The US national registry for childhood interstitial and diffuse lung disease: Report of study design and initial enrollment cohort.

INTRODUCTION: Childhood interstitial and diffuse lung disease (chILD) encompasses a broad spectrum of rare disorders. The Children's Interstitial and Diffuse Lung Disease Research Network (chILDRN) established a prospective registry to advance knowledge regarding etiology, phenotype, natural history, and management of these disorders. METHODS: This longitudinal, observational, multicenter registry utilizes single-IRB reliance agreements, with participation from 25 chILDRN centers across the U.S. Clinical data are collected and managed using the Research Electronic Data Capture (REDCap) electronic data platform. RESULTS: We report the study design and selected elements of the initial Registry enrollment cohort, which includes 683 subjects with a broad range of chILD diagnoses. The most common diagnosis reported was neuroendocrine cell hyperplasia of infancy, with 155 (23%) subjects. Components of underlying disease biology were identified by enrolling sites, with cohorts of interstitial fibrosis, immune dysregulation, and airway disease being most commonly reported. Prominent morbidities affecting enrolled children included home supplemental oxygen use (63%) and failure to thrive (46%). CONCLUSION: This Registry is the largest longitudinal chILD cohort in the United States to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.

Clinical scope and healthcare utilization in childhood interstitial lung disease at a tertiary center.

Childhood interstitial lung disease (chILD) is a heterogeneous group of diffuse lung diseases that can be challenging to diagnose. With relative rarity of individual entities, data are limited on disease prevalence, care patterns, and healthcare utilization. The objective of this study was to evaluate chILD prevalence and review diagnostic and clinical care patterns at our center. A single-center, retrospective cohort study was conducted of patients receiving care at the Children's Hospital of Philadelphia (CHOP) between 1 January 2019 and 31 December 2021. Through query of selected ICD-10 billing codes relevant for chILD and medical chart review, a total of 306 patients were identified receiving pulmonary care during this period. Respiratory symptom onset was documented to have developed before 2 years of age for 40% of cases. The most common diagnostic categories included those with oncologic disease (21.2%), bronchiolitis obliterans (10.1%), and connective tissue disease (9.5%). Genetic testing was performed in 49% of cases, while 36% underwent lung biopsy. Hospitalization at CHOP had occurred for 80.4% of patients, with 45.1% ever hospitalized in an intensive care unit. One-third of children had required chronic supplemental oxygen. Seven (2.3%) patients died during this 3-year period. Collectively, these data demonstrate the scope of chILD and extent of health care utilization at a large volume tertiary care center. This approach to cohort identification and EMR-driven data collection in chILD provides new opportunities for cohort analysis and will inform the feasibility of future studies.

Poor functional status at the time of waitlist for pediatric lung transplant is associated with worse pretransplant outcomes.

BACKGROUND: Whether functional status is associated with survival to pediatric lung transplant is unknown. We hypothesized that completely dependent functional status at waitlist registration, defined using Lansky Play Performance Scale (LPPS), would be associated with worse outcomes. METHODS: Retrospective cohort study of pediatric lung transplant registrants utilizing United Network for Organ Sharing's Standard Transplant Analysis and Research files (2005-2020). Primary exposure was completely dependent functional status, defined as LPPS score of 10-40. Primary outcome was waitlist removal for death/deterioration with cause-specific hazard ratio (CSHR) regression. Subdistribution hazard regression (SHR, Fine and Gray) was used for the secondary outcome of waitlist removal due to transplant/improvement with a competing risk of death/deterioration. Confounders included: sex, age, race, diagnosis, ventilator dependence, extracorporeal membrane oxygenation, year, and listing center volume. RESULTS: A total of 964 patients were included (63.5% ≥ 12 years, 50.2% cystic fibrosis [CF]). Median waitlist days were 95; 20.1% were removed for death/deterioration and 68.2% for transplant/improvement. Completely dependent functional status was associated with removal due to death/deterioration (adjusted CSHR 5.30 [95% CI 2.86-9.80]). This association was modified by age (interaction p = 0.0102), with a larger effect for age ≥12 years, and particularly strong for CF. In the Fine and Gray model, completely dependent functional status did not affect the risk of removal due to transplant/improvement with a competing risk of death/deterioration (adjusted SHR 1.08 [95% CI 0.77-1.49]). CONCLUSIONS: Pediatric lung transplant registrants with the worst functional status had worse pretransplant outcomes, especially for adolescents and CF patients. Functional status at waitlist registration may be a modifiable risk factor to improve survival to lung transplant.

Primary graft dysfunction grade 3 following pediatric lung transplantation is associated with chronic lung allograft dysfunction.

BACKGROUND: Severe primary graft dysfunction (PGD) is associated with the development of bronchiolitis obliterans syndrome (BOS), the most common form of chronic lung allograft dysfunction (CLAD), in adults. However, PGD associations with long-term outcomes following pediatric lung transplantation are unknown. We hypothesized that PGD grade 3 (PGD 3) at 48- or 72-hours would be associated with shorter CLAD-free survival following pediatric lung transplantation. METHODS: This was a single center retrospective cohort study of patients ≤ 21 years of age who underwent bilateral lung transplantation between 2005 and 2019 with ≥ 1 year of follow-up. PGD and CLAD were defined by published criteria. We evaluated the association of PGD 3 at 48- or 72-hours with CLAD-free survival by using time-to-event analyses. RESULTS: Fifty-one patients were included (median age 12.7 years; 51% female). The most common transplant indications were cystic fibrosis (29%) and pulmonary hypertension (20%). Seventeen patients (33%) had PGD 3 at either 48- or 72-hours. In unadjusted analysis, PGD 3 was associated with an increased risk of CLAD or mortality (HR 2.10, 95% CI 1.01-4.37, p=0.047). This association remained when adjusting individually for multiple potential confounders. There was evidence of effect modification by sex (interaction p = 0.055) with the association of PGD 3 and shorter CLAD-free survival driven predominantly by males (HR 4.73, 95% CI 1.44-15.6) rather than females (HR 1.23, 95% CI 0.47-3.20). CONCLUSIONS: PGD 3 at 48- or 72-hours following pediatric lung transplantation was associated with shorter CLAD-free survival. Sex may be a modifier of this association.

Improvement of Refractory Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease with Single-Agent Blockade of IL-1ß and IL-18.

Systemic juvenile idiopathic arthritis associated with interstitial lung disease (SJIA-LD) represents a highly morbid subset of SJIA for which effective therapies are lacking. We report the case of a patient with refractory SJIA-LD who underwent treatment with MAS-825, an investigational bispecific monoclonal antibody targeting IL-1ß and IL-18. MAS-825 treatment was associated with a marked reduction in total IL-18 and free IL-18 in both serum and bronchoalveolar lavage fluid (BAL). Baseline oxygen saturation, exercise tolerance, and quality of life metrics improved after treatment with MAS-825, while pulmonary function testing remained stable. Following treatment, the BAL showed no evidence of pulmonary alveolar proteinosis and inflammatory infiltrates were markedly reduced, reflected by decreased numbers of CD4 T-cells, CD8 T-cells, and macrophages. The patient was able to wean entirely off systemic corticosteroids and other biologics after 10 months of treatment with MAS-825 and experienced no side effects of the drug. This case demonstrates improvement in pulmonary symptoms, lung inflammation, and burden of immunomodulatory therapy after treatment with MAS-825 and suggests that simultaneous targeting of both IL-1ß and IL-18 may be a safe and effective treatment strategy in SJIA-LD.

Extracorporeal membrane oxygenation as a bridge to transplant in neonates with fatal pulmonary conditions: A review.

Neonates with progressive respiratory failure should be referred early for subspecialty evaluation and lung transplantation consideration. ECMO should be considered for patients with severe cardiopulmonary dysfunction and a high likelihood of death while on maximal medical therapy, either in the setting of reversible medical conditions or while awaiting lung transplantation. While ECMO offers hope to neonates that experience clinical deterioration while awaiting transplant, the risks and benefits of this intervention should be considered on an individual basis. Owing to the small number of infant lung transplants performed yearly, large studies examining the outcomes of various bridging techniques in this age group do not exist. Multiple single-centre experiences of transplanted neonates have been described and currently serve as guidance for transplant teams. Future investigation of outcomes specific to neonatal transplant recipients bridged with advanced devices is needed.

Child Interstitial Lung Disease in an Infant with Surfactant Protein C Dysfunction due to c.202G>T Variant (p.V68F).

For newborns suspected having childhood interstitial lung disease (ChILD), the sequencing of genes encoding surfactant proteins is recommended. However, it is still difficult to interpret the clinical significance of those variants found. We report a full-term born female infant who presented with respiratory distress and failure to thrive at 2 months of age and both imaging and lung biopsy were consistent with ChILD. Her genetic test was initially reported as a variant of unknown significance in surfactant protein C (c.202G > T, p.V68F), which was modified later as likely pathogenic after reviewing a report of the same variant as causing ChILD. The infant was placed on noninvasive ventilation and treated with IV Methylprednisolone, Hydroxychloroquine, and Azithromycin but did not show significant clinical and radiological improvement underwent tracheostomy and is awaiting lung transplantation at 8 months of age. The challenges interpreting the genetic results are discussed.

Thoracic growth deficiency in childhood cancer survivors may cause overestimation of lung disease.

INTRODUCTION: Survivors of childhood cancers undergo routine pulmonary function testing as they are at an increased lifetime risk for significant lung disease. However, this population also demonstrates growth abnormalities that could influence the interpretation of these tests, as reference equations are based on standing height. We aim to determine the impact of the relative thoracic growth deficiency in childhood cancer survivors on the interpretation of pulmonary function testing. METHODS: Standing height and upper segment length (USL) in childhood cancer survivors undergoing pulmonary function testing at a single academic center were compared to age-matched historical standards. Additionally, pulmonary function tests were compared to reference values generated from standing height and doubled USL. RESULTS: Data were obtained from 107 cancer survivors. While the subjects demonstrated an overall 6.8% lower standing height vs historical standards, they also demonstrated relative thoracic growth abnormality with a further 9.9% decrement in the ratio USL to standing height. The use of doubled upper segment length as a surrogate measure for standing height in pulmonary function reference equations decreased the number of patients with restrictive lung disease as indicated by spirometry. CONCLUSIONS: Childhood cancer survivors have disproportionately worse thoracic growth deficiency vs appendicular growth deficiency. As a result, their USL is disproportionately short for their standing height, which is most commonly used in pulmonary function testing reference equations. This leads to an increased likelihood in these patients meeting pulmonary function test criteria for restrictive lung disease.

Clinical research study designs: The essentials.

In clinical research, our aim is to design a study which would be able to derive a valid and meaningful scientific conclusion using appropriate statistical methods. The conclusions derived from a research study can either improve health care or result in inadvertent harm to patients. Hence, this requires a well-designed clinical research study that rests on a strong foundation of a detailed methodology and governed by ethical clinical principles. The purpose of this review is to provide the readers an overview of the basic study designs and its applicability in clinical research.

Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline.

BACKGROUND: This document presents the American Thoracic Society clinical practice guidelines for the diagnosis of primary ciliary dyskinesia (PCD). TARGET AUDIENCE: Clinicians investigating adult and pediatric patients for possible PCD. METHODS: Systematic reviews and, when appropriate, meta-analyses were conducted to summarize all available evidence pertinent to our clinical questions. Evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach for diagnosis and discussed by a multidisciplinary panel with expertise in PCD. Predetermined conflict-of-interest management strategies were applied, and recommendations were formulated, written, and graded exclusively by the nonconflicted panelists. Three conflicted individuals were also prohibited from writing, editing, or providing feedback on the relevant sections of the manuscript. RESULTS: After considering diagnostic test accuracy, confidence in the estimates for each diagnostic test, relative importance of test results studied, desirable and undesirable direct consequences of each diagnostic test, downstream consequences of each diagnostic test result, patient values and preferences, costs, feasibility, acceptability, and implications for health equity, the panel made recommendations for or against the use of specific diagnostic tests as compared with using the current reference standard (transmission electron microscopy and/or genetic testing) for the diagnosis of PCD. CONCLUSIONS: The panel formulated and provided a rationale for the direction as well as for the strength of each recommendation to establish the diagnosis of PCD.

Accuracy of Nasal Nitric Oxide Measurement as a Diagnostic Test for Primary Ciliary Dyskinesia. A Systematic Review and Meta-analysis.

RATIONALE: Primary ciliary dyskinesia (PCD) is a rare disorder causing chronic otosinopulmonary disease, generally diagnosed through evaluation of respiratory ciliary ultrastructure and/or genetic testing. Nasal nitric oxide (nNO) measurement is used as a PCD screening test because patients with PCD have low nNO levels, but its value as a diagnostic test remains unknown. OBJECTIVES: To perform a systematic review to assess the utility of nNO measurement (index test) as a diagnostic tool compared with the reference standard of electron microscopy (EM) evaluation of ciliary defects and/or detection of biallelic mutations in PCD genes. DATA SOURCES: Ten databases were searched for reference sources from database inception through July 29, 2016. DATA EXTRACTION: Study inclusion was limited to publications with rigorous nNO index testing, reference standard diagnostic testing with EM and/or genetics, and calculable diagnostic accuracy information for cooperative patients (generally >5 yr old) with high suspicion of PCD. SYNTHESIS: Meta-analysis provided a summary estimate for sensitivity and specificity and a hierarchical summary receiver operating characteristic curve. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess study quality, and Grading of Recommendations Assessment, Development, and Evaluation was used to assess the certainty of evidence. In 12 study populations (1,344 patients comprising 514 with PCD and 830 without PCD), using a reference standard of EM alone or EM and/or genetic testing, summary sensitivity was 97.6% (92.7-99.2) and specificity was 96.0% (87.9-98.7), with a positive likelihood ratio of 24.3 (7.6-76.9), a negative likelihood ratio of 0.03 (0.01-0.08), and a diagnostic odds ratio of 956.8 (141.2-6481.5) for nNO measurements. After studies using EM alone as the reference standard were excluded, the seven studies using an extended reference standard of EM and/or genetic testing showed a summary sensitivity of nNO measurements of 96.3% (88.7-98.9) and specificity of 96.4% (85.1-99.2), with a positive likelihood ratio of 26.5 (5.9-119.1), a negative likelihood ratio of 0.04 (0.01-0.12), and a diagnostic odds ratio of 699.3 (67.4-7256.0). Certainty of the evidence was graded as moderate. CONCLUSIONS: nNO is a sensitive and specific test for PCD in cooperative patients (generally >5 yr old) with high clinical suspicion for this disease. With a moderate level of evidence, this meta-analysis confirms that nNO testing using velum closure maneuvers has diagnostic accuracy similar to EM and/or genetic testing for PCD when cystic fibrosis is ruled out. Thus, low nNO values accompanied by an appropriate clinical phenotype could be used as a diagnostic PCD test, though EM and/or genetics will continue to provide confirmatory information.

Pulmonary alveolar proteinosis and Niemann Pick disease type B: An unexpected combination.

BACKGROUND: Pulmonary involvement in Niemann-Pick disease (NPD) is a common finding, especially in type B. It usually manifests with symptoms of restrictive lung disease appearing in adulthood but showing gradual deterioration over time. Treatment options have been dramatically limited, with whole lung lavage offering only temporary improvement. Pulmonary alveolar proteinosis (PAP) has been previously mentioned as part of lung disease in NPD, but only in rare cases of type C2. This is the first study that reports the coexistence of autoimmune PAP with NPD type B. CASE PRESENTATION: An 8 year old female patient with the diagnosis of NPD type B and a 2-year history of respiratory symptoms, presented with another episode of severe respiratory distress. Chest imaging revealed a "crazy paving pattern", raising concern for PAP. After admission to the intensive care unit and application of non-invasive positive pressure ventilation, a whole lung lavage was performed with return of a milky-appearing proteinaceous fluid. Her status post-lavage was markedly improved, while genetic testing placed the diagnosis of autoimmune PAP. The patient was initiated on inhaled GM-CSF treatment and shows a beneficial outcome to date. CONCLUSIONS: In spite of the patient's symptoms being consistent with NPD type of lung involvement, clinical findings raised the suspicion of an underlying disorder, which surprisingly proved to be PAP. The detection of anti-GM-CSF autoantibodies in our patient allowed the initiation of inhaled GM-CSF treatment, which is likely to prove more beneficial in her prognosis than repeated lung lavages.

Constitutively active signaling by the G protein ßγ-subunit mediates intrinsically increased phosphodiesterase-4 activity in human asthmatic airway smooth muscle cells.

Signaling by the Gßγ subunit of Gi protein, leading to downstream c-Src-induced activation of the Ras/c-Raf1/MEK-ERK1/2 signaling pathway and its upregulation of phosphodiesterase-4 (PDE4) activity, was recently shown to mediate the heightened contractility in proasthmatic sensitized isolated airway smooth muscle (ASM), as well as allergen-induced airway hyperresponsiveness and inflammation in an in vivo animal model of allergic asthma. This study investigated whether cultured human ASM (HASM) cells derived from asthmatic donor lungs exhibit constitutively increased PDE activity that is attributed to intrinsically upregulated Gßγ signaling coupled to c-Src activation of the Ras/MEK/ERK1/2 cascade. We show that, relative to normal cells, asthmatic HASM cells constitutively exhibit markedly increased intrinsic PDE4 activity coupled to heightened Gßγ-regulated phosphorylation of c-Src and ERK1/2, and direct co-localization of the latter with the PDE4D isoform. These signaling events and their induction of heightened PDE activity are acutely suppressed by treating asthmatic HASM cells with a Gßγ inhibitor. Importantly, along with increased Gßγ activation, asthmatic HASM cells also exhibit constitutively increased direct binding of the small Rap1 GTPase-activating protein, Rap1GAP, to the α-subunit of Gi protein, which serves to cooperatively facilitate Ras activation and, thereby, enable enhanced Gßγ-regulated ERK1/2-stimulated PDE activity. Collectively, these data are the first to identify that intrinsically increased signaling via the Gßγ subunit, facilitated by Rap1GAP recruitment to the α-subunit, mediates the constitutively increased PDE4 activity detected in asthmatic HASM cells. These new findings support the notion that interventions targeted at suppressing Gßγ signaling may lead to novel approaches to treat asthma.

Pulmonary complications of childhood cancers.

Pulmonary complications are frequently seen in survivors of childhood cancer, and are due to both disease-related and treatment-related causes. While primary lung cancer is extremely rare in the pediatric population, the lung is a common site for metastatic disease. Furthermore, therapies used to treat the pediatric population can often cause pulmonary toxicity. Specifically, chemotherapy, radiation, hematopoietic stem cell transplant, and surgery can all cause long-term damage to the sensitive lung tissue. These pulmonary sequelae can be further subdivided into acute and late effects.

Pro-asthmatic cytokines regulate unliganded and ligand-dependent glucocorticoid receptor signaling in airway smooth muscle.

To elucidate the regulation of glucocorticoid receptor (GR) signaling under pro-asthmatic conditions, cultured human airway smooth muscle (HASM) cells were treated with proinflammatory cytokines or GR ligands alone and in combination, and then examined for induced changes in ligand-dependent and -independent GR activation and downstream signaling events. Ligand stimulation with either cortisone or dexamethsone (DEX) acutely elicited GR translocation to the nucleus and, comparably, ligand-independent stimulation either with the Th2 cytokine, IL-13, or the pleiotropic cytokine combination, IL-1ß/TNFα, also acutely evoked GR translocation. The latter response was potentiated by combined exposure of cells to GR ligand and cytokine. Similarly, treatment with either DEX or IL-13 alone induced GR phosphorylation at its serine-211 residue (GR(Ser211)), denoting its activated state, and combined treatment with DEX+IL-13 elicited heightened and sustained GR(Ser211) phosphorylation. Interestingly, the above ligand-independent GR responses to IL-13 alone were not associated with downstream GR binding to its consensus DNA sequence or GR transactivation, whereas both DEX-induced GR:DNA binding and transcriptional activity were significantly heightened in the presence of IL-13, coupled to increased recruitment of the transcriptional co-factor, MED14. The stimulated GR signaling responses to DEX were prevented in IL-13-exposed cells wherein GR(Ser211) phosphorylation was suppressed either by transfection with specific serine phosphorylation-deficient mutant GRs or treatment with inhibitors of the MAPKs, ERK1/2 and JNK. Collectively, these novel data highlight a heretofore-unidentified homeostatic mechanism in HASM cells that involves pro-asthmatic cytokine-driven, MAPK-mediated, non-ligand-dependent GR activation that confers heightened glucocorticoid ligand-stimulated GR signaling. These findings raise the consideration that perturbations in this homeostatic cytokine-driven GR signaling mechanism may be responsible, at least in part, for the insensirtivity to glucocorticoid therapy that is commonly seen in individuals with severe asthma.

IL-13-induced changes in endogenous glucocorticoid metabolism in the lung regulate the proasthmatic response.

Endogenous glucocorticoid (GC) activation is regulated by the intracellular GC-activating and -inactivating enzymes 11ß-hydroxysteroid dehydrogenase (11ß-HSD)1 and 11ß-HSD2, respectively, that catalyze interconversion of inert cortisone and its bioactive metabolite cortisol. Because endogenous GCs are critically implicated in suppressing the asthmatic state, this study examined the roles of the 11ß-HSD enzymes in regulating GC activation and bronchoprotection during proasthmatic stimulation. Airway hyperresponsiveness to methacholine and inflammation were assessed in rabbits following inhalation of the proasthmatic/proinflammatory cytokine IL-13 with and without pretreatment with the 11ß-HSD inhibitor carbenoxolone (CBX). Additionally, IL-13-induced changes in 11ß-HSD isozyme expression and GC metabolism were examined in epithelium-intact and -denuded tracheal segments and peripheral lung tissues. Finally, the effects of pretreatment with CBX or 11ß-HSD2-targeted siRNAs were investigated with respect to cortisol prevention of IL-13-induced airway constrictor hyperresponsiveness and eotaxin-3 production by airway epithelial cells. IL-13-exposed rabbits exhibited airway hyperresponsiveness, inflammation, and elevated bronchoalveolar lung fluid levels of eotaxin-3. These responses were inhibited by pretreatment with CBX, suggesting a permissive proasthmatic role for 11ß-HSD2. Supporting this concept, extended studies demonstrated that 1) IL-13-treated tracheal epithelium and peripheral lung tissues exhibit upregulated 11ß-HSD2 activity, 2) the latter impairs cortisone-induced cortisol accumulation and the ability of administered cortisol to prevent both IL-13-induced heightened airway contractility and eotaxin-3 release from epithelial cells, and 3) these proasthmatic responses are prevented by cortisol administration in the presence of 11ß-HSD2 inhibition. Collectively, these data demonstrate that the proasthmatic effects of IL-13 are enabled by impaired endogenous GC activation in the lung that is attributed to upregulation of 11ß-HSD2 in the pulmonary epithelium.

G Protein ßγ-subunit signaling mediates airway hyperresponsiveness and inflammation in allergic asthma.

Since the Gßγ subunit of Gi protein has been importantly implicated in regulating immune and inflammatory responses, this study investigated the potential role and mechanism of action of Gßγ signaling in regulating the induction of airway hyperresponsiveness (AHR) in a rabbit model of allergic asthma. Relative to non-sensitized animals, OVA-sensitized rabbits challenged with inhaled OVA exhibited AHR, lung inflammation, elevated BAL levels of IL-13, and increased airway phosphodiesterase-4 (PDE4) activity. These proasthmatic responses were suppressed by pretreatment with an inhaled membrane-permeable anti-Gßγ blocking peptide, similar to the suppressive effect of glucocorticoid pretreatment. Extended mechanistic studies demonstrated that: 1) corresponding proasthmatic changes in contractility exhibited in isolated airway smooth muscle (ASM) sensitized with serum from OVA-sensitized+challenged rabbits or IL-13 were also Gßγ-dependent and mediated by MAPK-upregulated PDE4 activity; and 2) the latter was attributed to Gßγ-induced direct stimulation of the non-receptor tyrosine kinase, c-Src, resulting in downstream activation of ERK1/2 and its consequent transcriptional upregulation of PDE4. Collectively, these data are the first to identify that a mechanism involving Gßγ-induced direct activation of c-Src, leading to ERK1/2-mediated upregulation of PDE4 activity, plays a decisive role in regulating the induction of AHR and inflammation in a rabbit model of allergic airway disease.