COVID-19 Vaccine-Associated Pneumonitis in the Republic of Korea: A Nationwide Multicenter Survey.

BACKGROUND: Recent reports have suggested that pneumonitis is a rare complication following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, its clinical features and outcomes are not well known. The aim of this study was to identify the clinical characteristics and outcomes of patients with vaccine-associated pneumonitis following vaccination against SARS-CoV-2. METHODS: In this nationwide multicenter survey study, questionnaires were distributed to pulmonary physicians in referral hospitals. They were asked to report cases of development or exacerbation of interstitial lung disease (ILD) associated with the coronavirus disease 2019 vaccine. Vaccine-associated pneumonitis was defined as new pulmonary infiltrates documented on chest computed tomography within 4 weeks of vaccination and exclusion of other possible etiologies. RESULTS: From the survey, 49 cases of vaccine-associated pneumonitis were identified between February 27 and October 30, 2021. After multidisciplinary discussion, 46 cases were analyzed. The median age was 66 years and 28 (61%) were male. The median interval between vaccination and respiratory symptoms was 5 days. There were 20 (43%), 17 (37%), and nine (19%) patients with newly identified pneumonitis, exacerbation of pre-diagnosed ILD, and undetermined pre-existing ILD, respectively. The administered vaccines were BNT162b2 and ChAdOx1 nCov-19/AZD1222 each in 21 patients followed by mRNA-1273 in three, and Ad26.COV2.S in one patient. Except for five patients with mild disease, 41 (89%) patients were treated with corticosteroid. Significant improvement was observed in 26 (57%) patients including four patients who did not receive treatment. However, ILD aggravated in 9 (20%) patients despite treatment. Mortality was observed in eight (17%) patients. CONCLUSION: These results suggest pneumonitis as a potentially significant safety concern for vaccines against SARS-CoV-2. Clinical awareness and patient education are necessary for early recognition and prompt management. Additional research is warranted to identify the epidemiology and characterize the pathophysiology of vaccine-associated pneumonitis.

Triple primary lung cancer: a case report.

BACKGROUND: The risk of developing lung cancer is increased in smokers, patients with chronic obstructive pulmonary disease, individuals exposed to environmental carcinogens, and those with a history of lung cancer. Automobile exhaust fumes containing carcinogens are a risk factor for lung cancer. However, we go through life unaware of the fact that automobile exhaust is the cause of cancer. Especially, in lung cancer patient, it is important to search out pre-existing risk factors and advice to avoid them, and monitor carefully for recurrence after treatment. CASE PRESENTATION: This is the first report of a case with triple lung cancers with different histologic types at different sites, observed in a 76-year-old parking attendant. The first adenocarcinoma and the second squamous cell carcinoma were treated with stereotactic radiosurgery because the patient did not want to undergo surgery. Although the patient stopped intermittent smoking after the diagnosis, he continued working as a parking attendant in the parking lot. After 29 months from the first treatment, the patient developed a third new small cell lung cancer; he was being treated with chemoradiation. CONCLUSIONS: New mass after treatment of lung cancer might be a multiple primary lung cancer rather than metastasis. Thus, precision evaluation is important. This paper highlights the risk factors for lung cancer that are easily overlooked but should not be dismissed, and the necessity of discussion with patients for the surveillance after lung cancer treatment. We should look over carefully the environmental carcinogens already exposed, and counsel to avoid pre-existing lung cancer risk factors at work or residence in patients with lung cancer.

Comparison of clinical characteristics between chronic bronchitis and non-chronic bronchitis in patients with chronic obstructive pulmonary disease.

BACKGROUND: Chronic bronchitis (CB) is associated with poor outcomes in patients with chronic obstructive pulmonary disease. The aim of this study was to identify the characteristics that distinguish chronic bronchitis (CB) from non-CB. In addition, the features of mild CB versus severe CB were compared and a cut-off level was defined according to CAT1 and CAT2 scores. METHODS: This study was based on the Korea COPD Subgroup Study (KOCOSS) database, constructed in a multicenter COPD cohort study that recruited patients from 54 centers. CB was defined as CAT1 and CAT2 scores ≥ 3; severe CB was defined as CAT1 and CAT2 scores ≥ 4, while mild CB was defined as either a CAT1 or a CAT2 score < 4. Baseline characteristics, 1-year exacerbation rate, and 3-year FEV1 decline were compared in non-CB versus CB patients and in patients with mild CB versus severe CB. RESULTS: Among the 2162 patients enrolled in this study, 497 (23%) had CB. These patients were more likely than non-CB patients to be current smokers; they also had higher symptom and depression/anxiety scores. Lung function tests showed lower FEV1, FEV1/FVC, and DLco values in CB patients. Among CB patients, 67.6% had mild disease. Symptom and depression/anxiety scores were worse in patients with severe CB than in patients with mild CB. There were no significant differences in the lung function tests of the two groups. Analysis of 1-year exacerbation rates in CB patients and non-CB patients revealed that patients with CB more frequently had moderate-to-severe exacerbations (OR = 1.46, p < 0.01). More severe exacerbation was also present in patients with severe CB than in patients with mild CB (OR = 2.52, p = 0.01). The difference in annual FEV1 decline rate did not significantly differ either between CB patients and non-CB patients or between patients with severe CB and patients with mild CB. CONCLUSIONS: CB patients had worse symptoms and lung function than non-CB patients; CB patients also had more frequent moderate-to-severe exacerbation. Patients with severe CB had higher symptom scores and more frequent severe exacerbation than did patients with mild CB.

E-cigarette-associated Severe Pneumonia in Korea Using Data Linkage between the Korea National Health and Nutrition Examination Survey (KNHANES, 2013-2019) and the National Health Insurance Service (NHIS) Claims Database.

BACKGROUND: This study aimed to investigate the association between e-cigarette (EC) use and development of acute severe pneumonia in the Korean population using a national database. METHODS: We conducted a retrospective analysis using linkage of data between the Korean National Health and Nutrition Examination Survey (KNHANES) and the National Health Insurance Service (NHIS) administrative claims database. The primary endpoint of this study was development of severe pneumonia requiring hospital admission according to EC use during the study period. The secondary endpoints were in-hospital mortality, intensive care unit (ICU) admission, ventilator care, and days of hospital stay. RESULTS: The final analysis included 28,950 individuals, of which 578 (2.0%) were EC users. EC users were younger and more often male than non-EC users. The EC users showed higher level of education and household income and had fewer comorbidities. Severe pneumonia was noted in 37 of 28,372 non-EC users (0.13%), but there were no occurrences of severe pneumonia in EC users. The incidence of pneumonia occurrence was not different between the two groups (P = 1.000). CONCLUSIONS: Since e-cigarette or vaping use-associated lung injury (EVALI) is most likely included in acute severe pneumonia occurring within 3 months of EC use, it is considered that there might be no EVALI patients in Korea during the investigation period. A large-scale, prospective study is necessary to evaluate the association between EC use and acute lung injury.

Validation of Previous Spirometric Reference Equations and New Equations.

BACKGROUND: Pulmonary functions are interpreted using predicted values from reference equations that vary with ethnicity, gender, age, height, and weight. The universally used Choi's reference equations are not validated for Korean populations, and the purpose of this study was to validate them and develop new reference equations. METHODS: Subjects with normal spirometry and chest radiographs, no co-morbidities, and non-smokers, from the Korean National Health and National Examination Survey (KNHANES)-VI were enrolled (n = 117). Intraclass correlation coefficient (ICC) was assessed for reliability of reference equations. New reference equations were developed using linear regression analysis. Differences between observed and predicted values were assessed to compare the reference equations from Choi's, Global Lung Function Initiative 2012, KNHANES-IV, and newly developed equations. RESULTS: The ICC of Choi's reference equations was 0.854 (P < 0.001). The new reference equations for men were: forced vital capacity (FVC) (L) = - 4.38775 - 0.01184 × age + 0.05547 × height, forced expiratory volume - 1 second (FEV1) (L) = - 2.40147 - 0.02134 × age + 0.04103 × height; and for women: FVC (L) = - 3.09063 + 0.003904 × age + 0.038694 × height; FEV1 (L) = - 1.32933 - 0.00872 × age + 0.02762 × height. The differences between the predicted and observed means were largest in Choi's equations, but lowest in the new equations with highest goodness of fit. CONCLUSION: Because Choi's reference equations presented larger differences from the observed values, despite reliability, and the new reference equations showed better goodness of fit, we suggest the latter for Korean populations.

The RNA in reticulocytes is not just debris: it is necessary for the final stages of erythrocyte formation.

Reticulocytes contain both RNA and micro-organelles and represent the last stage of erythropoiesis before full maturation to red blood cells (RBCs). Even though there is continuing synthesis of hemoglobin and membrane-bound proteins in reticulocytes, the small amount of RNA that they contain has been regarded as non-functional residual material. Here we show that this residual RNA is both functional and essential for further reticulocyte maturation. Reticulocytes from which the remnant RNA had been removed by exposure to RNase did not survive or mature into RBCs in either humans or mice. Conversely, reticulocytes treated with an RNase Inhibitor were able to form normal biconcave cells. Similarly, poor survival was also seen in reticulocytes in which protein synthesis had been blocked. To identify the signaling pathways involved we isolated RNAs in reticulocytes versus those present in fully matured erythroblasts cultured from hematopoietic stem cells. RNAs found in erythroblasts were related to exocytosis, metabolism, and signal transduction all of which are critical for maturation through reticulocyte and into a fully mature, biconcave erythrocyte. Our results suggest that the mRNA in reticulocytes has to be translated into novel proteins that act to preserve mitochondria and maintain cell membrane integrity as reticulocytes mature. These results enhance our understanding of the final stage of erythropoiesis and may clarify why in vitro-generated reticulocytes for transfusion purposes survive poorly.

Association of lung function genes with chronic obstructive pulmonary disease.

BACKGROUND: Spirometric measurements of pulmonary function are important in diagnosing and determining the severity of chronic obstructive pulmonary disease (COPD). We performed this study to determine whether candidate genes identified in genome-wide association studies of spirometric measurements were associated with COPD and if they interacted with smoking intensity. METHODS: The current analysis included 1,000 COPD subjects and 1,000 controls recruited from 24 hospital-based pulmonary clinics. Thirteen SNPs, chosen based on genome-wide association studies of spirometric measurements in the Korean population cohorts, were genotyped. Genetic association tests were performed, adjusting for age, sex, and smoking intensity, using models including a SNP-by-smoking interaction term. RESULTS: PID1 and FAM13A were significantly associated with COPD susceptibility. There were also significant interactions between SNPs in ACN9 and FAM13A and smoking pack-years, and an association of ACN9 with COPD in the lowest smoking tertile. The risk allele of FAM13A was associated with increased expression of FAM13A in the lung. CONCLUSIONS: We have validated associations of FAM13A and PID1 with COPD. ACN9 showed significant interaction with smoking and is a potential candidate gene for COPD. Significant associations of genetic variants of FAM13A with gene expression levels suggest that the associated loci may act as genetic regulatory elements for FAM13A gene expression.

Clinical demographics and outcomes in mechanically ventilated patients in Korean intensive care units.

Knowledge of clinical demographics and outcomes of mechanically ventilated patients is important but there are few prospectively collected data in Korea. The objective of the present study was to describe the current status of mechanically ventilated patients in Korea as of 2010. We analyzed the data of Korean patients (275 patients in 12 Korean intensive care units [ICU]) participating in a multinational prospective cohort study on mechanical ventilation. The most common indication for mechanical ventilation was pneumonia (23%). Pressure-limited ventilation modes were preferred over volume-cycled ventilation modes. Non-invasive positive pressure ventilation was used in only seven (2%) patients as the initial ventilatory support. Median duration of mechanical ventilation was 7 days and ICU mortality was 36%. The multiple logistic regression model revealed that the Simplified Acute Physiology Score II (SAPS II) score at ICU admission (odds ratio [OR], 1.034; 95% confidence interval [CI], 1.001-1.036; P=0.033), peak pressure (OR, 1.054; 95% CI, 1.016-1.095; P=0.006), and the number of failed organs (OR, 2.132; 95% CI, 1.634-2.781; P<0.001) were independently associated with ICU mortality. This study provides a snapshot of current practice of mechanical ventilation in Korea.

Cardiovascular Events According to Inhaler Therapy and Comorbidities in Chronic Obstructive Pulmonary Disease.

Background: COPD coexists with many concurrent comorbidities. Cardiovascular complications are deemed to be major causes of death in COPD. Although inhaler therapy is the main therapeutic intervention in COPD, cardiovascular events accompanying inhaler therapy require further investigation. Therefore, this study aimed to investigate new development of cardiovascular events according to each inhaler therapy and comorbidities. Methods: This study analyzed COPD patients (age ≥ 40 years, N = 199,772) from the Health Insurance Review and Assessment Service (HIRA) database in Korea. The development of cardiovascular events, from the index date to December 31, 2020, was investigated. The cohort was eventually divided into three arms: the LAMA/LABA group (N = 28,322), the ICS/LABA group (N = 11,812), and the triple group (LAMA/ICS/LABA therapy, N = 6174). Results: Multivariable Cox analyses demonstrated that, compared to ICS/LABA therapy, triple therapy was independently associated with the development of ischemic heart disease (HR: 1.22, 95% CI: 1.04-1.43), heart failure (HR: 1.45, 95% CI: 1.14-1.84), arrhythmia (HR: 1.72, 95% CI: 1.41-2.09), and atrial fibrillation/flutter (HR: 2.31, 95% CI: 1.64-3.25), whereas the LAMA/LABA therapy did not show a significant association. Furthermore, emergency room visit during covariate assessment window was independently associated with the development of ischemic heart disease, heart failure, arrhythmia, and atrial fibrillation/flutter (p < 0.05). Conclusion: Our data suggest that cardiovascular risk should be considered in COPD patients receiving triple therapy, despite the confounding bias resulting from disparities in each group.

Current status of platelet manufacturing in 3D or bioreactors.

Blood shortages for transfusion are global issues of grave concern. As in vitro manufactured platelets are promising substitutes for blood donation, recent research has shown progresses including different cell sources, different bioreactors, and three-dimensional materials. The first-in-human clinical trial of cultured platelets using induced pluripotent stem cell-derived platelets began in Japan and demonstrated its quality, safety, and efficacy. A novel bioreactor with fluid motion for platelet production has been reported. Herein, we discuss various cell sources for blood cell production, recent advances in manufacturing processes, and clinical applications of cultured blood.

The Impact of Inhaled Corticosteroids on the Prognosis of Chronic Obstructive Pulmonary Disease.

Background: A comprehensive analysis of the effects of inhaled corticosteroids (ICS) on COPD in a real-world setting is required due to safety concerns regarding ICS in COPD. This study aimed to explore the impact of ICS on the prognosis of Asian COPD patients in the real-life world. Methods: We examined 978 COPD patients registered in the Korean National Health and Nutrition Examination Survey (KNHANES) database and with their data linked to Health Insurance and Review Assessment (HIRA) data. The outcome measures were ascertained by HIRA from January 1, 2009, to December 31, 2012. This study enrolled two arms; ICS users (N = 85, mean age = 66.7 ± 8.9 years) and non-ICS users (N = 893, mean age = 63.7 ± 9.7 years). Results: Compared to the non-ICS users, the ICS users had a higher rate of pneumonia, tuberculosis, and acute exacerbations (P<0.05). Hospitalization due to respiratory causes was also higher among ICS users (P<0.05). Multivariate analysis showed that acute exacerbation was independently associated with the development of pneumonia (P<0.05), whereas ICS therapy had a tendency to be associated with pneumonia. Another multivariate analysis demonstrated that old age, FEV1, ICS therapy, and pneumonia were independently associated with the occurrence of acute exacerbation (P<0.05). The concomitant pneumonia (HR = 3.353, P = 0.004) was independently associated with higher mortality (P<0.05). Conclusion: Our data demonstrated that the ICS users had a higher rate of pneumonia and tuberculosis and the concomitant pneumonia was independently associated with higher mortality, highlighting the importance of cautious and targeted administration of ICS in COPD.

New prognostic scoring system for mortality in idiopathic pulmonary fibrosis by modifying the gender, age, and physiology model with desaturation during the six-minute walk test.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial lung disease (ILD) with variable and heterogeneous clinical course. The GAP (gender, age, and physiology) model had been used to predict mortality in patients with IPF, but does not contain exercise capacity. Therefore, our aim in this study was to develop new prognostic scoring system in the Korea IPF Cohort (KICO) registry. Materials and methods: This is a retrospective study of Korean patients with IPF in KICO registry from June 2016 to August 2021. We developed new scoring system (the GAP6) based on the GAP model adding nadir saturation of percutaneous oxygen (SpO2) during six-minute walk test (6MWT) in the KICO registry and compared the efficacy of the GAP and the GAP6 model. Results: Among 2,412 patients in KICO registry, 966 patients were enrolled. The GAP6 model showed significant prognostic value for mortality between each stage [HR Stage II vs. Stage I = 2.89 (95% CI = 2.38-3.51), HR Stage III vs. Stage II = 2.68 (95% CI = 1.60-4.51)]. In comparison the model performance with area under curve (AUC) using receiver operating characteristic (ROC) curve analysis, the GAP6 model showed a significant improvement for predicting mortality than the GAP model (AUC the GAP vs. the GAP6, 0.646 vs. 0.671, p < 0.0019). Also, the C-index values slightly improved from 0.674 to 0.691 for mortality. Conclusion: The GAP6 model adding nadir SpO2 during 6WMT for an indicator of functional capacity improves prediction ability with C-index and AUC. Additional multinational study is needed to confirm these finding and validate the applicability and accuracy of this risk assessment system.

Radiation-induced pseudomembranous tracheobronchitis: A report of two cases.

Radiation therapy can cause radiation pneumonitis, organizing pneumonia, and lung fibrosis. Radiation-induced pseudomembranous bronchitis is a rare condition. Here, we describe a rare case each of pseudomembranous tracheobronchitis and pseudomembrane with total bronchial obstruction which developed after thoracic radiotherapy. A 50-year-old man presented paroxysmal severe cough 1 month after concurrent chemoradiotherapy for small-cell lung cancer. Bronchoscopy revealed a whitish membrane in the trachea and bronchus, which were the fields of radiation. Another 60-year-old man complained of dyspnea 7 months after radiation therapy for metastatic lymph node adenocarcinoma. Bronchoscopy demonstrated a membrane with total obstruction of right lower lobar bronchus, which was the area of radiation. The pathological findings of histological examination in both cases demonstrated radiation-induced pseudomembranous tracheobronchitis. Patients in both cases responded well to steroids and the pseudomembrane disappeared. If patients who have received thoracic radiation therapy complain of persistent cough, bronchoscopy may be helpful.

Pulmonary cryptococcosis after recovery from COVID-19 in an immunocompetent patient: A rare case report.

RATIONALE: Cryptococcus neoformans (C neoformans) infection typically occurs in immunocompromised patients infected with human immunodeficiency virus (HIV), or those taking immunosuppressive drugs, corticosteroids, or chemotherapy. Recently, there have been an increasing number of reports of cryptococcosis as opportunistic infections in COVID-19 patients, all of which have been related to immunocompromising conditions, underlying medical diseases, immune suppression drugs, or corticosteroids. Here, we report the first case of pulmonary cryptococcosis in an immunocompetent patient with a history of COVID-19 who had no history of underlying diseases or immune modulation drugs. PATIENT CONCERNS: A previously healthy 46-year-old man presented with tiny lung nodules. He had quit smoking 6 years prior. He had no significant medical history except for COVID-19 3 months prior, and had not received corticosteroids or cytokine blockers when he had COVID-19. He had been coughing since he recovered from COVID-19. DIAGNOSIS: Bronchoalveolar lavage cultures showed the growth of C neoformans. A CT-guided percutaneous needle biopsy of the lung lesion was performed. Histopathology of the biopsy specimen showed granulomas with encapsulated yeast. There was no growth of C neoformans in the CSF or blood. He was diagnosed with pulmonary cryptococcosis. INTERVENTION: Antifungal drug (fluconazole) was administered for 6 months in the outside clinic. OUTCOMES: The lung lesions disappeared after 6 months medication. LESSONS: This case may illustrate the risk of pulmonary cryptococcosis after SARS-CoV-2 infection in an immunocompetent patient. Opportunistic infections can occur even after recovery from COVID-19 for several reasons. First, SARS-CoV-2 infection causes immune dysregulation including lymphocytopenia. Second, T lymphocytes play a principal role against Cryptococcus. Third, these changes in the immune system due to COVID-19 may last for several weeks. Thus, we suggest careful consideration of lung lesions in patients with a history of COVID-19.

Broken Needle Embedded in the Body during Vascular Puncture.

The use of needles is essential in most medical procedures and surgery; however, needle breakage is not known to happen very frequently. Even if it does, it is most likely to occur during dental procedures, sutures, aspiration, biopsy, anesthesia, and drug abuse. To our knowledge, this is the first report about needle detachment from the syringe during a vascular puncture for blood collection. In this case, an 87-year-old obese woman with generalized edema had repeated vascular punctures to the femoral artery for arterial blood gas analysis (ABGA). After blood collection at this instance, when the syringe was pulled out, the needle was detached from it. Radiography revealed that the broken needle was lodged in the groin. A surgical incision with the fluoroscopic radiography located the embedded needle in the soft tissue and allowed the retrieval of its fragments from the groin soft tissue. Obesity and repeated punctures may increase the risk of needle breakage and prior inspection of needles for such procedures may be necessary.

Pneumocystis Pneumonia in a Non-Immunocompromised Lung Cancer Patient after Surgery: A Case Report.

We present the Pneumocystis pneumonia case of a 64-year-old man with no remarkable history except for hypertension, who had not undergone any treatment other than surgery. On postoperative day 7, high-resolution computed tomography findings revealed multifocal ground-glass opacifications with interlobular septal thickening in both lungs; therefore, atypical pneumonia was suspected. Polymerase chain reaction (PCR) test performed after bronchoalveolar lavage was positive for Pneumocystis jirovecii (P. jirovecii). Based on the PCR results, a final diagnosis of Pneumocystis pneumonia (PCP) was made. After treatment, he improved and was discharged. This is a unique case of PCP diagnosis in a non-immunocompromised patient, with no remarkable history except for hypertension, who had not undergone any treatment other than surgery for cancer. Thus, it is necessary to consider additional risk factors for PCP and timing of preventive treatment.

The role of nafamostat mesilate as a regional anticoagulant during extracorporeal membrane oxygenation.

BACKGROUND: Anticoagulation during extracorporeal membrane oxygenation (ECMO) usually is required to prevent thrombosis. The aim of this study was to investigate the usefulness of nafamostat mesilate (NM) as a regional anticoagulant during veno-arterial ECMO (VA-ECMO) treatment. METHODS: We retrospectively reviewed the medical records of 16 patients receiving VA-ECMO and NM from January 2017 to June 2020 at Haeundae Paik Hospital. We compared clinical and laboratory data, including activated partial thromboplastin time (aPTT), which was measured simultaneously in patients and the ECMO site, to estimate the efficacy of regional anticoagulation. RESULTS: The median patient age was 68.5 years, and 56.3% of patients were men. Cardiovascular disease was the most common primary disease (75.0%) requiring ECMO treatment, followed by respiratory disease (12.5%). The median duration of ECMO treatment was 7.5 days. Among 16 patients, seven were switched to NM after first using heparin as an anticoagulation agent, and nine received only NM. When comparing aPTT values in the NM group between patients and the ECMO site, that in patients was significantly lower than that at the ECMO site (73.57 vs. 79.25 seconds; P=0.010); in contrast, no difference was observed in the heparin group. CONCLUSIONS: NM showed efficacy as a regional anticoagulation method by sustaining a lower aPTT value compared to that measured at the ECMO site. NM should be considered as a safer regional anticoagulation method in VA-ECMO for patients at high risk of bleeding.

Association Between Vitamin D Level and Respiratory Symptoms in Patients with Stable Chronic Obstructive Pulmonary Disease.

Purpose: Vitamin D insufficiency or deficiency is prevalent in patients with chronic obstructive pulmonary disease (COPD). However, the association between vitamin D levels and respiratory symptoms in patients with stable COPD has not been fully investigated. This study evaluated the association between vitamin D levels and respiratory symptoms in patients with stable COPD. Patients and Methods: Patients with COPD who had their serum 25-hydroxyvitamin D (25-OH vitamin D) level measured within 6 months of spirometry between January 2016 and April 2020 were retrospectively included. Respiratory symptoms were assessed using the modified Medical Research Council (mMRC) scale and COPD assessment test (CAT) score. Results: Of the 329 included patients, 193, 88, and 48 were categorized as having vitamin D deficiency (<20 ng/mL), insufficiency (20-29 ng/mL), and sufficiency (≥30 ng/mL), respectively. The mean serum 25-OH vitamin D level of each group was 13.45 ng/mL, 24.61 ng/mL, and 38.90 ng/mL, respectively. Patients with vitamin D insufficiency/deficiency showed higher CAT scores than those with vitamin D sufficiency (p = 0.004). In multivariable adjusted models, vitamin D insufficiency/deficiency was significantly associated with a CAT score of 10 or more (adjusted odds ratio [aOR] = 2.41, 95% confidence interval [CI] = 1.20-4.82, p = 0.013) and mMRC ≥ 2 (aOR = 2.39, 95% CI = 1.08-5.32, p = 0.032). Among CAT items, the amount of phlegm (p = 0.008), chest tightness (p = 0.030), breathlessness walking upstairs (p < 0.001), home activity limitations (p = 0.002), and lack of energy (p = 0.003) were significantly associated with vitamin D insufficiency/deficiency after adjustment for age, sex, body mass index, smoking history, Charlson comorbidity index, post-bronchodilator forced expiratory volume in 1 second, and season of blood draw. Conclusion: Vitamin D insufficiency/deficiency were associated with worse respiratory symptoms in patients with stable COPD.

Polyhexamethylene guanidine phosphate-induced necrosis may be linked to pulmonary fibrosis.

Following the humidifier disinfectant incident in Korea, polyhexamethylene guanidine phosphate (PHMG-P) has been used to establish lung fibrosis model animals. Herein, we investigated time-dependent changes after a single PHMG-P instillation (22 µg/lung) to identify the underlying pathogenesis and immune response involved in PHMG-P-induced lung fibrosis. Compared to control mice, body weight loss and blood biochemical and hematological changes were more remarkable in PHMG-P-instilled mice, an increase of total cell counts, infiltration of macrophages and neutrophils and necrotic cell death were also more notable in the lungs of PHMG-P-instilled mice. Pathological lesions were detected from Day 1 after exposure, deteriorating with time. In addition, secretion of anti-inflammatory mediators was rapidly inhibited from 6 h after exposure, and level of IL-24, a tissue repair-related cytokine, was up-regulated in the lungs of PHMG-P-instilled mice until Day 21 post-exposure. In vitro tests using BEAS-2B cells showed that PHMG-P disturbed structural and functional homeostasis of organelles and that intracellular ROS increase was considered as an important cause of PHMG-P-induced cell death. Additionally, co-culture with DNA, a polyanionic compound, clearly inhibited PHMG-P-induced necrosis, and increased IL-1ß and TNF-α level and decreased IL-6 and IL-8 levels were observed following exposure to PHMG-P. Meanwhile, IL-8 secretion increased in cells exposed to PHMG-P-induced cell debris. Therefore, we suggest that necrotic cell debris may importantly contribute to the PHMG-P-induced inflammatory response and pathogenesis. In addition, PHMG-P-induced necrosis may be initiated by high affinity between PHMG-P and cell membrane.