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 inflammation and cough sensitivity in cough-variant asthma

BACKGROUND: Mechanisms underlying cough and bronchoconstriction in patients with cough-variant asthma (CVA) are not well established. Differences in location or degree of activation of eosinophils and allergic cytokines have been suggested as the likely causes. To address this issue, we have carried out a comparative study of airway inflammatory markers between patients with CVA and classic asthma (CA). The relationship between these markers with airway hyperresponsiveness (AHR) and cough sensitivity has also been studied. METHODS: Twenty-seven non-smokers and steroid-naive patients with CVA (12) and CA (15) were examined. Capsaicin challenge, histamine bronchoprovocation test, nitric oxide levels in exhaled air and sputum induction were performed in all of them. Differential cell sputum recount and supernatant concentrations of eosinophil granule-derived cationic proteins (ECP), interleukin (IL)5, IL8 and tumour necrosis factor (TNF)-alpha were also measured. RESULTS: There were no significant differences in either the inflammatory pattern of soluble markers or differential cell counts between CA and CVA. Histamine PC20 was correlated with IL-5 in CVA, whereas it was associated with sputum eosinophilia in CA. Cough sensitivity (log C5) and histamine PC20 were inversely related in CA. CONCLUSIONS: Although the pattern of inflammatory sputum markers in patients with asthma and cough-variant asthma is similar, its relation with bronchial hyperreactivity and cough sensitivity is different in each group.     

The importance of maximal airway response to methacholine in the prediction of asthma development in patients with allergic rhinitis

BACKGROUND: Allergic rhinitis is a known predictor and correlate of asthma incidence. However, it is not clear which patients with allergic rhinitis are at greater risk of the development of asthma. OBJECTIVE: The aim of this study was to investigate whether airway hypersensitivity and/or increased maximal response on the dose-response curve to methacholine would predict the development of asthma in subjects with allergic rhinitis. METHODS: One hundred and forty-one children with allergic rhinitis were prospectively studied for 7 years. At the initiation of the study, bronchial provocation test with methacholine using a stepwise increasing concentration technique was performed to measure PC(20) (provocative concentration causing a 20% fall in FEV(1)) and maximal response. Each subject was evaluated at least every 6 months and details of asthmatic symptoms or signs experienced during the intervening period were taken. RESULTS: Twenty of 122 subjects available for the follow-up developed asthma. Nine (19.6%) of 46 hypersensitive (PC(20) < 18 mg/mL) subjects developed asthma, compared with 11 (14.5%) of 76 normosensitive subjects (P = 0.462). Eight (32%) of 25 subjects without maximal response plateau developed asthma, compared with 12 (12.4%) of 97 subjects with maximal response plateau (P = 0.018). Score test for trend revealed a significant association between the level of maximal response (P = 0.007), but not the degree of methacholine PC(20) (P = 0.123), and the future development of asthma. CONCLUSION: An increased maximal airway response to methacholine is shown to be a better predictor for the future development of asthma in patients with allergic rhinitis, than airway hypersensitivity to methacholine.     

Bronchial hyperresponsiveness and airway inflammation in adolescents with asymptomatic childhood asthma

BACKGROUND: About 70% of childhood asthmatics become free of asthma-related symptoms during adolescence. Little is known about bronchial hyperresponsiveness (BHR) and airway inflammation in young adults with "outgrown" childhood asthma. METHODS: We studied 61 nonsmoking medical students (18 intermittent mild asthmatics, 23 students with outgrown childhood asthma but free of asthma-related symptoms for 10 years (asymptomatic asthmatics) and 20 healthy students). BHR and lung function were measured, and induced sputum samples analyzed for eosinophil count, eosinophilic cationic protein (ECP), granulocyte-macrophage colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha). RESULTS: BHR was still present in most asymptomatic asthmatics, but it was milder compared with healthy students. Only three subjects with previous asthma had no BHR and no signs of airway inflammation. Percentages of eosinophil, and ECP, TNF-alpha and GM-CSF concentrations in induced sputum of mild asthmatics and asymptomatic asthma groups were higher than in the healthy group. In asymptomatic asthmatics group, the duration of asthma, sputum eosinophil percentage, and the level of TNF-alpha in sputum correlated significantly with BHR. CONCLUSIONS: Only a few subjects with longstanding asymptomatic asthma could be considered as cured; most asymptomatic asthmatics continued to exhibit BHR and signs of airway inflammation. The outcome of childhood asthma and BHR was associated with the degree of airway inflammation and the duration of childhood asthma.     

Inhaled vs subcutaneous effects of a dual IL-4/IL-13 antagonist in a monkey model of asthma

Background:  Pitrakinra is a recombinant protein derived from human interleukin-4 (IL-4) that binds to IL-4Rα and acts as a competitive antagonist of IL-4 and IL-13. The studies reported here compare the dose-ranging effects of pitrakinra on allergen-induced airway hyperresponsiveness (AHR) and airway eosinophilia when administered subcutaneously (s.c.) or by inhalation to the Ascaris suum -sensitive cynomolgus monkey for the purpose of elucidating the primary site of pitrakinra's anti-asthmatic action.
Methods:  Airway responsiveness to inhaled methacholine and bronchoalveolar lavage cell composition was determined before and after three allergen exposures with a 1-week course of twice-daily (b.i.d.) s.c. or inhaled pitrakinra or placebo treatment.
Results:  Treatment with s.c. pitrakinra significantly reduced allergen-induced AHR, with a maximum effect of a 2.8- to 3.8-fold increase in methacholine PC₁₀₀ relative to control ( P  < 0.05) observed at b.i.d. s.c. doses of 0.05–0.5 mg/kg. Inhaled pitrakinra also significantly reduced AHR with a similar maximum effect of a 2.8- to 3.2-fold increase in methacholine PC₁₀₀ relative to control ( P  < 0.05) at nominal b.i.d. doses of 3–100 mg. The maximal effect on AHR following inhalation was observed at a plasma concentration which exhibited no efficacy via the subcutaneous route. The effect of pitrakinra on lung eosinophilia was not statistically significant following either route of administration, although lung eosinophil count was reduced in all studies relative to control.
Conclusion:  Local administration of pitrakinra to the lung is sufficient to inhibit AHR, one of the cardinal features of asthma, indicating the therapeutic potential of inhaled pitrakinra in the treatment of atopic asthma.     

Effect of current exposure to Der p 1 on asthma symptoms, airway inflammation, and bronchial hyperresponsiveness in mite-allergic asthmatics

The existence of a dose-response relationship between indoor allergen exposure and sensitization has been widely described, but the effect of allergen exposure on asthma activity (symptoms, bronchial hyperresponsiveness [BHR], and inflammation) is not clear. Our aim was to determine the existence of an association among current exposure to mite allergens and symptoms, BHR, and airway inflammation assessed in blood and sputum from asthmatic patients sensitized to Dermatophagoides pteronyssinus. We selected 31 mild and recently diagnosed (12-24 months) asthma patients sensitized to D. pteronyssinus. Allergenic exposure (Der p 1, Der 2) was assessed by a commercial assay based on monoclonal antibodies (mAb), carried out on the dust samples collected from patients' beds in a standardized way. Patients completed an asthma symptom questionnaire and underwent skin tests, methacholine bronchial challenge, and sputum induction. Sputum cell profile was analyzed and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin(IL)-5 levels were quantified in sputum supernatant. Total eosinophil numbers and ECP levels were measured in blood samples. Most patients were exposed to Der p 1 levels under 2 microg/g of dust. Der p 1 exposure was higher among the subjects with positive sputum tryptase detection (P = 0.020). Der p 1 levels showed a trend toward correlation with asthma symptoms (P = 0.066, r = 0.36) and correlated with sputum tryptase levels (P = 0.032, r = 0.42). No relationship between BHR, eosinophilic inflammation, and allergenic exposure was found. Our results suggest that asthma symptoms and lung mast-cell activation are at least partially dependent on current allergen exposure. The lack of correlation between mite exposure, eosinophilic inflammation, and BHR supports the role of other factors that enhance the immunologic response initiated by allergen, increasing the activity of asthma.     

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.     

Occupational asthma in a grain worker due to Lepidoglyphus destructor, assessed by bronchial provocation test and induced sputum

BACKGROUND: Occupational asthma (OA) can be a debilitating disease even when removal from the workplace is achieved. Today, the "gold standard" in the assessment of OA is the bronchial provocation test (BPT). Induced sputum is a non-invasive method of exploring airway inflammation which can provide additional information about such challenges and thus could be applied in OA diagnosis and monitoring. METHODS: We report the study carried out in a grain worker sensitized to Lepidoglyphus destructor (Ld), who suffered from mild asthma at the workplace. Skin prick test and specific serum IgE were measured. Ld-BPT was performed, and the changes in eosinophil rates, and ECP and tryptase levels in induced sputum were studied 30 min and 18 h after Ld-BPT. We also determined the changes in nonspecific bronchial hyperresponsiveness (NSBH), given as PD20 values. To assess the specificity of the changes, we also carried out sputum induction and methacholine challenge after barley-BPT. RESULTS: An isolated immediate response was obtained with Ld-BPT, while barley-BPT was negative. Induced sputum showed higher tryptase levels 30 min after Ld-BPT, and higher eosinophil and epithelial cell percentages and ECP levels 18 h after Ld-BPT. There was also a decrease in methacholine PD20 values after Ld-BPT. Those changes were not observed after barley-BPT. CONCLUSIONS: The study of eosinophilic and mast-cell markers in induced sputum provides additional knowledge about the inflammatory process occurring in the airways, suggesting that the study of induced sputum should be considered in the assessment of OA.     

The importance of maximal airway response to methacholine in the prediction of wheezing development in patients with cough-variant asthma

BACKGROUND: A significant proportion of patients diagnosed with cough-variant asthma eventually manifest classic asthma signs, such as wheezing and dyspnea. The aim of this study was to investigate whether the degree of airway hypersensitivity and/or the level of maximal airway response can predict the development of wheezing in subjects with cough-variant asthma. METHODS: At study initiation, a high-dose methacholine inhalation test was performed to measure provocative concentration causing a 20% fall (PC20) in forced expiratory volume in 1 s (FEV1) and maximal airway response. Each person was evaluated regularly every 3 months for 4 years and also on the occasion of wheezing being perceived for the first time. RESULTS: Of the 48 patients available in the follow-up period, 21 (Group 1) developed clinical wheezing, while 27 (Group 2) did not. There was no significant difference in PC20 levels between the two groups. The level of maximal airway response, however, was significantly higher in Group 1 than in Group 2. The score test for trend revealed a significant association between the future development of wheezing and the level of maximal airway response (P = 0.007), but not the level of methacholine PC20 (P = 0.423). CONCLUSIONS: The level of maximal airway response, rather than the degree of airway hypersensitivity, may be an important risk factor for the future development of classic asthma in patients with cough-variant asthma.     

Effect of ethanol on airway caliber and nonspecific bronchial responsiveness in patients with alcohol-induced asthma

No study has investigated the effects of ethanol on bronchial responsiveness in patients with alcohol-induced asthma, although acetaldehyde, which is a metabolite of ethanol and is thought to be a main factor in alcohol-induced asthma, causes both bronchoconstriction and bronchial hyperresponsiveness. The purpose of this study was to investigate the direct action of ethanol on the airway in patients with alcohol-induced asthma. First, we investigated the bronchial response to inhalation of ascending doses (5, 10, and 20%) of ethanol in nine patients with alcohol-induced asthma. Then, the bronchial responsiveness to methacholine was measured in 14 patients who were pretreated with saline or 20% ethanol in a double-blind, randomized, placebo-controlled, crossover fashion. Ascending doses of inhaled ethanol caused no significant changes in FEV₁. The methacholine concentrations producing a 20% fall in FEV₁ (PC₂₀-MCh) after 20% ethanol (0.769 mg/ml, GSEM 1.514) were significantly ( P = 0.0357) higher than those after saline (0.493 mg/ml, GSEM 1.368). This indicates that ethanol has a reducing effect on nonspecific bronchial responsiveness in patients with alcohol-induced asthma; this paper is the first report on the effects of ethanol on bronchial responsiveness.     

Plasma histamine and bronchial reactivity in allergic asthma

Histamine is an important mediator of allergic inflammation and bronchial hyperresponsiveness (BHR), a hallmark of asthma. Studies on the relationship between plasma histamine and BHR in allergic asthmatic patients have yielded controversial results. We therefore measured plasma histamine and bronchial reactivity in 30 nonsmoker volunteers taking no medication. Eleven were normal subjects; 19 were stable, mildly allergic asthmatic patients. Venous blood was taken to measure blood cells and basal plasma histamine by radioimmunoassay. After blood sampling, all subjects underwent a measurement of PC₂₀M (concentration of methacholine causing a 20% fall in FEV₁). Mean plasma histamine levels were 0.21 ± 0.1 ng/ml and 0.44 ± 0.3 ng/ml in normal and asthmatic subjects, respectively (P<0.05). We found a significant increase of blood eosinophils and basophils in asthmatic patients, and a positive correlation between plasma histamine and circulating basophils. PC₂₀M was greater than 16 mg in normal volunteers, and mean PC₂₀M was 2.1 ± 2 mg/ml in asthmatic patients. PC₂₀M did not correlate with plasma histamine levels, but it did so negatively with blood eosinophils. The increased plasma histamine concentration in mildly atopic asthmatic patients might be a consequence of the high basophil releasability of atopies and the higher basophil counts in allergic asthma. Plasma histamine is thus unlikely to be a determinant of BHR in asthma.     

Sensitivity and maximal response to methacholine in perennial and seasonal allergic rhinitis

Background Airway hyperresponsiveness to pharmacological agonists is a common feature in subjects with allergic rhinitis.
Objective The aim of this study was to investigate differences in threshold value and shape of the concentration-response curves to methacholine between subjects with perennial allergic rhinitis and subjects with seasonal rhinitis.
Methods We studied a sample of 72 non-asthmatic patients with allergic rhinitis. They were subdivided into two groups: subjects with only seasonal symptoms and skin sensitization to grass and/or Parietaria pollen allergens (seasonal group, n = 38), and subjects with perennial symptoms and skin sensitization to house dust mite, alone or with other allergens (perennial group, n = 34). They were challenged with methacholine (up to 200mg/mL), and concentration-response curves were characterized by the threshold value (PC₂₀= provocative concentration of methacholine required to produce a 20% fall in FEV₁) and maximal response plateau, if possible. The measurements in the seasonal group were done within the pollen season.
Results The geometric mean methacholine PC₂₀ for subjects of the perennial group was 6.9mg/mL, compared with 23.4mg/mL in subjects of the seasonal group ( P 0.01). A plateau response was detected in 16 subjects of the perennial group and in 28 subjects of the seasonal group (p 0.05). Moreover, the level of plateau was higher in subjects of the perennial group when compared with subjects of the seasonal group (23.8 ±2.0% vs 19.2 ±1.6%, P 0.05).
Conclusion In subjects with allergic rhinitis, sensitization to perennial allergens is associated not only with lower methacholine threshold values, but also with lower prevalence and higher level of plateau than sensitization to pollen allergens.     

Eotaxin in induced sputum of asthmatics: relationship with eosinophils and eosinophil cationic protein in sputum

BACKGROUND: Eosinophilic inflammation is a crucial aspect of allergic diseases such as bronchial asthma. An eosinophil-active chemokine, eotaxin, may play a role in the pathogenesis of the tissue eosinophilia accompanying asthma. METHODS: Induced sputa were obtained from 53 patients with atopic asthma and six healthy subjects, and the concentration of eotaxin in the sputum was measured by ELISA. We investigated whether the sputum content of eotaxin is related to 1) asthma status or corticosteroid therapy, and 2) other sputum indices, including percentage of eosinophils and concentration of eosinophil cationic protein (ECP). RESULTS: The patients with stable or unstable asthma showed significantly higher concentrations of sputum eotaxin than the normal controls. The level of sputum eotaxin demonstrated a positive correlation with the percentage of eosinophils in stable asthmatics not receiving corticosteroid therapy, but not in stable patients treated with corticosteroids, or in unstable patients. Sputum eotaxin demonstrated a positive correlation with ECP in asthmatic patients who were either in a stable state or not receiving steroid therapy. CONCLUSIONS: The elevated level of eotaxin detected in association with increased eosinophils and ECP in the sputum of asthmatics suggests that eotaxin is involved in the pathogenesis of eosinophilic airway inflammation. The relationship of eotaxin to airway eosinophilia may be modified by the stability status of asthma and corticosteroid therapy.     

IL-12p40 is essential for the down-regulation of airway hyperresponsiveness in a mouse model of bronchial asthma with prolonged antigen exposure

Background We previously reported a mouse model of bronchial asthma showing eosinophilic inflammation, but not airway hyperresponsiveness (AHR), after prolonged antigen exposure. This model showed an increase of IL-12 in the lung.
Objective The aim of this study was to investigate the role of IL-12p40 in a murine asthma model with prolonged antigen exposures.
Methods An ovalbumin (OVA)-induced asthma model was first established in wild-type (WT) and IL-12p40-deficient (IL-12p40^−/−) mice. Both strains of mice were further exposed to either OVA (prolonged exposure group) or phosphate-buffered saline (positive control group) 3 days per week for 3 weeks. During week 4, both groups of mice were given a final challenge with OVA.
Results Prolonged antigen exposures resulted in marked suppression of airway eosinophilia in both WT and IL-12p40^−/− mice. However, AHR persisted in IL-12p40^−/− but not in WT mice. There were no significant differences of IL-5, IL-13 or IFN-γ levels in bronchoalveolar lavage fluid between WT and IL-12p40^−/− mice. The hydroxyproline content of the lung and peribronchial fibrosis were, however, significantly increased in IL-12p40^−/− mice.
Conclusion The results suggest that endogenous IL-12p40 is essential for inhibition of AHR and peribronchial fibrosis, but not eosinophilic inflammation, in a murine asthma model with prolonged antigen exposures.     

Sputum neurokinin A in Egyptian asthmatic children and adolescents: relation to exacerbation severity

Background:  Neurogenic inflammation may participate in the development and progression of bronchial asthma. The molecular mechanisms underlying neurogenic inflammation are orchestrated by a large number of neuropeptides including tachykinins such as neurokinin A (NKA) and substance P. Tachykinins are secreted from sensory airway nerves and inflammatory cells after allergens exposure. In clinical practice, assessment of airway inflammation is difficult. Therefore, detection of biological markers of airway inflammation in sputum might offer help for proper monitoring of asthma severity.
Aim of the study:  We aimed to measure sputum NKA in relation to acute asthma exacerbations of varying severity.
Methods:  Sputum NKA was measured by enzyme-linked immunosorbent assay in 24 children and adolescents during and after acute asthma exacerbation and 24 healthy matched controls.
Results:  Sputum NKA was significantly higher in asthmatic patients during acute exacerbation than controls [217.5 (284) vs 10 (7) ng/ml, P  < 0.001]. When patients with acute asthma exacerbation were followed-up till remission, sputum NKA levels decreased significantly, but they remained significantly higher than controls. Sputum NKA levels were significantly higher in severe than moderate and in moderate than mild exacerbations, and was negatively correlated to peak expiratory flow rate ( r  = −0.9, P  < 0.001). Sputum NKA had significant positive correlations to eosinophil counts in blood and sputum ( r  = 0.6, P  < 0.001 and r  = 0.7, P  < 0.001 respectively).
Conclusions:  Sputum NKA is up-regulated during acute asthma exacerbation and it positively correlates to its severity. Thus, NKA may aid in objective classification of the exacerbation severity. In addition, NKA may be a target for new asthma therapy.     

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate in young children with asthma: their relationship with blood eosinophils and serum eosinophil cationic protein

BACKGROUND: Bronchial hyperresponsiveness is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. Blood eosinophil numbers and serum levels of eosinophil cationic protein (ECP) are considered as indirect measures of airway inflammation in asthma. The aim of this study was to investigate whether bronchial responsiveness to adenosine 5'-monophosphate (AMP) is more closely associated with blood eosinophil markers, compared with that to methacholine, in young children with asthma. METHODS: Methacholine and AMP bronchial challenges were performed in 4- to 6-year-old children with asthma (n = 77) and in healthy controls (n = 32), using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. The peripheral blood eosinophil counts and serum ECP concentrations were determined in each subject. RESULTS: A positive response to methacholine (end-point concentration < or =8mg/ml) and to AMP (end-point concentration < or =200 mg/ml) was observed in 74 (96.1%) and 66 asthmatic children (85.7%), respectively. A majority of controls was unresponsive to both challenges. In the asthma group, there was no significant correlation between methacholine end-point concentration and the eosinophil counts (r = -0.111, P = 0.337) or serum ECP levels (r = -0.126, P = 0.274). In contrast, AMP end-point concentration correlated significantly with the eosinophil counts (r = -0.372, P = 0.001) and with serum ECP levels (r = -0.371, P = 0.001). CONCLUSIONS: Our results suggest that bronchial responsiveness to AMP is more closely related to airway inflammation, compared with that to methacholine, and support the potential usefulness of AMP challenges in detecting inflammatory changes in young children with asthma.     

Accuracy of eosinophils and eosinophil cationic protein to predict steroid improvement in asthma

BACKGROUND: There is a large variability in clinical response to corticosteroid treatment in patients with asthma. Several markers of inflammation like eosinophils and eosinophil cationic protein (ECP), as well as exhaled nitric oxide (NO), are good candidates to predict clinical response. AIM: We wanted to determine whether we could actually predict a favourable response to inhaled corticosteroids in individual patients. METHODS: One hundred and twenty patients with unstable asthma were treated with either prednisolone 30 mg/day, fluticasone propionate 1000 microg/day b.i.d. or fluticasone propionate 250 microg/day b.i.d., both via Diskhaler. They were treated during 2 weeks, in a double-blind, parallel group, double dummy design. We measured eosinophils and ECP in blood and sputum, and exhaled nitric oxide as inflammatory parameters before and after 2 weeks in order to predict the changes in forced expiratory volume in 1 s (FEV1), provocative concentration of methacholine causing a 20% fall in FEV1 (PC20 Mch), and asthma quality of life (QOL). Secondly, to test whether these results were applicable in clinical practice we determined the individual prediction of corticosteroid response. RESULTS: We found that changes in FEV1, PC20 Mch and QOL with corticosteroids were predominantly predicted by their respective baseline value and to a smaller extent by eosinophils in blood or sputum. ECP, measured in blood or sputum, was certainly not better than eosinophils in predicting clinical response to corticosteroids. Smoking status was an additional predictor for change in FEV1, but not for change in PC20 Mch or QOL. Prediction of a good clinical response was poor. For instance, high sputum eosinophils (> or = 3%) correctly predicted an improvement in PC20 Mch in only 65% of the patients. CONCLUSION: Our findings show that baseline values of the clinical parameters used as outcome parameters are the major predictors of clinical response to corticosteroids. Eosinophil percentage in blood or sputum adds to this, whereas ECP provides no additional information. Correct prediction of clinical response in an individual patient, however, remains poor with our currently used clinical and inflammatory parameters.     

Sputum eosinophil count in a large population of patients with mild to moderate steroid-naive asthma: distribution and relationship with methacholine bronchial hyperresponsiveness

BACKGROUND: Although airway eosinophilia is seen as a cardinal feature of asthma, data eosinophilia are still lacking on the proportion of the asthma group exhibiting raised airway eosinophilia. This study aimed to assess the distribution of sputum eosinophil count and its relationship with methacholine bronchial hyperresponsiveness in mild to moderate steroid-naive asthmatic people. METHODS: Sputum was induced by inhalation of hypertonic saline (NaCl 4.5%) in 118 mild to moderate steroid-naive asthmatic people consecutively recruited from our outpatient clinic, and in 44 healthy people. The asthma group was selected on the basis of an forced expiratory volume in 1 s (FEV(1)) of > or = 70% predicted, and a provocative methacholine concentration causing a fall of 20% in FEV(1) (PC20 methacholine; PC(20)M) < or = 16 mg/ml. RESULTS: In the asthma group, the median (range) of the percentage and the absolute values of sputum eosinophils were 4.8% (0-75) and 38 10(3)/g (0-14,191), respectively, vs 0% (0-2.3) (P < 0.001) and 0 10(3)/g (0-53) (P < 0.001) in healthy participants. Based on the 95% percentile for normal values calculated from our healthy group, 69% of the asthma group had significantly raised sputum eosinophil count (that is > 2%). In the asthma group, multiple regression analysis followed by a stepwise procedure revealed that sputum eosinophil count was significantly and inversely associated with PC(20)M accounting for 16% of its total variance (P < 0.001) while neutrophil counts positively related to PC(20)M accounting for 4% of total variance (P < 0.05). By contrast, no significant relationship was found between either eosinophil or neutrophil counts and the slope of forced vital capacity (FVC) vs FEV(1) from the methacholine challenge. CONCLUSIONS: We conclude that two-thirds of people in the mild to moderate asthma group had increased sputum eosinophilia, which plays a limited role in determining the degree of methacholine airway hyperresponsiveness.     

Serum eosinophil cationic protein (ECP) as a marker of disease activity and treatment efficacy in seasonal asthma

This study was carried out to determine whether serum eosinophil cationic protein (ECP) represents a sensitive marker for disease activity in atopic asthmatic patients during the pollen season. The study, in double-blind fashion, was performed between February and June 1994. Two groups of 10 seasonal asthmatic patients randomly received two different treatments. The first group was treated with inhaled beclomethasone dipropionate (BDP) 500 μg bid; the second received a matched placebo (P). At the beginning and every month, blood samples for determination of ECP and eosinophil count were collected and lung function (FEV₁) and methacholine responsiveness (PD₂₀) were performed. Subjects recorded daily symptoms of asthma, salbutamol consumption, and peak expiratory flow (PEF) values. In the P group, all indices, except FEV₁, showed significant changes during the pollen season ( P < 0.001). In the BDP group, significant changes were detected for symptom score ( P < 0.01), salbutamol consumption ( P < 0.01), and eosinophil number ( P < 0.05). Between the two groups, significant differences for symptom score ( P < 0.001), salbutamol consumption ( P < 0.001), ECP levels ( P < 0.05), eosinophil count ( P < 0.02), PD₂₀ methacholine ( P < 0.02), and PEF values ( P < 0.01) were detected. Changes in serum ECP significantly correlated with changes in other parameters ( P < 0.001), except FEV₁. Our results provide evidence that serum ECP is a sensitive marker for monitoring of the disease activity in seasonal asthma. Furthermore, it may offer a useful tool for estimating treatment efficacy.     

Comparison between hypertonic and isotonic saline-induced sputum in the evaluation of airway inflammation in subjects with moderate asthma

Background Hypertonic saline-indueed sputum has recently been used for the evaluation of airway inflammation in asthma. Objective To assess the effect of hypertonicity on airway inflammation. Methods We compared the inflammatory cell composition of hypertonic saline-induced sputum with that of isotonic saline-induced sputum in 21 asthmatic subjects and, at baseline and 30min after each sputum induction, we measured bronchial hyper-responsiveness to methacholine as an indirect marker to detect increased airway inflammation. On two different days, the patients inhaled hypertonic saline (3–5% NaCl) or isotonic saline (0.9% NaCl) for 30 min via an ultrasonic nebulizer, while monitoring FEV₁. Sputum was collected for inflammatory cell analysis. Results There was no difference in inflammatory cell percentages obtained with the two methods. Eosinophils were >1% in 20 subjects after hypertonic saline and in 16 subjects after isotonic saline, but this difference was not statistically significant. Intraclass correlation coefficients for sputum inflammatory cells obtained with the two methods were +0.642 for eosinophils, +0.644 for neutrophils. +0.544 for lymphocytes and +0.505 for macrophages. Hypertonic saline induced bronchoconstriction in a significantly greater number of subjects than isotonic saline. Also, hypertonic saline increased bronchial responsiveness to methacholine. while isotonic saline did not. Conclusion We conclude that hypertonicity does not affect sputum cell composition, suggesting that inflammatory cells in hypertonic saline-induced sputum are probably preexisting and not acutely recruited in the airways by the hypertonic stimulus. However, the bronchoconstriction and the increase in bronchial hyper-responsiveness after hypertonic saline inhalation may imply the release of inflammatory mediators. This fact must be considered in the evaluation of soluble markers of inflammation in hypertonic salineinduced sputum.