radiomics features were extracted from each case, and half of them (842 features) were from CT and others were from PET. Among the machine learning models mentioned above SVM achieves the most promising performance on the evaluation metrics. Accuracy, sensitivity, specificity and AUC score on test set were 0.692, 0.833, 0.571 and 0.786 for CT features and 0.615, 0.667, 0.571 and 0.762 for PET features, respectively. For CT+FDG PET fused features accuracy, sensitivity, specificity and AUC score on test set were 0.769, 0.667, 0.857 and 0.833.

CONCLUSION

In this study, we performed several different machine learning models to predict the response to NCRT+ pembrolizumab among ESCC based on the extracted radiomics features from CT and FDG PET images. The best-performing model based on radiomics features of CT and PET images could identify non-pCR to NCRT + pembrolizumab in EC patients.

Treatment Outcomes of Concurrent Nimotuzumab with Intensity Modulated Radiotherapy in Advanced Nasopharyngeal Carcinoma Patients Unfit for Concurrent Chemoradiotherapy: A Single Institute Experience

PURPOSE/OBJECTIVE(S)

To assess the safety and efficacy of intensity-modulated radiotherapy (IMRT) combined with nimotuzumab for patients with locally advanced nasopharyngeal carcinoma (LA-NPC) medically unfit to receive concomitant chemotherapy.

MATERIALS/METHODS

From 2016.6 to 2020.9, 34 newly diagnosed patients with local-regional advanced NPC medically unfit for concurrent chemoradiation had undergone definitive radiotherapy and were retrospectively evaluated. All patients were treated with IMRT combined treatment modality of nimotuzumab with or without cisplatin-based induction chemotherapy. Nimotuzumab was administered concurrently with IMRT at a weekly dose of 200 mg. Acute and late radiation-related toxicities were evaluated based on the Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 during and after IMRT. The Kaplan-Meier method was used for survival analysis. Univariate and multivariate prognostic analyses were performed by using the Cox proportional hazard model.

RESULTS

The median follow-up time for the entire group was 15 months (range 5 to 55 months). At the time of this analysis, a total of 2 cases developed loco-regional recurrence. In addition, 4 patients developed distant metastasis. There was a total of 5 deaths: 3 patients died from distant metastasis, 1 patient died from the progression of loco-regional disease after recurrence, and the causes of death for the additional 1 case was a nasopharyngeal ulcer and deadly bleeding. The 1-year OS rate of the whole cohort was 87.9%, and the 1-year LFFR, DFFR, and PFS rates were 100%, 91.0%, and 91.0%, respectively. During the period of concurrent nimotuzumab and IMRT, no grade 3-4 hematologic toxicities and dermatitis were observed. Grade 3-4 radiotherapy-related oral mucositis was reported in 7 patients (20.6%). No infusion reaction was observed. No acneiform eruptions were found among these patients. The most commonly observed late complication was xerostomia. The degree of dry mouth in most patients was mild-to-moderate at the time of the last follow-up. Finally, 7 patients developed either unilateral or bilateral hearing impairment. One female patient experienced a nasopharyngeal ulcer and deadly bleeding after 5 months of completion of radiotherapy.

CONCLUSION

Concurrent nimotuzumab with IMRT for the treatment of LA-NPC was well tolerated, with encouraging survival data, and it could be an effective treatment alternative for patients with LA-NPC medically unfit for concomitant chemotherapy. Further clinical trials are needed to confirm these findings.

Development of a novel combined nomogram integrating deep-learning-assisted CT texture and clinical-radiological features to predict the invasiveness of clinical stage IA part-solid lung adenocarcinoma: a multicentre study

AIM

To develop a novel combined nomogram based on deep-learning-assisted computed tomography (CT) texture (DL-TA) and clinical-radiological features for the preoperative prediction of invasiveness in patients with clinical stage IA lung adenocarcinoma manifesting as part-solid nodules (PSNs).

MATERIALS AND METHODS

This study was conducted from January 2015 to October 2021 at three centres: 355 patients with 355 PSN lung adenocarcinomas who underwent surgical resection were included and classified into the training (n=222) and validation (n=133) cohorts. PSN segmentation on CT images was performed automatically with a commercial deep-learning algorithm, and CT texture features were extracted. The least absolute shrinkage and selection operator was used for feature selection and transformed into a DL-TA score. The combined nomogram that incorporated the DL-TA score and identified clinical-radiological features was developed for the prediction of pathological invasiveness of the PSNs and validated in terms of discrimination and calibration.

RESULTS

The present study generated a combined nomogram for predicting the invasiveness of PSNs that included age, consolidation-to-tumour ratio, smoking status, and DL-TA score, with a C-index of 0.851 (95% confidence interval: 0.826-0.877) for the training cohort and 0.854 (95% confidence interval: 0.817-0.891) for the validation cohort, indicating good discrimination. Furthermore, the model had a Brier score of 0.153 for the training cohort and 0.135 for the validation cohort, indicating good calibration.

CONCLUSION

The developed combined nomogram consisting of the DL-TA score and clinical-radiological features and has the potential to predict the individual risk for the invasiveness of stage IA PSN lung adenocarcinomas.

Establishing a Risk Stratification Model to Identify Clinically High-Risk N0 Breast Cancer Who Could Benefit from Regional Nodal Irradiation: A Single Institute Analysis

PURPOSE/OBJECTIVE(S)

The adverse clinical features for pN0 BC patients significantly varies and there is no established clinical risk stratification system to identify those "high-risk" pN0 BC patients who might benefit from RNI. The purpose of this real-world study was to investigate the risk factors for developing recurrence among patients with pathological T1-3N0 breast cancer (BC) treated with breast-conserving surgery (BCS) followed by whole breast irradiation alone (WBI) and identify those clinically high-risk BCs who could benefit from regional nodal irradiation (RNI).

MATERIALS/METHODS

Female BC patients treated from 2009 to 2016 were retrospectively reviewed. The disease-free survival (DFS) and overall survival (OS) were estimated by the Kaplan-Meier method, and survival differences were compared with the log-rank test. Univariate and multivariate analysis was performed using Cox logistic regression analysis. An external validation was conducted by using SEER database.

RESULTS

A total of 622 BC patients treated with BCS+WBI alone were included. With a median follow-up of 82 months, the 7-year OS and DFS for the entire cohort was 97% and 91%, respectively. Multivariable Cox analysis indicated that tumor size (p = 0.006), tumor location (p = 0.033), lymphovascular invasion (LVI) status (p = 0.0028) and Ki-67 index (p = 0.051) were independent risk factors for DFS, while only tumor size was the only independent risk factors for OS (p = 0.029). A scoring system was developed using these four factors and the 7-year DFS and OS were 97% and 96% for patients with 0-1 risk factors, 95% and 82% for patients with ≥2 risk factors (p<0.0001 for DFS, and p = 0.0063 for OS). Based on tumor size and tumor location, an external validation by demonstrated that the 7-year OS was 90% and 88% for patients with 0-1 risk factor, which was significantly better than those defined as high-risk BC patients (82%, p<0.0001).

CONCLUSION

By using our institute database, we establish a risk stratification system for identifying sub-group of pN0 BC patients, who are at high risk for developing recurrence. The results of our study support tailored RT decision-making according to individual risks, which needed to be confirmed in further studies.

The Safety and Efficacy of SCART for Bulky Metastatic or Recurrent Cancer, a Phase I Study

PURPOSE/OBJECTIVE(S)

We are proposing a new treatment methodology, (called Stereotactic Centralized Ablative Radiation Therapy, (SCART), for bulky or metastatic tumors, which is based on the principles of SFRT, by using SBRT methods to deliver an ablative radiation dose to the central portion of the target while keeping the dose to surrounding normal tissue to a relatively low level. We performed a prospective dose escalation study of SCART for bulky metastatic or recurrent cancer. The purpose of the study was to determine dose-limiting toxicities (DLTs) and the Maximum Tolerated Dose (MTD) of SCART.

MATERIALS/METHODS

This study was registered at ClinicalTrials.gov Identifier: NCT0488198, and approved at Foshan Chancheng Hospital. Patients with unresectable solid "bulky" nonhematological malignancies with limited treatment options were enrolled and received SCART with a prescription to the central spot in the tumor with a peripheral dose to the tumor edge at around 20% isodose line of the prescription dose. Five dose levels were proposed. The primary endpoint was the maximum tolerated dose (MTD), defined as the highest dose where zero of three or one of six patients experienced grade 3 dose-limiting toxicity (DLT), scored according to the Common Toxicity Criteria for Adverse Events v. 4.03, up to 6 months after SCART.

RESULTS

A total of 21 patients received SCART and have eligible data for study follow-up. The dose was escalated for two patients to 24 GyX3. No grade 3 toxicity was observed in any of the enrolled patients. The median SCART dose was 18 Gy (range: 15 - 24). Six out of the 18 patients with data for overall survival (OS) died, and the median time to death was 16.29 months (range: 0.99 - 25.58). Three patients out of the 15 patients with available data for local recurrence (LR) were found to have an LR and the median time to LR was 16.01 months (range: 0.99 - 25.58). There appears to be a trend of tumors decreasing from the patient's first visit date, or pre-SCART, to their final volume post-SCART. The mean percent change for tumor shrinkage between first visit volumes and post-SCART volumes was 49.49% (SD: 40.89, p-value:0.009). Of 15 patients with available data for progression free survival, 9 had a local recurrence or were deceased. Estimated median survival (i.e., when survival is 50%) was equal to16.80 months (95% CI = 13.90, NA). The survival rate at 12 months and 24 months were72.22% and 24.07%, respectively. Of 15 patients with available data for time to local recurrence, 3 people had a local recurrence. The percent of patients that were free from local recurrence at one and two years after the beginning of SCART treatment was 85.56% for both.

CONCLUSION

Despite the high dose delivered and the excellent local control achieved; the incidence of Any toxicity was unexpectedly low. Multiple courses of SCART are possible. The optimal dose, volume and timing of SCART still need more study.

Nodal Response to Neo-Adjuvant Systemic Therapy Predicts Prognosis of cN3c Breast Cancer Patients Receiving Multidisciplinary Therapy

PURPOSE/OBJECTIVE(S)

cN3c breast cancer with ipsilateral supraclavicular (SCV) lymph nodal (SCLN) metastasis has a dismal prognosis. We investigated the survival outcomes, patterns and risks of recurrence in those patients after multidisciplinary therapy, as well as the predictors of candidates for SCV area boosting.

MATERIALS/METHODS

Consecutive cN3c breast cancer patients without distant metastases from January 2009 to December 2020 in our institution were retrospectively reviewed. Based on nodal response to neoadjuvant therapy (NAT), patients were categorized into three groups: clinical complete response (cCR) not achieved in SCLN (Group A, n = 66), SCLN cCR but axillary node (ALN) did not achieve pathological complete response (pCR, Group B, n = 34), cCR in SCLN and pCR in ALN (Group C, n = 13).

RESULTS

The median follow-up time was 32.7 months (range, 21.9-53.3months). The 5-year overall survival (OS) and recurrence-free survival (RFS) rates were 64.6% and 43.7% respectively. Multivariate analysis showed cumulative SCV dose and ypT stage, ALN response and SCV response to NAT were significantly associated with OS and RFS respectively. The 3-year for patients receiving the cumulative SCV dose of ≥60 Gy versus <60 Gy was 81.3% versus 69.0% (P = 0.042). Compared with Group A or B, Group C showed significantly improved RFS (3y-RFS: 53.8% vs 73.6% vs 100%, p = 0.003) and a numerically longer OS (3y-OS: 73.4% vs 86.7% vs 100%, p = 0.089). Meanwhile, Group C showed the lowest rate of DM as first failure (37.9 % vs 23.5% vs 0 in group A, B and C, respectively, p = 0.010). In patients of Group A, the 3-year OS rates for patients receiving the cumulative SCV dose of ≥60 Gy versus <60 Gy was 78.0% versus 57.3% (p = 0.029).

CONCLUSION

Nodal response to NAT is an independent prognostic factor for survival and pattern of failure. cN3c breast cancer patients with SCLN cCR and ALN pCR after NAT are potentially curable. A cumulative SCV dose of ≥60 Gy is positively associated with improved OS, especially in patients of SCLN without achieving cCR. Our data supports the perspective of optimizing radiotherapeutic strategy based on nodal response.

High-Flux Neutron Generator Based on Laser-Driven Collisionless Shock Acceleration

A novel compact high-flux neutron generator with a pitcher-catcher configuration based on laser-driven collisionless shock acceleration (CSA) is proposed and experimentally verified. Different from those that previously relied on target normal sheath acceleration (TNSA), CSA in nature favors not only acceleration of deuterons (instead of hydrogen contaminants) but also increasing of the number of deuterons in the high-energy range, therefore having great advantages for production of high-flux neutron source. The proof-of-principle experiment has observed a typical CSA plateau feature from 2 to 6 MeV in deuteron energy spectrum and measured a forward neutron flux with yield 6.6×10^{7}  n/sr from the LiF catcher target, an order of magnitude higher than the compared TNSA case, where the laser intensity is 10^{19}  W/cm^{2}. Self-consistent simulations have reproduced the experimental results and predicted that a high-flux forward neutron source with yield up to 5×10^{10}  n/sr can be obtained when laser intensity increases to 10^{21}  W/cm^{2} under the same laser energy.

USP1-Associated Factor 1 Modulates Japanese Encephalitis Virus Replication by Governing Autophagy and Interferon-Stimulated Genes

Japanese encephalitis virus (JEV) is a typical mosquito-borne flavivirus that can cause central nervous system diseases in humans and animals. Host factors attempt to limit virus replication when the viruses invade the host by using various strategies for replication. It is essential to clarify the host factors that affect the life cycle of JEV and explore its underlying mechanism. Here, we found that USP1-associated factor 1 (UAF1; also known as WD repeat-containing protein 48) modulated JEV replication. We found that JEV propagation significantly increased in UAF1-depleted Huh7 cells. Moreover, we found that knockdown of UAF1 activated cell autophagic flux in further functional analysis. Subsequently, we demonstrated that autophagy can be induced by JEV, which promotes viral replication by inhibiting interferon-stimulated gene (ISG) expression in Huh7 cells. The knockdown of UAF1 reduced ISG expression during JEV infection. To explore the possible roles of autophagy in UAF1-mediated inhibition of JEV propagation, we knocked out ATG7 to generate autophagy-deficient cells and found that depletion of UAF1 failed to promote JEV replication in ATG7 knockout cells. Moreover, in ATG7-deficient Huh7 cells, interference with UAF1 expression did not lead to the induction of autophagy. Taken together, these findings indicate that UAF1 is a critical regulator of autophagy and reveal a mechanism by which UAF1 knockdown activates autophagy to promote JEV replication. IMPORTANCE Host factors play an essential role in virus replication and pathogenesis. Although UAF1 is well known to form complexes with ubiquitin-specific proteases, little is known about the function of the UAF1 protein itself. In this study, we confirmed that UAF1 is involved in JEV replication. Notably, we discovered a novel function for UAF1 in regulating autophagy. Furthermore, we demonstrated that UAF1 modulated JEV replication through its autophagy regulation. This study is the first description of the novel function of UAF1 in regulating autophagy, and it clarifies the underlying mechanism of the antiviral effect of UAF1 against JEV. These results provide a new mechanistic insight into the functional annotation of UAF1 and provide a potential target for increasing virus production during vaccine production.

[The design method of the digital sequential tooth-sectioning guide for the extraction of mandibular impacted third molars]

Objective: To explore a method for digitally designing and fabricating a sequential tooth-sectioning guide that can assist in the extraction of mandibular horizontal impacted third molars, preliminarily evaluate its feasibility and provide a reference for clinical application. Methods: Twenty patients with mandibular low level impacted third molars who visited the Department of General Dentistry, Peking University School and Hospital of Stomatology from March 2021 to January 2022 were selected. Cone-beam CT showed direct contact between the roots and mandibular canal, and full range impressions of the patients' intraoral teeth were taken and optical scans of the dental model were performed. The patients' cone-beam CT data and optical scan data were reconstructed in three dimensions, anatomical structure extraction, registration fusion, and the design of the structure of the guide (including crown-sectioning guide and root-sectioning guide) by Mimics 24.0, Geomagic Wrap 2021, and Magics 21.0 software, and then the titanium guide was three dimension printed, and the guide was tried on the dental model. After confirmation, the guide was used to assist the dentist in the operation. We observed whether the guide was in place, the number of tooth splitting, the matching of tooth splitting with the preoperative design, the operation time, and whether there were any complications. Results: In this study, 20 sectioning guides were successfully printed, all of them were well fitted in the patients' mouth, the average number of section was 3.4 times, the tooth parts was better matched with the preoperative design, and the average operative time of the guides was (29.2±9.8) minutes without complications such as perforation of the bone cortex. Conclusions: The use of sequential sectioning guides to assist in the extraction of mandibular impacted third molars was initially validated to accurately replicate the preoperative sectioning design, and is expected to provide a digital solution to improve surgical precision and ensure safety. Further studies with larger sample sizes are needed to evaluate its accuracy and safety.

Senecavirus A-induced glycolysis facilitates virus replication by promoting lactate production that attenuates the interaction between MAVS and RIG-I

Senecavirus A (SVA)-induced porcine idiopathic vesicular disease has caused huge economic losses worldwide. Glucose metabolism in the host cell is essential for SVA proliferation; however, the impact of the virus on glucose metabolism in host cells and the subsequent effects are still unknown. Here, glycolysis induced by SVA is shown to facilitate virus replication by promoting lactate production, which then attenuates the interaction between the mitochondrial antiviral-signaling protein (MAVS) and retinoic acid-inducible gene I (RIG-I). SVA induces glycolysis in PK-15 cells, as indicated by significantly increased expression of hexokinase 2 (HK2), 6-phosphofructokinase (PFKM), pyruvate kinase M (PKM), phosphoglycerate kinase 1 (PGK1), hypoxia-inducible factor-1 alpha (HIF-1α), and superoxide dismutase-2 (SOD2) in a dose-and replication-dependent manner, and enhanced lactate production, while reducing ATP generation. Overexpression of PKM, PGK1, HIF-1α, and PDK3 in PK-15 cells and high glucose concentrations promote SVA replication, while glycolytic inhibitors decrease it. Inhibition of RLR signaling allowed better replication of SVA by promoting lactate production to attenuate the interaction between MAVS and RIG-I, and regulatory effect of glycolysis on replication of SVA was mainly via RIG-I signaling. SVA infection in mice increased expression of PKM and PGK1 in tissues and serum yields of lactate. Mice treated with high glucose and administered sodium lactate showed elevated lactate levels and better SVA replication, as well as suppressed induction of RIG-I, interferon beta (IFNβ), IFNα, interferon-stimulated gene 15 (ISG15), and interleukin 6 (IL-6). The inhibitory effect on interferons was lower in mice administered sodium oxamate and low glucose compared to the high glucose, indicating that RLR signaling was inhibited by SVA infection through lactate in vitro and in vivo. These results provide a new perspective on the relationship between metabolism and innate immunity of the host in SVA infection, suggesting that glycolysis or lactate may be new targets against the virus.

Highly efficient and robust π-FISH rainbow for multiplexed in situ detection of diverse biomolecules

In the unprecedented single-cell sequencing and spatial multiomics era of biology, fluorescence in situ hybridization (FISH) technologies with higher sensitivity and robustness, especially for detecting short RNAs and other biomolecules, are greatly desired. Here, we develop the robust multiplex π-FISH rainbow method to detect diverse biomolecules (DNA, RNA, proteins, and neurotransmitters) individually or simultaneously with high efficiency. This versatile method is successfully applied to detect gene expression in different species, from microorganisms to plants and animals. Furthermore, we delineate the landscape of diverse neuron subclusters by decoding the spatial distribution of 21 marker genes via only two rounds of hybridization. Significantly, we combine π-FISH rainbow with hybridization chain reaction to develop π-FISH+ technology for short nucleic acid fragments, such as microRNA and prostate cancer anti-androgen therapy-resistant marker ARV7 splicing variant in circulating tumour cells from patients. Our study provides a robust biomolecule in situ detection technology for spatial multiomics investigation and clinical diagnosis.

That H9N2 avian influenza viruses circulating in different regions gather in the same live-poultry market poses a potential threat to public health

H9N2 avian influenza viruses are endemic and persistent in China, but those that are prevalent in different provinces are also causes of wide epidemics, related to the spread of wild birds and the cross-regional trade in live poultry. For the past 4 years, beginning in 2018, we have sampled a live-poultry market in Foshan, Guangdong, in this ongoing study. In addition to the prevalence of H9N2 avian influenza viruses in China during this period, we identified isolates from the same market belonging to clade A and clade B, which diverged in 2012-2013, and clade C, which diverged in 2014-2016, respectively. An analysis of population dynamics revealed that, after a critical divergence period from 2014 to 2016, the genetic diversity of H9N2 viruses peaked in 2017. Our spatiotemporal dynamics analysis found that clade A, B, and C, which maintain high rates of evolution, have different prevalence ranges and transmission paths. Clades A and B were mainly prevalent in East China in the early stage, and then spread to Southern China, becoming epidemic with clade C. Strains from different regions converge at the same live-poultry market to communicate, which may be one reasons the H9N2 viruses are difficult to eradicate and increasingly dominant throughout China. Selection pressure and molecular analysis have demonstrated that single amino acid polymorphisms at key receptor binding sites 156, 160, and 190 under positive selection pressure, suggesting that H9N2 viruses are undergoing mutations to adapt to new hosts. Live-poultry markets are important because people who visit them have frequent contact with poultry, H9N2 viruses from different regions converge at these markets and spread through contact between live birds and humans, generating increased risks of human exposure to these viruses and threatening public health safety. Thus, it is important to reducing the cross-regional trade of live poultry and strengthening the monitoring of avian influenza viruses in live-poultry markets to reduce the spread of avian influenza viruses.

N6-methyladenosine modification of viral RNA and its role during the recognition process of RIG-I-like receptors

N⁶-methyladenosine (m⁶A) is the most abundant RNA chemical modification in eukaryotes and is also found in the RNAs of many viruses. In recent years, m⁶A RNA modification has been reported to have a role not only in the replication of numerous viruses but also in the innate immune escape process. In this review, we describe the viruses that contain m⁶A in their genomes or messenger RNAs (mRNAs), and summarize the effects of m⁶A on the replication of different viruses. We also discuss how m⁶A modification helps viral RNAs escape recognition by exogenous RNA sensors, such as retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), during viral invasion. Overall, the goal of our review is to summarize how m⁶A regulates viral replication and facilitates innate immune escape. Furthermore, we elaborate on the potential of m⁶A as a novel antiviral target.

A Characterization and an Evolutionary and a Pathogenicity Analysis of Reassortment H3N2 Avian Influenza Virus in South China in 2019-2020

Seasonal H3N2 influenza virus has always been a potential threat to public health. The reassortment of the human and avian H3N2 influenza viruses has resulted in major influenza outbreaks, which have seriously damaged human life and health. To assess the possible threat of the H3N2 avian influenza virus to human health, we performed whole-genome sequencing and genetic evolution analyses on 10 H3N2 field strains isolated from different hosts and regions in 2019-2020 and selected representative strains for pathogenicity tests on mice. According to the results, the internal gene cassettes of nine strains had not only undergone reassortment with the H1, H2, H4, H6, and H7 subtypes, which circulate in poultry and mammals, but also with H10N8, which circulates in wild birds in the natural environment. Three reassorted strains were found to be pathogenic to mice, of these one strain harboring MP from H10N8 showed a stronger virulence in mice. This study indicates that reassorted H3N2 AIVs may cross the host barrier to infect mammals and humans, thereby, necessitating persistent surveillance of H3N2 AIVs.

Toosendanin suppresses African swine fever virus replication through upregulating interferon regulatory factor 1 in porcine alveolar macrophage cultures

African swine fever virus (ASFV) is a highly infectious and lethal swine pathogen that causes severe socio-economic consequences in affected countries. Unfortunately, effective vaccine for combating ASF is unavailable so far, and the prevention and control strategies for ASFV are still very limited. Toosendanin (TSN), a triterpenoid saponin extracted from the medicinal herb Melia toosendan Sieb. Et Zucc, has been demonstrated to possess analgesic, anti-inflammatory, anti-botulism and anti-microbial activities, and was used clinically as an anthelmintic, while the antiviral effect of TSN on ASFV has not been reported. In this study, we revealed that TSN exhibited a potent inhibitory effect on ASFV GZ201801-38 strain in porcine alveolar macrophages (PAMs; EC₅₀ = 0.085 μM, SI = 365) in a dose-dependent manner. TSN showed robust antiviral activity in different doses of ASFV infection and reduced the transcription and translation levels of ASFV p30 protein, viral genomic DNA quantity as well as viral titer at 24 and 48 h post-infection. In addition, TSN did not affect virion attachment and release but intervened in its internalization in PAMs. Further investigations disclosed that TSN played its antiviral role by upregulating the host IFN-stimulated gene (ISG) IRF1 rather than by directly inactivating the virus particles. Overall, our results suggest that TSN is an effective antiviral agent against ASFV replication in vitro and may have the potential for clinical use.

Identification of cytochrome c oxidase subunit 4 isoform 1 as a positive regulator of influenza virus replication

Human infection with highly pathogenic H5N1 influenza virus causes severe respiratory diseases. Currently, the drugs against H5N1 are limited to virus-targeted inhibitors. However, drug resistance caused by these inhibitors is becoming a serious threat to global public health. An alternative strategy to reduce the resistance risk is to develop antiviral drugs targeting host cell proteins. In this study, we demonstrated that cytochrome c oxidase subunit 4 isoform 1 (COX41) of host cell plays an important role in H5N1 infection. Overexpression of COX41 promoted viral replication, which was inhibited by silencing or knockout the expression of COX41 in the host cell. The ribonucleoproteins (RNPs) of H5N1 were retained in the cell nucleus after knockout cellular COX41. Strikingly, inhibition of cellular COX41 by lycorine, a small-molecule compound isolated from Amaryllidaceae plants, reduced the levels of COX41-induced ROS and phosphorylation of extracellular signal-regulated kinase (ERK) in cells, thus resulting in the blockage of nuclear export of vRNP and inhibition of viral replication. In H5N1-infected mice that were treated with lycorine, we observed a reduction of viral titers and inhibition of pathological changes in the lung and trachea tissues. Importantly, no resistant virus was generated after culturing the virus with the continuous treatment of lycorine. Collectively, these findings suggest that COX41 is a positive regulator of H5N1 replication and might serve as an alternative target for anti-influenza drug development.

The PB2 co-adaptation of H10N8 avian influenza virus increases the pathogenicity to chickens and mice

Avian influenza (AI) is an important zoonotic disease, which can be transmitted across species barriers to other hosts, especially humans, posing a serious threat to the poultry industry and public health. In recent years, human cases infected with the H10N8, H9N2, and H7N9 of avian influenza viruses (AIVs) have been identified frequently as have the internal genes of H7N9 and H10N8, which are derived from H9N2 viruses. The adaptive mutation of the PB2 gene is an important way for the H10N8, H9N2, and H7N9 AIVs to spread across species to adapt to new hosts. Several well-known adaptive mutations in the PB2 gene, such as E627K, D701N, and A588V, significantly enhanced the virulence of the AIVs in mammals. However, the co-adaptation of AIVs to avian and mammalian hosts is rarely studied. In this study, we found that the mutations of PB2-I292V, PB2-R389K, PB2-A588V, PB2-T598M/V, PB2-L648V, and PB2-T676M substitutions significantly increased after 2012. In addition, in our previous studies, we found that the human-origin and avian-origin of H10N8 AIVs with very high homology also have these six mutation differences in PB2 gene, and the avian-origin H10N8 strain known as JX102 with all the key amino acids on the PB2 protein in the pre-evolutionary stage, so JX102 was chosen as a model strain. Among them, PB2-A588V significantly enhanced the activity of polymerase in avian and mammalian cells. Notably, animal experiments showed that PB2-A588V substitution increased the pathogenicity and transmissibility in chickens and the virulence of mice. The combined mutations of PB2-F6 (including PB2-I292V, PB2-R389K, PB2-A588V, PB2-T598M, PB2-L648V, and PB2-T676M) obtained higher adaptability of AIVs in avians and mammals than that of the single mutation of PB2-A588V, which suggested that the PB2 588 site is a key co-adaptation site and that synergies with other mutation sites can further enhance this co-adaptability. The results of this study show that the emergence of co-adaptation not only increases the threat to avians and mammals but may also contribute to a pandemic among avians and cross the interspecies barrier to mammals.

Development and Application of a Duplex Droplet Digital Polymerase Chain Reaction Assay for Detection and Differentiation of EP402R-Deleted and Wild-Type African Swine Fever Virus

African swine fever (ASF) is a highly fatal porcine disease caused by the African swine fever virus (ASFV), and resulting in huge economic losses across the globe. ASF has been raging in China for 3 years, and recently EP402R-deleted ASFV strains emerged, showing sub-acute or chronic symptoms in pigs and providing novel difficulties to monitor and control the disease as EP402R-deleted strains possess no hemadsorption (HAD) ability. In addition, the gene deletion virus with low viral load is prone to results retest or false negative due to the high cycle threshold (Ct) value under the current real-time polymerase chain reaction (PCR) detection method. Thus, a new method is needed to detect and distinguish wild strains and gene-deleted viruses. In this study, a duplex droplet digital polymerase chain reaction (ddPCR) assay based on the ASFV B646L and EP402R genes was established and showed good linearity (R² > 0.99). The limit of detection for duplex ddPCR was 52 copies per reaction and 8.6 copies per reaction for B646L and EP402R, respectively. No cross-reaction with other porcine viruses [classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV), porcine parvovirus (PPV), Japanese encephalitis virus (JEV), and porcine circovirus type 2 (PCV2)] was identified by this assay. In addition, 44 ASFV-suspicious clinical samples as well as EP402R-deleted ASFV were tested in parallel by duplex real-time PCR and ddPCR, indicative of a higher sensitivity which belonged to the duplex ddPCR assay. In summary, this is the first time that duplex ddPCR assay has been successfully developed to provide an efficient method to detect and differentiate ASFV wild-type and gene-deleted strains.

POS0749 ANTI-Β2GPI-DOMAIN 1 ANTIBODIES STRATIFY HIGH RISK OF EXTRA-CRITERIA MANIFESTATIONS IN A LARGE PROSPECTIVE CHINESE COHORT OF ANTIPHOSPHOLIPID SYNDROME

Background

Anti-β2GPI-Domain 1 (β2GPI-D1) antibodies are potentially pathogenic in patients with antiphospholipid syndrome (APS), but their clinical associations and diagnostic value were unclear.

Objectives

To evaluate the clinical characteristics of APS patients with anti-β2GPI-D1 positivity, and its utility in diagnosing APS among SLE patients.

Methods

A total of 338 patients were included, of which 169 patients diagnosed with primary APS (PAPS group), 50 with APS secondary to SLE (SAPS group), 209 with SLE (SLE group). Serum anti-β2GPI-D1 IgG was measured using chemiluminescent immunoassay (Inova Company). Extra-criteria manifestations were analyzed, including thrombocytopenia, autoimmune hemolytic anemia, valvular lesions, APS nephropathy, and non-vascular neurological manifestations.

Results

Similar presence of anti-β2GPI-D1 IgG was seen among PAPS (32.80%) and SAPS (32.0%) patients, and 96.4% of those with positive anti-β2GPI-D1 IgG showed triple aPLs positivity. Anti-β2GPI-D1 IgG was significantly associated with recurrent thrombosis before APS diagnosis, microscopic thrombosis (p<0.05), but not with adverse pregnancy events (Figure 1). Notably, patients with extra-criteria manifestations, especially thrombocytopenia and APS nephropathy, showed significantly higher titers in anti-β2GPI-D1 IgG (p<0.05). After a median follow-up of twenty-five months, patients with anti-β2GPI-D1 IgG also showed a tendency of more extra-criteria events (3/55 vs 1/114, p=0.095), but not thrombotic events or adverse pregnancy events. Anti-β2GPI-D1 was positive among 8.13% of the SLE controls, and showed higher specificity (91.9%) in diagnosing SAPS among SLE patients as compared to classic aPLs.

Figure 1.

Conclusion

Anti-β2GPI-D1 IgG had a stronger association with extra-criteria manifestations in APS patients compared to three classic APLs, which properly indicated its pathogenic role of microangiopathy.

Disclosure of Interests

None declared

OP0145 VALIDATION OF 3 PREDICTION MODELS FOR THROMBOSIS IN ANTIPHOSPHOLIPID SYNDROME PATIENTS BASED ON A PROSPECTIVE COHORT

Background

Antiphospholipid syndrome (APS) is a rare and complicated acquired autoimmune thrombophilia characterized by arterial/venous thrombosis and/or recurrent pregnancy loss. Thrombosis is the first cause of death of APS patients. However, there has been no generally acknowledged model to predict thrombosis. Only adjusted global APS score (aGAPSS) was developed for prediction but based on a cross-sectional study1. Additionally, the predictive ability of Padua score and Caprini score has not been validated in APS patients.

Objectives

Aim to validate the ability of aGAPSS, Padua score and Caprini score to predict thrombosis in APS patients basing on a prospective cohort.

Methods

Consecutive APS patients who fulfilled the 2006 Sydney Revised Classification Criteria for APS, referred to Peking Union Medical College Hospital were included. Clinical data, aGAPSS, Padua score, and Caprini score at the time of diagnosis were collected. Patients with less than 1-year follow-up were excluded. Harrell c-index and calibration curve were used to validate the prediction models.

Results

A total of 302 patients were enrolled in this study. The mean age was 32±12 years old, and 202 (66.9%) were female (Table 1). Patients were followed up for a median of 36 months. During the follow-up period, there were 62 thrombotic events, with 40 (13.25%) venous and 22 (7.28%) arterial thrombosis. The 1-, 3-, and 5-year thrombosis risks were 8.9%, 16.9%, and 21.3% respectively (Figure 1A). The Harrell c-indexes for predicting thrombosis of aGAPSS, Padua score, and Caprini score were 0.56 (95% confidence interval [CI], 0.52-0.60), 0.58 (95% CI, 0.54-0.62), and 0.61 (95%CI, 0.57-0.65) respectively. The model predicting venous thrombosis with the best discrimination was Padua score whose Harrell c-index was 0.64 (95% CI, 0.60-0.68), and the model predicting arterial thrombosis with the best discrimination was Caprini score whose Harrell c-index was 0.62 (95%CI, 0.56-0.68). The calibration curves illustrated that the calibration for predicting thrombosis within 3 years after diagnosis of all the 3 models was poor (Figure 1B-D).

Table 1.

Demographic characteristics and clinical manifestations at baseline

N=302N=302Age, mean±SD32±12Clinical manifestationsFemale, n (%)202 (66.9)Venous thrombosis, n (%)156 (51.7)Disease duration (months), median (Q1, Q3)11.50 (3.00, 44.00)Deep venous thrombosis, n (%)112 (37.1)Secondary to SLE, n (%)73 (24.2)Pulmonary embolism, n (%)70 (23.2)Smoking history, n (%)63 (20.9)Visceral venous thrombosis, n (%)12 (4.0)Hypertension, n (%)59 (19.5)Cranial venous sinus thrombosis, n (%)13 (4.3)Hyperlipidemia, n (%)151 (50.0)Arterial thrombosis, n (%)113 (37.4)BMI, mean±SD23.96±3.89Stroke/TIA, n (%)62 (20.5)LA positive, n (%)241 (79.8)Myocardial infarction, n (%)14 (4.6)aCL positive, n (%)208 (68.9)Arterial thrombosis of lower extremities, n (%)22 (7.3)aβ2GPI positive, n (%)242 (80.1)Visceral arterial thrombosis, n (%)18 (6.0)Triple aPL positive, n (%)165 (54.6)Thrombocytopenia, n (%)118 (39.1)Obstetric manifestations, n (%)N=202Valvular lesions, n (%)24 (7.9)Pregnancy morbidity103 (51.0)Early miscarriages (<10 weeks)13 (6.4)Fetal death (>= 10 weeks)68 (33.7)Preeclampsia, eclampsia and placental dysfunction36 (17.8)Figure 1.

The Kaplan-Meier curve and the calibration curve of 3 prediction models within 3 years after diagnosis. A: The Kaplan-Meier curve of venous, arterial and both venous and arterial thrombosis. B: The calibration curves for venous thrombosis. C: The calibration curves for arterial thrombosis. D: The calibration curves for both venous and arterial thrombosis.

Conclusion

The ability of aGAPSS, Padua score and Caprini score to predict thrombosis in APS patients is relatively poor. Construction of a new prediction model specifically for APS patients is required to help with early prevention and treatment.

References

[1]Sciascia, S., et al., GAPSS: the Global Anti-Phospholipid Syndrome Score. Rheumatology (Oxford), 2013. 52(8): p. 1397-403.

Disclosure of Interests

None declared

Characterization of four novel H5N6 avian influenza viruses with the internal genes from H5N1 and H9N2 viruses and experimental challenge of chickens vaccinated with current commercially available H5 vaccines

Since 2014, highly pathogenic avian influenza H5N6 viruses have been responsible for outbreaks in poultry. In this study, four H5N6 virus strains were isolated from faecal samples of sick white ducks and dead chickens in Shandong in 2019. These H5N6 viruses were triple-reassortant viruses that have not been previously characterized. Their HA genes were derived from the H5 viruses and were closely related to the vaccine strain Re-11. Their NA genes all fell into the N6-like lineage and the internal gene were derived from H5N1 and H9N2 viruses. They all showed high pathogenicity in mice and caused lethal infection with high rates of transmission in chickens. Moreover, the SPF chickens inoculated with the currently used H5 (Re-11 and Re-12 strains)/H7 (H7-Re-2 strain) trivalent inactivated vaccines in China were completely protected from these four H5N6 viruses. Our study indicated the necessity of continued surveillance for H5 influenza A viruses and the importance of timely update of vaccine strains in poultry industry.

Real-Time Visualization of the Infection and Replication of a Mouse-Lethal Recombinant H9N2 Avian Influenza Virus

H9N2 avian influenza viruses (AIVs) continuously cross the species barrier to infect mammalians and are repeatedly transmitted to humans, posing a significant threat to public health. Importantly, some H9N2 AIVs were found to cause lethal infection in mice, but little is known about the viral infection dynamics in vivo. To analyze the real-time infection dynamics, we described the generation of a mouse-lethal recombinant H9N2 AIV, an influenza reporter virus (V_K627-NanoLuc virus) carrying a NanoLuc gene in the non-structural (NS) segment, which was available for in vivo imaging. Although attenuated for replication in MDCK cells, V_K627-NanoLuc virus showed similar pathogenicity and replicative capacity in mice to its parental virus. Bioluminescent imaging of the V_K627-NanoLuc virus permitted successive observations of viral infection and replication in infected mice, even following the viral clearance of a sublethal infection. Moreover, V_K627-NanoLuc virus was severely restricted by the K627E mutation in PB2, as infected mice showed little weight loss and a low level of bioluminescence. In summary, we have preliminarily established a visualized tool that enables real-time observation of the infection and replication dynamics of H9N2 AIV in mice, which contributes to further understanding the mechanisms underlying the pathogenic enhancement of H9N2 AIV to mice.

Prevention and Control Strategies of African Swine Fever and Progress on Pig Farm Repopulation in China

African swine fever (ASF) is a devastating disease in domestic and wild pigs. Since the first outbreak of ASF in August 2018 in China, the disease has spread throughout the country with an unprecedented speed, causing heavy losses to the pig and related industries. As a result, strategies for managing the disease are urgently needed. This paper summarizes the important aspects of three key elements about African swine fever virus (ASFV) transmission, including the sources of infection, transmission routes, and susceptible animals. It overviews the relevant prevention and control strategies, focusing on the research progress of ASFV vaccines, anti-ASFV drugs, ASFV-resistant pigs, efficient disinfection, and pig farm biosecurity. We then reviewed the key technical points concerning pig farm repopulation, which is critical to the pork industry. We hope to not only provide a theoretical basis but also practical strategies for effective dealing with the ASF epidemic and restoration of pig production.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

AIM

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma.

MATERIALS AND METHODS

A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated.

RESULTS

Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively).

CONCLUSIONS

A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

[The predictive value of ureteral wall area for impacted ureteral stones]

Objective: To investigate the clinical indicators for preoperative prediction of impacted ureteral stones and analyze the predictive value of ureteral wall area(UWA). Methods: A total of 197 patients who underwent ureteroscopic lithotripsy due to ureteral stones at our institution from January to December 2020 were retrospectively analyzed. Preoperative patient age, gender, body mass index (BMI), history of hypertension, diabetes mellitus, side of stone, location of stone, maximum diameter of stone, CT value of stone, C-reactive protein (CRP), creatinine, renal pelvis diameter, ureteral wall thickness and UWA were collected. Patients were divided into impacted and non-impacted groups according to whether the stones were impacted intraoperatively. Univariate analysis was used to compare the differences in each clinical indicator between the two groups, and multivariate logistic regression was performed to analyze the independent predictors of impacted stones for those with differences. The receiver operating characteristic (ROC) curve was used to analyze the predictive power of each independent predictor, and the Delong test was used to analyze whether the difference in the area under the curve (AUC) of each independent predictor was statistically significant. Results: All 197 patients successfully completed the operation, aged 51 (36, 56) years; 137 males and 60 females. According to the results of ureteroscopy, they were divided into 82 cases of impacted ureteral stones and 115 cases of non-impacted ureteral stones. Univariate analysis showed that there were significant differences in maximum stone diameter, stone CT value, renal pelvis diameter, ureteral wall thickness and ureteral wall area between the two groups (P<0.05); There was no significant difference in age, gender, BMI, history of hypertension, diabetes, stone side, location of stone, CRP and creatinine (P>0.05). Multivariate logistic regression analysis showed that stone CT value (P<0.01), ureteral wall thickness (P<0.001) and ureteral wall area were independent predictors of impacted ureteral stones (P<0.001). The ROC curve was used to compare the predictive efficacy of independent predictors of stone CT value, ureteral wall thickness and ureteral wall area. The area under the ureteral wall area curve was the largest (AUC = 0.901, 95%CI: 0.859-0.943, P<0.001), followed by ureteral wall thickness (AUC = 0.799, 95%CI: 0.736-0.862, P<0.001) and stone CT value (AUC = 0.700, 95%CI: 0.626-0.775, P<0.001). By Delong test, there were significant differences in AUC between ureteral wall area and stone CT value (Z=4.527, P<0.001) and ureteral wall thickness (Z=3.407, P<0.001). The best predictive value of ureteral wall area was 79.6 mm². The sensitivity and specificity of this critical value for predicting ureteral incarcerated calculi were 80.1% and 89.5%. Conclusions: The UWA, ureteral wall thickness as well as the CT value of stones were all independent predictors of impacted ureteral stones, and UWA had a better predictive value.

Japanese encephalitis virus restricts HMGB1 expression to maintain MAPK pathway activation for viral replication

Japanese encephalitis virus (JEV) is a typical insect-borne flavivirus and an important zoonotic pathogen that causes human viral encephalitis and reproductive failure in pigs. Various strategies were utilized by JEV to facilitate its replication. It is important to identify key molecules that mediate JEV infection, as well as to investigate their underlying mechanism. In this study, the critical role of high-mobility group box 1 (HMGB1), a non-histone, DNA-binding protein, was assessed in JEV propagation. Upon JEV infection, the HMGB1 mRNA and protein levels were down-regulated at late infection in Huh7 cells. JEV replication was significantly enhanced with HMGB1 knock-down by siRNA and knock-out by the CRISPR/Cas9 system, whereas JEV growth was restricted in HMGB1-over-expressed Huh7 cells. Further investigation showed that HMGB1 suppressed MAPK pathway, and demonstrated that the weakening of MAPK pathway negatively regulated JEV infection. Together, these results suggested that JEV restricted HMGB1 expression to maintain MAPK pathway activation for viral replication. Our data showed that HMGB1 played a key role in JEV infection, providing the potential for the development of a novel drug to combat JEV infection.

3'UTR SL-IV and DB1 Regions Contribute to Japanese Encephalitis Virus Replication and Pathogenicity

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus that causes fatal neurological disease in humans, is one of the most important emerging pathogens of public health significance. JEV is maintained in an enzootic cycle and causes reproductive failure in pigs. Notably, the shift in JEV genotypes is not fully protected by existing vaccines, so the development of a candidate vaccine is urgently needed. In this study, we compared pathogenicity between Japanese encephalitis virus SA14 and BJB (isolated from humans in the 1970s) strains. We found that the BJB strain was attenuated in mice and that there was no case fatality rate. The growth rate of BJB was higher than SA14 virus in BHK-21 cells. Based on the sequence alignment of the viral genome between the SA14 and BJB virus strains, some mutations at sites 248, 254, 258, and 307 were observed in the 3′ untranslated region (3′UTR). The 3′UTR of JEV plays a very important role in the viral life cycle. Furthermore, using a reverse genetic system, we conducted and rescued the parental JEV strain SA14 (T248, A254, and A258) and the mutant virus rSA14-3′UTRmut (T248C, A254G, A258G, and 307G). Through an analysis of the RNA secondary structure model of the 3′UTR, we discovered that the mutations of T248C, A254G, and A258G reduced the apiculus ring and increased the lateral ring significantly in the stem-loop structures IV (SL-IV) structure region of 3′UTR. Moreover, the insertion of 307G added a ring to the dumbbell structure 1 (DB1) structure region. Strikingly, these RNA secondary structure changes in 3′UTR of rSA14-3′UTRmut increased viral negative chain RNA production and enhanced the replication ability of the virus in BHK-21 cells. However, in vivo mouse experiments illustrated that the rSA14-3′UTRmut virus significantly decreased the neurovirulence of JEV. These results affirmed that the JEV SL-IV and DB1 regions play an important role in viral proliferation and pathogenicity. Taken together, we complement the study of RNA element function in the 3′UTR region of JEV by providing a new target for the rational design of live attenuated candidate vaccines and the increase of virus production.

Berbamine inhibits Japanese encephalitis virus (JEV) infection by compromising TPRMLs-mediated endolysosomal trafficking of low-density lipoprotein receptor (LDLR)

Japanese encephalitis virus (JEV), a member of the Flavivirus genus, is an important pathogen that causes human and animal infectious diseases in Asia. So far, no effective antiviral agents are available to treat JEV infection. Here, we found that LDLR is a host factor required for JEV entry. Berbamine significantly decreases the level of LDLR at the plasma membrane by inducing the secretion of LDLR via extracellular vesicles (EVs), thereby inhibiting JEV infection. Mechanistically, berbamine blocks TRPMLs (Ca²⁺ permeable non-selective cation channels in endosomes and lysosomes) to compromise the endolysosomal trafficking of LDLR. This leads to the increased secretion of LDLR via EVs and the concomitant decrease in its level at the plasma membrane, thereby rendering cells resistant to JEV infection. Berbamine also protects mice from the lethal challenge of JEV. In summary, these results indicate that berbamine is an effective anti-JEV agent by preventing JEV entry.

Evolution and Antigenic Drift of Influenza A (H7N9) Viruses, China, 2017-2019

After a sharp decrease of influenza A(H7N9) virus in China in 2018, highly pathogenic H7N9 viruses re-emerged in 2019. These H7N9 variants exhibited a new predominant subclade and had been cocirculating at a low level in eastern and northeastern China. Several immune escape mutations and antigenic drift were observed in H7N9 variants.

OP0290 CLINICAL CHARACTERISTICS AND PROGNOSIS OF ANTIPHOSPHOLIPID SYNDROME PATIENTS BASED ON CLUSTER ANALYSIS: A 10-YEAR COHORT STUDY

Background:

APS is an autoimmune disease characterized by persistent antiphospholipid antibodies (aPLs) positivity, leading to thrombotic events or pregnancy morbidity. High-risk aPLs profiles included positive lupus anticoagulant (LA) and multiple aPLs positivity1. Association was also found between aPLs and a variety of manifestations beyond thrombosis, referred to “non-criteria manifestations” (i.e. thrombocytopenia, hemolytic anemia, heart valve disease and aPL-related nephropathy)2, of which the role in APS risk stratification is poorly understood. The manifestation spectrum of APS is wide, ranging from asymptomatic aPLs positivity to life-threatening catastrophic APS, and patients other than confirmed APS also need proper management. Therefore, a risk stratification integrating demographic data, aPL-related manifestations, aPLs profiles, coexisting cardiovascular risk factors and SLE is needed for management guidance and prognosis assessment.

Objectives:

Using cluster analysis, to identify phenotypes among aPL-positive patients and assess the prognosis of each phenotype.

Methods:

This is a single-center, prospective cohort study of aPL-positive patients who presented to Peking Union Medical College Hospital from 2004 to 2020. Demographic characteristics, aPL-related manifestations, cardiovascular risk factors, antibodies profile and follow-up data were recorded. The primary end point was defined as a combination of newly onset arterial thrombosis (AT) or deep venous thrombosis (DVT), major bleeding events, non-criteria manifestations and all-cause death. Hierarchical cluster analysis with the Euclidean distance and the Ward method was applied to identify clusters of patients and variables separately. Multiple comparison and Kaplan-Meier survival analysis were performed among clusters.

Results:

Four clusters among 383 patients (70.2% female; mean age 37.7 years) were identified (Figure 1A). Cluster 1 (n=138): female patients with SLE, non-criteria manifestations, triple aPLs positivity, high AT rate and moderate DVT rate. Cluster 2 (n=112): male patients with obesity, smoking history, hypertension, hyperhomocysteinemia, triple aPLs positivity and the highest rate of AT and DVT. Cluster 3 (n=83): female patients with the highest pregnancy morbidity rate and the lowest thrombosis rate. Cluster 4 (n=50): 62% male patients with isolated LA positivity, high AT rate and moderate DVT rate. Four clusters of variables were also identified (Figure 1A). From Kaplan-Meier survival analysis, 1-, 5- and 10-year event-free survival rates were 92.6%, 79.8% and 66.8%, respectively. Cluster 3 showed lowest incidence of primary endpoint (Figure 1B), while Cluster 1 and 2 showed higher newly-onset AT risk compared with other clusters (P=0.028 for 2 vs 3 and P=0.049 for 2 vs 4).

Figure 1.

Conclusion:

We identified 4 clinical phenotypes of aPL-positive patients. APS secondary to SLE was always aggregated with non-criteria manifestations. Clinicians should be alert to the possibility of SLE in aPL-positive patients with coexisting non-criteria manifestations, for whom immunosuppressive therapy besides anticoagulation may be necessary. Cluster 4 represented patients with isolated LA positivity and shared similar prognosis with secondary APS and male patients, which confirmed that LA represented a high-risk antibody spectrum. Additionally, cardiovascular risk factors (i.e. male, smoking history and obesity) played an important role in thrombosis events, and led to poor prognosis. Therefore, more attention should be paid to male patients, and the screening and management of cardiovascular risk factors should not be ignored.

References:

[1]Tektonidou MG, Andreoli L, Limper M et al. EULAR recommendations for the management of antiphospholipid syndrome in adults. Ann Rheum Dis 2019;78:1296–304.

[2]Miyakis S, Lockshin MD, Atsumi T et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost 2006;4:295–306.

Disclosure of Interests:

None declared.

POS0777 ANTIPHOSPHOLIPID RELATED LARGE VESSEL LESIONS: NOT ONLY THROMBOSIS

Background:

Antiphospholipid syndrome (APS) is demonstrated as recurrent venous/arterial thromboses or obstetric morbidities with persistent antiphospholipid antibodies(aPLs). Recently, several cases reported that non-thrombotic lesions of large vessels may exist in APS, while less report described the characteristics of these patients.

Objectives:

The study investigated patients with chronic large vessel lesions (stenosis or occlusion) (LVL) in APS, to detect the features of non-thrombotic arterial vasculopathy in APS (VAPS) by comparing with thrombotic APS (TAPS).

Methods:

This is a single-center study involved the APS database from Peking Union Medical College Hospital (PUMCH) from 2013 to 2020. The study analyzed demography and laboratory index of 18 patients with LVL by comparing with 216 patients with thrombotic APS. Patients with LVL presented no specific vasculitis or in situ thrombosis at the lesion.

Results:

Radiographic analysis in patients with LVL showed widespread thickening/enhancement of vessel wall or multiple segments stenoses, without intraluminal thrombus or atherosclerosis. In comparing with 216 patients with TAPS, the 18 patients with LVL complicated no other autoimmune diseases, had more cardiovascular risks (72.22% vs. 30.09%, P < 0.01), lower inflammatory index such as erythrocyte sedimentation rate (ESR) (6 vs. 11, p<0.05), increased cerebrovascular symptoms which maybe related to cerebral/carotid vessel occlusions (55.56%vs. 25.93%, p=0.01). Population characteristics, complications and antibody profiles in VAPS are similar to TAPS.

Conclusion:

Large vessel lesions in APS could present non-thrombotic and non-inflammatory manifestations which is different from TAPS.

Table 1.

Demographic characteristics

TAPS(n=216)VAPS(n=18)P-valueAge (years), Mean±SD39.36±13.6940.06±13.86.290Male, n (%)88(40.74)9(50.00).300SLE, n (%)53(24.54)0.008Other autoimmune diseases, n (%)4(1.85)0.724B.M.I. (kg/m2), Mean±SD24.10±4.1223.93±3.31.469Cardiovascular risk factors, n (%)65(30.09)13(72.22).001Non-criteria manifestations, n (%)109(50.46)7(38.89).243Triple positive antibodies, n (%)124(57.4)13(72.22).165Double positive antibodies, n (%)46(21.30)4(22.22).563Single positive antibody, n (%)45(20.83)1(5.56).096Arterial thrombosis, n(%)100(46.30)16(88.89).000Stroke56(25.93)10(55.56).010Venous thrombosis, n(%)152(70.37)8(44.44).025ESR (mm/h), Median (Quartile)11(5.00,29.00)6(2.75,14.00).035CRP (mg/L), Median (Quartile)1.52(0.59,4.44)1.28(0.26,1.91).054Hcy(umol/L), Median (Quartile)13.45(11.1,17.1)13.55(10.9,16.38).406

* SLE: systemic lupus erythematosus; B.M.I: Body Mass Index; Cardiovascular risks positive: patients with at least one positive of smoke, coronary heart disease, hypertension, diabetes, obesity or hyperlipidemia; Non-criteria manifestations: at least one positive of thrombocytopenia, hemolytic anemia, vulve vegetation, nephropathy, livedo reticularis, skin ulcer or non-stroke central nervous system manifestations; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; Hcy: homocysteine.

Disclosure of Interests:

None declared

POS0775 APLS-ASSOCIATED RETINAL VASCULOPATHY AS A PRESENTATION OF THROMBOTIC MICROANGIOPATHY

Background:

Persistent antiphospholipid antibodies (aPL) positivity was a recognized risk factor for thrombotic events, obstetric morbidity and a variety of manifestations beyond thrombosis. The presence of some non-criteria manifestations including thrombocytopenia, hemolytic anemia, and APS nephropathy should prompt consideration for thrombotic microangiopathy (TMA).1 Patients with APS can also present with a variety of ocular and neuro-ophthalmic manifestations, such as retinal artery/vein occlusion, retinal arteritis, optic neuritis and ischemic optic neuropathy, with underlying mechanisms remained elusive. Retinal vasculopathy including retinal artery occlusion (RAO) or retinal vein occlusion (RVO) was recently found occurred more frequently in APS patients with thrombocytopenia2, suggested other possible mechanisms besides thromboembolism.

Objectives:

To explore risk factors and possible mechanisms of retinal vasculopathy among APS patients.

Methods:

In this single-center case-control study among APS patients, we evaluated patients who fulfilled 2006 Sapporo APS Classification Criteria3 with or without retinal vasculopathy during 2018-2020 at Peking Union Medical College Hospital. Demographic data, aPL-related manifestations, cardiovascular risk factors and antibodies profile were compared and a logistical regression model was built. Hierarchical cluster analysis with the Euclidean distance and the Ward method was applied to identify clusters of variables.

Results:

A total of 310 APS patients (67.4% female, mean age 38.1 years) were included, of whom 18 patients were diagnosed with retinal vasculopathy (9 with RVO and 9 with RAO). No significant differences was found among most demographic characteristics, clinical manifestations, or antibody profile. However, APS-related heart valve disease (OR 13.66, 95% confidence interval [CI] 4.55-40.98), APS nephropathy (OR 12.77, 95% CI 4.04-40.35), thrombocytopenia (OR 2.63, 95% CI 1.01-6.89) and high serum IgM (OR 3.67, 95% CI 1.30-10.40) were predictive of retinal vasculopathy (Figure 1 A). APS-related heart valve disease and nephropathy were also found statistical significant in multivariate logistical regression (Figure 1 B). They and other non-criteria manfestations were aggregated with retinal vasculopathy from cluster analysis of variables (Figure 1 C).

Conclusion:

Patients with APS-related heart valve disease and nephropathy suffered a higher risk of retinal vasculopathy including RAO and RVO. The underlying mechanisms of aPLs-associated retinal vasculopathy may involve TMA, leading to a poor prognosis and therapeutic changes.

References:

[1]Kotzen ES, Roy S, Jain K. Antiphospholipid Syndrome Nephropathy and Other Thrombotic Microangiopathies Among Patients With Systemic Lupus Erythematosus. Adv Chronic Kidney Dis. 2019 Sep;26(5):376-386.

[2]Ermakova NA, Alekberova ZS, Reshetniak TM, Kalashnikova LA, Kosheleva NM. [Retinal vascular lesions in systemic lupus erythematosus and secondary antiphospholipid syndrome]. Vestn Oftalmol. 2005 Sep-Oct;121(5):31-6.

[3]Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006 Feb;4(2):295-306.

Figure 1. A) Forest plot of univariate analysis; B) Forest plot of multivariate logistic regression; C) Cluster analysis of variables.

Disclosure of Interests:

None declared

Accelerated Evolution of H7N9 Subtype Influenza Virus under Vaccination Pressure

No avian H7N9 outbreaks have occurred since the introduction of H7N9 inactivated vaccine in the fall of 2017. However, H7N9 is still prevalent in poultry. To surveil the prevalence, genetic characteristics, and antigenic changes of H7N9, over 7000 oropharyngeal and cloaca swab specimens were collected from live poultry markets and farms in 15 provinces of China from 2017 to 2019. A total of 85 influenza virus subtype H7N9 strains were isolated and 20 representative strains were selected for genetic analysis and antigenicity evaluation. Results indicated the decreased prevalence of low-pathogenic H7N9 strains while highly-pathogenic H7N9 strains became dominated since the introduction of vaccine. Phylogenetic analysis showed that strains from 2019 formed an independent small branch and were genetically distant to strains isolated in 2013-2018. Analysis of key amino acid sites showed that the virus strains may adapt to the host environment evolutionally through mutation. Our analysis predicted additional potential glycosylation sites for HA and NA genes in the 2019 strains. Sequence analysis of HA gene in strains isolated from 2018 to 2019 showed that there were an increased nucleotide substitution rate and an increased mutation rate in the first and second nucleotides of coding codons within the open reading frame. The hemagglutination inhibition (HI) assay showed that H7-Re1 and H7-Re2 exhibited a lower HI titer for isolates from 2019, while H7-Re3 and rLN79 showed a high HI titer. The protective effect of the vaccine decreased after 15 months of use. Overall, under vaccination pressure, the evolution of influenza virus subtype H7N9 has accelerated.

Genomic evolution, transmission dynamics, and pathogenicity of avian influenza A (H5N8) viruses emerging in China, 2020

Multiple recent outbreaks of highly pathogenic H5N8 viruses originating in aquatic birds frequently occurred in most European countries, Russia, South Korea, and Japan during the winter of 2020–21, and one zoonotic event of poultry workers infected with novel H5N8 viruses were reported in Russia. Strikingly, these novel H5N8 viruses had emerged and been co-circulating in wild birds and poultry in multiple provinces of China during 2020–21. In China, the population of aquatic birds has risen significantly in the past twenty years, and China is regarded as the largest reservoir for influenza viruses carried in aquatic birds across the globe. Hence, the co-circulation of these novel H5N8 viruses poses an alarming threat to not only poultry industry but also human health. In this study, we sequenced full-length genomes of these H5N8 viruses circulating in China. Phylogenetic analysis demonstrated that poultry-origin H5N8 viruses in China fell within wild birds-origin clade 2.3.4.4b H5N8 viruses from Europe during 2020–21, and notably, were genetically closely related to human-infecting H5N8 viruses in Russia. Moreover, they possessed several molecular markers associated with mammalian adaption. Bayesian coalescent analysis showed that these H5N8 viruses might have introduced into China during June–September 2020, suggesting that these H5N8 viruses might have introduced via wild bird migration or poultry trade. Besides, we also found that the effective population size of clade 2.3.4.4b H5N8 viruses dramatically increased during the winter season of 2020/21, as is consistent with previous increase of genetic diversity during the winter seasons of 2013/14 and 2016/17, which indicated that the wild bird migration accelerates the genetic diversity of these H5N8 viruses during the winter season of 2020/21. Notably, these novel H5N8 viruses were lethal to chickens and mice, highly transmissible to ducks, and were antigenically distinct from 2.3.4.4h H5 viruses circulating in China, posing considerable threats to public health. Our findings offer novel insights into the evolution and risk assessment of H5N8 viruses during the winter season of 2020–21.

Explaining heterogeneity of individual treatment causal effects by subgroup discovery: An observational case study in antibiotics treatment of acute rhino-sinusitis

OBJECTIVES

Individuals may respond differently to the same treatment, and there is a need to understand such heterogeneity of causal individual treatment effects. We propose and evaluate a modelling approach to better understand this heterogeneity from observational studies by identifying patient subgroups with a markedly deviating response to treatment. We illustrate this approach in a primary care case-study of antibiotic (AB) prescription on recovery from acute rhino-sinusitis (ARS).

METHODS

Our approach consists of four stages and is applied to a large dataset in primary care dataset of 24,392 patients suspected of suffering from ARS. We first identify pre-treatment variables that either confound the relationship between treatment and outcome or are risk factors of the outcome. Second, based on the pre-treatment variables we create Synthetic Random Forest (SRF) models to compute the potential outcomes and subsequently the causal individual treatment effect (ITE) estimates. Third, we perform subgroup discovery using the ITE estimates as outcomes to identify positive and negative responders. Fourth, we evaluate the predictive performance of the identified subgroups for predicting the outcome in two ways: the likelihood ratio test, and whether the subgroups are selected via the Akaike Information Criterion (AIC) using backward stepwise variable selection. We validate the whole modelling strategy by means of 10-fold-cross-validation.

RESULTS

Based on 20 pre-treatment variables, four subgroups (three for positive responders and one for negative responders) were identified. The log likelihood ratio tests showed that the subgroups were significant. Variable selection using the AIC kept two of the four subgroups, one for positive responders and one for negative responders. As for the validation of the whole modelling strategy, all reported measures (the number of pre-treatment variables associated with the outcome, number of subgroups, number of subgroups surviving variable selection and coverage) showed little variation.

CONCLUSIONS

With the proposed approach, we identified subgroups of positive and negative responders to treatment that markedly deviate from the mean response. The subgroups showed additive predictive value of the outcome. The modelling approach strategy was shown to be robust on this dataset. Our approach was thus able to discover understandable subgroups from observational data that have predictive value and which may be considered by the clinical users to get insight into who responds positively or negatively to a proposed treatment.

Development of an immunochromatographic strip for rapid detection of H7 subtype avian influenza viruses

BACKGROUND

H7N9 avian influenza virus (AIV) including highly and low pathogenic viruses have been detected in China since 2013. H7N9 AIV has a high mortality rate after infection in humans, and most human cases have close contacted with poultry in the live poultry market. Therefore, it is necessary to develop a rapid point-of-care testing (POCT) technique for H7N9 AIV detection.

METHODS

The H7N9 AIV was inactivated and purified, and was used as the antigen to immunize BALB/c. Twelve H7-HA specific monoclonal antibodies (McAbs) were produced through the hybridoma technique. The McAb 10A8 was conjugated with colloid gold as detecting antibody; McAb 9B6 was dispensed on the nitrocellulose membran as the capture test line and the Goat-anti mouse IgG antibody was dispensed as control line respectively. The immunochromatographic strip was prepared.

RESULTS

The analysis of ELISA and virus neutralization test showed that the obtained McAbs specifically recognized H7 HA. Based on the prepared strip, the detection of H7 AIV was achieved within 10 min. No cross-reaction occurred between H7 AIVs and other tested viruses. The detection limit of the strip for H7 was 2.4 log10EID50/0.1 mL for chicken swab samples.

CONCLUSION

The McAbs were specific for H7 and the immunochromatographic strip developed in this study was convenient, rapid and reliable for the detection of H7 AIV. The strip could provide an effective method for the rapid and early detection of H7 AIV.

Japanese encephalitis virus manipulates lysosomes membrane for RNA replication and utilizes autophagy components for intracellular growth

Japanese encephalitis virus is absolutely dependent on their host cells and has evolved various strategies to manipulate the cellular secretory pathways for viral replication. However, how cellular secretory pathways are hijacked, and the origin of the viral vesicles remains elusive during JEV replication. Here we show how JEV manipulates multiple components of the cellular secretory pathway, including autophagic machinery, to generate a superior environment for genome replication. We utilized double-strand RNA antibodies to label JEV RNA complex seeking the viral replication compartments and found that JEV genome replication takes place in lysosomes (LAMP1), not in autophagosomes (LC3). Subsequently, in situ hybridization results showed that viral RNAs (vRNAs) of JEV strongly colocalized with LAMP1. What surprised us was that JEV vRNAs markedly colocalized with LC3, indicating that autophagy plays an active role in JEV replication. Interestingly, we found that JEV utilized autophagic components for intracellular growth in an autophagy-dependent manner and the fusion of autophagosome-lysosome plays a positive role in JEV post-RNA replication processes. Collectively, our findings demonstrate that JEV can manipulate cellular secretory pathway to form genome replication organelles and exploit autophagy components for intracellular growth, providing new insights into the life cycle of JEV and uncovering an attractive target for antiviral drugs.

Genetic Evolution Characteristics of Genotype G57 Virus, A Dominant Genotype of H9N2 Avian Influenza Virus

This study aimed to investigate the genetic evolution of the H9N2 avian influenza virus (AIV). Whole genome phylogenetic trees were constructed based on 306 H9N2 avian influenza strains collected in China from 2014 to 2019. The results showed that eight gene sequences were clustered separately according to their dominant clades, and a total of 10 genotypes were identified (seven of which were novel types). Among them, G57 genotype was confirmed as the most prevalent genotype with a frequency of 94%. In China, the G57 genotype of H9N2 first emerged in 2007, and then became the most common genotype in 2013. Therefore, the nucleotide substitution rates of G57 genotype in HA and NA genes collected from 2007 to 2019 were estimated, and the positive selection pressure sites in the same data set were measured. Taking 2013 as the boundary, the time period was divided into two periods: 2007-2012 and 2013-2019. From 2007 to 2012, multiple genotypes coexisted and could bear the pressures from both nature and environment; while G57 genotype was still in the adaptation stage, subjected to less selection pressure and in the process of slow evolution. However, from 2013 to 2019, G57 became the dominant genotype, and most of the external pressure reacted on it. Moreover, G57 genotype showed better adaptability than other genotypes. From 2013 to 2019, the nucleotide substitution rates of the HA gene were increased, and the positive selection pressures on HA and NA genes were stronger compared to those from 2007 to 2012. To sum up, the absolutely dominant G57 genotype exhibited a relatively constant genotype frequency and experienced adaptive evolution and natural selection simultaneously during the monitoring period. Therefore, urgent attention and diligent surveillance of H9N2 avian influenza virus are becoming increasingly important.

Generation of recombinant influenza virus bearing strep tagged PB2 and effective identification of interactional host factors

The genome of influenza A virus is negative-sense and segmented RNA, which is transcribed and replicated by the viral RNA-dependent RNA polymerase (RdRp) during the virus life cycle. The viral RdRp is thought to be an important host range and virulence determinant factor, and the 627 site of PB2 subunit is a highly acceptable key site of RdRp function. Besides, the function of RdRp is modulated by several host factors. Identification of the host factors interacting with RdRp is of great interest. Here, we tried to explore an effective method to study virus-host interaction by rescuing replication-competent recombinant influenza viruses carrying Strep tagged PB2. Subsequently, we tested several biological characteristics of recombinant viruses in cells and pathogenicity in mice. Then, we purified of protein complex of Strep tagged PB2 and host factors of interest from 293 T cells infected with recombinant viruses. After purification, we performed mass spectrometry to identify these proteins that interacting with PB2. We identified 57 host factors in total. Through Gene Ontology (GO) and Protein-Protein interaction (PPI) network analysis, we revealed the function and network of these proteins. In summary, we generated replication-competent recombinant influenza viruses by inserting a Strep-Tag into PB2 and purified host factors interacting with viral RdRp bearing a 627 K or 627E PB2. These proteins might function as host range and virulence determinants of influenza virus.

Influenza A virus protein PA-X suppresses host Ankrd17-mediated immune responses

Influenza A virus (IAV) PA-X is a critical ribonuclease protein involved in host cell shutoff but its role in modulating the host immune response to IAV infection remains to be addressed. In this study, host cellular proteins that directly interact with PA-X were screened to investigate the biological function of PA-X in the pathogenesis of IAV infection. The protein ankyrin repeat domain 17 (Ankrd17), a positive regulator of inflammatory responses via the retinoic acid-inducible gene-I (RIG-I)-like receptor (RLR) signaling pathway, was identified as a specific PA-X binding partner that preferred PA-X to the PA protein. The N-terminal ankyrin repeats of Ankrd17 are the key domain for the interaction with PA-X rather than PA, which is required for the function of Ankrd17 in elevating the host immune response. Using Ankrd17 knockout and overexpression, we confirmed that PA-X significantly affected the Ankrd17-mediated response to infection in host cells. Our data therefore reveal a novel function for PA-X in the regulation of innate immune pathways via the interaction between PA-X and Ankrd17.