Nationwide survey in Japan of the causative diseases of bloody sputum and hemoptysis in departments of respiratory medicine at university hospitals and core hospitals.

BACKGROUND: The Guidelines for the Management of Cough and Sputum (2019) of the Japanese Respiratory Society (JRS) were the first internationally published guidelines for the management of sputum. However, the data used to determine the causative diseases of bloody sputum and hemoptysis in these guidelines were not obtained in Japan. METHODS: A retrospective analysis was performed using the clinical information of patients with bloody sputum or hemoptysis who visited the department of respiratory medicine at a university or core hospital in Japan. RESULTS: Included in the study were 556 patients (median age, 73 years; age range, 21-98 years; 302 males (54.3%)). The main causative diseases were bronchiectasis (102 patients (18.3%)), lung cancer (97 patients (17.4%)), and non-tuberculous mycobacterial disease (89 patients (16%)). Sex and age differences were observed in the frequency of causative diseases of bloody sputum and hemoptysis. The most common cause was lung cancer in males (26%), bronchiectasis in females (29%), lung cancer in patients aged <65 years (19%), and bronchiectasis in those aged >65 years (20%). CONCLUSIONS: The present study is the first to investigate the causative diseases of bloody sputum and hemoptysis using data obtained in Japan. When investigating the causative diseases of bloody sputum and hemoptysis, it is important to take the sex and age of the patients into account.

Risk factor of non-tuberculous Mycobacterium infection in patients with rheumatoid arthritis and other autoimmune diseases receiving biologic agents: A multicenter retrospective study.

BACKGROUND: Evidence regarding the association of the usage of biologic agents (Etanercept, Tocilizumab, adalimumab and so on), such as anti-tumor necrosis factor α, with the incidence and risk factors of non-tuberculous Mycobacteria (NTM) infection is limited. Therefore, this study aimed to investigate the incidence and risk factors of NTM and their associations with biologic agents' usage, and also investigated the potential of Mycobacterium avium complex (MAC) antibodies as a predictor of NTM infection development. METHODS: This retrospective study included 672 patients with autoimmune diseases from four hospitals in Nagasaki, Japan, from January 1, 2011, to June 30, 2019, who fulfilled the inclusion criteria. RESULTS: Of the 672 patients, 9 (1.3%) developed complicated NTM infection, including two with disseminated infection, after the introduction of biologic agents. Of the nine patients, two died due to NTM infection but none tested positive for MAC antibodies prior to initiation of biologic agents. The mortality rate was higher in patients complicated with NTM than without NTM (22.2% vs 2.6%, P = 0.024). The corticosteroids dosage at the time of initiating the biologic agents was significantly higher in the NTM group than in the non-NTM group (median, 17 mg vs 3 mg, P = 0.0038). CONCLUSION: In the patients undergoing therapy with biologic agents, although NTM complication was rare, it could be fatal. In particular, for patients on a relatively high dose corticosteroids, careful observation is essential for identifying NTM complication, even if the MAC antibody test is negative.

High attenuation mucus in bronchi with allergic bronchopulmonary mycosis.

BACKGROUND: High-attenuation mucus (HAM) is a specific manifestation of allergic bronchopulmonary mycosis (ABPM) on chest computed tomography (CT). OBJECTIVES: To compare the diagnostic accuracy of the two definitions of HAM and to clarify the clinical and radiographic characteristics of HAM-positive and HAM-negative ABPM. METHODS: CT images at the diagnosis of ABPM using Asano's criteria were retrospectively analysed. In Study #1, radiographic data obtained using the same CT apparatus in a single institute were analysed to determine the agreement between the two definitions of HAM: a mucus plug that is visually denser than the paraspinal muscles or that with a radiodensity ≥70 Hounsfield units. In Study #2, HAM was diagnosed by comparison with the paraspinal muscles in patients with ABPM reporting to 14 medical institutes in Japan. RESULTS: In Study #1, 93 mucus plugs from 26 patients were analysed. A substantial agreement for HAM diagnosis was observed between the two methods, with a κ coefficient of 0.72. In Study #2, 60 cases of ABPM were analysed; mucus plugs were present in all cases and HAM was diagnosed in 45 (75%) cases. The median A. fumigatus-specific IgE titre was significantly lower in HAM-positive patients than in HAM-negative patients (2.5 vs. 24.3 UA /mL, p = .004). Nodular shadows were observed more frequently in the airways distal to HAM than in those distal to non-HAM mucus plugs (59% vs. 32%, p < .001). CONCLUSION: In conclusion, agreement between the two methods to diagnose HAM was substantial. HAM was associated with some immunological and radiographic characteristics, including lower levels of sensitization to A. fumigatus and the presence of distal airway lesions.

Efficacy and safety of macrolide therapy for adult asthma: A systematic review and meta-analysis.

BACKGROUND: The evidence for macrolide therapy in adult asthma is not properly established and remains controversial. We conducted a systematic review and meta-analysis to examine the efficacy and safety of macrolide therapy for adult asthma. METHODS: We searched randomized controlled trials from MEDLINE via the PubMed, CENTRAL, and Ichushi Web databases. The primary outcome was asthma exacerbation. The secondary outcomes were serious adverse events (including mortality), asthma-related quality of life (symptom scales, Asthma Control Questionnaire, and Asthma Quality of Life Questionnaire), rescue medication (puffs/day), respiratory function (morning peak expiratory flow, evening peak flow, and forced expiratory volume in 1 s), bronchial hyperresponsiveness, and minimum oral corticosteroid dose. Of the 805 studies, we selected seven studies for the meta-analysis, which was conducted using a random-effects model. SYSTEMATIC REVIEW REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (UMIN000050824). RESULTS: No significant difference between macrolide and placebo for asthma exacerbations was observed (risk ratio 0.71, 95 % confidence interval [CI] 0.46-1.09; p = 0.12). Macrolide therapy for adult asthma showed a significant improvement in rescue medication with short-acting beta-agonists (mean difference -0.41, 95 % CI -0.78 to -0.04; p = 0.03). Macrolide therapy did not show more serious adverse events (odd ratio 0.61, 95 % CI 0.34-1.10; p = 0.10) than those with placebo. The other secondary outcomes were not significantly different between the macrolide and placebo groups. CONCLUSIONS: Macrolide therapy for adult asthma may be more effective than placebo and could be a treatment option.

Clinical characteristics of allergic bronchopulmonary mycosis caused by Schizophyllum commune.

BACKGROUND: Allergic bronchopulmonary mycosis (ABPM) is an allergic disease caused by type I and type III hypersensitivity to environmental fungi. Schizophyllum commune, a basidiomycete fungus, is one of the most common fungi that causes non-Aspergillus ABPM. OBJECTIVE: Herein, we attempted to clarify the clinical characteristics of ABPM caused by S. commune (ABPM-Sc) compared with those of allergic bronchopulmonary aspergillosis (ABPA). METHODS: Patients with ABPM-Sc or ABPA were recruited from a nationwide survey in Japan, a multicenter cohort, and a fungal database at the Medical Mycology Research Center of Chiba University. The definition of culture-positive ABPM-Sc/ABPA is as follows: (1) fulfills five or more of the 10 diagnostic criteria for ABPM proposed by Asano et al., and (2) positive culture of S. commune/Aspergillus spp. in sputum, bronchial lavage fluid, or mucus plugs in the bronchi. RESULTS: Thirty patients with ABPM-Sc and 46 with ABPA were recruited. Patients with ABPM-Sc exhibited less severe asthma and presented with better pulmonary function than those with ABPA (p = 0.008-0.03). Central bronchiectasis was more common in ABPM-Sc than that in ABPA, whereas peripheral lung lesions, including infiltrates/ground-glass opacities or fibrotic/cystic changes, were less frequent in ABPM-Sc. Aspergillus fumigatus-specific immunoglobulin (Ig)E was negative in 10 patients (34%) with ABPM-Sc, who demonstrated a lower prevalence of asthma and levels of total serum IgE than those with ABPM-Sc positive for A. fumigatus-specific IgE or ABPA. CONCLUSIONS: Clinical characteristics of ABPM-Sc, especially those negative for A. fumigatus-specific IgE, differed from those of ABPA.

Lung Involvement in Adult T-Cell Lymphoma Diagnosed Using Bronchoscopic Cryobiopsy: A Case Report and Review of the Literature.

The diagnosis of pulmonary lymphoma using small tissue samples is difficult and often requires surgical procedures; thus, a less invasive sampling method is desirable. Moreover, pulmonary involvement in adult T-cell lymphoma (ATL) is often difficult to diagnose, especially in cases without characteristic flower cells. Here, we present the case of a 78-year-old man, in whom pathological examination of the transbronchial lung biopsy (TBLB) specimen did not reveal malignant findings; therefore, transbronchial lung cryobiopsy (TBLC) in combination with endobronchial ultrasonography (EBUS) was used to diagnose ATL based on the pathological findings. A literature review identified 18 cases of pulmonary lymphomas diagnosed using TBLC. Among the 19 cases, including our own, 16 cases were of B-cell lymphoma (84.2%), and the present case is the first case of ATL diagnosed using TBLC. Eighty percent of the cases underwent a biopsy (more than two samples) of the middle or lower lobe and were diagnosed without major complications. EBUS was used with TBLC in three cases to identify the location of the pulmonary lesions. In the present case, EBUS was also useful for avoiding vascular biopsy. Although large-scale prospective studies are required to establish precise guidelines for diagnosing pulmonary lymphomas using TBLC, our case report and review contributes to a deeper understanding of the diagnosis of rare diseases.

Pulmonary Langerhans cell histiocytosis diagnosed using transbronchial lung cryobiopsy: A case report.

A 63-year-old Japanese woman with multiple cysts in both lungs on chest computed tomography (CT) was referred to our hospital after a thorough examination, including a transbronchial lung biopsy (TBLB), failed to provide a diagnosis. Based on the findings on chest CT and pathological examination of the bronchoalveolar lavage fluid and transbronchial lung cryobiopsy (TBLC) specimen, the patient was diagnosed with pulmonary Langerhans cell histiocytosis (PLCH). TBLC may replace TBLB as the main diagnostic technique for PLCH, although further studies are required to determine the usefulness of TBLC for the diagnosis of PLCH.

Serum Cytokine Changes in a Patient with Chronic Pulmonary Aspergillosis Overlapping with Allergic Bronchopulmonary Aspergillosis: A Case Report.

Allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA) are diseases caused by Aspergillus infection, and CPA can develop from ABPA in some cases. We herein report a patient with CPA overlapping with ABPA. Serum cytokine levels were evaluated at 4 time points: the ABPA diagnosis, CPA diagnosis, 6 months after the start of voriconazole (VRCZ), and 12 months after re-administration of VRCZ. Interleukin (IL)-13 levels decreased upon glucocorticoid treatment, whereas IL-25 and IL-33 levels decreased rapidly with the initiation of antifungals. Early antifungal therapy may be important to control disease progression and prevent CPA overlap.

Disseminated Mycobacterium genavense Infection Mimicking Sarcoidosis: A Case Report and Review of Literature on Japanese Patients.

Sarcoidosis is a systemic inflammatory disease characterized by noncaseating epithelioid cell granulomas. However, certain infections can exhibit similar histological findings. We present a case of a 69-year-old man who was initially diagnosed with sarcoidosis and later was confirmed, through 16S rRNA sequencing, to have disseminated Mycobacterium genavense infection. Acid-fast bacteria were detected in the bone marrow biopsy using Ziehl-Neelsen staining, but routine clinical tests did not provide a definitive diagnosis. The patient tested negative for HIV, anti-interferon-gamma antibodies, and genetic immunodeficiency disorders. He was treated with multiple drugs, including aminoglycosides and macrolides, but showed no improvement in fever and pancytopenia. However, these clinical signs responded favorably to steroid therapy. We reviewed 17 Japanese cases of M. genavense infection. All cases were in males; 7/17 (41%) were HIV-negative; and 12/17 (71%) had a decreased CD4 count. Genetic analysis confirmed M. genavense isolation, and macrolides were used universally. Mycobacterium genavense infection is challenging to identify and mimics other systemic inflammatory diseases such as sarcoidosis. There are no standard treatment protocols. Our case report and Japanese case review contribute to understanding this rare disease.

Drug-induced interstitial lung disease caused by olaparib: three case reports and review of the Japanese Adverse Drug Event Report database and literature.

BACKGROUND: Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, has demonstrated effectiveness in treating ovarian, breast, and other cancers, particularly those with specific molecular subtypes including, but not limited to, BRCA1/2 mutations. Consequently, its utilization is expected to increase in the future. For this reason, it is important to acknowledge the potential for adverse events associated with olaparib, including the relatively rare but significant risk of drug-induced interstitial lung disease (DIILD). Since DIILD can lead to fatal outcomes, its early detection is crucial. The dissemination of knowledge regarding DIILD can be facilitated through case reports; however, specific reports of DIILD caused by olaparib have only been published in Japanese. To the best of our knowledge, this is the first report in English of our experience with three cases of DIILD caused by olaparib. CASE PRESENTATION: Cases 1, 2, and 3 involved Japanese women with ovarian cancer who had been receiving olaparib at a dose of 600 mg/day. Case 1, a 72-year-old woman who had been on olaparib for 4 months, and case 2, a 51-year-old woman who had been on olaparib for 8 months, reported fever and general malaise. Chest computed tomography (CT) revealed pale ground glass opacity (GGO) similar to hypersensitivity pneumonitis. The severity grade was 2 in both cases. Case 3, a 78-year-old woman who had been on olaparib for 3 weeks, presented with cough and reported dyspnea on exertion. Chest CT revealed non-specific interstitial pneumonia and organizing pneumonia-like shadows. The severity grade was 4. Olaparib was discontinued in all cases. Case 1 received 0.6 mg/kg of prednisolone due to mild hypoxia, while prednisolone was not administered in case 2 due to the absence of hypoxia. Case 3 received steroid pulse therapy due to severe hypoxia. Olaparib administration was not resumed in any patient. CONCLUSION: DIILD caused by olaparib in Japan, including the present three cases, commonly presents with GGO, similar to hypersensitivity pneumonitis on chest CT. The prognosis for the majority of patients is favorable; however, there have been instances of severe cases. Early recognition of drug-induced lung injury and further accumulation of cases is important.

Allergic bronchopulmonary aspergillosis with atopic, nonatopic, and sans asthma-Factor analysis.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) develops in the presence or absence of asthma, either atopic or nonatopic. We have tried to explore the essential components in the pathogenesis of the disease, which are either consistent and variable according to the presence and type of asthma. METHODS: Non-cystic fibrosis ABPA cases satisfying Asano's criteria were extracted from a prospective registry of ABPA and related diseases in Japan between 2013 and 2023. According to the type of preceding asthma, ABPA was classified into three groups: ABPA sans asthma (no preceding asthma), ABPA with atopic asthma, and ABPA with nonatopic asthma. Exploratory and confirmatory factor analyses were performed to identify the components that determined the clinical characteristics of ABPA. RESULTS: Among 106 cases of ABPA, 25 patients (24%) had ABPA sans asthma, whereas 57 (54%) and 24 (23%) had ABPA with atopic and nonatopic asthma, respectively. Factor analysis identified three components: allergic, eosinophilic, and fungal. Patients with atopic asthma showed the highest scores for the allergic component (p < .001), defined by total and allergen-specific IgE titers and lung opacities, and the lowest scores for the fungal component defined by the presence of specific precipitin/IgG or positive culture for A. fumigatus. Eosinophilic components, including peripheral blood eosinophil counts and presence of mucus plugs/high attenuation mucus in the bronchi, were consistent among the three groups. CONCLUSION: The eosinophilic component of ABPA is considered as the cardinal feature of ABPA regardless of the presence of preceding asthma or atopic predisposition.

Impact of Administering Intravenous Azithromycin within 7 Days of Hospitalization for Influenza Virus Pneumonia: A Propensity Score Analysis Using a Nationwide Administrative Database.

The potential antimicrobial and anti-inflammatory effectiveness of azithromycin against severe influenza is yet unclear. We retrospectively investigated the effect of intravenous azithromycin administration within 7 days of hospitalization in patients with influenza virus pneumonia and respiratory failure. Using Japan's national administrative database, we enrolled and classified 5066 patients with influenza virus pneumonia into severe, moderate, and mild groups based on their respiratory status within 7 days of hospitalization. The primary endpoints were total, 30-day, and 90-day mortality rates. The secondary endpoints were the duration of intensive-care unit management, invasive mechanical ventilation, and hospital stay. The inverse probability of the treatment weighting method with estimated propensity scores was used to minimize data collection bias. Use of intravenous azithromycin was proportional to the severity of respiratory failure (mild: 1.0%, moderate: 3.1%, severe: 14.8%). In the severe group, the 30-day mortality rate was significantly lower with azithromycin (26.49% vs. 36.65%, p = 0.038). In the moderate group, the mean duration of invasive mechanical ventilation after day 8 was shorter with azithromycin; there were no significant differences in other endpoints between the severe and moderate groups. These results suggest that intravenous azithromycin has favorable effects in patients with influenza virus pneumonia using mechanical ventilation or oxygen.

Genetic profile of thymic epithelial tumors in the Japanese population: an exploratory study examining potential therapeutic targets.

Background: Thymic epithelial tumors (TETs) are prone to developing in East Asian populations. However, little is known about the genomic profile of TETs in East Asian populations, and the genomic aberrations in TETs have not yet been fully clarified. Thus, molecular targeted therapies for patients with TETs have not been established. This prospective study was conducted to explore the genetic abnormalities of surgically resected TETs in a Japanese cohort and to identify clues for carcinogenesis and potential therapeutic targets in TETs. Methods: Genetic profiles of TETs were investigated using fresh-frozen specimens resected from operable cases with TETs. DNA sequencing was performed using a next-generation sequencing (NGS) gene panel test with Ion Reporter™ and CLC Genomics Workbench 11.0. The mutation sites were further confirmed by Sanger sequencing, digital droplet polymerase chain reaction (ddPCR), and TA cloning for validation. Results: Among 43 patients diagnosed with anterior mediastinal tumors between January 2013 and March 2019, NGS and validation analyses were performed in 31 patients [29 thymomas and two thymic cancers (TCs)] who met the study criteria. Of these, 12 cases of thymoma types A, AB, B1, and B2 harbored the general transcription factor 2-I (GTF2I) mutation (L424H). Conversely, the mutation was not detected in type B3 thymoma or TC, suggesting that the GTF2I mutation existed in indolent types of TETs. Rat sarcoma viral oncogene (RAS) mutations were detected in three cases [Harvey RAS (HRAS) in two cases of type AB thymoma and neuroblastoma RAS (NRAS)] in one case of type B1 thymoma), and additional sex combs like 1 (ASXL1) mutation was present in one case of TC. All RAS mutations were observed in GTF2I-mutated cases. Conclusions: The GTF2I mutation (L424H) is the most frequently occurring mutation in the limited histology of thymoma, consistent with those in the non-Asian population. HRAS and NRAS mutations co-occurred in cases harboring the GTF2I mutation. These findings suggest that the existence of the GTF2I mutation might be related to indolent types of TETs, and RAS mutations could be candidates as therapeutic targets in TETs.

A case of drug-induced organizing pneumonia caused by amikacin liposome inhalation suspension.

Inhaled liposomal antimicrobials are known to cause hypersensitivity pneumonitis. Amikacin liposome inhalation suspension (ALIS) is a promising novel antimicrobial agent against refractory Mycobacterium avium complex infections. The frequency of drug-induced lung injury caused by ALIS is relatively high. To date, no reports of ALIS-induced organizing pneumonia diagnosed by bronchoscopy are available. We report a case of a 74-year-old female patient presenting with non-tuberculous mycobacterial pulmonary disease (NTM-PD). She was treated with ALIS for refractory NTM-PD. Fifty-nine days after starting ALIS, the patient developed a cough, and her chest radiographs indicated deterioration. She was diagnosed with organizing pneumonia based on pathological findings of the lung tissues obtained by bronchoscopy. After switching from ALIS to amikacin infusion, her organizing pneumonia improved. It is difficult to distinguish between organizing pneumonia and an exacerbation of NTM-PD based on chest radiography alone. Therefore, it is essential to perform an active bronchoscopy for diagnosis.

Pulmonary phaeohyphomycosis due to Exophiala dermatitidis in a patient with pulmonary non-tuberculous mycobacterial infection.

A 65-year-old Japanese woman repeatedly withdrew and resumed antibiotics against pulmonary non-tuberculous mycobacterial infection caused by Mycobacterium intracellulare for more than 10 years. Although she continued to take medications, her respiratory symptoms and chest computed tomography indicated an enlarged infiltrative shadow in the lingular segment of the left lung that gradually worsened over the course of a year or more. Bronchoscopy was performed and mycobacterial culture of the bronchial lavage fluid was negative, whereas Exophiala dermatitidis was detected. After administration of oral voriconazole was initiated, the productive cough and infiltrative shadow resolved. There are no characteristic physical or imaging findings of E. dermatitidis, and it often mimics other chronic respiratory infections. Thus, when confronting refractory non-tuberculous mycobacterial cases, it might be better to assume other pathogenic microorganisms, including E. dermatitidis, and actively perform bronchoscopy.

Pulmonary Langerhans Cell Histiocytosis That Progressed from a Single-system to a Multisystem Form despite Smoking Cessation.

A 36-year-old Japanese man presented with cavities and nodular shadows in the lower lobes of his lungs and osteolytic lesions in the thoracic spine. He was diagnosed with multisystem Langerhans cell histiocytosis (LCH). Three years earlier, he had been noted to have small cavities and granular lesions noted in the upper lobes of his lungs, which later improved with smoking cessation. It was likely that his single-system pulmonary LCH (PLCH) progressed to multisystem LCH despite smoking cessation. Relapse or progression may occur in cases where PLCH lesions improve after smoking cessation. Thus, close follow-up is vital.

Pulmonary and Intestinal Involvement in a Patient with Myeloperoxidase-specific Antineutrophil Cytoplasmic Antibody-positive Hermansky-Pudlak Syndrome.

A 26-year-old Japanese woman was admitted with a 1-month history of diarrhea, a high fever for a few days, and exacerbation of dyspnea. She was treated with an antifibrotic drug and long-term oxygen therapy for Hermansky-Pudlak syndrome-related pulmonary fibrosis. New ground-glass attenuation appeared on chest computed tomography (CT), and a colon biopsy showed an inflammatory cell accumulation with a high titer of myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (ANCA). Systemic inflammation related to MPO-ANCA titer elevation was suspected. Steroid pulse therapy and intravenous cyclophosphamide improved chest CT findings and diarrhea. Therefore, immunosuppressant treatment should be considered for systemic inflammation related to MPO-ANCA.

Serum Cytokines Usefulness for Understanding the Pathology in Allergic Bronchopulmonary Aspergillosis and Chronic Pulmonary Aspergillosis.

Allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA) are important fungal infections caused by Aspergillus species. An overlap of ABPA and CPA has been reported; therefore, it is critical to determine whether the main pathology is ABPA or CPA and whether antifungals are required. In this study, we investigated whether the serum cytokine profile is useful for understanding the pathology and for differentiating between these diseases. We compared the various serum cytokine levels among healthy subjects and patients diagnosed with asthma, ABPA, or CPA at Nagasaki University Hospital between January 2003 and December 2018. In total, 14 healthy subjects, 19 patients with asthma, 11 with ABPA, and 10 with CPA were enrolled. Interleukin (IL) -5 levels were significantly higher in patients with ABPA than in those with CPA, and IL-33 and tumor necrosis factor (TNF) levels were significantly higher in patients with CPA than in those with asthma (p < 0.05, Dunn's multiple comparison test). The sensitivity and specificity of the IL-10/IL-5 ratio (cutoff index 2.47) for diagnosing CPA were 70% and 100%, respectively. The serum cytokine profile is useful in understanding the pathology of ABPA and CPA, and the IL-10/IL-5 ratio may be a novel supplemental biomarker for indicating the pathology of CPA.

Interstitial Pneumonia with HLA-B54 Antigen that Responded Well to Erythromycin.

A 65-year-old Japanese man with interstitial pneumonia demonstrated honeycomb lung with thickened walls on chest high-resolution computed tomography (HRCT) and predominance of neutrophils in the cell fraction of the bronchoalveolar lavage fluid. Although there were no centrilobular nodular or branching shadows on chest HRCT suggestive of diffuse panbronchiolitis, he exhibited sinusitis and had the human leukocyte antigen (HLA)-B54 antigen. With long-term macrolide therapy, the cough and sputum production markedly improved, wall thickening of the honeycomb lung on chest HRCT decreased, and the forced vital capacity increased. Confirming the presence of HLA-B54 antigen may help determine the indication for long-term macrolide therapy in interstitial pneumonia patients.

Autoimmune pulmonary alveolar proteinosis exacerbated by steroid therapy due to misdiagnosis as anti-aminoacyl-tRNA synthetase (ARS) antibody positive- interstitial pneumonia: a case report.

BACKGROUND: Anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are myositis-specific autoantibodies that have been identified in a subset of patients with interstitial pneumonia who do not present with dermatomyositis or polymyositis. Anti-ARS antibody-positive interstitial pneumonia is commonly treated with steroids or immunosuppressive agents and is usually responsive to these therapies. Here, we present in detail a case in which respiratory failure of a patient diagnosed with anti-ARS antibody-positive interstitial pneumonia was exacerbated by treatment with steroids and immunosuppressive agents. Further examination revealed misdiagnosis of this patient and a subsequent diagnosis of autoimmune pulmonary alveolar proteinosis. CASE PRESENTATION: A 66-year-old man presented to the hospital with dyspnea on exertion, which resulted in the detection of interstitial pneumonia. Serum anti-ARS antibodies were detected; however, there were no other findings suggestive of myositis. Pulmonary alveolar proteinosis (PAP) was suspected based on the marked increase in serum KL-6 and chest computed tomography findings. The bronchoalveolar lavage revealed no milky changes in the lavage fluid. After treatment with steroids and initiation of immunosuppressive agents for anti-ARS antibody-positive interstitial pneumonia, respiratory failure and chest imaging findings showed worsening of the condition. Bronchoscopy was repeated, and milk-like alveolar lavage fluid was collected; serum anti-granulocyte macrophage colony-stimulating factor antibody was identified. Steroids and immunosuppressive agents were gradually tapered and discontinued, and the patient's condition stabilized after repeated alveolar lavage under general anesthesia. CONCLUSION: Due to similar presentation, PAP can be misdiagnosed as interstitial pneumonia. If pulmonary lesions due to interstitial pneumonia are exacerbated by immunosuppressive treatment, physicians should reconsider the diagnosis and include PAP in the differential diagnosis.