Wikenheiser‐Brokamp, Kathryn A.

ABSTRACT Objective With regulatory approval of HPV‐specific immunotherapy for recurrent respiratory papillomatosis (RRP) and growing experience with systemic bevacizumab, a management algorithm incorporating these medical treatments is warranted. Data Sources and Methods RRP Foundation (RRPF) Key Opinion Leaders offer a proposed management algorithm for adults with RRP considering published literature and commercial drug availability. Results Preventative HPV vaccination should be considered for all patients. Determination of HPV type and pulmonary imaging are important for contemporary RRP patient care and assist in decision making. Risks and benefits of papilloma debulking as needed versus medical management of RRP must be deliberated on a patient case‐by‐case basis. HPV ‐specific immunotherapy that induces an HPV ‐specific T cell response to target the underlying HPV infection that is the cause of RRP is safe, offers the possibility of durable disease control following a short treatment course and is the recommended first‐line medical treatment for patients who wish to avoid the risks of repeat procedural management. Papilloma disease control with systemic bevacizumab, which carries defined risks and must be continued for clinical benefit is the recommended second‐line medical treatment for patients who do not achieve a complete response with immunotherapy and wish to continue medical management. For patients who elect to be treated with debulking procedures as needed, use of locally‐administered adjuvant should be considered. Conclusion This proposed management algorithm from the RRPF serves as a contemporary resource and information guide for adult patients with RRP and their physicians considering treatment options. Level of Evidence 5

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is driven by human papillomavirus (HPV) low-risk strains and is associated with significant morbidity. While previous studies of 2D cultures have shed light on disease pathogenesis and demonstrated the utility of personalized medicine approaches, monolayer cultures lack the 3D tissue architecture and physiology of stratified, sequentially differentiated mucosal epithelium important in RRP disease pathogenesis. Herein we describe the establishment of JoRRP-derived primary cell populations that retain HPV genomes and viral gene expression in culture. These were directly compared to cells from matched adjacent non-diseased tissue, given the known RRP patient-to-patient variability. JoRRP papilloma versus control cells displayed decreased growth at subconfluency, with a switch to increased growth after reaching confluency, suggesting relative resistance to cell-cell contact and/or differentiation. The same papilloma cells grown as 3D organotypic rafts harbored hyperproliferation as compared to controls, with increased numbers of proliferating basal cells and inappropriately replicating suprabasal cells, mimicking phenotypes in the patient biopsies from which they were derived. These complementary model systems provide novel opportunities to elucidate disease mechanisms at distinct stages in JoRRP progression and to identify diagnostic, prognostic and therapeutic factors to personalize patient management and treatment.

Abstract The diffuse cystic lung diseases have a broad differential diagnosis. A wide variety of pathophysiological processes spanning the spectrum from airway obstruction to lung remodeling can lead to multifocal cyst development in the lung. Although lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis are perhaps more frequently seen in the clinic, disorders such as Birt-Hogg-Dubé syndrome, lymphocytic interstitial pneumonia, follicular bronchiolitis, and light-chain deposition disease are increasingly being recognized. Obtaining an accurate diagnosis can be challenging, and management approaches are highly disease dependent. Unique imaging features, genetic tests, serum studies, and clinical features provide invaluable clues that help clinicians distinguish among the various etiologies, but biopsy is often required for definitive diagnosis. In part II of this review, we present an overview of the diffuse cystic lung diseases caused by lymphoproliferative disorders, genetic mutations, or aberrant lung development and provide an approach to aid in their diagnosis and management.

Abstract The diffuse cystic lung diseases (DCLDs) are a group of pathophysiologically heterogenous processes that are characterized by the presence of multiple spherical or irregularly shaped, thin-walled, air-filled spaces within the pulmonary parenchyma. Although the mechanisms of cyst formation remain incompletely defined for all DCLDs, in most cases lung remodeling associated with inflammatory or infiltrative processes results in displacement, destruction, or replacement of alveolar septa, distal airways, and small vessels within the secondary lobules of the lung. The DCLDs can be broadly classified according to underlying etiology as those caused by low-grade or high-grade metastasizing neoplasms, polyclonal or monoclonal lymphoproliferative disorders, infections, interstitial lung diseases, smoking, and congenital or developmental defects. In the first of a two-part series, we present an overview of the cystic lung diseases caused by neoplasms, infections, smoking-related diseases, and interstitial lung diseases, with a focus on lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis.