Clinicopathological differences between acute and chronic eosinophilic pneumonia

Development of eosinophilic pneumonia from eosinophilic bronchiolitis without asthma: A case report

Eosinophilic bronchiolitis is a disease concept reported in Japan in 2001, that presents with bronchiolitis accompanied by eosinophilia in the blood and lungs. In 2013, hypereosinophilic obliterative bronchiolitis, as a group of disease presenting with eosinophilic bronchiolitis, was proposed in France. The relationship between eosinophilic bronchiolitis and other eosinophil-related diseases has not been clarified. Herein, we report the case of a 56-year-old female patient with eosinophilic bronchiolitis without asthma, which developed into eosinophilic pneumonia. Treatment with oral prednisone improved the respiratory function. According to the clinicopathological findings in this case, eosinophilic bronchiolitis may be a different disease from asthma.

Tips and Tricks in Thoracic Radiology for Beginners: A Findings-Based Approach

This review has the purpose of illustrating schematically and comprehensively the key concepts for the beginner who approaches chest radiology for the first time. The approach to thoracic imaging may be challenging for the beginner due to the wide spectrum of diseases, their overlap, and the complexity of radiological findings. The first step consists of the proper assessment of the basic imaging findings. This review is divided into three main districts (mediastinum, pleura, focal and diffuse diseases of the lung parenchyma): the main findings will be discussed in a clinical scenario. Radiological tips and tricks, and relative clinical background, will be provided to orient the beginner toward the differential diagnoses of the main thoracic diseases.

Eosinophilic Lung Diseases

The eosinophilic lung diseases may manifest as chronic eosinophilic pneumonia, acute eosinophilic pneumonia, or as the Löffler syndrome (generally of parasitic etiology). The diagnosis of eosinophilic pneumonia is made when both characteristic clinical-imaging features and alveolar eosinophilia are present. Peripheral blood eosinophils are generally markedly elevated; however, eosinophilia may be absent at presentation. Lung biopsy is not indicated except in atypical cases after multidisciplinary discussion. The inquiry to possible causes (medications, toxic drugs, exposures, and infections especially parasitic) must be meticulous. Idiopathic acute eosinophilic pneumonia may be misdiagnosed as infectious pneumonia. Extrathoracic manifestations raise the suspicion of a systemic disease especially eosinophilic granulomatosis with polyangiitis. Airflow obstruction is frequent in allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic obliterative bronchiolitis. Corticosteroids are the cornerstone of therapy, but relapses are common. Therapies targeting interleukin 5/interleukin-5 are increasingly used in eosinophilic lung diseases.

Idiopathic chronic eosinophilic pneumonia: a differential diagnosis of lower respiratory tract infection

A 43-year-old woman presented with a presumed lower respiratory tract infection, with symptoms of persistent cough, lethargy, fevers and night sweats. Initial general practitioner assessment revealed raised C reactive protein and a leucocytosis comprising both a neutrophilia and an eosinophilia. The patient was initially treated for bacterial pneumonia. Despite treatment, the patient's condition did not improve and hospital admission was arranged for further investigation. Initial physical examination was unremarkable. A chest X-ray revealed bilateral, symmetrical, peripheral consolidation with an upper zone predominance. Subsequently, endobronchial washings revealed abundant eosinophils. A diagnosis of idiopathic chronic eosinophilic pneumonia was made, and the patient responded well to oral corticosteroids with complete resolution of radiological appearances 1 month later.

Evaluating the relationship between high-resolution computed tomography findings and their extent in eosinophilic lung diseases with peripheral blood eosinophil level

Purpose

Eosinophilic lung diseases are a group of pulmonary disorders associated with peripheral or tissue eosinophilia. They can be classified into primary (idiopathic) and secondary groups based on their aetiology. On the other hand, blood eosinophilia is a common clinical problem with various causes. In many cases the lung infiltrations in patients with peripheral eosinophilia are non-eosinophilic. Herein, we aim to assess the relationship between blood eosinophilia and abnormal high-resolution computed tomography (HRCT) features and their extent in idiopathic chronic eosinophilic pneumonia (ICEP) (the most common form of idiopathic eosinophilic lung disease). This can help in differentiating eosinophilic from non-eosinophilic lung infiltrations in patients with blood eosinophilia.

Material and methods

In this descriptive-correlational study, all patients with proven ICEP, who were referred to Masih Daneshvari Hospital, Tehran, Iran from 2012 to 2019, were included. The ICEP diagnosis was based on lung infiltrations on imaging, in addition to increased numbers of eosinophils in bronchoalveolar lavage fluid, blood or lung biopsy samples, and rapid response to corticosteroids. Patients with known aetiologies for eosinophilic lung diseases were excluded. The HRCT findings and their extent in each patient were compared with the blood eosinophil level.

Results

Positive correlation was found only between blood eosinophil level and frequency and extent of consolidation, and with frequency of lymphadenopathy.

Conclusions

HRCT can help to differentiate eosinophilic from non-eosinophilic lung infiltrations in patients with blood eosinophilia by comparing the extent of consolidation with the blood eosinophil level.

Acute Lung Injury and Non-infectious Pneumonias

Lung injury can occur secondary to a myriad of causes, including infection, immunologic disorders, drug toxicity, or inhalational injury among others. Although the list of causative agents is long, the lung’s response to injury is limited resulting in similar patterns of disease irrespective of the cause. From a pathological perspective, acute lung injury refers to a group of entities that present with acute or subacute disease. These conditions are characterized by particular histological patterns including diffuse alveolar damage, acute fibrinous and organizing pneumonia, organizing pneumonia, and eosinophilic pneumonia and clinically correspond to the varying degrees of acute respiratory distress syndrome (Patel et al, Chest 125:197–202, 2004; Beasley et al, Arch Pathol Lab Med 126:1064–1070, 2002; Avecillas et al, Clin Chest Med 27:549–557, 2006; Cottin, Cordier, Semin Respir Crit Care Med 33:462–475, 2012; Ferguson et al, Intensive Care Med 38:1573–1582, 2012). In most cases, the underlying cause will not be apparent from the histological findings requiring close correlation with clinical history and laboratory findings to determine the etiology. Nevertheless, careful search for infectious organisms with application of histochemical and immunohistochemical stains should be performed in all cases in order to identify cases that benefit from more targeted treatment.

Eosinophilic pneumonia: A review of the previous literature, causes, diagnosis, and management

Eosinophilic pneumonia (EP) is a rare disorder, comprising several heterogeneous diseases. Two major types of EP are acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP), both of which are characterized by marked accumulation of eosinophils in lung tissues and/or BAL fluid. AEP and CEP share some similarities in terms of pathophysiology, radiological findings, and treatment response to corticosteroids. However, they distinctly differ in etiology, clinical manifestations, and the nature of disease course. Especially, although AEP and CEP respond well to corticosteroids, relapse frequently occurs in patients with CEP, but rarely in those with AEP. Although CEP occasionally persists and becomes corticosteroid dependent, most patients with AEP completely recover. This article reviews previous studies and discusses the etiology, clinical manifestations, and treatment of AEP and CEP.

A Woman with Asthma and Peripheral Ground-Glass Opacities

Eosinophilic lung disease is a heterogeneous group of disorders that reveal eosinophil involved lung tissue often in patients with asthma or atopy. Classification and diagnostic criteria of eosinophilic lung disease are not well-established; however, peripheral ground-glass opacity is typical on chest computed tomography. Another etiology of this same radiographic finding reported in the literature is silicone embolism syndrome. Here, we present a 43-year-old female with poorly controlled severe persistent asthma presenting with difficulty breathing. Computed tomography showed peripherally dominant ground-glass opacity. Peripheral blood, bronchoalveolar lavage fluid analysis, and transbronchial biopsy did not find eosinophilia. Serial bronchoalveolar lavage of the demonstrated increasingly blood-tinged fluid. The patient required mechanical ventilation upon admission. After further questioning the patient revealed that she had frequently received injectable cosmetics at non-licensed establishments. Initially, due to past medical history, presentation, and radiographic findings, eosinophilic pneumonia was suspected. However, after a review of the patient's social history and risk factors, silicone embolisms syndrome became a likely diagnosis. The patient had good clinical response to high dose steroid therapy.

Conjunctival Eosinophilic Masses With Chronic Eosinophilic Pneumonia

PURPOSE

To report a case of ocular findings associated with chronic eosinophilic pneumonia (CEP).

CASE

A 63-year-old man was referred to the National Institution of Hospital Organization Tokyo Medical Center with bilateral eyelid swelling due to giant papillomatous changes, each measuring approximately 10 mm in diameter with severe hyperemia on the tarsal conjunctiva. He was followed for CEP for 8 years and systemically treated with 6 mg oral prednisolone for an average of 5 years. Because the lesions did not respond to topical 0.1% tacrolimus and 0.025% levocabastine treatment and because an increase in intraocular pressure was found to occur as a side effect of 0.01% betamethasone instillation for several months, we performed surgical resection of the bilateral conjunctival lesions. Histopathological findings revealed extreme eosinophil, plasma cell, and lymphocytic infiltration and interstitial fibrosis. These conjunctival specimen findings were similar to those seen in the alveolar lesions in CEP. Topical antiinflammatory therapy using 0.1% tacrolimus eye drops was administered after surgery, which relieved the patient's lid swelling and itching. However, the lesions concurrently changed to be consistent with exacerbation and remission of systemic CEP.

CONCLUSIONS

Based on the clinical course and histopathology, the conjunctival proliferative masses in our case were assumed to be associated with CEP.

Drug-induced eosinophilic pneumonia: A review of 196 case reports

BACKGROUND AND OBJECTIVE

Eosinophilic pneumonia (EP) is an important subset of patients who present with pulmonary infiltrates and eosinophilia (PIE). EP is classified by chronicity and etiology and drug-induced EP is the main cause of secondary EP. The primary goal of this review was to examine all the case reports published since the syndrome was defined in 1990. It remains unclear whether acute or chronic EP (AEP or CEP) represent different diseases, and the secondary goal of this review is to determine if there are factors that may help distinguish these 2 entities.

METHODS

PubMed (MEDLINE and Medical Subject Headings) was searched for case reports of drug-induced EP or PIE syndrome published between 1990 and 2017. Case reports were only included if the diagnostic criteria for AEP or CEP were fulfilled. For each case, data were extracted pertaining to age, sex, type of medication associated with the disease, time from the onset of symptoms to diagnosis, eosinophil counts in the blood, eosinophil fractions in bronchoalveolar lavage (BAL) fluid, initial chest radiograph and computed tomography results, use of mechanical ventilation, and use of steroid treatment and recurrence.

RESULTS

We found 196 case reports describing drug-induced EP. The leading cause was daptomycin. From our review, we found that AEP is more common in younger patients with no gender preference. Eosinophilia in the blood at the time of diagnosis characterized only the CEP patients (80% in CEP vs. 20% in AEP). Abnormal findings on radiographic imagine was similar in both syndromes. A significant portion of AEP patients (20%) presented with acute respiratory failure requiring mechanical ventilation. Most patients with EP were treated with steroids with a higher rate of relapse observed in patients with CEP.

CONCLUSION

AEP is a much more fulminant and severe disease than the gradual onset and slowly progressive nature of CEP. The pathogenesis of AEP and CEP remains unclear. However, there is significant clinical overlap among AEP and CEP that are associated with drug toxicity, suggesting the possibility that AEP and CEP are distinct clinical presentations that share a common pathogenic pathway.

Spectrum of Smoking-related Lung Diseases: Imaging Review and Update

There is increased awareness of smoking-related lung diseases other than lung cancer and chronic obstructive pulmonary disease. Concurrently, there is general acceptance that there is difficulty in establishing a specific diagnosis of smoking-related interstitial lung disease (ILD), as many patients may not undergo biopsy to facilitate a specific histopathologic diagnosis. Cases that do proceed to biopsy may demonstrate multiple abnormalities, and histologic overlap between different disease processes may confound the picture. This review outlines the key aspects of smoking-related lung disease, including entities secondary to smoking-related lung inflammation such as respiratory bronchiolitis-ILD, desquamative idiopathic pneumonia, and pulmonary Langerhans cell histiocytosis, as well as chronic fibrosing lung diseases strongly associated with cigarette smoke including idiopathic pulmonary fibrosis, combined pulmonary fibrosis and emphysema, nonspecific interstitial pneumonia, and rheumatoid arthritis-ILD. The focus will be on incorporation of clinical findings, key pulmonary function testing parameters, high-resolution computer tomography (HRCT) findings, and pathologic correlates in refining the differential diagnosis and differentiating between the various entities.

Eosinophilic Lung Diseases

Eosinophilic lung diseases especially comprise eosinophilic pneumonia or as the more transient Löffler syndrome, which is most often due to parasitic infections. The diagnosis of eosinophilic pneumonia is based on characteristic clinical-imaging features and the demonstration of alveolar eosinophilia, defined as at least 25% eosinophils at BAL. Peripheral blood eosinophilia is common but may be absent at presentation in idiopathic acute eosinophilic pneumonia, which may be misdiagnosed as severe infectious pneumonia. All possible causes of eosinophilia, including drug, toxin, fungus related etiologies, must be thoroughly investigated. Extrathoracic manifestations should raise the suspicion of eosinophilic granulomatosis with polyangiitis.

Chronic Eosinophilic Pneumonia with Subpleural Curvilinear Shadow

We report a rare case of chronic eosinophilic pneumonia with subpleural curvilinear shadow. CT scan showed a patchy consolidation in the bilateral upper lungs. In addition, subpleural curvilinear shadow was found in the bilateral upper lungs. A bronchoalveolar lavage obtained from the right middle lobe showed 25 % eosinophils. Although very rare, we should therefore keep in mind that patients, who have patchy consolidation with areas of subpleural curvilinear shadow in the bilateral upper lungs, may have chronic eosinophilic pneumonia.

Elevation of serum surfactant protein-A with exacerbation in canine eosinophilic pneumonia

A 7-year-old female spayed Labrador Retriever was admitted to our hospital, because of cough with sputum. She was diagnosed as having canine eosinophilic pneumonia (CEP) based on blood eosinophilia, bronchial pattern and infiltrative shadow observed on thoracic radiography, bronchiolar obstruction and air-space consolidation predominantly affecting the right caudal lung lobe, as revealed by computed tomography (CT), predominant eosinophils in CT-guided fine needle aspiration and the clinical course. She exhibited a good response to steroid therapy, and the cough disappeared. The serum surfactant protein (SP)-A level increased with the aggravated symptom and decreased markedly with improvement compared with the C-reactive protein level and the number of eosinophils. We propose that serum SP-A level is a good biomarker in CEP.

Bronchial involvement in chronic eosinophilic pneumonia: a case report

Chronic eosinophilic pneumonia (CEP) is an idiopathic chronic condition characterized by alveolar filling with mixed inflammatory infiltrate consisting largely of eosinophils. On CT, it is usually observed as consolidation, often peripheral and patchy in distribution, with upper lobe dominance. Airway involvement in CEP is very rare. We report on a case of bronchial involvement in CEP.

Eosinophilic Pneumonia

Eosinophilic pneumonia may manifest as chronic or transient infiltrates with mild symptoms, chronic idiopathic eosinophilic pneumonia, or the frequently severe acute eosinophilic pneumonia that may be secondary to a variety of causes (drug intake, new onset of tobacco smoking, infection) and that may necessitate mechanical ventilation. When present, blood eosinophilia greater than 1 × 10⁹ eosinophils/L (and preferably greater than 1.5 × 10⁹/L) is of considerable help for suggesting the diagnosis, however it may be absent, as in the early phase of idiopathic acute eosinophilic pneumonia or when patients are already taking corticosteroids. On bronchoalveolar lavage, high eosinophilia (>25 %, and preferably >40 % of differential cell count) is considered diagnostic of eosinophilic pneumonia in a compatible setting, obviating the need of video-assisted thoracic surgical lung biopsy, which is now performed only on very rare occasions with inconsistency between clinical, biological, and imaging features. Inquiry as to drug intake must be meticulous (www.pneumotox.com) and any suspected drug should be withdrawn. Laboratory investigations for parasitic causes must take into account the travel history or residence and the epidemiology of parasites. In patients with associated extrathoracic manifestations, the diagnosis of eosinophilic granulomatosis with polyangiitis or of the hypereosinophilic syndromes should be raised. Presence of airflow obstruction can be found in hypereosinophilic asthma, allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, or in the recently identified syndrome of hyperosinophilic obliterative bronchiolitis. Corticosteroids remain the cornerstone of symptomatic treatment for eosinophilic pneumonias, with a generally dramatic response. Relapses are common when tapering the doses or after stopping treatment especially in idiopathic chronic eosinophilic pneumonia. Cyclophosphamide is necessary only in patients with eosinophilic granulomatosis with polyangiitis and poor-prognostic factors. Imatinib is very effective in the treatment of the myeloproliferative variant of hypereosinophilic syndromes. Anti-interleukin-5 monoclonal antibodies are promising in the spectrum of eosinophilic disorders.

Chronic Eosinophilic Pneumonia: A Pediatric Case with Idiopathic Bronchiectasis

Chronic eosinophilic pneumonia (CEP) is a rare lung disease and is especially uncommon in children. It presents with subacute respiratory symptoms of hypoxemia and dyspnea, peripheral infiltrates on imaging, and eosinophilia. However, it can be difficult to diagnose, as there is no strict diagnosis criteria and the clinical findings may be very nonspecific. In this case report, we describe a 14-year-old female with an unusual presentation of asymptomatic bronchiectasis, and the role of surgical lung biopsy in the diagnosis of CEP when no peripheral or alveolar eosinophilia is seen. It suggests that perhaps bronchiectasis can also be an unusual presenting sign of CEP and that there may be more asymptomatic cases of CEP with the true incidence being underreported, especially in the pediatric population.

Clinical significance of interleukin 33 (IL-33) in patients with eosinophilic pneumonia

BACKGROUND

Interleukin 33 (IL-33) works as a functional mediator in allergic disease by enhancing the activity of eosinophils and inducing expression of T helper 2 (Th2)-associated cytokines. However, the role of IL-33 in pulmonary eosinophilia has not been elucidated. We investigated the levels of IL-33 in eosinophilic pneumonia (EP) together with associated cytokines, and discussed the clinical significance of IL-33 in EP.

METHODS

Sera and bronchoalveolar lavage fluid (BALF) were obtained from 16 patients with EP, including acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP). Twelve patients with acute respiratory distress syndrome (ARDS) were also included for comparison. The concentration of IL-33 and Th2 cytokines (IL-4, IL-5, IL-13) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The concentration of serum IL-33 was significantly higher in patients with AEP than in CEP. In CEP, only patients with atopic factors showed mild increase of serum IL-33. The concentration of BALF IL-33 was also significantly elevated in AEP, however, it remained quite low in CEP. Among Th2 cytokines, IL-5 was significantly increased in both serum and BALF in AEP, and the level of IL-5 was positively correlated with that of IL-33. ARDS showed no increase of serum and BALF IL-33.

CONCLUSIONS

The remarkable increase of BALF IL-33 in AEP indicated the local production of IL-33 in lungs. IL-33 is considered to be a local key molecule for triggering pulmonary eosinophilia, together with IL-5. BALF IL-33 appears to be a useful marker for discriminating AEP from CEP and ARDS.

Idiopathic acute eosinophilic pneumonia in a 14-month-old girl

Idiopathic acute eosinophilic pneumonia (IAEP), characterized by acute febrile respiratory failure associated with diffuse radiographic infiltrates and pulmonary eosinophilia, is rarely reported in children. Diagnosis is based on an association of characteristic features including acute respiratory failure with fever, bilateral infiltrates on the chest X-ray, severe hypoxemia and bronchoalveolar lavage fluid >25% eosinophils or a predominant eosinophilic infiltrate in lung biopsies in the absence of any identifiable etiology. We present a 14-month-old girl who was admitted to our pediatric intensive care unit because of acute respiratory distress. She had a fever, dry cough, and progressive dyspnea for 1 day. Chest X-ray showed multifocal consolidations, increased interstitial markings, parenchymal emphysema and pneumothorax. IAEP was confirmed by marked pulmonary infiltrates of eosinophils in the lung biopsy specimen. Most known causes of acute eosinophilic pneumonia, such as exposure to causative drugs, toxins, second-hand smoking and infections were excluded. Her symptoms were resolved quickly after corticosteroid therapy.

Eosinophilic pneumonias

This review starts with discussions of several infectious causes of eosinophilic pneumonia, which are almost exclusively parasitic in nature. Pulmonary infections due specifically to Ascaris, hookworms, Strongyloides, Paragonimus, filariasis, and Toxocara are considered in detail. The discussion then moves to noninfectious causes of eosinophilic pulmonary infiltration, including allergic sensitization to Aspergillus, acute and chronic eosinophilic pneumonias, Churg-Strauss syndrome, hypereosinophilic syndromes, and pulmonary eosinophilia due to exposure to specific medications or toxins.

Osteopontin levels are elevated in patients with eosinophilic pneumonia

BACKGROUND AND OBJECTIVE

Osteopontin is a key cytokine involved in pro-inflammatory T helper type 1 (Th1)-associated immune responses, which has recently been implicated in allergic diseases. We investigated the pathogenic role of osteopontin in eosinophilic pneumonia.

METHODS

The concentrations of osteopontin and Th1- or Th2-associated cytokines were measured in BAL fluid (BALF) from 41 patients with eosinophilic pneumonia, including those with acute (AEP, n = 12), chronic (CEP, n = 16), or drug-induced eosinophilic pneumonia (DEP, n = 13). The results were compared with those from patients with other interstitial lung diseases. Immunocytochemistry and double immunofluorescence labelling were performed to determine the cellular source of osteopontin.

RESULTS

Osteopontin was significantly elevated in BALF from patients with eosinophilic pneumonia as compared with BALF from patients with drug-induced interstitial pneumonia, hypersensitivity pneumonitis, idiopathic interstitial pneumonia, or sarcoidosis, and also compared with BALF from healthy volunteers. Osteopontin concentrations elevated at the time of exacerbation decreased during clinical improvement, either spontaneously or as a result of corticosteroid therapy. Elevated concentrations of CXCL10, CCL17 and IL-10 were also detected in BALF from patients with eosinophilic pneumonia. Osteopontin concentrations in BALF of AEP patients were correlated with IL-5, as well as IL-10, CCL11, CCL17 and CXCL10 concentrations. In AEP and DEP patients, serum osteopontin concentrations were also elevated. Double immunofluorescence labelling showed that in patients with eosinophilic pneumonia, osteopontin was expressed in lung eosinophils.

CONCLUSIONS

Osteopontin is likely to contribute to the development of inflammation in patients with eosinophilic pneumonia.

Increased serum ADAM8 concentration in patients with drug-induced eosinophilic pneumonia-ADAM8 expression depends on a the allergen route of entry

BACKGROUND

ADAM8 (a disintegrin and a metalloprotease 8) has been linked to asthma and eosinophilic pneumonia (EP). ADAM8 cleaves a variety of substrates and is a sheddase for CD23, the low affinity IgE receptor. The concentration of soluble ADAM8 (sADAM8) is increased in bronchoalveolar lavage fluid (BALF) from patients with smoking-induced acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP), but not drug-induced EP (Drug-EP). In AEP, the BALF sADAM8 concentration significantly correlates with the soluble CD23 concentration (sCD23).

METHODS

To evaluate the involvement of ADAM8 in the pathogenesis of eosinophilic pneumonia, we measured the concentrations of sADAM8 and its substrate, soluble CD23 (sCD23), in serum from patients with AEP, CEP, and Drug-EP. We also measured the change in the sADAM8 concentration after a provocation test.

RESULTS

In contrast to the BALF findings, serum sADAM8 concentrations were increased in Drug-EP (mean+/-SEM; 639.6+/-49.15) and serum ADAM8 levels correlated positively with the serum sCD23 levels in patients with Drug-EP (P=0.0080, R(2)=0.8465). Serum sADAM8 concentrations were also increased in AEP (409+/-76.91) and CEP (644.7+/-87.03). Serum ADAM8 concentrations were also elevated after the provocation test.

CONCLUSION

Serum ADAM8 concentrations were elevated in Drug-EP, although the sADAM8 concentrations were not increased in the BALF in Drug-EP. Thus, the pathogenesis of AEP and Drug-EP may be distinct with regard to allergen exposure; AEP may be caused by the inhalation of antigens, whereas Drug-EP may be caused by bloodstream antigens. These findings indicate that ADAM8 levels reflect the route of eosinophilic inflammation in EP.

[Idiopathic chronic eosinophilic pneumonia - a diagnostic challenge]

CASE REPORT

A 43-year-old woman with clinical signs of a febrile respiratory infection with cough and dyspnea despite several antecedent antibiotic treatments was admitted to hospital because of persistent bilateral pulmonary infiltrates.

DIAGNOSIS, THERAPY, AND COURSE

In the diagnostic work-up, the most striking laboratory abnormality was an eosinophilia of 31% within the differential blood count. Specimen obtained from bronchoalveolar lavage showed an abnormally high level of eosinophils as well. In the absence of other known causes of an eosinophilic pulmonary disease the diagnosis of idiopathic chronic eosinophilic pneumonia was made. After initiation of corticosteroid medication the abnormal laboratory results, the clinical signs, and the radiologic findings almost completely normalized within 1 week.

CONCLUSION

If an apparent pneumonia fails to respond to conventional antibiotic treatment, a blood eosinophil count should be obtained. If blood eosinophils are abnormally high, diagnosis of idiopathic acute or chronic eosinophilic pneumonia should be considered and confirmed by demonstrating an excess of eosinophils in bronchoalveolar lavage fluid. Due to prognostic and therapeutic consequences idiopathic acute and chronic eosinophilic pneumonia should be distinguished from one another. A rapid response to glucocorticoid therapy supports the diagnosis. In order to avoid relapses, patients with chronic eosinophilic pneumonia have to complete a 6-month treatment.

Transbronchial biopsy is clinically useful in classifying patients with interstitial pneumonia associated with polymyositis and dermatomyositis

BACKGROUND AND OBJECTIVE

The histological type of intraluminal fibrosis is an important prognostic factor for interstitial pneumonia. We therefore examined whether transbronchial lung biopsy (TBLB) specimens are useful for predicting the clinical course and prognosis of patients with interstitial pneumonia associated with polymyositis and dermatomyositis (PM/DM), with particular attention to the different types of intraluminal fibrosis.

METHODS

Twenty-five cases of interstitial pneumonia associated with PM/DM were classified according to the pattern of intraluminal fibrosis as assessed by TBLB, and the clinical course and response to treatment were compared. Interstitial fibrosis was evaluated by sequential thin-section CT scans.

RESULTS

In 19 of 25 (76%) cases, there was sufficient intraluminal fibrosis to perform an evaluation. Intraluminal fibrosis was classified as bud (polyp) type or mural incorporation type (either alone or mixed with bud type). The bud type was seen in five cases and these improved following treatment with corticosteroids only. The mural incorporation type was seen in 14 cases. In 11 of these 14 cases, progressive long-term fibrosis developed and four cases were fatal, in spite of corticosteroid and immunosuppressive therapy. The response to drugs (P < 0.01) and survival (P < 0.05) were significantly greater in patients with bud-type than mural incorporation-type intraluminal fibrosis.

CONCLUSIONS

Classification of the pattern of intraluminal fibrosis as assessed by TBLB is useful for predicting the response to treatment, clinical course and prognosis of interstitial pneumonia associated with PM/DM.

Reduced IgG levels found during acute eosinophilic pneumonia, which normalize during recovery from disease

Clinically there are several different types of eosinophilic pneumonia (EP), but other than for tropical pulmonary eosinophilia, the humoral immune response between different types of EP, such as acute eosinophilic pneumonia (AEP), chronic EP, drug-induced EP, allergic bronchopulmonary aspergillosis, and Churg-Strauss syndrome, has not been examined. Immunoglobulin G (IgG) and E (IgE) serum concentrations were analyzed in patients with EP, or bacterial pneumonia, and in age-matched controls. Patients with AEP had lower IgG levels than the age-matched controls. Serum IgG levels in patients with AEP were significantly lower than in patients with other types EP or bacterial pneumonia. IgG2 and IgG4 were also significantly decreased in AEP, compared to age-matched controls. In AEP, the serum IgG levels were significantly decreased during active disease and increased during remission, but the serum IgE levels did not change significantly, indicating a decrease in serum IgG is a common feature of AEP. Low IgG levels were significantly correlated with serum surfactant protein D and absolute eosinophil counts in the bronchoalveolar lavage fluid of patients with AEP. This is the first reported study of immunoglobulin levels in AEP. The pathogenesis of AEP might negatively affect serum IgG levels, but not IgE levels. The present findings might indicate that serum IgG reflects the inflammatory response in AEP.

Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview

Eosinophilic lung diseases are a diverse group of pulmonary disorders associated with peripheral or tissue eosinophilia. They are classified as eosinophilic lung diseases of unknown cause (simple pulmonary eosinophilia [SPE], acute eosinophilic pneumonia [AEP], chronic eosinophilic pneumonia [CEP], idiopathic hypereosinophilic syndrome [IHS]), eosinophilic lung diseases of known cause (allergic bronchopulmonary aspergillosis [ABPA], bronchocentric granulomatosis [BG], parasitic infections, drug reactions), and eosinophilic vasculitis (allergic angiitis, granulomatosis [Churg-Strauss syndrome]). The percentages of eosinophils in peripheral blood and bronchoalveolar lavage fluid are essential parts of the evaluation. Chest computed tomography (CT) demonstrates a more characteristic pattern and distribution of parenchymal opacities than does conventional chest radiography. At CT, SPE and IHS are characterized by single or multiple nodules with a surrounding ground-glass-opacity halo, AEP mimics radiologically hydrostatic pulmonary edema, and CEP is characterized by nonsegmental airspace consolidations with peripheral predominance. ABPA manifests with bilateral central bronchiectasis with or without mucoid impaction. The CT manifestations of BG are nonspecific and consist of a focal mass or lobar consolidation with atelectasis. The most common CT findings in Churg-Strauss syndrome include sub-pleural consolidation with lobular distribution, centrilobular nodules, bronchial wall thickening, and interlobular septal thickening. The integration of clinical, radiologic, and pathologic findings facilitates the initial and differential diagnoses of various eosinophilic lung diseases.

Elevated soluble ADAM8 in bronchoalveolar lavage fluid in patients with eosinophilic pneumonia

BACKGROUND

ADAM (a disintegrin and metalloprotease) family members, characterized by a metalloprotease and a disintegrin domain, are membrane-anchored glycoproteins involved in proteolysis and cell adhesion. ADAM8 might have an important role in allergic inflammation. It can cleave a variety of substrates and is a sheddase for VCAM-1 and CD23, the low-affinity IgE receptors.

METHODS

To evaluate the contribution of ADAM8 to the pathogenesis of eosinophilic pneumonia (EP), we measured the concentrations of soluble ADAM8 (sADAM8) and its substrates, soluble VCAM-1 (sVCAM-1) and soluble CD23 (sCD23), in bronchoalveolar lavage fluid from patients with smoking-induced acute eosinophilic pneumonia (AEP), chronic idiopathic eosinophilic pneumonia (CEP), and drug-induced eosinophilic pneumonia (drug-EP).

RESULTS

The sADAM8 and sVCAM-1 concentrations were increased in AEP and CEP. The sCD23 concentration was elevated in AEP. In AEP, but not CEP, the sADAM8 concentration significantly correlated with those of both sVCAM and sCD23.

CONCLUSION

The pathogenesis of AEP, CEP, and drug-EP was distinct with regard to ADAM8. Our results are the first to associate ADAM8 with eosinophilic responses and lung inflammation in humans.

Correlation between rheumatoid factor and peripheral eosinophil count in chronic eosinophilic pneumonia

The relationship between the blood level of rheumatoid factor (RF) and the peripheral blood eosinophil (Eo) count (white blood cellsx%Eo, Eo count) in a patient diagnosed with chronic eosinophilic pneumonia was evaluated from before the onset till resolution of the disease. RF levels correlated with Eo counts, and showed a strong correlation with the logarithmic value of the Eo counts (r=0.816). RF levels tended to become elevated earlier and decline later than Eo counts or abnormal X-ray shadows. We concluded that the RF level may reflect the activity of this disease. The mechanism of RF elevation in eosinophil-activated disorders needs to be clarified.