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Background: Prior observational studies have suggested a potential direct link between psoriasis (PSO) and interstitial lung disease (ILD). Consequently, we applied Mendelian randomization (MR) to further evaluate the bidirectional causal relationships between PSO and its different phenotypes [psoriatic arthritis (PSA)/psoriasis vulgaris (PSV)] and ILD., Methods: Data regarding PSO/PSA/PSV and ILD were sourced from publicly accessible genome-wide association studies (GWAS) databases, focusing on European populations. We used five algorithms- MR Egger, weighted median, inverse-variance weighted (IVW), simple mode, and weighted mode- to evaluate the causal relationships between PSO/PSA/PSV and ILD, with a primary emphasis on the IVW method., Results: The analysis indicated a potential association between PSA and an elevated risk of ILD [IVW odds ratio (OR): 1.035 (95% CI 1.008, 1.064; P = 0.012)], with no evidence of a direct relationship between total PSO and PSV with ILD. Conversely, no substantial evidence emerged from the reverse MR analysis to suggest that ILD significantly affects total PSO or the specific PSA/PSV phenotypes., Conclusion: Our findings provide genetic evidence supporting the notion that PSA may be a contributory risk factor for ILD. Further investigations are warranted to explore the underlying mechanisms of this potential causal relationship between PSA and ILD., (© 2024. The Author(s).)

Background: Gain-of-function mutations in STING1 (also known as TMEM173) which result in constitutive activation of STING, have been reported to cause STING-associated vasculopathy with onset in infancy (SAVI). Although a wider spectrum of associated manifestations and perturbations in disease onset have been observed since its description, the genotype-phenotype correlations are not definite, and there is no established treatment protocol for SAVI., Case Presentation: Herein, we report a kindred, heterozygous STING mutation (p.V155M) in which the 2-year-old proband suffered from severe interstitial lung disease (ILD) while her father was initially misdiagnosed with connective tissue disease associated with ILD at an adult age. Baricitinib was initiated after the diagnosis of SAVI in the proband combined with steroids, and during the 14-month follow-up, the respiratory symptoms were improved. However, as the improvement of laboratory indicators was limited, especially in autoimmune indices, and the lung CT images remained unaltered, it seems that JAK1/2 inhibition was unsatisfactory in completely controlling the inflammation of the disease in our study., Conclusions: Baricitinib was shown to elicit some effect on the ILD but failed to control the inflammation of the disease completely. Further exploration of JAK inhibitors or other therapeutic strategies are needed to more optimally treat this inflammatory disease., (© 2023. The Author(s).)

Background: Immunosuppressive and anti-cytokine treatment may have a protective effect for patients with COVID-19. Understanding the immune cell states shared between COVID-19 and other inflammatory diseases with established therapies may help nominate immunomodulatory therapies., Methods: To identify cellular phenotypes that may be shared across tissues affected by disparate inflammatory diseases, we developed a meta-analysis and integration pipeline that models and removes the effects of technology, tissue of origin, and donor that confound cell-type identification. Using this approach, we integrated > 300,000 single-cell transcriptomic profiles from COVID-19-affected lungs and tissues from healthy subjects and patients with five inflammatory diseases: rheumatoid arthritis (RA), Crohn's disease (CD), ulcerative colitis (UC), systemic lupus erythematosus (SLE), and interstitial lung disease. We tested the association of shared immune states with severe/inflamed status compared to healthy control using mixed-effects modeling. To define environmental factors within these tissues that shape shared macrophage phenotypes, we stimulated human blood-derived macrophages with defined combinations of inflammatory factors, emphasizing in particular antiviral interferons IFN-beta (IFN-β) and IFN-gamma (IFN-γ), and pro-inflammatory cytokines such as TNF., Results: We built an immune cell reference consisting of > 300,000 single-cell profiles from 125 healthy or disease-affected donors from COVID-19 and five inflammatory diseases. We observed a CXCL10+ CCL2+ inflammatory macrophage state that is shared and strikingly abundant in severe COVID-19 bronchoalveolar lavage samples, inflamed RA synovium, inflamed CD ileum, and UC colon. These cells exhibited a distinct arrangement of pro-inflammatory and interferon response genes, including elevated levels of CXCL10, CXCL9, CCL2, CCL3, GBP1, STAT1, and IL1B. Further, we found this macrophage phenotype is induced upon co-stimulation by IFN-γ and TNF-α., Conclusions: Our integrative analysis identified immune cell states shared across inflamed tissues affected by inflammatory diseases and COVID-19. Our study supports a key role for IFN-γ together with TNF-α in driving an abundant inflammatory macrophage phenotype in severe COVID-19-affected lungs, as well as inflamed RA synovium, CD ileum, and UC colon, which may be targeted by existing immunomodulatory therapies.

Background: Pulmonary surfactant is a complex mixture of lipids and specific proteins that stabilizes the alveoli at the end of expiration. Mutations in the gene coding for the triphosphate binding cassette transporter A3 (ABCA3), which facilitates the transfer of lipids to lamellar bodies, constitute the most frequent genetic cause of severe neonatal respiratory distress syndrome and chronic interstitial lung disease in children. Hydroxychloroquine can be used as an effective treatment for this rare severe condition., Case Presentation: We report a late preterm Bosnian baby boy (36 weeks) who suffered from a severe form of respiratory distress syndrome with poor response to intensive conventional management and whole exome sequencing revealed homozygous ABCA3 mis-sense mutation. The baby showed remarkable improvement of the respiratory condition after the initiation of Hydroxychloroquine, Azithromycin and Corticosteroids with the continuation of Hydroxychloroquine as a monotherapy till after discharge from the hospital., Conclusion: Outcome in patients with ABCA3 mutations is variable ranging from severe irreversible respiratory failure in early infancy to chronic interstitial lung disease in childhood (ChILD) usually with the need for lung transplantation in many patients surviving this rare disorder. Hydroxychloroquine through its anti-inflammatory effects or alteration of intra-cellular metabolism may have an effect in treating cases of ABCA3 gene mutations.

Background: Systemic sclerosis (SSc) is an acquired autoimmune disorder characterized by excessive accumulation of collagen and progressive tissue fibrosis. Although interstitial lung disease (ILD) complicates the majority of SSc patients and is the leading cause of death, its pathogenesis remains largely unclear. In the current study, we aimed to evaluate the role of microRNAs in SSc-ILD., Methods: miRNA expression patterns were assessed by miRNA array and real-time PCR from serum and PBMCs of SSc-ILD patients and healthy controls. Bleomycin-induced SSc-ILD mouse model was used to verify the miRNA expression in the lung tissue. The function of miRNAs in pulmonary fibroblasts was assessed using miRNA inhibitors, and mimics., Results: miR-320a was significantly downregulated in both SSc-ILD patients and mouse models. The inhibition or overexpression of miR-320a in human pulmonary fibroblasts significantly affected the protein expression of type I collagen. Luciferase reporter assay, RT-PCR, and western blot analysis identified TGFBR2 and IGF1R as direct targets of miR-320a. Upon TGF-β stimulation, the expression of miR-320a and collagen genes were significantly upregulated., Conclusion: miR-320a, together with its target genes, TGFBR2 and IGF1R, constituted a complex regulatory network, and played an important role in the fibrotic process of SSc-ILD. Investigation of more detailed mechanisms of miR-320a-mediated regulation of collagen expression may provide new therapeutic strategies for SSc-ILD.

Background: Interstitial lung diseases (ILDs), a diverse group of diffuse lung diseases, mainly affect the lung parenchyma. The low-throughput 'omics' technologies (genomics, transcriptomics, proteomics) and relative drug information have begun to reshaped our understanding of ILDs, whereas, these data are scattered among massive references and are difficult to be fully exploited. Therefore, we manually mined and summarized these data at a database (ILDGDB, http://ildgdb.org/ ) and will continue to update it in the future., Main Body: The current version of ILDGDB incorporates 2018 entries representing 20 ILDs and over 600 genes obtained from over 3000 articles in four species. Each entry contains detailed information, including species, disease type, detailed description of gene (e.g. official symbol of gene), and the original reference etc. ILDGDB is free, and provides a user-friendly web page. Users can easily search for genes of interest, view their expression pattern and detailed information, manage genes sets and submit novel ILDs-gene association., Conclusion: The main principle behind ILDGDB's design is to provide an exploratory platform, with minimum filtering and interpretation, while making the presentation of the data very accessible, which will provide great help for researchers to decipher gene mechanisms and improve the prevention, diagnosis and therapy of ILDs.

Background: Childhood interstitial lung diseases (ILD) (chILD) refer to a rare heterogeneous group of disorders. Global collaborations have been working on the etiologies and classification scheme of chILD. With the development of medical technologies, some new diseases were identified to be associated with chILD and its etiologic spectrum is expanding. The aim of this study is to describe the etiologic spectrum of chILD in children older than 2 years of age and summarize the approaches to diagnosis of chILD., Methods: We made a retrospective analysis of children older than 2 years of age with chILD who referred to Beijing Children's Hospital from 21 provinces all over China from 2013 to 2018. After excluding pulmonary infection, congenital heart disease, bronchopulmonary dysplasia, bronchiolitis obliterans and bronchiectasis, 133 patients were included and categorized by etiology. Clinical manifestations, high-resolution computed tomography, laboratory data, genetic data and pathologic findings were all collected and reviewed., Results: Systemic disease associated ILD were the most common causes, accounting for 49.6% of the patients, followed by alveolar structure disorder-associated ILD (27%), exposure related ILD (13.5%), and disorders masquerading as ILD (3.8%). In systemic disease associated ILD, in addition to common etiologies such as vasculitis (10.5%) and connective tissue diseases (9.0%), primary immunodeficiency diseases (PID) associated ILD (9.8%), interstitial pneumonia with autoimmune features (6.8%), and metabolic diseases (6.8%) were not rarely found. Some newly reported etiologies such as STING-associated vasculopathy with onset in infancy, COPA syndrome and STAT3 mutation were included in PID associated ILD. Genetic tests contributed to 15% of the diagnoses which mainly distributed in PID associated ILD, metabolic diseases and surfactant dysfunction disorders, and contributed to the final diagnoses more than lung biopsies (13.5%) and biopsies of rashes or other tissues (12%)., Conclusions: This study first demonstrated an etiologic spectrum of chILD in Chinese children older than 2 years of age and summarized the approaches to diagnosis. The etiologic spectrum of chILD is expanding with more genetic etiologies being recognized.

Background: Mutations in the surfactant protein C gene (SFTPC) result in interstitial lung disease (ILD). Our objective was to characterize clinical and genetic spectrum of ILD in Chinese children associated with SFTPC mutations., Methods: Six Chinese children with ILD heterozygous for SFTPC mutations were included. Candidate genes responsible for surfactant dysfunction were sequenced by next-generation sequencing. Subclones of SFTPC with novel mutations were generated and transiently transfected into A549 cells. The functional characterization of mutant surfactant protein C (SP-C) was evaluated by Western blotting and immunofluorescence., Results: The age of onset ranged from 7 days to 15 months. All cases required supplemental oxygen. Failure to thrive (5/6) was the most significant extra-pulmonary manifestation. Hydroxychloroquine was given as the long-term treatment of lung disease in four patients and two of them responded well. Three mutations were identified in six patients: four with I73T, one with D105G, one with Y113H. Mutations in three patients were inherited and three arised de novo. Western blotting revealed totally different band patterns between mutant SP-C (D105G and Y113H) and the wildtype. Immunofluorescence showed mutant SP-C (D105G) was scarcely trafficked to lamellar bodies but localized well to early endosomes, which was in marked contrast to the wildtype protein., Conclusion: SFTPC mutations were an important cause of childhood ILD in Chinese population. I73T was a common SFTPC mutation in Chinese ILD children associated with surfactant protein C mutations.

Introduction: The COPA syndrome is a newly recognized monogenic, autosomal dominant autoimmune disease presenting mostly presenting in childhood. Clinical features include inflammation of the lungs, kidneys, and joints. Approximately twenty-six patients with COPA syndrome worldwide have been investigated all originating from eight families. Patients with this syndrome exhibit heterozygous monogenic missense mutations in the WD40 domain. This domain is a functionally-significant area of the alpha subunit of coatomer-associated protein (COPα) which encodes the coat protein complex I (COPI). The COPI dysfunction is also associated with autoantibody expansion. We report two patients with COPA syndrome., Methods: All testing and molecular genetic analysis were performed after obtaining the informed consent of both the patient and parents. A retrospective chart review was carried out on both the patients. Demographic, clinical and laboratory findings were abstracted from outpatient and inpatient encounters. Pulmonary function tests (PFTs), chest computed tomography (CT) scans, and lung biopsy histopathology reports were also reviewed and summarized., Results: The index case and the father of the child both demonstrated a unique inflammatory pulmonary, arthritis, and renal disease triad starting in early childhood including pulmonary hemorrhage. The two patients had a novel COPA mutation previously undescribed., Conclusions: To date, only four pathological, genetic mutations have been reported that are compatible with COPA syndrome. We here report two patients with COPA syndrome within the same family with a novel COPA gene mutation different than the heterozygous monogenic missense mutations in the WD40 domain and distinct from the clinical phenotypes reported in the literature so far.

Background: Next-generation sequencing of individuals with genetic diseases often detects candidate rare variants in numerous genes, but determining which are causal remains challenging. We hypothesized that the spatial distribution of missense variants in protein structures contains information about function and pathogenicity that can help prioritize variants of unknown significance (VUS) and elucidate the structural mechanisms leading to disease., Results: To illustrate this approach in a clinical application, we analyzed 13 candidate missense variants in regulator of telomere elongation helicase 1 (RTEL1) identified in patients with Familial Interstitial Pneumonia (FIP). We curated pathogenic and neutral RTEL1 variants from the literature and public databases. We then used homology modeling to construct a 3D structural model of RTEL1 and mapped known variants into this structure. We next developed a pathogenicity prediction algorithm based on proximity to known disease causing and neutral variants and evaluated its performance with leave-one-out cross-validation. We further validated our predictions with segregation analyses, telomere lengths, and mutagenesis data from the homologous XPD protein. Our algorithm for classifying RTEL1 VUS based on spatial proximity to pathogenic and neutral variation accurately distinguished 7 known pathogenic from 29 neutral variants (ROC AUC = 0.85) in the N-terminal domains of RTEL1. Pathogenic proximity scores were also significantly correlated with effects on ATPase activity (Pearson r = -0.65, p = 0.0004) in XPD, a related helicase. Applying the algorithm to 13 VUS identified from sequencing of RTEL1 from patients predicted five out of six disease-segregating VUS to be pathogenic. We provide structural hypotheses regarding how these mutations may disrupt RTEL1 ATPase and helicase function., Conclusions: Spatial analysis of missense variation accurately classified candidate VUS in RTEL1 and suggests how such variants cause disease. Incorporating spatial proximity analyses into other pathogenicity prediction tools may improve accuracy for other genes and genetic diseases.

Background: Clinical guidelines specify that diagnosis of interstitial pulmonary fibrosis (IPF) requires identification of usual interstitial pneumonia (UIP) pattern. While UIP can be identified by high resolution CT of the chest, the results are often inconclusive, making surgical lung biopsy necessary to reach a definitive diagnosis (Raghu et al., Am J Respir Crit Care Med 183(6):788-824, 2011). The Envisia genomic classifier differentiates UIP from non-UIP pathology in transbronchial biopsies (TBB), potentially allowing patients to avoid an invasive procedure (Brown et al., Am J Respir Crit Care Med 195:A6792, 2017). To ensure patient safety and efficacy, a laboratory developed test (LDT) must meet strict regulatory requirements for accuracy, reproducibility and robustness. The analytical characteristics of the Envisia test are assessed and reported here., Methods: The Envisia test utilizes total RNA extracted from TBB samples to perform Next Generation RNA Sequencing. The gene count data from 190 genes are then input to the Envisia genomic classifier, a machine learning algorithm, to output either a UIP or non-UIP classification result. We characterized the stability of RNA in TBBs during collection and shipment, and evaluated input RNA mass and proportions on the limit of detection of UIP. We evaluated potentially interfering substances such as blood and genomic DNA. Intra-run, inter-run, and inter-laboratory reproducibility of test results were also characterized., Results: RNA content within TBBs preserved in RNAprotect is stable for up to 14 days with no detectable change in RNA quality. The Envisia test is tolerant to variation in RNA input (5 to 30 ng), with no impact on classifier results. The Envisia test can tolerate dilution of non-UIP and UIP classification signals at the RNA level by up to 60% and 20%, respectively. Analytical specificity studies utilizing UIP and non-UIP samples mixed with genomic DNA (up to 30% relative input) demonstrated no impact to classifier results. The Envisia test tolerates up to 22% of blood contamination, well beyond the level observed in TBBs. The test is reproducible from RNA extraction through to Envisia test result (standard deviation of 0.20 for Envisia classification scores on > 7-unit scale)., Conclusions: The Envisia test demonstrates the robust analytical performance required of an LDT. Envisia can be used to inform the diagnoses of patients with suspected IPF.

Background: Interstitial lung disease (ILD) is frequently associated with rheumatoid arthritis (RA), and is designated RA-associated ILD (RA-ILD). RA-ILD has a large impact on the prognosis of RA. Here, we investigated the micro RNAs (miRNAs) profiles to determine whether they may be useful for diagnosing RA-ILD., Methods: RNA was isolated from plasma samples and cDNA was synthesized. Real-time RT-PCR analysis was performed to evaluate 752 miRNA expression profiles in plasma pools from RA patients with or without RA-ILD. Sixteen selected miRNA levels were analyzed in individual plasmas from 64 RA patients with or without RA-ILD., Results: Expression levels of hsa-miR-214-5p (mean relative expression level ± standard deviation, 8.1 ± 28.2 in RA with ILD, 0.2 ± 0.9 in RA without ILD, P = 0.0156) and hsa-miR-7-5p (56.2 ± 260.4 in RA with ILD, 4.7 ± 11.8 in RA without ILD, P = 0.0362) were higher in RA patients with RA-ILD than in those without. The values of miRNA index (214, 7) generated from hsa-miR-214-5p and hsa-miR-7-5p for ILD were significantly elevated in RA patients with RA-ILD compared with those without (0.122 ± 0.332 in RA with ILD, 0.006 ± 0.013 in RA without ILD, P = 0.0010). The area under the curve value of the receiver operating characteristic curve for the miRNA index (214, 7) was 0.740., Conclusions: To the best of our knowledge, this is the first report of miRNA profiles in RA-ILD. The expression levels of hsa-miR-214-5p and hsa-miR-7-5p were increased in RA with ILD.

Background: Integrin α3 (ITGA3) gene mutations are associated with Interstitial Lung disease, Nephrotic syndrome and Epidermolysis bullosa (ILNEB syndrome). To date only six patients are reported: all carried homozygous ITGA3 mutations and presented a dramatically severe phenotype leading to death before age 2 years, from multi-organ failure due to interstitial lung disease and congenital nephrotic syndrome. The involvement of skin and cutaneous adnexa was variable with sparse hair and nail dysplasia combined or not to skin lesions ranging from skin fragility to epidermolysis bullosa-like blistering., Results: We report on two siblings of 13 and 9 years born to non-consanguineous healthy parents, who display growth delay, severe pulmonary fibrosis with fatigue, dyspnea on exertion and wheezing, atrophic skin with erythematosus lesions, rare eyelashes/eyebrows and pachyonychia. By exome sequencing, we identified two unreported ITGA3 missense mutations, c.373G>A (p.(G125R)) in exon 3 and c.821G>A (p.(R274Q)) in exon 6, affecting highly conserved residues in the integrin α3 extracellular N-terminal β-propeller domain. Homology modelling of α3β1 heterodimer fragment, encompassing the mutation sites, showed that G125 plays a pivotal structural role in the β-propeller, while R274 might prevent the interaction between integrin and urokinase complex., Conclusion: We report a variant of ILNEB syndrome in two siblings differing from the previously reported patients in the lack of nephrotic impairment and survival beyond childhood. Our siblings are the first reported compound heterozygous for ITGA3 mutations; this state as well as the hypomorphic nature of their p.(R274Q) mutation likely account for their survival.

Background: Monoallelic mutations of the Surfactant Protein C gene (SFTPC) are associated with Interstitial Lung Disease in children. I73T is the most common mutation, accounting for 30 % of all cases reported., Case Presentation: We describe three patients carrying the same I73T SPC mutation with very different phenotypes, clinical course (ranging from mild respiratory symptoms to death for respiratory failure) and outcome., Conclusions: The disease mechanisms associated with SP-C mutations suggest that the combination of individual genetic background and environmental factors contribute largely to the wide variability of clinical expression. Infants, children and adults with ILD of unknown etiology should be investigated for SP-C genetic abnormalities.

Background: Surfactant metabolism disorders may result in diffuse lung disease in children., Case Presentation: We report a 3-years-old boy with dry cough, progressive hypoxemia, dyspnea and bilateral ground glass opacities at chest high-resolution computed tomography (HRCT) who had no variants in genes encoding surfactant proteins or transcription factors. Lung histology strongly suggested an abnormality of surfactant protein. A 7-month course of pulse intravenous high-dose methylprednisolone plus oral hydroxychloroquine and azithromycin led to gradual weaning from oxygen and oral steroids, and to improvement of cough and dyspnea. Over the follow-up period, hydroxychloroquine and azithromycin were not withdrawn as cough and dyspnea re-appeared at each attempt and disappeared at re-start. At 6 years of age chest HRCT still appeared unchanged, but clinical symptoms or signs were absent., Conclusions: In children suspected of inborn errors of pulmonary surfactant metabolism who do not have a recognized genetic mutation, lung biopsy with consistent histology may help physicians to address the definitive diagnosis.

Background: Evidence suggests that individuals with interstitial lung abnormalities (ILA) on a chest computed tomogram (CT) may have an increased risk to develop a clinically significant interstitial lung disease (ILD). Although methods used to identify individuals with ILA on chest CT have included both automated quantitative and qualitative visual inspection methods, there has been not direct comparison between these two methods. To investigate this relationship, we created lung density metrics and compared these to visual assessments of ILA., Methods: To provide a comparison between ILA detection methods based on visual assessment we generated measures of high attenuation areas (HAAs, defined by attenuation values between -600 and -250 Hounsfield Units) in >4500 participants from both the COPDGene and Framingham Heart studies (FHS). Linear and logistic regressions were used for analyses., Results: Increased measures of HAAs (in ≥ 10 % of the lung) were significantly associated with ILA defined by visual inspection in both cohorts (P < 0.0001); however, the positive predictive values were not very high (19 % in COPDGene and 13 % in the FHS). In COPDGene, the association between HAAs and ILA defined by visual assessment were modified by the percentage of emphysema and body mass index. Although increased HAAs were associated with reductions in total lung capacity in both cohorts, there was no evidence for an association between measurement of HAAs and MUC5B promoter genotype in the FHS., Conclusion: Our findings demonstrate that increased measures of lung density may be helpful in determining the severity of lung volume reduction, but alone, are not strongly predictive of ILA defined by visual assessment. Moreover, HAAs were not associated with MUC5B promoter genotype.

Idiopathic pulmonary fibrosis (IPF) is the prototype of a large and heterogeneous group of pulmonary disorders, mainly chronic and progressive, usually known as interstitial lung disease (ILD). Over the last few decades, IPF has been increasingly recognized as a major unmet medical need in respiratory medicine and has become the focus of intense research activity. This is due to the fact that IPF incidence is increasing worldwide, with rates (and unfortunately prognosis) which are very similar to those of many forms of cancer. Basic and clinical research on IPF has been enormously advancing over the last few decades, culminating in the recent discovery of two safe and effective drugs, now finally made available to patients. For all these reasons, missing a diagnosis of IPF is not acceptable anymore and there is a need for spreading the knowledge about IPF across various specialties of medicine globally. In this context, this article collection in BMC Medicine contributes to the ultimate goal of early identification and better management of patients with ILD, and IPF in particular, worldwide.

Idiopathic pulmonary fibrosis is a diffuse parenchymal lung disease of unknown cause. The natural history of disease can vary considerably, making it difficult to predict the clinical trajectory for an individual patient. Accurate prognostication is desirable for clinical management as well as for cohort enrichment in clinical trials of therapeutics. Clinical and biomarker models of disease behavior have been developed to improve prognostication in idiopathic pulmonary fibrosis, with moderate predictive capabilities. Integrated prediction models that combine both clinical and biomarker variables will improve prognostication for patients and improved cohort enrichment strategies for clinical trials. This goal may be best achieved through collaborative patient registries with prospectively collected biological samples that allow for characterization of disease behavior in idiopathic pulmonary fibrosis.

Background: GATA-2 transcription factor deficiency has recently been described in patients with a propensity towards myeloid malignancy associated with other highly variable phenotypic features: chronic leukocytopenias (dendritic cell-, monocyto-, granulocyto-, lymphocytopenia), increased susceptibility to infections, lymphatic vasculature abnormalities, and sensorineural deafness. Patients often suffer from opportunistic respiratory infections; chronic pulmonary changes have been found in advanced disease., Case Presentation: We present a case of a 17-year-old previously healthy Caucasian male who was admitted to the hospital with fever, malaise, headache, cough and dyspnea. A chest X-ray revealed bilateral interstitial infiltrates and pneumonia was diagnosed. Despite prompt clinical improvement under antibiotic therapy, interstitial changes remained stable. A high resolution computer tomography showed severe diffuse parenchymal lung disease, while the patient's pulmonary function tests were normal and he was asymptomatic. Lung tissue biopsy revealed chronic reparative and resorptive reaction with organizing vasculitis. At the time of the initial presentation to the hospital, serological signs of acute infection with Epstein-Barr virus (EBV) were present; EBV viremia with atypical serological response persisted during two-year follow up. No other infectious agents were found. Marked monocytopenia combined with B-cell lymphopenia led to a suspicion of GATA-2 deficiency. Diagnosis was confirmed by detection of the previously published heterozygous mutation in GATA2 (c.1081 C > T, p.R361C). The patient's brother and father were both carriers of the same genetic defect. The brother had no clinically relevant ailments despite leukocyte changes similar to the index patient. The father suffered from spondylarthritis, and apart from B-cell lymphopenia, no other changes within the leukocyte pool were seen., Conclusion: We conclude that a diagnosis of GATA-2 deficiency should be considered in all patients with diffuse parenchymal lung disease presenting together with leukocytopenia, namely monocyto-, dendritic cell- and B-lymphopenia, irrespective of severity of the clinical phenotype. Genetic counseling and screening for GATA2 mutations within the patient's family should be provided as the phenotype is highly variable and carriers without apparent immunodeficiency are still in danger of developing myeloid malignancy. A prompt recognition of this rare condition helps to direct clinical treatment strategies and follow-up procedures.

EIA (Equine Infectious Anemia) is a blood-borne disease primarily transmitted by haematophagous insects or needle punctures. Other routes of transmission have been poorly explored. We evaluated the potential of EIAV (Equine Infectious Anemia Virus) to induce pulmonary lesions in naturally infected equids. Lungs from 77 EIAV seropositive horses have been collected in Romania and France. Three types of lesions have been scored on paraffin-embedded lungs: lymphocyte infiltration, bronchiolar inflammation, and thickness of the alveolar septa. Expression of the p26 EIAV capsid (CA) protein has been evaluated by immunostaining. Compared to EIAV-negative horses, 52% of the EIAV-positive horses displayed a mild inflammation around the bronchioles, 22% had a moderate inflammation with inflammatory cells inside the wall and epithelial bronchiolar hyperplasia and 6.5% had a moderate to severe inflammation, with destruction of the bronchiolar epithelium and accumulation of smooth muscle cells within the pulmonary parenchyma. Changes in the thickness of the alveolar septa were also present. Expression of EIAV capsid has been evidenced in macrophages, endothelial as well as in alveolar and bronchiolar epithelial cells, as determined by their morphology and localization. To summarize, we found lesions of interstitial lung disease similar to that observed during other lentiviral infections such as FIV in cats, SRLV in sheep and goats or HIV in children. The presence of EIAV capsid in lung epithelial cells suggests that EIAV might be responsible for the broncho-interstitial damages observed.

Background: Interstitial lung diseases (ILDs) in children represent a heterogeneous group of rare respiratory disorders that affect the lung parenchyma. After the launch of the French Reference Centre for Rare Lung Diseases (RespiRare®), we created a national network and a web-linked database to collect data on pediatric ILD., Methods: Since 2008, the database has been set up in all RespiRare® centres. After patient's parents' oral consent is obtained, physicians enter the data of children with ILD: identity, social data and environmental data; specific aetiological diagnosis of the ILD if known, genetics, patient visits to the centre, and all medical examinations and tests done for the diagnosis and/or during follow up. Each participating centre has a free access to his own patients' data only, and cross-centre studies require mutual agreement. Physicians may use the system as a daily aid for patient care through a web-linked medical file, backed on this database., Results: Data was collected for 205 cases of ILD. The M/F sex ratio was 0.9. Median age at diagnosis was 1.5 years old [0-16.9]. A specific aetiology was identified in 149 (72.7%) patients while 56 (27.3%) cases remain undiagnosed. Surfactant deficiencies and alveolar proteinosis, haemosiderosis, and sarcoidosis represent almost half of the diagnoses. Median length of follow-up is 2.9 years [0-17.2]., Conclusions: We introduce here the French network and the largest national database in pediatric ILDs. The diagnosis spectrum and the estimated incidence are consistent with other European databases. An important challenge will be to reduce the proportion of unclassified ILDs by a standardized diagnosis work-up. This database is a great opportunity to improve patient care and disease pathogenesis knowledge. A European network including physicians and European foundations is now emerging with the initial aim of devising a simplified European database/register as a first step to larger European studies.

Background: Surfactant protein C (SP-C) is important for the function of pulmonary surfactant. Heterozygous mutations in SFTPC, the gene encoding SP-C, cause sporadic and familial interstitial lung disease (ILD) in children and adults. Mutations mapping to the BRICHOS domain located within the SP-C proprotein result in perinuclear aggregation of the proprotein. In this study, we investigated the effects of the mutation A116D in the BRICHOS domain of SP-C on cellular homeostasis. We also evaluated the ability of drugs currently used in ILD therapy to counteract these effects., Methods: SP-CA116D was expressed in MLE-12 alveolar epithelial cells. We assessed in vitro the consequences for cellular homeostasis, immune response and effects of azathioprine, hydroxychloroquine, methylprednisolone and cyclophosphamide., Results: Stable expression of SP-CA116D in MLE-12 alveolar epithelial cells resulted in increased intracellular accumulation of proSP-C processing intermediates. SP-CA116D expression further led to reduced cell viability and increased levels of the chaperones Hsp90, Hsp70, calreticulin and calnexin. Lipid analysis revealed decreased intracellular levels of phosphatidylcholine (PC) and increased lyso-PC levels. Treatment with methylprednisolone or hydroxychloroquine partially restored these lipid alterations. Furthermore, SP-CA116D cells secreted soluble factors into the medium that modulated surface expression of CCR2 or CXCR1 receptors on CD4+ lymphocytes and neutrophils, suggesting a direct paracrine effect of SP-CA116D on neighboring cells in the alveolar space., Conclusions: We show that the A116D mutation leads to impaired processing of proSP-C in alveolar epithelial cells, alters cell viability and lipid composition, and also activates cells of the immune system. In addition, we show that some of the effects of the mutation on cellular homeostasis can be antagonized by application of pharmaceuticals commonly applied in ILD therapy. Our findings shed new light on the pathomechanisms underlying SP-C deficiency associated ILD and provide insight into the mechanisms by which drugs currently used in ILD therapy act.

Pulmonary fibrosis develops in Hermansky-Pudlak syndrome (HPS) types 1 and 4. Limited information is available about lung disease in HPS type 2 (HPS-2), which is characterized by abnormal function of the adaptor protein-3 (AP-3) complex. To define lung disease in HPS-2, one child and two adults with HPS-2 were evaluated at the National Institutes of Health on at least two visits, and another child was evaluated at the University of Texas Health Science Center San Antonio. All four subjects with HPS-2 had findings of interstitial lung disease (ILD) on a high-resolution computed tomography scan of the chest. The predominant feature was ground glass opacification. Subject 1, a 14-year-old male, and subject 4, a 4-year-old male, had severe ILD, pulmonary fibrosis, secondary pulmonary hypertension and recurrent lung infections. Lung biopsy performed at 20 months of age in subject 1 revealed interstitial fibrosis and prominent type II pneumocyte hyperplasia without lamellar body enlargement. Subject 2, a 27-year-old male smoker, had mild ILD. Subject 3, a 22-year-old male nonsmoker and brother of subject 2, had minimal ILD. Severe impairment of gas exchange was found in subjects 1 and 4 and not in subjects 2 or 3. Plasma concentrations of transforming growth factor-β1 and interleukin-17A correlated with severity of HPS-2 ILD. These data show that children and young adults with HPS-2 and functional defects of the AP-3 complex are at risk for ILD and pulmonary fibrosis.

Background: The molecular pathways involved in the interstitial lung diseases (ILDs) are poorly understood. Systems biology approaches, with global expression data sets, were used to identify perturbed gene networks, to gain some understanding of the underlying mechanisms, and to develop specific hypotheses relevant to these chronic lung diseases., Methods: Lung tissue samples from patients with different types of ILD were obtained from the Lung Tissue Research Consortium and total cell RNA was isolated. Global mRNA and microRNA were profiled by hybridization and amplification-based methods. Differentially expressed genes were compiled and used to identify critical signaling pathways and potential biomarkers. Modules of genes were identified that formed a regulatory network, and studies were performed on cultured cells in vitro for comparison with the in vivo results., Results: By profiling mRNA and microRNA (miRNA) expression levels, we found subsets of differentially expressed genes that distinguished patients with ILDs from controls and that correlated with different disease stages and subtypes of ILDs. Network analysis, based on pathway databases, revealed several disease-associated gene modules, involving genes from the TGF-β, Wnt, focal adhesion, and smooth muscle actin pathways that are implicated in advancing fibrosis, a critical pathological process in ILDs. A more comprehensive approach was also adapted to construct a putative global gene regulatory network based on the perturbation of key regulatory elements, transcription factors and microRNAs. Our data underscores the importance of TGF-β signaling and the persistence of smooth muscle actin-containing fibroblasts in these diseases. We present evidence that, downstream of TGF-β signaling, microRNAs of the miR-23a cluster and the transcription factor Zeb1 could have roles in mediating an epithelial to mesenchymal transition (EMT) and the resultant persistence of mesenchymal cells in these diseases., Conclusions: We present a comprehensive overview of the molecular networks perturbed in ILDs, discuss several potential key molecular regulatory circuits, and identify microRNA species that may play central roles in facilitating the progression of ILDs. These findings advance our understanding of these diseases at the molecular level, provide new molecular signatures in defining the specific characteristics of the diseases, suggest new hypotheses, and reveal new potential targets for therapeutic intervention.

The normal fibrinolytic activity within the alveolar space is suppressed in fibrotic lung diseases in part because of increased levels of plasminogen activator inhibitor-1 (PAI-1). Studies with animals have shown that inhibition of the plasminogen system by PAI-1 increases the generation of pulmonary fibrosis. To determine if a similar relationship occurs in human fibrotic lung diseases, we took advantage of a polymorphism (4G/5G) that occurs in the promoter region of the human PAI-1 gene and influences the expression of PAI-1. We hypothesized that the 4G/4G genotype, because of its association with higher levels of PAI-1, would occur in patients with idiopathic interstitial pneumonia more frequently than in a control population. PAI-1 promoter genotype was determined in 88 well-characterized patients with idiopathic interstitial pneumonia consisting of 62 patients with usual interstitial pneumonia and 26 with nonspecific interstitial pneumonia. DNA was extracted from paraffin-embedded biopsy tissue and the genotype identified by polymerase chain reaction and restriction endonuclease digestion. We found that the distribution of PAI-1 genotypes in the idiopathic interstitial pneumonia population was similar to that of a large control population. However, subgroup analysis showed that patients with nonspecific interstitial pneumonia were more likely than the control population to have the promoter genotype (4G/4G) that is associated with higher levels of PAI-1. A similar pattern in PAI-1 polymorphism was not seen in the usual interstitial pneumonia subgroup. The results of this study support the conclusion that PAl-1 expression influences the development of nonspecific interstitial pneumonia in a similar manner to what occurs in animal models of pulmonary fibrosis. Patients with usual interstitial pneumonia did not show the same relationship with PAl-1 genotype.