Childhood interstitial lung disease associated with connective tissue disease and immune mediated is the second most common chILD diagnostic category. As knowledge of the molecular and genetic underpinnings of these rare disorders advances, the recognized clinical spectrum of pulmonary manifestations that can be associated with them continues to broaden. This review will focus on chILD and other pulmonary complications associated with primary immune disorders, namely monogenic inborn errors of immunity as well as acquired systemic autoimmune and autoinflammatory diseases. Pulmonary complications, including ILD in these diseases can confer increased risk for morbidity and mortality and can be complex to manage due to the multiple organ systems that can be impacted in these systemic disorders. Thankfully, pulmonologists do not have to work alone. These diseases often have stereotypical patterns of extra-pulmonary features which aid in their recognition. In collaboration with a multidisciplinary team of subspecialists, the pulmonary and other systemic manifestations can be managed effectively together. The goal of this review is to familiarize the reader with the distinct patterns of ILD and associated systemic/immunologic features that are characteristic of monogenic inborn errors of immunity and systemic autoimmune and autoinflammatory diseases. In addition, this review will highlight current, emergent and innovative therapeutic strategies and will underscore the important role of multidisciplinary management to improving outcomes for these patients.

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. 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. We report the study design and some 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 (NEHI), 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%). This Registry is the largest longitudinal chILD cohort in the U.S. to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.

Rationale: As a result of the SARS-CoV-2 pandemic, all pediatric pulmonary fellowship programs conducted virtual interviews for the first time in the Fall of 2020. This study aimed to understand the accuracy of virtual-interview derived-impressions of fellowship programs, as well as applicant preference for future fellowship interview cycles. Methods: A group of pediatric pulmonary fellows and Program Directors designed a REDCap survey. The survey was distributed to all first-year pediatric pulmonary fellows who participated in the 2020-2021 virtual interview season. Results: 23/52 (44%) of first-year pediatric pulmonary fellows completed the survey. 96% were able to form general impressions about fellowship programs during their virtual interviews. 96% reported that generally their fellowship experience matched their virtual-interview derived-impressions. 17 of 19 factors applicants use to rank programs had no statistically significant change (p > 0.05) in impression from virtual interview to fellowship experience. The two factors with a statistically significant (p < 0.05) change in impression were patient care related – volume of ‘bread and butter’ pediatric pulmonary patients and volume of tertiary care pediatric pulmonary patients. 87% prefer some form of in-person interview option in future application cycles. A tiered interview format in which applicants are first invited to a virtual interview day followed by an optional in-person second look day was the most popular preference for future interview cycles (48%). Conclusions: Virtual interviews may provide accurate representations of pediatric pulmonary fellowship programs and applicants prefer some type of in-person interview option in future application cycles.

In recent years, a number of monogenic disorders have been described that are characterized by immune dysregulation. A subset of these ‘primary immune regulatory disorders’ can cause severe interstitial lung disease, often recognized in late childhood or adolescence. Patients presenting to pulmonary clinic may have long and complex medical histories but lack a unifying genetic diagnosis. It is crucial for pulmonologists to recognize features suggestive of multisystem immune dysregulation and to initiate genetic workup, since targeted therapies based on underlying genetics may halt or even reverese pulmonary disease progression. Through such an approach, our center has been able to diagnose and treat a cohort of patients with interstitial lung disease from gene defects that affect immune regulation. Here we present representative cases related to pathogenic mutations in three distinct pathways and summarize disease manifestations and treatment approaches. We conclude with a discussion of our perspective on the outstanding challenges for diagnosing and managing these complex life-threatening and chronic disorders.

Objective: The primary immunodeficiency syndromes of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) haploinsufficiency and lipopolysaccharide-responsive and beige-like anchor protein (LRBA) deficiency present with multisystem immune dysregulation. The aim of this study was to characterize and compare the pulmonary manifestations of these two diseases. Methods: We retrospectively analyzed the pulmonary clinical, radiologic, and histopathologic characteristics of 6 patients with CTLA-4 haploinsufficiency and 4 patients with LRBA deficiency with pulmonary involvement followed at a large tertiary care center. Results: Chronic respiratory symptoms were more frequent in patients with LRBA deficiency versus CTLA-4 haploinsufficiency (4/4 versus 1/6). Cough was the most common respiratory symptom. Abnormalities in pulmonary exam and pulmonary function testing were more frequent in LRBA deficiency (4/4, 2/4) compared to CTLA-4 haploinsufficiency (1/6, 2/6). Chest CT findings included mediastinal lymphadenopathy (4/4 in LRBA deficiency versus 1/4 in CTLA-4 haploinsufficiency), pulmonary nodules (4/4, 3/4), ground-glass opacification (4/4, 3/4), and bronchiectasis (3/4, 1/4). Lymphocytic inflammation, concentrated bronchovasculocentrically and paraseptally, was observed in all patients who had lung biopsies (N=3 with LRBA deficiency; N=3 with CTLA-4 haploinsufficiency). Granulomas were seen in all patients with CTLA-4 haploinsufficiency and in no patients with LRBA deficiency. Conclusion: Despite phenotypic overlap amongst these diseases, LRBA deficiency demonstrated greater severity of pulmonary disease, indicated by respiratory symptoms, pulmonary exam, and intrathoracic radiologic findings. Lymphocytic inflammation is a key histologic feature of both of these disorders. Pediatric pulmonologists should suspect these disorders in the appropriate clinical, radiological, and pathological context to better diagnose and treat these patients.