Unique mechanistic features of allergic rhinitis

Mometasone furoate improves congestion in patients with moderate-to-severe seasonal allergic rhinitis

BACKGROUND

A recent survey estimated that 85% of patients with allergic rhinitis experience nasal congestion. This symptom considerably impacts quality of life.

OBJECTIVE

To evaluate the effectiveness of mometasone furoate nasal spray (MFNS) in subjects with seasonal allergic rhinitis (SAR) experiencing moderate-to-severe nasal congestion.

METHODS

Data were obtained from 4 randomized, double-blind, placebo-controlled studies of MFNS 200 microg once daily in patients with SAR. Subject-evaluated nasal congestion score data (score range 0-3) from subjects receiving MFNS or placebo were analyzed as a pool and grouped according to baseline score (all pts. with scores >2.5, >2.75, or 3.0). The 2-week average change in score from baseline was analyzed.

RESULTS

Significant improvements in mean nasal congestion score were seen with MFNS (n = 490) versus placebo (n = 492; p < 0.001). Overall, there was a 27% improvement in this score in patients receiving MFNS versus 13% with placebo. MFNS produced significant reductions in the nasal congestion score compared with placebo, even in patients with the most severe baseline congestion (0.98 vs 0.52; p < 0.001). Improvements in scores from baseline of 32%, 33%, and 34% were seen with MFNS versus 22%, 21%, and 18% with placebo (for baseline scores of >2.5, >2.75, or 3.0, respectively), confirming the effectiveness of MFNS regardless of congestion severity. This represents an improvement approximating a decrease from severe to moderate congestion or from moderate-to-severe to mild-to-moderate congestion. MFNS was well tolerated.

CONCLUSIONS

MFNS 200 microg once daily produces statistically significant improvements in nasal congestion score compared with placebo, alleviating severe congestion in patients with moderate-to-severe SAR.

Nasal allergies and beyond: a clinical review of the pharmacology, efficacy, and safety of mometasone furoate

Mometasone furoate nasal spray (MFNS; Nasonex, Schering-Plough Corporation, Kenilworth, NJ, USA) is an effective and well-tolerated intranasal corticosteroid approved for the prophylactic treatment of seasonal allergic rhinitis, and the treatment of perennial allergic rhinitis. MFNS is a potent molecule with a rapid onset of action and excellent safety and efficacy profiles. Having recently received approval for the treatment of nasal polyposis, data indicate that MFNS may also be effective in rhinosinusitis.

Induction of nasal hyper-responsiveness by allergen challenge in allergic rhinitis: the role of afferent and efferent nerves

BACKGROUND

Hyper-responsiveness of nasal secretory function and volume changes are features of allergic rhinitis (AR) that are mediated in part by neural mechanisms. The finding of nasal hyper-responsiveness in subjects with AR who are currently symptomatic, but not in those who are currently out of season and asymptomatic, suggests that induction of neural reflexes in allergic subjects occurs as a result of allergic inflammation.

OBJECTIVES

To investigate whether allergen exposure in subjects with asymptomatic seasonal allergic rhinitis (SAR) may lead to induction of neural reflexes, and to investigate the components of the reflexes involved in this induction.

METHODS

Asymptomatic subjects with (out-of-season) SAR underwent a nasal bradykinin challenge, before and 24 h after preceding ipsilateral (n = 11) and contralateral (n = 11) antigen challenge. Challenges were performed and nasal secretions collected using filter paper disks, and changes in nasal minimal cross-sectional area (A(min)) were measured using acoustic rhinometry.

RESULTS

Preceding ipsilateral antigen challenge led to the induction of a contralateral secretory reflex (P = 0.01), which was absent in control experiments (P = 0.34). Ipsilateral secretion weights were also enhanced. Preceding contralateral antigen challenge also induced a contralateral secretory reflex (P = 0.03). Enhancement of the reduction in contralateral A(min) was also seen (P = 0.02). Ipsilateral responses were unchanged.

CONCLUSIONS

Allergen exposure in asymptomatic allergic subjects leads to induction of neural reflexes, resulting in nasal hyper-responsiveness, which persists beyond the resolution of the acute allergic response. Our data suggest that the mechanisms of allergen-induced hyper-responsiveness involve both afferent and efferent components.

Identification of beta-tubulin isoform V as an autoantigen in allergic rhinitis by a proteomic approach

Autoantibodies to IgE and beta2-adrenergic receptor have been reported in patients with allergic rhinitis. To investigate whether autoimmunity in allergic rhinitis is directed to such limited molecules or directed to a wide range of self proteins, we here attempted to survey autoantigens/autoantibodies comprehensively, using proteomics. Specifically, we separated proteins extracted from peripheral blood mononuclear cells by 2-dimensional electrophoresis and then detected autoantigens by subsequent western blotting with sera from patients with allergic rhinitis. As a result, we detected multiple autoantigens, some of which were further identified by mass fingerprinting. Next, we confirmed antigenicity of one of the identified autoantigens, beta-tubulin isoform V (beta-tubV), using a recombinant protein and then measured prevalence of the anti-beta-tubV autoantibodies. As a result, 52% of the tested patients with allergic rhinitis were found to possess anti-beta-tubV autoantibodies. Our study indicates that autoimmunity is a common phenomena and beta-tubV is one of the major autoantigens in allergic rhinitis.

Allergic rhinitis in children : diagnosis and management strategies

The incidence of allergic rhinitis has been increasing for the last few decades, in keeping with the rising incidence of atopy worldwide. Allergic rhinitis has a prevalence of up to 40% in children, although it frequently goes unrecognized and untreated. This can have enormous negative consequences, particularly in children, since it is associated with numerous complications and comorbidities that have a significant health impact on quality of life. In fact, allergic rhinitis is considered to be a risk factor for asthma. There are numerous signs of allergic rhinitis, particularly in children, that can alert an observant clinician to its presence. Children with severe allergic rhinitis often have facial manifestations of itching and obstructed breathing, including a gaping mouth, chapped lips, evidence of sleep deprivation, a long face, dental malloclusions, and the allergic shiner, allergic salute, or allergic crease. The medical history is extremely important as it can reveal information regarding a family history of atopy and the progression of atopy in the child. It is also important to identify the specific triggers of allergic rhinitis, because one of the keys to successful management is the avoidance of triggers. A tripartite treatment strategy that embraces environmental control, immunotherapy, and pharmacologic treatment is the most comprehensive approach. Immunotherapy has come to be viewed as potentially prophylactic, capable of altering the course of allergic rhinitis. The most recent guidelines for the management of allergic rhinitis issued by the WHO recommend a tiered approach that integrates diagnosis and treatment, in which allergic rhinitis is subclassified both by frequency, as either intermittent or persistent, and by severity, as either mild or moderate to severe. Oral or topical antihistamines and intranasal corticosteroids are the mainstay of pharmacologic therapy for allergic rhinitis, depending upon its severity, and several agents have been approved for use in children aged 5 years old and younger.

Allergic rhinitis: systemic inflammation and implications for management

Allergic rhinitis triggers a systemic increase of inflammation. Within minutes of allergen exposure, immune cells release histamine, proteases, cysteinyl leukotrienes, prostaglandins, and cytokines. Some produce the early symptoms, while others augment the production, systemic circulation, and subsequent infiltration of the nasal mucosa with inflammatory cells that sustain the symptoms. Systemic circulation of inflammatory cells permits their infiltration into other tissues where chemoattractant and adhesion molecules already exist. Consequently, allergic rhinitis is linked to comorbid conditions: asthma, chronic hyperplastic eosinophilic sinusitis, nasal polyposis, and serous otitis media. Effective therapy should be directed at underlying inflammation and its systemic manifestations. It should improve the rhinitis and the comorbid conditions. Antihistamines relieve early symptoms by blocking basophil- and mast cell-generated histamine, but they do not significantly influence the pro-inflammatory loop. They are often little better than placebo. Oral corticosteroids provide the systemic anti-inflammatory efficacy, but their toxicity precludes such an approach. Intranasal corticosteroids effectively target the local inflammatory processes of rhinitis, reducing local inflammatory cells within the nares, but they do not directly access tissues involved in the comorbid conditions. Leukotriene modifiers have both systemic anti-inflammatory effects and an acceptable safety profile.

Efficacy and safety profile of fexofenadine HCl: a unique therapeutic option in H1-receptor antagonist treatment

Results of head-to-head comparative trials suggest that fexo-fenadine might offer distinct advantages compared with other antihistamines. Fexofenadine is highly selective for peripheral H(1)-receptors and does not cross the blood-brain barrier, as shown by positron emission tomography. These data support findings that fexofenadine is nonsedating and does not impair performance or driving ability, even at very high doses. In addition, fexofenadine does not interact with muscarinic receptors, which might offer a potential advantage compared with desloratadine, the recently approved active metabolite of loratadine. Fexofenadine is devoid of adverse cardiac effects, and changes in electrocardiogram parameters are not significantly different from those observed with placebo. Fexofenadine has also been shown to have a favorable effect on nasal congestion. This therapeutic advantage might be related to its significant antiallergic properties, ie, the demonstrated ability of fexofenadine to blunt the inflammatory effects of preformed and de novo synthesized mediators at clinically relevant doses in vivo and in vitro. Cumulatively, these benefits distinguish fexofenadine from other antihistamines and make it an optimum therapeutic option for treating allergy-mediated respiratory and dermatologic diseases.

Links between rhinitis and asthma

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

Overview of allergic rhinitis

BACKGROUND

Allergic rhinitis is the most common chronic condition seen in the outpatient practice of medicine. Its incidence is rising in parallel with other IgE-mediated diseases, affecting 10 to 30% of adults and up to 40% of children. Half the patients with allergic rhinitis experience symptoms up to 4 months per year, whereas 20% are symptomatic more than 9 months of the year. This disease is often associated with asthma, sinusitis, and otitis media.

OBJECTIVE

To review the literature concerning the evaluation and treatment of allergic rhinitis.

DATA SOURCES

Epidemiologic, pathophysiologic, and clinical studies published in peer-reviewed journals concerning the topic of allergic rhinitis.

RESULTS

Diagnosis of allergic rhinitis is based on patient history, signs and symptoms, physical examination, and appropriate testing procedures. Management includes aggressive environmental control measures to reduce exposure to implicated allergens, immunotherapy that can change the potential clinical course of allergic rhinitis by preventing the initiation and progression of airway inflammation, and pharmacotherapeutic management, including antihistamines and topical nasal corticosteroids.

CONCLUSIONS

Early recognition and management of allergic rhinitis, which include allergen avoidance, immunotherapy, and pharmacologic treatment, can prevent serious complications and significantly improve the patient's quality of life.

Allergic Rhinitis: Broader Disease Effects and Implications for Management

Allergic rhinitis is a burdensome disease for a significant part of the population in both adults and children. Poorly controlled allergic rhinitis can trigger exacerbations of asthma, sinusitis, and otitis media, diseases with which it shares common pathophysiologic elements. Consequently, early diagnosis and treatment should be a priority for patients and physicians, not only to control the symptoms of allergic rhinitis but also to improve the management of associated diseases. Several pharmacologic therapies can be considered in an armamentarium that includes antihistamines (intranasal and systemic), intranasal cromolyn, intranasal anticholinergic agents, intranasal steroids, systemic steroids, immunotherapy, and, most recently, leukotriene receptor antagonists. Often, combinations of these treatments are used to maximize control of refractory symptoms.

Comparative effects of desloratadine versus montelukast on asthma symptoms and use of beta 2-agonists in patients with seasonal allergic rhinitis and asthma

BACKGROUND

Asthma and seasonal allergic rhinitis (SAR) are recognized as manifestations of a single airway disease. Desloratadine has demonstrated efficacy in treating SAR symptoms, including nasal obstruction.

METHODS

Safety and efficacy of desloratadine and montelukast each were assessed in a double-blind, placebo-controlled trial of patients with SAR and symptoms of asthma, who were assigned randomly to once-daily treatment with desloratadine 5 mg, montelukast 10 mg, or placebo for 4 weeks. Change from baseline of AM/PM reflective total asthma symptom severity scores (TASS), FEV(1), individual asthma symptom scores, and beta(2)-agonist usage were assessed.

RESULTS

Desloratadine and montelukast each were associated with statistically significant reductions from baseline in the mean TASS averaged over the 4-week period (p < or =0.022 vs. placebo). Individual asthma symptom scores also improved significantly for both therapies (p < or = 0.05). Patients treated with desloratadine or montelukast demonstrated improvement from baseline in FEV(1) versus placebo; significant improvement was seen in a subset of patients with baseline FEV(1) <80% of predicted normal (both p < 0.05). Both active therapies significantly reduced beta(2)-agonist use (both p < 0.01). Improvements for both therapies were comparable for all efficacy parameters; they were tolerated well with adverse event profiles similar to placebo.

CONCLUSIONS

Asthma symptoms and beta(2)-agonist were improved significantly in patients with concomitant SAR and asthma treated with desloratadine 5 mg as well as montelukast 10 mg once daily. Both therapies significantly improved FEV(1) in a subset of patients with FEV(1) <80% of predicted normal at entry. Improvements in asthma symptoms were comparable for both active treatment groups.

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.

Bradykinin increases IL-8 generation in airway epithelial cells via COX-2-derived prostanoids

Interleukin (IL)-8, the C-X-C chemokine, is a potent neutrophil chemoattractant that has been implicated in a number of inflammatory airway diseases such as cystic fibrosis. Here we tested the hypothesis that bradykinin, an inflammatory mediator and chloride secretagogue, would increase IL-8 generation in airway epithelial cells through autocrine generation of endogenous prostanoids. Bradykinin increased IL-8 generation in both a non-cystic fibrosis (A549) and cystic fibrosis epithelial cell line (CFTE29) that was inhibited by the nonselective cyclooxygenase (COX) inhibitor indomethacin and the COX-2 selective inhibitor NS-398. COX-2 was the only isoform of COX expressed in both cell lines. Furthermore, the COX substrate arachidonic acid and exogenous prostaglandin E(2) both increased IL-8 release in A549 cells. These results suggest that bradykinin may contribute to neutrophilic inflammation in the airway by generation of IL-8 from airway epithelial cells. The dependence of this response on endogenous production of prostanoids by COX-2 suggests that selective COX-2 inhibitors may have a role in the treatment of airway diseases characterized by neutrophilic inflammation such as cystic fibrosis or chronic obstructive pulmonary disease.

Synergistic interactions between airway afferent nerve subtypes mediating reflex bronchospasm in guinea pigs

The hypothesis that airway afferent nerve subtypes act synergistically to initiate reflex bronchospasm in guinea pigs was addressed. Laryngeal mucosal application of capsaicin or bradykinin or the epithelial lipoxygenase metabolite 15(S)-hydroxyeicosatetraenoic acid evoked slowly developing but pronounced and sustained increases in tracheal cholinergic tone in situ. These reflexes were reversed by atropine and prevented by vagotomy, trimethaphan, or laryngeal denervation. Central nervous system-acting neurokinin receptor antagonists also abolished the reflexes without altering baseline cholinergic tone. Baseline tone was, however, reversed by disrupting pulmonary afferent innervation while preserving the innervation of the trachea and larynx. Surprisingly, selective pulmonary denervation also prevented the laryngeal capsaicin-induced tracheal reflexes, suggesting that laryngeal C-fibers act synergistically with continuously active intrapulmonary mechanoreceptors to initiate reflex bronchospasm. Indeed, reflex bronchospasm evoked by histamine was markedly potentiated by bradykinin, an effect mimicked by intracerebroventricular, but not intravenous, substance P. These data, as well as anatomic evidence for afferent nerve subtype convergence in the commissural nucleus of the solitary tract, suggest that airway nociceptors and mechanoreceptors may act synergistically to regulate airway tone.

Human eosinophils produce neurotrophins and secrete nerve growth factor on immunologic stimuli

Neurotrophins, such as nerve growth factor (NGF) and neurotrophin-3 (NT-3), are essential for development, function, and survival of peripheral sympathetic and sensory neurons. Most eosinophilic leukocytes in the human body are localized in mucosal tissues; however, the roles of eosinophils in human diseases are not fully understood. We found that human eosinophils constitutively express messenger RNA for NGF and NT-3, synthesize and store these proteins intracellularly, and continuously replenish them. Incubation of eosinophils with a transcription inhibitor, actinomycin D, for 8 hours completely depletes intracellular NGF and NT-3. New synthesis of NGF is enhanced by Fc-receptor-mediated stimuli, such as immunoglobulin (Ig)A and IgG immune complexes; in contrast, production of NT-3 is not affected by these stimuli. Notably, supernatants of eosinophils stimulated with IgA immune complex and interleukin 5 promote neurite extension of the PC-12 pheochromocytoma cell line; this effect is abolished by pretreatment of the supernatants with anti-NGF-neutralizing antibody. By enzyme-linked immunosorbent assay, substantial amounts of NGF protein are also detected in the supernatants of stimulated eosinophils. Furthermore, in patients with seasonal allergic rhinitis, the concentrations of NGF in nasal secretions correlate with the magnitudes of eosinophilic inflammation in the airway, suggesting a potential clinical implication of eosinophil NGF. Our observations propose a new pathologic mechanism by which eosinophils may contribute to enhanced neurologic responses in patients with allergic diseases and other eosinophilic disorders. Alternatively, eosinophils may play important roles in maintenance and restoration of homeostatic functions of mucosal tissues through the pleitropic activities of NGF.

Allergic rhinitis in children

Epidemiologic and pathophysiologic evidence indicates that allergic rhinitis, whether seasonal or perennial, is one piece of a larger atopic clinical picture that often occurs concomitantly with asthma. Allergic rhinitis usually develops during childhood and has a prevalence of up to 40% in the pediatric population. Careful attention to food allergies and the presence of household allergens during infancy and early childhood may limit potential sensitizations. Many antihistamines and topical corticosteroids now are available for the treatment of allergic rhinitis in children, which is all the more important because optimal management may improve quality of life and curtail the development of serious sequelae.

Allergic rhinitis and asthma in children: disease management and outcomes

Antihistamines and inhaled glucocorticoids, which can be targeted toward multiple points in the "allergic cascade" underlying allergic rhinitis and asthma, extend the promise of enhanced outcomes in children with allergic rhinitis, asthma, or both. Antihistamine therapy confers significant relief of subjective ratings of seasonal and perennial allergic symptoms (e.g., rhinorrhea, congestion, sneezing, pruritus), whereas topical steroids alleviate such discomfort while also improving objective anatomic and functional indices of nasal patency (e.g., nasal peak inspiratory flow). Youngsters with asthma also experience substantial clinical benefits from inhaled steroids, which improve objective measures of pulmonary function and reduce rescue beta 2-agonists for symptom management and quality-of-life enhancement. This paper reviews recent clinical findings on the role of antihistamines and topical corticosteroids in pediatric allergy and asthma management, as well as the favorable effects of these medications on both objective and subjective health outcomes.

Desloratadine activity in concurrent seasonal allergic rhinitis and asthma

Seasonal allergic rhinitis (SAR) and asthma, which are frequently comorbid, share some common allergic pathogenic bases. Clinical manifestations of these disorders might therefore be viewed as local manifestations of a systemic inflammatory state. Not only do the onsets of allergic-rhinitis (AR) and asthma symptoms often coincide (within 1 year), but also nasal challenges with SAR allergens can induce airways hyperreactivity (AHR). Eosinophils, which are key effector cells in both SAR and asthma, cause AHR, tissue damage, and neuronal effects through secretion of toxic granule proteins, enzymes, and other mediators. The novel, nonsedating, histamine H1-receptor antagonist, desloratadine, which exerts various favorable effects on the allergic cascade, significantly decreased SAR symptoms (e.g., nasal congestion) and diminished daily beta2-agonist use and improved asthma symptoms, while maintaining pulmonary function, in patients with SAR-asthma who were treated with once-daily desloratadine regimens.

Effect of pollutants in rhinitis

Allergic rhinitis is a very common disease worldwide and is influenced by both genetic and environmental factors. Exposure to environmental allergens is the most significant environmental factor in development and exacerbation of allergic rhinitis. However, air pollutants that are not allergens may affect allergic inflammation in the nasal airway. The nasal airway possesses a number of defense mechanisms to deal with environmental irritants. This article examines the effect of ozone and particulate air pollution of TH2-type inflammation in the airway and how nasal defenses protect the upper and lower airway from adverse effects of pollutants.