Airway neutrophil inflammation in nonasthmatic patients with food allergy

BACKGROUND: Patients with food allergy (FA) have been recently shown to develop bronchial hyperresponsiveness (BHR), despite the absence of any concomitant asthmatic manifestation. In order to explain this observation, we sought to examine the presence of a bronchial inflammation in induced sputum of nonasthmatic patients with FA. METHODS: Twelve nonasthmatic patients with FA (urticaria, digestive symptoms, anaphylaxis) were included in the study. Results were compared to these obtained from eight asthmatic patients without food allergy and eight healthy controls. Diagnosis of FA was based on double-blind placebo-controlled challenge. Sputum cells and fluid-phase eosinophil cationic protein (ECP), myeloperoxidase (MPO) and interleukin-8 (IL-8) were measured in induced sputum. BHR was evaluated using methacholine inhalation. RESULTS: Sputum from asthmatics, in comparison with the sputum of healthy subjects and patients with FA contained a higher proportion of eosinophils and higher levels of ECP (< 0.001). In marked contrast, patients with FA exhibited an increased proportion of neutrophils and IL-8 in comparison with asthmatics and controls (P < 0.05 for neutrophils and P < 0.001 for IL-8). There was a significant correlation between sputum neutrophils and IL-8 (r = 0.68, P < 0.001). MPO levels were not different between the groups. There was a trend toward higher levels of IL-8 and ECP in food allergic patients with BHR in comparison with patients with FA without BHR. CONCLUSION: Our results demonstrate that a subclinical neutrophil airway inflammation is present in patients with food allergy free of clinical respiratory symptoms and that IL-8 may be an important mediator of this neutrophilia.     

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.     

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.     

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.     

Allergen-induced bronchial inflammation in house dust mite-allergic patients with or without asthma

BACKGROUND: It is presently unknown which factors determine the occurrence and persistence of asthma in house dust mite-allergic individuals. The level of allergen-specific IgE antibodies does not seem to be decisive for asthmatic symptoms. Moreover, levels of exposure to mite allergens do not seem to differ significantly between asthmatic and non-asthmatics individuals. AIM: It was hypothesized that the presence or absence of asthmatic symptoms in house dust mite-allergic patients is associated with quantitative or qualitative differences in the cellular bronchial inflammatory response during the late phase of the allergic reaction. This hypothesis was tested in the bronchial allergen challenge model. MATERIAL AND METHODS: Whole lung challenges with house dust mite extract were performed in 52 house dust mite-allergic subjects, of whom 26 had asthma and 26 had perennial rhinitis without asthmatic symptoms. Primary outcomes were parameters for bronchial inflammation in serial samples of induced sputum (cell differentials, eosinophil cationic protein (ECP), interleukin-8 (IL-8), myeloperoxydase (MPO)). In addition, lung function, non-specific bronchial hyper-responsiveness and serial blood samples (eosinophils and IL-5) were analysed. RESULTS: At baseline sputum eosinophils and ECP were similar in both groups but neutrophils and IL-8 were higher in asthmatics. The early bronchoconstriction after allergen challenge was similar in asthma and non-asthmatic rhinitis (median decrease in FEV1: asthma -31.7% vs. non-asthmatics -29.1%, P > 0.1). The late phase bronchoconstriction was significantly greater in asthma (median decrease in FEV1: asthma -27.6% vs. non-asthmatics -18.9%, P = 0.02). Induction of bronchial hyper-responsiveness was similar in both groups. Bronchial allergen challenge elicited significant increases in sputum eosinophils and ECP, which were indistinguishable for both groups (P > 0.1 and P = 0.07, respectively). In contrast, higher numbers of neutrophils persisted in asthma 24h after challenge and were accompanied by significant increases in IL-8 and MPO, which were absent in non-asthmatics (difference between groups P = 0.007 and P = 0.05, respectively). CONCLUSION: Allergen challenge inducedvery similar increases in eosinophils and ECP in induced sputum in allergic asthmatics and in allergic non-asthmatic patients. The difference in bronchial inflammation between asthma and non-asthmatic rhinitis appeared to be more closely related to indices for neutrophilic inflammation.     

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.     

Corticosteroid resistance in mild asthma: markers of persistent inflammation.

BACKGROUND: Bronchial hyperresponsiveness (BHR) is an important feature of asthma. Glucocorticosteroids (GCS) reduce BHR, probably by suppressing allergic inflammation. There are, however, two groups of asthmatics with either GCS-responsive or non-responsive BHR to methacholine. We investigated the mechanism of non-GCS-responsive BHR in mild asthma. METHODS: Non-GCS-responsive BHR asthma was defined as failure of reduction of BHR to methacholine after a 2-week course of oral prednisolone (30 mg/day). The expression of interleukin (IL)-4, IL-5, IFN-gamma mRNA in peripheral blood mononuclear cells, eosinophil count, serum cortisol, eosinophilic cationic protein (ECP), and spirometry were measured in five non-GCS-responsive BHR asthmatics and six patients with GCS-responsive BHR asthma before and after prednisolone therapy. RESULTS: With the exception of serum ECP and expression of IL-5 mRNA, no significant differences were observed between GCS-responsive BHR and non-GCS-responsive BHR asthma. The mean ECP level was significantly higher in non-GCS-responsive BHR than in GCS-responsive BHR asthma before and after prednisolone therapy. Interleukin-5 mRNA was detected in all asthmatics before prednisolone therapy; however, after prednisolone therapy, IL-5 mRNA was only detected in non-GCS-responsive BHR asthmatics. CONCLUSIONS: Our findings suggest that activation of eosinophils appears to persist in some asthmatics with non-GCS-responsive BHR due to continuous IL-5 production by lymphocytes.     

Induced sputum to assess airway inflammation: a study of reproducibility

Background Infiltration of the airways mucosa with activated inflammatory cells appears to be a major factor in the pathogenesis of asthma and other airway diseases. Examination of sputum provides a direct method to investigate airway inflammation non-invasively. Objectives The aim of the present study was to evaluate the reproducibility of cell counts on cytospins and fluid phase (eosinophil cationic protein, ECP) measurements in a selected portion of induced sputum. We aimed to confirm the validity of the tecnique by comparing measurements between stable asthmatics, allergic rhinithis and healthy subjects. Methods Sputum was induced with hypertonic saline (4.5%) twice within one week in 53 stable asthmatics, 16 subjects with seasonal rhinitis (out of the pollen season), and 19 healthy subjects. Reproducibility was examined within sample (two different plugs of the same sample) between sample (two specimens of induced sputum obtained within one week) and between examiners on stable subjects taking into account sample size, number of examinations per patients and Confidence Interval (CI) of the estimates. Results We have found that the method is highly reproducible within sample and between examiners for all types of cells and fluid phase measurements of ECP. It is reproducible between sample for eosinophils, macrophages, neutrophils and ECP, but not for lymphocytes and weakly for epithelial cells. Sputum from asthmatics, in comparison with the sputum of healthy subjects and subjects with rhinitis had higher eosinophils (asthmatics: 12.2%± 12.9, rhinitis: 0.4 ± 0.8, normals: 0.4 ± 0.7(%) and ECP (asthmatics: 827 ± 491 μg/L, rhinitis: 127 ± 82 normals: 157 ± 203). No significant differences were found between healthy subjects and subjects with rhinitis. Eosinophil counts were inversely correlated with FEV₁ (r=?0.37) expressed as percentage of predicted, but not significantly correlated with PC₂₀ methacholine (r =?0.28) or blood eosinophils (r = 0.26). Conclusions The importance of this study is the confirmation, within important statistical guidelines for a study of reproducibility, that the methods examined are reproducible and valid.     

Diagnostic accuracy of sputum outcomes in chronic stable asthma

BACKGROUND: Asthma with non-remitting airflow obstruction may not always be differentiated from COPD with airway hyperreactivity. Many attempts have been made to find useful markers for the distinction between these two disorders. OBJECTIVE AND METHODS: In order to help the finding of a useful marker for the diagnosis of asthma in the population of patients with airway obstruction we analysed the diagnostic accuracy of sputum eosinophils and sputum ECP in 91 patients with asthma, 15 patients with chronic bronchitis, 32 patients with chronic obstructive pulmonary disease (COPD) and 20 controls subjects, by performing ROC analysis. RESULTS: Sputum eosinophils were above the normal range of our laboratory (0-3.7%) in 48 asthma patients and in six COPD patients, while sputum ECP (normal range < 85 microg/L) was high in 65 asthma patients, in 24 COPD patients and in nine chronic bronchitis patients. The ROC analysis revealed that sputum eosinophils count (AUC = 0.82) was more accurate than both sputum ECP levels (AUC = 0.56) (P < 0.0001) and beta2-reversibility (AUC = 0.53) (P = 0.0001) in differentiating asthmatic from non-asthmatic subjects (COPD, chronic bronchitis patients and normal subjects). The diagnostic accuracy of ECP was similar to that of bronchial reversibility (P = 0.76). When ROC analysis was performed by including only patients with airway obstruction (36 asthmatics with airway obstruction and COPD patients), both eosinophil count (AUC = 0.77) and beta2-reversibility (AUC = 0.66) were more accurate than ECP measurement (AUC = 0.39) in discriminating asthmatics from COPD patients (P < 0.00001 and P = 0.04, respectively). CONCLUSION: Sputum eosinophils seem to be valid markers for detecting asthma in a population of patients with airway obstruction. Moreover, the higher diagnostic accuracy of eosinophils in the sputum compared to sputum ECP and bronchial reversibility reinforces the role of cytological analysis of sputum in the diagnosis of chronic stable bronchial asthma.     

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.     

Macrophage migration inhibitory factor (MIF) in bronchial asthma

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine favouring the secretion of TNFalpha and IL-8 and counteracts anti-inflammatory effects of corticosteroids. Airways inflammation is a central feature of bronchial asthma and is characterized by the accumulation of eosinophils. OBJECTIVE: The aim of this study was to investigate whether MIF is related to asthma symptoms and eosinophil accumulation in the airways. METHODS: Serum MIF levels were measured by an enzyme-linked immunosorbent assay in 44 healthy subjects and 44 asthmatics. Levels of MIF in induced sputum were measured in 10 healthy subjects and 15 asthmatics. Levels of eosinophil cationic protein (ECP) in induced sputum were measured by a radioimmunosorbent assay. Fluorescence double immunostaining was conducted to examine cellular source and localization of MIF. RESULTS: Serum MIF levels were significantly increased in asthmatic patients compared with age and sex-matched control subjects. Symptomatic patients had a higher MIF level than asymptomatic patients. Induced sputum obtained from asthmatics contained higher levels of MIF than those from control subjects. MIF levels in induced sputum were correlated with ECP levels in induced sputum. MIF was colocalized with eosinophil peroxidase staining in the cytoplasm of sputum cells. CONCLUSION: Increased MIF levels are associated with asthma symptoms and one of the cellular sources of MIF in the airways are eosinophils.     

Effect of nasal triamcinolone acetonide on seasonal variations of bronchial hyperresponsiveness and bronchial inflammation in nonasthmatic children with seasonal allergic rhinitis.

BACKGROUND: Recent evidence suggests that patients with allergic rhinitis have lower airway inflammation and a higher prevalence of bronchial hyperresponsiveness (BHR) regardless of asthma. OBJECTIVE: To investigate markers of lower airway inflammation in nonasthmatic children with seasonal allergic rhinitis (SAR) before and during pollen season and the effect of nasal triamcinolone acetonide on seasonal variations in these parameters. METHODS: Thirty-two nonasthmatic children with SAR in response to grass and/or weed pollens were recruited and separated into 2 groups. Group 1 was treated with triamcinolone acetonide (220 microg once daily) for 6 weeks, and group 2 received no intranasal corticosteroid treatment. Bronchial responsiveness to methacholine [concentration that caused a decrease in forced expiratory volume in 1 second of 20% (PC20)], eosinophil counts in sputum and peripheral blood, and eosinophil cationic protein (ECP) levels in sputum and serum were measured before and during grass pollen season. RESULTS: Twenty-eight patients completed the study. During the pollen season, methacholine PC20 significantly decreased in both groups when compared with the corresponding preseasonal values (P = .01 and P = .003, respectively). The mean percentage of sputum eosinophils increased significantly during the pollen season compared with preseasonal values in group 1 and group 2 (12.7% +/- 2.1% vs 16.5% +/- 2.1%, P = .007, and 11.0% +/- 2.0% vs 20.2% +/- 1.4%, P = .003, respectively). Median [interquartile ranges (IQR)] sputum ECP levels were significantly higher during the pollen season when compared with the preseasonal values in group 1 and group 2 [7.5 microg/L (3.5-36.0 microg/L) vs 35.5 microg/L (13.0-71.7 microg/L), P = .04, and 18.0 microg/L (6.0-36.0 microg/L) vs 69.0 microg/L (39.0-195.0 microg/L), P = .003, respectively], as were the serum ECP levels [6.0 microg/L (2.0-13.0 microg/L) vs 19.0 microg/L (14.0-43.5 microg/L), P = .004, and 6.0 microg/L (3.0-7.0 microg/L) vs 18.0 microg/L (6.0-36.0 microg/L), P = .001, respectively]. Although the mean number of eosinophils in blood increased during the pollen season in both groups, it was only significant in group 2 (70.0 +/- 20.0 vs 161.6 +/- 29.0, P = .02). CONCLUSIONS: Although prophylactic nasal corticosteroid treatment provides significant reduction of nasal symptoms and rescue antihistamine use, there is no significant prevention in the seasonal increase of bronchial inflammation and methacholine BHR.     

Dissimilarity between seasonal changes in airway responsiveness to adenosine-5'-monophosphate and methacholine in patients with grass pollen allergic rhinitis: relation to induced sputum

BACKGROUND: In patients with allergic rhinitis, bronchial hyperresponsiveness (BHR) and airway inflammation may increase during pollen exposure. BHR can be assessed by adenosine-5'-monophosphate (AMP) or methacholine challenge. It has been suggested that BHR to AMP is more closely related to airway inflammation than BHR to methacholine. Seasonal allergic rhinitis offers a dynamic model to study changes in BHR and airway inflammation during natural allergen exposure. METHODS: We measured BHR [provocative concentration causing a 20% fall (PC(20)) in forced expiratory volume in 1 s (FEV(1))] to AMP and methacholine, and induced sputum cells in 16 rhinitis patients before and during the 2001 grass pollen season. RESULTS: There was a decrease in PC(20) methacholine during pollen exposure (geometric mean PC(20) from 3.22 to 1.73 mg/ml, p = 0.0023), whereas no reduction was observed for PC(20) AMP (p = 0.11). There was no increase in sputum eosinophils [pre: 0.69% (95% confidence interval 0.22-2.07); during: 1.85 (0.55- 5.6), p = 0.31]. Although the correlation of log PC(20) methacholine and log PC(20) AMP at baseline was good (r = 0.76, p = 0.001), individual seasonal changes (doubling concentrations) in PC(20) methacholine were not correlated with changes in PC(20) AMP (rho = 0.21, p = 0.44). There was no correlation between baseline log PC(20) methacholine or seasonal changes in PC(20) methacholine and sputum eosinophils (p > 0.12, all correlations). In contrast, there was a significant correlation between seasonal changes in PC(20) AMP and changes in sputum eosinophils (rho = -0.59, p = 0.025). CONCLUSIONS: These data show dissimilarity between seasonal changes in PC(20) AMP and methacholine in patients with seasonal allergic rhinitis. Moreover, PC(20) AMP seems to be more closely related to sputum eosinophils than PC(20) methacholine. The clinical significance of this discrepancy is unclear.     

Nitric oxide metabolites,eosinophils, and eosinophilic cationic protein in patients with asthma: sputum versus blood

The monitoring of airway inflammation has assessed in bronchial asthma directly by sputum examination, and indirectly by measurements in peripheral blood. To investigate the diagnostic value of these two methods, we compared nitric oxide (NO) metabolites, eosinophils, and eosinophil cationic protein (ECP) in sputum and blood in patients with asthma and control subjects. Sputum and serum were obtained from fifteen patients with asthma, and then were examined before anti-asthma treatment, including steroid preparations. ECP was measured by fluoroimmunoassay. NO metabolites were assayed by using modified Griess reaction. Asthmatic patients, compared with control subjects, had significantly higher level of NO metabolites, higher proportion of eosinophils, and higher levels of ECP in sputum. Asthmatic patients, compared with control subjects, however, had significantly higher number of eosinophils, and were at higher levels of ECP in blood. FEV1, FEV1/FVC was negatively correlated with sputum eosinophils. The area under receiver operating characteristic (ROC) curve showed that eosinophils in sputum are significantly accurate markers than NO metabolites in sputum and blood. These findings suggest that the proportion of eosinophils in sputum have more accurate diagnostic marker of asthmatic airway inflammation than NO metabolites in sputum in differentiating asthmatic patients from control subjects.     

Airway mast-cell activation in asthmatics is associated with selective sputum eosinophilia

BACKGROUND: Tryptase is a serine endoprotease selectively released from mast cells. Although mast cells are known to be activated after experimental allergic provocation, their role in naturally occurring asthma is still debated. METHODS: We have investigated the levels of tryptase in the whole induced sputum collected from 51 asthmatics (31 atopic and 20 intrinsic) seen in our outpatient clinic and 22 normal nonatopic healthy volunteers. Tryptase was measured by a new immunoassay based on B12 monoclonal antibody recognition of total tryptase (UniCAP System, Pharmacia) with a sensitivity of 1 ng/ml. RESULTS: While being below the threshold of detection in all normal volunteers, tryptase was detectable in the sputum from 9/51 asthmatics (18%) including five atopic and four intrinsic asthma cases. In these patients, among whom three were asymptomatic asthmatics, the values ranged between 1 and 6.1 ng/ml. The asthmatics with detectable sputum tryptase had greater sputum eosinophil counts (P<0.05) but lower neutrophil counts (P<0.05) than those in whom tryptase was undetectable. When compared to control subjects, asthmatics without tryptase had still greater eosinophil counts (P<0.0001) but also raised neutrophil counts (P<0.05). No significant difference could be found between asthmatics with tryptase and those without tryptase with respect to the age, the baseline lung function, the methacholine bronchial responsiveness, and the frequency of treatment with inhaled steroids. CONCLUSIONS: With the UniCAP System, tryptase was detectable in the sputum from 18% of asthmatics irrespective of atopy and current symptoms. Asthmatics with tryptase appeared to have a selective increase in sputum eosinophil counts while those without tryptase displayed a mixed sputum granulocyte infiltration with raised eosinophil and neutrophil counts.     

哮喘患者血浆类胰蛋白酶、血嗜酸粒细胞和气道高反应性相互关系

为探讨肥大细胞、嗜酸粒细胞和气道高反应性相互关系 ,本文检测了 36例哮喘患者 (哮喘组 )及 2 9例健康人 (对照组 )血浆中激活肥大细胞的特征性标志物类胰蛋白酶值、血嗜酸粒细胞 (EOS )值及乙酰甲胆碱的支气管激发试验 (PC2 0 )值 ,并对三者关系进行分析比较 ,结果 :(1)哮喘组血浆类胰蛋白酶增高率为 36 11% (13/ 36)和EOS增高率为 38 89% (14/ 36 ) ,明显高于对照组 (P分别 <0 0 0 5 ) ;(2 )哮喘组PC2 0 值 <8g/L者占 81 82 % (2 7/ 33) ,显著低于对照组 (P <0 0 0 5 ) ;(3)哮喘EOS增高组的PC2 0 值为 1 2 1g/L ,明显低于EOS正常组的 5 11g/L (P <0 0 1) ;(4 )哮喘类胰蛋白酶增高组中有 61 5 3% (8/13)EOS值增高 ,明显高于类胰蛋白酶正常组的 2 6 0 9% (6/ 2 3) (P <0 0 5 )。综上所述 ,哮喘患者呈气道高反应 ,血EOS和类胰蛋白酶值增高 ;EOS与气道高反应性有关 ;类胰蛋白酶与EOS增高有关 ,但未直接与气道高反应性相关     

Sputum eosinophil counts and eosinophil cationic protein levels in cough-variant asthma and in classic asthma, and their relationships to airway hypersensitivity or maximal airway response to methacholine

Background:  The aims of this study were to compare the degree of airway inflammation in cough-variant asthma (CVA) with that in classic asthma (CA), and to examine the relationship between airway inflammation and airway hypersensitivity or maximal airway response to methacholine in both conditions.
Methods:  Sputum was induced in 41 CVA patients, in 41 methacholine PC₂₀-matched CA patients, and in 20 healthy children. The sputum samples were analyzed for total and differential cell counts, and for eosinophilic cationic protein (ECP). A high-dose methacholine challenge test was performed in CVA and CA patients to determine PC₂₀ and maximal airway response.
Results:  Sputum eosinophil percentages and ECP levels were significantly elevated in CVA and CA vs the control, but no significant differences were found between the two asthma groups. In the two asthma groups, neither sputum parameters correlated significantly with methacholine PC₂₀. However, the absence of a maximal response plateau or its higher level, when present, was associated with increased eosinophil percentages and ECP levels in the CVA group.
Conclusions:  The degree of eosinophilic inflammation may not be causally related to differences in presented asthma manifestations. The identification of a maximal response plateau and the level of this plateau in patients with CVA may provide information pertinent to airway eosinophilic inflammation.     

Effects of prednisolone on eosinophils, IL-5, eosinophil cationic protein, EG2+ eosinophils, and nitric oxide metabolites in the sputum of patients with exacerbated asthma

Corticosteroids are considered to be one of the most effective medicine for asthma by suppressing airway inflammation. This study was carried out to investigate the effects of prednisolone in the sputum of exacerbated asthmatics. Clinical severity, cell differentials, levels of interleukin (IL)-5, eosinophil cationic protein (ECP), EG2+ eosinophils, and nitric oxide (NO) metabolites were measured. Sputum was examined 2 weeks apart in 13 exacerbated asthmatics before and after prednisolone treatment, and once in 12 stable asthmatics. We used a sandwich ELISA for IL-5, fluoroimmunoassay for ECP, immunohistochemical staining for EG2+ eosinophils, a NO metabolites assay using modified Griess reaction. Exacerbated asthmatics, in comparison with stable asthmatics, had significantly higher proportion of eosinophils, higher level of ECP, higher percentage of EG2+ eosinophils, and NO metabolites. Exacerbated asthmatics after treatment with prednisolone had reduced the proportions of eosinophils, reduced level of IL-5, ECP and percentage of EG2+ eosinophils. FEV1 was correlated with the proportion of eosinophils, ECP, and IL-5 respectively. These findings suggest that prednisolone is considered to be effective medicine for asthma by suppressing eosinophil activation through IL-5.     

Asthma, bronchial hyperreactivity and mediator release in children with birch pollinosis. ECP and EPX levels are not related to bronchial hyperreactivity

Background Symptoms of allergic asthma are triggered by allergen exposure inducing allergic inflammation and hyperreactivity of the bronchi. Objectives To investigate the possible relationship between clinical symptoms and signs of asthma, i.e. bronchial variability as measured by peak expiatory flow rate (PEFR). bronchial hyperreactivity (BHR) and mediators of allergic inflammation. Methods Twenty-eight children with pollinosis. but no obvious history of asthma, were studied at three occasions, i.e. before, during and after (autumn) the birch pollen season. Twelve children sensitive to birch pollen were considered as the case group. Sixteen children, who were only clinically sensitive to grass pollen, served as controls. Subjective symptoms of asthma were recorded by visual analogue scale, BHR was estimated by methacholine bronchial provocation tests, bronchial variability PEFR and circulating mediators of inflammation, i.e. eosinophil cationic protein, eosinophil protein X, myeloperoxidase and tryptase in serum. Results Bronchial hyperreactivity and by PEFR was more pronounced after than during the season (P < 0.01), whereas eosinophil mediators and the peak expiratory flow rate increased during the season (P < 0.05). Except for between PEFR variability and BHR in the autumn (r= 0.45; P= 0.014). no correlations were found. However, in the autumn, the majority of children were still hyperreactive in the bronchi and showed PEFR variability but the levels of eosinophil mediators in serum had returned to normal levels. Conclusion Signs and symptoms of asthma did not correlate with serum levels of mediators of allergic inflammation. Bronchial hyperreactivity and PEFR variability persisted after the pollen season when signs of bronchial inflammation had disappeared. We hypothesize that eosinophil mediators and other markers of allergic inflammation disappear after the late-phase reaction, whereas BHR persists. This would explain the lack of correlation between the levels of eosinophil mediators in serum and symptoms of asthma and BHR.     

Eosinophilic airway inflammation in nasal polyposis.

BACKGROUND: Asthma and asymptomatic bronchial hyperresponsiveness (BHR) are frequent findings in patients with nasal polyposis (NP). OBJECTIVE: To elucidate mechanisms responsible for the development of BHR, we initiated a prospective study of bronchial inflammation as assessed by bronchial lavage (BL) and bronchial biopsy specimens in 35 patients with noninfectious NP. METHODS: BHR was determined with methacholine provocation testing. Differential cell count, ECP, and histamine and tryptase levels were determined in BLs. Pathologic examination of bronchial biopsy specimens was performed with May-Grünwald-Giemsa stain to assess the number of lymphocytes. Indirect immunoenzymatic methods were used to identify eosinophils and mast cells. RESULTS: Fourteen patients did not exhibit BHR (group A); 7 patients had asymptomatic BHR (group B); and 14 patients had BHR associated with asthma (group C). Patients of group C tended to have a longer duration of nasal symptoms than those of groups A and B. FEV1 (L) was significantly lower in group C than in groups A and B. The number and percentage of eosinophils were significantly higher in BLs in groups B and C than in group A (P <. 05). Patients of groups B and C had a significantly higher number of eosinophils in bronchial submucosa (14.0 +/- 1.5/mm2 and 19.0 +/- 1. 9/mm2, respectively) than patients of group A (0.1 +/- 0.1/mm2). The number of lymphocytes was also higher in groups B and C than in group A. FEV1 (percent of predicted value) and eosinophil number within bronchial mucosa correlated negatively. CONCLUSION: Our results demonstrate that patients with NP and asymptomatic BHR had an eosinophilic bronchial inflammation similar to that observed in asthmatic patients with NP, whereas patients with NP without BHR do not feature eosinophilic lower airways inflammation. The clinical relevance of these results requires careful follow-up to determine whether eosinophilic inflammation in these patients precedes and is responsible for the development of obvious asthma.