Haemopoietic mechanisms in murine allergic upper and lower airway inflammation

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

Upper and lower airway remodelling mechanisms in asthma,allergic rhinitis and chronic rhinosinusitis: The one airway concept revisited

Allergic rhinitis (AR), chronic rhinosinusitis (CRS) and asthma often co‐exist. The one airway model proposes that disease mechanisms occurring in the upper airway may mirror lower airway events. Airway remodelling is the term used to describe tissue structural changes that occur in a disease setting and reflect the dynamic process of tissue restructuring during wound repair. Remodelling has been long identified in the lower airways in asthma and is characterized by epithelial shedding, goblet cell hyperplasia, basement membrane thickening, subepithelial fibrosis, airway smooth muscle hyperplasia and increased angiogenesis. The concept of upper airway remodelling has only recently been introduced, and data so far are limited and often conflicting, an indication that more detailed studies are needed. Whilst remodelling changes in AR are limited, CRS phenotypes demonstrate epithelial hyperplasia, increased matrix deposition and degradation along with accumulation of plasma proteins. Despite extensive research over the past years, the precise cellular and molecular mechanisms involved in airway remodelling remain incompletely defined. This review describes our current rather limited understanding of airway remodelling processes in AR, CRS and asthma and presents mechanisms both shared and distinct between the upper and lower airways. Delineation of shared and disease‐specific pathogenic mechanisms of remodelling between the sinonasal system and the lung may guide the rational design of more effective therapeutic strategies targeting upper and lower airways concomitantly and improving the health of individuals with inflammatory airway diseases.     

Immunotherapy in allergic rhinitis and lower airway outcomes

Allergic rhinitis and asthma constitute two clinical expressions of a single‐condition, respiratory allergy. Allergen immunotherapy (AIT) is a form of treatment specifically aimed at modifying the response to sensitizing allergens. The inherent potential benefit of AIT is the simultaneous treatment of all clinical expressions of respiratory allergy. Current data support the effectiveness of subcutaneous and sublingual immunotherapy in rhinitis. Studies also provide proof for a beneficial effect in allergic asthma. Even more, substantial evidence points to the preventive effect on the progression from rhinitis to asthma. Despite the current knowledge on the basic mechanisms underlying the immunological effect of AIT is vast, the specific mechanisms for the preventive effect of primary sensitization or new sensitizations are poorly understood. This review aimed to provide a critical overview of the current knowledge on the effectiveness of AIT and its potential role in secondary prevention of respiratory allergy progression.     

Mucosal and systemic inflammatory changes in allergic rhinitis and asthma: a comparison between upper and lower airways

BACKGROUND: Local airway inflammation and airway remodelling are considered important in the clinical expression of allergic asthma. OBJECTIVE: The aim of this study was to compare airway inflammation and remodelling in nasal and bronchial mucosa of subjects with allergic rhinitis with or without asthma. METHODS: Four experimental groups were formed: allergic asthma and rhinitis (n = 19); allergic rhinitis, no asthma (n = 18); atopic subjects, no asthma, no rhinitis (n = 8) and non-allergic healthy control subjects (n = 16). Blood samples, nasal and bronchial biopsy specimens were collected during stable disease. Immunohistochemistry was performed for eosinophils (MBP), mast cells (CD117) and vascular endothelium (CD31). Epithelial loss, reticular basement membrane (RBM) thickness and subepithelial vascularity was assessed with a computer-assisted image analysis system. RESULTS: In nasal and bronchial mucosa, numbers of eosinophils were significantly higher in rhinitis patients with and without asthma than in asymptomatic atopics (P < 0.05) and controls (P < or = 0.01). In bronchial mucosa, the RBM was significantly thickened in rhinitis patients with and without asthma compared to asymptomatic atopics (P < 0.05) and controls (P < 0.01), while in nasal mucosa no differences were seen. Patients with asthma and rhinitis had increased numbers of blood eosinophils (P = 0.05) and skin test reactivity (P = 0.01) compared to patients with rhinitis only. No significant differences could be found between the investigated groups with respect to serum IL-5 and eotaxin levels, the number of mucosal mast cells and the degree of epithelial loss and subepithelial vascularity. Epithelial desquamation was significantly increased in the bronchial mucosa compared to nasal mucosa, not only in asthmatics (P < 0.001), but also in atopics without asthma and rhinitis (P = 0.02). CONCLUSIONS: This study shows that allergic inflammation, increased basement membrane thickness and epithelial desquamation are present in the lower airways of atopic subjects, even before the onset of clinical symptoms. Despite the presence of inflammatory cells, no structural changes could be assessed in nasal mucosa of allergic patients.     

Serum eosinophil granule proteins predict asthma risk in allergic rhinitis

Background: Allergic rhinitis is a common disease, in which some patients will deteriorate or develop asthma. It is important to characterize these patients, thereby offering the possibility for prevention. This study evaluated eosinophil parameters as potential indicators of deteriorating allergic airway disease. Methods: The subjects of the study included all patients who suffered seasonal allergic rhinitis and had participated in a study 6 years earlier, in which blood eosinophils, serum eosinophil cationic protein (ECP) serum eosinophil peroxidase (EPO), nasal lavage ECP and nasal lavage EPO levels were measured. Patients in the present study were interviewed on occurrence of rhinitis symptoms during the last season, rhinitis outside season, asthma‐like symptoms and asthma diagnosis, and were skin‐prick tested for common aeroallergens. Eosinophil parameters from the study 6 years earlier were then tested for the ability to predict occurrence of new allergies, worsening of rhinitis and occurrence of asthma. Results: Forty‐four patients participated in the study. In four patients seasonal rhinitis symptoms had deteriorated, 10 had experienced perennial rhinitis symptoms, 14 reported asthma‐like symptoms and seven had been diagnosed with asthma. Thirteen had developed additional sensitization. Patients developing asthma‐like symptoms compared with patients with no such symptoms had significantly higher serum ECP (16.7 μg/l vs 8.2 μg/l; P ≤ 0.01) and serum EPO (17.9 μg/l vs 8.8 μg/l; P ≤ 0.05). Results were similar, considering patients diagnosed with asthma. Blood eosinophils and nasal lavage parameters were not related to development of asthma and asthma‐like symptoms. No eosinophil parameter was related to deterioration of rhinitis or additional sensitization. Conclusion: Serum ECP and EPO in patients with seasonal rhinitis demonstrated a high predictive ability for later development of asthma.     

Common characteristics of upper and lower airways in rhinitis and asthma: ARIA update, in collaboration with GA2LEN

This update aimed to review the new evidence available to support or refute prior Allergic Rhinitis and its Impact on Asthma (ARIA) statements. A Medline search of publications between 2000 and 2005 was conducted, with articles selected by experts. New evidence supports previous ARIA statements, such as: (i) allergic rhinitis (AR) is a risk factor for asthma; (ii) patients with persistent rhinitis should be evaluated for asthma; (iii) most patients with asthma have rhinitis; (iv) a combined strategy should be used to treat the airways and (v) in low- to middle-income countries, a different strategy may be needed. The increased risk of asthma has also been found among sufferers from non-AR. Recent reports show AR is a global problem. Many studies demonstrated parallel increasing prevalence of asthma and rhinitis, but in regions of highest prevalence, it may be reaching a plateau. Factors associated with a reduced risk of asthma and AR have been identified, confirming previous findings of protection related to exposure to infections. Treatment of rhinitis with intranasal glucocorticosteroids, antihistamines, leukotriene antagonists or immunotherapy may reduce morbidity because of asthma. To take advantage of the paradigm of unified airways, there is a need to rationalize diagnosis and treatment to optimize management.     

Desloratadine reduces systemic allergic inflammation following nasal provocation in allergic rhinitis and asthma patients

BACKGROUND: Preclinical studies have demonstrated that some second-generation antihistamines have anti-inflammatory effects. It is not known whether these effects are also demonstrable in vivo. In this study we investigated the effect of treatment with desloratadine (DL) on systemic inflammation and on nasal and bronchial mucosal inflammation after nasal allergen provocation (NP) in subjects with grass-pollen-allergic rhinitis and asthma. METHODS: Twenty-six subjects with grass-pollen-allergic rhinitis and asthma were randomly allocated to 8 days of treatment with DL (n = 13) or placebo (n = 13) outside the grass pollen season. On day 7 they underwent nasal provocation with grass pollen allergen. Nasal and bronchial biopsies were taken for immunohistochemical evaluation, and blood samples were analysed. Rhinitis and asthma symptoms, peak nasal inspiratory flow and peak expiratory flow, were also measured at specified times. RESULTS: The number of circulating eosinophils decreased during DL treatment, and there was a reduced increase in circulating eosinophils after NP in these subjects. There was also a significant reduction in early bronchial clinical response. There was no significant lessening in the severity of the nasal symptoms. Nasal and bronchial mucosal inflammation parameters did not alter under DL treatment. CONCLUSION: These data suggest that treatment with DL reduces systemic eosinophilia and prevents the increase in circulating eosinophils after NP. DL also significantly reduces the early bronchial clinical response to NP. However, airway mucosal inflammation is not altered by 1 week of treatment.     

Sinonasal pathology in nonallergic asthma and COPD: 'united airway disease' beyond the scope of allergy

Background:  In contrast to the epidemiological and clinical association between allergic rhinitis and asthma, upper airway inflammation is less characterized in patients with nonatopic asthma and virtually unexplored in chronic obstructive pulmonary disease (COPD). Here, sinonasal pathology is studied in patients with allergic asthma, nonallergic asthma and COPD.
Methods:  Ninety patients with stable bronchial disease were included in the study, of which 35 were diagnosed with allergic asthma, 24 with nonallergic asthma and 31 with COPD. Concurrently, 61 control subjects without pulmonary disease were included and matched for age and smoking habits respectively with the asthma and the COPD group. Sinonasal symptoms were evaluated on a visual analogue scale and rhinosinusitis-related impairment of quality of life was assessed with the sino-nasal outcome test-22 (SNOT-22) questionnaire. Nasal mucosal abnormalities were quantified with nasal endoscopy and nasal secretions collected for measuring inflammatory mediators.
Results:  Allergic asthmatics, nonallergic asthmatics and COPD patients reported more nasal symptoms than their respective control subjects, had a higher SNOT-22 score and presented more mucosal abnormalities in the nose. Nasal secretions of both allergic and nonallergic asthmatics contained higher levels of eotaxin, G-CSF, IFN-γ and MCP-1 than controls. Allergic asthmatics had higher nasal IP-10 levels as well. COPD-patients had higher nasal levels of eotaxin, G-CSF and IFN-γ than controls.
Conclusion:  Patients with allergic and nonallergic asthma and COPD show increased nasal symptoms and more nasal inflammation. Hence, our data confirm the 'united airways' concept to be beyond the scope of allergic asthma.     

Intranasal and inhaled fluticasone propionate for pollen-induced rhinitis and asthma

BACKGROUND: Studies suggest that nasal treatment might influence lower airway symptoms and function in patients with comorbid rhinitis and asthma. We investigated the effect of intranasal, inhaled corticosteroid or the combination of both in patients with both pollen-induced rhinitis and asthma. METHODS: A total of 262 patients were randomized to 6 weeks' treatment with intranasal fluticasone propionate (INFP) 200 microg o.d., inhaled fluticasone propionate (IHFP) 250 microg b.i.d., their combination, or intranasal or inhaled placebo, in a multicentre, double-blind, parallel-group study. Treatment was started 2 weeks prior to the pollen season and patients recorded their nasal and bronchial symptoms twice daily. Before and after 4 and 6 weeks' treatment, the patients were assessed for lung function, methacholine responsiveness, and induced sputum cell counts. RESULTS: Intranasal fluticasone propionate significantly increased the percentages of patients reporting no nasal blockage, sneezing, or rhinorrhoea during the pollen season, compared with IHFP or intranasal or inhaled placebo. In contrast, only IHFP significantly improved morning peak-flow, forced expiratory volume in 1 second (FEV1) and methacholine PD20, and the seasonal increase in the sputum eosinophils and methacholine responsiveness. CONCLUSIONS: In patients with pollen-induced rhinitis and asthma, the combination of intranasal and IHFP is needed to control the seasonal increase in nasal and asthmatic symptoms.     

Arsenic trioxide alleviates airway hyperresponsiveness and eosinophilia in a murine model of asthma

Asthma is one of the most common chronic airway inflammatory diseases. The clinical hallmarks of asthma include elevated serum levels of immunoglobulin E (IgE), eosinophilic inflammation and airway hyper-responsiveness (AHR). Arsenic trioxide (As₂O₃) is considered a carcinogen; however, it has also been used to treat diseases, such as syphilis, in traditional Chinese and Western medicine. Today, As₂O₃ is used as one of the standard therapies for acute promyelocytic leukemia (APL). Previous studies have indicated that As₂O₃ can induce apoptosis in eosinophils. However, the effect of As₂O₃ on asthma has not been investigated. We used ovalbumin (OVA)-immunized mice as a model for asthma and treated mice with As₂O₃ at doses of 2.5 and 5 mg/kg. The mice were then monitored for OVA-specific IgE production, airway inflammatory cell infiltration and AHR. We found that administration of As₂O₃ in OVA-immunized mice abrogated airway eosinophil recruitment by downregulating eotaxin expression but did not alter serum IgE or IL-5 levels in bronchoalveolar lavage fluid (BALF). Furthermore, the development of AHR and cellular infiltration into the airway were reduced by treating mice with As₂O₃. In vitro data suggested that low concentrations of As₂O₃ could induce only a small degree of apoptosis in primary pulmonary cells but could significantly inhibit the secretion of eotaxin by these cells. These results indicate that the administration of As₂O₃ to OVA-immunized mice can suppress lung allergic inflammatory responses. As₂O₃ might therefore have therapeutic potential in treating allergic airway inflammatory diseases.     

Allergic rhinitis in children with asthma: a questionnaire-based study

Background Allergic rhinitis (AR) and asthma frequently coexist but has rarely been evaluated in children. Objective This prospective study aimed to estimate the prevalence of AR in asthmatic children, and ascertain whether AR is a risk factor for the severity of asthma. Methods The questionnaire, modified from the adult form of the score for allergic rhinitis (SFAR), was completed by 404 asthmatic children aged 3–18 years seen in the outpatient clinic between June 2005 and July 2007. Each item was assigned a number of points with a final score ranging from 0 to 17. AR and asthma were classified according to ARIA and GINA 2004 recommendations, respectively. Results AR was diagnosed in 237 patients (58.7%). It was intermittent in 57.8% of the patients and persistent in 42.2%. A total score 9 was discriminant for AR (sensitivity=91.1%, specificity=95.2%, positive predictive value=96.4%, negative predictive value=88.3%, Youden's Index=0.86). The proportion of children having mild or moderate‐to‐severe asthma was independent of the presence of AR, 61.6% of moderate‐to‐severe asthmatic children and 55.4% of intermittent and mild asthmatic children having AR. Conclusion AR and asthma are frequently associated (58.7%). The SFAR adapted for children seems to be a simple and a reliable tool to detect AR in asthmatic children.     

Lower airway inflammatory responses to repeated very-low-dose allergen challenge in allergic rhinitis and asthma

BACKGROUND: Low-dose allergen challenge (LDAC) may be a useful tool for studying the capacity of allergens to induce airway inflammation in atopic subjects. OBJECTIVE: To evaluate lower airway inflammatory changes following repeated inhalation of very low doses of allergen (VLDAC) in non-asthmatic subjects with allergic rhinitis (NAAR) compared with mild allergic asthmatic subjects (AA). METHODS: Fourteen NAAR and 11 AA were seen out of the pollen season and had skin prick tests with common aeroallergens. Baseline spirometry (S) and methacholine challenge (MC) were done and blood and induced sputum (IS) differential cell counts were obtained. Each subject underwent VLDAC on four consecutive mornings with a relevant allergen. S, MC, and blood and IS samplings were repeated 6 h after the second and fourth VLDAC and one week later. RESULTS: Although there were, as expected, no changes in FEV1 or PC20 in either group, mean percentage eosinophils on IS were significantly increased in NAAR on day 2 of VLDAC and decreased in all but one subject on day 4, with a tendency to return to baseline levels one week later. In AA, there was a non-significant trend for sputum eosinophils to increase on day 2; four subjects showed a decrease of eosinophils on day 4 of VLDAC. There was a correlation between eosinophil cationic protein (ECP) levels and eosinophil counts in NAAR throughout the study. There were no variations in other sputum cells or blood inflammatory cells. CONCLUSION: VLDAC can increase the percentage of eosinophils in IS of NAAR subjects without associated respiratory symptoms nor physiological modifications. A reduction in eosinophilic response despite repeated exposure, more common in NAAR subjects, suggests an adaptation process that needs to be further evaluated.     

Airway inflammation in asthma and perennial allergic rhinitis. Relationship with nonspecific bronchial responsiveness and maximal airway narrowing

BACKGROUND: Eosinophilic airway inflammation is the hallmark of asthma, but it has also been reported in other conditions such as allergic rhinitis. We have tested whether the analysis of cells and chemicals in sputum can distinguish between patients with mild allergic asthma, those with allergic rhinitis, and healthy controls. The relationship between inflammation markers in sputum and nonspecific bronchial hyperresponsiveness to methacholine (BHR) (PD20 and maximal response plateau [MRP] values) was also evaluated. METHODS: We selected 31 mild asthmatics and 15 rhinitis patients sensitized to house-dust mite. As a control group, we studied 10 healthy subjects. Every subject underwent the methacholine bronchial provocation test (M-BPT) and sputum induction. Blood eosinophils and serum ECP levels were measured. Sputum cell differentials were assessed, and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin (IL)-5 levels were measured in the entire sputum supernatant. RESULTS: Blood eosinophils and serum ECP levels were higher in asthma patients and rhinitis than in healthy controls, but no difference between asthma patients and rhinitis patients was found. Asthmatics had higher eosinophil counts and higher ECP and tryptase levels in sputum than rhinitis patients or control subjects. Sputum albumin levels were higher in asthmatics than in controls. Rhinitis patients exhibited higher sputum eosinophils than healthy controls. An association between sputum eosinophil numbers and MPR values (r= -0.57) was detected, and a trend toward correlation between sputum ECP levels and PD20 values (r= -0.47) was found in the rhinitis group, but not in asthmatics. No correlation between blood eosinophilic inflammation and lung functional indices was found. CONCLUSIONS: Induced sputum is an accurate method to study bronchial inflammation, allowing one to distinguish between rhinitis patients and mildly asthmatic patients. The fact that no relationship was detected between sputum inflammation and BHR suggests that other factors, such as airway remodeling, may be at least partly responsible for BHR in asthma.     

Airway function and nasal inflammation in seasonal allergic rhinitis and asthma

BACKGROUND: Allergic rhinitis (AR) and asthma are frequently associated and characterized by a Th2-dependent inflammation. Nasal and bronchial obstruction may be objectively measured. OBJECTIVE: The aim of this study was to evaluate the relationships among upper and lower airway function and nasal inflammation in subjects with seasonal allergic rhinitis (SAR) and asthma. METHODS: Twenty out-patients (12 males and eight females, mean age: 23.4+3.6 years) with SAR and asthma were evaluated during the pollen season. All of them showed a moderate-severe grade of nasal obstruction. Total symptom score, rhinomanometry, spirometry, nasal lavage, and nasal scraping were obtained in all subjects. Eosinophils were counted by conventional staining; IL-4 and IFN-gamma were measured by immunoassay on fluids recovered from nasal lavage. RESULTS: Functional parameters, i.e. nasal airflow and forced expiratory volume in 1 s (FEV(1)), were correlated with nasal eosinophils (R(2)>0.83, P<0.001). Inflammatory parameters, i.e. eosinophils were correlated with immunological parameters, i.e. IL-4 and IFN-gamma levels (R(2)=0.93, P<0.001). Nasal symptoms were correlated with nasal airflow (rho=-0.71, P< or =0.01) and eosinophils (rho=0.72, P<0.01). Nasal airflow was correlated with FEV(1) (r=0.89, P<0.0001). CONCLUSIONS: This study demonstrates the close connection between Th2 cytokines and eosinophil infiltration in the nose. There is also clear evidence concerning the relationships between eosinophils infiltration and cytokines levels. Nasal eosinophils can be regarded as the most important predictors of upper and lower airway functions. These findings constitute first evidence of a relationship among nasal Th2-related inflammation and nasal and bronchial airflow in patients with SAR and asthma.     

Atopic and non-atopic allergic disorders: current insights into the possible involvement of free immunoglobulin light chains

Allergic diseases have become a serious global health problem in the developed world. IgE interacting with its high-affinitiy receptor FcɛRI is considered a major contributing factor to most types of allergies, but depending on the type of allergy, however, a subgroup of patients displays common symptoms and yet lack elevated levels of total serum IgE and/or antigen-specific IgE. Novel therapeutic strategies such as anti-IgE therapy may therefore not be applicable to these patients. It is clear, however, that these patients do display activation of mast cells. In several patients suffering from immunological disorders, an increase in free immunoglobulin (IG) light chain levels can be detected. Previously, we have described the capability of free light chains to elicit immediate hypersensitivity responses. In this Opinion article, we will discuss the role of IgE- and non-IgE-mediated mechanisms in allergic disorders and point out a possible role of free IG light chains in the pathogenesis of the non-atopic types of these allergies.     

Allergic rhinitis and asthma comorbidity: ARIA classification of rhinitis does not correlate with the prevalence of asthma

BACKGROUND: Allergic rhinitis and asthma comorbidity is supported by both the similar underlying pathogenesis and immunologic mechanisms. The aim of this study was to verify whether the characteristics of rhinitis classified according to the new Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines correlate with the prevalence of asthma. METHODS: From 1 March to 30 June 2002, a multi-centre cross-sectional study was conducted by 154 allergists chosen from throughout Italy. Duration, severity of rhinitis (according to the ARIA classification) and the type of allergic sensitizations were compared with the prevalence of asthma. RESULTS: One thousand three hundred and twenty-one consecutive rhinitis-allergic patients aged 18 years or older were enrolled for the study. The majority of patients, 1060 (80.24%), were on medication at the time of their specialist visit. Mild intermittent rhinitis was diagnosed in 7.7% of patients, moderate/severe intermittent in 17.1%, mild persistent in 11.6%, and moderate/severe persistent in 63.6%. The prevalence of asthma was 48% in patients with mild intermittent rhinitis, 49.6% in moderate-severe intermittent rhinitis, 36.6% in mild persistent rhinitis and 47.5% in moderate severe persistent patients. No correlation between the ARIA categories of rhinitis and the prevalence of asthma was found. A multivariate analysis, after adjustment for age, sex, type of sensitization, level of severity and duration of rhinitis classified according to the ARIA guidelines, demonstrated that age, over 41 years [risk ratio (RR) 1.260, 95% confidence interval (CI) 1.072-1.482] and especially over 51 years (RR 1.460, 95% CI 1.237-1.723), sensitization to indoor allergens (mite and cat), (RR 1.203, 95% CI 1.060-1.366), and polysensitization (RR 1.178, 95% CI 1.004-1.383) are significant risk factors for asthma. CONCLUSION: In allergic rhinitis (AR) patients referred to a specialist, the features of AR as defined by the ARIA classification are not able to predict the presence of asthma, therefore all such patients should be assessed for asthma.     

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'.     

Allergic rhinitis and asthma comorbidity in a survey of young adults in Italy

BACKGROUND: Several studies have provided evidence of a strong association between asthma and allergic or nonallergic rhinitis, leading to the hypothesis that allergic rhinitis (AR) and asthma represent a continuum of the same disease. AIM: The aims of our study were: (i) to measure the comorbidity of AR and asthma and asthma-like symptoms and (ii) to assess whether asthma, AR, and their coexistence share a common pattern of individual risk factors. METHODS: The subjects are participants from the Italian multicentre, cross-sectional survey on respiratory symptoms in the young adult general population (Italian Study of Asthma in Young Adults, ISAYA). The relationship between individual risk factors and asthma, AR and their coexistence, was studied by means of a multinomial logistic regression. RESULTS: About 60% of asthmatics reported AR. On the other hand, subjects with AR presented an eightfold risk of having asthma compared to subjects without AR. Age was negatively associated with asthma [OR = 0.89, 95% confidence interval (CI): 0.82-0.96], AR (OR = 0.92, 95% CI: 0.86-0.98), and asthma associated with AR (OR = 0.83, 95% CI: 0.79-0.88). The risk of AR without asthma was significantly higher in the upper social classes (OR = 1.23, 95% CI: 1.08-1.39). Active current smoking exposure was positively associated with asthma alone (OR = 1.24, 95% CI: 1.09-1.41) and negatively associated with AR with (OR = 0.69, 95% CI: 0.54-0.88) or without (OR = 0.76, 95% CI: 0.69-0.84) asthma. CONCLUSIONS: Asthma and AR coexist in a substantial percentage of patients; bronchial asthma and AR, when associated, seem to share the same risk factors as AR alone while asthma without AR seems to be a different condition, at least with respect to some relevant risk factors.