Histopathological bronchial reconstruction of human bronchiolitis obliterans

Constrictive bronchiolitis obliterans with a presumptive etiology of preceding feline herpesvirus infection in a cat

Background

Bronchiolar disorders are rarely recognized in cats. Constrictive bronchiolitis obliterans is characterized by concentric peribronchiolar fibrosis and inflammation of the bronchioles, but the underlying causes remain poorly understood in current small animal medicine.

Case presentation

A 9-year-old cat presented with paroxysmal tachypnea, infrequent cough and persistent labor breathing. Thoracic radiography showed lung hyperinflation and bronchointerstitial pattern, and pulmonary function assessment revealed flow limitation in the late-expiratory phase and poor response to short-acting bronchodilator. Dorsally distributed subpleural ground glass opacities with distinct margin and tree-in-bud opacities were observed on lung high-resolution computed tomography. The cat underwent bronchoalveolar lavage (BAL) and showed severe neutrophilic inflammation. Feline herpesvirus was the only pathogen detected in the BAL fluid. Multiple therapeutic attempts were unsuccessful and the cat died 8 weeks after the initial presentation. Necropsy revealed the infiltration of inflammatory cells, obstruction of the bronchiolar lumen, and submucosal concentric fibrosis suggesting constrictive bronchiolitis obliterans. Combining the pre- and post-mortem findings, as well as the time from symptom onset or BAL to necropsy, constrictive bronchiolitis obliterans was possibly triggered by a preceding feline herpesvirus infection in this case.

Conclusions

The history of nonvaccinated status, lower airway neutrophilic inflammation, and presence of feline herpesvirus in the BAL fluid without coexistence of other pathogens led to the presumption that constrictive bronchiolitis obliterans was induced by a preceding feline herpesvirus infection in this cat. The pathological changes of bronchiolitis obliterans induced by a preceding feline herpesvirus infection could be different from that of cats with acute herpesvirus pneumonia, such as intranuclear inclusions would disappear over time and were no longer found 7–10 days after inoculation. The presence of patchy distribution of subpleural ground glass opacities on lung high-resolution computed tomography should raise the suspicion of peribronchiolar fibrosis. Clinical awareness of bronchiolar disorders as a differential diagnosis is important in cats with lung hyperinflation and labored breathing who show poor reversibility to bronchodilator.

Clinical and pathological features of bronchiolitis obliterans requiring lung transplantation in paraneoplastic pemphigus associated with Castleman disease

Summary at a glance

Bronchiolitis obliterans in paraneoplastic pemphigus associated with Castleman disease possesses the progressive nature even when it is treated with intensive medical therapy. Antibodies were at least in low titers before the Lung transplant and remain negative after the procedure. Explanted lungs showed coexistence of cellular destructive bronchiolitis and constrictive bronchiolitis.

Background

Bronchiolitis obliterans (BO) in paraneoplastic pemphigus (PNP) associated with Castleman disease (CD) possesses the progressive nature of pulmonary disease even when it is treated with intensive medical therapy. Lung transplantation (LT) offers an acceptable form of treatment.

Methods

We conducted a retrospective study of two cases of BO in PNP associated with CD who underwent LT between March 2017 and March 2020 at the China‐Japan Friendship Hospital. We also included one case from the literature.

Results

In this patient series, PNP was the primary clinical presentation in all patients, and it was accompanied by respiratory symptoms before/after CD excision. In spite of being treated with various combinations of immunosuppressive and anti‐inflammatory agents, the patients had great or total improvement in mucosal erosions, whereas their pulmonary function test (PFT) deteriorated gradually or sharply. The duration times from disease onset to timing of LT were 1, 2 and 5 years. All antibodies were negative or were present at low titers before the LT procedure and remain negative after the procedure. The histopathological features of explanted lungs showed cellular and coexistent destructive bronchiolitis and constrictive bronchiolitis in two cases. Granulation with numerous foamy macrophages, scattered giant cells and cholesterol clefts were especially prominent in case one.

Conclusion

BO in PNP associated with CD had poor clinical outcomes. LT was preferable choice in end‐stage BO when PNP and CD were controlled.

Intractable diffuse pulmonary diseases: Manual for diagnosis and treatment

This manual has been compiled by a joint production committee with the Diffuse Lung Disease Assembly of the Japanese Respiratory Society (JRS) to provide a practical manual for the epidemiology, diagnosis, and treatment of intractable diffuse pulmonary diseases. The contents are based upon the results of research into these diseases by the Diffuse Pulmonary Diseases Study Group (principal researcher: Sakae Homma) supported by the FY2014-FY2016 Health and Labor Sciences Research Grant on Intractable Diseases. This manual focuses on: 1) pulmonary alveolar microlithiasis, 2) bronchiolitis obliterans, and 3) Hermansky-Pudlak Syndrome with interstitial pneumonia. As these are rare/intractable diffuse lung diseases (2 and 3 were first recognized as specified intractable diseases in 2015), there have not been sufficient epidemiological studies made, and there has been little progress in formulating diagnostic criteria and severity scales; however, the results of Japan's first surveys and research into such details are presented herein. In addition, the manual provides treatment guidance and actual cases for each disease, aiming to assist in the establishment of future modalities. The manual was produced with the goal of enabling clinicians specialized in respiratory apparatus to handle these diseases in clinical settings and of further advancing future research and treatment.

Quantitative computed tomography assessment of bronchiolitis obliterans syndrome after lung transplantation

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a clinical manifestation of chronic allograft rejection following lung transplantation. We examined the quantitative measurements of the proximal airway and vessels and pathologic correlations in subjects with BOS.

METHODS

Patients who received a lung transplant at the Brigham and Women's Hospital between December 1, 2002 and December 31, 2010 were included in this study. We characterized the quantitative CT measures of proximal airways and vessels and pathological changes.

RESULTS

Ninety-four (46.1%) of the 204 subjects were included in the study. There was a significant increase in the airway vessel ratio in subjects who developed progressive BOS compared to controls and non-progressors. There was a significant increase in airway lumen area and decrease in vessel cross-sectional area in patients with BOS compared to controls. Patients with BOS had a significant increase in proximal airway fibrosis compared to controls.

CONCLUSIONS

BOS is characterized by central airway dilation and vascular remodeling, the degree of which is correlated to decrements in lung function. Our data suggest that progressive BOS is a pathologic process that affects both the central and distal airways.

Bronchiolitis obliterans associated with Stevens-Johnson Syndrome: histopathological bronchial reconstruction of the whole lung and immunohistochemical study

This study presents an extremely rare case of constrictive bronchiolitis obliterans (BO) associated with Stevens-Johnson Syndrome (SJS) provides the morphological and immunohistochemical features using histopathological bronchial reconstruction technique. A 27-year-old female developed progressive dyspnea after SJS induced by taking amoxicillin at the age of 10. Finally, she died of exacerbation of type II respiratory failure after 17 years from clinically diagnosed as having BO. Macroscopic bronchial reconstruction of the whole lungs at autopsy showed the beginning of bronchial obliterations was in the 4th to 5th branches, numbering from each segmental bronchus. Once they were obliterated, the distal and proximal bronchi were dilated. Microscopic bronchial reconstruction demonstrated the localization of obliteration was mainly from small bronchi to membranous bronchioli with intermittent airway luminal narrowing or obliteration. Moreover, CD3-, CD20-, and CD68-positive cells were found in the BO lesions. CD34- and D2-40-positive cells were mainly distributed in the peribronchiolar lesions and bronchiolar lumens, respectively. SMA- and TGF-β-positive cells were seen in the fibrous tissue of BO lesions.

[The small airways: normal histology and the main histopathological lesions]

Lesions of the small airway are observed in a wide variety of pulmonary conditions, most of which are due to infection, tobacco and connective tissue diseases. They are sometimes isolated or, more often, associated with involvement of other pulmonary structures such as the bronchi, the lung parenchyma and the pleura. The pathological spectrum of the bronchiolar response to injury is relatively limited. Thus, the same lesion is observed in various clinical settings. There is no correlation between the severity of the small airway involvement seen by the pathologist and the clinical and functional manifestations of bronchiolitis. The causes of bronchiolitis may be classified on a clinical basis, on aetiology or on histological appearance, yet no single classification appears to be suitable. An integrated clinical, radiological, functional and histological approach is needed. As they are seen by the pathologist microscopically, small airway lesions may be subdivided into three categories: (1) simple nonspecific lesions (bronchiolitis - cellular, follicular, granulomatous, obliterative, constrictive) that are never exclusively related to one clinical picture, (2) or displaying a more specific pattern like the respiratory bronchiolitis of the smoker or the histolgical changes of asthma, (3) bronchiolar lesions in conditions described as "interstitial", predominantly centrilobular, involving the small airways and the lung parenchyma, and visible radiologically. After recalling the normal histological appearances of the bronchioles, this review describes the diversity of the histopathological lesions of the small airways.

Airway dilation in bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation

RATIONALE

Bronchiolitis obliterans syndrome (BOS) is a late, non-infectious pulmonary complication following hematopoietic stem cell transplantation (HSCT). There is minimal data published on quantitative radiologic characterization of airway remodeling in these subjects.

OBJECTIVES

To examine quantitative measurements of airway morphology and their correlation with lung function in a cohort of patients who underwent HSCT and developed BOS.

METHODS

All adult patients who underwent allogeneic HSCT at the Dana-Farber Cancer Institute/Brigham and Women's Hospital (n = 1854) between January 1st 2000 and June 30th 2010 were screened for the development of BOS. Clinically acquired high resolution CT (HRCT) scans of the chest were collected. For each subjects discrete measures of airway wall area were performed and the square root of wall area of a 10-mm luminal perimeter (Pi10) was calculated.

MEASUREMENTS AND MAIN RESULTS

We identified 88 cases of BOS, and 37 of these patients had available HRCT. On CT scans obtained after BOS diagnosis, the Pi10 decreased (consistent with airway dilation) as compared with pre-BOS values (p < 0.001). After HSCT the Pi10 correlated with FEV(1)% predicted (r = 0.636, p < 0.0001), and RV/TLC% predicted (r = -0.736, p < 0.0001), even after adjusting for age, sex and total lung capacity (p < 0.0001 for both).

CONCLUSIONS

On HRCT scan BOS is characterized by central airway dilation, the degree of which is correlated to decrements in lung function. This is opposite of what has been previously demonstrated in COPD and asthma that quantitative measure of proximal airway wall thickening directly correlate with pulmonary function. Our data suggests that the pathologic process affecting the central airways is different from the pathology observed in the distal airways. Further work is needed to determine if such change can be used as a sensitive and specific tool for the future diagnosis and staging of BOS.

Early pathologic findings of bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation: a proposal from a case

Bronchiolitis obliterans (BO) is one of the serious, noninfectious pulmonary complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Early diagnosis of BO is usually difficult because patients are often asymptomatic at an initial stage of the disease and pathologic findings are available mostly at the late stages. Therefore, the diagnosis of the disease is based on the pulmonary function test using the National Institute of Health consensus criteria. Here, we report a case of slowly progressive BO. A biopsy specimen at an early stage demonstrated alveolar destruction with lymphocyte infiltration in bronchial walls and mild narrowing of bronchioles without fibrosis, those were strongly indicative of initial pathologic changes of BO. Definitive BO followed, which was proven by both clinical course and autopsy. While alloreactive lymphocytes associated with chronic graft-versus-host disease are believed to initiate BO, we present a rare case that directly implies such a scenario.