Anti-immunoglobulin E treatment with omalizumab in allergic diseases: an update on anti-inflammatory activity and clinical efficacy

Omalizumab is a humanized monoclonal anti-IgE antibody developed for the treatment of allergic disease, with established efficacy in patients with moderate-to-severe allergic asthma and in patients with intermittent (seasonal) and persistent (perennial) allergic rhinitis (AR). Omalizumab is known to result in a marked reduction in serum levels of free IgE and down-regulation of IgE receptors on circulating basophils. Recent work has shed further light on its mechanism of action, showing significant and profound reductions in tissue (nasal and bronchial) eosinophils and in bronchial IgE+ cells (mast cells), as well as T cells and B cells. Omalizumab treatment was also shown to be associated with down-regulation of IgE receptors on circulating (precursor) dendritic cells, suggesting that blocking IgE may inhibit more chronic aspects of allergic inflammation involving T cell activation. Further work with omalizumab demonstrated it to have important benefits in patients with poorly controlled asthma despite high-dose inhaled corticosteroid therapy, and analysis of clinical data suggests that the patients who are the best 'responders' to anti-IgE treatment are those with asthma at the more severe end of the spectrum. Notably, systemic anti-IgE therapy with omalizumab has been shown to improve symptoms, quality of life and disease control (asthma exacerbations) in patients with concomitant asthma and persistent AR. These impressive clinical data and the studies elucidating the anti-inflammatory profile of omalizumab also serve to emphasize the fundamental importance of IgE in the pathogenesis of allergic diseases.     

Airway inflammation and eotaxin in exhaled breath condensate of patients with severe persistent allergic asthma during omalizumab therapy

PurposeThe central role of IgE in allergic inflammation in asthma has provided a rationale for the development of omalizumab, the humanized monoclonal anti-IgE antibody. The aim of the study was to determine the effect of omalizumab treatment on changes in airway inflammatory process and eotaxin in exhaled breath condensate in patients with persistent severe allergic asthma.Material and MethodsThe study was performed on a group of 19 patients with severe persistent allergic asthma treated with conventional therapy (according to GINA 2006) and with or without omalizumab (9 vs 10 patients). Eotaxin in exhaled breath condensate, exhaled nitric oxide, blood eosinophil count and serum ECP were measured before and after 16 weeks of therapy.ResultsIn the group treated with omalizumab, a statistically significant decrease in the concentrations of eotaxin in EBC, FENO, serum ECP, and blood eosinophil count after 16 weeks of treatment was observed. Statistically significant correlations were revealed between the decrease in eotaxin and the decrease in FENO, serum ECP and blood eosinophil count after omalizumab therapy.ConclusionsDownregulation of eotaxin expression in the airways through limitation of eosinophilic inflammation could be essential in the beneficial effect of anti-IgE therapy with omalizumab in asthma patients.     

Anti-IgE therapy in asthma: rationale and therapeutic potential

Airway inflammation is found in virtually all individuals with asthma symptoms. The factors contributing to asthma-related airway inflammation are multiple and involve a number of different inflammatory cells and mediators. Allergic responses at the level of the respiratory system are mostly mediated by IgE-dependent mechanisms. After sensitization of a susceptible individual and the synthesis and binding of allergen-specific IgE to target cells, atopic individuals respond immunologically to common, naturally occurring allergens by releasing mast cell-derived mediators. Subsequent allergen exposure in susceptible individuals produces a characteristic cascade of events orchestrated by immune effector cells, most prominently, mast cells, T lymphocytes and eosinophils. A new strategy, neutralizing IgE antibodies, inhibits expression of allergic symptoms by preventing the initial trigger of the allergic reaction, IgE binding to IgE-receptor bearing cells. rhuMAb-E25 is a recombinant humanized monoclonal anti-IgE antibody currently under investigation that has been shown to reduce allergic responses in atopic individuals and to improve symptoms and reduce rescue medication and corticosteroid use in patients with allergic asthma. Thus, the clinical effectiveness of rhuMAb-E25 supports the central role of IgE in allergic reactions and the viability of anti-IgE therapy as a potentially effective treatment option for asthma.     

Churg-Strauss综合征的肺部病理形态学观察

目的 探讨Churg-Strauss综合征的临床及肺部病理特点.方法 收集3例Churg-Strauss综合征患者的临床资料并进行分析,对3例肺组织(包括1例尸检和2例开胸肺活检标本)行4%甲醛固定,常规石蜡切片,HE染色,观察病理改变.结果 2例男性,1例女性;年龄分别为68、58、12岁;3例均有反复哮喘,2例有外周血嗜酸性粒细胞计数升高,胸部CT示肺部有多发实变影,临床上有诊断Churg-Strauss综合征的线索.1例因累及心脏导致嗜酸性粒细胞浸润性心肌炎及血管炎,并发心肌梗死而死亡.显微镜下,3例均可见血管炎、血管周的过敏性肉芽肿、嗜酸性粒细胞肺炎和哮喘性支气管炎表现.结论 应对Churg-Strauss综合征有充分的认识,对有相关症状的患者,应复查CT;一些病例临床体征虽不典型,但肺部有典型的病理改变,必要时需进行肺部活检.     

The methodological aspects of nasal and exhaled nitric oxide levels in adult Japanese asthmatics

Background: Because both allergic rhinitis and asthma are caused by eosinophilic airway inflammation, using the same method to measure the eosinophilic inflammation of both the upper and lower airway would be advantageous. The levels of nitric oxide in exhaled air (FeNO) and nasal air (nNO) are useful as noninvasive markers of eosinophilic airway inflammation. Although the off-line method of measuring these parameters is easier and more useful than the on-line method, studies using the off-line method are rare in Japan. Methods: In Study 1, we measured the levels of nNO and FeNO in 9 healthy controls and 9 subjects with allergic rhinitis, to validate the methodology for using the off-line method to measure nNO. In Study 2, we measured the nNO and FeNO levels of and performed spirometry on 69 stable asthmatics treated with inhaled corticosteroid. Results: In Study 1, nNO levels were significantly increased in patients with allergic rhinitis compared with healthy subjects (31.0 [20.8 to 41.2] versus 7.4 [0.0 to 14.8] ppb {median [95% confidence interval]}, p=0.018). The 69 patients with asthma that comprised the study population in Study 2 were classified as asthmatics with rhinitis (treatment-na?ve, n=14; treated with antiallergic drugs, n=11; treated with intranasal corticosteroid, n=19) and asthmatics without rhinitis (n=15). Although FeNO did not differ among groups, nNO was significantly increased in treatment-na?ve asthmatics with rhinitis compared with patients with asthma only (26.5 [17.1 to 35.9] versus 8.0 [-1.1 to 17.1] ppb, p=0.033). Conclusion: nNO levels measured by the off-line method are useful markers of allergic rhinitis.     

Double-blind trials of azelastine nasal spray monotherapy versus combination therapy with loratadine tablets and beclomethasone nasal spray in patients with seasonal allergic rhinitis. Rhinitis Study Groups.

BACKGROUND: Azelastine hydrochloride is an H1-receptor antagonist with antiinflammatory properties that is available in the US as Astelin Nasal Spray for the treatment of seasonal allergic rhinitis. The symptoms of seasonal allergic rhinitis can initially be treated with monotherapy using either an antihistamine or an intranasal corticosteroid. Patients whose symptoms do not respond adequately are often prescribed a combination of both an antihistamine and an intranasal corticosteroid. OBJECTIVE: Three multicenter, randomized, double-blind studies were conducted to determine whether patients with moderate-to-severe symptoms of seasonal allergic rhinitis who had responded inadequately to monotherapy with either an oral antihistamine or an intranasal corticosteroid, and who were candidates for combination therapy with both an oral antihistamine and an intranasal corticosteroid, could be effectively treated with azelastine nasal spray monotherapy. METHODS: Following a 1- to 2-week washout period, patients were randomized to 7 days of double-blind treatment with either azelastine nasal spray (2 sprays per nostril bid, 1.1 mg/day) monotherapy or combination therapy with oral loratadine (Claritin, one 10-mg tablet/day) plus intranasal beclomethasone dipropionate monohydrate (Beconase AQ, 2 sprays per nostril bid, 336 microg/day). Efficacy was determined at the end of the study by both a physician assessment of the need for additional anti-rhinitis medication and a patient global evaluation of therapeutic effectiveness. The three studies were conducted at 71 investigational sites during the 1998 spring allergy season. Three separate studies were conducted to verify the reproducibility of the new study design. RESULTS: In all three studies a total of 1,070 patients were randomized to double-blind treatment. There were no statistically significant differences in the percentage of patients treated with azelastine nasal spray versus patients treated with a combination of loratadine tablets and beclomethasone nasal spray who did not require additional anti-rhinitis medication (32% to 45% and 39% to 46%, respectively). The patient global evaluation indicated that 77% to 84% of the patients treated with azelastine nasal spray had symptomatic improvement and 85% to 90% of the patients treated with loratadine tablets and beclomethasone nasal spray had symptomatic improvement. The most commonly reported adverse experience with azelastine nasal spray was a transient aftertaste (8%), while the most commonly reported adverse experience with loratadine tablets and beclomethasone nasal spray in combination was headache (6%). CONCLUSIONS: Based on the percentage of patients not requiring additional antirhinitis medication and the patient assessment of efficacy, azelastine nasal spray monotherapy was as effective as the combination of oral loratadine plus intranasal beclomethasone in treating moderate-to-severe symptoms of seasonal allergic rhinitis.     

Surface plasmon resonance analysis of free IgE in allergic patients receiving omalizumab (Xolair)

The diagnosis of human allergic disease involves an initial clinical history based association of allergic symptoms with an allergen exposure. This is followed by confirmation of sensitization (IgE antibody positivity) with skin test, serology or provocation testing. Once diagnosed, the allergic individual can be managed using one or several modalities that involve allergen avoidance, pharmacotherapy, allergen immunotherapy and anti-IgE therapy. This report examines Law of Mass Action considerations for the design of immunological methods which permit the quantification of free (non-Omalizumab bound) IgE in the serum of patients receiving anti-IgE therapy. The rationale for and design and performance of a surface plasmon resonance assay for the detection of "free" IgE (unbound with anti-IgE) is presented as an alternative to microtiter plate based ELISAs.     

Eotaxin in induced sputum of asthmatics: relationship with eosinophils and eosinophil cationic protein in sputum

BACKGROUND: Eosinophilic inflammation is a crucial aspect of allergic diseases such as bronchial asthma. An eosinophil-active chemokine, eotaxin, may play a role in the pathogenesis of the tissue eosinophilia accompanying asthma. METHODS: Induced sputa were obtained from 53 patients with atopic asthma and six healthy subjects, and the concentration of eotaxin in the sputum was measured by ELISA. We investigated whether the sputum content of eotaxin is related to 1) asthma status or corticosteroid therapy, and 2) other sputum indices, including percentage of eosinophils and concentration of eosinophil cationic protein (ECP). RESULTS: The patients with stable or unstable asthma showed significantly higher concentrations of sputum eotaxin than the normal controls. The level of sputum eotaxin demonstrated a positive correlation with the percentage of eosinophils in stable asthmatics not receiving corticosteroid therapy, but not in stable patients treated with corticosteroids, or in unstable patients. Sputum eotaxin demonstrated a positive correlation with ECP in asthmatic patients who were either in a stable state or not receiving steroid therapy. CONCLUSIONS: The elevated level of eotaxin detected in association with increased eosinophils and ECP in the sputum of asthmatics suggests that eotaxin is involved in the pathogenesis of eosinophilic airway inflammation. The relationship of eotaxin to airway eosinophilia may be modified by the stability status of asthma and corticosteroid therapy.     

Monoclonal anti-IgE antibody: a novel therapy for allergic airways disease.

LEARNING OBJECTIVES: To familiarize the practitioner with a novel (monoclonal anti-immunoglobulin [Ig]E antibody) form of therapy for allergic airways disease. To understand the relevance of IgE as a therapeutic target. To appreciate the concepts behind the design of the molecule. To learn how anti-IgE was used in clinical trials. To anticipate the likely effects (efficacy and safety) in clinical use in patients with allergic asthma and with allergic rhinitis. To characterize the types of patients who might benefit from this therapy. DATA SOURCES: Published data for preclinical and clinical studies. RESULTS: Omalizumab is a nonimmunogenic, nonanaphylactogenic monoclonal anti-IgE antibody. In clinical use, omalizumab reduces levels of serum-free IgE. Given subcutaneously in patients with moderate-severe allergic asthma, omalizumab reduced exacerbations compared with placebo, and at the same time it allowed inhaled corticosteroids to be reduced or withdrawn. In patients with allergic rhinitis, omalizumab reduced the severity of symptoms and rescue antihistamine usage versus placebo. In both settings, quality of life was improved with active treatment relative to placebo. The drug seems safe and well tolerated. CONCLUSION: As the first clinical anti-IgE agent, omalizumab is an interesting new addition to the currently available therapies for allergic airways disease. The benefits demonstrated underline the importance of IgE in these conditions. The use of anti-IgE in other IgE-mediated allergic diseases warrants further research.     

Anti-IgE efficacy in murine asthma models is dependent on the method of allergen sensitization

BACKGROUND: Murine models used to delineate mechanisms and key mediators of asthma have yielded conflicting results and suggest that the dominant mechanism and mediators required for disease induction differ depending on the model and method of allergen sensitization used. OBJECTIVE: The goal of this study was to determine whether the mode of allergen sensitization influenced the role that IgE had in allergen-induced pulmonary eosinophilic inflammation. METHODS: Mice were exposed to dust mite extract in 2 models of allergic inflammation that differed in the method of sensitization. We compared sensitization by aerosol exposure with and without concomitant human respiratory syncytial virus infection with sensitization by means of systemic (intraperitoneal) exposure with adjuvant. After sensitization, animals were similarly challenged with aerosolized allergen. Animals were treated with anti-IgE mAb to deplete IgE and to determine its role in the induction of allergic inflammation and mucosa pathology in these models. RESULTS: Concomitant respiratory syncytial virus infection significantly enhanced allergen sensitization by aerosol exposure and exacerbated eosinophilic inflammation and airway mucosa pathology. Depletion of IgE in this model significantly reduced lung eosinophilic inflammation and airway mucosa pathology. However, in the model in which animals were sensitized by means of systemic allergen exposure with adjuvant, depletion of IgE had no ameliorative effect on lung inflammation or pathology. CONCLUSION: We demonstrated that the method of antigen sensitization can delineate the role of IgE in allergen-induced lung inflammation. In a murine model that more closely resembles ambient allergen exposure in human subjects, IgE had a critical role in the pathogenesis of allergic asthma and mucosa pathology. The results parallel the results reported with anti-IgE efficacy in allergic asthmatic human subjects.     

Induced sputum: comparison of postinfectious cough with allergic asthma in children

BACKGROUND: Cough persisting after a respiratory infection is common in children and is often managed as asthma. However, little is known about the pathophysiologic mechanisms of such cough and how it compares with asthma. OBJECTIVE: We used the technique of induced sputum to examine the inflammatory index values associated with persistent cough or allergic asthma in children. We hypothesized that the sputum from children with persistent postinfectious cough would differ from that of children with allergic asthma in that the former would lack eosinophils compared with the latter.Study design: Sputum production was induced with hypertonic saline solution in 34 children: 12 with cough persisting for 1 month or more after an apparent respiratory tract infection, not treated with corticosteroid; 11 with untreated atopic asthma, not using inhaled corticosteroid; and 11 with treated atopic asthma using inhaled corticosteroid. RESULTS: The percentage of eosinophils in the sputum of children with cough was significantly lower than in the sputum of children with untreated allergic asthma (median 0.5% vs 14.5%, P <.0001). Similarly, the percentage of eosinophils in the sputum of children with asthma treated with inhaled steroids was significantly lower compared with untreated asthmatic children (1.5% vs 14.5%, P <.0001). The peripheral blood eosinophils, serum eosinophil cationic protein, and nasal percent eosinophils of the patients with cough were also significantly lower than those from patients with untreated asthma. Methacholine challenge in 6 of the 11 cough patients tested showed mild-to-moderate hyperresponsiveness, whereas the other 5 had a negative methacholine challenge. CONCLUSIONS: Children with persistent postinfectious cough do not have airway eosinophilia typical of untreated asthma. Despite the absence of eosinophilic inflammation, some of the patients with chronic cough had reactive airways. These results suggest that postinfectious cough in children has different pathophysiologic features than allergic asthma and probably represents a different disease.     

Detection of IL-5 and IL-1 receptor antagonist in bronchoalveolar lavage fluid in acute eosinophilic pneumonia

BACKGROUND: Acute eosinophilic pneumonia is an idiopathic cause of respiratory failure, characterized by very high numbers of alveolar eosinophils without significant blood eosinophilia. OBJECTIVE: The purpose of this study was to determine which cytokines are associated with acute eosinophilic pneumonia. METHODS: Soluble IL-1 type II receptor and the cytokines IL-1β, IL-1ra, IL-3, IL-5, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-α were measured in serum and in bronchoalveolar lavage fluid from two patients with acute eosinophilic pneumonia during both acute and convalescent phases. RESULTS: Compared with patients with adult respiratory distress syndrome, the patients with acute eosinophilic pneumonia had high bronchoalveolar lavage fluid levels of IL-5, IL-1ra, and soluble type II IL-1 receptor but not IL-1β, tumor necrosis factor-α>, IL-3, or granulocyte-macrophage colony-stimulating factor. Bronchoalveolar lavage fluid levels of IL-5 and IL-1ra fell after resolution of symptoms. In the serum of patients with acute eosinophilic pneumonia, IL-5 was not detectable, and IL-1ra was initially high but fell after corticosteroid treatment. CONCLUSION: Acute eosinophilic pneumonia is characterized by locally high levels of IL-5, IL-1ra, and soluble type II IL-1 receptor in the alveolar space. (J ALLERGY CLIN IMMUNOL 1996;97:1366-74.)     

Anti-IgE therapy

IgE has a central role in the initiation of allergic hypersensitivity reactions. Pioneered by the development of humanized monoclonal antibodies directed against IgE, anti-IgE therapy represents an original approach to the treatment of allergic disease and has demonstrated promise in preventing the symptoms of asthma, allergic rhinitis, and food allergy. The primary mechanism of action of anti-IgE therapy is the reduction in serum levels of IgE and FcepsilonRI expression on mast cells and basophils.     

Efficacy and safety of a recombinant anti-immunoglobulin E antibody (omalizumab) in severe allergic asthma

BACKGROUND: Patients with severe asthma are often inadequately controlled on existing anti-asthma therapy, constituting an unmet clinical need. OBJECTIVE: This randomized, double-blind, placebo-controlled trial evaluated the ability of omalizumab, a humanized monoclonal anti-IgE antibody, to improve disease control sufficiently to enable inhaled corticosteroid reduction in patients with severe allergic asthma. METHODS: After a run-in period when an optimized fluticasone dose (> or =1000 microg/day) was received for 4 weeks, patients were randomized to receive subcutaneous omalizumab [minimum 0.016 mg/kg/IgE (IU/mL) per 4 weeks; n=126] or matching placebo (n=120) at intervals of 2 or 4 weeks. The study comprised a 16-week add-on phase of treatment followed by a 16-week fluticasone-reduction phase. Short-/long-acting beta(2)-agonists were allowed as needed. RESULTS: Median reductions in fluticasone dose were significantly greater with omalizumab than placebo: 60% vs. 50% (P=0.003). Some 73.8% and 50.8% of patients, respectively, achieved a > or =50% dose reduction (P=0.001). Fluticasone dose reduction to < or =500 microg/day occurred in 60.3% of omalizumab recipients vs. 45.8% of placebo-treated patients (P=0.026). Through both phases, omalizumab reduced rescue medication requirements, improved asthma symptoms and asthma-related quality of life compared to placebo. CONCLUSION: Omalizumab treatment improves asthma control in severely allergic asthmatics, reducing inhaled corticosteroid requirements without worsening of symptom control or increase in rescue medication use.     

IgE and non-IgE-mediated food allergy: treatment in 2007

PURPOSE OF REVIEW: Our understanding of the mechanism of food allergy has substantially increased over the past decade. Food allergies can be classified into those that are IgE mediated and those that are non-IgE mediated. RECENT FINDINGS: Various advances have been made in treating IgE-mediated food allergies. A phase II clinical trial of a second anti-IgE antibody, omalizumab, was recently initiated in subjects with peanut allergy, but was stopped as a result of safety concerns after severe reactions occurred during initial oral challenges. Oral immunotherapy is showing promise in various studies on patients with IgE-mediated food allergies. Gastrointestinal food allergic disorders involving non-IgE-mediated food allergies have recently received attention, particularly eosinophilic esophagitis. Although amino acid-based formula therapy remains the most successful in controlling inflammation and symptoms in these disorders, other therapeutic options including various dietary elimination protocols and swallowed fluticasone are showing success. Anti-IL-5 therapy may prove to be a promising future therapeutic option for refractory patients. SUMMARY: Although there are no specific therapeutic recommendations for many IgE-mediated and non-IgE-mediated food allergic disorders besides allergen avoidance, various novel approaches are currently being investigated and may influence treatment approaches in the future.     

Immune complexes in food-induced arthralgia

Ten patients are described who, in addition to other allergic symptoms, suffered from arthralgia. Dietary exclusion relieved the symptoms and specific food challenge reproduced them. IgG anti-IgE autoantibodies were high in patients with arthralgia in the serum and in the synovial fluid as compared with normals and the majority of patients with rheumatoid arthritis, traumatic arthralgia, and osteoarthritis used as controls. In three food-allergic patients IgG anti-IgE was detectable in a complexed form in the serum samples examined before and after food challenge. The finding of IgG anti-IgE autoantibody in a group of patients with allergic arthralgia is quite exciting. It raises the possibility of distinguishing a subgroup of arthralgic patients not having a classical rheumatoid arthritis, who may have a definable external exacerbating cause for their symptoms. A larger detailed survey is now in progress.     

IgE antibody-specific activity in human allergic disease

IgE antibody concentration, affinity, clonality and specific activity (also known as the allergen-specific IgE to total IgE ratio) influence the translation of IgE responses into clinically evident allergic symptoms following allergen exposure. Reported IgE-specific activity levels >3–4% place allergic individuals undergoing anti-IgE (Omalizumab^®) therapy at a disadvantage for poor resolution of their allergy symptoms following manufacturer’s recommended dosing schemes. We investigated the hypothesis that the specific activity of the IgE antibody response is highly variable with respect to age, allergen specificity and an individual’s total serum IgE level. Second, we investigated whether the IgE-specific activity level influences the extent and rate of loss of effector cell mediator release. IgE-specific activity distributions were plotted against age, allergen specificity and total serum IgE using 18,950 paired total IgE and allergen-specific IgE antibody data obtained from the analysis of sera from 3,614 allergic subjects and covering 182 allergen specificities. The fraction of specific IgE antibody of the total serum IgE was dependent on age of the individual, epitope specificity (clonality) and total serum IgE. The youngest group of allergic individuals with the lowest total serum IgE levels tended to have the highest allergen-specific IgE to total IgE ratios. Hymenoptera venom (54%), peanut (33%) and milk (27%) were the three allergen specificities that elicited the highest frequency of IgE-specific activities >4% among sensitized individuals. A prospective double-blind, placebo-controlled clinical study involving anti-IgE treatment of cat-allergic subjects showed IgE-specific activity was remarkably constant over the 16-week course of treatment, despite the up to 8-fold rise in total serum IgE following repetitive Omalizumab^® administration. Changes in specific and total IgE levels paralleled each other in patients receiving anti-IgE therapy. The fastest rate of reduction in cat allergen-induced basophil histamine release following anti-IgE therapy was observed when the cat-specific IgE to total IgE ratio was <2.5%. This reflected the more rapid loss of surface cat-specific IgE antibody with anti-IgE therapy in allergic individuals who displayed a more diverse IgE antibody repertoire. We conclude that IgE-specific activity is an age-, IgE heterogeneity- and total serum IgE-dependent variable that influences the magnitude of effector cell mediator release, and by inference, ultimate allergic symptom induction.     

Acute eosinophilic pneumonia associated with amitriptyline in a hemodialysis patient.

Drugs are well known causes of eosinophilic lung disease. In many patients, drug-induced eosinophilic lung disease presents with transient eosinophilic infiltrates that disappear after discontinuation of the drug. Some patients, however, experience a fulminant, acute eosinophilia-like disease. Recently, we experienced a case of amitriptyline-associated acute eosinophilic pneumonia with respiratory failure in a diabetic hemodialysis patient. Eight days after treatment with amitriptyline, sudden fever, chill, dry cough and dyspnea developed. Subsequently, multiple patch consolidations appeared on the chest radiographs. Bronchoalveolar lavage (BAL), established a diagnosis of acute eosinophilic pneumonia. After immediate discontinuation of amitriptyline, a rapid clinical and radiological improvement was observed. The present case indicates that the possibility of acute eosinophilic pneumonia should be fully considered in dialysis patients developing unexplained respiratory symptoms while on amitriptyline therapy.     

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.