Nonfibrotic (cellular) hypersensitivity pneumonitis with and without slight lung distortion.

BACKGROUND: According to international diagnostic guidelines for hypersensitivity pneumonitis (HP), cases with both nonfibrotic and fibrotic lesions are classified by the predominant feature. Therefore, some cases with nonfibrotic HP, have inflammatory lesions alone, while others have a mixture of fibrosis and inflammation. We investigated the impact of slight fibrotic lesions in nonfibrotic HP. METHODS: This retrospective study included nonfibrotic HP cases with <10% of lung distortion on high-resolution CT. We divided the cases into two groups: those with pure ground glass opacities (GGOs) without lung distortion and those with slight lung distortion of <10%. RESULTS: In this study, 37 cases were included. The mean baseline forced vital capacity (FVC) was 109% in the pure GGO group and 96% in the slight lung distortion group (p = 0.038). After 1 year, the reticular shadows appeared or increased more in the slight lung distortion group than in the pure GGO group (16% vs. 8%, p = 0.030). The time to medication initiation was significantly shorter in the slight lung distortion group than in the pure GGO group (p = 0.044). %FVC decreased by ≥ 5% from diagnosis in no cases with the pure GGO and in two cases with the slight lung distortion (-11.0% for 9.5 years and -10.7% for 1.3 years, respectively). CONCLUSIONS: The slight distortion group exhibited a higher rate of worsening and new appearance of reticular shadows after 1 year and a shorter time to first medication compared to the pure GGO group.

Usefulness of Transbronchial Lung Cryobiopsy When Starting Antifibrotic Treatment and Predicting Progressive Fibrosing Interstitial Lung Disease: Descriptive Research.

BACKGROUND: Although transbronchial lung cryobiopsy (TBLC) is widely used in diagnostic algorithms for various interstitial lung diseases (ILDs), its real-world utility in the therapeutic decision-making strategy for ILD patients remains unclear, in particular, when judging the time to start antifibrotic agents. METHODS: We analyzed medical records of 40 consecutive patients with idiopathic or fibrotic hypersensitivity pneumonitis who underwent TBLC. A TBLC-based usual interstitial pneumonia (UIP) score was used to assess three morphologic descriptors: patchy fibrosis, fibroblastic foci, and honeycombing. RESULTS: In our 40 patients with ILD, the most frequent radiological feature was indeterminate for UIP (45.0%). Final diagnosis included idiopathic pulmonary fibrosis (22.5%), fibrotic nonspecific interstitial pneumonia (5.0%), fibrotic hypersensitivity pneumonitis (35.0%), and unclassifiable ILD (37.5%). Linear mixed-effects analysis showed that declines in the slopes of %FVC and %DLCO in patients with TBLC-based UIP "Score ≥ 2" were significantly steeper than those of patients with "Score ≤ 1." During follow-up of patients with Score ≥ 2 (n = 24), more than half of them (n = 17) received an antifibrotic agent, with most patients (n = 13) receiving early administration of the antifibrotic agent within 6 months after the TBLC procedure. CONCLUSIONS: TBLC-based UIP Score ≥ 2 indicated the increased possibility of a progressive fibrosis course that may prove helpful in predicting progressive pulmonary fibrosis/progressive fibrosing ILD even if disease is temporarily stabilized due to anti-inflammatory agents. Patients may benefit from early introduction of antifibrotic agents by treating clinicians.

Proposed Clinical Algorithm for Pleuroparenchymal Fibroelastosis (PPFE).

Pleuroparenchymal fibroelastosis (PPFE) is characterized by fibrosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobes. As PPFE appears to occur in patients with heterogeneous etiologies, the disease course is thus also heterogenous, with some patients showing rapid progression while others have slow progression. Therefore, it is very difficult to predict prognosis with PPFE. Needless to say, this problematic matter has influenced the treatment strategy of PPFE patients. In fact, until now no evidence has been shown for use in creating an appropriate management algorithm for PPFE. We speculate that "uncoordinated breathing" is the most important reason for dyspnea in PPFE patients. Because monitoring of physique and not just pulmonary function and radiological evaluation is also very important, particularly in PPFE patients, this review focused on the characteristics of PPFE through an overview of previous studies in this field, and we proposed an algorithm as precision medicine based on the current evidence. Multiple views by the pulmonologist are needed to standardize a clinical algorithm that is necessary to correctly assess PPFE patients under the premise of maintenance of physique by providing appropriate nutritional care and pulmonary rehabilitation.

Longitudinal changes in serum immunoglobulin G testing in patients with fibrotic avian hypersensitivity pneumonitis.

BACKGROUND: Evaluation of the antigen responsible for fibrotic hypersensitivity pneumonitis (HP) is challenging. Serum immunoglobulin (Ig) G testing against HP-associated antigens is performed. Although single-serum IgG testing has been investigated, multiple-serum IgG testing has not yet been studied. METHODS: This study included patients who underwent histopathological examination and positive inhalation challenge test as well as those with moderate or high HP guideline confidence level. Serum IgG testing against pigeon serum was conducted twice using two methods: enzyme linked-immunosorbent assay (ELISA) and ImmunoCAP. The association between changes in serum IgG antibody titers and changes in forced vital capacity (FVC) and other parameters was investigated. RESULTS: In this study, 28 patients (mean age, 64.5 years; mean FVC, 85.3%) with fibrotic avian HP were selected, of whom 20 and 8 underwent surgical lung biopsy and transbronchial lung cryobiopsy, respectively. Of the 28 patients, 19 had been keeping birds for more than 6 months. A correlation was observed between the annual changes in serum IgG antibody titers by ELISA and changes in relative FVC (r = - 0.6221, p < 0.001). Furthermore, there was a correlation between the annual changes in serum IgG antibody titers by ImmunoCAP and changes in relative FVC (r = - 0.4302, p = 0.022). Multiple regression analysis revealed that the change in serum IgG antibody titers by both ELISA and ImmunoCAP also influenced the relative FVC change (p = 0.012 and p = 0.015, respectively). Moreover, 13 patients were given additional treatments between the first and second blood test; however, the additional treatment group was not significantly different in relative FVC change compared to the group with no additional treatment (p = 0.982). CONCLUSIONS: In patients with fibrotic avian HP, the annual changes in serum IgG testing were correlated with FVC changes, highlighting the importance of serum IgG testing over time.

Two cases of airway-centered fibroelastosis treated with an antifibrotic agent and corticosteroids.

Airway-centered fibroelastosis is characterized by peribronchovascular fibroelastosis, predominantly in the upper lobes, with little-to-no pleural involvement. In this study, we describe two cases of airway-centered fibroelastosis diagnosed based on radiological and pathological findings. The first case comprised a 44-year-old man whose forced vital capacity improved over three months following treatment with nintedanib. The second case involved a 50-year-old woman who was treated with oral corticosteroids but yielded an unfavorable outcome. An effective treatment for airway-centered fibroelastosis has not yet been identified; therefore, this study may help contribute to a more thorough discussion regarding treatment strategies for this disease.

Compatible with fibrotic hypersensitivity pneumonitis on high-resolution computed tomography: from the ATS/JRS/ALAT 2020 hypersensitivity pneumonitis guidelines.

Background: In compatible with fibrotic hypersensitivity pneumonitis (HP) of the computed tomography (CT) classification using the American Thoracic Society (ATS)/Japanese Respiratory Society (JRS)/Latin American Thoracic Association (ALAT) HP guidelines, the lung fibrosis pattern was classified as either a usual interstitial pneumonia (UIP) pattern or a diffuse ground-glass opacity (GGO) pattern with subtle fibrosis. We investigated whether patients with the same imaging classification had different disease progression. We also attempted to reclassify these patients using the CHEST HP guidelines. Methods: Patients with fibrotic HP who had compatible CT pattern in the ATS/JRS/ALAT classification were investigated retrospectively. Results: With 62 patients in the UIP pattern group and 25 patients in the diffuse GGO pattern group, 87 patients with fibrotic HP had compatible pattern on CT. Annual forced vital capacity changes in the UIP pattern group and diffuse GGO pattern group were -2.7% and +3.3% (P=0.004), respectively. The 5-year survival rates in the UIP pattern group and diffuse GGO pattern group were 86% and 100% (P=0.02). In UIP pattern group in the ATS/JRS/ALAT classification, 27% patients were classified as typical fibrotic HP pattern in the CHEST guidelines. In the diffuse GGO pattern group, 52% patients were classified as typical pattern of fibrotic HP. In the CHEST guidelines, more patients in the GGO pattern were classified as typical pattern compared with those in the UIP pattern (P=0.02). Conclusions: The two patterns in compatible with fibrotic HP of CT classification using the ATS/JRS/ALAT HP guidelines had different disease progression. Typical patterns were more frequent in the CHEST guidelines than the ATS/JRS/ALAT guidelines.

Body weight loss is a simple and useful indicator of prognosis and predictive tolerability in the first year of nintedanib therapy in patients with interstitial lung disease.

BACKGROUND: Nintedanib is generally safe and well tolerated and can improve prognosis in patients with various interstitial lung diseases (ILDs). Appropriate management of adverse events of nintedanib is important to ensure its long-term persistent use. Weight loss is a routinely assessed adverse event in clinical practice. This study aimed to elucidate whether body weight change in the first year of nintedanib therapy can indicate prognosis and predict tolerability in patients with ILD. METHODS: We analysed 245 consecutive ILD patients treated with nintedanib. We calculated the slope of body weight change using baseline weight and that recorded closest after the first year and then categorized percent change in body weight at this time. Significant weight loss was defined as that ≥5%. RESULTS: Subjects included 67 patients with idiopathic pulmonary fibrosis (IPF) and 76 with non-IPF progressive fibrosing-ILD including fibrotic hypersensitivity pneumonitis (n = 16), unclassifiable (n = 35), connective tissue disease-ILD (n = 21), and nonspecific interstitial pneumonia (n = 4). Older age, low body weight at initial examination, significant weight loss, and lower %FVC were significant predictors of discontinuation of nintedanib. Patients with weight loss ≥5% over the first year showed worse survival than those with weight loss <5% regardless of whether IPF existed or BMI indicated obesity. CONCLUSIONS: Careful monitoring of body weight change might suggest useful information for predicting long-term use of nintedanib and mortality risk in ILD patients treated with nintedanib. Appropriate body weight management is needed to prevent adverse events of nintedanib itself.

Drug-related pneumonitis caused by amikacin liposome inhalation suspension: One pathologically proven case and single-center experience.

Amikacin liposome inhalation suspension (ALIS) is known to cause drug-related pneumonitis, which has been described as "hypersensitivity pneumonitis (HP)". However, its clinical and pathological characteristics have never been reported. We retrospectively evaluated 18 patients treated with ALIS. Three (16.7%) patients developed HP-pattern pneumonitis on high-resolution computed tomography. Serum eosinophil counts were elevated up to above 1000/µL in these three patients, which decreased with ALIS discontinuation only. Of note, the specimen obtained by transbronchial lung cryobiopsy in one patient revealed a mild degree of lymphocyte and eosinophil infiltration. Rather, the findings of acute lung injury such as an edematous thickening of the alveolar walls, and an accumulation of foamy degenerative macrophages in the alveolar lumina was prominent. A pulmonary alveolar proteinosis reaction was also observed. HP-pattern pneumonitis due to ALIS may pathologically correspond to acute lung injury and a pulmonary alveolar proteinosis reaction despite increasing serum eosinophil counts.

Hypersensitivity pneumonitis with Paecilomyces as suspected inciting antigen.

A 73-year-old man visited our hospital for persistent cough. Chest high-resolution CT (HRCT) showed infiltration shadows in lower lobes and diffuse ground glass opacities in the upper lobes. Blood tests showed elevated white blood cell, C-reactive protein, surfactant protein D, and Krebs von den Lungen-6 levels. After an antigen avoidance test, his HRCT and blood test findings improved; we diagnosed him with hypersensitivity pneumonitis (HP). A culture of the rotting interior walls within his home revealed Paecilomyces, which we believe caused his HP. Given the few patients with Paecilomyces-induced HP, systematic approach was important to identify the inciting antigen.

Spontaneous regression of acute fibrinous organizing pneumonia induced by COVID-19 vaccination: A case report.

A 42-year-old woman visited our hospital with complaints of fever, muscle pain, and dyspnea one week after receiving the coronavirus disease 2019 (COVID-19) vaccine. Chest high-resolution computed tomography showed a patchy consolidation and ground-glass attenuation in the both lungs, consistent with acute interstitial pneumonia. Transbronchial lung cryobiopsy revealed organizing pneumonia with marked intra-alveolar fibrin, and pathologically diagnosed as acute fibrinous organizing pneumonia (AFOP). Other causative diseases such as dermatomyositis was clinically ruled out, and COVID-19 vaccine-induced AFOP was diagnosed. Physician should check the history of COVID-19 vaccination when encountering a case of AFOP with an unknown cause.

Bilateral Pneumothorax after a Transbronchial Lung Cryobiopsy for Interstitial Lung Disease.

We herein report a case of bilateral pneumothorax after a unilateral transbronchial lung cryobiopsy (TBLC). A 73-year-old man with no history of cardiothoracic surgery underwent a TBLC for the reevaluation of interstitial lung disease. Five hours later, he developed bilateral pneumothorax, pneumomediastinum, and subcutaneous emphysema. He underwent bilateral chest drainage and was discharged 18 days later. The lung biopsy specimens obtained from the TBLC contained visceral pleura and bronchial cartilage, suggesting bronchial injury as the cause of the bilateral pneumothorax.

Japanese clinical practice guide 2022 for hypersensitivity pneumonitis.

Considering recently published two guidelines for the diagnosis of hypersensitivity pneumonitis (HP), the Japanese Respiratory Society (JRS) has now published its own Japanese clinical practice guide for HP. Major types of HP in Japan include summer-type, home-related, bird-related, farmer's lung, painter's lung, humidifier lung, and mushroom grower's lung. Identifying causative antigens is critical for increasing diagnostic confidence, as well as improving prognosis through appropriate antigen avoidance. This guide proposes a comprehensive antigen questionnaire including the outbreak sources reported in Japan. Drawing on the 2021 CHEST guideline, this guide highlights the antigen identification confidence level and adaptations for environmental surveys. The detection of specific antibodies against causative antigens is an important diagnostic predictor of HP. In Japan, the assessments of bird-specific IgG (pigeons, budgerigars) and the Trichosporon asahii antibody are covered by medical insurance. Although this guide adopts the 2020 ATS/JRS/ALAT guideline diagnostic criteria based on the combination of imaging findings, exposure assessment, bronchoalveolar lavage lymphocytosis, and histopathological findings, it added some annotations to facilitate the interpretation of the content and correlate the medical situation in Japan. It recommends checking biomarkers; seasonal changes in the KL-6 concentration (increase in winter for bird-related HP/humidifier lung and in summer for summer-type HP) and high KL-6 concentrations providing a basis for the suspicion of HP. Antigen avoidance is critical for disease management of HP. This guide also addresses the pharmacological management of HP, highlighting the treatment strategy for fibrotic HP including combination therapies with anti-inflammatory/immunosuppressive and antifibrotic drugs.

Concordance between transbronchial lung cryobiopsy and surgical lung biopsy in patients with idiopathic multicentric Castleman disease: A report of four cases.

BACKGROUND: Idiopathic multicentric Castleman disease (iMCD) is a rare polyclonal lymphoproliferative disease often associated with pulmonary involvement. Recently, transbronchial lung cryobiopsy (TBLC) has been reported to be useful for the diagnosis of diffuse interstitial lung disease. However, there have been no reports of pathological assessment of TBLC for iMCD. METHOD: To clarify the efficacy of TBLC in the diagnosis of iMCD, we retrospectively reviewed four iMCD patients who had undergone both TBLC and surgical lung biopsy (SLB). RESULTS: The median age was 44 years; 2 males and 2 females. Two or three TBLC specimens were taken from each patient. All patients had no complications other than minimal bleeding. The size of the TBLC specimens was approximately 5-6 × 3-4 mm, and the alveolar region, and centrilobular and perilobular areas were adequately sampled. As with SLB, the extent of lung lesions and inflammatory cell infiltration could be sufficiently evaluated by TBLC. The presence of lymphoid follicles could also be assessed by TBLC; however, the germinal centers with lymphoid follicles were difficult to evaluate. The TBLC specimens could also be evaluated for immunostaining, especially IgG4 immunostaining, to rule out IgG4-related lung disease. Pulmonary pathological grading showed a high concordance rate between major pathological findings of TBLC and SLB. The pathologist's confidence level of TBLC for the diagnosis of iMCD was high in all cases. CONCLUSIONS: TBLC exhibits a high concordance rate with SLB in the pathological evaluation of iMCD, which may be useful for the diagnosis of iMCD.

Histologically Proven Recurrent Synovitis after Nivolumab Treatment.

A 58-year-old woman with rheumatoid arthritis was diagnosed with methotrexate-associated Hodgkin lymphoma. After receiving several chemotherapy regimens, she started nivolumab treatment. Two weeks later, she was hospitalized with worsening finger, wrist, and elbow joint pain. A synovial biopsy of the wrist joint showed villous synovial proliferation and linear infiltration of CD68-/CD3-positive T cells (with more CD8 than CD4 T cells) but no CD20-positive B cells or CD138-positive macrophages. These findings corresponded to synovitis associated with immune-related adverse events, which are induced mainly by T cells and are different from typical rheumatoid arthritis (RA), in which B cells play a central role.

High prevalence of upper lung field pulmonary fibrosis radiologically consistent with pleuroparenchymal fibroelastosis in patients with round atelectasis.

BACKGROUND: Upper-lung field pulmonary fibrosis (upper-PF), radiologically consistent with pleuroparenchymal fibroelastosis (PPFE), was reported to develop in patients with a history of asbestos exposure and tuberculous pleurisy, indicating that chronic pleuritis is correlated with upper-PF development. Round atelectasis reportedly emerges after chronic pleuritis. This study aimed to clarify the association between round atelectasis and upper-PF. METHODS: We examined the radiological reports of all consecutive patients with round atelectasis between 2006 and 2018 and investigated the incidence of upper-PF development. RESULTS: Among 85 patients with round atelectasis, 21 patients (24.7%) were confirmed to finally develop upper-PF lesions. Upper-PF was diagnosed after round atelectasis recognition in more than half of the patients (13/21, 61.9%), whereas upper-PF and round atelectasis were simultaneously detected in the remaining 8 patients. At the time of round atelectasis detection, almost all patients (19/21, 90.5%) had diffuse pleural thickening and round atelectasis was commonly observed in non-upper lobes of 19 patients (90.5%). Fourteen patients had round atelectasis in unilateral lung, and the remaining 7 patients had round atelectasis in bilateral lungs. Among all 14 patients with unilateral round atelectasis, upper-PF developed on the same (n = 11) or both sides (n = 3). Thus, upper-PF emerged on the same side where round atelectasis was present (14/14, 100%). The autopsy of one patient revealed a thickened parietal-visceral pleura suggestive of chronic pleuritis. Subpleural fibroelastosis was also observed. CONCLUSIONS: Upper-PF occasionally develops on the same side of round atelectasis. Upper-PF may develop as a sequela of chronic pleuritis.

Very-late-onset interstitial pneumonia suspected to be related to liver transplantation more than 10 years ago.

Pulmonary complications after liver transplantation are common in the postoperative period, becoming less frequent in the subsequent months, and rare after 1 year. However, we encountered two cases of very-late-onset interstitial pneumonia suspected to be related to liver transplantation after 14 and 15 years. Both patients presented with non-specific interstitial pneumonia patterns, which significantly improved with corticosteroid therapy. Physicians should be aware of such complications and monitor them after liver transplantation.

Acute Exacerbation and Proposed Criteria for Progressive Pulmonary Fibrosis in Patients with Fibrotic Hypersensitivity Pneumonitis and Idiopathic Pulmonary Fibrosis.

BACKGROUND: Acute exacerbation (AE) occasionally develops in the course of fibrotic hypersensitivity pneumonitis (HP). OBJECTIVE: The aim of the study was to compare AE of fibrotic HP with that of idiopathic pulmonary fibrosis (IPF). METHODS: Consecutive patients with pathologically confirmed fibrotic HP and IPF diagnosed based on a multidisciplinary discussion were included in the analysis. AE in patients with fibrotic HP and IPF was evaluated retrospectively. RESULTS: This study included 309 and 160 patients with fibrotic HP and IPF, respectively. Their 50% survival times were 96.1 and 78.0 months, respectively (hazard ratio [HR]: 0.54 [95% confidence interval, CI: 0.36-0.77], log-rank test; p < 0.001). Notably, the cumulative AE rates of fibrotic HP were 3% at 1 year and 10% at 3 years. Moreover, the corresponding rates of IPF were 8% at 1 year and 20% at 3 years (HR: 0.66 [95% CI: 0.45-0.93], log-rank test; p = 0.034). The 90-day survival rates from the AE onset of fibrotic HP and IPF were 75% and 64%, respectively (HR: 0.51 [95% CI: 0.31-0.83], log-rank test; p = 0.006). The respiratory function test on the physiological criteria of progressive pulmonary fibrosis (PPF) was a predictor of AE in fibrotic HP. However, the high-resolution CT (HRCT) changes in the criteria of PPF were not. Nevertheless, both the physiological and radiological criteria of PPF were a predictor of AE of IPF. CONCLUSION: AE of fibrotic HP has a lesser prognostic effect than that of IPF. HRCT criteria for PPF were not a risk factor for AE in patients with fibrotic HP.

Concordance between transbronchial lung cryobiopsy and surgical lung biopsy for interstitial lung disease in the same patients.

BACKGROUND: The diagnostic accuracy and safety of transbronchial lung cryobiopsy (TBLC) via a flexible bronchoscope under sedation compared with that of surgical lung biopsy (SLB) in the same patients is unknown. METHODS: Retrospectively the data of fifty-two patients with interstitial lung diseases (median age: 63.5 years; 21 auto-antibody positive) who underwent TBLC followed by SLB (median time from TBLC to SLB: 57 days) was collected. The samples from TBLC and SLB were randomly labelled to mask the relationship between the two samples. Diagnosis was made independently by pathologists, radiologists, and pulmonary physicians in a stepwise manner, and a final diagnosis was made at multidisciplinary discussion (MDD). In each diagnostic step the specific diagnosis, the diagnostic confidence level, idiopathic pulmonary fibrosis (IPF) diagnostic guideline criteria, and treatment strategy were recorded. RESULTS: Without clinical and radiological information, the agreement between the histological diagnoses by TBLC and SLB was 42.3% (kappa [κ] = 0.23, 95% confidence interval [CI]: 0.08-0.39). However, the agreement between the TBLC-MDD and SLB-MDD diagnoses and IPF/non-IPF diagnosis using the two biopsy methods was 65.4% (κ = 0.57, 95% CI: 0.42-0.73) and 90.4% (47/52), respectively. Out of 38 (73.1%) cases diagnosed with high or definite confidence at TBLC-MDD, 29 had concordant SLB-MDD diagnoses (agreement: 76.3%, κ = 0.71, 95% CI: 0.55-0.87), and the agreement for IPF/non-IPF diagnoses was 97.4% (37/38). By adding the pathological diagnosis, the inter-observer agreement of clinical diagnosis improved from κ = 0.22 to κ = 0.42 for TBLC and from κ = 0.27 to κ = 0.38 for SLB, and the prevalence of high or definite diagnostic confidence improved from 23.0% to 73.0% and from 17.3% to 73.0%, respectively. Of all 383 TBLC performed during the same period, pneumothorax occurred in 5.0% of cases, and no severe bleeding, acute exacerbation of interstitial lung disease, or fatal event was observed. CONCLUSIONS: TBLC via a flexible bronchoscope under deep sedation is safely performed, and the TBLC-MDD diagnosis with a high or definite confidence level is concordant with the SLB-MDD diagnosis in the same patients.

Multidisciplinary Discussion for Fibrotic Hypersensitivity Pneumonitis with a Positive Antigen Avoidance.

Background: In the two fibrotic hypersensitivity pneumonitis (fHP) diagnostic guidelines, the multidisciplinary discussion (MDD) is required to be performed in diagnosis of fHP, as in idiopathic pulmonary fibrosis (IPF) diagnostic guideline. Although some patients with fHP can improve disease condition during antigen avoidance, which can facilitate the diagnosis of fHP, it is unclear if MDD is necessary in all patients with suspected fHP who improved an antigen avoidance. Objective: To investigate the diagnosis of fHP via MDD with positive antigen avoidance tests (AATs) and the clinical diagnosis with positive AATs. Methods: A single-center, retrospective study was conducted. Between 2012 and 2019, patients with fHP were enrolled in the study. Patients in the MDD diagnostic group consisted of patients diagnosed with MDD, including histopathology findings and positive ATTs, and patients in the clinical diagnostic group were diagnosed by two respiratory physicians and had positive ATTs. Results: AAT was performed on 72 of 219 patients, and 58 had positive AATs. The study included 37 patients in the MDD diagnosis group and 21 patients in the clinical diagnosis group. No significant differences in overall survival (OS) were detected between the two groups (HR: 1.99 [95% CI: 0.82‒4.83], p = 0.127). The conducting MDD was not a risk factor for OS; only <79% forced vital capacity was a risk factor in the multivariate Cox hazard regression analysis. No significant difference in annual changes of forced vital capacity, diffusion of the lung for carbon monoxide and Krebs von den Lungen-6 between the MDD diagnostic and the clinical diagnostic groups were observed (p = 0.41, 0.79, and 0.81, respectively). Conclusion: In patients with positive AATs, the disease progression of the MDD diagnostic and the clinical diagnostic groups were similar. Therefore, MDD could not be necessary in all patients with suspected fHP who had positive AATs.