A murine model of allergic rhinitis: studies on the role of IgE in pathogenesis and analysis of the eosinophil influx elicited by allergen and eotaxin

Loss of SENP3 mediated the formation of nasal polyps in nasal mucosal inflammation by increasing alternative activated macrophage

BACKGROUND AND AIM

Small ubiquitin-like modifier (SUMO)-specific protease (SENP)3 is a protease molecule that responds to reactive oxygen species (ROS) with high sensitivity. However, the role of ROS and SENP3 in the formation of nasal polyps (NPs) remains unclear. This study aimed to explore how SENP3 influenced the outcome of chronic rhinosinusitis (CRS) by altering macrophage function, that is, the formation of NPs.

METHODS

The alternative activation of macrophage (M2) was detected with CD68⁺ CD206⁺ in humans and CD206⁺ in mice. The nasal mucosa of patients with CRS was tested using flow cytometry (CD68, CD80, and CD206) and triple-color immunofluorescence staining (CD68, CD206, and SENP3). The bone marrow-derived macrophages from SENP3 knockout and control mice were stimulated with interleukin (IL)-4 and IL-13 to analyze alternative macrophage polarization in vitro. An animal model of allergic rhinitis was constructed using SENP3 knockout mice. CD206 was detected by immunofluorescence staining. The thickening of eosinophil-infiltrated mucosa was detected by Luna staining.

RESULTS

The number of CD68⁺ CD206⁺ M2 increased in the nasal mucosa of patients with CRS with NP (CRSwNP) compared with patients with CRS without NP (CRSsNP), but with no significant difference between the groups. SENP3 knockout increased the polarization of F4/80⁺ CD206⁺ M2. Meanwhile, the number of CD206⁺ M2 significantly increased in the allergic rhinitis model constructed using SENP3 knockout mice and controls, with a more obvious proliferation of the nasal mucosa.

CONCLUSION

Downregulation of SENP3 promotes the formation of nasal polyps mediated by increasing alternative activated macrophage in nasal mucosal inflammation.

Visual analysis of allergic rhinitis in children based on web of science and CiteSpace software

BACKGROUND

In recent years, Allergic Rhinitis (AR) in children has caused widespread public concern. However, there are few studies concerning the overall trends in AR research in children based on bibliometric analysis.

OBJECTIVE

This study aims to explore hotspots and emerging trends in AR in children.

METHODS

The relevant publications were searched for in the Web of Science (WOS) Core Collection on December 31, 2021. The searched studies were exported to CiteSpace and Microsoft Excel for further visualized analysis.

RESULTS

In total, 649 articles were included. The number of publications related to AR in children has increased steadily in the last 20 years. Giorgio Ciprandi from Italy has the most articles and the leading countries were China and the USA. Guangzhou Medical University in China and Hallym University in Korea were the institutions with the most articles. The high-frequency keywords included AR, asthma, children, prevalence, and symptoms. Pathogenesis, comorbidity, epidemiology, symptoms, and therapy of AR in children are research hotspots.

CONCLUSION

Over the past 20 years, research on AR in children has gradually improved. Visualization analysis indicates that pathogenesis, comorbidity, epidemiology, symptoms, and therapy are research hotspots, and immunotherapy and severity are probably the main research directions.

The efficacy and safety of Chinese herbal compound in pediatric patients with allergic rhinitis: A protocol for systematic review and meta-analysis

BACKGROUND

We design this study to assess the efficacy and safety of Chinese herbal compound for allergic rhinitis in children.

METHODS

PubMed, EMbase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), WanFang, the Chongqing VIP Chinese Science and Technology Periodical Database, and China biomedical literature database (CBM) will be searched from the establishment of each database to July 2020. Randomized controlled trials of Chinese herbal compound for the treatment of allergic rhinitis in children will be included. Two researchers will screen the literature, extract data, and assess the risk of bias independently. Statistical analysis will be performed in RevMan 5.3.

RESULTS

This study will summarize high quality evidence of randomized controlled trials on exploring the efficacy and safety of Chinese herbal compound for allergic rhinitis in children.

CONCLUSIONS

The findings of study will provide scientific evidence of the efficacy and safety of Chinese herbal compound for allergic rhinitis in children for clinician and further studies.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also will not involve endangering participant rights. Ethical approval is not required. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/Q5TRZ.

5-Oxo-ETE from Nasal Epithelial Cells Upregulates Eosinophil Cation Protein by Eosinophils in Nasal Polyps in vitro

BACKGROUND

5-Oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) is a potent eosinophil chemoattractant and activator that is synthesized not only in inflammatory cells but also in bronchial epithelial cells. The purpose of this study is to clarify whether 5-oxo-ETE can promote the production of eosinophil cation protein (ECP) by eosinophils in nasal polyps (NP) in vitro, and whether normal nasal epithelial cells can produce this lipid mediator in response to oxidative stress.

MATERIALS AND METHODS

Nasal biopsy samples were obtained from normal subjects or subjects with chronic rhinosinusitis with NP. The infiltration of eosinophil in NP was detected and cultured. After that, concentrations of ECP in eosinophil and NP cultures were evaluated after the treatment of 5-oxo-ETE or 5-oxo-ETE + its receptor (OXER) antagonist, pertussis toxin (PT). Then we studied the synthesis of 5-oxo-ETE after H2O2 stimulation by normal nasal epithelial cells and by epithelial cells of NP alone in the cultures, and also determined the OXER expression in NP.

RESULTS

The number of infiltrative eosinophils in NP was increased. The ECP levels in eosinophil and NP cultures were enhanced after the administration of 5-oxo-ETE, and decreased by the PT treatment. 5-Oxo-ETE was upregulated in the cultures of nasal epithelial cells in the presence of H2O2 and of NP epithelial cells alone. The OXER was expressed in inflammatory cells, and not in epithelial cells.

CONCLUSION

5-Oxo-ETE produced by nasal epithelial cells may play a role in the formation and development of NP.

Skullcapflavone II attenuates ovalbumin-induced allergic rhinitis through the blocking of Th2 cytokine production and mast cell histamine release

Allergic rhinitis is a common heterogeneous chronic upper airway disorder and is an IgE-mediated inflammation characterized by one or more nasal symptoms such as sneezing, itching, nasal discharge, rhinorrhea, post nasal drainage and nasal blockage. In the present study, the effects of skullcapflavone II (SCFII) on upper airway inflammation, Th2 cytokines, and NF-κB signaling in an ovalbumin (OVA)-induced allergic rhinitis (AR) murine model in vivo were investigated. OVA-induced AR mice increased nasal symptoms, eosinophils and mast cells infiltration into nasal cavity, OVA-specific IgE/IgG1 and histamine in serum, Th2 cytokines including IL-13 and GATA3, and NF-κB signaling in NALF and lung homogenate. Interestingly, treatment of SCFII reduced the levels of OVA-specific IgE/IgG1 and histamine in serum, of Th2 cytokines and of NF-κB signaling in the NALF and the lung homogenate, and histopathological changes in the nasal tissue and the lung. Also, dexamethasone suppressed such increases. The results of this study suggested that SCFII may ameliorate allergic inflammation of upper airway in AR mice model by blocking the Th2 cytokine production, the NF-κB signal pathway and the mast cell histamine release. Taken together, we suggest that SCFII may be used as a therapeutic agent for patients with Th2-mediated or mast cell-mediated allergic diseases.

Etiology of Chronic Rhinosinusitis: The Role of Fungus

Chronic rhinosinusitis (CRS) is a multifactorial disease. Predisposing factors can be divided into environmental and non-host factors, such as pollution, viral infections, smoking, fungus, and bacteria; general host factors, including genetic factors and immune deficiency; and local host factors, including persistent focal inflammation within the ostiomeatal complex. Evidence suggests that the underlying bone in the ostiomeatal complex is actively involved in the disease process of CRS. The evidence concerning a broad range of predisposing factors for CRS is reviewed. Chronic rhinosinusitis is an inflammatory disorder with numerous predisposing factors, including genetics, pollution, anatomic anomalies, bacteria, and fungus. In some studies, fungi have been cultured from nearly 100% of patients with rhinosinusitis and nasal polyposis. T-cell sensitization to fungus with production of the T-helper 2 (Th2) cytokine interleukin-5 has been proposed as a key step in the initiation of the disease. Interleukin-5 also plays an important role in the effector phase of the disease through its effects on eosinophilopoesis and eosinophil survival. There is considerable controversy concerning the role of fungi as the cause of “chronic eosinophilic rhinosinusitis” and whether this even represents a distinct clinical entity. Further study is also required to define the optimal treatment for the disease.

Establishment of a new animal model of allergic rhinitis with biphasic sneezing by intranasal sensitization with Staphylococcal enterotoxin B

Allergic rhinitis (AR) is a global health problem. The effectiveness of currently available medications is limited and therefore investigation for more effective drugs is essential. The aim of the present study was to establish a model of AR in guinea pigs that can be utilized for the further investigation of new drugs. Guinea pigs were intranasally sensitized with 1 µg Staphylococcal enterotoxin B (SEB) dissolved in 40 µl saline once daily for 14 days. One week after the last sensitization, the same treatment was applied intranasally once every four days for a total of 30 times. In the treatment group, terfenadine was administered orally 70 min before the 4th, 14th and 24th challenge. Sneezing and nasal scratching were evaluated following each of the 30 challenges. The quantity of antigen-specific antibodies in the serum was measured. Between the 19th and 30th challenges, the guinea pigs in the model group produced significant biphasic elevations in sneezing number, with peaks 10 min-2 h and 4-8 h after the SEB challenges. In addition, the guinea pigs produced significantly more sneezing in the first peak during the 19th to 30th challenges than during the first to 18th challenges (P<0.01). Terfenadine significantly inhibited the early- and late-phase sneezing at all challenge times. The serum levels of SEB-specific immunoglobulin (Ig) E and IgG₁ were higher in the model group in comparison with those in the control group (P<0.01). This experiment demonstrated that SEB can induce typical AR with biphasic sneezing in guinea pigs. Histamine may play an important role in the early- and the late-phase sneezing in the model of AR. This model can be potentially used for the investigation of new drugs.

Establishment and characterization of an experimental mouse model of allergic rhinitis

Allergic rhinitis (AR) is a common worldwide disease. Animal studies on AR were adopted in various investigations. However, animal studies simply aimed at establishing an animal model for AR have been seldom seen. The purpose of this study was to introduce an easy-to-establish experimental mouse model of AR. To develop a mouse model of AR, 38 Balb/c mice were randomly assigned to two groups. Mice in the study group were sensitized by intraperitoneal (IP) injection of ovalbumin (OVA) on day 1 and 6, followed by continuous inhalation (IH) of OVA solution for 1 week (day 8-14) using a newly designed inhalation box. The control group mice received sensitization of IP normal saline and IH sterilized distilled water instead of OVA. Before and after sensitization, the frequencies of nasal symptoms (sneezing, nasal rubbing) were recorded and the serum levels of total immunoglobulin E (IgE) were evaluated using ELISA. Finally, the murine nasal mucosal tissues were stained by Giemsa solution to estimate the degree of mast cell infiltration. After sensitization by IP and IH OVA, the study group showed significant phenotypic changes including increased sneezing and rubbing. Pathological and cytological findings also confirmed significant elevated serum total IgE titer and local mast cell infiltration in the study group statistically. We successfully developed a workable experimental animal model for AR that was more easily sensitized using our new-designed inhalation box, with less stress and more precisely to be observed.

Effects of Hyeonggaeyeongyo-tang in ovalbumin-induced allergic rhinitis model

Allergic rhinitis (AR) is an allergic inflammation of the nasal airways. The prevalence of AR is increasing worldwide. We investigated whether Hyeonggaeyeongyo-tang (HYT) is effective to suppress the progression of AR induced by ovalbumin (OVA). Male BALB/c mice were used for this study. Allergic rhinitis was induced by OVA. Treatment with HYT was assessed to study the effect of HYT on allergic rhinitis in mice. Histological analysis, immunohistochemistry, multiplex cytokine assay, blood analysis, and cell viability assay were performed to verify inhibitory effect of HYT on allergic rhinitis. HYT did not show any toxicity maintaining body weight. Food intake was steady without variation in mice. HYT reduced infiltration of inflammatory cells and mast cells into nasal cavity. HYT reduced the levels of cytokines and leukocytes in the blood. HYT decreased the splenocyte cell viability. Antihistamines and steroids are the most common medications used to treat allergic rhinitis. However, long-term use of drug generates resistance or side effects requiring the development of new drug. Our present study clearly demonstrates that HYT suppresses the progression of allergic rhinitis induced by OVA. This suggests that HYT might be a useful drug for the treatment of allergic rhinitis.

Proteinase-activated receptor 2 blockade impairs CCL11- or allergen-induced eosinophil recruitment in experimental pleurisy

Although proteinase-activated receptor (PAR)-2 has been implicated in inflammatory diseases, its role in regulating eosinophil recruitment in response to chemoattractants remains unclear. Here, we investigated the role of PAR-2 and PAR-2-activating Mast Cell (MC) tryptase on chemokine C-C motif ligand (CCL)11- and antigen-induced eosinophil recruitment to the pleural cavity of BALB/c mice. The PAR-2-activating peptide H-Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SLIGRL-NH2) induced eosinophil recruitment whereas PAR-2 blockade inhibited ovalbumin (OVA)- or CCL11-induced eosinophil recruitment. Moreover, OVA and CCL11 induced PAR-2 expression in pleural leukocytes, and the MC tryptase inhibitor APC 366 ([N-(1-hydroxy-2-napthoyl)-l-arginyl-l-prolinamide hydrochloride]) abolished CCL11-induced eosinophil recruitment. These results suggest a pro inflammatory effect of PAR-2 and support a role for MC tryptase mediating eosinophil migration via PAR-2 signaling. Taken together, our results suggest that PAR-2 activation through endogenous MC tryptase activity could be required, at least partially, to mediate CCL11-induced eosinophil migration.

Induction of allergic rhinitis in mice

We describe a method for allergic rhinitis (AR) induction in mice. Methodology involves nasal infusions of small volumes of ovalbumin for both initial sensitization and challenges. The latter are frequent and carried out over several weeks. This methodology more closely resembles natural AR induction than does the common use of systemic sensitization, often with adjuvants, followed by nasal challenges with relatively large allergen volumes. Also described are methodologies for collection of cardiac blood and perfusion for preparation of histological samples, both essential in verifying AR induction in individual animals.

Concordance of preclinical and clinical pharmacology and toxicology of monoclonal antibodies and fusion proteins: soluble targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards soluble targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 14 currently approved mAbs and fusion proteins targeted to soluble targets. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions' and United States Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the following approved biopharmaceuticals were included: adalimumab, anakinra, bevacizumab, canakinumab, certolizumab pegol, denosumab, eculizumab, etanercept, golimumab, infliximab, omalizumab, ranibizumab, rilonacept and ustekinumab. Some related biopharmaceuticals in late-stage development were also included for comparison. Good concordance with human pharmacodynamics was found for both non-human primates (NHPs) receiving the human biopharmaceutical and mice receiving rodent homologues (surrogates). In contrast, there was limited concordance for human adverse effects in genetically deficient mice, mice receiving surrogates or NHPs receiving the human pharmaceutical. In summary, the results of this survey show that although both mice and NHPs have good predictive value for human pharmacodynamics, neither species have good predictive value for human adverse effects. No evidence that NHPs have superior predictive value was found.

In vivo determination of mouse olfactory mucus cation concentrations in normal and inflammatory states

OBJECTIVE

Olfaction is impaired in chronic rhinosinusitis (CRS). The study has two aims: (1) to determine whether changes in cation concentration occur in the olfactory mucus of mice with CRS, which may affect chemo-electrical transduction, (2) and to examine whether these alterations are physiologically significant in humans.

STUDY DESIGN

Animal study in mice and translational study in humans.

METHODS

Inflammation was induced by sensitization and chronic exposure of 16 C57BL/6 mice to Aspergillus fumigatus. The control group included 16 untreated mice. Ion-selective microelectrodes were used to measure free cation concentrations in the olfactory mucus of 8 mice from each treatment group, while the remaining mice were sacrificed for histology. To validate the findings in the animal model, olfactory threshold was measured in 11 healthy human participants using Sniffin' Sticks before and after nasal irrigation with solutions that were composed of either of the cation concentrations.

RESULTS

In 8 mice, olfactory mucus of chronically inflamed mice had lower [Na(+)] (84.8±4.45 mM versus 93.73±3.06 mM, p = 0.02), and higher [K(+)] (7.2±0.65 mM versus 5.7±0.20 mM, p = 0.04) than controls. No difference existed in [Ca(2+)] (0.50±0.12 mM versus 0.54±0.06 mM, p = 0.39). In humans, rinsing with solutions replicating ion concentrations of the mouse mucosa with chronic inflammation caused a significant elevation in the median olfactory threshold (9.0 to 4.8, p = 0.003) but not with the control solution (8.3 to 7.8, p = 0.75).

CONCLUSION

Chronic inflammation elevates potassium and lowers sodium ion concentration in mice olfactory mucus. Nasal irrigation with a corresponding solution induced olfactory threshold shift in humans.

Beyond immediate hypersensitivity: evolving roles for IgE antibodies in immune homeostasis and allergic diseases

Immunoglobulin E (IgE) antibodies have long been recognized as the antigen-specific triggers of allergic reactions. This review briefly introduces the established functions of IgE in immediate hypersensitivity and then focuses on emerging evidence from our own investigations as well as those of others that IgE plays important roles in protective immunity against parasites and exerts regulatory influences in the expression of its own receptors, FcεRI and CD23, as well as controlling mast cell homeostasis. We provide an overview of the multifaceted ways in which IgE antibodies contribute to the pathology of food allergy and speculate regarding potential mechanisms of action of IgE blockade.

2-Aminoethoxydiphenyl borate administration into the nostril alleviates murine allergic rhinitis

OBJECTIVE

Orai1 is the pore-forming subunit of the Ca(2+) release-activated Ca(2+) channels and plays a key role in the store-operated Ca(2+) entry. However, little is known about the function of this pathway in allergic rhinitis (AR). In this study, we examined whether the intervention of Orai1 pathway was capable of controlling IgE-mediated allergic reactions by using AR mice models.

MATERIALS AND METHODS

We used Western blotting and real-time reverse transcription polymerase chain reaction to evaluate Orai1 expression in nasal mucosa and nasal-associated lymphoid tissue (NALT) of normal, control, and 2-aminoethoxydiphenyl borate (2-APB)-treated mice. In addition, we analyzed concentrations of nasal lavage fluid leukotriene C4 (LTC4), eosinophil cation protein (ECP), ovalbumin-specific IgE, and interleukin-4 (IL-4) through enzyme-linked immunosorbent assay and measured messenger RNA (mRNA) levels of LTC4 synthase and ECP in nasal mucosa, and germline Cɛ transcription and IL-4 mRNA in NALT by using real-time reverse transcription polymerase chain reaction among groups.

RESULTS

2-Aminoethoxydiphenyl borate administration into the nostril reduced numbers of sneezing and nasal rubbing as well as counts of invasive eosinophils in treated mice compared with those in control ones. Furthermore, the administration suppressed Orai1 expression in nasal mucosa and NALT of treated mice compared with that of control ones. Similarly, 2-APB treatment restrained nasal lavage fluid LTC4, ECP, ovalbumin-specific IgE, and IL-4 and their corresponding mRNAs in the previously mentioned tissues of treated mice in comparison with those of control ones.

CONCLUSION

Our results indicate that 2-APB treatment effectively alleviates murine AR through pleiotropic activities.

Interleukin-13 receptor A1 gene polymorphism and IL-13 serum level in atopic and non-atopic Egyptian children

OBJECTIVES

To assess serum interleukin (IL) 13 levels in atopic diseases and to determine the role of IL-13R A(1) gene polymorphism (+1398 A/G) in pathogenesis of these diseases.

METHODS

Serum total immunoglobulin (Ig) E and IL-13 levels were measured by ELISA and the IL-13R A(1) gene (+1398 A/G) was screened by PCR-restriction fragment length polymorphism (RFLP) in 240 asthmatic children (120 atopic and 120 nonatopic) and 120 allergic rhinitis patients compared with 120 age-matched controls.

RESULTS

No significant association was observed between genotype frequencies of the IL-13R A(1) +1398 A/G polymorphism in patients groups compared to in controls. There was a significant increase in serum levels of total IgE & IL-13 towards heterozygous AG and homozygous GG than homozygous AA in atopic asthma, non-atopic asthma and allergic rhinitis groups (P < 0.001 for each). A highly significant increase of serum IL-13 in atopic asthma as compared with controls (P < 0.001) and with nonatopic asthmatics (P < 0.001) was shown.

CONCLUSION

The IL-13R A(1) +1398 A/G polymorphism does not contribute to asthma or allergic rhinitis susceptibility, yet serum IL-13 can be used as a marker in atopic diseases and to differentiate between atopic and non-atopic asthma.

Up-regulation of Orai1 in murine allergic rhinitis

Orai1 is an essential pore-forming subunit of the Ca(2+) release-activated Ca(2+) channels and plays a key role in the store-operated Ca(2+) entry. However, little is known about the function of this pathway in allergic airway diseases. In this study, we evaluated Orai1 expression in normal and allergic rhinitis (AR) mice airway and spleen. AR models were established by repetitive intraperitoneal sensitization followed by intranasal challenge with ovalbumin. Sneezing was counted, and eosinophils infiltration was analyzed through Luna stain. We performed the analysis of Orai1 protein in airway and spleen by immunohistochemical staining, Western blotting and enzyme-linked immunosorbent assay, and quantitatively examined Orai1 mRNA in the above tissues by real-time reverse transcription-polymerase chain reaction. Sneezes and eosinophil counts in the AR group were increased in comparison to those in the normal group. Orai1 protein was expressed in mucosal epithelium and submucosal glands epithelium of airway, and in immune cells of spleen. The immunostaining appeared stronger in AR mice than that in normal ones. Both the Orai1 protein and mRNA levels showed up-regulation in the AR group compared with those in the normal one. Our results indicate that Orai1 is up-regulated in the airway and spleen in allergic inflammation and may participate in the pathogenesis of allergic rhinitis.

Allergic asthma in patients with common variable immunodeficiency

BACKGROUND

Many patients with common variable immunodeficiency (CVID) have a clinical history suggestive of allergic respiratory disease. However, in such individuals, the prevalence of asthma and the role of atopy have not been well established. The objective of this study was to evaluate pulmonary function and identify asthma in patients with CVID. We also investigated the role of IgE as a trigger of asthma in these patients.

METHODS

Sixty-two patients diagnosed with CVID underwent spirometry, as well as skin prick testing and in vitro determination of serum-specific IgE levels for aeroallergens, together with bronchial provocation with histamine and allergen.

RESULTS

The most common alteration identified through spirometry was obstructive lung disease, which was observed in 29 (47.5%) of the 62 patients evaluated. Eighteen (29.0%) of the 62 patients had a clinical history suggestive of allergic asthma. By the end of the study, asthma had been diagnosed in nine (14.5%) patients and atopy had been identified in six (9.7%). In addition, allergic asthma had been diagnosed in four patients (6.5% of the sample as a whole; 22.2% of the 18 patients with a clinical history suggestive of the diagnosis).

CONCLUSION

In this study, CVID patients testing negative for specific IgE antibodies and suspected of having allergic asthma presented a positive response to bronchial provocation tests with allergens. To our knowledge, this is the first such study. When CVID patients with a history suggestive of allergic asthma test negative on traditional tests, additional tests designed to identify allergic asthma might be conducted.

Eosinophilic oesophagitis: clinical manifestations and treatment options. The role of the allergologist

Eosinophilic oesophagitis (EO) is an infrequent disorder that is currently underdiagnosed. It has been described in both adults and in children, and is more prevalent among males. The etiology of EO is not clear, though atopy has been suggested as playing an important role in the development of the disease. The clinical presentation of EO is varied, and a differential diagnosis with other digestive tract disorders is required particularly gastro-oesophageal re-flux. Dysphagia and food bolus impactation within the oesophagus are the most characteristic symptoms. Diagnostic confirmation is obtained from multiple oesophageal biopsy, with the detection in some sample or samples of over 15 eosinophils per high-magnification microscopic field. An allergological study is needed to evaluate the existence of allergens (perennial or seasonal environmental allergens and food allergens) responsible for the eosinophilic infiltration found at oesophageal level. There is no specific treatment for EO, and topical corticosteroids (swallowed) are currently the pharmacological treatment of choice. Dietary therapy in children with food allergy as the causal factor may prove effective, though the existence of polysensitisation complicates the correct implementation of such treatment. Oesophageal dilatation is reserved for cases with severe dysphagia, and is not without complications. Treatment with anti-IL-5, antileukotrienes, azathioprine, 6-mercaptopurine, anti-IgE, etc., could constitute alternatives to topical corticosteroids, although information is still lacking on their long-term safety and efficacy in the paediatric population.

CRTH2 plays an essential role in the pathophysiology of Cry j 1-induced pollinosis in mice

PGD(2) is the major prostanoid produced during the acute phase of allergic reactions. Two PGD(2) receptors have been isolated, DP and CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells), but whether they participate in the pathophysiology of allergic diseases remains unclear. We investigated the role of CRTH2 in the initiation of allergic rhinitis in mice. First, we developed a novel murine model of pollinosis, a type of seasonal allergic rhinitis. Additionally, pathophysiological differences in the pollinosis were compared between wild-type and CRTH2 gene-deficient mice. An effect of treatment with ramatroban, a CRTH2/T-prostanoid receptor dual antagonist, was also determined. Repeated intranasal sensitization with Cry j 1, the major allergen of Cryptomeria japonica pollen, in the absence of adjuvants significantly exacerbated nasal hyperresponsive symptoms, Cry j 1-specific IgE and IgG1 production, nasal eosinophilia, and Cry j 1-induced in vitro production of IL-4 and IL-5 by submandibular lymph node cells. Additionally, CRTH2 mRNA in nasal mucosa was significantly elevated in Cry j 1-sensitized mice. Following repeated intranasal sensitization with Cry j 1, CRTH2 gene-deficient mice had significantly weaker Cry j 1-specific IgE/IgG1 production, nasal eosinophilia, and IL-4 production by submandibular lymph node cells than did wild-type mice. Similar results were found in mice treated with ramatroban. These results suggest that the PGD(2)-CRTH2 interaction is elevated following sensitization and plays a proinflammatory role in the pathophysiology of allergic rhinitis, especially pollinosis in mice.

Intranasal Aspergillus fumigatus exposure induces eosinophilic inflammation and olfactory sensory neuron cell death in mice

OBJECTIVE

To determine the effects of eosinophilic inflammation on olfactory sensory neuron cell death.

STUDY DESIGN

Mice were sensitized to intranasal Aspergillus fumigatus extract and subsequently challenged acutely or chronically with the same allergen. The olfactory neuroepithelium was assessed for immunohistochemical evidence of apoptosis and inflammation.

RESULTS

Sensitized mice challenged with allergen demonstrated elevated eosinophil infiltration of the respiratory and olfactory mucosae, with olfactory sensory neuron apoptosis. Remarkably, massive neuronal apoptosis without eosinophil infiltration occurred in nonsensitized mice after a single dose of extract.

CONCLUSION

Intranasal sensitization with A fumigatus results in a model with multifactorial effects. Protocols using A fumigatus to induce allergic rhinitis may need modification to allow confident interpretation.

SIGNIFICANCE

Fungal allergens may contribute to anosmia through the induction of olfactory sensory neuron apoptosis, with and without prior sensitization.

The role of mast cells in atopy: what can we learn from canine models? A thorough review of the biology of mast cells in canine and human systems

Mast cell research has largely focused on the role of these cells in the early phase of allergic reactions. However, their involvement may well extend beyond this stage, and even reach across nonallergic conditions. Mast cells from different sources have helped advance our knowledge of their biology. Although in vitro and in vivo research in this area has mainly focused on humans, such studies are limited by the extent to which cells from certain human tissues and/or human patients can be collected or studied. While rodents also provide valuable models with which to further our understanding of the behaviour of mast cells and their contribution to allergy, reported differences between human and murine mast cells, and, in some instances, the limitations of in vivo rodent models of mast cell-mediated allergic conditions, preclude their use. In this review, we introduce a relatively unknown mast cell population, that of the dog. Canine mast cells display many phenotypic and functional similarities with their human counterparts, and dogs develop spontaneous and induced allergic diseases that share clinical and pathophysiological features with the human condition. Therefore, the use of canine cells can shed light on the general role of mast cells, particularly in relation to allergic diseases given the potential of in vivo dog models within this field. Here we provide a detailed review of the data reported from in vitro and in vivo studies of canine mast cells, and compare them with results obtained in human systems. We also highlight direct evidence of the mast cell contribution to canine atopy. We conclude that the dog offers useful in vitro and in vivo models in which to investigate mast cell behaviour, and that its use should be considered when undertaking studies aimed either at elucidating the role of mast cells in health and disease, or at prescreening novel therapies prior to entry into man.

Effects of a low-molecular-weight CCR-3 antagonist on chronic experimental asthma

Eosinophils represent one of the main effector cell populations of allergic airway inflammation and allergic bronchial asthma. Their infiltration correlates with many characteristics of the disease, including airway hyperresponsiveness (AHR) and increased mucus production. CCR-3 is the principle chemokine receptor involved in eosinophil attraction into inflamed tissue. Therefore, antagonizing CCR-3 could be a novel promising approach toward asthma therapy. We investigated the effect of a low-molecular-weight CCR-3 antagonist on established airway inflammation in a chronic model of experimental bronchial asthma. For this purpose, BALB/c mice intraperitoneally sensitized with ovalbumin (OVA) were chronically challenged with OVA aerosol to induce chronic airway inflammation and airway remodeling. The effect of antagonizing CCR-3 on asthma pathology was examined in BAL and lung histology. Airway reactivity was assessed by head-out body plethysmography. Treatment with the CCR-3 antagonist resulted in a marked reduction of eosinophils in the bronchoalveolar lumen and in airway wall tissue, whereas infiltration of lymphocytes or macrophages remained unchanged. The reduction in eosinophil infiltration was accompanied by normalization of AHR and prevention of goblet cell hyperplasia, indicating reduced mucus production. Furthermore, antagonizing CCR-3 prevented airway remodeling as defined by subepithelial fibrosis and increased accumulation of myofibrocytes in the airway wall of chronically challenged mice. These data demonstrate that antagonism of CCR3 reduces eosinophil numbers, which is accompanied by diminution of asthma pathology in a mouse model of established chronic experimental asthma. Therefore, antagonizing CCR-3 represents a new approach toward a promising asthma therapy.

Development of a murine model of chronic rhinosinusitis

OBJECTIVE

The aim of this study was to develop a mouse model of chronic eosinophilic rhinosinusitis.

STUDY DESIGN

Mice were sensitized to Aspergillis fumigatus (Af) extract by intraperitoneal injection. The animals subsequently received nasal challenges with Af extract 3 times per week for 12 weeks. Sinonasal complexes were studied histologically by the study otolaryngologists and pathologists to characterize the inflammatory response.

SETTING

Animal care facility at an academic institution.

RESULTS

A chronic eosinophilic inflammatory response was evoked in all study animals. Statistical analysis was performed for inflammation, secretory cell hyperplasia, mast cells, and eosinophils. There were very significant differences (P<0.0005) between control and study mice in all categories.

CONCLUSION

Prolonged nasal challenge of Af extract creates an inflammatory response in murine nasal mucosa that mimics human chronic eosinophilic rhinosinusitis.

SIGNIFICANCE

A murine model for chronic rhinosinusitis is reported that may facilitate future investigations into disease pathophysiology.

EBM RATING

B-2.

Physiologic assessment of allergic rhinitis in mice: role of the high-affinity IgE receptor (FcepsilonRI)

BACKGROUND

There have been few reports using animal models to study the development of allergic rhinitis. Characterization of such a model in mice would be advantageous given the availability of reagents and gene-manipulated strains.

OBJECTIVE

We sought to develop a murine model of allergic rhinitis in the absence of lower airway changes.

METHODS

After sensitization and challenge, both wild-type and FcepsilonRI-deficient mice were studied for their ability to develop early- and late-phase nasal responses. In the invasive approach, direct measurements of nasal airway resistance (R(NA)) were obtained; in the noninvasive approach using whole-body plethysmography, respiratory frequency and expiratory and inspiratory times were monitored. In both approaches, nasal responses were determined either acutely after challenge (early phase) or 24 hours after challenge (late phase).

RESULTS

After challenge of sensitized mice, R(NA) significantly increased. In parallel, respiratory frequency significantly decreased and was highly correlated with the increases in R(NA). Sensitized wild-type mice had an early-phase nasal response and persistent nasal blockage (late-phase response) after allergen challenge. In contrast, sensitized and challenged FcepsilonRI alpha-chain-deficient mice did not have an early-phase nasal reaction and exhibited reduced nasal blockage and lower IL-13 levels in nasal tissue homogenates.

CONCLUSIONS

These data indicate that FcepsilonRI is essential to development of an early-phase nasal response and contributes to the development of the late-phase nasal response. These invasive and noninvasive approaches provide new opportunities to evaluate the mechanisms underlying the development of nasal responses to allergen and to assess various therapeutic interventions.

Macrophage migration inhibitory factor (MIF) contributes to the development of allergic rhinitis

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine whose expression has been found to be critical to the generation of antigen-specific immune responses. Recent studies suggested that MIF played a role in the initiation and maintenance of allergic diseases. To elucidate MIF's role in the pathogenesis of allergic rhinitis (AR), we sensitized MIF-deficient gene knockout (KO) mice and wild-type (WT) mice intraperitoneally with ovalbumin (OVA) and compared their clinical symptoms and allergic responses after intranasal challenge. Antigen-induced nasal symptoms were significantly reduced in MIF KO mice compared to WT mice. Histological examination of nasal mucosa showed that the number of infiltrating eosinophils in MIF KO mice was significantly lower than that in WT mice (P < 0.05). The concentration of TNF-alpha in nasal mucosa was also significantly lower in MIF KO mice than in WT mice (P < 0.05). We have demonstrated that the absence of MIF affects several aspects of experimental AR. One mechanism by which these effects might be mediated is by down regulating TNF-alpha. The block of allergic inflammation in MIF KO mice suggests that MIF may play a role in the allergic response.

Atopic march: link to upper airways

PURPOSE OF REVIEW

This review examines the role of the upper airways in the atopic march. Evidence examining the theory that allergic rhinitis precedes asthma will be discussed. In addition, the role of allergic rhinitis as an end point in the atopic march will be reviewed.

RECENT FINDINGS

Ciprandi and colleagues found that nasal symptoms, airflow and markers of inflammation (eosinophils, cytokine levels) directly correlated with lower airway markers. This confirms previous studies finding that many patients with allergic rhinitis have lower airway hyperreactivity or bronchial hyperresponsiveness and the link between upper and lower airways. Leynaert and colleagues questioned over 90 000 individuals and found that patients with rhinitis have increased risk for asthma and lower airway reactivity compared with patients without rhinitis. In the German Multicenter Atopy Study, a longitudinal study of 1300 children, patients with atopic dermatitis were found to have increased risk for asthma at 7 years of age. Patients with atopic dermatitis and no wheezing in the first 3 years, however, did not have an increased risk for developing current wheezing or bronchial hyperresponsiveness at 7 years of age. It was proposed that atopic dermatitis and asthma are linked, but atopic dermatitis does not precede asthma.

SUMMARY

Allergic rhinitis is a risk factor for asthma and can precede asthma in the atopic march.

Occupational asthma

Substantial epidemiologic and clinical evidence indicates that agents inhaled at work can induce asthma. In industrialized countries, occupational factors have been implicated in 9 to 15% of all cases of adult asthma. Work-related asthma includes (1) immunologic occupational asthma (OA), characterized by a latency period before the onset of symptoms; (2) nonimmunologic OA, which occurs after single or multiple exposures to high concentrations of irritant materials; (3) work-aggravated asthma, which is preexisting or concurrent asthma exacerbated by workplace exposures; and (4) variant syndromes. Assessment of the work environment has improved, making it possible to measure concentrations of several high- and low-molecular-weight agents in the workplace. The identification of host factors, polymorphisms, and candidate genes associated with OA is in progress and may improve our understanding of mechanisms involved in OA. A reliable diagnosis of OA should be confirmed by objective testing early after its onset. Removal of the worker from exposure to the causal agent and treatment with inhaled glucocorticoids lead to a better outcome. Finally, strategies for preventing OA should be implemented and their cost-effectiveness examined.

Haemopoietic mechanisms in murine allergic upper and lower airway inflammation

Eosinophil recruitment to the airways, including involvement of haemopoietic eosinophil-basophil progenitors (Eo/B-CFU), is primarily regulated by interleukin-5 (IL-5) and eotaxin. In this study, we investigated the haemopoietic mechanisms in upper and lower airway eosinophilic inflammation. Ovalbumin (OVA) sensitized and challenged BALB/c mice were used to establish isolated upper (UAC), isolated lower (LAC), or combined upper and lower airway (ULAC) inflammation. Airway, blood and bone marrow responses were evaluated in each model. Numbers of airway eosinophils and CD4(+) cells were increased significantly in the nasal mucosa in UAC and ULAC mice, and in the lung tissue in LAC and ULAC groups. Levels of IL-5 and eotaxin were increased significantly in the nasal lavage fluid (NL) in UAC and ULAC mice, and in the bronchoalveolar lavage fluid (BAL) in LAC and ULAC groups. The proportion of IL-5-responsive bone marrow Eo/B-CFU was significantly higher than the control in all treatment groups, but peaked much earlier in the ULAC group. Kinetic studies revealed that IL-5 and eotaxin in NL, BAL and serum peaked between 2 and 12 hr after OVA challenge in ULAC mice, and at 24 hr in UAC mice, related to the timing of maximal progenitor responses. These data support the concept that the systemic mechanisms linking rhinitis to asthma depend on the location and extent of airway allergen exposure.

Haplotypes of G protein-coupled receptor 154 are associated with childhood allergy and asthma

RATIONALE

Allergic diseases are influenced by both genes and environment. A 70-kb haplotype block in the G protein-coupled receptor for asthma susceptibility gene (GPR154; alias GPRA) on chromosome 7p was recently identified to influence susceptibility to asthma and elevated total serum IgE levels in adults.

OBJECTIVES

To assess the impact of GPR154 on childhood allergic disease, including allergic sensitization, asthma, and rhinoconjunctivitis, in study populations with diverse environmental backgrounds.

METHODS

We studied farm children, Steiner school children, and two reference groups from five Western European countries in the cross-sectional PARSIFAL (Prevention of Allergy Risk factors for Sensitization In children related to Farming and Anthroposophic Lifestyle) study and a sample of children from the Swedish birth cohort study BAMSE. DNA samples from 3,113 PARSIFAL and 800 BAMSE children were genotyped for 7 GPR154 polymorphisms and haplotypes were inferred. The proportions of alleles and haplotypes (H1-H7) were compared in affected children with their healthy counterparts.

RESULTS

Data indicate a global association of the haplotype block to sensitization (allergen-specific serum IgE > or = 0.35 kU/L, p = 0.022), with significant haplotype-specific associations for H1, H5, and H6. Haplotypes H1 and H5 were also significantly associated with childhood allergic asthma (p = 0.045 and p = 0.023, respectively), and H5 to asthma regardless of sensitization. A broader involvement of GPR154 in allergic diseases was further supported in allergic rhinoconjunctivitis (H3: p = 0.046). The associated haplotypes could be allocated into risk (H5/H6) and nonrisk (H1/H3) groups, a pattern supported by allelic association of single nucleotide polymorphisms (SNPs) rs324384 and rs324396.

CONCLUSIONS

Our results indicate that polymorphisms and haplotypes in the haplotype block of GPR154 are associated with asthma, rhinoconjunctivitis, and sensitization in European children.

Mouse models of global airway allergy: what have we learned and what should we do next?

Recent epidemiological and clinical data indicate that allergic rhinitis and asthma coexist and should be considered as one airway allergy syndrome. In spite of the importance of this new concept of global airway allergy, it has not fundamentally changed our daily diagnostic and therapeutic strategies so far because of the lack of essential clues to understand the correlation between allergic inflammation in upper and lower airways. Because of the resemblance of experimentally induced allergic airway inflammation in mice to inflamed airways of allergic patients, mouse models can enhance our insight into mechanisms underlying the global airway allergy syndrome. We here review data generated in mice that are relevant for understanding the development of airway allergy and provide new options for research on the so-called 'united airway disease'.

Failure of sputum eosinophilia after eotaxin inhalation in asthma

BACKGROUND

Eotaxin is a chemokine specific for eosinophils and may play an important role in eosinophil recruitment in asthma. The effects of eotaxin inhalation on sputum and blood eosinophils, exhaled nitric oxide (NO), and bronchial responsiveness were determined.

METHODS

Eotaxin was administered by nebulisation to asthma patients in three studies: (1) an open dose finding study with eotaxin (5, 10 and 20 microg) to two asthmatic subjects; (2) a randomised placebo controlled study with 20 microg eotaxin to five asthmatic subjects and five normal volunteers; and (3) a randomised placebo controlled study with 40 microg eotaxin to nine asthmatics. Forced expiratory volume in 1 second (FEV(1)), exhaled NO, and blood eosinophils were measured before and hourly for 5 hours after nebulisation and at 24 and 72 hours. Methacholine bronchial challenge and sputum induction were performed before and at 5, 24, and 72 hours after nebulisation.

RESULTS

In the two placebo controlled studies there was no change in sputum eosinophil count and sputum eosinophilic cationic protein concentration after eotaxin inhalation compared with placebo. FEV(1), exhaled NO, and methacholine PC(20) did not change. However, high dose eotaxin (40 microg) induced an increase in sputum neutrophil count compared with placebo (p<0.05).

CONCLUSIONS

Inhaled eotaxin up to 40 microg induced no changes in sputum eosinophil count but at 40 microg it increased the sputum neutrophil count. The significance of this finding is unknown.

Nasal involvement in allergic asthma

Even since the late 19th century, a relationship has been suspected between upper airway disease and the subsequent development or aggravation of asthma symptoms. To date, it has been generally accepted that pathologic conditions of the upper airways, e.g. allergic rhinitis, chronic sinusitis and nasal polyposis, may influence the lower airways. However, the mechanisms underlying this relationship were, for a long time, poorly understood. Recently, evidence has been accumulating which indicates a systemic connection as one of the responsible mechanisms in nasobronchial crosstalk. In this review, the pathophysiologic and immunologic aspects of the interaction between upper and lower airways will be discussed.

Roles of FcgammaRIIB in nasal eosinophilia and IgE production in murine allergic rhinitis

The low-affinity IgG Fc receptor, FcgammaRIIB, displays inhibitory potential in experimental models such as autoimmune diseases. However, whether this receptor is involved in the onset of allergic diseases remains unknown. This study examines the role of FcgammaRIIB in the initiation of allergic rhinitis in mice. Repeated intranasal sensitization with Schistosoma mansoni egg antigen (SEA) induced SEA-specific IgE and marked nasal eosinophilia in high-responder BALB/c mice. FcgammaRIIB gene-deficient (-/-) BALB/c mice displayed severe eosinophilia compared with that of wild-type counterparts. However, FcgammaRIIB -/- mice conversely produced less SEA-specific IgE. The production of interleukin (IL)-4 but not of IL-5 or IFN-gamma by nasal mononuclear cells was also decreased in FcgammaRIIB -/- mice, suggesting that the exacerbation of nasal eosinophila in FcgammaRIIB -/- mice is independent of the local IL-5 levels. The findings in low responder C57BL/6 mice were similar. In addition, nasal eosinophilia in FcgammaRIIB -/- mice passively sensitized with SEA was exacerbated, and conversely, specific IgE production was inhibited after a nasal challenge. These results suggest that FcgammaRIIB plays a regulatory role in the initiation of allergic rhinitis that is independent of either mouse strain or type of sensitization.

Expression of substance P and vanilloid receptor (VR1) in trigeminal sensory neurons projecting to the mouse nasal mucosa

Substance P and neurokinin A (NKA) have potent pro-inflammatory effects in the airways. The release of these neuropeptides from primary afferent (sensory) nerve endings to various stimuli is considered to be induced by activation of the capsaicin (vanilloid) receptor (VR1). In this study, retrograde neuronal tracing studies were combined with immunohistochemistry for VR1 and substance P to investigate the occurrence and distribution of substance P and VR1 receptor expression in mouse trigeminal neurons that were identified by retrograde labeling with Fast blue dye from the nasal mucosa. Fast blue signaling was observed in mucosa layers of the right nasal cavity and in sensory trigeminal neurons close to the division of the ophthalmic and maxillary nerve. Expression patterns of VR1 and substance P were found with different frequencies: 11.3+/-1.2% (mean+/-SEM) were immunoreactive for VR1, 4.9+/-1.1% for VR1 and SP, and 6.4+/-1.3% only for VR1 but not for SP. These VR1-positive neurons were partly binding to lectin I-B4, indicating VR1-expression in non-peptidergic upper airway C-fibers. In conclusion, based on the extent of SP and VR1 co-localization in nasal afferent neurons, the present study suggests that, following a peripheral activation of the VR1 receptor on SP afferents, there could be a triggering of SP-mediated phenomena, including those related to inflammation, such as plasma extravasation.

Immune responses in the lung and local lymph node of A/J mice to intranasal sensitization and challenge with adjuvant-free ovalbumin

Pathologic features of IgE-mediated allergic airway diseases include airway infiltration of inflammatory cells (eg, lymphocytes, plasma cells, and eosinophils) and mucous cell metaplasia (MCM) in airway epithelium. CD4(+) T lymphocytes, specifically those producing a type 2 (Th2) cytokine profile, are necessary for the induction of IgE-mediated allergic airway responses. Most experimental models of IgE-mediated allergic airway disease use systemic (eg, intraperitoneal) administration of an allergen coupled with an adjuvant to sensitize animals. Cytokine changes are measured in a number of ways including in bronchoalveolar lavage fluid (BALF) or lymph node cells stimulated ex vivo. The primary objective of this study was to test the hypothesis that intranasal sensitization and challenge of mice with ovalbumin in the absence of an adjuvant will induce the pathologic features that are characteristic of IgE-mediated allergic airway disease. Another objective was to determine if intranasal delivery of this allergen will result in the induction of a profile of cytokine gene expression in the lung and tracheobronchial (TB) lymph node, that is typical of immunologic changes associated with IgE-mediated allergic airway disease. Only mice that were intranasally sensitized and challenged with ovalbumin exhibited pulmonary lesions that included marked MCM in the respiratory epithelium lining the nasal and pulmonary airways, and an associated mixed inflammatory cell influx consisting of lymphocytes, plasma cells and eosinophils. Ovalbumin-treated mice also exhibited enhanced expression of the Th2 cytokine mRNAs IL-4, IL-5, IL-10, and IL-13 in the lung and IL-4 in the TB lymph node, and concurrent increases in ovalbumin-specific IgE in the serum. The results of this study indicate that A/J mice intranasally instilled with ovalbumin without adjuvant have the hallmark histopathologic and immunologic features of IgE-mediated allergic airway disease of humans.

The role of chemical mediators in eosinophil infiltration in allergic rhinitis in mice

The involvement of chemical mediators other than histamine in eosinophil infiltration in the nasal mucosa was studied using histamine H(1) receptor-deficient mice. Histamine H(1) receptor-deficient mice and wild-type controls were immunized with ovalbumin and consecutive topical antigen instillation was performed. Histological alterations and eosinophil infiltration into the nasal mucosa of mice were examined. Diffuse infiltration of inflammatory cells and edema after sensitization with antigen were observed in the nasal mucosa in both wild-type and histamine H(1) receptor-deficient mice. The number of eosinophils in the nasal mucosa in mice sensitized with antigen was significantly increased as compared with controls. The number of eosinophils in the nasal mucosa was significantly decreased by cetirizine and epinastine, ramatroban and zafirlukast in wild-type mice. Not only histamine but also thromboxane A(2) and leukotrienes play important roles in allergic rhinitis, especially in the late phase participating in nasal eosinophilia.

Site-specific sensitization in a murine model of allergic rhinitis: role of the upper airway in lower airways disease

BACKGROUND

Allergic rhinitis (AR) is the most common atopic disease with strong links to asthma. We have developed a murine model of AR to study nasal, bronchial, and systemic immune response to local allergen stimulation.

OBJECTIVES

The purpose of this study was to develop and characterize a murine model of AR.

METHODS

Six- to 8-week-old BALB/c mice were sensitized by means of intranasal (local) application of ovalbumin (OVA) or systemic intraperitoneal injection. They were then challenged with intranasal OVA, and allergic response was assessed.

RESULTS

Intranasal particle deposition was found to be exclusively in the nares. All sensitized animals showed increased levels of OVA-specific serum IgE and IgG after challenge, although the timing to maximal response varied with the route and dose of allergen used. Histology of the upper and lower airways showed marked eosinophilic infiltration, and analysis of bronchoalveolar lavage fluid showed increased IL-5 and PMN infiltrates after challenge.

CONCLUSION

Using exclusive local sensitization and challenge of mouse nares, we were able to demonstrate inflammatory changes in both the upper and lower airways, even though distribution of allergen particles appeared to be only in the nares of these animals. This provides further evidence for the importance of the upper airway in lower airways disease. We have shown that the route of administration greatly affects the characteristics of the subsequent immune responses.

Interleukin-13 gene polymorphism G4257A is associated with atopic dermatitis in Japanese patients

Interleukin (IL)-13 plays an important role in the induction of immunoglobulin E (IgE) and in the pathogenesis of atopic dermatitis (AD). We investigated the allele and genotype frequencies of three IL-13 single nucleotide polymorphisms (SNPs) (A704C and C1103T in the promoter region and G4257A in exon 4) in Japanese patients with AD. For A704C and C1103T SNPs, there were no significant differences in allele or genotype frequencies between AD patients and controls. For G4257A SNP, A allele was significantly increased in AD patients (39.5%) compared with controls (29.4%) (P = 0.016). The same proportion of each genotype and allele was observed in the patient subgroup with and without asthma. Serum IgE levels and peripheral eosinophil counts were not significantly different among genotypes in G4257A SNP. There was also no significant difference in allele or genotype frequencies between AD patients with mild disease and those with severe disease, between those with family history of AD and those without it, or between those with family history of atopic disorders and those without it. This result suggests that 4257A allele is associated with susceptibility to AD and that it may function in the pathogenesis of AD itself, presumably by other mechanisms than inducing IgE production.

Modulation of murine allergic rhinosinusitis by CpG oligodeoxynucleotides

BACKGROUND

Allergic rhinosinusitis is characterized by eosinophilic inflammation of the upper airway, which is induced by TH-2 cytokines. CpG oligodeoxynucleotides (ODN) are known to induce TH-1 and to suppress TH-2 cytokines in a variety of settings, including murine models of asthma.

OBJECTIVE

To examine the effect of CpG ODN in a murine model of upper airway allergic inflammation and to correlate with reduction of its manifestations of sneezing and nasal scratching.

METHODS

BALB/c mice were sensitized using Ovalbumin (Ova) intraperitoneally and challenged with aerosolized Ova. CpG ODN were administered at the time of Ova sensitization. Outcomes measured included nasal symptoms, submucosal eosinophilia in the areas lined by respiratory or olfactory epithelium, and bone marrow eosinophilia. To delineate the mechanism of CpG ODN-induced suppression of eosinophilic inflammation, in vitro experiments were carried out to examine the effect of stimulation with Ova on splenocytes obtained from mice that were treated with CpG or control ODN (or no ODN) in vivo. Supernatant was collected after 72 hours of incubation and cytokines were measured by enzyme linked immunosorbent assay.

RESULTS

CpG ODN administered at the time of Ova sensitization effectively abrogated nasal symptoms and eosinophilic upper airway inflammation compared with mice treated with control ODN or with no ODN. Cytokine data revealed that Ova sensitization suppressed IFN-gamma and induced IL-4 and IL-5 compared with non-sensitized mice. CpG ODN treatment reversed these effects.

CONCLUSION

CpG ODN prevents the development of TH-2-mediated eosinophilic inflammation and symptoms in a murine model of allergic rhinosinusitis.

Eotaxin but not MCP-3 induces eosinophil influx into nasal fluid in allergic patients

BACKGROUND

Eotaxin and MCP-3 (CC chemokines), owing to their preferential action on eosinophils, seem to be the very importance in the patophysiology of allergic rhinitis and asthma. The purpose of this study was to examine the effect of intranasally administered eotaxin and MCP-3 after specific allergen priming on the influx of inflammatory cells and their soluble mediators into the nasal mucosa.

METHODS

Eotaxin and MCP-3 have been applied intranasally at the increasing doses of 1, 5 and 10 microg to allergic patients after allergen priming. The 'nasal pool' technique was used. The cell count and biochemical parameters in nasal lavage were evaluated before 30 min, and 4 and 24 h after the challenge with chemokines.

RESULTS

Both eotaxin and MCP-3 induced the increase in clinical 'score' lasting till 24 h. Eosinophil influx into nasal mucosa after provocation with eotaxin was also observed. The challenge with MCP-3 did not induce any significant changes in nasal lavage fluid.

CONCLUSIONS

Eotaxin is likely to play an important role in the pathogenesis of allergic conditions in humans. MCP-3 did not induce inflammatory cell influx into nasal mucosa. The role of this chemokine in the pathogenesis of allergic inflammation is difficult to assess and requires further studies.

Carbohydrates expressed on Aspergillus fumigatus induce in vivo allergic Th2-type response

BACKGROUND

The mould Aspergillus fumigatus (Af) causes several forms of Th2-biased diseases such as Type I respiratory allergies. This mould contains abundant carbohydrates including glucan, chitin and galactomannan. However, little is known on whether these carbohydrates directly drive Th2 responses in vivo.

OBJECTIVE

We sought to determine the relative role of carbohydrates expressed on crude extracts of Af in the induction of Th2-type antibody production and local eosinophila in mice.

METHODS

Carbohydrates on native Af were destroyed by sodium metaperiodate under mild conditions. CBA/J mice were sensitized intranasally with native, periodate-treated or mock-treated Af. Histologic changes and production of Af-specific IgE, IgG1 and IgG2a, as well as serum total IgE were determined. Inhibition ELISA for Af-specific IgE was performed using periodate-treated Af as an inhibitor.

RESULTS

Mice sensitized with periodate-treated Af displayed significant decreases in both total and specific IgE levels in comparison to mice sensitized with native or mock-treated Af. Furthermore, sensitization and subsequent challenge with periodate-treated Af significantly reduced the degree of eosinophil recruitment into the nasal mucosa, compared to the controls. On the other hand, competitive inhibition showed that periodate-treated Af could inhibit binding between native Af and specific IgE in a similar manner to that of native and mock-treated Af.

CONCLUSION

These results suggest that carbohydrates on Af play a key role as internal adjuvants in inducing the allergic Th2-type response and are not the targets of the induced IgE response.

CCR3 is essential for skin eosinophilia and airway hyperresponsiveness in a murine model of allergic skin inflammation

The CC chemokine receptor 3 (CCR3) is expressed by eosinophils, mast cells, and Th2 cells. We used CCR3(-/-) mice to assess the role of CCR3 in a murine model of allergic skin inflammation induced by repeated epicutaneous sensitization with ovalbumin (OVA), and characterized by eosinophil skin infiltration, local expression of Th2 cytokines, and airway hyperresponsiveness (AHR) to inhaled antigen. Eosinophils and the eosinophil product major basic protein were absent from the skin of sham and OVA-sensitized CCR3(-/-) mice. Mast cell numbers and expression of IL-4 mRNA were normal in skin of CCR3(-/-) mice, suggesting that CCR3 is not important for infiltration of the skin by mast cells and Th2 cells. CCR3(-/-) mice produced normal levels of OVA-specific IgE, and their splenocytes secreted normal amounts of IL-4 and IL-5 following in vitro stimulation with OVA, indicating effective generation of systemic Th2 helper responses. Recruitment of eosinophils to lung parenchyma and bronchoalveolar lavage (BAL) fluid was severely impaired in CCR3(-/-) mice, which failed to develop AHR to methacholine following antigen inhalation. These results suggest that CCR3 plays an essential role in eosinophil recruitment to the skin and the lung and in the development of AHR.

Food allergy. Mechanisms, diagnosis, and management in children

We eat approximately two to three tons of food in our lifetime, but most people do not have an adverse reaction to foods. Many people believe that they have an allergic reaction to foods; however, the actual incidence confirmed by history and challenges suggests a prevalence rate closer to 2% to 8% in young infants and less than 2% in adults.

Induction, distribution and modulation of upper airway allergic inflammation in mice

BACKGROUND

To further elucidate mechanisms of human allergic rhinosinusitis, we studied the induction, distribution and modulation of allergen-induced upper airway inflammation in a BALB/c mouse model.

METHODS

Allergic inflammation induced with ovalbumin (OVA) by intraperitoneal (IP) injection in alum was compared to repeated intranasal instillation. The type and distribution of inflammatory cells was compared in the respiratory and olfactory epithelial compartments. Eosinophil distribution was assessed using Scarlet Red stain and a polyclonal antibody recognizing eosinophil major basic protein (MBP). The role of interleukin (IL)-5 in upper airway inflammation was tested by administration of polyclonal anti-IL-5 antibody during the sensitization protocol.

RESULTS

Unsensitized control mice receiving saline failed to develop upper airway eosinophil infiltration. IP OVA-sensitized mice developed marked upper airway mucosal eosinophil infiltration after aerosol OVA challenge, whereas repeated intranasal instillation of OVA produced qualitatively similar, but less intense eosinophil infiltration. Using either sensitization protocol, eosinophil infiltration was seen in areas of the lower portion of the nasal septum, the floor and the lower lateral walls of the mid-caudal region of the nasal cavity. Immunofluorescence staining for MBP confirmed this distribution of eosinophils but also demonstrated some eosinophils in the maxillary sinuses and in circumscribed regions of the ethmoturbinates. All areas of eosinophil infiltration were lined by respiratory epithelium. The selective infiltration of respiratory but not olfactory epithelium by eosinophils was unassociated with a measurable induction of epithelial ICAM-1 or eotaxin expression. OVA-induced upper airway eosinophil infiltration was found to be IL-5 dependent, since administration of a polyclonal anti-IL-5 antibody (TRFK-5) during OVA sensitization resulted in a marked modulation (80% decrease) in eosinophil infiltration in response to subsequent OVA challenge.

CONCLUSION

The mouse upper airway, specifically in areas containing respiratory epithelium, is a target for OVA-induced allergic inflammation. This selective infiltration of respiratory, but not olfactory, epithelium is, in part, dependent upon IL-5. This model is useful for further dissection of the inflammatory response with genetic manipulations and targeted immunological approaches.

Sex-related differences in the initiation of allergic rhinitis in mice

BACKGROUND

Several clinical and epidemiologic studies have investigated sex differences in the prevalence of allergic rhinitis. At present, however, no reports have demonstrated such differences in experimental models with local, but not parenteral, sensitization with antigens that may reflect natural exposure to allergens. We have recently developed murine models of allergic rhinitis after repeated intranasal sensitization with antigens in the absence of adjuvants. In this study, we investigated the role of sex in the initiation of the disease in vivo.

METHODS

Male and female CBA/J and BALB/c mice were sensitized intranasally with phospholipase A2 (PLA2) and Schistosoma mansoni egg antigen (SEA), respectively, in the absence of adjuvants. After the repeated sensitization, serum Ab titers against the sensitizing antigen and nasal eosinophilia were determined. In addition, the involvement of androgen in IgE synthesis was investigated in castrated CBA/J male mice with or without testosterone administration.

RESULTS

Females produced significantly higher levels of PLA2-specific IgE than males in CBA/J mice sensitized with PLA2. On the other hand, both titers of PLA2-specific IgG1 and nasal eosinophilia did not significantly differ between the two groups. Castrated male mice produced significantly higher amounts of PLA2-specific IgE than sham-treated male mice. In addition, PLA2-specific IgE production decreased in castrated mice treated with testosterone. Sexual differences in the production of Ag-specific IgE were not seen in BALB/c mice after the sensitization with SEA.

CONCLUSION

These results suggest that sex is responsible for the production of Ag-specific IgE, but not IgG1 or nasal eosinophilia, and that androgen appears to be involved in the in vivo production of specific IgE in male mice.

Eosinophilic rhinitis accompanies the development of lower airway inflammation and hyper-reactivity in sensitized mice exposed to aerosolized allergen

BACKGROUND

Allergic rhinitis is a risk factor for the development of asthma. About 80% of asthmatic patients also have rhinitis. However, the pattern of induction of allergic rhinitis and asthma remains unclear.

OBJECTIVE

The purpose of this study was to investigate the development of upper airway inflammation in mice during the development of an asthma-like disease and after an acute allergen provocation.

METHODS

BALB-c mice were sensitized intraperitoneally (i.p) to ovalbumin (OA, days 1-13) and were challenged with aerosols of either OA or saline on 8 consecutive days (days 33-40). In a second experiment, chronic exposure for 8 days was followed by 10 days of rest and then an acute nebulized allergen provocation was performed (day 50). Inflammatory parameters were investigated at different time-points.

RESULTS

Upper and lower eosinophilic airway inflammation were simultaneously induced in the course of repeated inhalations of nebulized OA, as shown by analyses of nasal and broncho-alveolar lavage fluids and histological sections of the nose and bronchi. Mice that developed bronchial hyper-responsiveness also had increased thickness of the nasal mucosa on magnetic resonance image (MRI) scans. When chronic exposure was followed by acute allergen provocation, the latter caused a systemic increase in IL-5 levels, with a concomitant rise in blood and airway eosinophils, primarily in the nose.

CONCLUSIONS

Simultaneous induction of eosinophilic inflammation in the nose and lungs was found in a mouse model of respiratory allergy. These findings support the viewpoint that upper and lower airway disease represent a continuum of inflammation involving one common airway and provide evidence for the concept of global airway inflammation after inhalation of allergen.