Introduction to nasal and pulmonary allergy cascade

Could FeNO Predict Asthma in Patients with House Dust Mites Allergic Rhinitis?

Background and Objectives: The evolution of allergic rhinitis to asthma is a part of "atopic march". The aim of this study was to analyze possible predictive markers for asthma occurrence in patients with allergic rhinitis to house dust mites (HDM). Materials and Methods: Fifty-eight patients with persistent allergic rhinitis (PAR) were included. The clinical, biological evaluation and fractionated exhaled nitric oxide (FeNO) measurement were performed at enrolment. The patients were clinically evaluated after one year to determine asthma occurrence. Results: The severity of rhinitis symptoms, levels of total immunoglobulin E (IgE), ICAM-1, VCAM-1, E-selectin and IL-6, but not IL-8 and TNF-α were higher in patients with allergic rhinitis who developed asthma compared to non-asthmatics, but the differences were not significant to considered them as predictive factors for asthma occurrence. The risk of asthma was independently influenced by patients aged over 30 years ((OR-3.74; CI95% 0.86-16.31; p = 0.07), a duration of allergic rhinitis over 12 months ((OR-4.20; CI95% 0.88-20; p = 0.07) and a basal FeNO over 28 parts per billion (pbb) ((OR-18.68; CI95% 3.79-92.05; p < 0.001). Conclusion: Clinical and biological parameters may predict asthma occurrence in patients with persistent allergic rhinitis to HDM. Adult patients with a longer duration of rhinitis symptoms and a high level of FeNO have a greater risk to develop asthma.

Natural killer cells in patients with allergic diseases

Natural killer (NK) cells not only exert cytotoxic activity against tumor cells or infected cells but also act to regulate the function of other immune cells through secretion of cytokines and chemokines or cell contact-dependent mechanisms. NK cells are able to polarize in vitro into 2 functional distinct subsets, NK1 or NK2 cells, which are analogous to the T-cell subsets TH1 or TH2. In addition, a regulatory NK cell subset has been described that secretes IL-10, shows antigen-specific T-cell suppression, and suppresses IgE production. Although it has been demonstrated that NK cells play important roles in autoimmunity, cancer, transplantation, and pregnancy, the role of NK cells in allergy has not been extensively discussed. This review aims to discuss our understanding of NK cells and NK cell subsets in allergic inflammation and IgE regulation.

Local and systemic IgE in the evaluation and treatment of allergy

Traditional descriptions of type I hypersensitivity and its manifestations center on systemic immunoglobulin E (IgE)-mediated reactions to inciting antigens. Hence, many current diagnostic and therapeutic measures are based on systemic skin testing for allergy, systemic pharmacotherapy, and immunotherapy. Recent developments in rhinology and pulmonology, particularly in defining the phenomenon of local IgE production in various airway inflammatory conditions, have an impact on both medical and surgical diagnosis and management of these conditions. This review includes a discussion of allergy as a systemic disease, current systemic diagnostic and management strategies for allergy, and local IgE presence and synthesis in the upper and lower airways.

Ultra-short course immunotherapy in children and adolescents during a 3-yrs post-marketing surveillance study

Ultra-short course immunotherapy (uSCIT) has shown good efficacy and tolerability in children and adolescents with seasonal allergic rhinitis (SAR), conjunctivitis and/or asthma in clinical studies. Here, we investigate the efficacy of uSCIT in the juvenile subpopulation of a 3-year post-marketing surveillance (PMS) study. To assess the differences in the efficacy of uSCIT between adults and children respectively adolescents enrolled in a PMS study. In a prospective open study 422 patients aged 6-18 years with SAR, conjunctivitis and/or asthma received four pre-seasonal injections with pollen allergoids formulated with monophosphoryl lipid A (MPL, Pollinex Quattro) over a minimum of 3 weeks. Efficacy was evaluated by response to therapy and consumption of anti-allergic medication during the pollen season. Tolerability was evaluated by patients' acceptance of therapy. These results were compared with the adult subpopulation of this study. Response to treatment was assessed as good or very good in 94% of patients, mirroring findings for the entire cohort. Further improvements were noted in patients receiving subsequent courses of therapy. Anti-allergic medication use decreased from 83% to 24% of patients after the first treatment course (p < 0.0001). Therapy was well accepted by children/adolescents and considered 'very good' or 'good' by 93% of juveniles. No serious adverse events or cases of anaphylaxis were reported. This subanalysis indicated that uSCIT with Pollinex Quattro had similar efficacy and tolerability in children/adolescents and adults. The convenient dosing regimen and favourable safety profile of uSCIT may support a wider uptake of uSCIT in this patient population.

Minimal persistent inflammation in allergic rhinitis: implications for current treatment strategies

Patients with allergic rhinitis have traditionally been placed into 'seasonal' and 'perennial' categories, which do not account for the subclinical inflammatory state that exists in many patients. In subjects with seasonal and perennial allergic rhinitis, even subthreshold doses of allergen have been found to cause inflammatory cell infiltration in the nasal mucosa, including increases in expression of cellular adhesion molecules, nasal and conjunctival eosinophilia, and other markers of inflammation, which do not result in overt allergy symptoms. This state - which has been termed 'minimal persistent inflammation'- may contribute to hyperreactivity and increased susceptibility to development of clinical symptoms as well as common co-morbidities of allergic rhinitis, such as asthma. Treating overt allergy symptoms as well as this underlying inflammatory state requires agents that have well-established clinical efficacy, convenient administration, potent anti-inflammatory effects and proven long-term safety, so that long-term continuous administration is feasible. Of the three major classes of commonly used allergic rhinitis medications - intranasal corticosteroids, anti-histamines, and anti-leukotrienes - intranasal corticosteroids appear to represent the most reasonable therapeutic option in patients who would benefit from continuous inhibition of persistent inflammation.

Ebastine in allergic rhinitis and chronic idiopathic urticaria

Histamine is a key mediator in the development of allergy symptoms, and oral H(1)-antihistamines are among the most widely used treatments for symptomatic relief in conditions such as allergic rhinitis and chronic urticaria. Ebastine is a second-generation antihistamine which has been shown to be an effective treatment for both seasonal and perennial allergic rhinitis. In controlled clinical trials in adult and adolescent patients with allergic rhinitis, ebastine 10 mg once-daily improved symptoms to a significantly greater extent than placebo and to a similar extent as loratadine 10 mg and cetirizine 10 mg (both once-daily), while ebastine 20 mg proved to be more effective than these two comparator antihistamines. In addition, ebastine was significantly more effective than placebo at relieving the symptoms of chronic idiopathic urticaria. Ebastine provides efficacy throughout the 24-h dosing interval with once-daily administration and clinical benefit is seen from the first day of treatment. Small studies have found beneficial effects for ebastine in patients with other disorders, including cold urticaria, dermographic urticaria, atopic asthma, mosquito bites and (in combination with pseudoephedrine) the common cold. In addition to the regular ebastine tablet, a fast-dissolving tablet (FDT) formulation, which disintegrates in the mouth without the aid of a drink, is also available. It has been shown to be bioequivalent to the regular tablet, and to be significantly more effective than desloratadine at reducing histamine-induced cutaneous wheals. A number of patient surveys demonstrated that the majority of individuals who tried the fast-dissolving formulation reported it to be convenient for use, fast-acting and preferred it to their previous antihistamine medication. Perhaps most importantly, a large proportion of patients indicated that they would prefer to use this new formulation in the future. Ebastine has a rapid onset of action and it can be administered once-daily, with or without food. Dose modifications are not needed in elderly patients, or in those with renal or mild to moderate hepatic impairment. Ebastine is generally well-tolerated, and clinical studies showed that at usual therapeutic doses of 10 and 20 mg once-daily, it had no clinically relevant adverse effects on cognitive function and psychomotor performance or on cardiovascular function. In conclusion, ebastine is an effective and generally well-tolerated treatment for allergic rhinitis and chronic idiopathic urticaria. In addition to the regular tablet formulation, ebastine is available as a FDT, providing a treatment option that is particularly convenient for patients.

Perturbations of natural killer cell regulatory functions in respiratory allergic diseases

BACKGROUND

Allergic diseases are characterized by abnormal responses to allergens favored by an inappropriate regulation of the T(H)1-T(H)2 polarization. Natural killer (NK) cells give rise to a complex NK/dendritic cell (DC) cross-talk that would help T(H)1 responses.

OBJECTIVE

By analyzing peripheral blood NK cells from 12 patients with either allergic rhinitis or rhinitis and intermittent asthma, we evaluated whether these cells were impaired in their ability to interact with DCs.

METHODS

Different circulating NK cell subsets were analyzed by flow cytofluorimetry. Mixed NK/DC cultures were performed to assess the reciprocal functional interactions. NK cells were analyzed for their ability to induce DC maturation and cytokine production, and to kill immature DCs. In addition, DCs were assessed for their ability to induce cytokine production by NK cells.

RESULTS

We first analyzed the CD56++CD16+/- cells, a subset of circulating NK cells that is able to respond to DCs by proliferating and producing IFN-gamma. Our analysis revealed that this NK cell subpopulation was significantly reduced in most patients. This was reflected by reduced NK cell-mediated IFN-gamma production in response to DCs. Also, the capability of promoting DC maturation and/or killing immature DCs, a function sustained by CD56+CD16+ NK cells, was reduced in most patients.

CONCLUSIONS

We suggest that allergic diseases are accompanied by a partial impairment of the NK cell capability of promoting and maintaining appropriate T(H)1 responses.

Efficacy of desloratadine in the treatment of allergic rhinitis: a meta-analysis of randomized, double-blind, controlled trials

The objective of the study is to assess the efficacy of the nonsedating antihistamine, desloratadine, in the treatment of allergic rhinitis (AR). A search of MEDLINE, EMBASE, LILACS, and CINAHL databases was undertaken from January, 1966 to May, 2006. Double-blind, randomized, controlled studies of desloratadine in the treatment of AR in adult patients were carried out. The measured outcomes included the total symptoms score, the total nasal symptoms score, nasal airflow, and inflammatory markers (nasal eosinophils, nasal interleukin-4). The analysis included the calculation of standardized mean difference (SMD). A total of 57 studies were analyzed, and 13 randomized, double-blind, controlled trials were included in the meta-analysis. The trials included 3108 subjects who had completed studies involving desloratadine. There was significant heterogeneity among the study results, because of differing study methodologies. Desloratadine was associated with significant reductions in total symptoms scores (SMD -1.63; 95% CI -2.75 to -0.51; P = 0.004) and total nasal symptoms score (SMD -0.66; 95% CI -0.91 to -0.42; P < 0.001), when compared with placebo. Analysis of objective data on nasal blockage demonstrated a significant improvement in nasal airflow with desloratadine, when compared with placebo (SMD 0.32; 95% CI 0.10 to 0.55; P = 0.005). A benefit favoring desloratadine over placebo in terms of nasal eosinophil levels was also noted in the analysis. This meta-analysis confirms the reduction of AR symptoms and improvement in nasal airflow seen in individual studies of desloratadine. Objective improvements in nasal airflow, total symptoms, and total nasal symptoms seen with desloratadine are supported by Ia evidence.

Pathophysiology of nasal obstruction and meta-analysis of early and late effects of levocetirizine

Nasal obstruction, also referred to as congestion, blockage or stuffiness, is a crucial symptom in allergic rhinitis (AR) and may affect sleep as well as quality of life. Early- and late-phase-allergic reactions both contribute to nasal obstruction, although it primarily represents a major symptom in the chronic allergic reaction. A complex network of inflammatory and neurogenic phenomena relates to chronic nasal obstruction, including the subepithelial accumulation of inflammatory cells, particularly mast cells and eosinophils, and the release of neuropeptides. Nasal obstruction is a difficult-to-treat symptom. Vasoconstrictors (decongestants) and intranasal corticosteroids, due to their anti-inflammatory properties, have mainly been used for relieving the nasal passages from the congested mucosa. However, there is accumulating evidence recently that the latest-generation potent antihistamines have decongestant properties in AR. This paper aims to review the pathophysiologic background of nasal obstruction and the evidence for an antihistamine, levocetirizine, in relieving nasal congestion. A meta-analysis on the early and late effects of levocetirizine on nasal obstruction under artificial and natural allergen exposure conditions is presented, demonstrating convincingly that levocetirizine shows a consistent effect on nasal obstruction as early as over the first 2 h and sustained over 6 weeks.

Association between allergic rhinitis and hospital resource use among asthmatic children in Norway

BACKGROUND

Preliminary evidence suggests that inadequately controlled allergic rhinitis in asthmatic patients can contribute towards increased asthma exacerbations and poorer symptom control, which may increase medical resource use. The objective of this study was therefore to assess the effect of concomitant allergic rhinitis on asthma-related hospital resource utilization among children below 15 years of age with asthma in Norway.

METHODS

A population-based retrospective cohort study of children (aged 0-14 years) with asthma was conducted using data from a patient-specific public national database of hospital admissions during a 2-year period, 1998-1999. Multivariate linear regression, adjusting for risk factors including age, gender, year of admission, urban/rural residence and severity of asthma episode, estimated the association between allergic rhinitis and total hospital days. A multivariate Cox proportional-hazards model estimated relative hazard of readmission according to concomitant allergic rhinitis status.

RESULTS

Among 2961 asthmatic children under 15 years of age with at least one asthma-related hospital admission over a 2-year period, 795 (26.8%) had a recorded history of allergic rhinitis. Asthmatic children with allergic rhinitis had a 1.72-times greater hazard of asthma-related readmissions than asthmatic children without allergic rhinitis. Multivariate analysis revealed that history of concomitant allergic rhinitis was a significant predictor of increased number of hospital days per year (least-squares mean difference 0.23 days, P < 0.05).

CONCLUSIONS

Concomitant allergic rhinitis in asthmatic children was associated with increased likelihood of asthma-related hospital readmissions and greater total hospital days.

Use of mouse models of allergic rhinitis to study the upper and lower airway link

PURPOSE OF REVIEW

Allergic rhinitis and asthma are examples of a continuum of airway diseases with diverse clinical manifestations. This review examines the most recent work in mouse models studying upper and lower airway links and interactions.

RECENT FINDINGS

The concept of united airways has been supported by investigative and epidemiological studies. Studies using mouse models of asthma and models of allergic rhinitis have demonstrated that analogous pathways lead to inflammation and airway hyperresponsiveness. Th2-type T cells and IL-13 play important immunopathologic roles. Recent studies have examined upper airway mucosal immune responses and development of both allergic and tolerant phenotypes. In a model of allergic airways disease, there is evidence of lower airway inflammation and airways hyperresponsiveness following application of allergen only to the nares, suggesting local stimulation can activate distal allergic responses. Immunomodulatory properties of the airway mucosa have also been explored. Allergen-specific tolerance can be induced by appropriate stimulation of airway mucosa and is associated with activation of IL-10-producing T cells. This effect is mediated by antigen presenting cells, especially dendritic cells.

SUMMARY

Immune stimulation of the airway mucosa, both in the upper and lower airways, results in active T-cell-mediated immune responses leading toward tolerance or asthma and allergic rhinitis. Regulation of these T-cell responses is currently under investigation. It is clear from these studies that antigenic stimulation of any part of the respiratory mucosa can have ripple effects along the entire airway and supports the concept of united airways.

Glucocorticoid receptors in human airways

Inhaled and intranasal glucocorticoids are the most common and effective drugs for controlling symptoms and airway inflammation in respiratory diseases such as asthma, allergic rhinitis, and nasal polyposis. The last few years have seen a growing understanding of the mechanisms of glucocorticoid action and, in particular, the receptor that mediates glucocorticoid actions, the glucocorticoid receptor (GR). In this revision we present an update on the GR gene, the expression and regulation of its gene products, namely GRalpha and GRbeta, as well as their alterations in pathological states. GRalpha is responsible for the induction and repression of target genes, it is expressed in virtually all human cells and tissues, and its expression is known to be downregulated by glucocorticoids. GRbeta has been found to act as a dominant negative inhibitor of GRalpha-mediated transactivation in in vitro studies with transfected cells, but it does not appear to have a significant inhibitory effect on GRalpha-mediated transrepression. In addition, for most tissues the expression of GRbeta, at least at the mRNA level, is extremely low compared with that of GRalpha. Some pro-inflammatory cytokines appear to upregulate the expression of GRbeta, and increased GRbeta expression has been reported in diseases associated with glucocorticoid resistance or insensitivity, such as bronchial asthma, nasal polyposis, and ulcerative colitis. However, the possible role of GRbeta in modulating glucocorticoid sensitivity and/or resistance in vivo has been highly debated and it is not yet clear.

In vivo conjugation of nasal lavage proteins by hexahydrophthalic anhydride

Hexahydrophthalic anhydride (HHPA), an industrially important chemical, is a highly allergenic compound. The aim of this work was to identify proteins in nasal lavage fluid (NLF) that form adducts with HHPA. Such bindings may induce production of specific immunoglobulin E (IgE) or affect physiological mechanisms of the proteins. NLF was obtained from HHPA-exposed volunteers, workers and exposed guinea pigs. HHPA-binding proteins were visualized with immunoblotting using a polyclonal antiserum against HHPA. The proteins were excised from sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, digested with trypsin and identified by tandem mass spectrometry (MS/MS) and database searches. The antiserum was found to be specific for HHPA-bound proteins. In vivo formed HHPA-binding proteins in humans were identified as antileukoproteinase, immunoglobulin G (IgG), immunoglobulin A (IgA), serum albumin and lactoferrin. In addition, several proteins binding to HHPA were found in NLFs from guinea pigs but these could not be identified from database searches. Hypotheses for development of airways diseases by adduction of this allergenic compound to the NLF proteins in humans were established.

Advances in allergy management

Our understanding of the pathophysiology of allergy has moved to the molecular level, while study of epidemiology and genetics has revealed risks of developing allergies based on environmental and genetic profiles, and pharmacoeconomic data have enabled accurate measurement of the immense burden of allergic disease. These advances in allergy research have affected its management, particularly the search for new antiallergy therapies. New therapies should intervene in the systemic allergy inflammatory cascade and provide clinical efficacy that extends to multiple allergic disease states. In addition, these new therapies should present no additional safety issues, offer improvements over existing therapies, and have an impact on disease-impaired quality of life. In vitro studies show that desloratadine, a new, once-daily, nonsedating, selective histamine H1-receptor antagonist, blocks the systemic allergy cascade at multiple points. Desloratadine 5 mg once daily relieves the symptoms of chronic idiopathic urticaria and of both seasonal (SAR) and perennial allergic rhinitis. In patients with concomitant asthma and SAR, asthma symptoms are relieved and beta2-agonist medication use is decreased by desloratadine. Unlike many other second-generation histamine H1-receptor antagonists, desloratadine provides the added benefit of efficacy against nasal obstruction in SAR. Desloratadine improves quality of life by decreasing the impact of allergic symptoms on sleep and on daily activities.

Impact and modulation of nasal obstruction

Nasal obstruction, the leading symptom of allergic rhinitis, results from the combined activity of early- and late-phase allergic reactions. Desloratadine inhibits both early- and late-phase inflammatory mediators in vitro. Thus, double-blind, placebo-controlled, randomized, crossover trials were conducted to assess the efficacy of desloratadine against nasal obstruction, measured objectively and subjectively, during controlled exposure of patients with seasonal allergic rhinitis to allergen. Positive results were obtained in three single-dose studies; desloratadine 5 mg resulted in a greater improvement from baseline than did placebo in the total symptom score and the nasal obstruction symptom score (P </= 0.02). Desloratadine was more effective than placebo in a multiple-dose study; desloratadine 5 mg was given once daily for 7 days, and a 6-h allergen challenge was administered at the end of treatment compared with placebo. Desloratadine treatment was associated with less deterioration from baseline in the mean nasal airflow (P < 0.05) and in the mean severity score for the symptom of nasal obstruction (P < 0.03). Desloratadine significantly reduces the severity of nasal obstruction in patients with seasonal allergic rhinitis.