Risk of hypersensitivity pneumonitis and other interstitial lung diseases following organic dust exposure.

BACKGROUND: Organic dust is associated with hypersensitivity pneumonitis, and associations with other types of interstitial lung disease (ILD) have been suggested. We examined the association between occupational organic dust exposure and hypersensitivity pneumonitis and other ILDs in a cohort study. METHODS: The study population included all residents of Denmark born in 1956 or later with at least 1 year of gainful employment since 1976. Incident cases of hypersensitivity pneumonitis and other ILDs were identified in the Danish National Patient Register 1994-2015. Job exposure matrices were used to assign individual annual levels of exposure to organic dust, endotoxin and wood dust from 1976 to 2015. We analysed exposure-response relations by different exposure metrics using a discrete-time hazard model. RESULTS: For organic dust, we observed increasing risk with increasing cumulative exposure with incidence rate ratios (IRR) per 10 unit-years of 1.19 (95% CI 1.12 to 1.27) for hypersensitivity pneumonitis and 1.04 (95% CI 1.02 to 1.06) for other ILDs. We found increasing risk with increasing cumulative endotoxin exposure for hypersensitivity pneumonitis and other ILDs with IRRs per 5000 endotoxin units/m3-years of 1.55 (95% CI 1.38 to 1.73) and 1.09 (95% CI 1.00 to 1.19), respectively. For both exposures, risk also increased with increasing duration of exposure and recent exposure. No increased risks were observed for wood dust exposure. CONCLUSION: Exposure-response relations were observed between organic dust and endotoxin exposure and hypersensitivity pneumonitis and other ILDs, with lower risk estimates for the latter. The findings indicate that organic dust should be considered a possible cause of any ILD. TRIAL REGISTRATION NUMBER: j.no.: 1-16-02-196-17.

A new definition and treatment options of allergic alveolitis.

In this review, we discuss a new definition and treatment options of allergic alveolitis (AA). AA is an immune-mediated interstitial lung disease triggered by inhaled antigens, it is defined as non-fibrotic (inflammatory) and/or fibrotic, and diagnosis relies on a multidisciplinary approach using clinical, radiological and sometimes histological assessments. Treatment involves early antigen elimination and may include corticosteroids or other immunosuppressants. Prognosis varies from reversible inflammation to irreversible fibrosis. Early detection is crucial for better outcomes.

The asbestos-asbestosis exposure-response relationship: a cohort study of the general working population.

OBJECTIVES: The association between asbestos exposure and asbestosis in high-exposed industrial cohorts is well-known, but there is a lack of knowledge about the exposure-response relationship for asbestosis in a general working population setting. We examined the exposure-response relationship between occupational asbestos exposure and asbestosis in asbestos-exposed workers of the Danish general working population. METHODS: We followed all asbestos-exposed workers from 1979 to 2015 and identified incident cases of asbestosis using the Danish National Patient Register. Individual asbestos exposure was estimated with a quantitative job exposure matrix (SYN-JEM) from 1976 onwards and back-extrapolated to age 16 for those exposed in 1976. Exposure-response relations for cumulative exposure and other exposure metrics were analyzed using a discrete time hazard model and adjusted for potential confounders. RESULTS: The range of cumulative exposure in the population was 0.001 to 18 fibers per milliliter-year (f/ml-year). We found increasing incidence rate ratios (IRR) of asbestosis with increasing cumulative asbestos exposure with a fully adjusted IRR per 1 f/ml-years of 1.18 [95% confidence interval (CI) 1.15- -1.22]. The IRR was 1.94 (95% CI 1.53-2.47) in the highest compared to the lowest exposure tertile. We similarly observed increasing risk with increasing cumulative exposure in the inception population. CONCLUSIONS: This study found exposure-response relations between cumulative asbestos exposure and incident asbestosis in the Danish general working population with mainly low-level exposed occupations, but there is some uncertainty regarding the exposure levels.

Systemic Lupus Erythematosus-related Lung Disease.

Systemic Lupus Erythematosus (SLE) is a multifaceted, multisystem autoimmune disorder with diverse clinical expressions. While prevalence reports vary widely, pulmonary involvement accounts for significant morbidity and mortality in SLE. This comprehensive review explores the spectrum of pulmonary disease in SLE, including upper airway manifestations (e.g., laryngeal affection), lower airway conditions (e.g., bronchitis, bronchiolitis, bronchiectasis), parenchymal diseases (e.g., interstitial lung disease, acute lupus pneumonitis, diffuse alveolar hemorrhage), pleural diseases (e.g., serositis, shrinking lung syndrome), and vascular diseases (e.g., pulmonary arterial hypertension, pulmonary embolism, acute reversible hypoxemia syndrome). We discuss diagnostic modalities, treatment strategies, and prognosis for each pulmonary manifestation. With diagnostics remaining a challenge and with the absence of standardized treatment guidelines, we emphasize the need for evidence-based guidelines to optimize patient care and improve outcomes in this complex disease.

Case report: If it is not asthma-think of lymphangioleiomyomatosis in younger female patients.

Lymphangioleiomyomatosis (LAM) is a rare lung disease predominantly affecting women, and it is characterized by the proliferation of smooth muscle cells and cystic lung destruction. LAM diagnosis is challenging due to varied clinical presentations and resemblance to common conditions such as asthma. We present two female cases where LAM was initially misdiagnosed. Case 1 describes a woman treated for asthma-chronic obstruction pulmonary disease overlap syndrome, while also undergoing treatment with vascular endothelial growth factor (VEGF) inhibitor pazopanib for a retroperitoneal leiomyoma, the latter responding well to treatment. Due to progressive dyspnea, pazopanib-induced pneumonitis was suspected. High-resolution computed tomography (HRCT) showed changes compatible with LAM. A revision of biopsies showed that the leiomyoma was in fact a lymphangioleiomyoma, and VEGF-D was increased. Both supported the LAM diagnosis. Treatment with mTORC1 inhibitor sirolimus was initiated. Case 2 describes a woman, who in resemblance with the woman from case 2 was also suspected of asthma and did not respond clinically to treatment. After several years, HRCT was performed and suspicion of LAM was raised. Transbronchial biopsy and later, an increased VEGF-D supported the LAM diagnosis. As in case 1, treatment with sirolimus was initiated. These cases underscore the importance of reevaluating diagnoses when treatments fail to yield expected results. Improved awareness and early detection of LAM can enhance patient outcomes and life quality. Early LAM diagnosis is vital as mTORC1 inhibitors such as sirolimus can prevent further decline in lung function. Notably, the response of case 2 to pazopanib treatment supports suggestions of its potential as a second-line therapy for perivascular epithelioid cell tumors (PEComas), including LAM.

Validity and reliability of measurement of peripheral oxygen saturation during the 6-Minute Walk Test in patients with systemic sclerosis.

Peripheral oxygen saturation (SpO2) using the fingers may have important limitations due to Raynaud's phenomenon and sclerodactyly in patients with systemic sclerosis (SSc). Sensors located at more central body positions may be more accurate as these as less prone to Raynaud attacks. To determine the validity and reliability of the SpO2 measured at the finger, forehead, and earlobe during the 6-Minute Walk Test (6MWT). Eighty two patients with SSc had an arterial line placed while performing the 6MWT. Peripheral oxygen saturation was simultaneously measured by finger, forehead, and earlobe sensors and compared to the arterial oxygen saturation (SaO2) measured before and after the 6MWT. 40 patients repeated the 6MWT one week later to determine re-test reliability. We used Bland-Altman plots to display the agreement between SpO2 and SaO2. The intraclass correlation coefficient for repeated measurement of minimum SpO2 was calculated. The mean difference between SpO2 and SaO2 after the 6MWT was - 3% (SD: ± 5), 0% (SD: ± 2), and 1% (SD: ± 2) for the finger, forehead, and earlobe, respectively. The minimum SpO2 measured at the finger demonstrated the poorest re-test reliability: The ICC (95% CI) showed good agreement using the ear and forehead probe (ICCear = 0.89 [95% CI 0.80; 0.94]; ICCforehead = 0.77 [95% CI 0.60; 0.87]), while a modest reliability was found using the finger probe (ICCfinger = 0.65 95% CI [0.43; 0.80]). SpO2 should be measured using either the earlobe or forehead during the 6MWT in patients with SSc. Clinical Trials.Gov (NCT04650659).

Thrombelastography and Conventional Coagulation Markers in Chronic Obstructive Pulmonary Disease: A Prospective Paired-Measurements Study Comparing Exacerbation and Stable Phases.

Chronic Obstructive Pulmonary Disease (COPD) exacerbation is known for its substantial impact on morbidity and mortality among affected patients, creating a significant healthcare burden worldwide. Coagulation abnormalities have emerged as potential contributors to exacerbation pathogenesis, raising concerns about increased thrombotic events during exacerbation. The aim of this study was to explore the differences in thrombelastography (TEG) parameters and coagulation markers in COPD patients during admission with exacerbation and at a follow-up after discharge. This was a multi-center cohort study. COPD patients were enrolled within 72 h of hospitalization. The baseline assessments were Kaolin-TEG and blood samples. Statistical analysis involved using descriptive statistics; the main analysis was a paired t-test comparing coagulation parameters between exacerbation and follow-up. One hundred patients participated, 66% of whom were female, with a median age of 78.5 years and comorbidities including atrial fibrillation (18%) and essential arterial hypertension (45%), and sixty-five individuals completed a follow-up after discharge. No significant variations were observed in Kaolin-TEG or conventional coagulation markers between exacerbation and follow-up. The Activated Partial Thromboplastin Clotting Time (APTT) results were near-significant, with p = 0.08. In conclusion, TEG parameters displayed no significant alterations between exacerbation and follow-up.

Perceptions on Use of Opioids in Palliative Care of Dyspnoea in Patients with Fibrotic interstitial lung disease and Chronic Obstructive Pulmonary Disease: A Qualitative Study.

BACKGROUND: Many patients with chronic obstructive pulmonary disease and fibrotic interstitial lung disease suffer from severe dyspnea and reduced quality of life, despite receiving optimal disease-modifying treatment for their illness. Studies have suggested that these patients may benefit from treatment with low-dose opioids. However, many patients decline opioid treatment. This has led to patients not receiving proper palliative treatment of their lung disease. AIM: To identify potential barriers that prevent patients from receiving adequate palliative care with opioids and enable doctors to address patients' concerns. DESIGN: A qualitative study based on semi-structured interviews. Interviews were transcribed and thematic analysis was done using NVivo. SETTING/PARTICIPANTS: Patients were recruited when scheduled for out-patient follow-up at Center for Rare Lung Diseases or at the COPD clinic, Aarhus University Hospital. Eligible patients were 18 years of age, did not currently receive opioids or had ever received opioids for dyspnea. RESULTS: A total of 28 patients participated. One patient was excluded before final analysis of 27 patients. Four themes were identified: Fear of side-effects, Need for more information, Stigma of opioids association with severe illness and dying, and No discernible barriers. Furthermore, three sub-themes to Fear of side-effects were identified: Fear of addiction, concern for sedative effect, and fear for loss of mobility due to inability to drive a car. The most expressed concern was Fear of side-effects, especially addiction. CONCLUSIONS: Pre-conceived notions about opioids prevent some patients with chronic obstructive lung disease or interstitial lung disease from receiving palliative care for breathlessness.

Identification and management of interstitial lung abnormalities.

Interstitial lung abnormalities (ILA) are incidentally observed specific CT findings in patients without clinical suspicion of interstitial lung disease (ILD). ILA with basal and peripheral predominance and features suggestive of fibrosis in more than 5% of any part of the lung should be referred for pulmonologist review. The strategy for monitoring as described in this review is based on clinical and radiological risk factors. ILA are associated with risk of progression to ILD and increased mortality. Early identification and assessment of risk factors for progression are essential to improve outcome.

The usual Interstitial pneumonia pattern in autoimmune rheumatic diseases.

Usual Interstitial Pneumonia (UIP) is characterized by progression of lung parenchyma that may be observed in various autoimmune rheumatic diseases (ARDs), including rheumatoid arthritis and connective tissue diseases. From a diagnostic point of view, a UIP pattern related to ARDs may display imaging and pathological features able to distinguish it from that related to IPF, such as the "straight-edge" sign at HRCT and lymphoplasmacytic infiltrates at histologic specimens. Multidisciplinary approach (MDD), involving at least pulmonologist, rheumatologist and radiologist, is fundamental in the differential diagnosis process, but MDD is also required in the evaluation of severity, progression and response to treatment, that is based on the combination of changes in symptoms, pulmonary function trends, and, in selected patients, serial CT evaluation. Differently from IPF, in patients with ARDs both functional evaluation and patient-reported outcomes may be affected by systemic involvement and comorbidities, including musculoskeletal manifestations of disease. Finally, in regards to pharmacological treatment, immunosuppressants have been considered the cornerstone of therapy, despite the lack of solid evidence in most cases; recently, antifibrotic drugs were also proposed for the treatment of progressive fibrosing ILDs other than IPF. In ARD-ILD, the therapeutic choice should balance the need for the control of systemic and lung involvements with the risk of adverse events from multi-morbidities and -therapies. Purpose of this review is to summarize the definition, the radiological and morphological features of the UIP pattern in ARDs, together with risk factors, diagnostic criteria, prognostic evaluation, monitoring and management approaches of the UIP-ARDs.

A rare case of sarcoid myelitis complicating Löfgren's syndrome.

Neurosarcoidosis is a rare and serious condition. Rapid diagnosis and treatment are crucial to prevent morbidity and mortality. When neurological symptoms are not present at the time of diagnosis, CNS involvement can be undetected. We present a case of neurosarcoidosis complicating Löfgren's syndrome and discus the challenges in diagnostics and treatment, that can be encountered.

Endobronchial valve treatment in chronic obstructive pulmonary disease: A qualitative study of patients' expectations.

Objectives: Endobronchial valve (EBV) treatment is a treatment option for selected patients with severe chronic obstructive pulmonary disease (COPD) to reduce dyspnea and improve quality of life. However, the procedure is associated with risk of complications, and not all patients achieve the expected outcomes. The present study explores patients' expectations while waiting for EBV treatment. Methods: Fifteen patients accepted for EBV treatment at Aarhus University Hospital in Denmark from October 2020 to June 2021 participated in a 30-min, semi-structured interview about (1) the experience of living with COPD and (2) expectations regarding EBV. Results: Four themes were identified: a life of reduced quality; hopes and expectations; information about EBV; and perception of risks. Most patients described their lives as not worth living, and they hoped that EBV would give them their physical and social lives back, while also being aware that EBV would probably not work miracles. Patients' information seeking was influenced by their hopes and expectations to the treatment. They filtered out negative information, focusing on the hope for a positive outcome. This made them willing to run the risk of complications. Conclusion: Living a life of considerably reduced quality, patients might have an increased focus on potential positive effects of EBV treatment while filtering out information about potential side effects. This might bias their decision-making process.

Comorbidity and mortality in systemic sclerosis and matched controls: Impact of interstitial lung disease. A population based cohort study based on health registry data.

OBJECTIVE: This population-based, matched cohort study evaluates the impact of comorbidities on mortality among systemic sclerosis (SSc) patients with and without interstitial lung disease (ILD). METHOD: Patients with a first-time SSc diagnosis between 2002 and 2015 were identified in the Danish National Patient Registry, separated into two cohorts - with ILD (SSc-ILD) and without ILD (non-ILD SSc), and matched 1:4 with controls from the general population on age, sex, residency and marital status. Comorbidity and mortality data were obtained from national registries. The Deyo-Charlson comorbidity score (DCcs) was used for assessment of the burden of comorbidities. RESULTS: 1732 patients with SSc and 6919 controls were included; 258 (14.9%) patients had SSc-ILD. The hazard ratio (HR) for death was 2.8 (95% CI 2.4-3.3) in SSc, and especially increased in SSc-ILD (HR 4.2 (95% CI 3.2-5.4)), males (HR 3.1 95% CI 2.4-4.1) and younger adults (aged 18-40 (HR 6.9, 95% CI 3.4-14.2) and 41-50 (HR 7.7, 95% CI 3.8-15.6)). In non-ILD SSc, mortality increased with increasing DCcs. Cancer was the most frequent cause of death in SSc (24.9% of deaths) and in controls (33.5%), in SSc followed by musculoskeletal and connective tissue diseases (22.7%); the cause of only 0.8% of deaths among controls. CONCLUSION: The high prevalence of comorbidities in SSc had extensive impact on mortality. Mortality was increased in males, in young adults and in SSc-ILD, underlining the excess mortality associated with ILD. These findings emphasise the importance of timely diagnosis and optimal management of organ involvement and comorbidities in SSc.

Decline in forced vital capacity as a surrogate for mortality in patients with pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Surrogate endpoints enable determination of meaningful treatment effects more efficiently than applying the endpoint of ultimate interest. We used data from trials of nintedanib in subjects with pulmonary fibrosis to assess decline in forced vital capacity (FVC) as a surrogate for mortality. METHODS: Data from the nintedanib and placebo groups of trials in subjects with idiopathic pulmonary fibrosis, other forms of progressive pulmonary fibrosis, and pulmonary fibrosis due to systemic sclerosis (NCT00514683, NCT01335464, NCT01335477, NCT01979952, NCT02999178, NCT02597933) were pooled. Using joint models for longitudinal and time-to-event data, we assessed the association between decline in FVC % predicted and time to death over 52 weeks. The rate of change in FVC % predicted and the current value of FVC % predicted were modelled longitudinally and estimates applied as predictors in time-to-event models. RESULTS: Among 2583 subjects with pulmonary fibrosis, both a greater rate of decline in FVC % predicted and a lower current value of FVC % predicted were associated with an increased risk of death over 52 weeks (HR 1.79 [95% CI: 1.57, 2.03] and HR 1.24 [1.17, 1.32] per 5-percentage point decrease, respectively). Associations between the rate of change in FVC % predicted and the risk of death were consistent between patients with IPF and other ILDs. CONCLUSION: Data from clinical trials in subjects with pulmonary fibrosis of diverse aetiology demonstrate a strong association between decline in FVC % predicted and mortality over 52 weeks, supporting FVC decline as a surrogate for mortality in these patients.

Association between Parenchymal B-Cell Follicles and CT-Proven Enlarged Mediastinal Lymph Nodes in Patients with Pulmonary Fibrosis.

BACKGROUND: Mediastinal lymph node enlargement (MLNE) is a finding described in a subset of patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs) and is associated with accelerated disease progression and increased mortality. The cause of MLNE is still not known. Our hypothesis is that there is an association between MLNE and B-cell follicles in lung tissue, another aspect detectable in the lung tissue of patients with IPF and other ILDs. OBJECTIVES: The aim of this study was to assess if there is an association between MLNE and B-cell follicles in lung tissue in patients with IPF and other ILDs. METHOD: Patients having transbronchial cryobiopsies performed as part of an investigation for ILD were included in this prospective observational study. MLNE (smallest diameter ≥10 mm) were assessed in station 7, 4R, and 4L on high-resolution computed tomography scans. B-cell follicles were assessed on haematoxylin-eosin-stained specimens. Lung function, 6-minute walk test, acute exacerbation, and mortality were registered after 2 years. In addition, we investigated if the finding of B-cell follicles was consistent in patients who underwent both surgical lung biopsies (SLBs) and cryobiopsies. RESULTS: In total, 93 patients were included for analysis (46% diagnosed with IPF, 54% diagnosed with other ILDs). MLNE was found in 26 (60%) of the IPF patients and in 23 (46%) of the non-IPF patients (p = 0.164). Diffusing capacity for carbon monoxide was significantly lower (p = 0.03) in patients with MLNE compared to patients without MLNE. B-cell follicles were found in 11 (26%) of the IPF patients and in 22 (44%) of the non-IPF patients (p = 0.064). Germinal centres were not seen in any of the patients. There was no association between MLNE and B-cell follicles (p = 0.057). No significant difference in change of pulmonary function test was seen at 2-year follow-up when comparing the patients with and without MLNE or B-cell follicles. In 13 patients, both SLBs and cryobiopsies were performed. The presence of B-cell follicles was not consistent when comparing the two different methods. CONCLUSION: MLNE is evident in a substantial part of patients with ILD and is associated with lower DLCO at inclusion. We could not demonstrate an association between histological B-cell follicles in biopsies and MLNE. A possible explanation for this is that the cryobiopsies might not have captured the changes we sought.

Lung abscess: Clinical characteristics of 222 Danish patients diagnosed from 2016 to 2021.

INTRODUCTION: Lung abscess (LA) is a serious respiratory infection often followed by several weeks of antibiotic treatment. This study described the clinical presentation of LA, treatment duration and mortality in a contemporary Danish population. METHODS: In a retrospective multicenter cohort study at four Danish hospitals, patients diagnosed with LA were identified using the International Classification of Diseases and Related Health Problems 10th revision (ICD-10) between 2016 and 2021. A predefined data collection tool was used to extract data on demographics, symptoms, clinical findings and treatment. RESULTS: Of 302 patients, 222 with LA were included after review of patient records (76%). Mean age was 65 years (54-74), 62.9% was male and 74.9% were ever-smokers. Chronic obstructive pulmonary disease (COPD) (35.1%), use of sedatives (29.3%) and alcohol abuse (21.8%) were common risk factors. Dental status was reported in 51.4%, whereof 41.6% had poor dental status. Patients presented with cough (78.8%), malaise (61.3%) and fever (56.8%) Patients were hospitalized for a median of 14 days (interquartile ranges, IQR 7-21) and median duration of antibiotic treatment was 38 days (IQR 30-51). All-cause mortality after 1, 3 and 12 months was 2.7%, 7.7% and 15.8%, respectively. CONCLUSION: Risk factors for LA include COPD and use of sedatives, alcohol abuse, and poor dental status. Despite long-term antibiotic treatment, long-term mortality is markedly high.

Fibrin degradation products and survival in patients with chronic obstructive pulmonary disease: a protocolized prospective observational study.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) have a high incidence of cardiovascular disease including thromboembolisms. Fibrin degradation products, like D-dimer, have been associated with death from all causes in healthy individuals and COPD patients. We aimed to determine the (i) association between D-dimer levels and all-cause mortality and time being alive and out of a hospital, (ii) possible modifying effect of anticoagulant treatment,, and (iii) distribution of D-dimer in patients with moderate to severe COPD. METHODS: Results of routinely measured stable phase D-dimer samples from COPD-outpatients at Copenhagen University Hospital - Herlev and Gentofte, COPD-outpatient clinic were collected using the Danish registries. These were used to examine whether COPD-patients with a D-dimer level in the upper quartile, had a higher risk of death from all causes within 365 days. RESULTS: In the unadjusted Cox proportional hazards regression we found an association between high D-dimer and all-cause mortality: Hazard ratio (HR): 2.3 (95% Confidence Interval (CI) 1.1-4.7). In the fully adjusted regression, the HR was 1.8 (CI 0.8-3.9). We did not find any interaction between D-dimer and anticoagulant or antiplatelet therapy. For the secondary outcome, proportion of days alive and out of hospital in 365 days (pDAOH), the unadjusted multiple linear regression had an association between high D-dimer level and pDAOH: -2.7% points (pp) (CI -3.9 pp - -1.5 pp), which was attenuated to -1,7pp (-2.9pp - -0.4pp) in the fully adjusted regression. CONCLUSIONS: In patients with moderate to severe COPD, patients with a high level of D-dimer were more likely to die; however, the signal was not strong in the adjusted analyses and our results do not support unselected risk stratification with D-dimer in COPD-outpatients.

A serologically assessed neo-epitope biomarker of cellular fibronectin degradation is related to pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterized by excessive extracellular matrix (ECM) remodeling, herein ECM degradation. Fibronectin (FN) is an important component of the ECM that is produced by multiple cell types, including fibroblasts. Extra domain B (EDB) is specific for a cellular FN isoform which is found in the ECM. We sought to develop a non-invasive test to investigate whether matrix metalloproteinase 8 (MMP-8) degradation of EDB in cellular FN results in a specific protein fragment that can be assessed serologically and if levels relate to pulmonary fibrosis. METHOD: Cellular FN was cleaved in vitro by MMP-8 and a protein fragment was identified by mass spectrometry. A monoclonal antibody (mAb) was generated, targeting a neo-epitope originating from EDB in cellular FN. Utilizing this mAb, a neo-epitope specific enzyme-linked immunosorbent assay (FN-EDB) was developed and technically validated. Serum FN-EDB was assessed in an IPF cohort (n = 98), registered at clinicaltrials.gov (NCT02818712), and in healthy controls (n = 35). RESULTS: The FN-EDB assay had high specificity for the MMP-8 degraded neo-epitope and was technically robust. FN-EDB serum levels were not influenced by age, sex, ethnicity, or BMI. Moreover, FN-EDB serum levels were significantly higher in IPF patients (median 31.38 [IQR 25.79-46.84] ng/mL) as compared to healthy controls (median 28.05 [IQR 21.58-33.88] ng/mL, p = 0.023). CONCLUSION: We developed the neo-epitope specific FN-EDB assay, a competitive ELISA, as a tool for serological assessment of MMP-8 mediated degradation of EDB in cellular FN. This study indicates that degradation of EDB in cellular FN is elevated in IPF and warrants further investigation.

New insights in the genetic variant spectrum of SLC34A2 in pulmonary alveolar microlithiasis; a systematic review.

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive lung disease caused by variants in the SLC34A2 gene encoding the sodium-dependent phosphate transport protein 2B, NaPi-2b. PAM is characterized by deposition of calcium phosphate crystals in the alveoli. Onset and clinical course vary considerably; some patients remain asymptomatic while others develop severe respiratory failure with a significant symptom burden and compromised survival. It is likely that PAM is under-reported due to lack of recognition, misdiagnosis, and mild clinical presentation. Most patients are genetically uncharacterized as the diagnostic confirmation of PAM has traditionally not included a genetic analysis. Genetic testing may in the future be the preferred tool for diagnostics instead of invasive methods. This systematic review aims to provide an overview of the growing knowledge of PAM genetics. Rare variants in SLC34A2 are found in almost all genetically tested patients. So far, 34 allelic variants have been identified in at least 68 patients. A majority of these are present in the homozygous state; however, a few are found in the compound heterozygous form. Most of the allelic variants involve only a single nucleotide. Half of the variants are either nonsense or frameshifts, resulting in premature termination of the protein or decay of the mRNA. There is currently no cure for PAM, and the only effective treatment is lung transplantation. Management is mainly symptomatic, but an improved understanding of the underlying pathophysiology will hopefully result in development of targeted treatment options. More standardized data on PAM patients, including a genetic diagnosis covering larger international populations, would support the design and implementation of clinical studies to the benefit of patients. Further genetic characterization and understanding of how the molecular changes influence disease phenotype will hopefully allow earlier diagnosis and treatment of the disease in the future.