Desquamative interstitial pneumonia: a systematic review of its features and outcomes

Anti-annexin A4 antibody as a biomarker for desquamative interstitial pneumonia

Desquamative interstitial pneumonia (DIP), a rare type of idiopathic interstitial pneumonia (IIP), is smoking-related. However, some cases of DIP can also occur in non-smokers with autoimmune disorders. The diagnosis of DIP requires an invasive surgical lung biopsy, therefore, identifying a non-invasive diagnostic biomarker for DIP is crucial. This study aimed to elucidate autoantibodies specific for DIP and evaluate their diagnostic utility. Autoantibodies in the sera of patients with DIP were screened using immunoprecipitation. The common proteins recognized by autoantibodies in patients with DIP were identified using mass spectrometry and enzyme-linked immunosorbent assay (ELISA), and compared to other types of interstitial lung diseases (ILD) and pulmonary diseases. Several characteristic proteins commonly recognized by the sera of patients with DIP were revealed using immunoprecipitation and these proteins were identified as annexin A (ANXA) proteins using mass spectrometry. Using ELISA, autoantibodies to several ANXA were detected more frequently and specifically in DIP compared with those with other types of ILDs and pulmonary diseases. In particular, anti-ANXA4 antibodies had a sensitivity of 52.6 % and specificity of 99 % for DIP compared with those of other types of ILD. Therefore, anti-ANXAs antibodies, especially anti-ANXA4, could be a candidate diagnostic biomarker for DIP.

Smoking-Related Interstitial Lung Disease and Emphysema

Diagnosis and treatment of patients with smoking-related lung diseases often requires multidisciplinary contributions to optimize care. Imaging plays a key role in characterizing the underlying disease, quantifying its severity, identifying potential complications, and directing management. The primary goal of this article is to provide an overview of the imaging findings and distinguishing features of smoking-related lung diseases, specifically, emphysema/chronic obstructive pulmonary disease, respiratory bronchiolitis-interstitial lung disease, smoking-related interstitial fibrosis, desquamative interstitial pneumonitis, combined pulmonary fibrosis and emphysema, pulmonary Langerhans cell histiocytosis, and E-cigarette or vaping related lung injury.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.

Weight loss with GLP-1 analogues in preparation for transplantation

This case describes a woman in her 20s with a 6-month history of progressive exertional dyspnoea and cough. Examination revealed hypoxia on room air, sinus tachycardia, finger clubbing and bibasal inspiratory crackles. Inflammatory markers were mildly elevated and empirical antimicrobial therapy was commenced. A multidisciplinary discussion consensus diagnosis of acute interstitial pneumonitis was made based on the findings of high-resolution CT of the chest, macrophage predominant bronchoalveolar lavage cell differential and surgical lung biopsy. There was clinical and radiological deterioration despite glucocorticoids and antifibrotic therapy. A body mass index of 37.5 kg/m2 precluded her from lung transplant assessment and consideration. Following consultation with the weight management service, she was commenced on glucagon-like peptide 1 (GLP-1) analogue therapy. She had a remarkable response within 6 months, was listed for lung transplantation, and within 18 months of her initial presentation, a double lung transplantation was performed.

Desquamative Interstitial Pneumonia with Progressive Pulmonary Fibrosis

A 70-year-old man who smoked was referred to our hospital because of progressive cough and dyspnea. Radiologic images showed ground-glass attenuation predominantly in the lower lung lobes. A surgical lung biopsy was performed, and a diagnosis of desquamative interstitial pneumonia (DIP) was made. The patient's symptoms improved with smoking cessation and steroid treatment, but the ground-glass attenuation did not completely resolve. At 10 years after the diagnosis, the fibrotic lesions deteriorated and treatment with nintedanib was subsequently initiated. Careful observation is needed in patients with DIP whose lung involvement does not completely improve with initial treatment.

Lethal eosinophilic crystalline pneumonia in mice expressing a stabilized Csf2 mRNA

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that stimulates the proliferation and differentiation of granulocyte and macrophage precursors. The mouse gene-encoding GM-CSF, Csf2, is regulated at both transcriptional and post-transcriptional levels. An adenine-uridine-rich element (ARE) within the 3'-untranslated region of Csf2 mRNA was shown in cell transfection studies to confer instability on this transcript. To explore the physiological importance of this element in an intact animal, we generated mice with a knock-in deletion of the 75-nucleotide ARE. Mice heterozygous for this ARE deletion developed severe respiratory distress and death within about 12 weeks of age. There was dense infiltration of lung alveolar spaces by crystal-containing macrophages. Increased stability of Csf2 mRNA was confirmed in bone marrow-derived macrophages, and elevated GM-CSF levels were observed in serum and lung. These mice did not exhibit notable abnormalities in blood or bone marrow, and transplantation of bone marrow from mutant mice into lethally irradiated WT mice did not confer the pulmonary phenotype. Mice with a conditional deletion of the ARE restricted to lung type II alveolar cells exhibited an essentially identical lethal lung phenotype at the same ages as the mice with the whole-body deletion. In contrast, mice with the same conditional ARE deletion in myeloid cells, including macrophages, exhibited lesser degrees of macrophage infiltration into alveolar spaces much later in life, at approximately 9 months of age. Post-transcriptional Csf2 mRNA stability regulation in pulmonary alveolar epithelial cells appears to be essential for normal physiological GM-CSF secretion and pulmonary macrophage homeostasis.

Sequence of Rare Diagnoses in a Young Patient: Altitude Barotrauma Hemopneumothorax and Desquamative Interstitial Pneumonia

We present the case of a 35-year-old patient without pathological history who developed hemopneumothorax due to altitude barotrauma during a commercial airline flight. The computed tomography (CT) of the chest identified the presence of right hydropneumothorax and emphysema "blebs" and bubbles. After the therapeutic insertion of a drain tube, the patient returned to the country by land transport. Three weeks later, he was diagnosed with right-sided pleurisy based on a CT scan with contrast material. A surgical intervention was then performed, and three biopsy samples were taken; the histopathological result highlighted suggestive elements for the diagnosis of desquamative interstitial pneumonia (DIP).

Smoking-Related Interstitial Lung Diseases

Smoking-related interstitial lung diseases (ILDs) are a group of heterogeneous, diffuse pulmonary parenchymal disease processes associated with tobacco exposure. These disorders include pulmonary Langerhans cell histiocytosis, respiratory bronchiolitis-associated ILD, desquamative interstitial pneumonia, acute eosinophilic pneumonia, and combined pulmonary fibrosis and emphysema. This review summarizes the current evidence of pathogenesis, clinical manifestations, diagnostic approach, prognosis, and treatment modalities for these diseases. We also discuss the interstitial lung abnormalities incidentally detected in radiologic studies and smoking-related fibrosis identified on lung biopsies.

CANNOT B UIP

The American Thoracic Society provides guidelines for the confident radiographic diagnosis of UIP. In addition, the guidelines identify findings on CT scans that should suggest an alternative diagnosis to UIP. These findings include consolidation, air trapping, nodules, ground glass opacities, cysts, and upper lung and bronchovascular distribution. We present a mnemonic to help the reader remember the list of findings that are inconsistent with UIP and provide imaging examples for completeness. The mnemonic is "CANNOT B" UIP.

Inescapable Fibrosis: The Development of Desquamative Interstitial Pneumonia Post-Lung Transplantation Performed for a Patient with Idiopathic Pulmonary Fibrosis

Interstitial lung disease is characterised by a combination of cellular proliferation, inflammation of the interstitium and fibrosis within the alveolar wall. A 58-year-old man was referred for lung transplantation after developing worsening dyspnoea and progressive hypoxaemic respiratory failure from idiopathic pulmonary fibrosis. Three years later, he developed desquamative interstitial pneumonia in his transplanted lungs, and despite augmentation of immune suppression, he had a progressive decline in his lung function and exercise capacity. Interestingly, in our case, the histopathology obtained post transplant strongly goes against the recurrence of usual interstitial pneumonia/idiopathic pulmonary fibrosis; rather, two separate interstitial disease processes have been identified.

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

Recurrence of primary disease following lung transplantation

Lung transplant has become definitive treatment for patients with several end-stage lung diseases. Since the first attempted lung transplantation in 1963, survival has significantly improved due to advancement in immunosuppression, organ procurement, ex vivo lung perfusion, surgical techniques, prevention of chronic lung allograft dysfunction and bridging to transplant using extracorporeal membrane oxygenation. Despite a steady increase in number of lung transplantations each year, there is still a huge gap between demand and supply of organs available, and work continues to select recipients with potential for best outcomes. According to review of the literature, there are some rare primary diseases that may recur following transplantation. As the number of lung transplants increase, we continue to identify disease processes at highest risk for recurrence, thus shaping our future approaches. While the aim of lung transplantation is improving survival and quality of life, choosing the best recipients is crucial due to a shortage of donated organs. Here we discuss the common disease processes that recur and highlight its impact on overall outcome following lung transplantation.

Sex and gender in interstitial lung diseases

Sex and gender differences influence key domains of research, lung health, healthcare access and healthcare delivery. In interstitial lung diseases (ILDs), mouse models of pulmonary fibrosis are clearly influenced by sex hormones. Additionally, short telomeres, a biomarker of telomere regulation gene mutations, are impacted by sex, while heritability unexplained by genetic variation may be attributable to gendered environmental factors that drive epigenetic control. Diseases like idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, occupational ILDs, connective tissue-associated ILDs and lymphangioleiomyomatosis have different prevalence and prognosis between men and women. These differences arise from a complex interplay between biological sex and sociocultural gender influencing genetics, epigenomic modifiers, hormones, immune function, response to treatment and interaction with healthcare systems. Much work remains to be done to systematically integrate sex and gender analysis into relevant domains of science and clinical care in ILD, from strategic considerations for establishing research priorities to guidelines for establishing best clinical practices. Accounting for sex and gender in ILD is essential to the practice of individualised, patient-centred medicine.

Fibrotic Idiopathic Interstitial Lung Disease: The Molecular and Cellular Key Players

Interstitial lung diseases (ILDs) that are known as diffuse parenchymal lung diseases (DPLDs) lead to the damage of alveolar epithelium and lung parenchyma, culminating in inflammation and widespread fibrosis. ILDs that account for more than 200 different pathologies can be divided into two groups: ILDs that have a known cause and those where the cause is unknown, classified as idiopathic interstitial pneumonia (IIP). IIPs include idiopathic pulmonary fibrosis (IPF), non-specific interstitial pneumonia (NSIP), cryptogenic organizing pneumonia (COP) known also as bronchiolitis obliterans organizing pneumonia (BOOP), acute interstitial pneumonia (AIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), and lymphocytic interstitial pneumonia (LIP). In this review, our aim is to describe the pathogenic mechanisms that lead to the onset and progression of the different IIPs, starting from IPF as the most studied, in order to find both the common and standalone molecular and cellular key players among them. Finally, a deeper molecular and cellular characterization of different interstitial lung diseases without a known cause would contribute to giving a more accurate diagnosis to the patients, which would translate to a more effective treatment decision.

Ground-glass opacity (GGO): a review of the differential diagnosis in the era of COVID-19

Thoracic imaging is fundamental in the diagnostic route of Coronavirus disease 2019 (COVID-19) especially in patients admitted to hospitals. In particular, chest computed tomography (CT) has a key role in identifying the typical features of the infection. Ground-glass opacities (GGO) are one of the main CT findings, but their presence is not specific for this viral pneumonia. In fact, GGO is a radiological sign of different pathologies with both acute and subacute/chronic clinical manifestations. In the evaluation of a subject with focal or diffuse GGO, the radiologist has to know the patient’s medical history to obtain a valid diagnostic hypothesis. The authors describe the various CT appearance of GGO, related to the onset of symptoms, focusing also on the ancillary signs that can help radiologist to obtain a correct and prompt diagnosis.

Diagnostic performance of chest CT in differentiating COVID-19 from other causes of ground-glass opacities

Background

To evaluate the diagnostic performance of chest CT in differentiating coronavirus disease 2019 (COVID-19) and non-COVID-19 causes of ground-glass opacities (GGO).

Results

A total of 80 patients (49 males and 31 females, 46.48 ± 16.09 years) confirmed with COVID-19 by RT-PCR and who underwent chest CT scan within 2 weeks of symptoms, and 100 patients (55 males and 45 females, 48.94 ± 18.97 years) presented with GGO on chest CT were enrolled in the study. Three radiologists reviewed all CT chest exams after removal of all identifying data from the images. They expressed the result as positive or negative for COVID-19 and recorded the other pulmonary CT features with mention of laterality, lobar affection, and distribution pattern. The clinical data and laboratory findings were recorded. Chest CT offered diagnostic accuracy ranging from 59 to 77.2% in differentiating COVID-19- from non-COVID-19-associated GGO with sensitivity from 76.25 to 90% and specificity from 45 to 67%. The specificity was lower when differentiating COVID-19 from non-COVID-19 viral pneumonias (30.5–61.1%) and higher (53.1–70.3%) after exclusion of viral pneumonia from the non-COVID-19 group. Patients with COVID-19 were more likely to have lesions in lower lobes (p = 0.005), peripheral distribution (p < 0.001), isolated ground-glass opacity (p = 0.043), subpleural bands (p = 0.048), reverse halo sign (p = 0.005), and vascular thickening (p = 0.013) but less likely to have pulmonary nodules (p < 0.001), traction bronchiectasis (p = 0.005), pleural effusion (p < 0.001), and lymphadenopathy (p < 0.001).

Conclusions

Chest CT offered reasonable sensitivity when differentiating COVID-19- from non-COVID-19-associated GGO with low specificity when differentiating COVID-19 from other viral pneumonias and moderate specificity when differentiating COVID-19 from other causes of GGO.

Hallazgos similares al COVID-19 en un caso fatal de neumonía intersticial descamativa asociada con glomerulonefritis por IgA en una niña de 13 meses de edad

En la era del COVID-19, es usual sospechar que cualquier paciente con síndrome respiratorio agudo grave (SARS) esté asociado con una infección por SARS-CoV-2. El objetivo de este artículo es presentar un caso de neumonía similar al COVID, con evolución fatal. Los aspectos clínicos se correlacionan con los hallazgos en la autopsia y se discuten en el contexto de los datos más recientes en la literatura médica. Una niña de 13 meses de edad ingresó a la sala de emergencias con dificultad respiratoria aguda y opacidades pulmonares bilaterales con apariencia de vidrio molido, además del pulmón izquierdo casi completamente opacificado. El estado de la paciente se deterioró súbitamente, y se confirmó la muerte 3 h después de la admisión. En la autopsia se diagnosticó neumonía intersticial descamativa grave, y se asoció con glomerulonefritis por IgA, un hallazgo poco usual. No se detectó infección por SARS-CoV-2 en el parénquima pulmonar mediante RT-PCR. Éste es un caso muy inusual de deterioro rápido de un infante con neumonía intersticial descamativa (NID) idiopática y afectación multiorgánica. Con base en tinciones inmunohistoquímicas, proponemos la hipótesis de que, en la NID, las membranas hialinas surgen de neumocitos descamados necrotizantes. En la era de COVID-19, tales casos son extremadamente difíciles de diagnosticar, y pueden semejar las lesiones pulmonares inducidas por el SARS-CoV-2. Esta pauta de formación de membrana hialina podría explicar la falta de respuesta a la terapia con oxígeno. El presente caso resalta la importancia de la autopsia en estos casos complicados.

COVID-19 Like Findings in a Fatal Case of Idiopathic Desquamative Interstitial Pneumonia Associated With IgA Glomerulonephritis in a 13-Month-Old Child

In the COVID-19 era, patients with severe acute respiratory syndrome (SARS) are suspected to be associated with SARS-CoV-2 infection. The aim of this paper is to present a case with COVID-like pneumonia, with fatal evolution. The clinical aspects were correlated with the autopsy findings and discussed on the background of the most recent data from the medical literature. A 13-month-old girl was admitted to the emergency room with acute severe shortness of breath and pulmonary bilateral ground-glass opacities and an almost complete opacified left lung. The patient suddenly deteriorated, and death was confirmed 3 h after admission. At autopsy, severe desquamative interstitial pneumonia was diagnosed and was associated with an unusual IgA glomerulonephritis. No SARS-CoV-2 infection was detected in the lung parenchyma by RT- PCR. This is a very unusual case of rapid deterioration of an infant with idiopathic desquamative interstitial pneumonia (IDP) and multiorgan involvement. Based on immunohistochemical stains, we hypothesize that, in IDP, the hyaline membranes arise from necrotizing desquamated pneumocytes. In the COVID-19 era, such cases are extremely difficult to diagnose; they can mimic SARS-CoV-2-induced lung injuries. This pattern of hyaline membrane formation might explain the poor response to oxygen therapy. The present case highlights the importance of autopsy in such challenging cases.

Five simple reasons to discard DIP, or why we should stop calling dolphins big fish

The aim of this review is to explain why the term 'desquamative interstitial pneumonia' (DIP) should be discarded and replaced with modern terminology. Reason 1: DIP is a misnomer. Within a few years after the term was coined, it was shown that the airspace cells in DIP are macrophages not desquamated pneumocytes. Reason 2: As a result of overly simplistic and poorly defined histologic criteria, DIP is currently a mixed bag of smoking-related diseases and unrelated processes in never-smokers. Reason 3: DIP obfuscates the modern concept that smoking causes some forms of parenchymal lung disease. Despite the fact that >80% of cases of DIP are caused by smoking, it is currently classified as a 'smoking-related idiopathic interstitial pneumonia', an oxymoron. Reason 4: The premise that the presence of numerous macrophages within airspaces defines an entity creates problematic histologic overlap with other lung diseases that may feature prominent airspace macrophages. Reason 5: DIP is outdated. It was coined in 1965, when many entities in interstitial lung disease had not been described, smoking-related interstitial lung disease was an unknown concept, computed tomograms of the chest had not been introduced and immunohistochemistry was unavailable. We suggest a way forward, which includes eliminating the term DIP and separating smoking-related lung abnormalities (including accumulation of pigmented airspace macrophages) from cases characterised by numerous non-pigmented macrophages in never-smokers. The laudable goal of smoking cessation is not served well by muddying the relationship between smoking and lung disease with inaccurate, outdated terminology.