Comparison of early and late asthmatic responses between patients with allergic rhinitis and mild asthma

Pulmonary function and airway responsiveness in young competitive swimmers

RATIONALE

Strong physical activities are often associated with large lung volumes and relatively reduced flow, which may represent a physiological variant but also an obstructive abnormality. Competitive swimmers have also spirometric values even larger than other athletes, although they are at increased risk for asthma or airway hyperresponsiveness.

AIM

We aimed to investigate whether lung volumes increase with duration of swimming training and are related to an obstructive abnormality associated with airway hyperresponsiveness and asthma-like symptoms.

METHODS

Forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), airway responsiveness, and skin prick test were measured in 34 children/adolescents (age: 7-19 yrs old) trained for competitive swimming. Their "lifetime" exposure, i.e., the hours spent in pool was very strongly correlated with their age at the time of study. The effect of swimming activity was therefore estimated from the relationships between lung function data and age.

RESULTS

FVC Z-score was positively correlated with age, indicating that absolute values increased more than expected with normal growth, but FEV(1)/FVC was negatively correlated with age. Although the majority of subjects had allergic sensitization to aeroallergens and about one half had asthma-like symptoms and/or airway hyperresponsiveness, these conditions did not alter the relationships between lung function and age.

CONCLUSION

Intense swimming activity may cause a greater than normal lung growth, irrespective of the presence of allergic sensitization or airway hyperresponsiveness. The associated reduction of FEV(1) /FVC may represent a physiological variant rather than a true obstructive abnormality.

Plasma protein profiles in early asthmatic responses to inhalation allergen challenge

Although mediators, such as lipids, cytokines, and chemokines, are related to the appearance of an IPR, there has been no reliable indicator to predict conditions for the appearance of an IPR. In this study, we adopted a proteomic approach to investigate the pathogenesis at the level of the plasma proteins and to develop plasma markers to predict the appearance of an IPR following an inhalation challenge with Dermatophagoides pteronyssinus (D.p.). Sixteen mild asthmatics were recruited. Plasma was obtained before challenge and when a decline in forced expiratory volume in 1 s (FEV(1)) values greater than 20% from the phosphate-buffered saline value was achieved during D.p. allergen challenge (positive responders), or at 60 min after the highest concentration of D.p. allergen was inhaled (negative responders). After comparing normalized volumes of the spots in the two groups, differentially expressed spots were identified using intra-gel digestion and mass spectrometric analysis. Before D.p. antigen challenge, four spots of gamma fibrinogen and its isoforms were significantly decreased and two spots of complement C3 fragments were significantly increased in the positive responders compared to the negative responders. After D.p. antigen challenge, complement C3 fragment was persistently higher, while gamma fibrinogen was lower in the positive responders than in the negative responders. A validation study using Western blotting showed that gamma fibrinogen expression in the IPR-positive asthmatics was significantly decreased compared to the average of the IPR-negative asthmatic control group. These results indicate that alterations in the complement cascade and fibrinogen may predispose patients to the appearance of an immediate response to D.p. allergen challenge and may provide plasma markers to predict the appearance of an IPR.

Introduction to nasal and pulmonary allergy cascade

The early phase of an IgE-dependent allergic reaction is followed by the activation of a complex network of inflammatory phenomena - T lymphocytes, cytokines, mediators, and adhesion molecules - that mediate late and ongoing allergic symptoms. The kinetics of respiratory inflammation following allergen exposure involve the migration of inflammatory cells to the mucosa within about 30 min, increased inflammatory infiltration over the following hours, and then slow subsidence. A relationship between asthma and allergic rhinitis is supported by epidemiological, histological, physiological, and immunopathological data, and by the response of asthma symptoms in rhinitic patients to intranasal corticosteroids and antihistamines. For example, there is no morphological difference between the bronchial inflammatory response following allergen-specific challenge in patients suffering from asthma alone or rhinitis alone. It is the allergen dose that makes the difference in the airway response to allergen in allergic rhinitis and asthma. Recognition of the relationship between asthma and allergic rhinitis has led to the introduction of new diagnostic terminology and treatment recommendations: 1) patients with persistent rhinitis should be evaluated for asthma; 2) patients with persistent asthma should be evaluated for rhinitis; and 3) a strategy should combine the treatment of upper and lower airways in terms of efficacy and safety.

Inflammatory and mechanical factors of allergen-induced bronchoconstriction in mild asthma and rhinitis

We studied whether different bronchial responses to allergen in asthma and rhinitis are associated with different bronchial inflammation and remodeling or airway mechanics. Nine subjects with mild asthma and eight with rhinitis alone underwent methacholine and allergen inhalation challenges. The latter was preceded and followed by bronchoalveolar lavage and bronchial biopsy. The response to methacholine was positive in all asthmatic but in only two rhinitic subjects. The response to allergen was positive in all asthmatic and most, i.e., five, rhinitic subjects. No significant differences between groups were found in airway inflammatory cells or basement membrane thickness either at baseline or after allergen. The ability of deep inhalation to dilate methacholine-constricted airways was greater in rhinitis than in asthma, but it was progressively reduced in rhinitis during allergen challenge. We conclude that 1) rhinitic subjects may develop similar airway inflammation and remodeling as the asthmatic subjects do and 2) the difference in bronchial response to allergen between asthma and rhinitis is associated with different airway mechanics.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The association of sensitization to inhalant allergens with allergy symptoms: the influence of bronchial hyperresponsiveness and blood eosinophil count

BACKGROUND

We investigated whether the association of allergy symptoms with sensitization to inhalant allergens depends on bronchial hyperresponsiveness, blood eosinophil count, or the degree and nature of sensitization.

METHODS

Data on asthma and rhino-conjunctivitis symptoms were obtained from 1904 subjects from a random sample of the Dutch population, aged 20-70 years by the ECRHS questionnaire. Total IgE and specific IgE to four inhalant allergens were measured using CAP System. Bronchial hyperresponsiveness (BHR) was defined as PD20 </= 2 mg methacholine and 'high eosinophil count' as an eosinophil count in the highest quartile.

RESULTS

Forty-three percent of the subjects with specific IgE to inhalant allergens was asymptomatic. These subjects had a lower degree of sensitization than symptomatic sensitized subjects and had 'normal' prevalences of BHR and 'high eosinophil count'. Logistic regression showed that the presence of BHR increased the risk of having symptoms for subjects who were sensitized to indoor allergens. Low levels of specific IgE to indoor allergens were only associated with symptoms when BHR was present. Sensitization to outdoor allergens was associated with symptoms at all levels of specific IgE, independently of BHR or eosinophils.

CONCLUSION

Our epidemiological data suggest that whether low levels of specific IgE to indoor allergens lead to allergic symptoms is probably determined by the concurrent existence of inflammation of the airways.

Comparison of allergen-induced changes in bronchial hyperresponsiveness and airway inflammation between mildly allergic asthma patients and allergic rhinitis patients

Bronchial eosinophilic inflammation and bronchial hyperresponsiveness (BHR) are the main features of allergic asthma (AA), but they have also been demonstrated in allergic rhinitis (AR), suggesting a continuity between both diseases. In spite of not fully reproducing natural allergenic exposure, the allergen bronchial provocation test (A-BPT) has provided important knowledge of the pathophysiology of AA. Our aim was to verify the existence of a behavior of AA and AR airways different from the allergen bronchial challenge-induced airway eosinophilic inflammation and BHR changes. We studied a group of 31 mild and short-evolution AA and 15 AR patients, sensitized to Dermatophagoides pteronyssinus. The A-BPT was performed with a partially biologically standardized D. pteronyssinus extract, and known quantities of Der p 1 were inhaled. Peripheral blood (eosinophils and ECP) and induced sputum (percentage cell counts, ECP, albumin, tryptase, and interleukin [IL]-5) were analyzed, before and 24 h after A-BPT. Methacholine BHR, assessed before and 32 h after the A-BPT, was defined by M-PD20 values and, when possible, by maximal response plateau (MRP). The A-BPT was well tolerated by all the patients. AA presented a lower Der p 1 PD20 and a higher occurrence of late-phase responses (LPR). M-PD20 values decreased in AA, but not in AR, patients. MRP values increased in both groups. Eosinophils numbers and ECP levels increased in blood and sputum from both AA and AR, but only the absolute increment of sputum ECP levels was higher in AA than AR patients (P = 0.025). The A-BPT induced no change in sputum albumin, tryptase, or IL-5 values. We conclude as follows: 1) In spite of presenting a lower degree of bronchial sensitivity to allergen, AR patients responded to allergen inhalation with an eosinophilic inflammation enhancement very similar to that observed among AA. 2) MRP levels increased in both AA and AR patients after allergen challenge; however, M-PD20 values significantly changed only in the AA group, suggesting that the components of the airway response to methacholine were controlled by different mechanisms. 3) It is possible that the differences between AR and AA lie only in the quantitative bronchial response to allergen inhalation.

Eosinophils are a feature of upper and lower airway pathology in non-atopic asthma, irrespective of the presence of rhinitis

BACKGROUND

Asthma and rhinitis often co-exist and there are data to suggest that they may be two ends of the same disease spectrum. Immunohistochemical studies have shown that eosinophilia in the airways is a feature of rhinitic patients without asthma.

OBJECTIVE

The aim of our study was to examine whether cellular infiltration exists in the nasal mucosa of asthmatics even in the absence of symptoms and signs of rhinitis.

METHODS

Nasal mucosa biopsies were taken from 27 non-atopic subjects and comprised nine asthmatic rhinitic patients (AR), eight asthmatic non-rhinitic patients (ANR) and 10 healthy control subjects (N). Bronchial mucosa biopsies were also taken simultaneously from some of the patients (n = 10) to determine whether there was an association between cellular infiltration in the nose and the lungs. The alkaline phosphatase-anti-alkaline phosphatase (APAAP) method was used on 6 microm thick cryostat sections using monoclonal antibodies against T cells (CD4, CD8), eosinophils (EG2) and mast cells (mast cell tryptase). Slides were counted blind and results expressed as cells per field.

RESULTS

The results showed that eosinophil counts were higher in both asthma groups compared with control nasal biopsies (median values AR 8.3, ANR 9.2, N 2.1 cells per field, P < 0.01). Furthermore, there was a significant correlation between eosinophil cell counts in the nose and the airways (r = 0.851 P < 0.001). No differences in eosinophil numbers were detected between the two groups of asthmatics. Also, no differences were noted for any other cell type (i.e. CD4, CD8, tryptase) among the three study groups.

CONCLUSIONS

These results show that eosinophil infiltration was present in the nasal mucosa of asthmatic patients even in the absence of rhinitis, and add further support to the hypothesis that asthma and rhinitis are clinical expressions of the same disease entity.

Non-specific nasal and bronchial reactivity are not correlated in non-asthmatic subjects occupationally exposed to irritants and in healthy subjects

BACKGROUND

Non-specific nasal and bronchial reactivity are frequently correlated in disease (rhinitis and asthma). It is not known whether such a correlation exists in subjects exposed to irritants and in healthy subjects. In order to test the hypothesis that a correlation between non-specific nasal and bronchial reactivity exists in non-asthmatic subjects, two groups of subjects were studied: 110 workers occupationally exposed to respiratory irritants, and 86 non-exposed healthy controls.

METHODS

Allergy, non-specific nasal, and non-specific bronchial reactivity were tested, and smoking habits were categorized in each subject.

RESULTS

Respiratory irritants cause a substantial increase in nasal and bronchial reactivity when compared with the group of healthy, non-exposed subjects (33.6% nasal hyperreactors and 20.0% bronchial hyperreactors vs. 4.7% nasal hyperreactors and 2.3% bronchial hyperreactors, respectively). But, occupational exposure to respiratory irritants does not induce a correlation between non-specific nasal and bronchial reactivity frequently found in asthmatic and rhinitic subjects.

CONCLUSIONS

We found no correlation between non-specific nasal and bronchial reactivity either in subjects occupationally exposed to respiratory irritants or in the group of healthy subjects. This lack of correlation in both studied groups seems to be a feature of non-diseased airways. Smoking as an additional factor does not increase nasal and bronchial reactivity either in workers exposed to irritants or in healthy subjects. Smoking also does not strengthen the correlation between upper and lower airways' reactivity in both groups.

A comparison of the onset of action of salbutamol and formoterol in reversing methacholine-induced bronchoconstriction

This single-centre, randomized, double-blind, double-dummy four-way cross-over study in 24 moderately severe asthmatic patients compared the speed of onset of recommended doses of salbutamol (200 micrograms) and formoterol (12 micrograms) delivered by metered-dose inhaler in reversing the bronchoconstriction induced by a cumulative dose of methacholine to produce a 20% decrease (PD20) in forced expiratory volume in 1 s (FEV1). Specific airway conductance (SGAW) and airway resistance (RAW) were measured in baseline condition, immediately after challenge and 0.5, 1.5, 3, 5, 10, 15, 30, 60 min and every hour up to 4 h after inhalation of the trial drug. FEV1 was measured in baseline condition, after challenge and 15, 30 and 60 min and then every 30 min up to 4 h after inhalation of the study drug. The primary efficacy parameter was the change in SGAW. Salbutamol produced a two-fold increase in SGAW within 4 min and a maximum increase after 79.3 min. Formoterol produced a two-fold increase in SGAW after 5 min and a maximum increase after 119.6 min. Changes in SGAW were slightly, but consistently, higher during the first 2 h after inhalation of salbutamol, both in absolute values and as a percentage of the maximum response. Differences were significant at 10, 15 and 30 min time points. There was no significant difference between the maximum values of SGAW after the two drugs. Changes in RAW and FEV1 reflected the differences in SGAW. It was concluded that in methacholine-induced bronchoconstriction both formoterol and salbutamol have a very fast onset of action, achieving prechallenge values of SGAW within 3 min, salbutamol being slightly faster than formoterol.