Molecular concepts of IgE-initiated inflammation in atopic and nonatopic asthma

Omalizumab for STAT3 Hyper-IgE Syndromes in Adulthood: A Case Report and Literature Review

Background

Hyper-immunoglobulin E (IgE) syndromes (HIES) are a group of primary immune deficiencies disorders (PID) characterized by elevated serum IgE, eczema, recurrent skin, or respiratory system infections and may also be accompanied by some connective tissues and skeletal abnormalities. Currently, there is no complete cure or targeted treatment for HIES. Omalizumab is a humanized recombinant monoclonal antibody against IgE, reducing the level of free IgE, inhibiting the binding of IgE to receptors on the surface of effector cells, and reducing the activation of inflammatory cells and the release of multiple inflammatory mediators. However, the effect of omalizumab in treating HIES remains unknown. Herein, we described a case of an AD-HIES patient with chronic airway disease who benefited from omalizumab treatment.

Case Presentation

A 28-year-old Chinese woman was admitted for recurrent cough for 7 years, markedly elevated serum IgE level, and recurrent pneumonia caused by multiple pathogens, such as Pneumocystis jirovecii, Cytomegalovirus, Staphylococcus aureus, Aspergillus, and Mycobacterium tuberculosis. She had eczema-dermatitis, skin abscess, slightly traumatic fracture since childhood, and developed asthma and allergic bronchopulmonary aspergillosis (ABPA) lately. Using whole-exome sequencing, the STAT3 (c.1294G>T, p.Val432Leu) missense mutation for the autosomal dominant hyper-IgE syndrome was identified, and omalizumab was prescribed at 300 mg every 2 weeks. The patient responded well with the improvement of respiratory symptoms and lung function tests. The level of serum IgE remained stable on follow-up.

Conclusion

Omalizumab treatment proved beneficial in the case of HIES, especially with chronic airway disease, for which therapeutic options are limited. However, larger-scale prospective studies and long-term follow-up are required to establish the efficacy and safety of this therapeutic intervention.

Omalizumab and IgE in the Control of Severe Allergic Asthma

Omalizumab, a human immunoglobulin (Ig)G1 antibody against IgE, is a therapeutic agent for bronchial asthma. The Global Initiative for Asthma guidelines indicate that the use of omalizumab should be considered as an option in step 5 of treatment for patients with the most severe type of bronchial asthma. In patients with atopic asthma who are at a high risk of exacerbation, and in whom symptoms are poorly controlled despite treatment with inhaled corticosteroids, omalizumab is one of the few drugs that improves symptoms, reduces the risk of exacerbation, and improves the quality of life while offering a high level of safety. On the other hand, the associated treatment costs are high, and there are no clear methods to identify responders. A recent study suggested that evaluating the therapeutic effects and monitoring the pharmacokinetics of omalizumab could improve the success of omalizumab therapy. This review outlines the relationship between IgE-targeted therapy and the serum level of IgE to enhance the current understanding of the mechanism of omalizumab therapy. It also describes the clinical significance of measuring serum free IgE levels and monitoring omalizumab therapy.

Serum allergen-specific IgE reactivity: is there an association with clinical severity and airway eosinophilia in asthmatic cats?

OBJECTIVES

The aim of this study was to evaluate the results of serum allergen-specific IgE testing in cats with a clinical diagnosis of asthma and to determine if the number of allergens with positive IgE reactivity and magnitude of positive IgE responses would be associated with the severity of clinical signs or airway eosinophilia.

METHODS

Medical records from 2008 to 2018 were retrospectively reviewed. Inclusion required a diagnosis of feline asthma based on consistent clinicopathologic features and bronchoalveolar lavage (BAL) cytology with >10% eosinophils; additionally, cats needed to have the results of serum allergen-specific IgE tests.

RESULTS

Eighteen cases satisfied the inclusion criteria. Median age was 5 years and the most common presenting clinical sign was cough (n = 10/18). Most cats lived exclusively indoors (n = 13/18). The median percentage of BAL eosinophils was 47%. Serum allergen-specific IgE testing supported an underlying allergic etiology in 14/18 (78%) cats, with all but one having polysensitization. The severity of clinical signs and magnitude of airway eosinophilia did not correlate with the degree of positive IgE reactivity.

CONCLUSIONS AND RELEVANCE

This study identified a strong association between the identification of allergen-specific IgE and cats with asthma, and the majority of these cats were polysensitized. However, larger numbers of allergens with positive IgE reactivity or magnitude of IgE reactivity were not significantly associated with clinical severity or airway eosinophilia. Knowledge of positive allergen-specific IgE results could guide allergen avoidance, regardless of the magnitude of IgE reactivity.

Effects of omalizumab on basophils: Potential biomarkers in asthma and chronic spontaneous urticaria

Omalizumab is an anti-IgE humanized monoclonal antibody approved for the treatment of severe asthma and chronic spontaneous urticaria. Omalizumab binds free serum IgE and antagonizes its interaction with FcεRI, which is considered the main pharmacodynamic mechanism responsible for the clinical response to the treatment. The reduction of IgE serum concentration down-regulates the cellular expression of FcεRI on basophils. However, the biological events occurring on basophils during the therapy with omalizumab are multiple and complex. Here we review the current evidence regarding the specific biological effects of omalizumab on basophils in patients with asthma and chronic spontaneous urticaria. In addition to the modulation of IgE receptors, omalizumab may affect basophils homeostasis, intra-cellular signaling, cellular responsiveness/activation and cytokine release. These effects may be partially responsible for the clinical success of omalizumab and potentially provide useful biological markers for future assessment of the clinical response to the treatment. However, further investigation is required to better elucidate the role of basophils during the treatment with omalizumab.

Assessing the effect of 5-hydroxymethylfurfural on selected components of immune responses in mice immunised with ovalbumin

BACKGROUND

5-Hydroxymethylfurfural (5-HMF) is one of the most important products of the Maillard reaction. In recent years, many profitable biological effects of this compound have been demonstrated. This study sought to elucidate the anti-allergic effect of 5-HMF by investigating some selected components of the immune response in BALB/c mice immunised with ovalbumin (OVA).

RESULTS

Immunised animals had an increased level of serum total and OVA-specific antibodies when compared to the control (P < 0.01).We found that the OVA-induced increase in serum IgE and OVA-specific IgE were significantly suppressed in the groups treated with 5-HMF (P < 0.05). Moreover, interleukin-4 (IL-4) and interferon gamma (IFN-γ) were significantly reduced in a dose-independent manner when compared to the sensitised group (P < 0.05).

CONCLUSION

5-HMF inhibited the up-regulation of total and OVA-specific IgE through the suppression of the Th2-type immune response in immunised BALB/c mice. 5-HMF could therefore be a novel therapeutic approach for the prevention of IgE-mediated allergic diseases. © 2017 Society of Chemical Industry.

Serum free IgE guided dose reduction of omalizumab: a case report

BACKGROUND

Omalizumab is a human IgG1 antibody against IgE used as a therapy for sever asthmatic patients with asthma. According to the guidelines of the Global Initiative for Asthma, omalizumab is an add-on drug at treatment step 5 that is used for severe asthma patients who are allergic to perennial allergens. The effects of omalizumab for severe asthma therapy have been validated in multiple clinical studies. However, the long-term effects of omalizumab on IgE production and possibility of resetting of administration dose of omalizumab remain unknown.

CASE PRESENTATION

The serum total and free IgE levels were measured over time in a 63-year-old female patient with allergic asthma who was administered 375 mg omalizumab biweekly for 36 months. Her symptoms did not worsen and clinical course remained favorable after reducing the dose to 375 mg per month. The serum free IgE levels temporarily increased following a dose reduction of omalizumab. The serum free IgE trough level temporarily increased at 4 weeks after capable to reduce the dosage; however, thereafter, the serum free IgE level decreased to desired levels (below 30 ng/mL).

CONCLUSIONS

The present case shows the possibility of reducing the dose following the long-term use of omalizumab. Considering the high medical cost of omalizumab, the dose reduction may be a viable option. It may be useful to measure the serum free IgE level to appropriately identify patients in whom the dose can be reduced, and to carefully monitor the clinical course.

Allergic and Nonallergic Asthma Have Distinct Phenotypic and Genotypic Features

BACKGROUND

Identification of asthma phenotypes enables a better understanding and management of this heterogeneous disease. Studies have reported associations between human leukocyte antigens (HLA) and asthma in different populations, but the results have been inconclusive and they have rarely considered the distinct disease phenotypes. Our objective was to characterize allergic and nonallergic asthma phenotypes and evaluate possible associations with the HLA system.

METHODS

A total of 109 patients with asthma were prospectively followed during 2 years. They were divided into 2 groups, i.e., allergic and nonallergic asthma, according to their clinical history and skin prick test and serum-specific immunoglobulin E (IgE) results. The control group comprised 297 deceased donors of solid organs. Patients' features and HLA class I and II genotypes were assessed and compared.

RESULTS

This study showed different features between asthma phenotypes. Nonallergic patients were older at the onset of asthma symptoms and had a higher rate of intolerance to nonsteroidal anti-inflammatory drugs. Allergic patients had higher total serum IgE levels, reported atopic dermatitis and rhinoconjunctivitis more frequently, and, unexpectedly, had a greater disease severity. New associations between the HLA genotypes and allergic and nonallergic asthma were identified. The HLA-B*42, HLA-C*17, HLA-DPA1*03, and HLA-DPB1*105 genotypes were associated with allergic asthma and the HLA-B*48 genotype with the nonallergic phenotype. The presence of the haplotype HLA-DPA1*03 DQA*05 was associated with allergic asthma, and the presence of HLA-DPA1*03 and the absence of HLA-DQA*05 with nonallergic asthma.

CONCLUSIONS

Allergic and nonallergic asthma have distinct phenotypic and genotypic features. New associations between asthma phenotypes and HLA class I and II were identified.

Asthma phenotypes and IgE responses

The discovery of IgE represented a major breakthrough in allergy and asthma research, whereas the clinical interest given to IgE in asthma has been blurred until the arrival of anti-IgE biotherapy. Novel facets of the complex link between IgE and asthma have been highlighted by the effect of this treatment and by basic research. In parallel, asthma phenotyping recently evolved to the concept of endotypes, relying on identified/suspected pathobiological mechanisms to phenotype patients, but has not yet clearly positioned IgE among biomarkers of asthma.In this review, we first summarise recent knowledge about the regulation of IgE production and its main receptor, FcεRI. In addition to allergens acting as classical IgE inducers, viral infections as well as air pollution may trigger the IgE pathway, notably resetting the threshold of IgE sensitivity by regulating FcεRI expression. We then analyse the place of IgE in different asthma endo/phenotypes and discuss the potential interest of IgE among biomarkers in asthma.

Impact of atopy on asthma and allergic rhinitis in the cohort for reality and evolution of adult asthma in Korea

PURPOSE

Atopy is an important cause of asthma. Few data on the prevalence of atopy or comparisons with clinical characteristics of asthma in Korean patients have been published. We evaluated the effects of atopy on clinical profiles and airway inflammation in Korean asthmatics.

METHODS

We retrospectively enrolled 1,492 asthmatics from the Cohort for Reality and Evolution of Adult Asthma in Korea (COREA) cohort who had undergone skin prick tests for aeroallergens. The patients' clinical characteristics, lung function, PC20, and sputum and blood inflammatory cell counts were compared based on the presence or absence of atopy. Atopy was defined as one or more positive reactions (A/H ratio >1) on a skin prick test.

RESULTS

Among 11 aeroallergens, house dust mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus) were the most prevalent cause of a positive skin prick test. As compared with non-atopic asthmatics, atopic asthmatics showed early onset of the disease. Atopic patients with asthma had a higher FEV1, FVC, and FEV1/FVC as compared with non-atopic patients with asthma. In addition, asthmatics without atopy had more uncontrolled asthma (P=0.001) and severe rhinitis (P<0.05) as compared with atopic asthmatics. Smoking, as measured in pack years, was higher in the non-atopic asthmatics than in the atopic asthmatics. The erythrocyte sedimentation rate was higher in non-atopic asthmatics than in the atopic asthmatics and patients with non-atopic asthma had a higher sputum neutrophil count than did those with atopic asthma.

CONCLUSIONS

Our data indicate that atopic asthmatics had an early onset of disease and high IgE levels, while the non-atopic asthmatics had decreased lung function and a high sputum neutrophil count, suggesting that a different approach is needed to treat atopic asthma.

sICAM-1 and TNF-α in asthma and rhinitis: relationship with the presence of atopy

BACKGROUND

A genetically determined overproduction of specific immunoglobulin E (IgE) underlies many diseases like asthma or allergic rhinitis. IgE as well as tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) play a critical role in the induction and maintenance of inflammation. While the correlation between IgE and atopy is inseparable, little is known about the correlation of atopy with markers of inflammation.

OBJECTIVE

We investigated the relationship between the serum concentrations of TNF-α, soluble ICAM-1 (sICAM-1), and the presence of atopy in patients with persistent rhinitis or asthma.

METHODS

Serum concentrations of sICAM-1, TNF-α, and total IgE were investigated in 64 adults with persistent allergic rhinitis, 17 subjects with nonatopic rhinitis, 90 patients with asthma, and 21 healthy individuals. Atopy was diagnosed on the basis of positive family history, skin prick tests, and serum IgE concentration.

RESULTS

Total IgE concentration was significantly higher in patients with atopic rhinitis or asthma when compared with nonatopic patients and healthy individuals and was the highest in patients suffering from severe atopic asthma who were not treated with systemic glucocorticosteroids. Although there were marked alterations in IgE in atopic and nonatopic patients, there were no significant differences between atopic and corresponding groups of nonatopic rhinitic and asthmatic patients in sICAM-1 and TNF-α concentrations. (sICAM-1 in rhinitis: atopic vs. nonatopic patients: 224.02 and 221.08 ng/ml, respectively, p > .05; in mild/moderate asthma: atopic vs. nonatopic: 306.22 and 326.39 ng/ml, respectively, p > .05; severe asthma without oral corticosteroids therapy: atopic vs. nonatopic: 418.03 and 468.09 ng/ml, respectively, p > .05; and severe asthma with oral corticosteroids therapy: atopic vs. nonatopic: 320.66 and 308.09 ng/ml, respectively, p > .05).

CONCLUSIONS

Concentrations of sICAM-1 and TNF-α are significantly higher in patients with asthma compared with those observed in patients with rhinitis, but they are independent of the presence of atopy.

Serum IgE reactivity profiling in an asthma affected cohort

BACKGROUND

Epidemiological evidence indicates that atopic asthma correlates with high serum IgE levels though the contribution of allergen specific IgE to the pathogenesis and the severity of the disease is still unclear.

METHODS

We developed a microarray immunoassay containing 103 allergens to study the IgE reactivity profiles of 485 asthmatic and 342 non-asthmatic individuals belonging to families whose members have a documented history of asthma and atopy. We employed k-means clustering, to investigate whether a particular IgE reactivity profile correlated with asthma and other atopic conditions such as rhinitis, conjunctivitis and eczema.

RESULTS

Both case-control and parent-to-siblings analyses demonstrated that while the presence of specific IgE against individual allergens correlated poorly with pathological conditions, particular reactivity profiles were significantly associated with asthma (p<10E-09). An artificial neural network (ANN)-based algorithm, calibrated with the profile reactivity data, correctly classified as asthmatic or non-asthmatic 78% of the individual examined. Multivariate statistical analysis demonstrated that the familiar relationships of the study population did not affect the observed correlations.

CONCLUSIONS

These findings indicate that asthma is a higher-order phenomenon related to patterns of IgE reactivity rather than to single antibody reactions. This notion sheds new light on the pathogenesis of the disease and can be readily employed to distinguish asthmatic and non-asthmatic individuals on the basis of their serum reactivity profile.

TACI-Ig prevents the development of airway hyperresponsiveness in a murine model of asthma

BACKGROUND

Increased levels of serum IgE are associated with greater asthma prevalence and disease severity. IgE depletion using an anti-IgE monoclonal antibody has met with success in the treatment of moderate-to-severe and severe persistent allergic asthma.

OBJECTIVE

To test whether B cell-targeted therapy is a more effective treatment for airway hyperresponsiveness (AHR) in a murine model compared with IgE-depletion.

METHODS

We delivered soluble mTACI-Ig, a receptor for the B cell survival factors BLyS (B Lymphocyte Stimulator) and APRIL (A PRoliferation-Inducing Ligand), or anti-IgE to allergen-sensitized mice before airway challenge with allergen.

RESULTS

mTACI-Ig treatment reduced circulating mature B cell levels in the blood, while anti-IgE treatment had no effect on B cell counts. Both mTACI-Ig and anti-IgE decreased the levels of total and allergen-specific IgE in the serum. Histopathologic analysis of lungs showed a reduction in disease severity scores for both treatment groups, but results were more pronounced in mTACI-Ig-treated mice. Neutrophil and eosinophil numbers in the bronchoalveolar lavage (BAL) were significantly reduced following mTACI-Ig treatment, but not after anti-IgE delivery. BLyS and APRIL blockade also resulted in a significant decrease in IL-4 and eotaxin mRNA and IL-4 and KC protein levels in total lung homogenates and BAL fluid, respectively. Finally, mTACI-Ig treatment was more effective than anti-IgE treatment in reducing AHR to inhaled antigen.

CONCLUSIONS

Our data demonstrate that delivery of mTACI-Ig is a more effective treatment than anti-IgE mAb in a murine model of AHR.

Sinonasal pathology in nonallergic asthma and COPD: 'united airway disease' beyond the scope of allergy

BACKGROUND

In contrast to the epidemiological and clinical association between allergic rhinitis and asthma, upper airway inflammation is less characterized in patients with nonatopic asthma and virtually unexplored in chronic obstructive pulmonary disease (COPD). Here, sinonasal pathology is studied in patients with allergic asthma, nonallergic asthma and COPD.

METHODS

Ninety patients with stable bronchial disease were included in the study, of which 35 were diagnosed with allergic asthma, 24 with nonallergic asthma and 31 with COPD. Concurrently, 61 control subjects without pulmonary disease were included and matched for age and smoking habits respectively with the asthma and the COPD group. Sinonasal symptoms were evaluated on a visual analogue scale and rhinosinusitis-related impairment of quality of life was assessed with the sino-nasal outcome test-22 (SNOT-22) questionnaire. Nasal mucosal abnormalities were quantified with nasal endoscopy and nasal secretions collected for measuring inflammatory mediators.

RESULTS

Allergic asthmatics, nonallergic asthmatics and COPD patients reported more nasal symptoms than their respective control subjects, had a higher SNOT-22 score and presented more mucosal abnormalities in the nose. Nasal secretions of both allergic and nonallergic asthmatics contained higher levels of eotaxin, G-CSF, IFN-gamma and MCP-1 than controls. Allergic asthmatics had higher nasal IP-10 levels as well. COPD-patients had higher nasal levels of eotaxin, G-CSF and IFN-gamma than controls.

CONCLUSION

Patients with allergic and nonallergic asthma and COPD show increased nasal symptoms and more nasal inflammation. Hence, our data confirm the 'united airways' concept to be beyond the scope of allergic asthma.

Novel clinical and serological aspects in non-allergic asthma

BACKGROUND

We have recently observed that skin reactivity to autologous serum injection is common in patients with non-allergic asthma. However, clinical significance of skin reactivity to autologous serum remains to be defined.

OBJECTIVE

To evaluate the possible relation between skin reactivity to autologous serum and clinical and laboratory characteristics in a series of patients with non-allergic asthma.

METHODS

Fifty-five patients with non-allergic asthma underwent in vivo autologous serum skin test (ASST) and in vitro basophil histamine release assay using basophils from a normal donor. Clinical and laboratory characteristics including peripheral blood eosinophilia, antinuclear antibodies and total IgE concentration were evaluated. As control, ASST was performed in 10 allergic asthmatic patients, 10 patients with allergic rhinitis and 10 normal subjects.

RESULTS

ASST was positive in 29/55 non-allergic asthmatics (53%), whereas it was negative in all 30 control subjects (P<0.001). The sera of 6 out of 51 patients induced in vitro histamine release from autologous basophils. The sera from two patients induced histamine release from membrane IgE-stripped basophils. A significant predominance of female sex (83%) and a high incidence of antinuclear antibodies (ANA) positivity (55%) were found among ASST-positive patients.

CONCLUSION

These findings indicate that ASST is positive in about half patients with non-allergic asthma and that a proportion of patients (16%) has functional evidence of circulating histamine-releasing factors. In addition, predominance of female sex and frequent ANA positivity are in line with an autoimmune basis of non-allergic asthma.

Anti-IgE antibodies for the treatment of IgE-mediated allergic diseases

The pharmacological purposes of the anti-IgE therapy are to neutralize IgE and to inhibit its production to attenuate type I hypersensitivity reactions. The therapy is based on humanized IgG1 antibodies that bind to free IgE and to membrane-bound IgE on B cells, but not to IgE bound by the high-affinity IgE.Fc receptors on basophils and mast cells or by the low-affinity IgE.Fc receptors on B cells. After nearly 20 years since inception, therapeutic anti-IgE antibodies (anti-IgE) have been studied in about 30 Phase II and III clinical trials in many allergy indications, and a lead antibody, omalizumab, has been approved for treating patients (12 years and older) with moderate-to-severe allergic asthma. Anti-IgE has confirmed the roles of IgE in the pathogenesis of asthma and helped define the concept "allergic asthma" in clinical practice. It has been shown to be safe and efficacious in treating pediatric allergic asthma and treating allergic rhinitis and is being investigated for treating peanut allergy, atopic dermatitis, latex allergy, and others. It has potential for use to combine with specific and rush immunotherapy for increased safety and efficacy. Anti-IgE thus appears to provide a prophylactic and therapeutic option for moderate to severe cases of many allergic diseases and conditions in which IgE plays a significant role. This chapter reviews the evolution of the anti-IgE concept and the clinical studies of anti-IgE on various disease indications, and presents a comprehensive analysis on the multiple intricate immunoregulatory pharmacological effects of anti-IgE. Finally, it reviews other approaches that target IgE or IgE-expressing B cells.

Autologous serum skin test reactivity in patients with non-allergic asthma

BACKGROUND

Inflammatory alterations of respiratory airways have been found in patients with non-allergic asthma, but the triggering event has not been defined. An autoimmune activation of inflammatory cells has been hypothesized.

OBJECTIVE

To evaluate whether histamine-releasing factors are present in sera from non-allergic asthmatics.

METHODS

Twenty-four patients with non-allergic asthma underwent in vivo autologous serum skin test (ASST) and in vitro basophil histamine release assay using autologous basophils as well as basophils from normal donors. Twenty-seven subjects with respiratory allergy and three normal subjects were chosen as control.

RESULTS

ASST was positive in 14/24 non-allergic asthmatics (58%) whereas it was negative in all 30 control subjects (P<0.001). The serum of only one ASST-positive patient out of 12 (8.4%) induced in vitro histamine release from autologous basophils. The serum from another ASST-positive patient induced histamine release from membrane IgE-stripped autologous basophils. Sera from either non-allergic asthmatics or from control subjects did not provoke significant histamine release from basophils from three normal donors.

CONCLUSION

Skin reactivity to autologous serum is common among non-allergic asthmatics, indicating the presence of circulating histamine-releasing factors. However, only in a minority of patients in vitro functional evidence of histamine-releasing autoantibodies (anti-FcepsilonRI or anti-IgE) was obtained. The presence of circulating histamine-releasing factors might contribute to initiation/maintenance of inflammation in respiratory airways of non-allergic asthmatics.

T cell and eosinophil activation in mild and moderate atopic and nonatopic children's asthma in remission

BACKGROUND

Inflammation in the pathogenesis of asthma is associated with products of activated T cells and eosinophils. The aim of this study was to determine whether ongoing inflammation persists in children with different phenotypes of asthma despite the disease in remission.

METHODS

Serum samples were collected from 68 children with atopic or nonatopic asthma in remission and from 15 healthy children. Soluble interleukin-2 receptor (sIL-2R), IL-2 and IL-4 were examined by using an enzyme-linked immunosorbent assay. Total and specific immunoglobulin E, and eosinophil cationic protein (ECP) were analysed by fluoroimmunoassay (Pharmacia CAP System).

RESULTS

In patients with moderate persistent atopic asthma, sIL-2R was increased significantly when compared with mild persistent atopic asthma (P < 0.05). No changes of sIL-2R were seen in nonatopic asthmatics compared with atopics and controls. The level of IL-2 was elevated in moderate persistent atopic and nonatopic asthmatic children compared with controls (P < 0.05 and P < 0.05 respectively) and compared with mild persistent atopic asthmatics and mild persistent nonatopic asthmatics (P < 0.05 in both cases). The levels of IL-4 in most patients and controls remained below the sensitivity of the assay. Eosinophil cationic protein levels in moderate persistent atopic and nonatopic asthmatics were significantly higher than in mild persistent asthma severity cases (P < 0.001 and P < 0.01 respectively) and in healthy children (P < 0.01 in both cases).

CONCLUSION

Changes in the concentration of sIL-2R, IL-2 and ECP reflect increased T cell and eosinophil activity in relation to the level of severity of asthma in atopic and nonatopic children, thereby proving the presence of persistent inflammation despite the absence of disease symptoms.

[Total IgE in the sputum and serum of patients with asthma]

BACKGROUND

The correlation between total IgE in induced sputum (IS) and serum is not well defined. The aim of this study was to investigate the relationship between total IgE in IS and total IgE in serum and airway inflammation.

METHODS

Twenty-one patients with stable asthma and thirteen healthy controls were studied. Clinical and spirometric data were collected and a skin prick test to the 13 most common aeroallergens in our area was performed in all subjects. Total IgE in IS and serum was determined by the UNICAP immunoanalysis system (Pharmacia Uppsala, Sweden) while albumin concentration in IS and serum was determined using the Cobas Integra turbidimetric method (Roche Diagnostics, Basel, Switzerland).

RESULTS

The percentage of eosinophils in EI was 8.7 (11.8) in asthmatic subjects and was 0.5 (1) in healthy controls. Total IgE (KU/L) was 43.2 (23) in asthmatics vs 25.6 (3) in healthy controls in IS, and was 329 (413) in asthmatics vs 57 (78) in controls in serum. Total IgE in IS was significantly correlated with total IgE in serum; r = 0.71 (p = 0.048), but not with the albumin relative index. No correlation was found between IgE and the number of eosinophils in IS.

CONCLUSIONS

Total IgE can be measured in IS. Total IgE in IS is mildly correlated with total IgE measured in serum. The lack of correlation between total IgE and albumin in IS suggests that IgE in IS could be locally produced, at least in part.

The pathophysiology of airway dysfunction

Asthma and chronic obstructive pulmonary disease (COPD) are distinct inflammatory disorders with differing pathophysiologic mechanisms, different clinical courses, and, therefore, distinct treatment strategies. Whereas in asthma airflow limitation is typically episodic and reversible, airflow limitation in COPD is progressive and only partially reversible. In contrast to asthma, which is characterized by an elevated number of eosinophils in the blood and the accumulation of elevated numbers of activated eosinophils, mast cells, and CD4+ T(H)2-lymphocytes in the lungs, the primary inflammatory cells present in the lungs of patients with stable COPD are neutrophils, macrophages, and CD8+ lymphocytes. Bronchoconstriction in COPD is largely regulated by cholinergically mediated vagal tone, and the pathologic processes of COPD further reduce airway patency. Bronchodilators, most notably anticholinergics, are recommended as first-line pharmacologic therapy for COPD. Proper use of inhaled anticholinergic medications has been shown to lead to significant reversibility of acetylcholine-mediated bronchoconstriction during both stable disease and exacerbations of COPD. For patients with asthma, current guidelines recommend anti-inflammatory medications, specifically inhaled corticosteroids and leukotriene-modifiers, as first-line therapy, making these agents the mainstay of asthma therapy. In contrast, the current guidelines for COPD management recommend that inhaled anti-inflammatory agents be tried in patients with COPD only as second-line therapy for patients who have severe to very severe airflow obstruction with frequent exacerbations and who remain symptomatic despite maximized bronchodilation with multiple inhaled bronchodilators. Hence, it is extremely important to understand the differences between the underlying pathogenesis and pathophysiology of COPD and those of asthma, as these differences dictate the implementation of distinctly different treatment options for these 2 diseases.

Interrelationships among asthma, atopy, rhinitis and exhaled nitric oxide in a population-based sample of children

BACKGROUND

Exhaled nitric oxide (eNO) has attracted increasing interest as a non-invasive marker of airway inflammation in asthma. However, little evidence exists on the influences exerted on eNO by the interrelations among atopic status, asthma and rhinitis.

METHODS

Among the 1156 children who participated in a large-scale epidemiological survey on asthma and allergies (ISAAC II: International Study of Asthma and Allergies in Childhood Phase II) in the city of Clermont-Ferrand, 53 asthmatics without corticosteroid treatment and 96 non-asthmatics were invited to perform eNO and skin prick tests (SPTs) to 12 common allergens.

RESULTS

Atopic asthmatic children had higher eNO than non-atopic asthmatic children (28.9+/-9.1 vs. 17.1+/-13.1 p.p.b.; P=0.0004) with a significant increase when one SPT or more are positive (26.5+/-7.8 vs. 17.1+/-13.1 p.p.b.; P=0.03). Similarly, non-asthmatic, atopic subjects had higher eNO than non-atopic subjects with a significant increase when two SPTs or more are positive (19.4+/-9.8 vs. 11.7 +/-6.7 p.p.b.; P=0.003). In the case of equal levels of positive SPTs (0, 1, >/=2), asthmatic children always had higher eNO than non-asthmatic ones. Furthermore, among non-asthmatic children, the eNO level increased only in atopics who had rhinitis (20.7+/-13 vs. 12.5+/-6.4 p.p.b. in atopic controls (subjects without rhinitis and asthma) and 12.3+/-6.6 p.p.b. in non-atopic controls; P=0.001), whereas among asthmatic children, eNO level increased in atopics independently of rhinitis (28.2+/-9.5 p.p.b. in those with rhinitis and 30.9+/-8.1 p.p.b. in those without) as well as in non-atopics with rhinitis (22.5+/-17.2 p.p.b.).

CONCLUSIONS

Our data suggest that besides atopy and asthma, allergic rhinitis should also be taken into account in the assessment of eNO.

Airway inflammation and basement membrane tenascin in newly diagnosed atopic and nonatopic asthma

Previous studies have shown both similar and distinct inflammatory changes in atopic and nonatopic asthma. This study was set to investigate the bronchial inflammatory cell infiltrate and subepithelial basement membrane (BM) tenascin deposition in subjects with newly diagnosed asthma and bronchial hyperresponsiveness (BHR). Seventy-nine asthmatic subjects (age 18-60 years) were recruited and 58 were atopic according to skin prick testing. The patients recorded asthma symptoms and peak flow measurements for 14 days. Lung function and BHR were measured by spirometry and histamine challenge. Serum eosinophil cationic protein (ECP) and blood eosinophils were assessed. Fiberoptic bronchoscopy was performed to obtain bronchial biopsies. Serum ECP was higher in the atopic group but eosinophil counts did not differ. There were no differences in inflammatory cells studied (activated eosinophils, T-lymphocytes, mast cells or macrophages) between nonatopic and atopic subjects. BM tenascin layer was significantly thicker in atopic compared with nonatopic subjects (7.6 vs 6.3 microm, P = 0.007). The thickness of tenascin correlated with eosinophil, T-lymphocyte, and macrophage counts, as well as with IL-4-positive cell counts and the correlation was seen only in atopic asthmatics. These findings suggest that inflammatory cells may have a regulatory role in tenascin expression in atopic asthma.

Links between rhinitis and asthma

There is compelling evidence of a close relationship between the upper and lower airways in asthma and rhinitis. Rhinitis is present in the majority of patients with asthma, and a significant minority of patients with rhinitis have concomitant asthma. Similarities between the two conditions occur in the nature of the inflammation present in the target tissues. A common initiating step in the inflammatory process of allergic airways disease is the presence of immunoglobulin E providing an adaptor molecule between the offending allergen and inflammatory cell activation and mediator release. Differences in the two conditions arise largely from the structural differences between the nose and the lungs. In an asthmatic, concomitant allergic rhinitis increases healthcare costs and further impairs quality of life. The presence of rhinitis should always be investigated in children and young adults with asthma. Subjects with allergic rhinitis have an increased risk of developing asthma and may form a suitable population for secondary intervention to interrupt the 'allergic march'.

Atopic asthma and TNF-308 alleles: linkage disequilibrium and association analyses

The association of a tumor necrosis factor -308 allele (TNF2) to asthma has been reported in some studies but not in others. The aim of this study was to test this association in a population recruited on the basis of allergy to Parietaria. In the study population, asthma was positively associated to HLA-DRB1*03 (p = 0.01) and to the haplotype TNF2/DRB1*03 (p = 0.02). In the parent subgroup, the proportion of asthmatics was increased in patients with TNF2 (p = 0.01), but the primary association of asthma was to the haplotype TNF2/DRB1*1104 (p = 0.005). The study population was subdivided according to prick skin test (ST) positivity to Lolium, Parietaria, and D. pteronyssinus. Asthma was associated to HLA-DRB1*03 and to the haplotype TNF2/DRB1*03 (p = 0.0015 and 0.0001, respectively) in patients ST positive to Lolium, and to the haplotype TNF2/DRB1*1104 (p = 0.025) in patients ST positive to Parietaria. The transmission disequilibrium test detected excess transmission of HLA-DRB1*03 and of the haplotype TNF2/DRB1*03 (p = 0.03 and 0.04, respectively) to siblings with asthma and ST positivity to Lolium and of HLA-DRB1*1104 and of the haplotype TNF2/DRB1*1104 (p = 0.04 and 0.015, respectively) to siblings with asthma and ST positivity to Parietaria. Taken together, these observations indicate that the haplotypes TNF2/DRB1*03 and TNF2/*B1*1104 contain alleles controlling atopic asthma in patients with sensitization to Lolium and Parietaria, respectively. This suggests that the association of asthma to TNF2 reflects linkage disequilibrium with genes influencing specific immune response.

Is there a role for treatment of asthma with omalizumab?

The allergic response is distinct from other immune reactions in its reliance on IgE, its high affinity receptor, Fc epsilon RI, and the primary effector cell--the tissue mast cell. Positive skin tests or raised concentrations of specific immunoglobulin E (IgE) in the serum define IgE sensitisation or "atopy". IgE participates both in immediate hypersensitivity response and in the induction of chronic allergic inflammation. It enhances allergen capture and Th2 cell activation, and may trigger other immunoregulatory pathways. Considerable effort in therapeutic research has focused on interference with IgE function because of its position high in the allergic cascade. Therapy with anti-IgE is one such approach that shows much promise.

Atypical nasal challenges in patients with idiopathic rhinitis: more evidence for the existence of allergy in the absence of atopy?

BACKGROUND

The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that many patients may have a localized form of allergic rhinitis in the absence of other atopic symptoms and markers. This study compares detailed nasal challenge results obtained from patients with idiopathic rhinitis to those of atopic and normal controls.

METHODS

Patients with idiopathic rhinitis (n = 23), perennial allergic rhinitis (n = 8) and normal controls (n = 8) underwent a normal saline challenge to exclude hyper-reactivity and then bilateral nasal allergen challenges. Nasal patency was assessed by anterior active rhinomanometry.

RESULTS

All of the patients with atopic rhinitis demonstrated positive bilateral allergen challenges. All normal control subjects had bilateral negative challenges. Two patients in the idiopathic group tested positively to saline and were excluded from further study with 62% of the remainder testing positive to allergens. Of the idiopathic patients testing positive, 85% were sensitive to house dust mite.

CONCLUSION

A significant proportion of patients with idiopathic rhinitis have positive nasal challenges, the vast majority to house dust mite allergen. These findings add to the weight of evidence that suggests 'localized allergy' may exist in the absence of systemic atopic markers.

Exhaled nitric oxide in asthmatic and non-asthmatic children: influence of type of allergen sensitization and exposure to tobacco smoke

Asthmatic bronchial inflammation is associated with increased nitric oxide concentrations in exhaled air (eNO). Recent data suggest that this effect arises from atopy. Our aim in this study was to find out whether atopy and sensitization to particular allergens influences eNO levels. A total of 213 subjects (41 asthmatics and 172 controls) (96 boys and 117 girls, 7.3-14 years of age) were studied. Parents completed a questionnaire that sought information on their children's respiratory symptoms and exposure to tobacco smoke. Subjects underwent skin-prick tests for the following common allergens: Dermatophagoides pteronyssinus (Dpt), cat fur, Aspergillus fumigatus, Alternaria tenuis, mixed grass, mixed tree pollen, Parietaria officinalis, egg, and cow's milk. eNO was collected in 1-l mylar bags (exhaled pressure 10 cmH2O, flow 58 ml/s) and analyzed by using chemiluminescence. Atopic and non-atopic children without a history of chronic respiratory symptoms had a similar geometric mean eNO (atopics, n = 28, 11.2 p.p.b.; non-atopics, n = 96, 10.0 p.p.b.; mean ratio 1.1, 95% confidence interval [CI]: 0.7-1.6). Conversely, atopic asthmatic subjects had significantly higher eNO values than non-atopic asthmatic subjects (atopics, n = 25, 24.8 p.p.b.; non-atopics, n = 16, 11.4 p.p.b.; mean ratio 2.2, 95% CI: 1.2-3.9, p= 0.000). In children with rhinitis alone (n = 15) and those with lower respiratory symptoms other than asthma (n = 33), eNO increased slightly, but not significantly, with atopy. eNO levels correlated significantly with Dpt wheal size (r = 0.51) as well with the wheal size for cat, mixed grass, and Parietaria officinalis (r = 0.30-0.29), and with the sum of all wheals (r = 0.47) (p= 0.000). Subjects sensitized only for Dpt (but not those subjects sensitized only for grass pollen or other allergens) showed significantly higher eNO levels than non-atopic subjects (16.4 p.p.b. vs. 10.2 p.p.b., mean ratio 1.6, 95% CI: 1.1-2.3, p= 0.002). In asthmatic subjects, Dpt sensitization markedly increased eNO levels (Dpt-sensitized subjects: 28.0 p.p.b.; Dpt-unsensitized subjects: 12.2 p.p.b.; mean ratio 2.3, 95% CI: 1.5-3.5, p= 0.000). Non-asthmatic Dpt-sensitized subjects also had significantly higher eNO values than non-asthmatic, non-Dpt-sensitized subjects (14.2 p.p.b. vs. 10.1 p.p.b.; mean ratio 1.4, 95% CI: 1.1-1.9, p= 0.008). No difference was found between eNO levels in asthmatic subjects and control subjects exposed or unexposed to tobacco smoke. In conclusion, eNO concentrations are high in atopic asthmatic children and particularly high in atopic asthmatics who are sensitized to house-dust mite allergen.

Autoanti-IgE antibodies in patients with allergic and idiopathic rhinitis

The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that, in a proportion of patients, it may be a more localized form of allergic rhinitis in the absence of other atopic symptoms and markers. Anti-IgE is thought to be a systemic marker of atopy. This study compared serum IgG autoanti-IgE levels in patients with idiopathic rhinitis, perennial allergic rhinitis and normal controls. Serum samples were obtained from 19 patients with idiopathic rhinitis, 17 patients with perennial allergic rhinitis and 10 normal non-rhinitic controls. The presence or absence of IgG1 and IgG4 anti-IgE antibodies was detected using enzyme-linked immunosorbent assays. Eighty-eight percent of the patients with perennial allergic rhinitis had raised levels of autoanti-IgE antibodies in their serum. None of the controls or patients with idiopathic rhinitis showed raised levels (P < 0.001). Although patients with idiopathic rhinitis may exhibit clinical and pathological features of allergy, they do not show raised levels of anti-IgE in their serum.

B-cell isotype control in atopy and asthma assessed with cDNA array technology

B-cell isotype switching and the production of IgE is regulated by a variety of gene products through different mechanisms. A better understanding of these processes has the potential to identify markers of disease and new therapeutic targets. The aim of the study was to investigate human B-cell isotype control and IgE production in atopy and asthma with cDNA array technology. Eighteen atopic asthmatic, eight atopic nonasthmatic, and fourteen healthy control subjects were included. Peripheral blood mononuclear cells were separated by gradient centrifugation, mRNA was purified, and the reverse-transcribed probes were hybridized to cDNA membranes. Group differences were assessed with the Mann-Whitney U-test. Twenty-three of seventy-eight tested IgE-related genes had significantly altered expression in atopy and asthma compared with that in the healthy subjects. The differentially expressed genes include surface molecules involved in T- and B-cell interaction and activation, cytokines, intracellular signaling products, and transcription factors. In conclusion, both atopic nonasthmatic and atopic asthmatic individuals had activated proinflammatory pathways, a minimal requirement for B-cell isotype switching, and a clear net pro-IgE cytokine climate.

Cytokine production from peripheral whole blood in atopic and nonatopic asthmatics: relationship with blood and sputum eosinophilia and serum IgE levels

BACKGROUND

The cytokine network is thought to be essential in orchestrating airway inflammation in asthma. Although evidence has accumulated to suggest that atopic asthma is a Th2 disease, much less is known about nonatopic asthma.

METHODS

We have compared the production of IL-4, IL-6, IFN-gamma, and TNF-alpha from peripheral blood leukocytes between atopic (n=21) and nonatopic (n=22) asthmatics and healthy nonatopic subjects (n=20). Peripheral blood was incubated for 24 h either without stimulus or with LPS or PHA. Cytokines were measured by the immunotrapping technique (Dynamic Immunoassay).

RESULTS

When compared to healthy nonatopic subjects, both atopic and nonatopic asthmatics showed increased blood and sputum eosinophilia associated with raised total serum IgE levels. Similarly, both asthma groups displayed spontaneous, endotoxin-induced overproduction of IL-6. Enhanced spontaneous, endotoxin-induced release of IL-4 combined with reduced spontaneous IFN-gamma production was seen only in atopic asthma. In this group of patients, the production of IL-4 was related to the extent of blood and sputum eosinophilia. In nonatopic asthmatics, serum levels of IgE were inversely related to the production of IFN-gamma.

CONCLUSIONS

Both atopic and intrinsic asthma display raised blood and airway eosinophilia, raised total serum IgE, and overproduction of IL-6 from peripheral blood. Atopic asthma is also characterized by impaired spontaneous release of IFN-gamma and increased production of IL-4 that correlates with the magnitude of eosinophilic inflammation.

The inhibitory receptor superfamily: potential relevance to atopy

The role of inhibitory receptor superfamily (IRS) members in the pathophysiology of atopy is still largely unexplored but the past year or so has brought at least three important advances in the understanding of IRS member function: first, several targets of an inositol-phosphatase-dependent inhibitory signaling pathway utilized by some IRS members were identified; second, there is accumulating evidence from murine models supporting the importance of inhibitory Fc gamma receptors in modulating immune-complex-mediated inflammation; third, the inhibitory signaling capability of several previously identified candidate IRS members--including several expressed on cell types implicated in atopy and allergic reactions--has been demonstrated.

Asthma, oxidant stress, and diet

It has been suggested that the increased prevalence of atopy and asthma observed in many developed countries over the past 30 y is in part the result of a decrease in the incidence and severity of early childhood infections. The immunologic consequence of this phenomenon has been the expansion of T-lymphocyte populations away from the T-helper 1 (Th1) subset and in the direction of the Th2 subset. This leads to the creation of a cytokine-mediated propensity for the development of an intense inflammatory response in the airways, resulting in oxidative stress, airway tissue injury, and the development of atopy and asthmatic symptomatology. Over this same period, there has been a decreased intake of dietary substances that contribute to antioxidant defense, and this appears to have contributed to the rise of atopy and asthma. Studies evaluating the efficacy of these antioxidant substances in the prevention of asthma and as adjuvants in the treatment of asthma are reviewed, and suggestions are made for the direction of future studies.