Selective release of miRNAs via extracellular vesicles is associated with house-dust mite allergen-induced airway inflammation

BACKGROUND

MicroRNAs (miRNAs) may facilitate cell-to-cell communication via extracellular vesicles (EVs). The biological roles of miRNAs in EVs on allergic airway inflammation are unclear.

METHODS

Airway-secreted EVs (AEVs) were isolated from bronchoalveolar lavage fluid (BALF) of control and house-dust mite (HDM) allergen-exposed HDM-sensitized mice. The expression of miRNAs in AEVs or miRNAs and mRNAs in lung tissue was analysed using miRNA microarray.

RESULTS

The amount of AEV increased 8.9-fold in BALF from HDM-exposed mice compared with that from sham-control mice. HDM exposure resulted in significant changes in the expression of 139 miRNAs in EVs and 175 miRNAs in lung tissues, with 54 miRNAs being common in both samples. Expression changes of these 54 miRNAs between miRNAs in AEVs and lung tissues after HDM exposure were inversely correlated. Computational analysis revealed that 31 genes, including IL-13 and IL-5Ra, are putative targets of the miRNAs up-regulated in AEVs but down-regulated in lung tissues after HDM exposure. The amount of AEV in BALF after HDM exposure was diminished by treatment with the sphingomyelinase inhibitor GW4869. The treatment with GW4869 also decreased Th2 cytokines and eosinophil counts in BALFs and reduced eosinophil accumulation in airway walls and mucosa.

CONCLUSION

These results indicate that selective sorting of miRNA including Th2 inhibitory miRNAs into AEVs and increase release to the airway after HDM exposure would be involved in the pathogenesis of allergic airway inflammation.

Weight Gain Alters Adiponectin Receptor 1 Expression on Adipose Tissue-Resident Helios+ Regulatory T Cells

Adipose tissue produces multiple mediators that modulate the immune response. Adiponectin is an adipocyte-derived cytokine that exhibits metabolic and anti-inflammatory effects. Adiponectin acts through binding to adiponectin receptor 1 and 2 (AdipoR1/AdipoR2). AdipoR1 is ubiquitously expressed, whereas AdipoR2 is restricted to skeletal muscle and liver. AdipoR1 expression has been reported on a small percentage of T cells; nevertheless, it is still unknown whether Foxp3(+) regulatory T cells (Tregs) express AdipoR1. Recently, it has been shown that Tregs accumulate in adipose tissue and that they play a potential role in modulating adipose tissue inflammation. Our aim was to evaluate AdipoR1 expression in adipose tissue-resident Tregs and to evaluate the effect of weight gain on this expression. Male C57BL/6 mice were fed with a high-fat diet for 14 weeks (to develop overweight) or 21 weeks (to develop obesity). Mice on a standard diet were used as age-matched controls. Helios expression was evaluated as a marker to discriminate thymic-derived from peripherally induced Tregs. The majority of Tregs in both adipose tissue and the spleen expressed Helios. Adipose tissue Tregs expressed higher levels of AdipoR1 than Tregs in the spleen. AdipoR1 expression on adipose tissue Helios(+) Tregs was negatively correlated with epididymal fat. Overall, we show that AdipoR1 is expressed on adipose tissue-resident Tregs, mainly Helios(+) Tregs, and that this expression is dependent on weight and fat accumulation. Because both adiponectin and Tregs play roles in anti-inflammatory mechanisms, our data propose a new mechanism through which weight gain might alter immunoregulation.

Increase in pollen sensitization in Swedish adults and protective effect of keeping animals in childhood

BACKGROUND

To date, most studies of the 'allergy epidemic' have been based on self-reported data. There is still limited knowledge on time trends in allergic sensitization, especially among adults.

OBJECTIVE

To study allergic sensitization, its risk factors and time trends in prevalence.

METHODS

Within West Sweden Asthma Study (WSAS), a population-based sample of 788 adults (17-60 years) underwent skin prick tests (SPTs) for 11 aeroallergens 2009-2012. Specific IgE was analysed in 750 of the participants. Those aged 20-46 years (n = 379) were compared with the European Community Respiratory Health Survey sample aged 20-46 year from the same area (n = 591) in 1991-1992.

RESULTS

Among those aged 20-46 years, the prevalence of positive SPT to pollen increased, timothy from 17.1% to 29.0% (P < 0.001) and birch from 15.6% to 23.7% (P = 0.002) between 1991-1992 and 2009-2012. Measurements of specific IgE confirmed these increases. Prevalence of sensitization to all other tested allergens was unchanged. In the full WSAS sample aged 17-60 years, any positive SPT was seen in 41.9%, and the dominating sensitizers were pollen (34.3%), animals (22.8%) and mites (12.6%). Pollen sensitization was strongly associated with rhinitis, whereas indoor allergens were more associated with asthma. Growing up with livestock or furred pets decreased the risk of sensitization, adjusted odds ratio 0.53 (0.28-0.995) and 0.68 (0.47-0.98), respectively.

CONCLUSION

Pollen sensitization has increased in Swedish adults since the early 1990s, while the prevalence of sensitization to other allergens has remained unchanged. This is one plausible explanation for the increase in rhinitis 1990-2008 in Swedish adults, during which time the prevalence of asthma, which is more associated with perennial allergens, was stable. Contact with animals in childhood seems to reduce the risk of sensitization well into adulthood. One major factor contributing to the rise in pollen allergy is a significant increase in levels of birch and grass pollen over the past three decades.

Aspirin-intolerant asthma in the population: prevalence and important determinants

BACKGROUND

Population-based studies on aspirin-intolerant asthma (AIA) are very few, and no previous population study has investigated risk factors for the condition.

OBJECTIVE

To investigate the prevalence and risk factors of AIA in the general population.

METHODS

A questionnaire on respiratory health was mailed to 30,000 randomly selected subjects aged 16-75 years in West Sweden, 29,218 could be traced and 18,087 (62%) responded. The questionnaire included questions on asthma, respiratory symptoms, aspirin-induced dyspnoea and possible determinants.

RESULTS

The prevalence of AIA was 0.5%, 0.3% in men and 0.6% in women (P = 0.014). Sick leave, emergency visits due to asthma and all investigated lower respiratory symptoms were more common in AIA than in aspirin-tolerant asthma (ATA). Obesity was a strong risk factor for AIA (BMI > 35: odds ratio (OR) 12.1; 95% CI 2.49-58.5), and there was a dose-response relationship between increasing body mass index (BMI) and risk of AIA. Obesity, airborne occupational exposure and visible mould at home were considerably stronger risk factors for AIA than for ATA. Current smoking was a risk factor for AIA (OR 2.55; 95% CI 1.47-4.42), but not ATA.

CONCLUSION

Aspirin-intolerant asthma identified in the general population was associated with a high burden of symptoms, uncontrolled disease and a high morbidity. Increasing BMI increased the risk of AIA in a dose-response manner. A number of risk factors, including obesity and current smoking, were considerably stronger for AIA than for ATA.

Once-daily fluticasone furoate 50 mcg in mild-to-moderate asthma: a 24-week placebo-controlled randomized trial

BACKGROUND

Inhaled glucocorticosteroids (ICS) are the mainstay of treatment in asthma. Fluticasone furoate (FF) is a novel, once-daily ICS asthma therapy. This study investigated the efficacy and safety of FF 50 mcg in patients with mild-to-moderate persistent asthma.

METHODS

A 24-week, multicenter, randomized, placebo-controlled and active-controlled, double-blind, double-dummy, parallel-group phase III study. Three hundred and fifty-one patients (aged ≥12 years; uncontrolled by non-ICS therapy) were randomized to treatment (1 : 1 : 1) with once-daily FF 50 mcg dosed in the evening, twice-daily fluticasone propionate (FP) 100 mcg or placebo. The primary endpoint was change from baseline in evening trough forced expiratory volume in 1 s (FEV1 ) at Week 24. Secondary endpoints were change from baseline in the percentage of rescue-free 24-h periods (powered endpoint), change from baseline in evening and morning peak expiratory flow, change from baseline in the percentage of symptom-free 24-h periods and number of withdrawals due to lack of efficacy.

RESULTS

Evening trough FEV1 at Week 24 was not statistically significantly increased with FF 50 mcg once-daily (37 ml [95% CI: -55, 128]; P = 0.430), but was with FP 100 mcg twice daily (102 ml [10, 194]; P = 0.030), vs placebo. No consistent trends were observed across other endpoints, including the powered secondary endpoint. No safety concerns were raised for either active treatment.

CONCLUSIONS

FP 100 mcg twice daily improved evening trough FEV1 in patients with mild-to-moderate persistent asthma, but FF 50 mcg once daily did not demonstrate a significant effect. Secondary endpoints showed variable results. No safety concerns were identified for FF or FP.

Economic burden of inadequate management of allergic diseases in the European Union: a GA(2) LEN review

BACKGROUND

In the European Union (EU), between 44 and 76 million individuals of the 217 million EU employees suffer from allergic disease of the airways or the skin. Up to 90% of these persons are untreated or insufficiently treated. This has major socio-economic consequences such as absence from work (absenteeism), particularly reduced productivity at work (presenteeism).

METHODS

We used published literature and online statistical information from Eurostat and Eurofound to assess the costs of allergic disease to society.

RESULTS

Allergies have an impact on direct, indirect, intangible and opportunity costs. Most importantly, for the EU, avoidable indirect costs per patient insufficiently treated for allergy range between €55 and €151 billion per annum due to absenteeism and presenteeism, that is, €2405 per untreated patient per year. On the other hand, appropriate therapy for allergic diseases is available at comparatively low costs at an average of €125 per patient annually, equalling only 5% of the costs of untreated disease, allowing potential savings of up to €142 billion.

CONCLUSIONS

A better care for allergies based on guideline-based treatment would allow Europe's economy substantial savings. In addition, allergies have an impact on learning and performance at school and university, leading to opportunity costs for society. This cannot be calculated moneywise but will have an impact in a modern knowledge-based society. Still allergies are trivialized in society, noting that the costs of therapy are paid by patients and healthcare services, whereas economic savings are made by employers and society. A change of this mindset is urgently needed.

Geographical variation in the prevalence of sensitization to common aeroallergens in adults: the GA(2) LEN survey

BACKGROUND

Geographical variation in the prevalence of sensitization to aeroallergens may reflect differences in exposure to risk factors such as having older siblings, being raised on a farm or other unidentified exposures.

OBJECTIVE

We wanted to measure geographical variation in skin prick test positivity and assess whether it was explained by differences in family size and/or farm exposure. We also compared prevalence in younger and older subjects.

METHODS

Within the Global Allergy and Asthma European Network (GA(2) LEN) survey, we measured the prevalence of skin prick positivity to a panel of allergens, and geometric mean serum total immunoglobulin E (IgE), in 3451 participants aged 18-75 years in 13 areas of Europe. Estimated prevalence was standardized to account for study design. We compared prevalence estimates in younger and older subjects and further adjusted for age, gender, smoking history, farm exposure, number of older siblings and body mass index (BMI).

RESULTS

Skin prick test positivity to any one of the measured allergens varied within Europe from 31.4% to 52.9%. Prevalence of sensitization to single allergens also varied. Variation in serum total IgE was less marked. Younger participants had higher skin prick sensitivity prevalence, but not total IgE, than older participants. Geographical variation remained even after adjustment for confounders.

CONCLUSION

Geographical variation in the prevalence of skin prick test positivity in Europe is unlikely to be explained by geographical variation in gender, age, smoking history, farm exposure, family size and BMI. Higher prevalence in younger, compared to older, adults may reflect cohort-associated increases in sensitization or the influence of ageing on immune or tissue responses.

EAACI position statement on asthma exacerbations and severe asthma

Asthma exacerbations and severe asthma are linked with high morbidity, significant mortality and high treatment costs. Recurrent asthma exacerbations cause a decline in lung function and, in childhood, are linked to development of persistent asthma. This position paper, from the European Academy of Allergy and Clinical Immunology, highlights the shortcomings of current treatment guidelines for patients suffering from frequent asthma exacerbations and those with difficult‐to‐treat asthma and severe treatment‐resistant asthma. It reviews current evidence that supports a call for increased awareness of (i) the seriousness of asthma exacerbations and (ii) the need for novel treatment strategies in specific forms of severe treatment‐resistant asthma. There is strong evidence linking asthma exacerbations with viral airway infection and underlying deficiencies in innate immunity and evidence of a synergism between viral infection and allergic mechanisms in increasing risk of exacerbations. Nonadherence to prescribed medication has been identified as a common clinical problem amongst adults and children with difficult‐to‐control asthma. Appropriate diagnosis, assessment of adherence and other potentially modifiable factors (such as passive or active smoking, ongoing allergen exposure, psychosocial factors) have to be a priority in clinical assessment of all patients with difficult‐to‐control asthma. Further studies with improved designs and new diagnostic tools are needed to properly characterize (i) the pathophysiology and risk of asthma exacerbations, and (ii) the clinical and pathophysiological heterogeneity of severe asthma.

Modulation of allergen-induced bronchoconstriction by fluticasone furoate and vilanterol alone or in combination

BACKGROUND

This placebo-controlled study assessed the effects of the once-daily inhaled corticosteroid (ICS) fluticasone furoate (FF) and long-acting beta(2) -agonist (LABA) vilanterol (VI) on early and late asthmatic responses (EAR/LAR) and airway hyper-responsiveness (AHR).

METHODS

Patients (n = 27) were randomized to FF (100 μg), VI (25 μg), FF/VI (100/25 μg), and placebo for 21 days (four periods). Allergen challenge was performed 1 h post-dose on day 21. AHR was assessed on day 22 using methacholine.

RESULTS

Allergen challenge caused an early change (0-2 h) in minimum forced expiratory volume in 1 s (FEV(1)) of -1.091 l (95% CI: -1.344; -0.837) following placebo therapy; changes were -0.955 l (-1.209; -0.702), -0.826 l (-1.070; -0.581), and -0.614 l (-0.858; -0.370) following VI, FF, or FF/VI therapy, respectively. Treatment differences were significant for all comparisons between therapies. Mean changes in 0-2 h %FEV(1) were as follows: -28.05 (placebo), -23.10 (VI), -22.33 (FF), and -16.10 (FF/VI). Following placebo, the late change (4-10 h) in weighted mean FEV(1) was -0.466 l (-0.589; -0.343) and -0.298 l (-0.415; -0.181) after VI, and was +0.018 l with both FF/VI (-0.089; 0.124) and FF (-0.089; 0.125). Treatment differences were significant for all comparisons between therapies except FF/VI vs FF. Mean changes in 4-10 h %FEV(1) were as follows: -21.08 (placebo), -14.30 (VI), -5.02 (FF), and -5.83 (FF/VI). AHR 24 h after allergen challenge was significantly reduced with FF/VI and FF vs placebo, and FF/VI was superior to either component.

CONCLUSION

Combined treatment with FF/VI provides additive protection from the EAR relative to its components, significant protection over VI alone from the LAR, and confers sustained protection from hyper-responsiveness 24 h post-dose.

Cigarette smoking is associated with high prevalence of chronic rhinitis and low prevalence of allergic rhinitis in men

BACKGROUND

The harmful effects of tobacco smoke on human health, including respiratory health, are extensive and well documented. Previous data on the effect of smoking on rhinitis and allergic sensitization are inconsistent. We sought to investigate how smoking correlates with prevalence of allergic and chronic rhinitis among adults in Sweden.

METHODS

The study population comprised 27 879 subjects derived from three large randomly selected cross-sectional population surveys conducted in Sweden between 2006 and 2008. The same postal questionnaire on respiratory health was used in the three surveys, containing questions about obstructive respiratory diseases, rhinitis, respiratory symptoms and possible determinants of disease, including smoking habits. A random sample from one of the cohorts underwent a clinical examination including skin prick testing.

RESULTS

Smoking was associated with a high prevalence of chronic rhinitis in both men and women and a low prevalence of allergic rhinitis in men. These associations were dose dependent and remained when adjusted for a number of possible confounders in multiple logistic regression analysis. Prevalence of chronic rhinitis was lowest in nonsmokers and highest in very heavy smokers (18.5% vs 34.5%, P < 0.001). Prevalence of sensitization to common airborne allergens was lower in current smokers (25.9%, P = 0.008) and ex-smokers (28.2%, P = 0.022) than in nonsmokers (38.5%).

CONCLUSION

We found that smoking was associated with a high prevalence of chronic rhinitis in both sexes and a low prevalence of allergic rhinitis in men. The associations were dose dependent and remained when adjusting for several possible confounders.

International consensus on (ICON) pediatric asthma

Asthma is the most common chronic lower respiratory disease in childhood throughout the world. Several guidelines and/or consensus documents are available to support medical decisions on pediatric asthma. Although there is no doubt that the use of common systematic approaches for management can considerably improve outcomes, dissemination and implementation of these are still major challenges. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), recently formed by the EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus on (ICON) Pediatric Asthma. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences, thus providing a concise reference. The principles of pediatric asthma management are generally accepted. Overall, the treatment goal is disease control. To achieve this, patients and their parents should be educated to optimally manage the disease, in collaboration with healthcare professionals. Identification and avoidance of triggers is also of significant importance. Assessment and monitoring should be performed regularly to re-evaluate and fine-tune treatment. Pharmacotherapy is the cornerstone of treatment. The optimal use of medication can, in most cases, help patients control symptoms and reduce the risk for future morbidity. The management of exacerbations is a major consideration, independent of chronic treatment. There is a trend toward considering phenotype-specific treatment choices; however, this goal has not yet been achieved.

Eczema among adults: prevalence, risk factors and relation to airway diseases. Results from a large-scale population survey in Sweden

BACKGROUND

In contrast to asthma and rhinitis, few studies among adults investigating the prevalence and risk factors of eczema have been published.

OBJECTIVES

To investigate the prevalence and risk factors of eczema among adults in West Sweden. A further aim was to study the associations between asthma, rhinitis and eczema.

METHODS

A questionnaire on respiratory health was mailed in 2008 to 30,000 randomly selected subjects in West Sweden aged 16-75 years; 62% responded. The questionnaire included questions about eczema, respiratory symptoms and diseases and their possible determinants. A subgroup of 669 subjects underwent skin prick testing against common airborne allergens.

RESULTS

'Eczema ever' was reported by 40·7% and 'current eczema' by 11·5%. Both conditions were significantly more common among women. The prevalence decreased with increasing age. The coexistence of both asthma and rhinitis with eczema was common. The main risk factors were family history of allergy and asthma. The dominant environmental risk factor was occupational exposure to gas, dust or fumes. Smoking increased the risk. Eczema was associated with urbanization, while growing up on a farm was associated with a decreased risk. Added one by one to the multivariate model, asthma, allergic rhinitis and any positive skin prick test were associated with eczema.

CONCLUSIONS

Eczema among adults is a common disease with more women than men having and having had eczema. Eczema is associated with other atopic diseases and with airway symptoms. Hereditary factors and exposure to gas, dust and fumes are associated with eczema.

Efficacy and safety of 4 weeks' treatment with combined fluticasone furoate/vilanterol in a single inhaler given once daily in COPD: a placebo-controlled randomised trial

Background Fluticasone furoate/vilanterol (FF/VI) is a novel once-daily (OD) inhaled corticosteroid/long-acting β(2) agonist combination in development for chronic obstructive pulmonary disease (COPD) and asthma. Trial design A multicentre, randomised, double-blind, parallel-group, placebo-controlled study. Methods Participants were patients with moderate-to-severe COPD treated with placebo or FF/VI 400/25 μg OD for 4 weeks. Study objectives were to assess the safety and efficacy of FF/VI 400/25 μg OD administered for 4 weeks via a novel dry powder inhaler. Co-primary end points were change from baseline in weighted mean (wm) heart rate 0-4 h postdose at day 28 and the incidence of adverse events (AEs). Secondary end points included change from baseline in trough forced expiratory volume in one second (FEV(1)) (23-24 h postdose; day 29) and wm FEV(1) (0-4 h postdose; day 28). Patients were randomised to receive FF/VI 400/25 μg or placebo in a 2:1 ratio; all patients and investigators were blinded to active or placebo treatment. Results 60 patients (mean age 64 years) were randomised (FF/VI: n=40; placebo: n=20), and all contributed data to the analysis. Mean screening post-bronchodilator FEV(1) per cent predicted was comparable between groups (FF/VI: 58.5%; placebo: 60.1%). The wm heart rate 0-4 h postdose was similar between groups (difference: 0.6 beats per minute; 95% CI -3.9 to 5.1). More on-treatment AEs were reported in the FF/VI group (68%) compared with the placebo group (50%). The most common drug-related AEs in the FF/VI group were oral candidiasis (8%) and dysphonia (5%). There were no clinically relevant effects on laboratory values, including glucose and potassium, or on vital signs or ECGs/Holters. The FF/VI group had statistically greater improvements compared with placebo in trough FEV(1) (mean difference 183 ml) and 0-4 h postdose wm FEV(1) (mean difference 236 ml). Conclusion FF/VI has a good safety and tolerability profile and improves lung function compared with placebo in patients with COPD. Trial registration number clinical trials.gov-NCT00731822.

New topics in bradykinin research

Bradykinin has been implicated to contribute to allergic inflammation and the pathogenesis of allergic conditions. It binds to endothelial B(1) and B(2) receptors and exerts potent pharmacological and physiological effects, notably, decreased blood pressure, increased vascular permeability and the promotion of classical symptoms of inflammation such as vasodilation, hyperthermia, oedema and pain. Towards potential clinical benefit, bradykinin has also been shown to exert potent antithrombogenic, antiproliferative and antifibrogenic effects. The development of pharmacologically active substances, such as bradykinin receptor blockers, opens up new therapeutic options that require further research into bradykinin. This review presents current understanding surrounding the role of bradykinin in nonallergic angioedema and other conditions seen by allergists and emergency physicians, and its potential role as a therapeutic target.

Reliability of EP3OS symptom criteria and nasal endoscopy in the assessment of chronic rhinosinusitis--a GA² LEN study

BACKGROUND

The European Position Paper on Rhinosinusitis and Nasal Polyps (EP3OS) incorporates symptomatic, endoscopic, and radiologic criteria in the clinical diagnosis of chronic rhinosinusitis (CRS), while in epidemiological studies, the definition is based on symptoms only. We aimed to assess the reliability and validity of a symptom-based definition of CRS using data from the GA(2) LEN European survey.

METHODS

On two separate occasions, 1700 subjects from 11 centers provided information on symptoms of CRS, allergic rhinitis, and asthma. CRS was defined by the epidemiological EP3OS symptom criteria. The difference in prevalence of CRS between two study points, the standardized absolute repeatability, and the chance-corrected repeatability (kappa) were determined. In two centers, 342 participants underwent nasal endoscopy. The association of symptom-based CRS with endoscopy and self-reported doctor-diagnosed CRS was assessed.

RESULTS

There was a decrease in prevalence of CRS between the two study phases, and this was consistent across all centers (-3.0%, 95% CI: -5.0 to -1.0%, I(2) = 0). There was fair to moderate agreement between the two occasions (kappa = 39.6). Symptom-based CRS was significantly associated with positive endoscopy in nonallergic subjects, and with self-reported doctor-diagnosed CRS in all subjects, irrespective of the presence of allergic rhinitis.

CONCLUSION

Our findings suggest that a symptom-based definition of CRS, according to the epidemiological part of the EP3OS criteria, has a moderate reliability over time, is stable between study centers, is not influenced by the presence of allergic rhinitis, and is suitable for the assessment of geographic variation in prevalence of CRS.

Multi-symptom asthma as an indication of disease severity in epidemiology

Epidemiological questionnaires have failed to identify individuals with severe asthma. The extent of symptoms of asthma can, however, be easily established in epidemiology, by identification of multiple symptoms. We hypothesise that reporting of multiple symptoms of asthma reflects uncontrolled disease and is a sign of more severe asthma. The aims of the current study were, therefore, to determine the prevalence and determinants of multi-symptom asthma. A postal questionnaire was sent to 30,000 randomly selected individuals aged 16-75 yrs. A subgroup underwent clinical examinations. Multi-symptom asthma was defined as reported physician-diagnosed asthma, use of asthma medication, recurrent wheeze, attacks of shortness of breath and at least one additional respiratory symptom. The prevalence of multi-symptom asthma was 2.0%, and it was more common among females (2.4 versus 1.5%; p<0.001) and those with a body mass index >30 kg · m(-2). Multi-symptom asthmatics had lower forced expiratory volume in 1 s, higher exhaled nitric oxide fraction and more pronounced hyperresponsiveness. Family history of both asthma and allergy (OR 7.3), and occupational exposure to gas dust or fumes (OR 2.0) were also significant risk factors. Multi-symptom asthmatics comprise 2% of the general population; multi-symptom asthma is related to signs of more severe disease and could be used as an epidemiological marker of disease severity.

Growing up on a farm leads to lifelong protection against allergic rhinitis

BACKGROUND

Various studies have reported a low prevalence of allergic rhinitis in farmers and farmers' children. We sought to investigate whether the protective effect of childhood farm environment is conserved throughout adulthood and how it corresponds to different degrees of urbanization.

METHODS

A questionnaire on respiratory health was mailed in 2008 to 30,000 randomly selected subjects aged 16-75 in West Sweden, 29,218 could be traced and 18,087 (62%) responded. The questionnaire included questions on allergic rhinitis, asthma, respiratory symptoms and possible determinants.

RESULTS

When stratified into age groups of 15 years, subjects that lived on a farm during their first 5 years of life had a lower prevalence of allergic rhinitis in all groups, even among the oldest (61-75 years). The negative correlation between childhood farm living and prevalence of allergic rhinitis was similar in 46-75 years of age (OR 0.82; 95% CI 0.70-0.95) as in 16-45 years of age (OR 0.78; 0.64-0.95). There was a significant trend of increasing prevalence of allergic rhinitis with increasing degree of urbanization independent of the effect of childhood farm living.

CONCLUSIONS

We found a lifelong protective effect of childhood farm living on the prevalence of allergic rhinitis. In addition, we found an increasing prevalence of allergic rhinitis with increasing degree of urbanization both in those raised on a farm and those not, thus emphasizing the influence of both childhood and adult exposure for the development of allergic disease.

Development and implementation of guidelines in allergic rhinitis – an ARIA-GA2LEN paper

The links between asthma and rhinitis are well characterized. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines stress the importance of these links and provide guidance for their prevention and treatment. Despite effective treatments being available, too few patients receive appropriate medical care for both diseases. Most patients with rhinitis and asthma consult primary care physicians and therefore these physicians are encouraged to understand and use ARIA guidelines. Patients should also be informed about these guidelines to raise their awareness of optimal care and increase control of the two related diseases. To apply these guidelines, clinicians and patients need to understand how and why the recommendations were made. The goal of the ARIA guidelines is to provide recommendations about the best management options for most patients in most situations. These recommendations should be based on the best available evidence. Making recommendations requires the assessment of the quality of available evidence, deciding on the balance between benefits and downsides, consideration of patients’ values and preferences, and, if applicable, resource implications. Guidelines must be updated as new management options become available or important new evidence emerges. Transparent reporting of guidelines facilitates understanding and acceptance, but implementation strategies need to be improved.

IL-5 expression and release from human CD34 cells in vitro; ex vivo evidence from cases of asthma and Churg-Strauss syndrome

BACKGROUND

Eosinophils develop from hematopoietic CD34(+) progenitor cells in the bone marrow (BM) under the influence of Interleukin-5 (IL-5). The primary source of IL-5 is T-lymphocytes, although other sources may exist. The aims of this study were to determine whether CD34(+) cells from human peripheral blood (PB) and BM have the capacity to produce IL-5 when stimulated in vitro, and secondly, whether an elevated number of IL-5-producing CD34(+) cells can be found in situ in ongoing eosinophilic disease.

METHODS

CD34(+) cells from PB and BM were stimulated in vitro, and IL-5 production and release was assessed by ELISA, ELISPOT, flow cytometry and immunocytochemistry. Blood and BM from a patient with Churg-Strauss syndrome were analyzed by flow cytometry for CD34(+)/IL-5(+) cells, and immunohistochemical staining of CD34(+)/IL-5(+) cells in bronchial biopsies from an asthmatic patient was performed.

RESULTS

Both PB and BM CD34(+) cells can produce and release IL-5 when stimulated in vitro. In the Churg-Strauss patient, IL-5-producing CD34(+) cells were found in PB and BM. Oral glucocorticoid treatment markedly decreased the number of IL-5-positive CD34 cells in the BM. CD34(+)/IL-5(+) cells were present in a patient with asthma.

CONCLUSION

CD34(+) cells in blood and BM are capable of producing IL-5 both in vitro and in vivo in humans, arguing that these cells may have the capacity to contribute to eosinophilic inflammation. Consequently, targeting CD34(+) progenitor cells that produce and release IL-5 may be effective in reducing the mobilization of eosinophil lineage-committed cells in eosinophilic-driven diseases.

Osteopontin expression and relation to disease severity in human asthma

Recent studies have associated osteopontin (OPN) with allergic inflammation; however, its role in human asthma remains unclear. The aim of this study was to measure OPN levels in the serum, bronchoalveolar lavage fluid (BALF) and bronchial tissue of healthy controls and asthmatics, identify cellular sources of OPN and examine possible correlations between OPN expression, disease severity and airway remodelling. Serum samples were obtained from 35 mild-to-moderate asthmatics, 19 severe asthmatics and 17 healthy controls in the steady state and in cases of exacerbation. Of these subjects, 29 asthmatics and nine controls underwent bronchoscopy with endobronchial biopsy and BALF collection. OPN expression was determined by ELISA and immunohistochemistry/immunofluorescence. Reticular basement membrane thickness and goblet cell hyperplasia were also determined. Serum and BALF OPN levels were significantly increased in all asthmatics in the steady state, whereas serum levels decreased during exacerbations. OPN was upregulated in the bronchial tissue of all patients, and expressed by epithelial, airway and vascular smooth muscle cells, myofibroblasts, T-lymphocytes and mast cells. OPN expression correlated with reticular basement membrane thickness and was more prominent in subepithelial inflammatory cells in severe compared to mild-to-moderate asthma. OPN expression is upregulated in human asthma and associated with remodelling changes, and its subepithelial expression correlates with disease severity.

New production of eosinophils and the corresponding TH1/TH2 balance in the lungs after allergen exposure in BALB/c and C57BL/6 mice

Allergic asthma is associated with eosinophilic inflammation in the airways. Animal models commonly used to elucidate allergic inflammation mechanisms include BALB/c and C57BL/6 mice. Our aim was to evaluate lung eosinophilia and the corresponding Th1/Th2 balance in the two strains after allergen exposure. BALB/c and C57BL/6 mice were subjected to ovalbumin-induced allergic airway inflammation using BrdU to label newly produced cells. The numbers of new eosinophils were evaluated by differential cell count and immunocytochemistry (MBP+BrdU+). Proliferation rate of lung eosinophils was measured by analysis of CD45+CCR3+BrdU+ cells by FACS. Distribution of newly produced eosinophils in the lung and the Th1/Th2 (CD4+T-bet+/CD4+GATA-3+) balance was evaluated by immunohistochemistry. Allergen challenge with ovalbumin induced comparable eosinophilia in bone marrow (BM), blood and lung tissue in both strains of mice compared to phosphate-buffered saline controls, which was confirmed by immunocytochemistry. There was a small increase in the number of lung MBP+BrdU(-) eosinophils in C57BL/6 mice compared to BALB/c mice, which suggests a basal increase in this strain following sensitization. While there was no difference in eosinophilic proliferation in the lung, the distribution of the newly produced eosinophils differs between the two strains. BALB/c mice showed staining primarily around vessels and airways, whereas C57BL/6 mice showed a more even distribution in the lung tissue. No difference in the Th1/Th2 balance was observed between two strains. This study shows that there is a difference in the distribution of eosinophils in the lung between the C57BL/6 and BALB/c mice, but no difference in eosinophil production or Th1/Th2 balance.

Personality, adherence, asthma control and health-related quality of life in young adult asthmatics

BACKGROUND

Striving for improved adherence and asthma control is of vital concern in today's asthma management. Several influential factors have been identified, but the importance of personality traits has been insufficiently explored. The aim was first to determine whether personality traits in young adult asthmatics are related to asthma control and health-related quality of life (HRQL), and second to examine the influences of personality traits on adherence to regular asthma medication treatment.

METHODS

Young adult asthmatics, 22 years of age (n=268) completed questionnaires. Statistical analyses were performed.

RESULTS

The personality traits Negative Affectivity and Impulsivity correlated negatively with asthma control, whereas in women Hedonic Capacity correlated positively with asthma control. Negative Affectivity, Impulsivity, Hedonic Capacity, Alexithymia and asthma control predicted the mental dimension of HRQL. Asthma control and physical activity predicted the physical dimension of HRQL. Among respondents with regular asthma medication (n=109), Impulsivity correlated negatively with adherence. In men, Antagonism and Alexithymia were associated with low adherence. Additionally, Alexithymia, Hedonic Capacity and Negative Affectivity showed non-linear relationships with adherence, meaning that initially increased scores on these personality traits scales were associated with increased adherence but higher scores did not increase adherence. Respondents who were prescribed a single inhaler combining ICS and LABA reported higher adherence than those with monotherapies.

CONCLUSION

These data suggest that personality can influence how asthma patients adhere to asthma medication treatment, and report their control and HRQL. Tools determining personality traits may be useful in the future in individualizing management of asthma patients.

Rhinovirus infection and house dust mite exposure synergize in inducing bronchial epithelial cell interleukin-8 release

BACKGROUND

Human rhinoviruses (HRVs) and house dust mites (HDMs) are among the most common environmental factors able to induce airway inflammation in asthma. Although epidemiological studies suggest that they also synergize in inducing asthma exacerbations, there is no experimental evidence to support this, nor any information on the possible mechanisms involved.

OBJECTIVE

To investigate their interaction on the induction of airway epithelial inflammatory responses in vitro.

METHODS

BEAS-2B cells were exposed to activated HDM Dermatophagoides pteronyssinus major allergen I (Der p I), HRVs (HRV1b or HRV16) or both in different sequences. IL-8/CXCL8 release, intercellular adhesion molecule (ICAM)-1 surface expression and nuclear factor kappaB (NF-kappaB) translocation were evaluated. Complementary, primary human bronchial epithelial cells (HBECs) exposed to both Der p I and RVs and IL-8, IL-6, IFN-gamma-induced protein (IP)-10/CXCL10, IFN-lambda1/IL-29, regulated upon activation normal T lymphocyte expressed and secreted (RANTES)/CCL5 release were measured.

RESULTS

RV and Der p I up-regulated IL-8 release, ICAM-1 expression and NF-kappaB translocation in BEAS-2B cells. Simultaneous exposure to both factors, as well as when cells were initially exposed to HRV and then to Der p I, resulted in further induction of IL-8 in a synergistic manner. Synergism was not observed when cells were initially exposed to Der p I and then to HRV. This was the pattern in ICAM-1 induction although the phenomenon was not synergistic. Concurrent exposure induced an early synergistic NF-kappaB translocation induction, differentiating with time, partly explaining the above observation. In HBECs, both HRV and Der p I induced IL-8, IL-6, IL-29 and IP-10, while RANTES was induced only by HRV. Synergistic induction was observed only in IL-8.

CONCLUSION

HRV and enzymatically active Der p I can act synergistically in the induction of bronchial epithelial IL-8 release, when HRV infection precedes or is concurrent with Der p I exposure. Such a synergy may represent an important mechanism in virus-induced asthma exacerbations.

Exercise-induced hypersensitivity syndromes in recreational and competitive athletes: a PRACTALL consensus report (what the general practitioner should know about sports and allergy)

Exercise-induced (EI) hypersensitivity disorders are significant problems for both recreational and competitive athletes. These include EI-asthma, EI-bronchoconstriction, EI-rhinitis, EI-anaphylaxis and EI-urticaria. A group of experts from the European Academy of Allergology and Clinical Immunology and the American Academy of Allergy Asthma and Immunology met to discuss the pathogenesis of these disorders and how to diagnose and treat them, and then to develop a consensus report. Key words (exercise with asthma, bronchoconstriction, rhinitis, urticaria or anaphylaxis) were used to search Medline, the Cochrane database and related websites through February 2008 to obtain pertinent information which, along with personal reference databases and institutional experience with these disorders, were used to develop this report. The goal is to provide physicians with guidance in the diagnosis, understanding and management of EI-hypersensitivity disorders to enable their patients to safely return to exercise-related activities.

Prolonged eosinophil production after allergen exposure in IFN-gammaR KO mice is IL-5 dependent

Asthma is a T helper 2 (Th2)-driven inflammatory process characterized by eosinophilia. Prolonged airway eosinophilia is commonly observed in asthma exacerbations. Our aim was to evaluate whether eosinophilia in prolonged allergic inflammation is associated with a continuous supply of new eosinophils to the airways, and how this is regulated. Ovalbumin (OVA)-sensitized interferon-gamma receptor knockout mice (IFN-gammaR KO), known to maintain a long-lasting eosinophilia after allergen exposure, were compared to wild type (wt) controls. Animals were exposed to OVA or phosphate-buffered saline on three consecutive days, and bone marrow (BM), blood and bronchoalveolar lavage (BAL) samples were collected 24 h, 7 and 21 days later. Newly produced cells were labelled using bromodeoxyuridine (BrdU). Serum IL-5 was measured and its role was investigated by administration of a neutralizing anti-IL-5 antibody. In-vitro eosinophilopoiesis was examined in both groups by a colony-forming assay. Allergen challenge increased eosinophils in BM, blood and BAL, in both IFN-gammaR KO and wt mice, both 24 h and 7 days after the last allergen exposure. At 21 days after the last exposure, only IFN-gammaR KO mice maintained significantly increased eosinophil numbers. Approximately 50% of BAL granulocytes in IFN-gammaR KO were produced during the last 6 days. Interleukin (IL)-5 concentration was increased in IFN-gammaR KO mice, and anti-IL-5 reduced eosinophil numbers in all compartments. Increased numbers of eosinophil colonies were observed in IFN-gammaR KO mice after allergen exposure versus controls. In this model of a Th2-driven prolonged allergic eosinophilia, new eosinophils contribute to the extended inflammation in the airways by enhanced BM eosinophilopoiesis in an IL-5-dependent manner.

Exosomes - nanovesicles with possible roles in allergic inflammation

Exosomes are nano-sized membrane vesicles which are released extracellularly after fusion of multivesicular endosomes with the cell membrane. Despite their characteristic composition of proteins compared to the cell membrane, no exosome-specific molecule has so far been characterized. Exosomes are found in bronchoalveolar lavage (BAL), urine, serum and breast milk, and are released from several cells implicated in allergy including mast cells, dendritic cells (DC), T cells and epithelial cells. Antigen-loaded exosomes have been shown to be highly immunogenic and we propose that exosomes could be a modulating factor in allergic responses. Allergen-presenting exosomes could transport allergen and stimulate allergen-specific T cells, and possibly also biasing T cell responses depending on the molecules present on the exosome surface. Furthermore, exosomes from mast cells, highly active in allergic reactions, have been found to induce DC maturation and also to be able to transport functional RNA to recipient cells, suggesting a new pathway for cell communication. Reversely, tolerizing exosomes e.g. tolerosomes, from gut or breast milk, could block an allergic response or prevent allergy development. A better understanding of the role of exosomes in allergies could make us understand how allergy can be prevented or lead to the development of more efficient treatments.

Regulation of allergen-induced bone marrow eosinophilopoiesis: role of CD4+ and CD8+ T cells

BACKGROUND

The mechanisms of the distant stimulation of the bone marrow (BM) after airway allergen exposure remain largely obscure. T cells have been implicated in allergic airway inflammation but their role in allergen-induced BM eosinophilopoiesis is poorly understood. The aim of this study was to determine the role of CD4(+) and CD8(+) T cells in allergen-induced BM eosinophilopoiesis.

METHODS

Ovalbumin (OVA)-sensitized wild type (WT), CD4 knockout (CD4-/-) and CD8 knockout (CD8-/-) mice were exposed intranasally to OVA or saline. Bromo-deoxyuridine (BrdU) was used to label newly produced cells. Bone marrow, blood and bronchoalveolar lavage (BAL) were sampled 24 h after the final exposure. Immunostaining for newly produced eosinophils (i.e. BrdU(+)/MBP(+)) and BM eosinophil progenitor [CD34(+)/CD45(+)/interleukin-5 (IL-5)Ralpha(+)] cells was performed.

RESULTS

The number of newly produced BM eosinophils (BrdU(+)/MBP(+) cells) was significantly reduced in allergen exposed CD4-/- or CD8-/- mice compared with allergen exposed WT mice, which was followed by a subsequent decrease in newly produced blood and airway eosinophils. Furthermore, BM eosinophil progenitors were significantly reduced in allergen exposed CD4-/- and CD8-/- mice compared with WT mice. Finally, serum IL-5 and Bronchoalveolar lavage fluid eotaxin-2 levels were abolished in allergen exposed CD4-/- mice to levels seen in saline exposed WT mice.

CONCLUSIONS

These data suggests that both CD4(+) and CD8(+) T cells have a regulatory role in allergen-induced BM eosinophilopoiesis, whereas CD4(+) T cells are obligatory for allergen-induced airway eosinophilia. The subsequent traffic of eosinophils to the airways is likely to be at least partly regulated by a CD4(+) T-cell-dependent local airway eotaxin-2 production.

Comparison of the efficacy of salmeterol/fluticasone propionate combination in Japanese and Caucasian asthmatics

INTRODUCTION

The effect of ethnicity on the efficacy of salmeterol (S)+fluticasone propionate (FP) has not been examined in Japanese and Caucasian asthmatics. In this study, the efficacy of combination treatment with S and FP from a single inhaler (SFC) was compared with concurrent treatment with S and FP administration from separate inhalers (S+FP) in Japanese and Caucasian asthmatics.

METHODS

This was a randomised, double-blind, crossover study in male and female Japanese (n=18) and Caucasian (n=17) asthmatics (50-100% predicted FEV(1); >35% reversibility in sGaw). Subjects received SFC (S 50 mcg/FP 250 mcg b.i.d.) and S+FP (S 50 mcg b.i.d.+FP 250 mcg b.i.d.) for 14 days. sGaw and FEV(1) were determined 0-12h after the first and last doses.

RESULTS

Treatment with both SFC and S+FP produced marked bronchodilation, which was maintained 0-12h after the first dose. Baseline sGaw and FEV(1) increased up to 51% and 180 mL, respectively, in Japanese subjects over 2 weeks of treatment, with similar improvements in Caucasian subjects. On Day 14 the 0-12h S+FP:SFC treatment ratios (90% CI) for sGaw AUC and peak were 1.05 (0.98, 1.12) and 1.05 (0.97, 1.14), respectively, in Japanese subjects, and 0.99 (0.92, 1.07) and 0.98 (0.89, 1.07), respectively, in Caucasian subjects, with no difference between the two ethnic groups.

CONCLUSIONS

The finding of a similar significant bronchodilator response in Japanese and Caucasian asthmatics following concurrent and combination treatment with salmeterol and FP suggests that the therapeutic response to these agents is comparable and independent of ethnicity in Japanese and Caucasian asthma patients.

Effects of pollen and nasal glucocorticoid on FOXP3+, GATA-3+ and T-bet+ cells in allergic rhinitis

BACKGROUND

T-regulatory cells (Treg) affect the balance of T(H)2 and T(H)1 cells. Treg, T(H)2 and T(H)1 cells are regulated by the FOXP3, GATA-3 and T-bet transcription factors respectively. Our aim was to determine the number of FOXP3(+), GATA-3(+) and T-bet(+) cells in nasal mucosa in symptom-free allergic rhinitis (AR) patients vs healthy controls, as well as the effects of natural pollen exposure and concomitant nasal glucocorticoid treatment on these cells.

METHODS

Nasal biopsies were taken from healthy controls and patients with grass-pollen AR preseason. The AR patients were randomized to receive treatment with either fluticasone propionate (FP) or a placebo, and additional biopsies were taken during the pollen season. FOXP3(+), GATA-3(+) and T-bet(+) cells in nasal mucosa were quantified by immunohistochemistry.

RESULTS

The number of FOXP3(+) and GATA-3(+) cells, but not T-bet(+) cells, was significantly higher in AR patients vs controls preseason. The number of FOXP3(+) cells remained unchanged in the former group after the pollen season but decreased significantly in the nasal mucosa as a result of FP treatment. The pollen season substantially increased the number of GATA-3(+) cells, which was inhibited by FP. The number of T-bet(+) cells was not affected by pollen or FP.

CONCLUSION

These data suggest that nasal glucocorticoids attenuate the allergic inflammation partly by reducing the number of T(H)2 cells, but not by means of local upregulation of Treg cells. The local relationship between T(H)1 and T(H)2 cells as well as between Treg and T(H)2 is maintained by nasal glucocorticoid treatment.

Increased number of CD34+ cells in nasal mucosa of allergic rhinitis patients: inhibition by a local corticosteroid

BACKGROUND

Eosinophils develop from CD34+ haematopoietic progenitor cells. Allergen exposure in susceptible individuals is known to induce a local eosinophilic inflammation, but the effect on progenitor cells is much less understood.

OBJECTIVE

We aimed to evaluate how allergen exposure affects the number of tissue CD34+ cells and CD34+ eosinophils in allergic rhinitis (AR) patients and whether any such effect is influenced by local corticosteroid treatment. Also, we evaluated changes in the number of CXC receptor 4-positive cells (CXCR4+), since the CXCR4 ligand (stromal cell-derived factor-1 (SDF-1)) is a potent chemoattractant for haematopoietic progenitors.

METHODS

In a double-blind, randomized study, pollen-sensitized AR patients were treated with a nasal corticosteroid fluticasone propionate (FP, 200 microg/day) or placebo throughout the pollen season. Nasal biopsies were taken before and during the season. CD34 and CXCR4 were stained using immunohistochemistry.

RESULTS

The pollen season significantly increased the number of CD34+ cells, CD34+/CXCR4+ cells and CD34+ eosinophils in placebo-treated patients, but not in FP-treated patients. The mean pollen season-induced increase in CD34+ cells, CD34+/CXCR4+ cells and CD34+ eosinophils in FP-treated patients was lower compared with placebo-treated patients.

CONCLUSION

A pollen season increases the number of CD34+ cells in nasal tissue accompanied by an increase in the number of CD34+/CXCR4+ haematopoietic progenitors and also the number of CD34+ eosinophils in subjects with AR. Treatment with a local corticosteroid provides protection against this pollen-induced increase in tissue CD34+ cells and CD34+ eosinophils possibly via inhibition of allergen-induced CXCR4-mediated recruitment of CD34+ haematopoietic progenitors into airways and their further differentiation into eosinophils within the tissue.

Differential effects of fluticasone and montelukast on allergen-induced asthma

Early asthmatic responses (EAR) and late asthmatic responses (LAR) to allergen are induced by the local release of a series of bronchoconstrictor mediators, including leukotrienes and histamine. Both anti-leukotrienes and other anti-asthma drugs, such as inhaled glucocorticoids, have been shown to reduce both EAR and LAR. The aim of the present study was to directly compare the effects of regular treatment with an oral anti-leukotriene, montelukast (Mont; 10 mg once daily, for 8 days), and an inhaled glucocorticoid [fluticasone propionate (FP) 250 microg twice daily for 8 days] on the EAR and LAR to an inhaled allergen challenge. Patients with a documented EAR and LAR at a screening visit were randomized to these treatments, or placebo, in a double-blind, double-dummy, crossover fashion. Allergen challenge at a dose causing both an EAR and LAR was given on the eighth day of treatment. The maximum fall in FEV1 during the EAR was 17.8% during placebo treatment, 8.3% during Mont and 16.3% during FP (P <0.05 for Mont vs placebo). The maximum fall during the EAR was 13.8% during placebo treatment, 11.8% during Mont and 2% during FP treatment (P <0.05 for FP vs placebo and FP vs Mont). PC20 methacholine was significantly higher 24 h after allergen challenge during FP-treatment compared with Mont (P <0.05). Both montelukast and fluticasone reduced the relative amount of sputum eosinophils after allergen compared with placebo treatment. This study shows that anti-leukotrienes are effective to attenuate the EAR, whereas inhaled glucocorticoids are more effective than anti-leukotrienes in attenuating the EARs and improves bronchial hyperresponsiveness to a greater extent. In conclusion, inhaled glucocorticoids have overall greater efficacy than oral anti-leukotrienes to attenuate allergen-induced airway responses in mild asthmatic patients.

Allergen stimulates bone marrow CD34(+) cells to release IL-5 in vitro; a mechanism involved in eosinophilic inflammation?

The specific mechanisms that alter bone marrow (BM) eosinophilopoiesis in allergen-induced inflammation are poorly understood. The aims of this study were to evaluate (a) whether the number of BM CD34(+) cells is altered due to allergen sensitization and exposure in vivo and (b) whether BM CD34(+) cells produce and release interleukin (IL)-5, IL-3 and granulocyte macrophage-colony stimulating factor (GM-CSF) after stimulation in vitro. A mouse model of ovalbumin (OVA)-induced airway inflammation was used. Bone marrow CD34(+) cells were cultured in vitro and the cytokine release was measured by enzyme-linked immunosorbent assay. The IL-5-production from CD34(+) cells was confirmed by immunocytochemistry. Airway allergen exposure increased the number of BM CD34(+) cells (P = 0.01). Bone marrow CD34(+) cells produced IL-5 when stimulated with the allergen OVA in vitro, but not IL-3 or GM-CSF. Nonspecific stimulus with calcium ionophore and phorbol-myristate-acetate of BM CD34(+) cells caused release of IL-5, IL-3 and GM-CSF. The induced release of IL-5 was increased in alum-injected vs naive mice (P = 0.02), but was not affected by allergen sensitization and exposure. The release of IL-3 and GM-CSF was increased after allergen sensitization and exposure (P < 0.02). In conclusion, allergen can stimulate BM CD34(+) cells to produce IL-5 protein. It is likely that the CD34(+) cells have autocrine functions and thereby regulate the early stages of BM eosinophilopoiesis induced by airway allergen exposure. Alum, a commonly used adjuvant, enhances the release of IL-5 and may thereby enhance eosinophilopoiesis.

β‐Adrenoceptor stimulation and neutrophil accumulation in mouse airways

This study characterised the effect of beta-adrenoceptor stimulation on endotoxin-induced accumulation of neutrophilic granulocytes in mouse airways, where the cytokines interleukin (IL)-6 and macrophage inflammatory protein (MIP)-2 are involed as mediators. The beta2-adrenoceptor agonist salbutamol (0.025-250 fMol) was administered intranasally in mice 24 h prior to administration of endotoxin (10 microg) intranasally. Bronchoalveolar lavage (BAL) fluid and venous blood, respectively, was harvested (6 or 24 h) after administration of endotoxin. Salbutamol substantially decreased the number of neutrophils in BAL fluid from endotoxin-exposed (6 and 24 h) mice and this effect was dose dependent (24 h). Pretreatment with the beta-adrenoceptor antagonist propranolol attenuated the inhibitory effect of salbutamol on BAL neutrophils (6 and 24 h), an attenuation that was not due to any unspecific effect of propranolol. Salbutamol also substantially decreased IL-6, but not MIP-2 in BAL fluid (6 h). In contrast to BAL fluid, salbutamol caused a moderate increase in blood neutrophils (24 h). In conclusion, as indicated in mouse airways in vivo, beta-adrenoceptor stimulation prior to endotoxin exposure inhibits the induced accumulation of neutrophils at a time point much later than that anticipated from its bronchodilatory effect. Even though the detailed molecular mechanisms behind this sustained "anti-inflammatory" effect remain unknown, it seems likely that this effect is in part due to a decrease in the local concentration of interleukin-6.

Efficacy and safety of a recombinant anti-immunoglobulin E antibody (omalizumab) in severe allergic asthma

BACKGROUND

Patients with severe asthma are often inadequately controlled on existing anti-asthma therapy, constituting an unmet clinical need.

OBJECTIVE

This randomized, double-blind, placebo-controlled trial evaluated the ability of omalizumab, a humanized monoclonal anti-IgE antibody, to improve disease control sufficiently to enable inhaled corticosteroid reduction in patients with severe allergic asthma.

METHODS

After a run-in period when an optimized fluticasone dose (> or =1000 microg/day) was received for 4 weeks, patients were randomized to receive subcutaneous omalizumab [minimum 0.016 mg/kg/IgE (IU/mL) per 4 weeks; n=126] or matching placebo (n=120) at intervals of 2 or 4 weeks. The study comprised a 16-week add-on phase of treatment followed by a 16-week fluticasone-reduction phase. Short-/long-acting beta(2)-agonists were allowed as needed.

RESULTS

Median reductions in fluticasone dose were significantly greater with omalizumab than placebo: 60% vs. 50% (P=0.003). Some 73.8% and 50.8% of patients, respectively, achieved a > or =50% dose reduction (P=0.001). Fluticasone dose reduction to < or =500 microg/day occurred in 60.3% of omalizumab recipients vs. 45.8% of placebo-treated patients (P=0.026). Through both phases, omalizumab reduced rescue medication requirements, improved asthma symptoms and asthma-related quality of life compared to placebo.

CONCLUSION

Omalizumab treatment improves asthma control in severely allergic asthmatics, reducing inhaled corticosteroid requirements without worsening of symptom control or increase in rescue medication use.

Relaxation kinetics of formoterol and salmeterol in the guinea pig trachea in vitro

The mechanisms producing long duration of action for formoterol and salmeterol are not fully understood. The aim of the current study was to examine how the concentration of long and short acting beta 2-adrenoceptor agonists affects their relaxation kinetics in airway smooth muscle. Onset (time to peak relaxation) and offset of action (reassertion of reversible relaxation followed repeated beta-adrenoceptor blockade and washout) were measured in the guinea pig trachea precontracted postjunctionally by carbachol 0.3 microM in vitro. At 10-1,000% (C10-C1,000) of the maximally effective concentration (C100: 150 nM formoterol, 10 microM salbutamol, 30 microM salmeterol), salbutamol had a shorter time to peak relaxation than did salmeterol. Formoterol and salmeterol had a similar time to peak relaxation at C10, but, in contrast to salmeterol, formoterol's time to peak relaxation became markedly shorter and similar to that of salbutamol as the concentration was increased up to C1,000. Significant reversible reasserted relaxation was demonstrated for salmeterol alone at C10. At C30-C1,000, however, salmeterol produced irreversible relaxation only, in spite of repeated beta-adrenoceptor blockade by sotalol 10 microM followed by washout. In contrast, formoterol produced an increasing reversible reasserted relaxation at C30-C1,000. Salbutamol produced significant, reversible reasserted relaxation at C1,000 only. In conclusion, the concentration determines the onset and offset of action for formoterol and to a lesser extent for salbutamol, but not for salmeterol. To cause sustained action, a submaximally effective concentration is sufficient for salmeterol, whereas formoterol requires a maximally effective concentration. The rank order of concentration dependence for the relaxation kinetics is not paralleled by the rank order of lipophilicity for formoterol, salbutamol, and salmeterol. Therefore, factors other than lipophilicity may also play a role in determining the relationship between concentration and relaxation kinetics for the investigated beta 2-agonists.