Immunoglobulin E: role in asthma and allergic disease: lessons from the clinic

Phenotyping of Severe Asthma in the Era of Broad-Acting Anti-Asthma Biologics

Severe asthma is associated with significant morbidity and mortality despite the maximal use of inhaled corticosteroids and additional controller medications, and has a high economic burden. Biologic therapies are recommended for the management of severe, uncontrolled asthma to help to prevent exacerbations and to improve symptoms and health-related quality of life. The effective management of severe asthma requires consideration of clinical heterogeneity that is driven by varying clinical and inflammatory phenotypes, which are reflective of distinct underlying disease mechanisms. Phenotyping patients using a combination of clinical characteristics such as the age of onset or comorbidities and biomarker profiles, including blood eosinophil counts and levels of fractional exhaled nitric oxide and serum total immunoglobulin E, is important for the differential diagnosis of asthma. In addition, phenotyping is beneficial for risk assessment, selection of treatment, and monitoring of the treatment response in patients with asthma. This review describes the clinical and inflammatory phenotypes of asthma, provides an overview of biomarkers routinely used in clinical practice and those that have recently been explored for phenotyping, and aims to assess the value of phenotyping in severe asthma management in the current era of biologics.

Effects of biological therapies on patients with Type-2 high asthma and comorbid obesity

Over 20 million adults and 6 million children in the United States (US) have asthma, a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, and mucus hypersecretion. Obesity, another highly prevalent disease in the US, is a major risk factor for asthma and a significant cause of diminished asthma control, increased submucosal eosinophilia, and reduced quality of life. A large subgroup of these patients experiences severe symptoms and recurrent exacerbations despite maximal dosage of standard asthma therapies. In the past two decades, the development of biological therapies has revolutionized the field and advanced our understanding of type 2 inflammatory biomarkers. However, patients with obesity and comorbid asthma are not principally considered in clinical trials of biologics. Large landmark cluster analyses of patients with asthma have consistently identified specific asthma phenotypes that associate with obesity but may be differentiated by age of asthma onset and inflammatory cell profiles in sputum. These patterns suggest that biologic processes driving asthma pathology are heterogenous among patients with obesity. The biological mechanisms driving pathology in patients with asthma and comorbid obesity are not well understood and likely multifactorial. Future research needs to be done to elicit the cellular and metabolic functions in the relationship of obesity and asthma to yield the best treatment options for this multiplex condition. In this review, we explore the key features of type 2 inflammation in asthma and discuss the effectiveness, safety profile, and research gaps regarding the currently approved biological therapies in asthma patients with obesity.

Anti-Allergic Inflammatory Effect of Agarum cribrosum and Its Phlorotannin Component, Trifuhalol A, against the Ovalbumin-Induced Allergic Asthma Model

Asthma is a chronic inflammatory disease involving structural changes to the respiratory system and severe immune responses mediated by allergic cytokines and pro-inflammatory mediators. Agarum cribrosum (AC) is a kind of seaweed which contains a phlorotannin, trifuhalol A. To evaluate its anti-allergic inflammatory effect against asthma, an ovalbumin inhalation-induced mouse asthma model was used. Histologic observations proved that trifuhalol A is minimizing the lung and tracheal structure changes as well as the infiltration of eosinophils and mast cells against ovalbumin inhalation challenge. From the serum and bronchoalveolar lavage fluid, ovalbumin-specific IgE and Th2-specific cytokines, IL-4, -5, and -13, were reduced with trifuhalol A treatment. In addition, IL-1β, IL-6, and TNF-α concentrations in lung homogenate were also significantly reduced via trifuhalol A treatment. Taken together, trifuhalol A, isolated from AC, was able to protect lung and airways from Th2-specific cytokine release, and IgE mediated allergic inflammation as well as the attenuation of IL-1β, IL-6, and TNF-α in lung, which results in the suppression of eosinophils and the mast cells involved asthmatic pathology.

Real-world effectiveness of omalizumab for severe allergic asthma treatment in Colombia

Background

The allergic phenotype is responsible for more than 50% of severe asthma cases. In a stepwise approach, add-on treatments such as anti-IgE are used for severe allergic asthma (SAA). This study was aimed to describe the real-world effectiveness of omalizumab in adult and pediatric patients with SAA in Colombia.

Methods

This was an observational, non-interventional, retrospective study. Data from patients with SAA that received at least one month of treatment with omalizumab was obtained from medical records at eight sites in Colombia. Time-zero (t − 0) was defined as the date of initiation of omalizumab, and data was gathered for a 12-month period before t − 0 and a 12-month period after t − 0. Clinical outcomes, including exacerbations, were assessed at 6 and 12 months. Effectiveness of omalizumab was evaluated in terms of the reduction of the risk of exacerbations (annualized rate).

Results

We included 143 patients with SAA. There was a decrease of 72.4% of the annualized rate of clinically significant asthma exacerbations during the year after omalizumab (from 1.74 before to 0.48 after) with a substantial reduction of the risk of exacerbations by 56.7% (RR [95% CI] 0.43 [0.30–0.63] p < 0,001).

Conclusion

The use of omalizumab in Colombia as a treatment for SAA notably reduced the risk of clinically significant exacerbations. This study is the first to evaluate omalizumab real-life effectiveness in pediatric and adult patients in the country.

Maternal gestational Bifidobacterium bifidum TMC3115 treatment shapes construction of offspring gut microbiota and development of immune system and induces immune tolerance to food allergen

In this study we aimed to determine whether treatment with maternal Bifidobacterium bifidum TMC3115 could affect the composition of the gut microbiota and the development of the immune system and intestinal tract of offspring, and protect the offspring from IgE-mediated allergic disease. Pregnant BALB/c mice were gavaged with TMC3115 until delivery. Offspring were sensitized with ovalbumin from postnatal days 21 to 49. After maternal treatment with TMC3115, the microbiota of the offspring’s feces, intestinal contents, and stomach contents (a proxy for breast milk) at the newborn and weaning stages exhibited the most change, and levels of immunoglobulin in the sera and stomach contents and of splenic cytokines, as well as the mRNA levels of colonic intestinal development indicators were all significantly altered in offspring at different stages. After sensitization with ovalbumin, there were no significant changes in the levels of serum IgE or ovalbumin-specific IgE/IgG1 in the TMC3115 group; however, IgM, the expression of intestinal development indicators, and the production of fecal short chain fatty acid (SCFA) were significantly increased, as were the relative abundances of Lactobacillus and the Lachnospiraceae NK4A136 group. Our results suggested that maternal treatment with TMC3115 could have a profound modulatory effect on the composition of the gut microbiota and the development of the immune system and intestinal tissue in offspring at different stages of development, and may induce immune tolerance to allergens in ovalbumin-stimulated offspring by modulating the gut microbiota and SCFA production.

Critical evaluation of asthma biomarkers in clinical practice

The advent of personalized medicine has revolutionized the whole approach to the management of asthma, representing the essential basis for future developments. The cornerstones of personalized medicine are the highest precision in diagnosis, individualized prediction of disease evolution, and patient-tailored treatment. To this aim, enormous efforts have been established to discover biomarkers able to predict patients' phenotypes according to clinical, functional, and bio-humoral traits. Biomarkers are objectively measured characteristics used as indicators of biological or pathogenic processes or clinical responses to specific therapeutic interventions. The diagnosis of type-2 asthma, prediction of response to type-2 targeted treatments, and evaluation of the risk of exacerbation and lung function impairment have been associated with biomarkers detectable either in peripheral blood or in airway samples. The surrogate nature of serum biomarkers, set up to be less invasive than sputum analysis or bronchial biopsies, has shown several limits concerning their clinical applicability. Routinely used biomarkers, like peripheral eosinophilia, total IgE, or exhaled nitric oxide, result, even when combined, to be not completely satisfactory in segregating different type-2 asthma phenotypes, particularly in the context of severe asthma where the choice among different biologics is compelling. Moreover, the type-2 low fraction of patients is not only an orphan of biological treatments but is at risk of being misdiagnosed due to the low negative predictive value of type-2 high biomarkers. Sputum inflammatory cell analysis, considered the highest specific biomarker in discriminating eosinophilic inflammation in asthma, and therefore elected as the gold standard in clinical trials and research models, demonstrated many limits in clinical applicability. Many factors may influence the measure of these biomarkers, such as corticosteroid intake, comorbidities, and environmental exposures or habits. Not least, biomarkers variability over time is a confounding factor leading to wrong clinical choices. In this narrative review, we try to explore many aspects concerning the role of routinely used biomarkers in asthma, applying a critical view over the "state of the art" and contemporarily offering an overview of the most recent evidence in this field.

Association of household air pollution with cellular and humoral immune responses among women in rural Bangladesh

Household air pollution (HAP) arising from combustion of biomass fuel (BMF) is a leading cause of morbidity and mortality in low-income countries. Air pollution may stimulate pro-inflammatory responses by activating diverse immune cells and cyto/chemokine expression, thereby contributing to diseases. We aimed to study cellular immune responses among women chronically exposed to HAP through use of BMF for domestic cooking. Among 200 healthy, non-smoking women in rural Bangladesh, we assessed exposure to HAP by measuring particulate matter 2.5 (PM2.5), black carbon (BC) and carbon monoxide (CO), through use of personal monitors RTI MicroPEM™ and Lascar CO logger respectively, for 48 h. Blood samples were collected following HAP exposure assessment and were analyzed for immunoprofiling by flow cytometry, plasma IgE by immunoassay analyzer and cyto/chemokine response from monocyte-derived-macrophages (MDM) and -dendritic cells (MDDC) by multiplex immunoassay. In multivariate linear regression model, a doubling of PM2.5 was associated with small increments in immature/early B cells (CD19+CD38+) and plasmablasts (CD19+CD38+CD27+). In contrast, a doubling of CO was associated with 1.20% reduction in CD19+ B lymphocytes (95% confidence interval (CI) = -2.36, -0.01). A doubling of PM2.5 and BC each was associated with 3.12% (95%CI = -5.85, -0.38) and 4.07% (95%CI = -7.96, -0.17) decrements in memory B cells (CD19+CD27+), respectively. Exposure to CO was associated with increased plasma IgE levels (beta(β) = 240.4, 95%CI = 3.06, 477.8). PM2.5 and CO exposure was associated with increased MDM production of CXCL10 (β = 12287, 95%CI = 1038, 23536) and CCL5 (β = 835.7, 95%CI = 95.5, 1576), respectively. Conversely, BC exposure was associated with reduction in MDDC-produced CCL5 (β = -3583, 95%CI = -6358, -807.8) and TNF-α (β = -15521, 95%CI = -28968, -2074). Our findings suggest that chronic HAP exposure through BMF use adversely affects proportions of B lymphocytes, particularly memory B cells, plasma IgE levels and functions of antigen presenting cells in rural women.

Comorbidity of ADHD and allergic diseases in early adolescence: The role of parental smoking at home

A growing body of research suggests an association between attention deficit hyperactivity disorder (ADHD) and allergic disorders, but little work has been done to explore the role of external factors such as parental smoking at home in the development of comorbid ADHD and allergic disorders. This study aimed to examine the association between allergic diseases and ADHD adjusted for exposure to parental smoking at home in early adolescents. We recruited 250 male (41.7%) and 350 female (58.3%) adolescents (mean [SD] age, 13.29 [0.52] years) via chain-referral sampling. Their ADHD symptoms were assessed by the parent proxy-report version of the Chinese Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviours (SWAN) rating scale. Data on the participants' history of clinician-diagnosed allergic diseases, family socio-demographics, and parental smoking habit were collected using a parent-completed questionnaire. Regression analyses were performed to examine the associations of interest. The levels of ADHD symptoms were comparable between allergic and non-allergic participants after controlling for child and family demographics and parental smoking at home. Notably, the risk of probable ADHD was particularly high in participants with food allergies (odd ratio = 4.51, p = 0.011) but not in those with allergic rhinitis after adjusting for parental smoking at home. Our findings suggest that second-hand smoke exposure at home is a potential risk factor underlying the link between ADHD and allergic diseases. Current management guidelines should emphasize the importance of early identification and cessation of tobacco smoke exposure for prevention of comorbidity of ADHD and allergic disorders. Clinical Trial Registration (if any): NA.

An Omalizumab Biobetter Antibody With Improved Stability and Efficacy for the Treatment of Allergic Diseases

The critical role of IgE in allergic diseases is well-documented and clinically proven. Omalizumab, a humanized anti-IgE antibody, was the first approved antibody for the treatment of allergic diseases. Nevertheless, omalizumab still has some limitations, such as product instability and dosage restriction in clinical application. In this study, we attempted to develop an omalizumab biobetter antibody with the potential to overcome its limitations. We removed two aspartic acid isomerization hotspots in CDRs of omalizumab to improve antibody candidate’s stability. Meanwhile, several murine amino acids in the framework region of omalizumab were replaced with human source to reduce the potential immunogenicity. Yeast display technology was then applied to screen antibody candidates with high binding affinity to IgE. Moreover, YTE mutation in Fc fragment was introduced into the candidates for extending their serum half-life. A lead candidate, AB1904Am15, was screened out, which showed desired biophysical properties and improved stability, high binding affinity and elevated potency in vitro, prolonged half-life in human FcRn transgenic mouse, and enhanced in vivo efficacy in cynomolgus monkey asthma model. Overall, our study developed a biobetter antibody of omalizumab, AB1904Am15, which has the potential to show improved clinical benefit in the treatment of allergic diseases.

Needs for Systems Approaches to Better Treat Individuals With Severe Asthma: Predicting Phenotypes and Responses to Treatments

Asthma is a frequent heterogeneous multifactorial chronic disease whose severe forms remain largely uncontrolled despite the availability of many drugs and educational therapy. Several phenotypes and endotypes of severe asthma have been described over the last two decades. Typical type-2-immunity-driven asthma remains the most frequent phenotype, and several targeted therapies have been developed and are now available. On the contrary, non-type-2 immunity-driven severe asthma is less understood and still requires efficient innovative therapies. A personalized approach would allow improving asthma control with the help of robust biomarkers able to predict phenotypes/endotypes, exacerbations, response to targeted treatments and, in the future, possible curative options. Some data from large multicenter cohorts have emerged in recent years, especially in transcriptomics. These data have to be integrated and reproduced longitudinally to provide a systems approach for asthma care. In this focused review, the needs for such an approach and the available data will be reviewed as well as the next steps for achieving personalized medicine in asthma.

Bee Venom Alleviates Atopic Dermatitis Symptoms through the Upregulation of Decay-Accelerating Factor (DAF/CD55)

Bee venom (BV)—a complex mixture of peptides and toxic proteins including phospholipase A2 and melittin—promotes blood clotting. In this study, we investigated the anti-atopic properties of BV and the mechanism associated with its regulation of the complement system. BV treatment upregulated the mRNA and protein levels of CD55 in THP-1 cells. Further experiments revealed that the phosphorylation of ERK was associated with upregulation of CD55. A complement-dependent cytotoxicity assay and a bacteria-killing assay showed that BV inactivated the complement system through the induction of CD55. The serum levels of C3 convertase (C3C) and Membrane attack complex (MAC) increased, while CD55 decreased in mice with AD-like lesions from DNCB treatment. However, the levels were inverted when the AD-like mice were treated with BV using subcutaneous injection, and we observed that the AD symptoms were alleviated. BV is often used to treat AD but its mechanism has not been elucidated. Here, we suggest that BV alleviates AD through the inactivation of the complement system, especially by the induction of CD55.

Omalizumab for Severe Asthma: Beyond Allergic Asthma

Different subsets of asthma patients may be recognized according to the exposure trigger and the frequency and severity of clinical signs and symptoms. Regarding the exposure trigger, generally asthma can be classified as allergic (or atopic) and nonallergic (or nonatopic). Allergic and nonallergic asthma are distinguished by the presence or absence of clinical allergic reaction and in vitro IgE response to specific aeroallergens. The mechanisms of allergic asthma have been extensively studied with major advances in the last two decades. Nonallergic asthma is characterized by its apparent independence from allergen exposure and sensitization and a higher degree of severity, but little is known regarding the underlying mechanisms. Clinically, allergic and nonallergic asthma are virtually indistinguishable in exacerbations, although exacerbation following allergen exposure is typical of allergic asthma. Although they both show several distinct clinical phenotypes and different biomarkers, there are no ideal biomarkers to stratify asthma phenotypes and guide therapy in clinical practice. Nevertheless, some biomarkers may be helpful to select subsets of atopic patients which might benefit from biologic agents, such as omalizumab. Patients with severe asthma, uncontrolled besides optimal treatment, notwithstanding nonatopic, may also benefit from omalizumab therapy, although currently there are no randomized double-blind placebo controlled clinical trials to support this suggestion. However, omalizumab discontinuation according to each patient's response to therapy and pharmacoeconomical analysis are questions that remain to be answered.

Therapeutic effects of bee venom on experimental atopic dermatitis

Atopic dermatitis (AD) is a chronic skin inflammatory disease characterized by recurrent eczema and itching. It is caused by a poorly controlled immune response and damage to the skin barrier. Purified bee venom (BV) is a natural toxin produced by honeybees (Apis mellifera L.), and is well known for its anti-inflammatory, analgesic and anti-cancer effects against various types of disease. However, treatment strategies based on anti-inflammatory properties have not been adequately studied in AD. Thus, the present study examined the progression of AD-like skin lesions induced by ovalbumin (OVA) and the mechanism of action of BV. BV, administered by intraperitoneal inoculation, was observed to reduce the symptoms of AD, in addition to the serum immunoglobulin E levels, according to dorsal skin thickness and histopathologic analysis. The treatment also inhibited the infiltration of eosinophils and mast cells. These results suggested that it is possible to develop novel AD alternative therapy using BV by effectively suppressing allergic skin inflammation in AD.

Targeted Therapy for Severe Asthma: Identifying the Right Patients

Asthma affects over 300 million people worldwide. Most asthmatics are well controlled with inhaled corticosteroids and long-acting beta-agonists; however, a proportion of patients are unresponsive and attain limited disease control. This group represents a considerable healthcare and financial burden, particularly patients who experience frequent exacerbations and require hospital admission. Development of new biological agents and disease biomarkers has provided novel avenues for treatment. These treatments have been highly successful, reducing exacerbations and yielding modest improvements in quality of life and lung function. However, only a proportion of severe asthmatics respond to this targeted treatment, highlighting the heterogeneity of severe asthma. One of the first biological therapies targeted immunoglobulin E (IgE) and demonstrated modest benefit but could only be used in a subgroup of patients. Recent research has shown that treatment aimed at the T helper-2-(Th₂)-high pathways and cytokines such as interleukin (IL)-5, IL-4, and IL-13 may also be effective in another partially overlapping subgroup. A blood eosinophil count over a defined threshold (generally ≥300 cells/μl) was a reliable biomarker and identified the majority of responders in this group. Further discovery and validation of biological markers to define asthmatic phenotypes that may benefit from biological treatments remain an area of intense interest and research. We review the latest information pertaining to biological agents and demonstrate how patient responders may potentially be identified for treatment.

Biological characteristics of intestinal IgE and gut diseases

Immunoglobulin E (IgE), a crucial protective substance for the intestinal tract, plays an important role in gut immunity. IgE is secreted by plasma cells in the submucosal lamina propria upon antigenic invasion and, together with certain cytokines and immune cells, is involved in the regulation of gastrointestinal immunity in normal or abnormal conditions via the high affinity IgE receptor (FcεR I) and low affinity IgE receptor (CD23⁺). In this paper, we review the structure, synthetic transport, secretory regulation, receptor classification, and function of intestinal IgE as well as the related gut diseases.

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.

Targeted therapy in severe asthma today: focus on immunoglobulin E

Asthma is a complex chronic inflammatory disease of multifactorial etiology. International guidelines increasingly recognize that a standard "one size fits all" approach is no longer an effective approach to achieve optimal treatment outcomes, and a number of disease phenotypes have been proposed for asthma, which has the potential to guide treatment decisions. Among the many asthma phenotypes, allergic asthma represents the widest and most easily recognized asthma phenotype, present in up to two-thirds of adults with asthma. Immunoglobulin E (IgE) production is the primary and key cause of allergic asthma leading to persistent symptoms, exacerbations and a poor quality of life. Therefore, limiting IgE activity upstream could stop the entire allergic inflammation cascade in IgE-mediated allergic asthma. The anti-IgE treatment omalizumab has an accepted place in the management of severe asthma (Global Initiative for Asthma [GINA] step 5) and represents the first (and, currently, only) targeted therapy with a specific target in severe allergic asthma. This review summarizes current knowledge of the mechanisms and pathogenesis of severe asthma, examines the actual role of IgE in asthma and the biological rationale for targeting IgE in allergic asthma and reviews the data for the efficacy and safety of omalizumab in the treatment of severe asthma. Current knowledge of the role of IgE in asthma, extensive clinical trial data and a decade of use in clinical practice has established omalizumab as a safe and effective targeted therapy for the treatment of patients with severe persistent IgE-mediated allergic asthma.

Severe Asthma: Have We Made Progress?

Tremendous efforts have been invested in research to (1) discover risk factors, biomarkers, and clinical characteristics; (2) understand the pathophysiology and treatment response variability in severe asthma; and (3) design new therapies. However, to combat severe asthma, many questions concerning the pathogenesis of severe asthma, including its natural history, genetic and environmental risk factors, and disease mechanisms, must be answered. In this article we highlight some of the major discoveries concerning the pathogenesis of severe asthma and its therapeutic development. We conclude that discoveries on numerous fronts of severe asthma, from disease heterogeneity, features of airway remodeling, cytokine mediators and signaling pathways underlying disease pathogenesis, disease mechanisms, potential biomarkers, to new therapeutic targets, demonstrate that progress has been made in understanding and developing more effective treatments for this difficult-to-treat disease.

A review of omalizumab for the management of severe asthma

Despite the expansion of the understanding in asthma pathophysiology and the continual advances in disease management, a small subgroup of patients remain partially controlled or refractory to standard treatments. Upon the identification of immunoglobulin E and other inflammatory mediators, investigations and developments of targeted agents have thrived. Omalizumab is a humanized monoclonal antibody that specifically targets the circulating immunoglobulin E, which in turn impedes and reduces subsequent releases of the proinflammatory mediators. In the past decade, omalizumab has been proven to be efficacious and well-tolerated in the treatment of moderate-to-severe asthma in both trials and real-life studies, most notably in reducing exacerbation rates and corticosteroid use. While growing evidence has demonstrated that omalizumab may be potentially beneficial in treating other allergic diseases, its indication remains confined to treating severe allergic asthma and chronic idiopathic urticaria. Future efforts may be focused on determining the optimal length of omalizumab treatment, seeking biomarkers that could better predict treatment response, as well as extending its indications.

IgE mediated sensitisation to aeroallergens in an asthmatic cohort: relationship with inflammatory phenotypes and disease severity

BACKGROUND

Atopy is known to play an important role in the asthmatic disease. The main objective of this study was to evaluate the frequency of sensitisation to common aeroallergens in a cohort of asthmatics with different inflammatory phenotypes and disease severity.

METHODS

We have conducted a retrospective cross-sectional study including 772 asthmatics recruited between 2003 and 2014 in our Asthma Clinic. The patients were defined as asthmatics on the basis of respiratory symptoms together with a positive methacholine test (PC20M) < 16 mg/ml and/or a reversibility to short-acting β2-agonists (salbutamol) ≥ 12% and 200 ml. Sensitisation to house dust mites, grass and birch pollens, cats, dogs and moulds was assessed by RAST and a specific immunoglobulin E (IgE) > 0.35 kU/l was considered as significant. Inflammatory phenotypes were subdivided between pauci-granulocytic (n = 309) (40%), eosinophilic (n = 311) (40%), neutrophilic (N = 134) (17%) and mixed-granulocytic (N = 18) (3%) asthmatics. Severe asthmatics (n = 118) were defined according to the American Thoracic Society (ATS 2000) criteria and compared with mild-to-moderate asthmatics (N = 654).

RESULTS

The eosinophilic phenotype was associated with higher levels of total serum IgE compared with neutrophilic and pauci-granulocytic asthma (p < 0.001 for both). Sensitisation rate to dogs and cats was higher in eosinophilic asthmatics (31% and 37%, respectively, p < 0.01 both) compared with neutrophilic (18% and 23% respectively) and pauci-granulocytic asthmatics (20% and 24%, respectively), while sensitisation rate to house dust mites and moulds were rather similar between the groups (ranging from 33% to 40% and from 10% to 16%, respectively). Severe asthmatics had slightly increased total serum IgE compared with mild-to-moderate asthmatics (p < 0.05) without any difference in the sensitisation rate to common aeroallergens.

CONCLUSION

Eosinophilic asthma exhibits higher total serum IgE and sensitisation rate towards animal dander while clinical severity, though also associated with higher total IgE, did not preferentially relate to any type of common aeroallergens.

P2X7 receptors induce degranulation in human mast cells

Mast cells play important roles in host defence against pathogens, as well as being a key effector cell in diseases with an allergic basis such as asthma and an increasing list of other chronic inflammatory conditions. Mast cells initiate immune responses through the release of newly synthesised eicosanoids and the secretion of pre-formed mediators such as histamine which they store in specialised granules. Calcium plays a key role in regulating both the synthesis and secretion of mast-cell-derived mediators, with influx across the membrane, in particular, being necessary for degranulation. This raises the possibility that calcium influx through P2X receptors may lead to antigen-independent secretion of histamine and other granule-derived mediators from human mast cells. Here we show that activation of P2X7 receptors with both ATP and BzATP induces robust calcium rises in human mast cells and triggers their degranulation; both effects are blocked by the P2X7 antagonist AZ11645373, or the removal of calcium from the extracellular medium. Activation of P2X1 receptors with αβmeATP also induces calcium influx in human mast cells, which is significantly reduced by both PPADS and NF 449. P2X1 receptor activation, however, does not trigger degranulation. The results indicate that P2X7 receptors may play a significant role in contributing to the unwanted activation of mast cells in chronic inflammatory conditions where extracellular ATP levels are elevated.

Mast cell stabilisers

Mast cells play a critical role in type 1 hypersensitivity reactions. Indeed, mast cell mediators are implicated in many different conditions including allergic rhinitis, conjunctivitis, asthma, psoriasis, mastocytosis and the progression of many different cancers. Thus, there is intense interest in the development of agents which prevent mast cell mediator release or which inhibit the actions of such mediators once released into the environment of the cell. Much progress into the design of new agents has been made since the initial discovery of the mast cell stabilising properties of khellin from Ammi visnaga and the clinical approval of cromolyn sodium. This review critically examines the progress that has been made in the intervening years from the design of new agents that target a specific signalling event in the mast cell degranulation pathway to those agents which have been developed where the precise mechanism of action remains elusive. Particular emphasis is also placed on clinically used drugs for other indications that stabilise mast cells and how this additional action may be harnessed for their clinical use in disease processes where mast cells are implicated.

Omalizumab for severe asthma: efficacy beyond the atopic patient?

Several years ago, omalizumab became commercially available for the treatment of severe asthma. It remains the only monoclonal antibody to be marketed for this purpose. Since then, many studies have been published endorsing its efficacy and effectiveness. Concomitantly, evidence of an overlap between atopic and non-atopic severe asthma has emerged. However, there also appears to be some disagreement regarding the value of omalizumab in the management of non-atopic disease, as some studies have failed to show any benefit in these patients. The recent literature has also sought to identify appropriate prognostic biomarkers for the use of omalizumab, other than immunoglobulin (IgE) levels. This article briefly summarizes the evolution of asthma treatment, the pathophysiology of the condition, and the method of action of omalizumab. The author describes the controlled and uncontrolled studies (also named "real-life studies") published in adult and pediatric populations in different countries and expresses his view on the current place of the drug in the management of severe allergic asthma. He offers a personal perspective on the recent evidence for the use of omalizumab in non-atopic patients, highlighting the implications for current clinical practice and the gaps in our knowledge. The author justifies his belief that omalizumab is not only an IgE-blocking drug and should be considered as a disease-modifying therapy because of its multiple effects on different biologic pathways. Finally, some areas for future research are indicated.

Anti-allergic rhinitis effect of caffeoylxanthiazonoside isolated from fruits of Xanthium strumarium L. in rodent animals

The fruits of Xanthium strumarium L. (Asteraceae) have been used extensively in China for treatment of various diseases such as allergic rhinitis (AR), tympanitis, urticaria and arthritis or ozena. This study was designed to systemically investigate the effects of the caffeoylxanthiazonoside (CXT) isolated from fruits of X. strumarium on AR in rodent animals. Animals were orally administered with CXT. Anti-allergic activity of CXT was evaluated by passive cutaneous anaphylaxis test (PCA); acetic acid-induced writhing tests were used to evaluate the analgesic effects of CXT; acetic acid-induced vascular permeability tests were performed to evaluate anti-inflammatory effect of CXT. Then, the model AR in rats was established to evaluate the effects of CXT on AR with the following tests: the sneezing and nasal scratching frequencies, IgE level in serum, and histopathological examinations. Our results demonstrated that CXT had favorable anti-allergic, anti-inflammatory and analgesic effects. Additionally, we found that CXT was helpful to ameliorate the nasal symptoms and to down-regulate IgE levels in AR rats. Thus, we suggested that CXT can be treated as a candidate for treating AR.

Successful Withdrawal of Omalizumab in a Patient with Severe Asthma: Free IgE as a Possible Biomonitor

To date, the pharmacological activity and clinical benefits of omalizumab have been well described, however several questions still remain unanswered, such as the moment to withdraw the drug as well as the possible biological markers that may be useful to do so. In the present case report, we describe our experience with our dose-reduction protocol in a middle-aged patient and elucidate the usefulness of free IgE levels.

Chemokine-like factor 1 (CLFK1) is over-expressed in patients with atopic dermatitis

Background: Human chemokine-like factor 1 (CKLF1), a recently discovered chemokine, has a broad spectrum of biological functions in immune-mediated diseases. It is highly expressed on Th2 lymphocytes and is a functional ligand for human CCR4. CKLF1 has a major role in the recruitment and activation of leucocytes, which plays an important role in the pathogenesis of allergic diseases. The present study was designed to determine the expression of CKLF1 in skin and serum in patients with atopic dermatitis (AD).

Methods: The CKLF1 protein expression in skin lesion was analyzed by immunohistochemistry and ELISA. The mRNA expression of CKLF1 in skin lesion was detected by Real-time PCR. The serum levels of CKLF1, IgE, eotaxin, IL-4, IL-5, and IL-13 were measured by ELISA.

Results: Histopathological changes in the skin of AD patients showed local inflammation with epidermal thickening and significant inflammatory cellular infiltration. Immunohistochemistry results demonstrated that CKLF1-staining positive cells were located in the epidermal and dermis, and that the CKLF1 expression in AD patients was significantly higher than that in normal control. The CKLF1 mRNA expression in AD patients was significantly higher than that in healthy controls. Serum CKLF1 and IgE levels were significantly increased in AD patients, as were the serum levels of IL-4, IL-5, IL-13 and eotaxin.

Conclusions: Both CKLF1 protien and mRNA levels are overexpressed in the skin lesion of AD patients, along with an increase in serum CKLF1 level, indicating that CKLF1 may play an important role in the development of atopic dermatitis.

Graptopetalum paraguayense Ameliorates Airway Inflammation and Allergy in Ovalbumin- (OVA-) Sensitized BALB/C Mice by Inhibiting Th2 Signal

Role of inflammation-induced oxidative stress in the pathogenesis and progression of chronic inflammatory airways diseases has received increasing attention in recent years. Nuclear factor erythroid 2-related factor 2 is the primary transcription factor that regulates the expression of antioxidant and detoxifying enzymes. Graptopetalum paraguayense E. Walther, a vegetable consumed in Taiwan, has been used in folk medicine for protection against liver injury through elevating antioxidation. Recently, we found that gallic acid is an active compound of Graptopetalum paraguayense E. Walther, which has been reported to inhibit T-helper 2 cytokines. Currently, we assumed that Graptopetalum paraguayense E. Walther may potentially protect against ovalbumin-induced allergy and airway inflammation. Results demonstrated that Graptopetalum paraguayense E. Walther ethanolic extracts (GPE) clearly inhibited airway inflammation, mucus cell hyperplasia, and eosinophilia in OVA-challenged mice. Additionally, GPE also prevented T-cell infiltration and Th2 cytokines, including interleukin- (IL-)4, IL-5, and IL-13 generations in bronchial alveolar lavage fluid. The adhesion molecules ICAM-1 and VCAM-1 were substantially reduced by GPE treatment mediated by Nrf2 activation. Moreover, GPE attenuated GATA3 expression and inhibited Th2 signals of the T cells. These findings suggested that GPE ameliorated the development of airway inflammation through immune regulation.

An engineered disulfide bond reversibly traps the IgE-Fc3-4 in a closed, nonreceptor binding conformation

IgE antibodies interact with the high affinity IgE Fc receptor, FcεRI, and activate inflammatory pathways associated with the allergic response. The IgE-Fc region, comprising the C-terminal domains of the IgE heavy chain, binds FcεRI and can adopt different conformations ranging from a closed form incompatible with receptor binding to an open, receptor-bound state. A number of intermediate states are also observed in different IgE-Fc crystal forms. To further explore this apparent IgE-Fc conformational flexibility and to potentially trap a closed, inactive state, we generated a series of disulfide bond mutants. Here we describe the structure and biochemical properties of an IgE-Fc mutant that is trapped in the closed, non-receptor binding state via an engineered disulfide at residue 335 (Cys-335). Reduction of the disulfide at Cys-335 restores the ability of IgE-Fc to bind to its high affinity receptor, FcεRIα. The structure of the Cys-335 mutant shows that its conformation is within the range of previously observed, closed form IgE-Fc structures and that it retains the hydrophobic pocket found in the hinge region of the closed conformation. Locking the IgE-Fc into the closed state with the Cys-335 mutation does not affect binding of two other IgE-Fc ligands, omalizumab and DARPin E2_79, demonstrating selective blocking of the high affinity receptor binding.

An update on anti-allergic patents granted in China: 2009 - 2011

INTRODUCTION

The prevalence of allergic diseases has increased dramatically in recent decades. Therefore, there is a pressing need for the development of effective anti-allergic services worldwide.

AREAS COVERED

In previous studies, the authors had analyzed a total of 789 anti-allergic patents granted in China from 1988 to 2008. Herein, they report a further 151 anti-allergic patents issued in China during 2009 - 2011. The current analysis covers the scientific progress in supporting anti-allergic patent applications and granted patent literature, in China, for the last 3 years.

EXPERT OPINION

The 151 anti-allergic patents granted from 2009 to 2011 mainly focus on seven types of products. They are: traditional Chinese medicines (TCM), plant extracts, biological products, synthetic compounds, pharmaceutical preparations, medical apparatus and new treatment modalities. Although the overall number of anti-allergic patent applications made between 2009 and 2011 in China is less than that of the USA and Europe, patents on TCM have increased. This suggests that there are demands for modernization of TCMs. Recently, studies of interesting new immunomodulators have also been conducted, and some of these are likely to represent clinically useful advances. In the last 3 years, several patents on these novel potential drugs have also been granted in China. The large number of anti-allergic patents issued in China, in recent times, suggests that the Chinese market is relatively competitive one that will help pharmaceutical companies make proper decisions for their research and development strategies.

Alleviation of murine allergic rhinitis by C19, a C-terminal peptide of chemokine-like factor 1 (CKLF1)

Human chemokine-like factor (CKLF1) is a human cytokine that exhibits chemotactic activities on a wide spectrum of leukocytes. One of CKLF1's C-terminal peptides, C19, exerts inhibitory effects on chemotaxis mediated by mouse Ccr3 and Ccr4 and human CCR3 and CCR4. Mouse models of asthma show that C19 can also inhibit the Th2 response. CCR3 and CCR4 are chemokine receptors important to allergic rhinitis, a condition whose pathogenesis is similar to that of asthma. Here, we established a mouse model of allergic rhinitis by repetitive sensitization and intranasal challenge with OVA and assessed whether C19 has therapeutic effects on this model. In this study, both intranasal and intraperitoneal administration of C19 reduced allergic symptoms such as sneezing and rubbing and serum concentration of IgE. C19 showed a strong ability to suppress eosinophil accumulation in nasal mucosa and lung tissues. C19 was able to suppress the Th2 cytokine IL-4 without augmenting the Th1 cytokine IFN-γ in BAL and IL-4(+) cells in the local nasal tissue. In terms of symptom amelioration, IgE reduction, and eosinophilia suppression, C19 was found to be as effective against allergic rhinitis as Budesonide. Moreover, intranasal treatment has a stronger therapeutic effect than other types of administration, and it may be more convenient and safe. For these reasons, C19 may have potential in the treatment of allergic rhinitis.

Monoclonal antibodies for the treatment of asthma

Asthma is a chronic inflammatory disease of the airways which can have a detrimental effect on quality of life and in extreme cases cause death. Although the majority of patients can control their asthma symptoms with a combination of steroids and beta agonists there is still a group of patients whose asthma remains symptomatic despite the best available treatment. These severe asthmatic patients represent the unmet medical need in asthma and are the focus of those developing novel monoclonal antibody based drugs. The complex networks of cytokines and cells involved in the pathology of asthma provide plenty of scope for intervention with monoclonal antibody based drugs which are able to block cytokine or chemokine receptor interactions, deplete cells expressing a specific receptor or block cell/cell interactions. At present anti-IgE (Xolair©) is the only monoclonal antibody based drug approved for the treatment of asthma. However, a number of other antibody based drugs have been clinically tested in asthma including anti-IL-5, anti-IL-4, anti-IL-13, anti-TNFα, anti-CCR3, anti-CCR4 and anti-OX40L. This review will examine the development of these monoclonal antibody based therapies. Since many of these therapies have targeted key pathways in asthma pathology these studies provide information on patient stratification and asthma pathology.

Anti-inflammatory effects of ethanolic extract from Lagerstroemia indica on airway inflammation in mice

AIM OF THE STUDY

In the present study, we investigated whether the Lagerstroemia indica Linn (LI) extract has an anti-inflammatory effect on lung inflammation in ovalbumin-induced asthmatic mice.

MATERIALS AND METHODS

The LI extract was obtained from dried and powdered whole plants of LI using 80% ethanol. ELISA was performed to evaluate cytokine concentration. BALB/c mice were used as a mouse model of asthma after asthmatic induction by ovalbumin sensitization and inhalation. We examined the effects of the LI extract on leukocyte infiltration and mucus secretion using cell count and histological stain.

RESULTS

The amount of cytokines, such as interleukin (IL)-2, IL-4, IL-5, IL-13, and TNF-α, was increased in Jurkat cells using the extract from house dust mites. Increased cytokine concentrations were inhibited by the LI extract. The LI extract suppressed the increased expression of IL-6 after treatment with mite extract of EoL-1 cells and THP-1 cells. In an in vivo experiment using asthmatic mice, the LI extract significantly inhibited leukocytosis and eosinophilia in bronchoalveolar lavage (BAL) fluid and lung tissue samples. The LI extract inhibited the increase in mucus secretion by goblet cells, blocked the production of reactive oxygen species in BAL fluid cells, and blocked the protein expression of IL-5 in BAL fluid. The concentration of ovalbumin-specific IgE in BAL fluid was weakly inhibited by the LI extract.

CONCLUSIONS

These results suggest that the LI extract may be used as a valuable agent for treating allergic diseases such as asthma due to its anti-inflammatory property.

Fucoidan suppresses IgE production in peripheral blood mononuclear cells from patients with atopic dermatitis

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production in B cells from mice spleen in vitro and ovalbumin-sensitized mice in vivo. In this study, we examined the effect of fucoidan on IgE production in human peripheral blood mononuclear cells (PBMC) in vitro. PBMC, obtained from healthy donors or patients with atopic dermatitis (AD) with high levels of serum IgE, were cultured with IL-4 and anti-CD40 antibody in the presence or absence of fucoidan. Fucoidan significantly reduced IgE production in PBMC without affecting cell proliferation and IFN-γ production. Fucoidan also inhibited immunoglobulin germline transcripts of B cells in PBMC, and decreased the number of IgE-secreting cells. The inhibitory effects of fucoidan were similarly observed for both PBMC from patients with AD and those with healthy donors. Our findings indicate that fucoidan suppresses IgE induction by inhibiting immunoglobulin class-switching to IgE in human B cells, even after the onset of AD.

Development and characterization of a novel anti-IgE monoclonal antibody

IgE is the central macromolecular mediator responsible for the progression of allergic reactions. Omalizumab (Xolair) is a humanized monoclonal anti-IgE antibody directed at the FcepsilonRI-binding domain of human IgE, which represents a novel therapeutic approach in the management of asthma. In this study, we developed a monoclonal antibody (7A5) against human IgE via hybridoma technique. Our data showed that 7A5 could inhibit free IgE molecules to bind to receptors without affecting IgE already bound to cellular receptors. Importantly, 7A5 was able to inhibit IgE-induced histamine release of basophilic leukemia cells. Next, the phage display peptide library technology was employed to select peptides binding to 7A5 and a striking peptide sequence motif was recovered, which is homologous to the sequence (391)KQR(393) within the Cepsilon3 domain of IgE-Fc, Our results further indicated that 7A5 specifically bound to the synthesized peptide "(388)KEEKQRN(394)" containing the (391)KQR(393) motif in IgE-Fc. The epitope of 7A5 was found to be spatially close to the FcepsilonRI-binding site, suggesting that 7A5 binding to IgE might block IgE binding to receptors via steric hindrance. The anti-IgE monoclonal antibody 7A5 may have the potential to be developed as a therapeutic agent for the treatment of allergic diseases.

Bambusae Caulis in Taeniam extract reduces ovalbumin-induced airway inflammation and T helper 2 responses in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Bambusae Caulis in Taeniam (BC) was known as traditional herbal medicine with anti-inflammatory property in the Orient.

AIM OF THE STUDY

Allergic asthma is inflammatory disease of airways associated with enhanced T helper (Th) 2 lymphocytes responses to allergens, leading to eosinophilic infiltration and elevated serum IgE levels. Although there were some studies that BC extract had an anti-inflammatory property, there was no study on asthma. In present study, we investigated the suitability of BC extract as a therapeutic candidate in the treatment of allergic airway disease in ovalbumin-induced asthma model.

MATERIALS AND METHODS

Balb/C mice (female, 6 weeks old) were treated by ovalbumin sensitization and nebulization, and used as asthma model. The number of eosinophil in bronchoalveolar lavage (BAL) fluid and the degree of eosinophila were investigated by hematoxylin and eosin stain and the infiltration of inflammatory cells into lung tissues was examined by staining by hematoxylin and eosin solution. The levels of interleukin (IL)-4 in BAL fluid, immunoglobulin E (IgE) in serum, interferon (IFN)-gamma and IL-4 production in splenocyte culture from Balb/C mice (not treated, 6 weeks old) that incubated with or without BC extract for 48 h were determined by enzyme-linked immunosorbent assay.

RESULTS

The level of eosinophils was decreased by treatment of the animals with BC extract (40 mg/kg) and correspondingly, a significantly lowered degree of eosinophila was also reported (p<0.01). In lung tissue, BC extract reduced the increased immune cell infiltration induced by OVA (p<0.05). Furthermore, the levels of IL-4 and IgE in BAL fluid or serum up-regulated by OVA was decreased by BC extract. Finally, IFN-gamma production was significantly increased (p<0.01), while IL-4 production significantly decreased (p<0.01), after treatment of the culture supernatants of splenocytes with BC extract.

CONCLUSIONS

These results indicated that BC extract reduces OVA-induced airway inflammation and Th 2 response in mice, suggesting that BC extract can be a therapeutic candidate for allergic airway disease, including asthma.

IL-4-induced transcription factor NFIL3/E4BP4 controls IgE class switching

IL-4 signaling promotes IgE class switching through STAT6 activation and the induction of Ig germ-line epsilon (GLepsilon) transcription. Previously, we and others identified a transcription factor, Nfil3, as a gene induced by IL-4 stimulation in B cells. However, the precise roles of nuclear factor, IL-3-regulated (NFIL3) in IL-4 signaling are unknown. Here, we report that NFIL3 is important for IgE class switching. NFIL3-deficient mice show impaired IgE class switching, and this defect is B-cell intrinsic. The induction of GLepsilon transcripts after LPS and IL-4 stimulation is significantly reduced in NFIL3-deficient B cells. Expression of NFIL3 in NFIL3-deficient B cells restores the impairment of IgE production, and overexpression of NFIL3 in the presence of cycloheximide induces GLepsilon transcripts. Moreover, NFIL3 binds to Iepsilon promoter in vivo. Together, these results identify NFIL3 as a key regulator of IL-4-induced GLepsilon transcription in response to IL-4 and subsequent IgE class switching.

Peritoneal injection of fucoidan suppresses the increase of plasma IgE induced by OVA-sensitization

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production by B cells in vitro. In this study, we examined the effect of fucoidan on IgE production in vivo. The OVA-induced increase of plasma IgE was significantly suppressed when fucoidan was intraperitoneally, but not orally, administered prior to the first immunization with OVA. The production of IL-4 and IFN-gamma in response to OVA in spleen cells isolated from OVA-sensitized mice treated with fucoidan in vivo was lower than that from mice treated without fucoidan. Moreover, the flow cytometric analysis and ELISpot assay revealed that the administration of fucoidan suppressed a number of IgE-expressing and IgE-secreting B cells, respectively. These results indicate that fucoidan inhibits the increase of plasma IgE through the suppression of IgE-producing B cell population, and the effect of fucoidan in vivo is crucially dependent on the route and timing of its administration.

A novel (S)-(+)-decursin derivative, (S)-(+)-3-(3,4-dihydroxy-phenyl)-acrylic acid 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano[3,2-g]chromen-3-yl-ester, inhibits ovalbumin-induced lung inflammation in a mouse model of asthma

(S)-(+)-Decursin is a coumarin compound present in herbal extracts that has various biological activities. (S)-(+)-Decursin attenuates pathophysiologic progression in cancer, bacterial infection and neuropathy. Asthma is an inflammatory disease associated with increased infiltration of leukocytes, especially eosinophils, and secretion of mucus into the airways. Although (S)-(+)-decursin, as well as (S)-(+)-decursin analogues, have various pharmacological properties, the effect of these compounds on asthma is not known. In the present study, we synthesized (S)-(+)-3-(3,4-dihydroxy-phenyl)-acrylic acid 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano[3,2-g]chromen-3-yl-ester (compound 6, C6) from (S)-(+)-decursin and examined if C6 had any inhibitory effects on lung inflammation in a mouse model of ovalbumin-induced asthma. C6 significantly inhibited the leukocytosis (p < 0.01) and eosinophilia (p < 0.05) in bronchoalveolar lavage (BAL) fluid. Examination of lung tissues stained with hematoxylin and eosin and periodic acid Schiff reagents showed that C6 suppressed the increased infiltration of inflammatory cells and elevated mucus hypersecretion. Protein levels of interleukin (IL)-5 (p < 0.05) and eotaxin (p < 0.01) were significantly reduced in BAL fluid by C6. C6 also significantly reduced total and ovalbumin-specific immunoglobulin E (IgE) levels in BAL fluid (p < 0.01) as well as that in serum (p < 0.05). C6 may have pharmacological effects for asthma and may be a potent therapeutic agent for the treatment of allergic airway diseases.

Anti-allergic effects of phlorotannins on histamine release via binding inhibition between IgE and Fc epsilonRI

Two bioactive phloroglucinol derivatives, fucodiphloroethol G (1) and phlorofucofuroeckol A (3) were first isolated from Eckolonia cava (EC) and characterized by nuclear magnetic resonance (NMR) spectroscopic methods, along with eckol (2). In this study, anti-allergic activities of phloroglucinol derivatives were assessed on human basophilic leukemia (KU812) and rat basophilic leukemia (RBL-2H3) cell lines using a histamine release assay. Both compounds 1 and 3 exhibited a significant inhibitory activity against histamine release. Meanwhile, the potential inhibitory mechanism was also suggested as the suppression of binding activity between IgE and Fc epsilonRI by the cytometric analysis. These results suggested that compounds 1 and 3 could be the key effectors in the crude methanol extract of EC against allergy disease and used as novel candidates for development in the cosmetic and drug industries potentially.

Study of a BALB/c Mouse Model for Allergic Asthma

Allergic asthma is a worldwide public health problem and a major socioeconomic burden disease. It is a chronic inflammatory disease marked by airway eosinophilia and goblet cell hyperplasia with mucus hypersecretion. Mouse models have proven as a valuable tool for studying human asthma. In the present report we describe a comparison of mouse asthma models. The experiments were designed as follows: Group I was injected with ovalbumin (OVA, i.p.) on day 1 and challenged with 1% OVA (aerosol exposure) on days 14~21. Group II was injected on day 1, 14 and aerosol-immunized on days 14~21. Group III was injected on day 1, 14 and immunized by 1% OVA aerosol on days 18~21. We assessed asthma induction by determining the total number of white blood cells (WBC) and eosinophils as well as by measuring cytokine levels in bronchoalveolar lavage fluid (BALF). In addition, we evaluated the histopathological changes of the lungs and determined the concentration of immunoglobulin E (IgE) in serum. Total WBC, eosinophils, Th2 cytokines (IL-4, IL-13) and IgE were significantly increased in group I relative to the other groups. Moreover, histopathological studies show that group I mice show an increase in the infiltration of inflammatory cell-in peribronchial and perivascular areas as well as an overall increase in the number of mucus-containing goblet cells relative to other groups. These data suggest that group I can be a useful model for the study of human asthma pathobiology and the evaluation of existing and novel therapeutic agents.

Inhibitory effects of Duchesnea chrysantha extract on ovalbumin-induced lung inflammation in a mouse model of asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Duchesnea chrysantha (D. chrysantha) is a herb with anti-oxidative, anti-inflammatory and immune-enhancing properties.

AIM OF THE STUDY

Asthma is an inflammatory disease of the lungs, and the hallmarks of the disease are increased inflammatory cell infiltration into the airways and poor respiratory function. Although there is the possibility that D. chrysantha may have an inhibitory effect on lung inflammation, the effects of D. chrysantha on asthma have not been fully investigated. In the present study, we investigated the anti-inflammatory activity of D. chrysantha extract (Dc extract) on lung inflammation in a murine model of ovalbumin-induced asthma.

MATERIALS AND METHODS

Dc extract was obtained from dried and powdered whole plants of D. chrysantha using 80% ethanol. BALB/c mice induced by ovalbumin sensitization and nebulization were used as a mouse model of asthma. RT-PCR and ELISA were performed to measure mRNA and protein expression of cytokines. We examined the effects of Dc extract on leukocyte infiltration and mucus secretion using periodic acid-Schiff staining as well as hematoxylin and eosin staining.

RESULTS

Dc extract significantly inhibited leukocytosis and eosinophilia in the bronchoalveolar lavage (BAL) fluid (p<0.01). Dc extract significantly reduced the elevated infiltration of inflammatory cells (p<0.05) and inhibited the increased mucus secretion, despite the absence of significant value. Although Dc extract weakly inhibited the mRNA expression of IL-4, IL-5, IL-13, and eotaxin, it strongly inhibited the protein expression of IL-5 (p<0.05) and eotaxin (p<0.01) in BAL fluid. Ovalbumin-specific IgE levels in the serum and BAL fluid were blocked by Dc extract (p<0.05).

CONCLUSIONS

These results suggest the possibility that Dc extract can exert suppressive effects on asthma and may provide evidence that Dc extract is a useful agent for the treatment of allergic airway disease.

Reduction of the total IgE level by omalizumab in children and adolescents

BACKGROUND

Current data from clinical studies show that patients with severe allergic asthma experience a significant improvement from omalizumab. The early and late allergic reactions are inhibited by formation of complexes with free circulating immunoglobulin E (IgE), independent of which antigen activates the allergic cascade. The dosage of omalizumab depends on body weight and IgE level, yet no parameter has been established to guide dosage changes during therapy. The aim of this study was to investigate the value of the determination of total IgE by ADVIA Centaur assay to monitor the therapy progress.

PATIENTS AND METHODS

Nine patients, 8 to 17 years of age, received therapy with omalizumab due to severe allergic bronchial asthma. In addition, the patients had pronounced rhinoconjunctivitis, food allergy, insect sting allergy, and/or neurodermitis. The total IgE in the serum (Sandwich-Immunoassay ADVIA Centaur) was measured in the patients once monthly before each omalizumab injection as a potential progress parameter.

RESULTS

Six months after the beginning of therapy with omalizumab, a significant decrease of the total IgE concentration was found, in comparison to the baseline values (p < 0.01). In all patients, the tolerability of omalizumab was very good; there was a reduction in the frequency of the asthma exacerbations and rescue medications. The dosage of inhaled glucocorticoids could be lowered. All patients reported a clearly improved quality of life.

CONCLUSIONS

The increase of the total IgE concentrations after administration of omalizumab described in the literature could not be confirmed. The value of total serum IgE as a progress parameter should be investigated in controlled studies with regard to sensitivity and specificity of the respective assays. The establishment of a test procedure for therapeutic monitoring appears urgently necessary, so that the appropriate dosage of omalizumab is applied in children and adolescents. Patients receiving omalizumab therapy should be closely monitored.

Mechanisms of allergy and asthma

Allergies are the result of an inappropriate reaction against innocuous environmental proteins. The prevalence and severity of allergic diseases has increased dramatically during the last decade in developed countries. Allergen-specific T helper (Th) cells play a pivotal role in the pathogenesis of allergic hypersensitivity reactions. These Th cells activate a complex immune reaction that triggers the release of potent mediators and enhances the recruitment of inflammatory cells, which in turn elicit an inflammatory response that leads to the clinical symptoms of allergic disease. The current therapies for allergic diseases focus primarily on control of symptoms and suppression of inflammation, without affecting the underlying cause. However, the knowledge about the pathophysiology of allergic diseases has substantially increased, offering new opportunities for therapeutic intervention. In this review, we will focus on current insights into the mechanism of allergic reactions.

Effects of lactose-beta-sitosterol and beta-sitosterol on ovalbumin-induced lung inflammation in actively sensitized mice

Asthma is a disease marked by chronic lung inflammation and the number of patients suffering from asthma increases annually. Both beta-sitosterol (BS) and beta-sitosterol glucoside exist in a variety of plants and have anti-tumor, anti-microbial, and immunomodulatory activities. However, the precise role of BS and beta-sitosterol glucoside in asthma has not been well understood. The aim of this study was to investigate the inhibitory effects of BS and lactose-BS (L-BS) on the pathophysiological process in ovalbumin-induced asthmatic mice. The total cells and eosinophils in the bronchoalveolar lavage (BAL) fluid markedly decreased (p<0.05) after L-BS or BS administration (1 mg/kg; i.p.), and the ROS production also decreased in comparison to the asthma control. Histopathological features were detected by performing histochemistry, including H&E and alcian blue & P.A.S staining. Both L-BS and BS mitigated the inflammation by eosinophil infiltration and mucus hypersecretion by goblet hyperplasia. These effects of L-BS were superior to those of BS. L-BS and BS inhibited the increased mRNA and protein expression of IL-4 and IL-5 in the lung tissue and BAL fluid, respectively. The IgE concentration in the BAL fluid and serum was measured by performing ELISA and the ovalbumin-specific IgE in the BAL fluid was uniquely inhibited by L-BS (p<0.05). The splenocytes were isolated from the normal and asthmatic mice and incubated in the absence and presence of 100 microg/ml ovalbumin, respectively. L-BS blocked the survival rate of the splenocytes of the mice (p<0.01). This finding indicates the possibility of L-BS and BS as potential therapeutic molecules in asthma and may contribute to the need to improve current therapeutic drugs.