Identification of exhaled volatile organic compounds that characterize asthma phenotypes: A J-VOCSA study.

BACKGROUND: Asthma is characterized by phenotypes of different clinical, demographic, and pathological characteristics. Identifying the profile of exhaled volatile organic compounds (VOCs) in asthma phenotypes may facilitate establishing biomarkers and understanding asthma background pathogenesis. This study aimed to identify exhaled VOCs that characterize severe asthma phenotypes among patients with asthma. METHODS: This was a multicenter cross-sectional study of patients with severe asthma in Japan. Clinical data were obtained from medical records, and questionnaires were collected. Exhaled breath was sampled and subjected to thermal desorption gas chromatography-mass spectrometry (GC/MS). RESULTS: Using the decision tree established in the previous nationwide asthma cohort study, 245 patients with asthma were divided into five phenotypes and subjected to exhaled VOC analysis with 50 healthy controls (HCs). GC/MS detected 243 VOCs in exhaled breath samples, and 142 frequently detected VOCs (50% of all samples) were used for statistical analyses. Cluster analysis assigning the groups with similar VOC profile patterns showed the highest similarities between phenotypes 3 and 4 (early-onset asthma phenotypes), followed by the similarities between phenotypes 1 and 2 (late-onset asthma phenotypes). Comparisons between phenotypes 1-5 and HC revealed 19 VOCs, in which only methanesulfonic anhydride showed p < 0.05 adjusted by false discovery rate (FDR). Comparison of these phenotypes yielded several VOCs showing different trends (p < 0.05); however, no VOCs showed p < 0.05 adjusted by FDR. CONCLUSIONS: Exhaled VOC profiles may be useful for distinguishing asthma and asthma phenotypes; however, these findings need to be validated, and their pathological roles should be clarified.

Low Serum IL-18 Levels May Predict the Effectiveness of Dupilumab in Severe Asthma.

Objective Dupilumab, a monoclonal antibody specific for the human interleukin (IL)-4 receptor α, is used to treat severe asthma, especially in patients with elevated blood eosinophil counts and fractional exhaled nitric oxide (FeNO). The therapeutic response to dupilumab is highly variable. In this study, we explored new serum biomarkers to accurately predict the effect of dupilumab and examine the effect of dupilumab based on changes in the clinical parameters and cytokine levels. Methods Seventeen patients with severe asthma treated with dupilumab were enrolled. Responders, defined as those with a >0.5-point decrease in the Asthma Control Questionnaire (ACQ) score after 6 months of treatment, were included. Results There were 10 responders and 7 non-responders. Serum type 2 cytokines were equivalent between responders and non-responders; the baseline serum IL-18 level was significantly lower in responders than in non-responders (responders, 194.9±51.0 pg/mL; non-responders, 323.4±122.7 pg/mL, p=0.013). The cut-off value of IL-18 at 230.5 pg/mL could be used to distinguish non-responders from responders (sensitivity 71.4, specificity 80.0, p=0.032). Conclusion A low baseline serum IL-18 level may be a useful predictor of an unfavorable response to dupilumab in terms of the ACQ-6.

Serum MMP3 and IL1-RA levels may be useful biomarkers for detecting asthma and chronic obstructive pulmonary disease overlap in patients with asthma.

Background: Asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO) is characterized by concurrent features of asthma and COPD. Since disease pathogenesis, severities, and treatments differ between asthma and ACO, it is important to differentiate them. Objective: To clarify and compare the characteristics of ACO and asthma and identify the serum biomarkers for differentiating them, especially in older patients. Methods: This study used the data of 639 participants from the nationwide cohort study, the NHOM-Asthma study, an asthma registry in Japan, with complete information on smoking history, respiratory function, and serum biomarkers. ACO was defined as the self-reported comorbidity of COPD or emphysema, or with obstructive pulmonary function and smoking history (pack-years≥10). The clinical characteristics of patients with ACO and asthma without COPD were compared. The serum biomarkers for differentiation were examined using receiver operating characteristic curves and multivariable analysis. The associations between the biomarkers and age were also analyzed. Results: Of the 639 asthma patients, 125 (19.6%) were diagnosed with ACO; these patients were older and male-dominant and had a higher prevalence of comorbidities such as hypertension, diabetes, and stroke. Among the serum biomarkers that were significantly different between ACO and asthma without COPD, the YKL-40/CHI3L1, MMP3, and IL-1RA levels showed a high area under the curve for discriminating ACO. Only the MMP3 and IL-1RA levels were significantly higher among ACO patients, regardless of age and sex; the YKL-40/CHI3L1 levels were not different due to the effect of age. Conclusion: MMP3 and IL-1RA may be useful serum biomarkers for distinguishing ACO from asthma.

Severe Asthma Where Eosinophilic Granulomatosis with Polyangiitis Became Apparent after the Discontinuation of Dupilumab.

The use of biologic agents has enabled control of severe asthma, but there is a risk that eosinophilic granulomatosis with polyangiitis (EGPA) may be masked in some cases. We herein report a 71-year-old man who was administered dupilumab for 2 years to stabilize his asthma symptoms. A few months after discontinuation of dupilumab administration, an increase in the eosinophil count in peripheral blood, leg pain, and a rash appeared. Based on pathology, he was diagnosed with EGPA. EGPA in this case was considered to have become apparent due to the discontinuation of dupilumab administration.

High serum cytokine levels may predict the responsiveness of patients with severe asthma to benralizumab.

OBJECTIVE: Benralizumab, a humanized monoclonal antibody against human IL-5 receptor alpha, is effective in treating eosinophilic severe asthma. However, patients' response to benralizumab varies widely. In this study, we aimed to identify a new serum biomarker to accurately predict benralizumab response. METHODS: Seventeen benralizumab-treated patients with severe eosinophilic asthma were enrolled. Blood samples were collected; pulmonary function tests were performed and questionnaires were disseminated at baseline and after 1, 2, 4, and 6 months of treatment. Blood cytokine levels were measured. Response was defined as an elevation in forced expiratory volume in 1 s of at least 10.4% from baseline after 4 months of treatment. RESULTS: There were nine respondents and eight non-respondents. The non-responders showed significantly higher baseline serum interferon-γ; interleukin (IL)-4, -5, -6, -7, and -12p70; IL-17/IL-17A; IL-17E/IL-25; IL-18/IL-1F4; chemokine (C-C motif) ligand (CCL)3/macrophage inflammatory protein (MIP)-1α; CCL4/MIP-1ß; CCL11/eotaxin; matrix metalloproteinase-12; tumor necrosis factor-α, and thymic stromal lymphopoietin levels. After benralizumab administration, the serum CCL3/MIP-1α and CCL11/eotaxin levels significantly and persistently increased in the responders (CCL3/MIP-1α, responders: 144.5 ± 37.9 pg/ml (baseline) vs. 210.3 ± 59.4 pg/ml (4 months), p = 0.009; non-responders: 270.8 ± 139.8 pg/ml (baseline) vs. 299.5 ± 159.9 pg/ml (4 months), p = 0.33; CCL11/eotaxin, responders: 167.9 ± 62.6 pg/ml (baseline) vs. 326.7 ± 134.4 pg/ml (4 months), p = 0.038; non-responders: 420.9 ± 323.1 pg/ml (baseline) vs. 502.1 ± 406.0 pg/ml (4 months), p = 0.30). CONCLUSION: Low baseline serum inflammatory cytokine levels may be useful in predicting a good benralizumab response.Supplemental data for this article is available online at at www.tandfonline.com/ijas .

Interrupted time-series analyses of routine vaccination program for elderly pneumonia patients in Japan; an ecological study using aggregated nationwide inpatient data.

A national routine pneumococcal pneumonia immunization program started in Japan in 2014. It targeted the population aged ≥65 years and used a 23-valent pneumococcal polysaccharide vaccine; PPSV23. However, its effectiveness was not well defined because of the lack of a comprehensive database on the PPSV23 vaccination status of each subject. We used interrupted time-series analyses to assess the changes in the incidence and prognosis of elderly patients hospitalized for pneumonia before and after initiation of the program. First, we estimated the PPSV23 coverage rates in subjects aged ≥65 years based on the number of shipped PPSV23 syringes and the estimated population in each prefecture. The estimated coverage rates reached around 40% in 2014 for the 3 Tohoku prefectures, while those in the other prefectures remained below 20%. After the national routine immunization program started, the estimated coverage rate increased significantly in every prefecture and exceeded 40% in 2017. Next, we aggregated the data extracted from the Japanese Diagnosis Procedure Combination database from April 2011 through February 2017 for hospitalized pneumonia patients aged ≥65 years. The data included data from 655,746 patients, excluding those in the 3 Tohoku prefectures. Interrupted time-series analyses found no change in the incidence of hospitalized pneumonia patients and in-hospital mortality after the vaccination program, but there was a decrease in the in-hospital mortality of pneumonia patients with severe comorbidities defined by the modified Charlson comorbidity index. These results suggest an association between the vaccination program and an improved outcome in hospitalized elderly pneumonia patients with severe comorbidities in Japan.

An autopsy case report of yellow nail syndrome coincided with primary biliary cholangitis.

Yellow nail syndrome (YNS) is a rare entity characterized by thickened yellowish nails, lymphedema and respiratory manifestations such as pleural effusion. Lymphatic dysfunction is considered as a cause of YNS. However, evidence of systemic dilatation/hyperplasia of lymphatics based on autopsy in YNS is not available. In this report, autopsy revealed dilatation and hyperplasia of lymphatic vessels in lungs, visceral and parietal pleurae, and intestines. We identified the direct opening of lymphatic vessels of the visceral pleura to the pleural cavity, which indicated the pathophysiology of uncontrollable pleural effusion in YNS. The current case was compromised with primary biliary cholangitis (PBC). The onset of PBC seemed to be related with the progression of YNS.

IL-1RA in the supernatant of QuantiFERON-TB Gold In-Tube and QuantiFERON-TB Gold Plus is useful for discriminating active tuberculosis from latent infection.

INTRODUCTION: The new-generation QuantiFERON (QFT)-TB Gold Plus (QFT-Plus) is expected to be useful because it includes a new peptide that is supposed to induce a CD8+ T cell response. There is a need for a new marker with sensitivity higher than that of the conventional IFN-γ release assays owing to false-negative results in the latter. This study aimed to compare cytokines in QFT-plus and QuantiFERON-Gold In-Tube (QFT-GIT) supernatants to discriminate between active tuberculosis and latent tuberculosis infection (LTBI). METHODS: A cross-sectional study was conducted at Tokyo National Hospital, wherein 21 LTBI patients and age and sex-matched active TB patients were randomly selected. The levels of various cytokines were measured and compared using the MAGPIX System, and receiver operating characteristic (ROC) curves were generated. RESULTS: IL-1RA, IFN-γ, CXCL10/IP-10, and CCL4/MIP-1ß levels were higher in the active TB group than in the LTBI group in QFT-GIT antigen (GIT Ag) tubes. In QFT-plus tubes, IL-1RA was higher in TB1 and TB2 tubes, while CCL2/MCP-1 was higher only in TB2 tubes. In Nil tubes, CCL5/RANTES, TNF-α, PDGF-BB, and IL-2 levels were significantly higher in the active TB group. IL-1RA in GIT Ag tubes showed the highest area under the curve of 0.8367. The sensitivity and specificity of IL-1RA were 66.7% (95% confidence interval [CI]: 43.0-85.4) and 90.5% (95% CI: 69.6-98.8), respectively, which were the highest among the cytokines. CONCLUSIONS: IL-1RA level in the QFT-GIT supernatant can be a good marker for discriminating active TB from LTBI.

Usefulness of Rapid Desensitization Therapy for Severe Rash Caused by Molecularly Targeted Drugs Used in the Treatment of Non-small-cell Lung Cancer.

Molecular-targeted drugs (MTDs), such as epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and anaplastic lymphoma kinase inhibitors, are used to treat non-small-cell lung cancer (NSCLC). The incidence of rash caused by EGFR-TKIs and discontinuation of MTDs because of rash are issues. Rapid desensitization therapy (RDT) was performed in five patients who developed severe rash after introduction of MTDs and was successful in four, all of whom showed no rash relapse. RDT may thus be useful for treating rash in patients receiving MTDs for NSCLC.

Comparison of QuantiFERON-TB Gold Plus, QuantiFERON-TB Gold In-Tube, and T-SPOT.TB among patients with tuberculosis.

OBJECTIVES: This study evaluated the efficacy of the following interferon (IFN)-γ release assays (IGRAs): QuantiFERON-TB Gold Plus (QFT-Plus), QFT-Gold In-Tube (QFT-GIT), and T-SPOT. TB (T-SPOT) with the quantitative values of IFN-γ response. METHODS: Blood samples were collected from patients with active tuberculosis (TB), latent TB infection (LTBI), individuals with previous TB infection, and healthy volunteers enrolled between May 2017 and June 2018. RESULTS: IGRAs results were analyzed in 175 subjects (76 had active TB, 14 had LTBI, 35 had prior TB infection, and 50 were healthy). QFT-Plus and QFT-GIT revealed equal efficacy for IFN-γ values, and the IFN-γ response in QFTs tended to increase with the spot counts in T-SPOT, with similar high sensitivities (approximately 90%) in the active TB group. The test concordance of two of three IGRAs was optimal among all subjects (κ coefficients: 0.82-0.96). Additionally, the median quantitative values of IFN-γ with QFT-Plus and QFT-GIT were higher in the active TB group than in the LTBI and previous TB groups. CONCLUSION: Three IGRAs showed equivalent efficacy with high sensitivities and higher IFN-γ response in active TB group than that in non-active TB group.

A Low Serum CCL4/MIP-1ß Level May Predict a Severe Asthmatic Responsiveness to Mepolizumab.

Objective Mepolizumab, a humanized anti-interleukin-5 monoclonal antibody, is effective for treating eosinophilic severe asthma. However, there is a need for more biomarkers that can predict the patient response to mepolizumab before starting therapy. This study aimed to identify a new biomarker in the serum that is able to accurately predict the responsiveness to mepolizumab. Methods This study enrolled 11 patients who had all been diagnosed with severe eosinophilic asthma and were then administered mepolizumab every 4 weeks for at least 4 months. Blood samples were collected, and pulmonary function tests and questionnaires were administered at baseline and after 4, 8 and 16 weeks of treatment. The response to mepolizumab was then assessed based on the difference in the Asthma Quality of Life Questionnaire (AQLQ) score after 16 weeks of mepolizumab therapy compared with that at baseline. Patients with an increase in the AQLQ score of more than 0.5 were defined as responders. The cytokine levels in the blood were measured by LUMINEX 200 and ELISA. Results There were 6 responders and 5 non-responders. The responders showed a significantly lower serum level of chemokine (C-C motif) ligand 4/macrophage inflammatory protein-1ß (CCL4/MIP-1ß) at baseline compared to the non-responders. Receiver operating characteristic curves to distinguish responders from non-responders using the baseline serum CCL4/MIP-1ß level showed a good area under the curve of 0.9. The non-responders showed a significant increase in the level of CCL4/MIP-1ß after 4 weeks compared to the baseline. Conclusion A low baseline serum CCL4/MIP-1ß level may be useful for predicting a good mepolizumab response in severe eosinophilic asthma.

Evaluation of cytokine levels using QuantiFERON-TB Gold Plus in patients with active tuberculosis.

OBJECTIVES: A recently released new QuantiFERON (QFT) product, QFT TB Gold plus (QFT-plus), is optimized for both CD4 and CD8 responses and reported to have higher sensitivity compared to the former QFT-3 G. Previously, using supernatants of QFT-3 G, we and others have demonstrated that cytokines other than IFN-γ may be useful in diagnosing tuberculosis. The present study aimed to identify cytokines that are useful for accurately diagnosing active tuberculosis by using QFT-plus and compared the data to those with QFT-3 G. METHODS: Eighty-three active tuberculosis patients and 70 healthy control subjects who were examined by QFT at Tokyo National Hospital from June 2017 to July 2018 were enrolled. QFT-3 G and QFT-plus were performed according to the manufacturer's instructions. At the same time, blood cell culture supernatants were collected and assayed for their cytokine levels using R&D Systems Luminex Assay and MAGPIX System. The levels of cytokines were compared between different antigen-containing tubes (3 G Ag, TB1 and TB2 tubes), as well as between the patients and the control subjects. ROC curves were drawn, and the AUCs were calculated. RESULTS: Five cytokines, i.e., IL-2, IL-6, IL-8, IP-10 and MIP-1ß, produced by human blood cells in three independent tubes containing different tuberculosis antigens were higher in the 3 G Ag tube compared to both the TB1 and TB2 tubes. Further, when the TB1 and TB2 tubes were compared, TB2 showed greater production of only PDGF-BB, and less production of IL-6 and TNF-α. For diagnosing active tuberculosis, the levels of IP-10 were superior to the level of IFN-γ based on showing a larger AUC for ROC curves in our present study setting. Finally, the levels of IFN-γ, IL-1RA, IL-2, IP-10, MCP-1 and MIP-1ß were distinctly different between the active tuberculosis patients and healthy controls. CONCLUSIONS: In summary, there was no cytokine that was higher in the tubes of QFT-plus compared to the tube of QFT-3 G, suggesting inferiority of QFT-plus antigens to 3 G Ag in terms of elicitation of cytokine production. Our results also suggest the usefulness of cytokines that showed a significant difference between the active tuberculosis patients and the healthy controls-namely, IFN-γ, IL-1RA, IL-2, IP-10, MCP-1 and MIP-1ß-for diagnosing tuberculosis, but the roles of these cytokines in the pathogenesis of tuberculosis need to be elucidated (UMIN000035253).

Immunogenicity and safety after the third vaccination with the 23-valent pneumococcal polysaccharide vaccine in elderly patients with chronic lung disease.

An observational study to assess immunogenicity before and after the first, second, and third vaccinations with the 23-valent pneumococcal polysaccharide vaccine in a cohort of 16 elderly patients with chronic lung diseases was conducted. The safety of this vaccine was also compared between the first, second, and third vaccinations. Serotype-specific immunoglobulin G (IgG) and the opsonization index (OI) for serotypes 6B, 14, 19F, and 23F were analyzed, and adverse local and systemic reactions were compared. The levels of serotype-specific IgG and OI increased significantly 1 month after the first, second, and third vaccinations. Peak IgG levels were higher after the third vaccination than after the second vaccination, but the levels of serotypes 6B, 14, and 19F were not higher than after the first vaccination. Serotype-specific OIs did not differ after the third vaccination compared with the first and second vaccinations. The level of serotype-specific IgG required for killing 50% of bacteria decreased significantly 1 month after the second vaccination. This level was slightly elevated immediately before the third vaccination but decreased after the third vaccination. Although self-limited local and systemic reactions were more frequent after the second and third vaccinations than after the first vaccination, no serious systemic reactions were seen after any vaccination. These data suggest that sustained functional serotype-specific IgG is produced after the first, second, and third vaccinations and they confirm the safety of the second and third vaccinations in elderly people with chronic lung disease.

Patency Capsule Aspiration.

A 77-year-old man with anemia who had undergone 2 abdominal surgeries for colon and gastric cancer experienced dyspnea after swallowing a patency capsule before endoscopy for investigating the cause of anemia. Chest radiography and computed tomography revealed that the patency capsule was located within the bronchus intermedius. It was successfully removed by flexible bronchoscopy. The balloon was placed over the capsule and inflated. Subsequently, the catheter was pulled, while thus dragging the capsule with it and preventing its destruction. In cases of patency capsule aspiration, the capsule must be removed without deformity, before it causes inflammation by releasing barium into the airway.

Species identification, antifungal susceptibility, and clinical feature association of Aspergillus section Nigri isolates from the lower respiratory tract.

Species of Aspergillus section Nigri are generally identified by molecular genetics approaches, whereas in clinical practice, they are classified as A. niger by their morphological characteristics. This study aimed to investigate whether the species of Aspergillus section Nigri isolated from the respiratory tract vary depending on clinical diagnosis. Forty-four Aspergillus section Nigri isolates isolated from the lower respiratory tracts of 43 patients were collected from February 2012 to January 2017 at the National Hospital Organization (NHO) Tokyo National Hospital. Species identification was carried out based on ß-tubulin gene analysis. Drug susceptibility tests were performed according to the Clinical and Laboratory Standards Institute (CLSI) M38 3rd edition, and the clinical characteristics were retrospectively reviewed. A. welwitschiae was isolated most frequently, followed by A. tubingensis. More than half of the A. tubingensis isolates exhibited low susceptibility to azoles in contrast to only one A. welwitschiae isolate. Approximately three quarters of the patients from whom A. welwitschiae was isolated were diagnosed with colonization, whereas more than half the patients from whom A. tubingensis was isolated were diagnosed with chronic pulmonary aspergillosis (CPA). More attention needs to be given to the drug choice for patients with CPA with Aspergillus section Nigri infection because A. tubingensis, which was found to be frequently azole-resistant, was the most prevalent in these patients.

Ten Cases of Intestinal Tuberculosis Which Were Initially Misdiagnosed as Inflammatory Bowel Disease.

Objective Intestinal tuberculosis (ITB) and inflammatory bowel disease (IBD) frequently present with similar clinical, endoscopic and pathological features, therefore it is difficult to differentiate between them. The aim of this study was to elucidate the diagnostic delay and prognosis of ITB cases, initially misdiagnosed as IBD. Methods ITB cases were selected from the hospitalized patient list between April 2004 and March 2017 in a tuberculosis center in Japan. We retrospectively evaluated the initial diagnosis, clinical characteristics, endoscopic and pathological findings, bacterial examinations, treatment and prognosis. Results Among 66 ITB patients, ten patients were initially misdiagnosed as IBD. Seven patients were male and the median age was 60.5 years (23-74 years). After the diagnosis of IBD, all the patients were treated with mesalazine, in addition to corticosteroids in two patients and sequential azathioprine and infliximab in one. The median duration of diagnostic delay was 5.5 months (range 0.5-17 months). Eight patients had active pulmonary tuberculosis at the diagnosis of ITB. Acid-fast bacilli were confirmed in four of seven patients by reevaluation of the pathological specimens at the IBD diagnosis. Two patients needed intestinal resection and one with erroneous corticosteroid use for IBD died due to respiratory failure in spite of receiving appropriate treatment for tuberculosis. Conclusion ITB patients were frequently misdiagnosed and treated as IBD, thus resulting in a poor clinical outcome even after finally making a correct diagnosis and administering appropriate treatment. On diagnosis of IBD and/or treatment failure, chest radiograph and acid-fast bacilli of the pathological specimens should be carefully evaluated in order to rule out tuberculosis.

Exacerbation of chronic pulmonary aspergillosis was associated with a high rebleeding rate after bronchial artery embolization.

BACKGROUND: Hemoptysis is a common symptom associated with chronic pulmonary aspergillosis (CPA). While surgery is the primary choice to manage hemoptysis, it is often avoided because patients with CPA are more likely to have complications such as respiratory insufficiency and low pulmonary function. Bronchial artery embolization (BAE) may be considered one of the treatments of massive and persistent hemoptysis for such patients. METHODS: We retrospectively reviewed medical records of 41 patients, admitted to National Hospital Organization Tokyo National Hospital, Tokyo, Japan with hemoptysis arising from CPA between January 2011 to December 2016, who were considered inoperable and had undergone BAE. RESULTS: Out of the 41 cases analyzed in this study, 21 (51.2%) developed rebleeding after BAE within the mean follow-up duration of 24 months. The non-rebleeding rate of patients after BAE was 92.7% within a month and 65.8% within a year. Patients who developed rebleeding had significantly more non-bronchial systemic arteries responsible for the bleeding compared with patients who did not develop rebleeding (mean of 2.55 vs. 4.86, respectively, P = 0.011). Patients with stable or improved radiological findings demonstrated significantly lower rebleeding rates than those with radiological deterioration (P < 0.001). The non-rebleeding patients had significantly better survival than those with rebleeding (79.7% vs. 39.9% over 5 years, P = 0.046). CONCLUSIONS: Bronchial artery embolization was effective in controlling hemoptysis in patients with CPA, especially those who could not undergo surgical resection. However, disease control of CPA was important to prevent rebleeding over the long term and to improve survival after BAE.

Clinical Features and Prognosis of Nontuberculous Mycobacterial Pleuritis.

BACKGROUND: While nontuberculous mycobacterial (NTM) pleuritis rarely complicates pulmonary NTM infection, high mortality has been reported in case reports and small studies. OBJECTIVES: The purpose of this study was to clarify the clinical features and treatment outcomes of pulmonary NTM infection cases accompanied by NTM pleuritis. METHODS: Medical records of 1,044 patients with pulmonary NTM disease were retrospectively reviewed to select patients complicated by NTM-proven pleuritis. We investigated clinical characteristics, pathogens, pleural effusion examinations, radiographic findings, treatments, and clinical course of the NTM pleuritis patients. RESULTS: Among 1,044 cases with pulmonary NTM, NTM pleuritis occurred in 15 cases (1.4%). The mean age was 69 years with a performance status of mostly 2 or better (80.0%), and 6 cases (40.0%) were complicated by pneumothorax. Subpleural cavities were radiologically detected in 11 cases (73.3%), and extrapulmonary air-fluid level was detected in 14 cases (93.3%). Eleven patients were treated with combinations of 2-4 antimycobacterial drugs, including clarithromycin, and 2 patients were treated with isoniazid, rifampicin, and ethambutol. Chest tube drainage was performed in 11 cases, and surgical approach was added in 6 cases. The pleural effusion of 2 patients treated with only antimycobacterial medications gradually deteriorated. Two patients died from NTM pleuritis, and 1 patient died from pneumonitis during a mean of 1.8 years of follow-up. CONCLUSIONS: Comorbid NTM pleuritis was difficult to treat by medical therapy alone and resulted in a poor prognosis. In addition to antimycobacterial agents, chest tube drainage and surgical procedures in the early stages should be considered to treat NTM pleuritis.