Granulomatous Lung Diseases: A Practical Approach and Review of Common Entities

Granulomas are frequently encountered by pathologists in all types of lung specimens and arise from diverse etiologies. They should always be reported as necrotizing or non-necrotizing, with microorganism stains performed to evaluate for infection. With attention to distribution, quality (poorly vs well-formed), associated features, and correlation with clinical, radiologic, and laboratory data, the differential diagnosis for granulomatous lung disease can usually be narrowed to a clinically helpful "short list." This review describes a practical approach to pulmonary granulomas and reviews the clinicopathological aspects of common entities, including infectious (mycobacteria, fungi) and noninfectious (hypersensitivity pneumonitis, sarcoid, and vasculitis) causes.

MMP14high macrophages orchestrate progressive pulmonary fibrosis in SR-Ag-induced hypersensitivity pneumonitis

Fibrotic hypersensitivity pneumonitis (FHP) is a fatal interstitial pulmonary disease with limited treatment options. Lung macrophages are a heterogeneous cell population that exhibit distinct subsets with divergent functions, playing pivotal roles in the progression of pulmonary fibrosis. However, the specific macrophage subpopulations and underlying mechanisms involved in the disease remain largely unexplored. In this study, a decision tree model showed that matrix metalloproteinase-14 (MMP14) had higher scores for important features in the up-regulated genes in macrophages from mice exposed to the Saccharopolyspora rectivirgula antigen (SR-Ag). Using single-cell RNA sequencing (scRNA-seq) analysis of hypersensitivity pneumonitis (HP) mice profiles, we identified MMP14high macrophage subcluster with a predominant M2 phenotype that exhibited higher activity in promoting fibroblast-to myofibroblast transition (FMT). We demonstrated that suppressing toll-like receptor 2 (TLR2) and nuclear factor kappa-B (NF-κB) could attenuate MMP14 expression and exosome secretion in macrophages stimulation with SR-Ag. The exosomes derived from MMP14-overexpressing macrophages were found to be more effective in regulating the transition of fibroblasts through exosomal MMP14. Importantly, it was observed that the transfer of MMP14-overexpressing macrophages into mice promoted lung inflammation and fibrosis induced by SR-Ag. NSC-405020 binding to the hemopexin domain (PEX) of MMP-14 ameliorated lung inflammation and fibrosis induced by SR-Ag in mice. Thus, MMP14-overexpressing macrophages may be an important mechanism contributing to the exacerbation of allergic reactions. Our results indicated that MMP14 in macrophages has the potential to be a therapeutic target for HP.

Bird ownership and pulmonary outcomes apart from hypersensitivity pneumonitis in European older adults

BACKGROUND

Exposure to birds has been linked with several lung pathologies and especially hypersensitivity pneumonitis, but discordant literature exist on the potential effects of this exposure on other respiratory pathologies.

AIM

This study aims to examine the associations between bird ownership and asthma, lung cancer, and chronic obstructive pulmonary disease (COPD) in older European adults.

METHODS

A total of 28,109 participants from the Survey of Health, Ageing, and Retirement in Europe were employed and analyzed with multivariate logistic regressions.

RESULTS

No association was found with asthma or lung cancer. Bird ownership increased the odds for COPD diagnosis (OR=1.30; 95 % CI: 1.12-1.51) and more so in males (OR=1.53; 95 % CI: 1.25-1.87) after adjustment for demographic, respiratory, lifestyle, and socioeconomic factors. Male bird owners who smoke had an even more increased risk compared to non-smokers, as did those who lived in multi-person households compared to those living alone.

CONCLUSION

Bird ownership may be positively associated with COPD in older European males.

Impact of antigen identification on transplant free survival in interstitial lung disease

INTRODUCTION

Antigen identification impacts diagnosis as well as prognosis in patients with hypersensitivity pneumonitis. An antigen may also be present in other etiologies of interstitial lung disease, however it is unknown whether identification impacts survival.

METHODS

We evaluated a retrospective cohort in order to determine if antigen identification affects transplant free survival in patients with hypersensitivity pneumonitis, idiopathic pulmonary fibrosis, connective tissue disease interstitial lung disease, and interstitial pneumonia with autoimmune features. Only patients with definite or high probability of hypersensitivity pneumonitis by American Thoracic Society guidelines were included in the analysis.

RESULTS

Transplant free survival was improved with antigen identification in patients with hypersensitivity pneumonitis but not in patients with idiopathic pulmonary fibrosis, connective tissue disease interstitial lung disease, and interstitial pneumonia with autoimmune features.

CONCLUSION

Our study suggests that removal of identified antigen in interstitial lung diseases other than hypersensitivity pneumonitis may not be impactful. Additionally, it further suggests that definitive diagnosis of hypersensitivity pneumonitis with bronchoalveolar lavage and transbronchial biopsy may be beneficial prior to recommending antigen removal.

Single-Cell Profiling of Cells in the Lung of a Patient with Chronic Hypersensitivity Pneumonitis Reveals Inflammatory Niche with Abundant CD39+ T Cells with Functional ATPase Phenotype: A Case Study

This study investigated immune cell characteristics in chronic hypersensitivity pneumonitis (HP), focusing on CD39-expressing cells' impact on inflammation and tissue remodelling. Lung tissue from an HP patient was analysed using single-cell transcriptomics, flow cytometry, and gene expression profiling. The tissue revealed diverse cell types like macrophages, T cells, fibroblasts, and regulatory T cells (Tregs). CD39-expressing Tregs exhibited heightened ATP hydrolysis capacity and regulatory gene expression. CD39hi cells displayed markers of both Tregs and proinflammatory Th17 cells, suggesting transitional properties. Communication networks involving molecules like SPP1, collagen, CSF1, and IL-1β were identified, hinting at interactions between cell types in HP pathogenesis. This research provides insights into the immune response and cell interactions in chronic HP. CD39-expressing cells dual nature as Tregs and Th17 cells suggests a role in modulating lung inflammation, potentially affecting disease progression. These findings lay the groundwork for further research, underscoring CD39-expressing cells as potential therapeutic targets in HP.

ATS/JRS/ALAT Hypersensitivity Pneumonitis Guidelines for Diagnosis of humidifier lung and summer-type hypersensitivity pneumonitis

BACKGROUND

The ATS/JRS/ALAT Guidelines for the Diagnosis of Hypersensitivity Pneumonitis (GL for HP) were published in 2020. Humidifier lung and summer-type HP are forms of HP, but it is unclear whether they can be diagnosed using GL for HP. This study examined the level of confidence where humidifier lung and summer-type HP can be diagnosed with GL for HP.

METHODS

Data from 23 patients with humidifier lung and 20 patients with summer-type HP (mean age, 67.3 and 57.4 years, respectively) diagnosed between October 2012 and January 2022 were retrospectively reviewed. We evaluated high resolution computed tomography (HRCT) patterns, bronchoalveolar lavage fluid (BALF) findings, exposures, and histopathological findings to determine the level of confidence where a diagnosis of HP could be made using the GL for HP.

RESULTS

HRCT pattern was classified as typical HP in 5 (22%) and compatible with HP in 18 (78%) patients with humidifier lung and considered as typical HP in 17 (85%) and compatible with HP in 3 (15%) patients with summer-type. The confidence level for diagnosis of HP was definite in 2 (8.7%), moderate in 14 (60.9%), and low in 7 (30.4%) patients with humidifier lung. It was definite in 12 (60%), high in 3 (15%), and moderate in 5 (25%) patients with summer-type HP.

CONCLUSIONS

GL for HP showed utility in diagnosing humidifier lung in many patients with a moderate to low confidence. However, there was a definite to high confidence for patients with summer-type HP.

Pathologic Criteria for the Diagnosis of Usual Interstitial Pneumonia vs Fibrotic Hypersensitivity Pneumonitis in Transbronchial Cryobiopsies

Transbronchial cryobiopsy (TBCB) is increasingly used for the diagnosis of fibrosing interstitial pneumonias, but there are few detailed descriptions of the pathologic findings in such cases. It has been proposed that a combination of patchy fibrosis and fibroblast foci with an absence of alternative features is diagnostic of usual interstitial pneumonia (UIP; ie, idiopathic pulmonary fibrosis [IPF]) in TBCB. In this study, we reviewed 121 TBCB in which a diagnosis of fibrotic hypersensitivity pneumonitis (FHP; n = 83) or IPF (n = 38) was made by multidisciplinary discussion and evaluated a range of pathologic features. Patchy fibrosis was found in 65 of 83 (78%) biopsies from FHP and 32of 38 (84%) biopsies from UIP/IPF cases. Fibroblast foci were present in 47 of 83 (57%) FHP and 27 of 38 (71%) UIP/IPF cases. Fibroblast foci/patchy fibrosis combined did not favor either diagnosis. Architectural distortion was seen in 54 of 83 (65%) FHP and 32 of 38 (84%) UIP/IPF cases (odds ratio [OR] for FHP, 0.35; P = .036) and honeycombing in 18 of 83 (22%) and 17 of 38 (45%), respectively (OR, 0.37; P = .014). Airspace giant cells/granulomas were present in 13 of 83 (20%) FHP and 1 of 38 (2.6%) UIP/IPF cases (OR for FHP, 6.87; P = .068), and interstitial giant cells/granulomas in 20 of 83 (24%) FHP and 0 of 38 (0%) UIP/IPF (OR, 6.7 x 106; P = .000). We conclude that patchy fibrosis plus fibroblast foci can be found in TBCB from both FHP and UIP/IPF. The complete absence of architectural distortion/honeycombing favors a diagnosis of FHP, as does the presence of airspace or interstitial giant cells/granulomas, but these measures are insensitive, and many cases of FHP cannot be separated from UIP/IPF on TBCB.

Immunopathological Mechanisms of Bird-Related Hypersensitivity Pneumonitis

Bird-related hypersensitivity pneumonitis (BRHP) is an interstitial lung disease induced by avian proteins. The immunopathological pathways involved in the disease are still unknown. This study assesses the cellular immune response and the cytokine pattern in a mouse model of BRHP. On days -3 and -1, mice were intraperitoneally sensitized with commercial pigeon serum (PS) or saline. Intranasal instillations with PS or saline were carried out on three consecutive days/week over either 3 weeks (Group 1) or 12 weeks (Group 2). Leukocyte and cytokine patterns in lung tissue and pulmonary inflammation in bronchoalveolar lavage (BAL) were analysed. Both groups presented increases in resident monocytes, interstitial macrophages and type 2 dendritic cells (DCs), but also reductions in inflammatory monocytes, alveolar macrophages and tolerogenic DCs compared with their control groups. Group 1 had increased levels of eosinophils and T cells with reductions in neutrophils and B cells, while Group 2 showed high levels of B cells. Both groups exhibited increases in Th1 and Th2 cytokines. Group 2 also showed increased levels of IL-23, a Th17 cytokine. Increased levels of neutrophils, eosinophils and lymphocytes were observed in BAL samples of both groups compared with controls. In the first stages of BRHP, there is a mixed Th1/Th2 immune response, while during the progression of the disease, although there is a Th1 response, the cytokine levels seem to indicate a switch towards a Th2/Th17 mixed response.

Hypersensitivity Pneumonitis: An Updated Diagnostic Guide for Internists

This summary highlights updated definitions, terminology, and classification systems proposed in the diagnosis of hypersensitivity pneumonitis. Clinical presentation, epidemiology, and pathophysiology are reviewed from the most recent data. Radiographic and histopathologic diagnostic criteria are presented in a manner relevant to the practice of general medicine internists, including new guideline recommendations. The role of adjunctive tests, such as serum IgG testing, bronchoalveolar lavage lymphocyte analysis, and pulmonary function testing is discussed in the context of supporting diagnostic confidence for hypersensitivity pneumonitis diagnosis. Finally, new diagnostic algorithms are synthesized and applied to the general internal medicine setting.

Diagnosis of Hypersensitivity Pneumonitis: Review and Summary of American College of Chest Physicians Statement

Assessment of lung biopsies for the diagnosis of hypersensitivity pneumonitis (HP) is one of the most difficult diagnostic problems for surgical pathologists. It is a form of interstitial lung disease resulting from an immune reaction provoked by an inhaled antigen in susceptible individuals. Although this definition sounds simple, in practice, the diagnosis of HP can be challenging. To address these issues, the American College of Chest Physicians (CHEST) has recently published a guideline for the diagnosis of HP. In this review, we will explore the multidisciplinary diagnostic evaluation of HP with a focus on the pathologic features as outlined in the CHEST guidelines. The histologic criteria are divided into 4 diagnostic categories: (1) Typical nonfibrotic HP or fibrotic HP; (2) Compatible with nonfibrotic HP or fibrotic HP; (3) Indeterminate for nonfibrotic or fibrotic HP; and (4) Alternative Diagnosis. It is important to emphasize that patterns 1 to 3 do not represent discrete histologic entities or pathologic diagnoses. Rather, these categories are meant to serve as a practical guide for organizing a complex set of overlapping histologic patterns into an integrated diagnostic framework for facilitating multidisciplinary discussion. High-resolution computed tomography features are also summarized, emphasizing how the correlation of lung biopsies with computed tomography findings can help to favor the diagnosis, particularly in cases where biopsies are not typical for HP. This review highlights details of the histologic spectrum of HP as well as the utility of different types of biopsies and bronchoalveolar lavage. We also emphasize the importance of multidisciplinary discussion and the complex differential diagnosis.

[Comparative pathomorphological characteristics of idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis]

The paper presents an X-ray morphological differential diagnosis of idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (FHP). It describes the etiology, pathogenesis, radiological signs, and pathoanatomy of IPF and FHP. For differential diagnosis, radiological and morphological signs were studied in 105 patients with IPF and in 111 patients with FHP. The mean ages of patients with IPF or FHP were 65.0±8.9 and 48.9±12.3 years, respectively. The history of IPF to the moment of its diagnosis ranged from 1 to 18 months, while that of FHP was 35 to 79 days. The authors describe the additional morphological signs of FHP: delicate collagen fibrosis; smooth muscle metaplasia in the interalveolar septa and fibrotic areas; fibroblastic foci mainly in the walls of bronchioles; plasma cell infiltration of interalveolar septa with a touch of neutrophils and eosinophils. A table has been compiled for differential diagnosis according to the morphological signs of IPF and FHP.

Elevated Serum Amyloid a Levels Are not Specific for Sarcoidosis but Associate with a Fibrotic Pulmonary Phenotype

Elevated Serum Amyloid A (SAA) levels have been found in several inflammatory diseases, including sarcoidosis. SAA is suggested to be involved in sarcoidosis pathogenesis by involvement in granuloma formation and maintenance. We hypothesized that SAA serum levels would be higher in sarcoidosis compared to other non-infectious granulomatous and non-granulomatous diseases. SAA levels were measured in serum from sarcoidosis, Hypersensitivity pneumonitis (HP), and (eosinophilic) granulomatosis with polyangiitis ((E)GPA) patients. Idiopathic pulmonary fibrosis (IPF) patients were included as non-granulomatous disease group. SAA levels of patients with sarcoidosis (31.0 µg/mL), HP (23.4 µg/mL), (E)GPA (36.9 µg/mL), and IPF (22.1 µg/mL) were all higher than SAA levels of healthy controls (10.1 µg/mL). SAA levels did not differ between the diagnostic groups. When SAA serum levels were analyzed in sarcoidosis subgroups, fibrotic sarcoidosis patients showed higher SAA levels than sarcoidosis patients without fibrosis (47.8 µg/mL vs. 29.4 µg/mL, p = 0.005). To conclude, the observation that fibrotic sarcoidosis patients have higher SAA levels, together with our finding that SAA levels were also increased in IPF patients, suggests that SAA may next to granulomatous processes also reflect the process of fibrogenesis. Further studies should clarify the exact role of SAA in fibrosis and the underlying mechanisms involved.

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

The Transcription Factor SCX is a Potential Serum Biomarker of Fibrotic Diseases

Fibrosing diseases are causes of morbidity and mortality around the world, and they are characterized by excessive extracellular matrix (ECM) accumulation. The bHLH transcription factor scleraxis (SCX) regulates the synthesis of ECM proteins in heart fibrosis. SCX expression was evaluated in lung fibroblasts and tissue derived from fibrotic disease patients and healthy controls. We also measured SCX in sera from 57 healthy controls, and 56 Idiopathic Pulmonary Fibrosis (IPF), 40 Hypersensitivity Pneumonitis (HP), and 100 Systemic Sclerosis (SSc) patients. We report high SCX expression in fibroblasts and tissue from IPF patients versus controls. High SCX-serum levels were observed in IPF (0.663 ± 0.559 ng/mL, p < 0.01) and SSc (0.611 ± 0.296 ng/mL, p < 0.001), versus controls (0.351 ± 0.207 ng/mL) and HP (0.323 ± 0.323 ng/mL). Serum levels of the SCX heterodimerization partner, TCF3, did not associate with fibrotic illness. IPF patients with severely affected respiratory capacities and late-stage SSc patients presenting anti-topoisomerase I antibodies and interstitial lung disease showed the highest SCX-serum levels. SCX gain-of-function induced the expression of alpha-smooth muscle actin (α-SMA/ACTA2) in fibroblasts when co-overexpressed with TCF3. As late and severe stages of the fibrotic processes correlated with high circulating SCX, we postulate it as a candidate biomarker of fibrosis and a potential therapeutic target.

Histology is critical but not always for the diagnosis of chronic hypersensitivity pneumonitis

BACKGROUND

The diagnosis of chronic hypersensitivity pneumonitis (CHP) is often based on the pathology, but evidence is scarce that a pathological diagnosis of CHP may mislead the multidisciplinary diagnosis.

METHOD

We enrolled patients from the consultation case archive whose pathological findings were suggestive of CHP but had a multidisciplinary diagnosis of non-CHP. The histopathological slides were sent to another pathologist, and the ones confirmed with CHP were sent for an additional multidisciplinary discussion (MDD). We examined clinicopathological features of the cases confirmed to be non-CHP through MDD.

RESULTS

Among the 243 cases, five were diagnosed as non-CHP through an additional MDD. The most common causes of discrepancy were the presence of strong autoimmune features, a low lymphocyte level in the bronchoalveolar lavage fluid, and a lack of nodular shadow or mosaic attenuation on computed tomography.

CONCLUSIONS

Cases of suspected CHP on pathology may be determined to be non-CHP through MDD.

Pantoea agglomerans chronic exposure induces epithelial-mesenchymal transition in human lung epithelial cells and mice lungs

Pantoea agglomerans is gram-negative bacteria widely distributed in nature. It predominates in inhalable dust from grain, herbs, and flax, and was identified as the most important cause of hypersensitivity pneumonitis (HP) in eastern Poland. To better understand the molecular mechanism of HP development studies focused on the interactions between P. agglomerans and alveolar epithelial cells as well as lung tissue with particular emphasis on the epithelial-mesenchymal transition (EMT). The studies were conducted on human normal lung epithelial NL20 cells and mice strain C57BL/6J. Cells and mice underwent chronic exposure to saline extract of P. agglomerans (SE-PA). Morphological changes were evaluated under light microscopy, the concentration of fibrosis markers was examined by the ELISA method, while the expression of genes involved in EMT was evaluated by RealTime PCR. During incubation with SE-PA epithelial cells underwent conversion and assumed fibroblast phenotype characterized by a decrease in epithelial cells markers (CDH1, CLDN1, JUP) and increase in mesenchymal cells markers (FN1, VIM, CDH2). Mice lungs collected after 14 days of SE-PA treatment revealed inflammation with marked lymphocytes infiltration. The intensified inflammatory process accompanied by increased proliferation of fibrous connective tissue was noted in mice lungs after 28 days of SE-PA exposure. Histological changes correlated with an increase of fibrosis markers (hydroxyproline, collagens), downregulation of epithelial markers (Cdh1, Cldn1, Jup, Ocln) and upregulation of myofibroblasts markers (Acta2, Cdh2, Fn1, Vim). Obtained results revealed SE-PA ability to induce EMT in human lung epithelial cells and mice lung tissue, with the scale of changes proportional to the time of treatment.

A rare association of cutaneous leukocytoclastic angiitis (hypersensitivity vasculitis) and hypersensitivity pneumonia (extrinsic allergic alveolitis) in a pigeon breeder - case report and literature review

Extrinsic allergic alveolitis is an occupational condition intensively studied and published about, unlike cutaneous leukocytoclastic angiitis. The coexistence of these two diseases is even more rare in the same patient with exposure to occupational pollutants of animal origin. We present the case of a 44-year-old man, a pigeon breeder admitted to hospital with a pruritic purpuric eruption and lower limb paresthesia, dyspnea on exertion, polymyalgia rheumatica, mixed polyarthralgias. Based on the clinical, paraclinical and laboratory investigations (electroneuromyography, plethysmography, computed tomography scan, musculocutaneous biopsy, current laboratory tests and immunoassays), the main diagnoses of extrinsic allergic alveolitis and leukocytoclastic vasculitis were determined. The patient underwent treatment with corticosteroids with a favorable outcome, but which becomes aggravated by the occurrence of necrotic skin lesions at the cessation of corticosteroid therapy on the patient's own initiative. After the resumption of the corticosteroid therapy, the lesions and symptoms improve. To our knowledge, this case report is the first one that describes an association of two major conditions, extrinsic allergic alveolitis and cutaneous leukocytoclastic angiitis, in the same clinical context of an occupational exposure to specific pollutants. Long-term corticosteroid therapy has proved to be useful in preventing relapses and improving the patient's clinical status with the association of cutaneous leukocytoclastic angiitis and extrinsic allergic alveolitis. Considering our findings in this case report, we may suggest the inclusion of systemic vasculitis on the list of recognized professional diseases.

Marijuana medusa: The many pulmonary faces of marijuana inhalation in adolescent males

Marijuana use has risen dramatically over the past decade. Over this same time period, pediatric hospitals have seen an increase in presentation of adolescents with acute respiratory symptoms after recent marijuana inhalation. We report a case series of three adolescent males with significant findings of bilateral pulmonary nodules and ground glass opacities on chest imaging associated with recent marijuana inhalation. Lung biopsies in two of the three patients confirmed silica-induced pneumoconiosis. The third patient was diagnosed with acute hypersensitivity pneumonitis without lung biopsy. Improvement in clinical symptoms and lung function testing were noted in two of three patients after marijuana inhalation cessation. This case series highlights the variety of severe pulmonary presentations in adolescents following recent marijuana inhalation. Future studies are required to assess whether these presenting pulmonary complications are from direct marijuana exposure or indirect associations with marijuana inhalation injuries.

Dendritic Cell Trafficking and Function in Rare Lung Diseases

Dendritic cells (DCs) are highly specialized immune cells that capture antigens and then migrate to lymphoid tissue and present antigen to T cells. This critical function of DCs is well defined, and recent studies further demonstrate that DCs are also key regulators of several innate immune responses. Studies focused on the roles of DCs in the pathogenesis of common lung diseases, such as asthma, infection, and cancer, have traditionally driven our mechanistic understanding of pulmonary DC biology. The emerging development of novel DC reagents, techniques, and genetically modified animal models has provided abundant data revealing distinct populations of DCs in the lung, and allow us to examine mechanisms of DC development, migration, and function in pulmonary disease with unprecedented detail. This enhanced understanding of DCs permits the examination of the potential role of DCs in diseases with known or suspected immunological underpinnings. Recent advances in the study of rare lung diseases, including pulmonary Langerhans cell histiocytosis, sarcoidosis, hypersensitivity pneumonitis, and pulmonary fibrosis, reveal expanding potential pathogenic roles for DCs. Here, we provide a review of DC development, trafficking, and effector functions in the lung, and discuss how alterations in these DC pathways contribute to the pathogenesis of rare lung diseases.

Spectrum of interstitial lung disease from a tertiary care hospital in Karachi

OBJECTIVE

To determine the clinical features and patterns of interstitial lung disease.

METHODS

This retrospective study was conducted at the Aga Khan University Hospital, Karachi, and comprised record of patients diagnosed with interstitial lung disease from January 2005 to December 2015. All patients aged 16 years and above diagnosed with interstitial lung disease on the basis of clinical features, radiological features on high-resolution computed tomography of the chest, and lung biopsies were included. SPSS 19 was used for data analysis.

RESULTS

Of the 537 patients, 324(60.3%) of the participants were females. The overall mean age was 60.5±14.9 years. The most common co-morbid condition was diabetes mellitus in 72(13.4%) patients, followed by hypertension in 48(8.9%) and ischaemic heart disease in 21(3.9%). The most common interstitial lung disease was idiopathic pulmonary fibrosis in 217(40.4%) patients, followed by non-specific interstitial pneumonia in 106(19.7%), sarcoidosis in 82(15.3%) and connective tissue disease-related interstitial lung disease in 56(10.4%) patients.

CONCLUSIONS

Idiopathic pulmonary fibrosis was found to be the most common interstitial lung disease subtype followed by non-specific interstitial pneumonia, sarcoidosis and connective tissue disease-related-interstitial lung disease.

Hypersensitivity pneumonitis onset and severity is regulated by CD103 dendritic cell expression

Background

Pulmonary dendritic cells drive lung responses to foreign antigens, including Saccharopolyspora rectivirgula, a causative agent of hypersensitivity pneumonitis. While the airway inflammatory mechanisms involved in hypersensitivity pneumonitis are well described, the mechanisms leading to the break in homeostasis and hypersensitivity pneumonitis onset are not well-described, and could involve CD103⁺ dendritic cells, which are found at baseline and during inflammatory responses in the lung. However, recent demonstration of the ability of CD103⁺ dendritic cells to induce inflammatory responses starkly contrasts with their classically described role as regulatory cells. These discrepancies may be attributable to the lack of current information on the importance of CD103 expression and modulation on these cells during inflammatory episodes.

Methods

To verify the importance of CD103 expression in the regulation of hypersensitivity pneumonitis, wild-type and Cd103^-/- mice were exposed intranasally to S. rectivirgula and airway inflammation was quantified. Surface expression of CD103 in response to S. rectivirgula exposure was studied and cell transfers were used to determine the relative importance of CD103 expression on dendritic cells and T cells in regulating the inflammation in hypersensitivity pneumonitis.

Results

Cd103^-/- mice developed an exacerbated inflammatory response as early as 18h following S. rectivirgula exposure. CD103 expression on dendritic cells was downregulated quickly following S. rectivirgula exposure, and cell transfers demonstrated that CD103 expression on dendritic cells specifically (and not T cells) regulates the onset and severity of this response.

Conclusion

All in all, we demonstrate that CD103 expression by dendritic cells, but not T cells, is crucial for homeostasis maintenance and the regulation of the T_H17 airway inflammatory response in hypersensitivity pneumonitis.

[Idiopathic interstitial pneumonias in 2016]

Idiopathic interstitial pneumonias comprise 8 clinicopathological entities, most of them with a chronic course and various prognosis. Idiopathic pulmonary fibrosis is the most frequent and most severe of these. Computed tomography has an important role for its diagnosis. It can identify the corresponding pathological pattern of usual interstitial pneumonia in about 50 percent of cases. It can suggest differential diagnosis in other cases, most frequently fibrosing nonspecific interstitial pneumonia and chronic hypersensitivity pneumonitis. Imaging features should be integrated to clinical and available pathologic data during multidisciplinary team meetings involving physicians with a good knowledge of interstitial diseases. Some cases may be unclassifiable, but these could later be reclassified as new data may occur or imaging features may change. Surgical lung biopsy is being less frequently performed and an emerging less invasive technique, lung cryobiopsy, is under evaluation. Pleuroparenchymal fibroelastosis is a distinct entity only recently described, with uncertain prevalence and prognosis that seems being quite often associated to another pattern of interstitial pneumonia.

[Hypersensitivity pneumonitis. A series of nine cases with surgical lung biopsy]

In a series of nine patients with histopathological diagnosis of hypersensitivity pneumonitis, we retrospectively evaluated clinical data, exposure related factors, pulmonary function tests and chest computed tomography scans. A restrictive abnormality with reduction of diffusion capacity for carbon monoxide was mainly found. Chest scans showed fibrotic patterns in most cases; ground glass attenuation areas with mosaic pattern and consolidation in the rest. Exposure to avian antigens, cereal grains and air conditioners contaminated with fungi yeasts and bacteria, were suspected from clinical data in two-thirds of the cases. Since there are no unique features that allow differentiation from other interstitial lung diseases, a high clinical suspicion is required and a careful search of environmental exposure to possible antigens is needed that, together with clinical, radiological and pathological data, may lead to diagnosis.

Fatal hypersensitivity pneumonitis after chemical occupational exposure

Hypersensitivity pneumonitis (HP; extrinsic allergic alveolitis) is a rare non-immunoglobulin E (IgE)-mediated inflammatory lung disease caused by inhalation exposure (occupational, recreational or ordinary home exposure). A 36-year-old female patient, without significant medical history, is referred to an outpatient pulmonology clinic for dry cough, shortness of breath, fever, fatigue and weight loss. Chest high-resolution computed tomography (HRCT) was performed, and significant lung fibrosis (especially centrilobular and interlobular in bilateral "thick lines"), traction bronchiectasis and alveolitis in both superior lobes are described. Lung function tests showed severe restrictive dysfunction. Transfer factor of the lung for carbon monoxide (TLCO) being very low, the flexible bronchoscopy was contraindicated. Surgical lung biopsy was performed. Histopathological examination showed characteristic lesions of chronic bilateral hypersensitivity pneumonitis. The patient died four days after the surgical intervention due to post-operative complications. Exposure to various chemical substances can form bonds with human proteins molecules and induce an exaggerated immune response in susceptible individuals. A high index of suspicion of occupational exposure can determine an early diagnosis with a better outcome.

Environmental, Inhaled and Ingested Causes of Pulmonary Fibrosis

Pulmonary fibrosis is a general term that refers to a collection of connective tissue around alveolar structures. There are over 200 disorders where the lungs may be involved in a fibrotic response. To determine the cause of pulmonary fibrosis requires an in depth understanding of the pathogenesis of pulmonary fibrosis and breadth of knowledge of the causative agents and associated disorders that may lead to pulmonary fibrosis. A comprehensive evaluation of the patient is absolutely essential, starting with detailed history that includes an occupational and environmental history because fibrogenic exposures can occur in many settings. Equally important is a history of ingestion of pharmaceutical or nonpharmaceutical substances. A physical examination and judicious investigations are always a part of any comprehensive clinical assessment but they are not commonly helpful in elucidating the cause of most pulmonary fibrotic disorders. Although, a chest film is invariably done, a logical and strongly recommended next step is a high-resolution computed tomography (HRCT). HRCT provides a better assessment of the radiological pattern, may suggest a diagnosis as well as direct the site, and type of lung biopsy. If the history and investigations do not lead to a diagnosis then a lung biopsy is required. Prevention or removal of the inciting agent is critical to the treatment of these disorders and in some instances corticosteroids may be of help.

A commentary on interstitial pneumonitis induced by docetaxel: clinical cases and systematic review of the literature

BACKGROUND

Pulmonary toxicity is a well-known complication observed with several anticancer drugs. Docetaxel, a taxane chemotherapy drug widely used in the treatment of many types of solid tumors including non-small cell lung cancer (NSCLC), rarely causes infiltrative pneumonitis. The exact mechanism by which docetaxel develops this side effect is not well understood; probably it is produced by type I and IV hypersensitivity responses. Here we describe 2 cases of infiltrative pneumonitis induced by docetaxel as second-line chemotherapy in advanced NSCLC.

MATERIALS AND METHODS

Two patients with advanced NSCLC were treated with weekly docetaxel as second-line chemotherapy. After 3 courses of chemotherapy, restaging computed tomography (CT) of the chest revealed bilateral diffuse ground-glass opacities with a peribronchial distribution possibly indicative of hypersensitivity pneumonitis. No evidence of pulmonary embolus or pleural effusion was found. Fiberoptic bronchoscopy showed normal bronchi without lymphangitis; biopsies showed interstitial fibrosis without tumor cells. Bronchial tissue laboratory tests for fungi or bacilli were negative. No malignant cells were found at bronchoalveolar lavage. The patients were given high-dose corticosteroid therapy with prednisone 0.7 mg per kilogram per day.

RESULTS

After 1 month of therapy, contrast-enhanced chest CT showed complete disappearance of the pulmonary changes in both patients. Spirometry and blood gas analysis revealed complete recovery of pulmonary function. The patients continued their oncological follow-up program.

CONCLUSIONS

Pulmonary injury is a rare adverse event during docetaxel chemotherapy. Prompt treatment with high-dose corticosteroids is needed to avoid worsening of respiratory performance.

Granulomas and giant cells in hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is an immunologically mediated form of diffuse lung disease, with histopathologic features that include cellular bronchiolitis, interstitial pneumonia, poorly formed granulomas, isolated multinucleated giant cells (MNGCs), organizing pneumonia, and interstitial fibrosis. This study describes the clinical and histopathologic findings in a retrospective series of 40 consecutive patients diagnosed with HP at the Mayo Clinic in Rochester, MN, between 1997 and 2011. Because the literature indicates that granulomas and MNGCs are located in the interstitium, particular attention was given to their distribution. Of the 40 patients, 33 underwent surgical lung biopsy and 7 underwent lung transplantation. Thirty-eight (95%) patients had interstitial pneumonia; 37 (93%), cellular bronchiolitis; 32 (80%), nonnecrotizing granulomas; 31 (78%), isolated MNGCs; 34 (85%) organizing pneumonia, and 31 (78%); interstitial fibrosis. In 27 cases, the granulomas were within airspaces; and in 26, they were interstitial. In 25 cases, MNGCs were within airspaces; and in 24, they were interstitial. In 3 (8%) cases, both granulomas and MNGCs were seen only within airspaces. Interstitial fibrosis was centrilobular in 22 cases, resembled usual interstitial pneumonia in 18 cases, and resembled nonspecific interstitial pneumonia in 11 cases. The "classic triad" of bronchiolitis, interstitial pneumonia, and granulomas was seen in 29 (73%) cases and was most frequent in biopsy than explant specimens (P = .004). This study confirms that granulomas and MNGCs are not confined to the pulmonary interstitium in HP.

Hypersensitivity Pneumonitis: A Comprehensive Review

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a complex pulmonary syndrome mediated by the immune system and caused by inhalation of a wide variety of antigens to which the individual has been previously sensitized. The pathobiology of the disease is not fully understood, but in addition to the triggers that initiate the disease, host/genetic factors are likely to be important, as only a minority of exposed individuals develop HP. Due to the lack of a diagnostic gold standard, the diagnosis of HP is not straightforward and relies on the integration of a number of factors, including history of exposure, precipitating antibodies to the offending antigen, clinical features, bronchoalveolar lavage, and radiological and pathologic features. However, in the appropriate setting, a high index of suspicion is critically important and may obviate the need for more invasive tests. Clinical presentation and natural history vary widely. Acute forms generally resolve without sequelae, while chronic forms, which are caused by persistent low-grade exposures, are associated with poor prognosis. Corticosteroids may be useful in acute episodes for symptomatic relief or in chronic and progressive disease, but their long-term efficacy has never been validated in prospective clinical trials. Ideally, patients with HP should be referred to centers with expertise, as the overlap with other forms of interstitial lung disease may be substantial. Making the correct diagnosis has critical therapeutic and prognostic implications.

Cytological analysis of bronchoalveolar lavage in patients with interstitial lung diseases and the relation of cytological analysis to fibrosis in high-resolution computed tomography

OBJECTIVE

To evaluate the value of differential cytology of bronchoalveolar lavage (BAL) in common interstitial lung diseases (ILDs) and its relation with high-resolution computed tomography (HRCT) fibrosis.

STUDY DESIGN

A retrospective analysis of BAL from 91 patients. The total and percentage of cells were collected and analyzed according to published guidelines.

RESULTS

The main diagnoses were connective tissue diseases (n = 24), hypersensitivity pneumonitis (HP) (n = 15), sarcoidosis (n = 12), idiopathic pulmonary fibrosis (IPF) (n = 14), smoking-related interstitial lung diseases (sr-ILDs) (n = 8), aspiration (n = 8), and others (n = 10). The lymphocyte percentages differed among diagnoses (F = 2.85, p = 0.008). A greater number of lymphocytes were found in sarcoidosis (Md = 20%, IQR = 12-45%), HP (Md = 29%, IQR = 13-55%), and organizing pneumonia (Md = 28, IQR = 9-50%). No patient with IPF presented with > 25% lymphocytes in BAL. In 6/15 (40%) of the HP cases, the percentage of lymphocytes was < 25%. A total of 56 participants (62%) displayed HRCT findings that were indicative of fibrosis. In those cases the percentage of lymphocytes was 10.1 (IQR = 6.1-18.0) as compared with 20.2% (IQR = 9.7-37.5) of those 35 cases without fibrosis (p = 0.007). In patients with fibrosis in HRCT, the percentage of neutrophils was 11.3 (IQR = 4.1-21.4) as compared with 3.8 (IQR = 1.4-3.8) in those without fibrosis (p = 0.009).

CONCLUSION

Several patterns in differential cytology are observed in common ILDs. The presence of fibrosis has an impact on these findings.

Workers' compensation for occupational respiratory diseases

The respiratory system is one of the most important body systems particularly from the viewpoint of occupational medicine because it is the major route of occupational exposure. In 2013, there were significant changes in the specific criteria for the recognition of occupational diseases, which were established by the Enforcement Decree of the Industrial Accident Compensation Insurance Act (IACIA). In this article, the authors deal with the former criteria, implications of the revision, and changes in the specific criteria in Korea by focusing on the 2013 amendment to the IACIA. Before the 2013 amendment to the IACIA, occupational respiratory disease was not a category because the previous criteria were based on specific hazardous agents and their health effects. Workers as well as clinicians were not familiar with the agent-based criteria. To improve these criteria, a system-based structure was added. Through these changes, in the current criteria, 33 types of agents and 11 types of respiratory diseases are listed under diseases of the respiratory system. In the current criteria, there are no concrete guidelines for evaluating work-relatedness, such as estimating the exposure level, latent period, and detailed examination methods. The results of further studies can support the formulation of detailed criteria.

[Clinical morphology of hypersensitivity pneumonitis]

The article presents a viewpoint on morphogenesis types of dust pulmonary diseases and details clinical morphology of hypersensitivity pneumonitis, based on lung biopsy studies in industrial workers.

Severe hypersensitivity pneumonitis associated with everolimus therapy for neuroendocrine tumour: a case report

BACKGROUND

Novel therapeutic agents are currently being investigated for neuroendocrine tumour treatment.

CASE PRESENTATION

We report here on the case of a patient presenting with hypersensitivity pneumonitis while being treated with everolimus, a mammalian target of rapamycin (mTOR) inhibitor.

CONCLUSION

Side effects of everolimus should be familiar to clinicians, including nonspecialists, and be monitored carefully to allow for prompt management.

High-resolution computed tomography findings for patients with drug-induced pulmonary toxicity, with special reference to hypersensitivity pneumonitis-like patterns in gemcitabine-induced cases

BACKGROUND

Gemcitabine (GEM) is widely used as a chemotherapeutic agent. However, pulmonary toxicity has been rarely observed with GEM use. This article aims to determine the incidence and causes of drug-induced pulmonary toxicity, and to classify the high-resolution computed tomography (HRCT) findings for antitumor therapy-associated pulmonary toxicity based on characteristic patterns and pathological considerations, with a special focus on GEM-associated pulmonary toxicity (GAPT).

METHODS

Medical records of all patients with drug-induced pulmonary toxicity seen at Kyorin University hospital between April 2006 and December 2011 were retrospectively reviewed. The study examined correlations between HRCT and the assessed pathological or clinical findings, with a specific focus on antitumor drugs.

RESULTS

We identified 66 patients with drug-induced pulmonary toxicity. Among the antitumor drugs, GEM was the primary offending agent (n = 8) for pulmonary toxicity followed by docetaxel and gefitinib. HRCT patterns for the eight GAPT patients included the non-specific interstitial pneumonia (NSIP; n = 5) and the hypersensitivity pneumonitis (HP)-like pattern (n = 3). In contrast, four patients in the study were found to have the HP-like pattern, with three cases associated with GEM and one case associated with imatinib mesylate. The transbronchial lung biopsy or video-assisted thoracic surgery specimens for these patients showed granuloma or organizing tissue with a random distribution that was independent of the respiratory bronchiole. These results appeared to correspond to the HRCT-determined centrilobular nodules.

CONCLUSION

GEM was the leading cause of drug-induced pulmonary toxicity in the patients examined in this study. This toxicity appears as NSIP or an HP-like pattern during HRCT examinations. This HP-like pattern may be useful for diagnosing GEM-induced pulmonary toxicity, as well as demonstrating granuloma or organizing tissue during lung pathology examinations.

[Clinical characteristic analysis of 96 cases of hypersensitivity pneumonitis]

OBJECTIVE

To improve understanding of the clinical characteristics and diagnosis of hypersensitivity pneumonitis (HP).

METHODS

We retrospectively analyzed the clinical data, including clinical symptoms, laboratory tests, exposure, pulmonary function tests, chest CT imaging and cytological classification of bronchoalveolar lavage (BAL) of 96 patients with HP from Jan 2001 to Jun 2011 in Peking Union Medical College Hospital. We divided the patients into 2 groups: a pathologically-confirmed group and a clinically-suspected group.

RESULTS

There were 58 females and 41 males. The median age at the diagnosis was 53 years. The most common exposures were low-molecular-weight chemicals (42.7%) and animal proteins (37.5%). Common clinical symptoms included dyspnea on exertion (90.6%) and cough (76.0%). Pulmonary function test showed diffusion abnormality (73.5%) and restrictive ventilatory impairment (59.7%). Chest CT scan revealed patchy or diffuse bilateral ground-glass opacities (64.6%), centrilobular nodules (21.9%), and air trapping (15.6%). Reticulation (45.8%), traction bronchiectasis (21.9%) and honeycombing(9.4%) were present in chronic HP. BAL lymphocyte counts > 0.2 and CD4/CD8 < 0.9 were more commonly seen in patients with a disease course of less than 1 year. The pathologically-confirmed group and the clinically-suspected group shared many similar characteristics including age at diagnosis, gender, clinical manifestation, pulmonary function impairments and imaging findings, but significant differences existed in certain parameters. In the pathologically- confirmed group, the duration of disease was longer (24 months vs 6 months, Z = -2.492, P = 0.013) and clubbed fingers were more common (23.4% vs 8.2%, χ(2) = 4.227, P = 0.040). Diffusion abnormality was present in more patients of this group (90.7% vs 44.0%, χ(2) = 35.219, P < 0.01). By CT scan, reticulation, traction bronchiectasis and honeycombing (57.5% vs 26.5%, χ(2) = 9.434, P < 0.01) were more evident as compared to the clinically-suspected group. The value of transbronchial lung biopsy for diagnosing HP was limited, with a positive result of only 8.2%. Surgical lung biopsy was needed in uncertain cases.

CONCLUSION

The diagnosis of HP was difficult. In some cases a clinical diagnosis can be made by combination of history of exposure, CT manifestations and cell classification of BAL. For atypical cases a multi-disciplinary approach including pathologists, radiologists and pulmonologists is needed.

[Clinicopathological diagnosis of hypersensitivity pneumonitis]

OBJECTIVE

To enhance the understandings of clinical, radiological and pathological features of hypersensitivity pneumonitis (HP).

METHODS

Six HP cases with pathological data, clinical and radiological data were retrospectively analyzed during the period from February 2009 to September 2011 at Beijing Hospital of Ministry of Health. There were 2 males and 4 females with a mean age of 51.5 years (range: 38-61). Clinically, the patients presented with chronic cough, shortness of breath and dyspnea (n = 2). The disease course was 1-8 months. Five cases had fed pigeons and other contact histories. Specimens obtained by transbronchial lung biopsy (n = 3) and open lung biopsy (n = 3) were paraffin embedded and stained by hematoxylin and eosin, special stains and immunohistochemistry.

RESULTS

Four cases had subacute HP and 2 cases chronic HP. Three cases of subacute HP underwent transbronchial lung biopsy. One case of subacute HP and 2 cases of chronic HP were diagnosed by open lung biopsy. High-resolution computed tomography of lungs showed diffuse ground glass and patch shadow along the bronchial and centrilobular distributions. There was a predominance of upper half zone. Typical visible mosaic syndrome was present. There was poorly formed granuloma without cheesy necrosis. With an insidious medical history and complicated radiological features, chronic HP cases were characterized by pulmonary interstitial fibrosis. There were usual interstitial pneumonitis (UIP)-like fibrosis and fibrosis with an airway-centered distribution type. The lesions were distributed around bronchioles. Continuous bridge fibrosis might be present. There were bronchiolar metaplasia of peribronchiolar alveoli, poorly formed granuloma and multinucleated giant cells in interstitium. Schaumann body was identified in 1 case.

CONCLUSIONS

Because of its diverse clinical, radiological and pathological features, HP may be easily confused with other interstitial lung diseases. Aggregate analyses yield a definite diagnosis.

Proteome analysis of bronchoalveolar lavage fluid in chronic hypersensitivity pneumonitis

BACKGROUND

Hypersensitivity pneumonitis (HP) is an immune-mediated lung disease induced by inhalation of numerous antigens. Pathologically, chronic HP tends to show usual interstitial pneumonia (UIP) and fibrotic nonspecific interstitial pneumonia (fNSIP) patterns. Patients with UIP pattern present insidious onset and a risk for acute exacerbations.

METHODS

To evaluate the proteomic differences of bronchoalveolar lavage fluid (BALF) between UIP and fNSIP patterns, BALF from seven patients with UIP pattern and four patients with fNSIP pattern was examined using two-dimensional gel electrophoresis and mass spectrometry.

RESULTS

By individually comparing each BALF sample, we found that the protein levels of surfactant protein A (SP-A), immunoglobulin heavy chain α, α-2 heat shock glycoprotein, haptoglobin β, and immunoglobulin J chain were significantly higher in the patients with UIP pattern than those in the patients with fNSIP pattern. In contrast, the protein levels of glutathione s-transferase, vitamin D-binding protein, and β-actin were significantly higher in the patients with fNSIP pattern than those in the patients with UIP pattern. To confirm the results of SP-A in the BALF proteome, we performed enzyme-linked immunosorbent assay in a larger group. The concentrations of SP-A in BALF from the patients with UIP pattern were significantly higher than those from the patients with fNSIP pattern (2.331 ± 1.656 μg/ml vs. 1.319 ± 1.916 μg/ml, p = 0.034).

CONCLUSIONS

We identified several proteins that may play roles in the development of pathological differences between UIP and fNSIP patterns of chronic HP.

[Pathologic diagnosis and clinical analysis of chronic extrinsic allergic alveolitis]

OBJECTIVE

To study the clinicopathologic features and diagnostic approach of chronic extrinsic allergic alveolitis (EAA).

METHODS

Seven cases of chronic EAA diagnosed by open lung biopsy or lung transplant were enrolled into the study. The clinical and pathologic features were analyzed and the literature was reviewed.

RESULTS

There were altogether 4 men and 3 women. The age of the patients ranged from 30 to 65 years (mean = 48 years). All cases represented chronic form and five cases diagnosed by open lung biopsy also showed features of recent aggravation, leading to hospitalization. Four cases had known history of exposure to inciting gases, pollens and pets, and only 2 cases were positive for allergens. High-resolution CT scan showed ground-glass attenuation and reticular pattern that often had a patchy distribution and central predominance. Bronchoalveolar lavage analysis showed marked lymphocytosis, with CD4(+)/CD8(+) ratio less than 1. Lung function test demonstrated a restrictive ventilatory defect, with decreased compliance, reduced diffusion capacity and high airway obstruction. Five cases had open lung biopsy performed and two cases had undergone lung transplantation. Pathologic examination showed bronchiolocentric cellular interstitial pneumonia, interstitial fibrosis, non-caseating epithelioid granulomas, epithelioid histiocytic infiltrate in the respiratory bronchioles and intraluminal budding fibrosis. The five cases with open lung biopsy performed also showed neutrophilic infiltrate in the alveoli. The two lung transplant cases were complicated by severe fibrotic changes.

CONCLUSIONS

Chronic EAA demonstrates characteristic pathologic features. Definitive diagnosis requires correlation with clinical and radiologic findings due to possible morphologic mimicry of other diffuse parenchymal lung diseases.

Simple flow cytometric protocol of CD4+/CD8+ lymphocyte ratio assessment in bronchoalveolar lavage fluids from patients with interstitial lung diseases

OBJECTIVE

To validate the fast and accurate flow cytometric (FCM) protocol using blood-standardized antibodies for alveolar lymphocyte subtyping with respect to standard immunocytochemistry (IC).

STUDY DESIGN

FCM and IC were applied to immunophenotype T cell subsets in bronchoalveolar lavage (BAL) fluids from patients with interstitial lung diseases. Diagnostic BAL specimens from 50 patients with suspected sarcoidosis, idiopathic pulmonary fibrosis, and hypersensitivity pneumonitis were evaluated by both IC and FCM. In FCM, CD4+ and CD8+ T cells were identified by light scatter gating with CD3 selection using basic tricolor cytometer.

RESULTS

Relative amounts of CD4+, CD8+ T cells, and CD4+/CD8+ ratios demonstrated by the FCM showed excellent, significant correlations with IC results. FCM values did not differ significantly from IC results. However, the sensitivity and specificity of conventional IC staining were not sufficient to assess CD4+/ CD8+ ratio in most idiopathic pulmonary fibrosis cases. Additionally, performing IC immunophenotyping in BAL samples with low lymphocyte content introduced a remarkable error into CD4+/CD8+ ratio assessment.

CONCLUSION

FCM allowed reliable, precise, and fast T-cell subset measurement in all BAL samples, overcoming the IC disadvantages. Our validated FCM protocol provides diagnostically relevant CD4+/CD8+ ratio determination by simple light scatter gating strategy with CD3 selection.

[Malignant lymphoma of lung with hypersensitivity pneumonitis]

We report a resected case of malignant lymphoma with hypersensitivity pneumonitis. A 62-year-old woman, who presented with fever, wheeze and dry cough was referred to our department under the diagnosis of malignant B cell lymphoma in lower lobe of the left lung and hypersensitivity pneumonitis. She underwent left lower lobectomy as a therapy for malignant lymphoma. Pathological findings showed multiple small nodules macroscopically, which was observed as bronchiolocentric interstitial pneumonitis with lymphocytes microscopically. Post operative course was uneventful and no sign of acute exacerbation was seen. It is rare that lung with hypersensitivity pneumonitis is observed as a macroscopical specimen. Hypersensitivity pneumonitis differs from idiopathic pulmonary fibrosis, but we have to take care of post operative course because post operative acute exacerbation was reported.

Mouse model of hypersensitivity pneumonitis after inhalation exposure to different microbial antigens associated with organic dusts

The aim of this study was to reproduce in laboratory conditions hypersensitivity pneumonitis (HP) pathogenesis in a new animal model predictive of the human response, and to select the microbial antigen associated with organic dust that exerts the strongest pathogenic effect on the respiratory organ. To achieve this goal, mice of the strain C57BL/6J prone to fibrosis were exposed for 1 hour daily up to 28 days to the inhalation of aerosols of each of the 5 microbial components of organic dusts whose conjunction with the occurrence of HP has been confirmed by numerous authors: Pantoea agglomerans saline extract (SE), P. agglomerans microvesicle-bound endotoxin, Saccharopolyspora rectivirgula SE, Aspergillus fumigatus SE, saline extract of dust from a grain sample overgrown with S. rectivirgula and Thermoactinomyces vulgaris, and a saline solvent (PBS) was used as a control. Exposure of the animals to organic dust components was conducted using a novel inhalation challenge set. Lung samples were collected from untreated mice and from mice exposed for 7 and 28 days, and examined by digitalized histopathology and biochemistry for the presence of inflammatory changes and fibrosis. P. agglomerans SE appeared to be the sole antigen which evoked a statistically significant fibrosis and a significant increase of hydroxyproline in the lungs of mice exposed for 28 days to this extract, both compared to the mice untreated and to those exposed to the solvent. P. agglomerans SE also evoked the strongest and statistically significant inflammatory response in the lungs of the mice, both after 7 and 28 days of exposure. After 7 days, significant inflammatory changes were also found in mice exposed to A. fumigatus SE, and after 28 days in mice exposed to all antigens. In conclusion, our results allow us to define a useful animal model of HP which can be a supplement for now commonly used bleomycin model. This model should comprise: present set of instruments for inhalation, mice of the line C57BL/6J and the saline extract of P. agglomerans as the antigen. For a better understanding of the presented results, a detailed study covering immunological investigations, focused on the mechanism of antigen action, are needed.

Cathepsin-K is a sensitive immunohistochemical marker for detection of micro-granulomas in hypersensitivity pneumonitis

Hypersensitivity Pneumonitis (HP) is an interstitial lung disease that occurs upon exposure to a variety of inhaled organic antigens. The presence of small non-caseating granulomas and isolated giant cells is not specific, but is considered a relevant histological feature for HP. The detection of granulomas is widely considered as easy on standard histological stains, but microgranuloma detection can be difficult and/or time consuming, especially in chronic HP cases. Cathepsin K (Cath-K) is a potent cysteine protease expressed at high levels in activated macrophages (osteoclasts, and epithelioid cells in granulomas), but is not expressed in resident macrophages thus representing a promising marker to rapidly detect and quantitatively evaluate microgranulomas in interstitial lung diseases. We analyzed the expression of Cath-K by immunohistochemistry in 22 subacute and chronic HP cases, using semi-quantitative scores. Control samples included normal lung tissue, and a variety of interstitial lung diseases: 3 Wegener's granulomatosis, 3 sarcoidosis, 3 tuberculosis, 1 berylliosis, 20 idiopathic pulmonary fibrosis (IPF), 2 Langerhans' cell histiocytosis, 5 nonspecific-interstitial pneumonia (NSIP), 5 cryptogenic organising-pneumonia (COP), 2 Airway-Centered Interstitial Fibrosis (ACIF), 5 desquamative interstitial pneumonia (DIP), 3 respiratory bronchiolitis interstitial lung disease (RB-ILD). Intense expression of Cath-K was demonstrated in epithelioid and giant cells in all cases containing granulomas (HP, sarcoidosis, Wegener's granulomatosis, berylliosis, tuberculosis). Among HP cases 19/22 (86.3%) contained granulomas that could be semiquantitatively evaluated. In all HP and control cases alveolar macrophages did not express Cath-K, including cases characterised by large collections of alveolar macrophages such as DIP and RB-ILD.

CONCLUSIONS

Cath-K represents a sensitive and specific marker to detect and quantitate granulomatous reactions in interstitial lung diseases, and is particularly useful in chronic HP cases.

[Chest high resolution CT features of extrinsic allergic alveolitis and its diagnostic value]

OBJECTIVE

To summarize the chest high-resolution CT (HRCT) features of the patients with extrinsic allergic alveolitis (EAA).

METHODS

We analyzed the images of chest HRCT of 34 patients diagnosed as EAA at our hospital from February 2001 to August 2009.

RESULTS

All patients had a history of environmental exposure. The duration of intermittent or continuous antigen exposure was from 3 months to 13 years. Two patients showed acute clinical manifestations. There were 22 sub-acute and 10 chronic cases. Acute EAA was characterized by ground-glass opacities, air trapping and/or mosaic sign on HRCT. The HRCT features of subacute EAA included patchy ground-glass opacities with mosaic sign (n = 11, 50.0%) and diffusely distributed centrilobular nodules (n = 7, 31.8%) with mosaic sign (n = 4, 18.2%). All patients with chronic EAA had reticular and honeycombing lesions on HRCT. There were 3 cases with ground-glass opacities, 3 with mosaic sign, and 3 with centrilobular nodules.

CONCLUSION

The typical findings of chest HRCT are helpful for making a diagnosis and differential diagnosis of EAA.

General aspects of hypersensitivity pneumonitis in Turkey

Hypersensitivity pneumonitis prevalence rates are between 5 and 15% of the overall population exposed to known inciting antigens but a small number of cases have been reported from Turkey until now. We aimed to present a broad picture of hypersensitivity pneumonitis in Turkey, thus promoting interest in this relatively common disease in developing countries. Search engines were utilized to retrieve the cases reported from Turkey. Other published journals and meeting abstracts which have not been registered into electronic databases were manually reviewed. Twenty-two cases from 13 reports were characterized by demographics, clinical features, occupational and environmental exposures, diagnostic tools and prognostic data. The majority of the group consisted of women (68.2%) and had a positive history for contact with an avian (59%). Mean exposure period was 69 ± 77.6 months. The most common reported clinical form was chronic hypersensitivity pneumonitis (58.8%). Reticulonodular pattern was the basic pathological finding (45%). Restrictive impairments of the forced vital capacity (FVC) and carbon monoxide diffusing capacity (DLCO) of the lungs were the basic pathologies observed in pulmonary function tests. Interstitial fibrosis was the most common pathological finding (61.5%). Few cases reported with preponderance of chronic hypersensitivity pneumonitis with avian exposure from 70 million populations suggest that many hypersensitivity pneumonitis cases, especially acute forms, have been ignored. Also, hypersensitivity pneumonitis somehow appears to be a neglected occupational disease. The present situation should be considered as a common problem currently faced by developing countries and occupational groups under risk must be investigated promptly.

[Modifications of the cytoimmunological pattern of bronchoalveolar lavage (BAL) material caused by cigarette smoking in selected lower air-way diseases]

INTRODUCTION

In the last years we have used flow cytometry as an auxiliary diagnostic tool in alveolar lymphocyte (i.e. originating from BAL) phenotyping in more than 500 persons suspected for lower airways pathology.

MATERIAL AND METHODS

In the study we compared the results of 1) BAL lymphocyte typing by flow cytometry, 2) cytological examination, respectively, in nonsmoking/smoking (NS/S) patients with lung sarcoidosis, n = 56/31, extrinsic allergic alveolitis (EAA), n = 9/5, silicosis, n = 15/18, idiopathic pulmonary fibrosis (IPF), n = 20/7, and pulmonary tuberculosis (TBC), n = 7/6. The results were related to the volume of BAL fluid recovery (higher value reflects the dominance of lower airways content versus bronchial content).

RESULTS

In smoking patients, in comparison with respective NS, significantly higher total BAL cell numer (except TBC), higher macrophage percentage, lower lymphocyte percentage and lower CD4/CD8 ratio (except EAA) was found. CD4/CD8 results: 8.26 +/- 0.52 (NS) vs 4.29 +/- 0.65 (S) in sarcoidosis (p < 0.001), 1.18 +/- 0.44 (NS) vs 0.99 +/- 0.43 (S) in IPF (p < 0.05), 1.79 +/- 0.22 (NS) vs 0.73 +/- 0.11 (S) in silicosis (p < 0.001) and 1.64 +/- 0.57 vs 0.88 +/- 0.1 in TBC (p < 0.05). Additionally, cigarette smoking modified BAL pattern: 1. in sarcoidosis and silicosis lower CD4+ cell and higher CD8+ cell percentage; 2. in IPF increase in neutrophil percentage; 3. in TBC higher neutrophil and eosinophil percentage. Both in NS and S, BAL fluid recovery rate is significantly positively correlated with CD4/CD8 ratio and total BAL CD3+ cell number and negatively with BAL CD8+ cell percentage.

CONCLUSIONS

Interpreting of BAL material cytoimmunology pattern should take into account data on cigarette smoking and BAL fluid recovery rate. The results obtained in the study may reflect more severe disease course in IPF and TBC.

[Two cases of summer-type hypersensitivity peumonitis with remarkable changes in the bronchioles]

A 56-year-old man and a 53-year-old woman with cough, sputum and dyspnea were admitted in the summer. High-resolution computed tomographic findings of the chest showed centrilobular branching opacities like diffuse panbronchiolitis with ground glass opacities. Both cases showed hypoxia, a high titer of serum anti-Tricosporon antibody and exacerbation in their own homes. Video-assisted thoracoscopic lung biopsy revealed granuloma in the bronchioles area. We diagnosed summer type hypersensitivity pneumonitis and this condition improved in response to antigen isolation and steroids. Remarkable changes in the bronchioles were characteristic in the two cases.