Efzofitimod: a novel anti-inflammatory agent for sarcoidosis

Efzofitimod is a first-in-class biologic based on a naturally occurring splice variant of histidyl-tRNA synthetase (HARS) that downregulates immune responses via selective modulation of neuropilin-2 (NRP2). Preclinical data found high expression of NRP2 in sarcoidosis granulomas. Treatment with efzofitimod reduced the granulomatous inflammation induced by P. acnes in an animal model of sarcoidosis. A dose escalating trial of efzofitimod in sarcoidosis with chronic symptomatic pulmonary disease found that treatment with efzofitimod was associated with improved quality of life with a trend towards reduced glucocorticoid use and stable to improved pulmonary function. These studies have led to a large Phase 3 trial of efzofitimod in symptomatic pulmonary sarcoidosis.

Pathogenesis of Pulmonary Calcification and Homologies with Biomineralization in Other Tissues

Lungs often present tissue calcifications and even ossifications, both in the context of high or normal serum calcium levels. Precise mechanisms governing lung calcifications have not been explored. Herein, we emphasize recent advances about calcification processes in other tissues (especially vascular and bone calcifications) and discuss potential sources of calcium precipitates in the lungs, involvement of mineralization promoters and crystallization inhibitors, as well as specific cytokine milieu and cellular phenotypes characteristic for lung diseases, which may be involved in pulmonary calcifications. Further studies are necessary to demonstrate the exact mechanisms underlying calcifications in the lungs, document homologies in biomineralization processes between various tissues in physiological and pathologic conditions, and unravel any locally specific characteristics of mineralization processes that may be targeted to reduce or prevent functionally relevant lung calcifications without negatively affecting the skeleton.

Fatal COVID-19 and Non-COVID-19 Acute Respiratory Distress Syndrome Is Associated with Incomplete Alveolar Type 1 Epithelial Cell Differentiation from the Transitional State without Fibrosis

Acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 and other etiologies results from injury to the alveolar epithelial cell (AEC) barrier resulting in noncardiogenic pulmonary edema, which causes acute respiratory failure; recovery requires epithelial regeneration. During physiological regeneration in mice, type 2 AECs (AEC2s) proliferate, exit the cell cycle, transiently assume a transitional state, then differentiate into type 1 AECs (AEC1s); in humans, persistence of the transitional state is associated with pulmonary fibrosis. It is unknown whether transitional cells emerge and differentiate into AEC1s without fibrosis in human ARDS and why transitional cells differentiate into AEC1s during physiological regeneration but persist in fibrosis. We hypothesized that incomplete but ongoing AEC1 differentiation from transitional cells without fibrosis may underlie persistent barrier permeability and acute respiratory failure in ARDS. Immunostaining of postmortem ARDS lungs revealed abundant transitional cells without fibrosis. They were typically cuboidal or partially spread, sometimes flat, and occasionally expressed AEC1 markers. Immunostaining and/or single-cell RNA sequencing revealed that transitional cells in mouse models of physiological regeneration, ARDS, and fibrosis express markers of cell cycle exit but only in fibrosis express a specific senescence marker. Thus, in severe, fatal early ARDS, AEC1 differentiation from transitional cells is incomplete, underlying persistent barrier permeability and respiratory failure but ongoing without fibrosis; senescence of transitional cells may be associated with pulmonary fibrosis.

Cathepsin K is Superior to HMB45 for the Diagnosis of Pulmonary Lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis (LAM) is a rare cystic lung disease affecting predominantly young women. Classified as a low-grade malignant soft tissue neoplasm from the family of perivascular epithelioid cell (PEC) tumors or PEComas, it is characterized by a proliferation of abnormal smooth muscle-like cells (LAM cells), coexpressing myogenic and melanocytic markers, with HMB45 as the gold-standard immunohistochemical diagnostic marker. Cathepsin K, a papain-like cysteine protease with high matrix degrading activity, is commonly used in the pathologic diagnosis of other PEComa tumors, but there are few data regarding its expression in pulmonary LAM. This study compares the sensitivity of cathepsin K with that of HMB45 as immunohistochemical diagnostic markers for pulmonary LAM. Twenty-one (n=21) specimens of pulmonary LAM were retrieved from the archives of the Department of Pathology of the Cleveland Clinic. All cases were evaluated for protein expression of HMB45 and cathepsin K, on consecutive sections of formalin-fixed, paraffin-embedded tissue. The intensity and the total area of the immunostaining were quantified using an Aperio Scan Scope and analyzed with imaging software (Spectrum). Statistical analysis was performed using GraphPad software. The probability of a positive stained lesion on a transbronchial biopsy for each antibody was calculated. The percentage of LAM cells expressing cathepsin K was significantly higher than for HMB45 and overall expression was statistically significantly higher (P=0.0116). Our findings conclude that cathepsin K is a significantly more sensitive immunohistochemical marker than HMB45 in diagnosing pulmonary LAM.

Characterization of SARS-CoV-2 and host entry factors distribution in a COVID-19 autopsy series

Background

SARS-CoV-2 is a highly contagious virus that causes the disease COVID-19. We have recently reported that androgens regulate the expression of SARS-CoV-2 host entry factors ACE2 and TMPRSS2, and androgen receptor (AR) in lung epithelial cells. We also demonstrated that the transcriptional repression of the AR enhanceosome inhibited SARS-CoV-2 infection in vitro.

Methods

To better understand the various sites of SARS-CoV-2 infection, and presence of host entry factors, we extensively characterized the tissue distribution and localization of SARS-CoV-2 virus, viral replication, and host entry factors in various anatomical sites sampled via autopsy. We applied RNA in-situ-hybridization (RNA-ISH), immunohistochemistry (IHC) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) approaches. We also assessed histopathological changes in SARS-CoV-2 infected tissues.

Results

We detect SARS-CoV-2 virus and viral replication in pulmonary tissues by RNA-ISH and IHC and a variety of non-pulmonary tissues including kidney, heart, liver, spleen, thyroid, lymph node, prostate, uterus, and colon by qRT-PCR. We observe heterogeneity in viral load and viral cytopathic effects among various organ systems, between individuals and within the same patient. In a patient with a history of kidney transplant and under immunosuppressant therapy, we observe an unusually high viral load in lung tissue by RNA-ISH, IHC and qRT-PCR. SARS-CoV-2 virus is also detected in this patent’s kidney, liver and uterus. We find ACE2, TMPRSS2 and AR expression to overlap with the infection sites.

Conclusions

This study portrays the impact of dispersed SARS-CoV-2 infection in diverse organ systems, thereby facilitating avenues for systematic therapeutic approaches.

To understand SARS-CoV-2 infection of human organs, we characterized the tissue distribution of SARS-CoV-2 virus, and the presence of host factors that enable the virus to enter cells, in postmortem tissues from six patients who had COVID-19. We assessed the presence of SARS-CoV-2 viral RNA and the expression of human genes that facilitate virus entry in host cells, using several techniques. We observed that SARS-CoV-2, and factors that facilitate virus entry in host cells, were present in the same location in pulmonary and multiple nonpulmonary tissues, including lung, bronchus, trachea, kidney, heart, liver, spleen, thyroid, lymph node, prostate, uterus, and colon. We also reported changes in the microscopic appearance of SARS-CoV-2 infected tissues at various sites. Such findings will guide future coronavirus biology studies on patients with advanced disease.

Wang et al. characterize the tissue distribution of SARS-CoV-2 viral infection and replication as well as the expression of host cell entry factors in postmortem samples from six patients with COVID-19. They report the co-existence of SARS-CoV-2 infection and host entry factors in multiple pulmonary and non-pulmonary tissues.

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part I: Epidemiology, assessment of extrapulmonary conditions, candidate evaluation, selection criteria, and pathology statements

Patients with connective tissue disease (CTD) and advanced lung disease are often considered suboptimal candidates for lung transplantation (LTx) due to their underlying medical complexity and potential surgical risk. There is substantial variability across LTx centers regarding the evaluation and listing of these patients. The International Society for Heart and Lung Transplantation-supported consensus document on lung transplantation in patients with CTD standardization aims to clarify definitions of each disease state included under the term CTD, to describe the extrapulmonary manifestations of each disease requiring consideration before transplantation, and to outline the absolute contraindications to transplantation allowing risk stratification during the evaluation and selection of candidates for LTx.

Reliability of histopathologic diagnosis of fibrotic interstitial lung disease: an international collaborative standardization project

Background

Current interstitial lung disease (ILD) diagnostic guidelines assess criteria across clinical, radiologic and pathologic domains. Significant interobserver variation in histopathologic evaluation has previously been shown but the specific source of these discrepancies is poorly documented. We sought to document specific areas of difficulty and develop improved criteria that would reduce overall interobserver variation.

Methods

Using an internet-based approach, we reviewed selected images of specific diagnostic features of ILD histopathology and whole slide images of fibrotic ILD. After an initial round of review, we confirmed the presence of interobserver variation among our group. We then developed refined criteria and reviewed a second set of cases.

Results

The initial round reproduced the existing literature on interobserver variation in diagnosis of ILD. Cases which were pre-selected as inconsistent with usual interstitial pneumonia/idiopathic pulmonary fibrosis (UIP/IPF) were confirmed as such by multi-observer review. Cases which were thought to be in the spectrum of chronic fibrotic ILD for which UIP/IPF were in the differential showed marked variation in nearly all aspects of ILD evaluation including extent of inflammation and extent and pattern of fibrosis. A proposed set of more explicit criteria had only modest effects on this outcome. While we were only modestly successful in reducing interobserver variation, we did identify specific reasons that current histopathologic criteria of fibrotic ILD are not well defined in practice.

Conclusions

Any additional classification scheme must address interobserver variation in histopathologic diagnosis of fibrotic ILD order to remain clinically relevant. Improvements to tissue-based diagnostics may require substantial resources such as larger datasets or novel technologies to improve reproducibility. Benchmarks should be established for expected outcomes among clinically defined subgroups as a quality metric.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01522-6.

Postmortem Findings Associated With SARS-CoV-2: Systematic Review and Meta-analysis

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome-associated Coronavirus 2 (SARS-CoV-2), has become a global threat to public health. COVID-19 is more pathogenic and infectious than the prior 2002 pandemic caused by SARS-CoV-1. The pathogenesis of certain disease manifestations in COVID-19 such as diffuse alveolar damage (DAD) are thought to be similar to SARS-CoV-1. However, the exact pathogenesis of COVID-19 related deaths remains poorly understood. The aim of this article was to systematically summarize the rapidly emerging literature regarding COVID-19 autopsies. A meta-analysis was also conducted based on data accrued from preprint and published articles on COVID-19 (n=241 patients) and the results compared with postmortem findings associated with SARS-CoV-1 deaths (n=91 patients). Both autopsy groups included mostly adults of median age 70 years with COVID-19 and 50 years with SARS-CoV-1. Overall, prevalence of DAD was more common in SARS-CoV-1 (100.0%) than COVID-19 (80.9%) autopsies (P=0.001). Extrapulmonary findings among both groups were not statistically significant except for hepatic necrosis (P <0.001), splenic necrosis (P<0.006) and white pulp depletion (P <0.001) that were more common with SARS-CoV-1. Remarkable postmortem findings in association with COVID-19 apart from DAD include pulmonary hemorrhage, viral cytopathic effect within pneumocytes, thromboembolism, brain infarction, endotheliitis, acute renal tubular damage, white pulp depletion of the spleen, cardiac myocyte necrosis, megakaryocyte recruitment, and hemophagocytosis.

Fatal COVID-19 ARDS associated with incomplete AEC1 differentiation from the transitional state without senescence or fibrosis

COVID-19 ARDS is associated with prolonged respiratory failure and high mortality, but the underlying mechanisms are unknown. ARDS results from injury to the alveolar epithelial cell (AEC) barrier; clinical recovery requires epithelial regeneration. During physiologic regeneration, AEC2s proliferate, exit the cell cycle, and transiently assume a transitional state before differentiating into AEC1s; transitional cells persist with ineffectual AEC1 differentiation in pulmonary fibrosis. It is unknown why transitional cells differentiate into AEC1s during physiologic regeneration but persist with ensuing scar in fibrosis and whether incomplete AEC1 differentiation from transitional cells without fibrosis may underlie prolonged respiratory failure in COVID-19 ARDS. Immunostaining of postmortem COVID-19 ARDS lungs revealed abundant transitional cells. They were typically cuboidal or partially spread, occasionally flat, but rarely expressed AEC1 markers. They formed organized monolayers on alveolar septa without fibrosis. Immunostaining and/or meta-analysis of scRNAseq datasets revealed that transitional cells in two mouse models of physiologic regeneration, COVID-19 ARDS, and fibrosis express markers of cell cycle exit but only in fibrosis express a specific senescence marker. These data suggest that in COVID-19 ARDS, physiologic AEC1 differentiation from transitional cells is incomplete, thus underlying prolonged barrier permeability and respiratory failure, but as in physiologic regeneration, is ongoing without fibrosis.

Does histological assessment accurately distinguish separate primary lung adenocarcinomas from intrapulmonary metastases? A study of paired resected lung nodules in 32 patients using a routine next-generation sequencing panel for driver mutations

AIM

Various approaches have been reported for distinguishing separate primary lung adenocarcinomas from intrapulmonary metastases in patients with two lung nodules. The aim of this study was to determine whether histological assessment is reliable and accurate in distinguishing separate primary lung adenocarcinomas from intrapulmonary metastases using routine molecular findings as an adjunct.

METHODS

We studied resected tumour pairs from 32 patients with lung adenocarcinomas in different lobes. In 15 of 32 tumour pairs, next-generation sequencing (NGS) for common driver mutations was performed on both nodules. The remainder of tumour pairs underwent limited NGS, or EGFR genotyping. Tumour pairs with different drivers (or one driver/one wild-type) were classified as molecularly unrelated, while those with identical low-frequency drivers were classified as related. Three pathologists independently and blinded to the molecular results categorised tumour pairs as related or unrelated based on histological assessment.

RESULTS

Of 32 pairs, 15 were classified as related by histological assessment, and 17 as unrelated. Of 15 classified as related by histology, 6 were classified as related by molecular analysis, 4 were unrelated and 5 were indeterminate. Of 17 classified as unrelated by histology, 14 were classified as unrelated by molecular analysis, none was related and 3 were indeterminate. Histological assessment of relatedness was inaccurate in 4/32 (12.5%) tumour pairs.

CONCLUSIONS

A small but significant subset of two-nodule adenocarcinoma pairs is inaccurately judged as related by histological assessment, and can be proven to be unrelated by molecular analysis (driver gene mutations), leading to significant downstaging.

E-Cigarette or Vaping Product Use-associated Lung Injury: Developing a Research Agenda. An NIH Workshop Report

The NHLBI convened a working group on October 23, 2019, to identify the most relevant and urgent research priorities and prevailing challenges in e-cigarette or vaping product use-associated lung injury (EVALI). Experts across multiple disciplines discussed the complexities of the EVALI outbreak, identified research priorities, and recommended strategies to address most effectively its causal factors and improve diagnosis, treatment, and prevention of this disease. Many research priorities were identified, including the need to create national and international registries of patients with EVALI, to track accurately those affected and assess outcomes. The group concluded that biospecimens from subjects with EVALI are urgently needed to help define EVALI pathogenesis and that vaping has disease risks that are disparate from smoking, with the occurrence of EVALI highlighting the importance of broadening e-cigarette research beyond comparators to smoking-related diseases.

Mucinous adenocarcinoma arising in congenital pulmonary airway malformation: clinicopathological analysis of 37 cases

AIMS

Mucinous adenocarcinoma arising in congenital pulmonary airway malformation (CPAM) is a rare complication, with little being known about its natural course. The aims of this article are to describe a series of mucinous adenocarcinomas arising from CPAMs, and present their clinicopathological features, genetics, and clinical outcome.

METHODS AND RESULTS

Thirty-seven cases were collected within a 34-year period, and the subtype of adenocarcinoma and CPAM, tumour location, stage, growth patterns, molecular data and follow-up were recorded. The cohort comprised CPAM type 1 (n = 33) and CPAM type 2 (n = 4). Morphologically, 34 cases were mucinous adenocarcinomas (21 in situ; 13 invasive), and three were mixed mucinous and non-mucinous adenocarcinoma. Seventeen cases showed purely extracystic (intra-alveolar) adenocarcinoma, 15 were mixed intracystic and extracystic, and five showed purely intracystic proliferation. Genetically, nine of 10 cases tested positive for KRAS mutations, four with exon 2 G12V mutation and five with exon 2 G12D mutation. Residual disease on completion lobectomy was observed in two cases, and three cases recurred 7, 15 and 32 years after the original diagnosis. Two patients died of metastatic invasive mucinous adenocarcinoma.

CONCLUSIONS

Most adenocarcinoma that arise in type 1 CPAMs, are purely mucinous, and are early-stage disease. Intracystic proliferation is associated with lepidic growth, an absence of invasion, and indolent behaviour, whereas extracystic proliferation may be associated with more aggressive behaviour and advanced stage. Most cases are cured by lobectomy, and recurrence/residual disease seems to be associated with limited surgery. Long-term follow-up is needed, as recurrence can occur decades later.

The pulmonary pathology of COVID-19

A growing number of international postmortem studies identify acute and organizing diffuse alveolar damage (DAD) as the main pathologic feature of lung injury in patients with COVID-19. Other forms of acute lung injury, including organizing pneumonia, and acute fibrinous and organizing pneumonia are seen. Acute neutrophilic infiltrates have been observed, most frequently as the manifestation of a superimposed bacterial pneumonia. SARS-CoV-2 has been detected in type I and type II pneumocytes and bronchial epithelial cells using electron microscopy, immunohistochemistry, and in situ hybridization, and likewise, viral transcripts were localized with RNA probes in pneumocytes. However, the presence of true viral cytopathic effect seen with light microscopy remains to be defined. Interestingly, vascular changes are frequently observed in association with DAD, which include severe endothelial injury/endothelialitis, hemorrhage, and thrombotic and microangiopathic vasculopathy. Since similar vascular changes also occur in cases of DAD independent of the etiology, whether the vascular pathology in COVID lungs has unique features and represents a separate pathologic process is under investigation.

Primary lung neoplasms presenting as multiple synchronous lung nodules

Multiple synchronous lung nodules are frequently encountered on computed tomography (CT) scanning of the chest and are most commonly either non-neoplastic or metastases from a known primary malignancy. The finding may initiate a search for primary malignancy elsewhere in the body. An exception to this rule, however, is a class of rare primary lung neoplasms that originate from epithelial (pneumocytes and neuroendocrine), mesenchymal (vascular and meningothelial) and lymphoid tissues of the lung. While these rare neoplasms also present as multiple synchronous unilateral or bilateral lung nodules on chest CT, they are often overlooked in favour of more common causes of multiple lung nodules. The correct diagnosis may be suggested by a multidisciplinary team and established on biopsy, performed either as part of routine diagnostic work-up or staging for malignancy. In this review, we discuss clinical presentations, imaging features, pathology findings and subsequent management of these rare primary neoplasms of the lung.

Role of fibroblast growth factor 23 and klotho cross talk in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia that mainly affects the elderly. Several reports have demonstrated that aging is involved in the underlying pathogenic mechanisms of IPF. α-Klotho (KL) has been well characterized as an "age-suppressing" hormone and can provide protection against cellular senescence and oxidative stress. In this study, KL levels were assessed in human plasma and primary lung fibroblasts from patients with idiopathic pulmonary fibrosis (IPF-FB) and in lung tissue from mice exposed to bleomycin, which showed significant downregulation when compared with controls. Conversely, transgenic mice overexpressing KL were protected against bleomycin-induced lung fibrosis. Treatment of human lung fibroblasts with recombinant KL alone was not sufficient to inhibit transforming growth factor-β (TGF-β)-induced collagen deposition and inflammatory marker expression. Interestingly, fibroblast growth factor 23 (FGF23), a proinflammatory circulating protein for which KL is a coreceptor, was upregulated in IPF and bleomycin lungs. To our surprise, FGF23 and KL coadministration led to a significant reduction in fibrosis and inflammation in IPF-FB; FGF23 administration alone or in combination with KL stimulated KL upregulation. We conclude that in IPF downregulation of KL may contribute to fibrosis and inflammation and FGF23 may act as a compensatory antifibrotic and anti-inflammatory mediator via inhibition of TGF-β signaling. Upon restoration of KL levels, the combination of FGF23 and KL leads to resolution of inflammation and fibrosis. Altogether, these data provide novel insight into the FGF23/KL axis and its antifibrotic/anti-inflammatory properties, which opens new avenues for potential therapies in aging-related diseases like IPF.

Calcium sensing receptor in developing human airway smooth muscle

Airway smooth muscle (ASM) regulation of airway structure and contractility is critical in fetal/neonatal physiology in health and disease. Fetal lungs experience higher Ca²⁺ environment that may impact extracellular Ca²⁺ ([Ca²⁺ ]_o ) sensing receptor (CaSR). Well-known in the parathyroid gland, CaSR is also expressed in late embryonic lung mesenchyme. Using cells from 18-22 week human fetal lungs, we tested the hypothesis that CaSR regulates intracellular Ca²⁺ ([Ca²⁺ ]_i ) in fetal ASM (fASM). Compared with adult ASM, CaSR expression was higher in fASM, while fluorescence Ca²⁺ imaging showed that [Ca²⁺ ]_i was more sensitive to altered [Ca²⁺ ]_o . The fASM [Ca²⁺ ]_i responses to histamine were also more sensitive to [Ca²⁺ ]_o (0-2 mM) compared with an adult, enhanced by calcimimetic R568 but blunted by calcilytic NPS2143. [Ca²⁺ ]_i was enhanced by endogenous CaSR agonist spermine (again higher sensitivity compared with adult). Inhibition of phospholipase C (U73122; siRNA) or inositol 1,4,5-triphosphate receptor (Xestospongin C) blunted [Ca²⁺ ]_o sensitivity and R568 effects. NPS2143 potentiated U73122 effects. Store-operated Ca²⁺ entry was potentiated by R568. Traction force microscopy showed responsiveness of fASM cellular contractility to [Ca²⁺ ]_o and NPS2143. Separately, fASM proliferation showed sensitivity to [Ca²⁺ ]_o and NPS2143. These results demonstrate functional CaSR in developing ASM that modulates airway contractility and proliferation.

A 54-Year-Old Man With Anasarca, Dyspnea, and Recurrent Bilateral Pleural Effusions

CASE PRESENTATION

A 54-year-old African-American man presented with 2 years of progressively worsening dyspnea and anasarca. Over the past 6 months he gained 30 lbs with worsening lower extremity, abdominal wall, and scrotal edema. A recent workup for cardiac, renal, and liver disease, including two-dimensional echocardiogram, liver and renal function tests, and abdominal ultrasound, was unremarkable. He reported a 15-pack year history of smoking and quit 3 years ago. Chest radiograph at that time revealed bilateral pleural effusions that were both reportedly milky in appearance when drained by thoracenteses.

Humoral Human Lung Allograft Rejection by Tissue-Restricted Non-HLA Antibodies

A third of lung recipients have preexisting antibodies against nonhuman leukocyte self-antigens (nHAbs) present in the lung tissue. These nHAbs also form de novo in about 70% of patients within 3 years after transplantation. Both preexisting and de novo nHAbs can cause murine lung allograft dysfunction. However, their role in human transplantation remains unclear. We report hyperacute rejection after right lung transplant in a recipient with preexisting nHAbs. The recipient of the left lung from the same donor had an uneventful initial course, but de novo nHAbs developed at 3 weeks, leading to acute humoral rejection. Both patients were successfully treated with antibody-directed therapies.

Pathological Hyaluronan Matrices in Cystic Fibrosis Airways and Secretions

Hyaluronan (HA) has been used in treatment of cystic fibrosis (CF) via a nebulizer and has demonstrated success in clinical outcomes. HA is an important glycosaminoglycan that is cross-linked by heavy chains (HCs) from inter-α-inhibitor during inflammation. HC cross-linked HA (HC-HA) becomes significantly more adhesive for leukocytes than non-cross-linked HA, which can enhance inflammation. Our studies tested the hypothesis that HC-HA is present in CF airways and that altered ratios of HC-HA to its degradation into relatively lower molecular weight HA contribute to the pathophysiology of chronic inflammation in CF. We evaluated the distribution, levels, and size of HC-HA within CF, healthy, and diseased control lung, bronchus, and sputum tissues by histological and biochemical approaches. HC-HA was significantly elevated in CF, with deposits around the pulmonary vasculature, airway submucosa, and in the stroma of the submucosal glands. The increased infiltration of leukocyte populations correlated with the distribution of HC-HA matrices in the airways. Elevated lung tissue HC-HA correlated with decreased HA levels in CF mucus and sputum compared with controls, suggesting that aberrant degradation and cross-linking of HA in lung tissue is a unique feature of CF. The accumulation and degradation of proinflammatory HC-HA in CF lung tissue suggests that aberrant HA catabolism and cross-linking may contribute to chronic inflammation in airway tissues and affect mucus viscosity in CF airways.

Pulmonary Vasculitis: Spectrum of Imaging Appearances

Pulmonary vasculitis is a relatively uncommon disorder, usually manifesting as part of systemic vasculitis. Imaging, specifically computed tomography, is often performed in the initial diagnostic workup. Although the findings in vasculitis can be nonspecific, they can provide important clues in the diagnosis, and guide the clinical team toward the right diagnosis. Radiologists must have knowledge of common and uncommon imaging findings in various vasculitides. Also, radiologists should be able to integrate the clinical presentation and laboratory test findings together with imaging features, so as to provide a meaningful differential diagnosis.

Lymphocytic Interstitial Pneumonia

Lymphocytic interstitial pneumonia (LIP) is a rare lung disease on the spectrum of benign pulmonary lymphoproliferative disorders. LIP is frequently associated with connective tissue diseases or infections. Idiopathic LIP is rare; every attempt must be made to diagnose underlying conditions when LIP is diagnosed. Computed tomography of the chest in patients with LIP may reveal ground-glass opacities, centrilobular and subpleural nodules, and randomly distributed thin-walled cysts. Demonstrating polyclonality with immunohistochemistry is the key to differentiating LIP from lymphoma. The 5-year mortality remains between 33% and 50% and is likely to vary based on the underlying disease process.

A 33-year-old man with multiple bilateral pulmonary pseudoaneurysms

A 33-year-old man, never smoker, presented with acute-onset dyspnea secondary to bilateral pulmonary emboli. Echocardiography at the time revealed a right atrial myxoma, for which he underwent resection, followed by anticipated lifelong therapeutic anticoagulation therapy.

Nodular pulmonary light chain deposition disease: an entity associated with Sjögren syndrome or marginal zone lymphoma

Background

Light chain deposition disease (LCDD) is usually a systemic disorder characterised by non-amyloid monoclonal immunoglobulin light chain deposition in tissues. Localised nodular pulmonary (NP) LCDD is a rare and poorly characterised entity and, owing to the difficulties in diagnosis, limited data are available.

Methods

We investigated the clinical, radiological and pathological characteristics of a series of six confidently diagnosed cases of NPLCDD.

Results

There were three men and three women with ages ranging from 33 to 74 years. In all cases there were single or multiple pulmonary nodules, in one case associated with cysts. Two patients had no previous history of a lymphoproliferative or autoimmune disorder, two had Sjögren syndrome (SS) and two had extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Lung biopsies led to diagnoses of MALT lymphoma in four patients, including both of those with a previous history of lymphoma and one with SS. In five cases the diagnosis was confirmed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) and in one by electron microscopy. There was no evidence of systemic LCDD in any of the cases. Five patients had an indolent course in spite of limited therapeutic intervention while, in the patient who died, the cause of death was related to the spread of the lymphoma and was not due to the pulmonary lesions.

Conclusions

NPLCDD is an indolent disease, in most cases associated with MALT lymphoma or autoimmune disease.

A 70-Year-Old Man With Large Cervical and Mediastinal Lymphadenopathies

We present a case of a 70-year-old man with enlarged mediastinal and cervical lymph nodes that provided interesting radiologic and pathologic observations. The 70-year-old black man was found to have enlarged mediastinal lymph nodes. He had symptoms of atypical chest pain and generalized weakness for 2 weeks prior to the diagnosis. He denied shortness of breath, fever, chills, or night sweats. He was treated for hypertension and onychomycosis. Basic laboratory findings were within normal limits. Pulmonary function tests at the time of presentation showed FEV1, FVC, and FEV1/FVC ratio of 123% predicted, 133% predicted, and 0.7, respectively. Meanwhile, total lung capacity and carbon monoxide diffusing capacity were 103% and 107% predicted, respectively. Two weeks before he presented to our institution, the patient underwent bronchoscopy with transbronchial biopsies of the right lower lobe and endobronchial ultrasound-guided transbronchial needle aspiration of the right hilar lymph nodes.

Hyaluronan and Its Heavy Chain Modification in Asthma Severity and Experimental Asthma Exacerbation

Hyaluronan (HA) is a large (>1500 kDa) polysaccharide of the extracellular matrix that has been linked to severity and inflammation in asthma. During inflammation, HA becomes covalently modified with heavy chains (HC-HA) from inter-α-inhibitor (IαI), which functions to increase its avidity for leukocytes. Our murine model of allergic pulmonary inflammation suggested that HC-HA may contribute to inflammation, adversely effecting lower airway remodeling and asthma severity. Our objective was to characterize the levels of HA and HC-HA in asthmatic subjects and to correlate these levels with asthma severity. We determined the levels and distribution of HA and HC-HA (i) from asthmatic and control lung tissue, (ii) in bronchoalveolar lavage fluid obtained from non-severe and severe asthmatics and controls, and (iii) in serum and urine from atopic asthmatics after an experimental asthma exacerbation. HC-HA distribution was observed (i) in the thickened basement membrane of asthmatic lower airways, (ii) around smooth muscle cells of the asthmatic submucosa, and (iii) around reserve cells of the asthmatic epithelium. Patients with severe asthma had increased HA levels in bronchoalveolar lavage fluid that correlated with pulmonary function and nitric oxide levels, whereas HC-HA was only observed in a patient with non-severe asthma. After an experimental asthma exacerbation, serum HA was increased within 4 h after challenge and remained elevated through 5 days after challenge. Urine HA and HC-HA were not significantly different. These data implicate HA and HC-HA in the pathogenesis of asthma severity that may occur in part due to repetitive asthma exacerbations over the course of the disease.

Coexistent pulmonary granular cell tumor and adenocarcinoma of the lung

We report a case of granular cell tumor (GCT) of the lung with coexistent invasive adenocarcinoma. GCTs are rare tumors and often benign and amenable to local bronchoscopic excision. However, occasionally they are more aggressive and locally infiltrative requiring definitive surgical resection. Our patient had a central and infiltrative GCT, in addition a very small (6 mm) peripheral nodule in the same lobe as the GCT, which after careful examination of the surgical specimen during grossing was found to be an invasive adenocarcinoma. There are a few reports in the literature of GCTs with coexistent bronchogenic cancer. Our case highlights the importance of careful evaluation and exploration of the surgical specimens during grossing of patients with GCTs. In GCT patients presenting with additional pulmonary nodules, a more definitive surgical approach should be considered.

Pulmonary capillary hemangiomatosis associated with connective tissue disease: a report of 4 cases and review of the literature

Pulmonary hypertension (PHTN) can be seen in patients with connective tissue disease (CTD). The typical pathology associated with CTD is interstitial fibrosis and hypertensive pulmonary arteriopathy. We describe 4 patients with CTD and PHTN unexpectedly found to have pulmonary capillary hemangiomatosis (PCH) at explant after lung transplantation or autopsy. Pulmonary capillary hemangiomatosis is defined as a proliferation of capillaries in alveolar walls and can clinically cause PHTN. We detail the pathologic findings of PCH, describe the differential diagnosis, and present a review of the literature on the possible association of PCH with CTD. Although PCH may present clinically as PHTN, it is critical to differentiate between the typical CTD-associated interstitial fibrosis with hypertensive pulmonary arteriopathy and PCH because the treatment is different. We provide the largest case series to date and highlight the need for pathologists to have a high level of suspicion for PCH in patients with CTD.

Another Case of Pulmonary Edema or May Be Not: An Unusual Presentation of Metastatic Melanoma

Melanoma is a tumor of pigment producing cells melanocytes. Malignant melanoma is associated with a high morbidity and mortality because of its widespread and rapid metastasis. Melanoma commonly metastasizes to lung and secondary metastatic pulmonary melanoma is a well known entity. Metastatic melanoma can present with varied pattern of pulmonary involvement ranging from post obstructive pneumonia to atelectasis. However, lung involvement is not known to cause hypoxic respiratory failure. Here, we describe a rare case of metastatic melanoma presenting as an acute respiratory distress syndrome requiring mechanical ventilation.

Severity of neonatal hyperoxia determines structural and functional changes in developing mouse airway

Wheezing is a major long-term respiratory morbidity in preterm infants with and without bronchopulmonary dysplasia. We hypothesized that mild vs. severe hyperoxic exposure in neonatal mice differentially affects airway smooth muscle hypertrophy and resultant airway reactivity. Newborn mice were exposed to 7 days of mild (40% oxygen) or severe (70% oxygen) hyperoxia vs. room air controls. Respiratory system resistance (Rrs), compliance (Crs), and airway reactivity were measured 14 days after oxygen exposure ended under ketamine/xylazine anesthesia. Baseline Rrs increased and Crs decreased in both treatment groups. Methacholine challenge dose dependently increased Rrs and decreased Crs in 40% oxygen-exposed mice, whereas Rrs and Crs responses were similar between 70% oxygen-exposed and normoxic controls. Airway smooth muscle thickness was increased in 40%- but not 70%-exposed mice, whereas collagen increased and both alveolar number and radial alveolar counts decreased after 40% and 70% oxygen. These data indicate that severity of hyperoxia may differentially affect structural and functional changes in the developing mouse airway that contribute to longer-term hyperreactivity. These findings may be important to our understanding of the complex role of neonatal supplemental oxygen therapy in postnatal development of airway responsiveness.

Tumoral MET/HGF expression and MET gene amplification in patients with ALK 2p23 fusion driven lung cancer

11091

Background: MET receptor and its ligand HGF are both promising targets in non-small cell lung cancer (NSCLC) therapy. Crizotinib, a recently approved ALK inhibitor for NSCLC harboring oncogenic ALK 2p23 fusion (ALK+), was initially developed as a bona fide MET inhibitor. The role of MET/HGF pathway in ALK+ NSCLC is still unknown. Methods: The study included 73 NSCLC patients tested for ALK rearrangements at Cleveland Clinic (2000-2012), including 21 ALK+ and 52 ALK-. Immunohistochemistry (IHC) on FFPE tumor tissue was performed for c-MET using a monoclonal CONFIRM antibody (SP44, Ventana) with Ventana Benchmark XT automated immunostainer and for HGF using a polyclonal antibody (R&D) following a manual protocol. IHC scoring was interpreted on a 4-tier system (0, 1+, 2+, 3+). MET gene amplification by MET/Chromosome 7 dual probe in-situ hybridiazation (DISH) (Ventana) was also performed. Statistical analysis was performed using Fisher exact test in JMP. Results: Of the tested tumors, 61 were adenocarcinoma (21 ALK+ and 40 ALK-), 6 squamous cell, 4 large cell and 2 NSCLC-NOS. None received any MET inhibitor prior to tissue collection. MET expression by IHC score 0-3 was: 35%, 33%, 15% and 17% in ALK-, and 5%, 37%, 42% and 16% in ALK+ tumor group, respectively. HGF IHC score 0-3 was 34%, 55%, 11% and 0% in ALK-, and 0%, 63%, 32% and 5% in ALK+ tumor group, respectively. The percentages of high MET or HGF expression (2+ or 3+) were higher in ALK+ group compared to ALK- (58% vs 32%, p=0.06, and 37% vs 11%, p=0.03). The correlation coefficient between MET and HGF expression was 0.48. MET gene amplification by DISH was detected in 15% (7/47) ALK- tumors but 0% (0/15) ALK+ tumors (difference not statistically significant, p=0.18). The correlation coefficient between MET IHC and MET gene amplification was 0.33. Conclusions: MET and HGF expression is commonly seen in NSCLC, with more frequent high expression levels in ALK+ than ALK- tumors. Using a newly developed DISH method, we show that MET gene amplification tend to be less frequent in ALK+ tumor. A prospective study with larger sample size is warranted to further define the role of MET/HGF as biomarkers in the biology of NSCLC with ALK rearrangements and their targeted therapy.

Clinical implications of routine testing for epidermal growth factor receptor (EGFR) mutations in patients with nonsquamous non-small cell lung cancer (NSCLC)

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Background: EGFR mutation (Mut) testing is recommended for all patients (pts) with advanced NSCLC to identify pts who may benefit from front-line EGFR tyrosine kinase inhibitor (TKI) therapy. In July 2010 the Cleveland Clinic initiated reflex EGFR testing of all new diagnoses of nonsquamous NSCLC, prior to which testing was done only by physician request. A retrospective study was designed to review how this change affected clinical practice in a large academic health center. Methods: All pts with NSCLC that had EGFR Mut testing performed at the Cleveland Clinic from 07/2009 to 02/2012 were included (n=287). Pt characteristics, tumor histology and stage, Mut status, treatments, and pt outcomes were collected from electronic medical records. Special attention was given to pts with EGFR Mut+ who received erlotinib (E). Data were analyzed using Fisher’s exact, chi-square and the Wilcoxon rank-sum tests. Results: See Table. Conclusions: Automatic EGFR mutation testing, recommended in an ASCO provisional clinical opinion in April 2011, was feasible in a large academic center and significantly shortened the time between diagnosis and EGFR status becoming available to guide treatment decisions. Although not statistically significant due to the small sample size, there were positive trends towards increased first line usage of E in pts with EGFR Mut+, better performance status, lower rates of E discontinuation due to toxicity, and higher response rate to E in the automatic testing group. There was no difference in overall survival between the two groups. [Table: see text]

Abstract 2374: Tumoral MET expression and plasma HGF level in patients with ALK 2p23 fusion driven lung cancer

Background. MET is the tyrosine kinase receptor for the ligand hepatocyte growth factor (HGF). MET kinase has been identified as a novel promising target in non-small cell lung lung cancer (NSCLC). Crizotinib, a recently FDA-approved ALK inhibitor for NSCLC harboring ALK 2p23 fusion (ALK+), was initially developed as a MET inhibitor. MET expression level is a potential biomarker for response to MET inhibitors. The role of MET/HGF pathway in ALK+ NSCLC is unknown.

Methods. A cohort of 51 NSCLC patients tested for ALK fusion at Cleveland Clinic (2000 to 2012), including 15 ALK(+) and 36 ALK(-) subjects, were included in the study. Immunohistochemistry (IHC) stain against MET was performed using a monoclonal CONFIRM anti-Total c-MET antibody (SP44, Ventana). Staining was performed on a Ventana Benchmark XT automated immunostainer (Ventana Medical Systems). A four-tier (0, 1+, 2+, 3+) scoring system and H-score (the sum of each intensity score x %) were used. Thirteen ALK(+) patients treated on crizotinib therapy were prospectively followed and a total of 32 blood plasma samples were collected (1) prior to crizotinib initiation, (2) during responding period and (3) at disease progression, for HGF level measurement using HGF ELISA kit (R&D). Statistical analysis was performed using Fisher exact test and Wilcoxon rank sum test in JMP.

Results. Of the 51 tumor tested for MET IHC, 39 were adenocarcinoma (15 ALK+ and 24 ALK-), 6 squamous cell, 4 large cell carcinoma and 2 other NSCLC. None received any MET inhibitor when tissue was collected. The percentage of negative MET IHC (score 0 or 1+ in 50% tumor cells) was not statistically significant between ALK(+) and ALK(-) groups (40% vs 30%, p=0.5). The plasma HGF levels in ALK(+) patients varies from undetectable to 14000pg/ml. The median (25th-75th quantiles) level in patients prior to crizotinib therapy (n=5), during responding period (CR/PR/SD, n=12) and at disease progression (n=5) were 2137(767-12100)pg/ml, 1629(785-3430)pg/ml and 4064(1108-7308)pg/ml. The plasma HGF level showed a trend of decreasing during clinical response to crizotinib and elevation upon disease progression, albeit not reaching statistical significance in this small study cohort (p&gt;0.05).

Conclusions. MET expression is commonly seen in NSCLC, and no significant difference were observed between fusion ALK(+) and ALK(-) NSCLC. The baseline plasma HGF concentration varied significantly among ALK(+) NSCLC patients, but showed a trend correlating with therapeutic response and resistant progression, to crizotinib therapy. Prospective study with larger cohorts is warranted to further evaluate the role of MET/HGF as biomarker in ALK targeted therapy.

Citation Format: Yan Feng, Eugen Minca, Wei Zhang, Lihong Yin, Nathan Pennell, Carol Farver, Raymond Tubbs, Angen Liu, Patrick Ma. Tumoral MET expression and plasma HGF level in patients with ALK 2p23 fusion driven lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2374. doi:10.1158/1538-7445.AM2013-2374