Background: The clinical implications of myelin oligodendrocyte glycoprotein autoantibodies (MOG-Abs) are increasing. Establishing MOG-Ab assays is essential for effectively treating patients with MOG-Abs. We established an in-house cell-based assay (CBA) to detect MOG-Abs to identify correlations with patients’ clinical characteristics. Methods: We established the CBA using HEK 293 cells transiently overexpressing fulllength human MOG, tested it against 166 samples from a multicenter registry of central nervous system (CNS) inflammatory disorders, and compared the results with those of the Oxford MOG-Ab-based CBA and a commercial MOG-Ab CBA kit. We recruited additional patients with MOG-Abs and compared the clinical characteristics of MOG-Ab-associated disease (MOGAD) with those of neuromyelitis optica spectrum disorder (NMOSD). Results: Of 166 samples tested, 10 tested positive for MOG-Abs, with optic neuritis (ON) being the most common manifestation (4/15, 26.7%). The in-house and Oxford MOG-Ab CBAs agreed for 164/166 (98.8%) samples (κ = 0.883, P < 0.001); two patients (2/166, 1.2%) were only positive in our in-house CBA, and the CBA scores of the two laboratories correlated well (r = 0.663, P < 0.001). The commercial MOG-Ab CBA kit showed one falsenegative and three false-positive results. The clinical presentation at disease onset differed between MOGAD and NMOSD; ON was the most frequent manifestation in MOGAD, and transverse myelitis was most frequent in NMOSD. Conclusions The in-house CBA for MOG-Abs demonstrated reliable results and can potentially be used to evaluate CNS inflammatory disorders. A comprehensive, long-term study with a large patient population would clarify the clinical significance of MOG-Abs.

Despite the availability of direct-acting antivirals (DAAs) for chronic hepatitis C virus (HCV) infection in Korea, need remains for pangenotypic regimens that can be used in the presence of hepatic impairment, comorbidities, or prior treatment failure. We investigated the efficacy and safety of sofosbuvir–velpatasvir and sofosbuvir–velpatasvir–voxilaprevir for 12 weeks in HCV-infected Korean adults. Methods: This Phase 3b, multicenter, open-label study included 2 cohorts. In Cohort 1, participants with HCV genotype 1 or 2 and who were treatment-naive or treatment-experienced with interferon-based treatments, received sofosbuvir–velpatasvir 400/100 mg/day. In Cohort 2, HCV genotype 1 infected individuals who previously received an NS5A inhibitor-containing regimen ≥ 4 weeks received sofosbuvir–velpatasvir–voxilaprevir 400/100/100 mg/day. Decompensated cirrhosis was an exclusion criterion. The primary endpoint was SVR12, defined as HCV RNA < 15 IU/mL 12 weeks following treatment. Results: Of 53 participants receiving sofosbuvir–velpatasvir, 52 (98.1%) achieved SVR12. The single participant who did not achieve SVR12 experienced an asymptomatic Grade 3 ASL/ALT elevation on day 15 and discontinued treatment. The event resolved without intervention. All 33 participants (100%) treated with sofosbuvir–velpatasvir–voxilaprevir achieved SVR 12. Overall, sofosbuvir–velpatasvir and sofosbuvir–velpatasvir–voxilaprevir were safe and well tolerated. Three participants (5.6%) in Cohort 1 and 1 participant (3.0%) in Cohort 2 had serious adverse events, but none were considered treatment-related. No deaths or grade 4 laboratory abnormalities were reported. Conclusions: Treatment with sofosbuvir–velpatasvir or sofosbuvir–velpatasvir–voxilaprevir was safe and resulted in high SVR12 rates in Korean HCV patients.

BACKGROUND: Bone marrow-derived mesenchymal stem cells (BMSCs) and bone morphogenetic protein-2 (BMP-2) have been studied for bone repair because they have regenerative potential to differentiate into osteoblasts. The development of injectable and in situ three-dimensional (3D) scaffolds to proliferate and differentiate BMSCs and deliver BMP-2 is a crucial technology in BMSC-based tissue engineering. METHODS: The proliferation of mouse BMSCs (mBMSCs) in collagen/poly-γ-glutamic acid (Col/γ-PGA) hydrogel was evaluated using LIVE/DEAD and acridine orange and propidium iodide assays. In vitro osteogenic differentiation and the gene expression level of Col/γ-PGA(mBMSC/BMP-2) were assessed by alizarin red S staining and quantitative reversetranscription polymerase chain reaction. The bone regeneration effect of Col/γ-PGA(mBMSC/BMP-2) was evaluated in a mouse calvarial bone defect model. The cranial bones of the mice were monitored by micro-computed tomography and histological analysis. RESULTS: The developed Col/γ-PGA hydrogel showed low viscosity below ambient temperature, while it provided a high elastic modulus and viscous modulus at body temperature. After gelation, the Col/γ-PGA hydrogel showed a 3D and interconnected porous structure, which helped the effective proliferation of BMSCs with BMP-2. The Col/γ-PGA (mBMSC/BMP-2) expressed more osteogenic genes and showed effective orthotopic bone formation in a mouse model with a critical-sized bone defect in only 3–4 weeks. CONCLUSION The Col/γ-PGA(mBMSC/BMP-2) hydrogel was suggested to be a promising platform by combining collagen as a major component of the extracellular matrix and γ-PGA as a viscosity reducer for easy handling at room temperature in BMSC-based bone tissue engineering scaffolds.

Background/Aims: The safety of direct oral anticoagulants (DOACs) compared with warfarin in patients with both nonvalvular atrial fibrillation (AF) and clinically confirmed liver cirrhosis (LC) has not been well studied. We compared the risk of a major bleeding event between DOAC and warfarin treatments in this patient population. Methods: A total of 238 cirrhotic patients with AF were retrospectively analyzed. The major bleeding event risk was compared between DOAC- and warfarin-treated groups. The median follow-up duration was 5.6 years. Results: Among the 238 study patients with LC and AF, 128 (53.8%) received DOACs and 110 (46.2%) received warfarin. The mean patient age was 68.8 years, and 78.2% were men. A major bleeding event occurred in 10 and 20 patients in the DOAC and warfarin groups, respectively, most commonly caused by gastrointestinal bleeding (70.0%). The cumulative risk of major bleeding did not differ between the groups by log-rank test (p = 0.12). This finding did not change when using 60 propensity score-matched pairs. A multivariable Cox regression model indicated that the concomitant use of antiplatelet agents (adjusted hazard ratio [aHR], 2.06; 95% confidence interval [CI], 1.00 to 4.30; p = 0.048) and presence of esophageal or gastric varices confirmed by endoscopic examination (aHR, 2.31; 95% CI, 1.03 to 5.17; p = 0.04) were associated with major bleeding in the entire cohort. Conclusions A major bleeding event risk is not increased by DOAC compared with warfarin treatment. Antiplatelet agent use and varices are independently associated with a higher risk of major bleeding during anticoagulation.

Background/Aims: We examined the efficacy and safety of tegoprazan as a part of first-line triple therapy for Helicobacter pylori eradication. Methods: A randomized, double-blind, controlled, multicenter study was performed to evaluate whether tegoprazan (50 mg)-based triple therapy (TPZ) was noninferior to lansoprazole (30 mg)-based triple therapy (LPZ) (with amoxicillin 1 g and clarithromycin 500 mg; all administered twice daily for 7 days) for treating H. pylori. The primary endpoint was the H. pylori eradication rate. Subgroup analyses were performed according to the cytochrome P450 (CYP) 2C19 genotype, the minimum inhibitory concentration (MIC) of amoxicillin and clarithromycin, and underlying gastric diseases. Results: In total, 350 H. pylori-positive patients were randomly allocated to the TPZ or LPZ group. The H. pylori eradication rates in the TPZ and LPZ groups were 62.86% (110/175) and 60.57% (106/175) in an intention-to-treat analysis and 69.33% (104/150) and 67.33% (101/150) in a per-protocol analysis (non-inferiority test, p=0.009 and p=0.013), respectively. Subgroup analyses according to MICs or CYP2C19 did not show remarkable differences in eradication rate. Both first-line triple therapies were well-tolerated with no notable differences. Conclusions TPZ is as effective as proton pump inhibitor-based triple therapy and is as safe as first-line H. pylori eradication therapy but does not overcome the clarithromycin resistance of H. pylori in Korea

Background: The aim of this study was to investigate inhaler device handling in elderly patients. Inhaler devices with respect to misuse and error correction were also compared. Methods: Inhaler use technique was assessed using standardized checklists at the first visit and 3-month follow-up visit after retraining. The primary outcome was difference in the acceptable use ratio among inhaler devices. Secondary outcomes included differences in error correction, the most common step of misuse, and factors affecting the accuracy of inhaler use. Results: A total of 251 patients (mean age, 76.4 years) were included. The handling of 320 devices was assessed in the study. All patients had been trained before. However, only 24.7% of them used inhalers correctly. Proportions of acceptable use for Evohaler, Respimat, Turbuhaler, Ellipta, and Breezhaler/Handihaler were 38.7%, 50.0%, 61.4%, 60.8%, and 43.2%, respectively (p=0.026). At the second visit, the acceptable use ratio had increased. There were no significant differences among inhaler types (Evohaler, 63.9%; Respimat, 86.1%; Turbuhaler, 74.3%; Ellipta, 64.6%; and Breezhaler/Handihaler, 65.3% [p=0.129]). In multivariate analysis, body mass index, Turbuhaler, and Ellipta showed positive correlations with acceptable use of inhalers, whereas Chronic Obstructive Pulmonary Disease Assessment Test score showed a negative correlation. Conclusion Although new inhalers have been developed, the accuracy of inhaler use remains low. Elderly patients showed more errors when using pressurized metered-dose inhalers than using dry powder inhalers and soft-mist inhalers. However, there were no significant differences in misuse among inhaler devices after individual training. Results of this study suggests that repeat training is more important than inhaler type.

Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.

Purpose: The introduction of immune checkpoint inhibitors represents a major advance in the treatment of lung cancer, allowing sustained recovery in a significant proportion of patients. Nivolumab is a monoclonal anti–programmed death cell protein 1 antibody licensed for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC) after prior chemotherapy. In this study, we describe the demographic and clinical outcomes of patients with advanced NSCLC treated with nivolumab in the Korean expanded access program. Materials and Methods: Previously treated patients with advanced non-squamous and squamous NSCLC patients received nivolumab at 3 mg/kg every 2 weeks up to 36 months. Efficacy data including investigator-assessed tumor response, progression data, survival, and safety data were collected. Results: Two hundred ninety-nine patients were treated across 36 Korean centers. The objective response rate and disease control rate were 18% and 49%, respectively; the median progression-free survival was 2.1 months (95% confidence interval [CI], 1.87 to 3.45), and the overall survival (OS) was 13.2 months (95% CI, 10.6 to 18.9). Patients with smoking history and patients who experienced immune-related adverse events showed a prolonged OS. Cox regression analysis identified smoking history, presence of immune-related adverse events as positive factors associated with OS, while liver metastasis was a negative factor associated with OS. The safety profile was generally comparable to previously reported data. Conclusion This real-world analysis supports the use of nivolumab for pretreated NSCLC patients, including those with an older age.

Background/Aims: Frequent bleeding after endoscopic resection (ER) has been reported in patients with end-stage renal disease (ESRD). We aimed to evaluate the association and clinical significance of bleeding with ER in ESRD patients on dialysis. Methods: Between February 2008 and December 2018, 7,571 patients, including 47 ESRD patients on dialysis who underwent ER for gastric neoplasia, were enrolled. A total of 47 ESRDpatients on dialysis were propensity score-matched 1:10 to 470 non-ESRD patients, to adjust for between-group differences in variables such as age, sex, comorbidities, anticoagulation use, tumor characteristics, and ER method. Matching was performed using an optimal matching algorithm. For the matched data, clustered comparisons were performed using the generalized estimating equation method. Medical records were retrospectively reviewed. Frequency and outcomes of post-ER bleeding were evaluated. Results: Bleeding was more frequent in the ESRD with dialysis group than in the non-ESRD group. ESRD with dialysis conferred a significant risk of post-ER bleeding (odds ratio, 6.1; 95% confidence interval, 2.7–13.6; p<0.0001). All post-ER bleeding events were controlled using endoscopic hemostasis except in 1 non-ESRD case that needed surgery. Conclusions ESRD with dialysis confers a bleeding risk after ER. However, all bleeding events could be managed endoscopically without sequelae. Concern about bleeding should not stop endoscopists from performing ER in ESRD patients on dialysis.

Background: Although neuromyelitis optica spectrum disorder (NMOSD) is known to be a rare disease, its prevalence and incidence have not yet been studied in Korea. We performed a population-based study to examine the prevalence and incidence of NMOSD in Korea using data from the Korean National Health Insurance (NHI) claims database. Methods: Data from 2013 to 2017 were obtained, with a washout period set as 2013 and 2014. The prevalence and incidence of NMOSD in 2016 and 2017 were calculated using population census data. Subjects were divided into 5 groups at 15-year intervals, depending on the age at which the diagnostic code was entered. The relative risk (RR) for each age group was compared with the oldest (≥ 60 years) age group. Results: The overall prevalence was estimated to be 3.36 and 3.56 per 100,000 individuals, with an incidence of 0.41 and 0.65 per 100,000 individuals-year in 2016 and 2017, respectively. The mean age was 43.08 (standard deviation, 14.56) years, and the ratio of male to females was 1:4.7. The incidence was higher in female individuals aged between 30 and 59 years (RR, 2.8–3.05; P < 0.05). Conclusion Nationwide prevalence of NMOSD in Korea was 3.36 and 3.56/100,000 and its incidence was 0.41 and 0.65/100,000-year in 2016 and 2017 respectively.