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.     

Changes in sputum cell counts after exposure to occupational agents: what do they mean?

BACKGROUND: Exposure to occupational agents can induce eosinophilic inflammation in subjects with occupational asthma (OA). It might also induce nonspecific changes in airway inflammation in subjects without OA. OBJECTIVES: We sought to investigate the changes in airway inflammation induced by exposure to occupational agents in subjects with and without OA and to determine which changes in sputum eosinophil numbers and bronchial responsiveness to methacholine should be regarded as clinically significant for predicting a 20% fall in FEV(1). METHODS: We performed specific inhalation challenges (SICs) in 3 groups of subjects: subjects reporting a history consistent with OA with a positive SIC response (n = 17); subjects reporting a history consistent with OA with a negative SIC response (n = 14); and asthmatic subjects without any history of OA (n = 10). Induced sputum and methacholine challenges were performed at the end of the control day and again at the end of the last day of exposure; the last day of exposure was always performed in the laboratory. RESULTS: There was an increase in median sputum eosinophil and neutrophil numbers in subjects with positive SIC responses. Cell counts remained unchanged after exposure in asthmatic subjects without OA. A combination of a greater than 0.26 10(6)/mL increase in sputum eosinophil numbers and a decrease in the concentration of methacholine inducing a 20% fall in FEV(1) of at least 1.8-fold compared with baseline values predicted a 20% fall in FEV(1) in 96% (95% CI, 70%-99%) of patients. CONCLUSION: Exposure to occupational agents per se does not induce airway inflammation. Changes in both sputum eosinophil counts and methacholine responsiveness are satisfactory predictors of a significant bronchial responsiveness to occupational agents.     

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.     

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.     

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.     

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.     

Oilseed rape flour: another allergen causing occupational asthma among farmers

BACKGROUND: Farmers are exposed to a wide variety of sensitizers. Since occupational asthma (OA) can lead to permanent disability, exposure discontinuation is the preferred treatment. When this is not possible, the identification of the causative allergen may allow an alternative therapy. METHODS: We present three farmers diagnosed with OA as a consequence of handling fodder. We carried out skin tests with common and occupational allergens and with oilseed rape (OSR) extract. Total and specific serum IgE levels were measured. The patients underwent the OSR-bronchial provocation test (OSR-BPT). The day before and 24 h after the OSR-BPT, the methacholine (M)-BPT and induced sputum were performed. Eosinophil percentages and ECP levels were measured in the sputum samples. RESULTS: OSR sensitization (skin tests and specific serum IgE) was detected in all the patients. The OSR-BPT elicited early responses in two subjects. Methacholine sensitivity, sputum eosinophils, and sputum ECP levels increased 24 h after the OSR-BPT in all the patients. CONCLUSIONS: We have demonstrated that inhalation of OSR flour causes bronchoconstriction, induces an eosinophilic inflammatory bronchial response, and increases bronchial hyperresponsiveness in sensitized asthmatics. OSR flour contained in animal fodder should be considered another potential cause of OA among farmers.     

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.     

Liposome-entrapped D. pteronyssinus vaccination in mild asthma patients: effect of 1-year double-blind, placebo-controlled trial on inflammation, bronchial hyper-responsiveness and immediate and late bronchial responses to the allergen

BACKGROUND: Allergen vaccination is effective in mite-allergic asthma. Liposomes are immunological adjuvants that can act as allergen carriers. OBJECTIVE: To evaluate the immunological and functional effects of a liposome-entrapped D. pteronyssinus vaccine on mite monosensitive, mild asthma patients. METHODS: A double-blind, placebo-controlled trial was conducted on 26 asthma patients who randomly received vaccination or placebo for 1 year. The levels of exposure to Der p 1 allergen were constant during the study. Allergen bronchial challenge was made at the beginning (T0) and after 1 year of treatment (T12). The day before and 24 h after the allergen provocation, patients were challenged with methacholine (Mth) (until FEV1 fell by 40%) and blood and sputum samples were obtained. Dose-response curves to Mth were evaluated in terms of Mth-PD20 (dose of Mth that induced 20% drop in FEV1), slope (Mth-DRS) and level of plateau. Blood and sputum eosinophils and serum levels of eosinophil cationic protein (ECP) and intercellular adhesion molecule-1 (ICAM-1) were measured. RESULTS: Groups were comparable at the start of the trial. At TI2, previous to the allergen challenge, the active group showed higher values of both FEV1 and Mth-PD20 and lower values of Mth-DRS. The number of patients presenting a level of plateau increased in the active group (from two to four) and decreased in the placebo group (from two to one). At T12, before the allergen challenge, serum ECP levels increased in the placebo group and blood eosinophils showed a trend towards lower numbers in the active one. The immediate response and the changes in Mth-DRS values, sputum eosinophils and serum ECP levels following the allergen challenge were attenuated in the active group. CONCLUSION: Liposome-entrapped D. Pteronyssinus vaccination: (i) protects mild asthma patients from the worsening of asthma due to sustained mite exposure; and (ii) reduces the functional and inflammatory changes induced by allergen bronchial provocation.     

Repeated inhalation of low doses of cat allergen that do not induce clinical symptoms increases bronchial hyperresponsiveness and eosinophil cationic protein levels.

The aim of this study was to investigate whether repeated exposure to subclinical doses of cat allergens, not inducing asthma symptoms, could affect eosinophil cationic protein (ECP) levels in bronchoalveolar lavage (BAL) or in peripheral blood, without the appearance of clinical symptoms. Twelve patients with mild asthma, all sensitized to cats and not exposed to cat allergen at home, underwent a series of inhalations of cat allergen or placebo for 8 days over 2 weeks. A methacholine challenge was performed before and after the allergen and saline exposures, and BAL and blood were sampled for ECP measurements and eosinophil counts. No patients experienced asthma symptoms. However, PD20 methacholine (geometric mean) decreased significantly from 263 microg before to 126 microg after inhalation of allergen. Inhalation of saline did not induce any significant change in PD20. The change in log PD20 before and after cat allergen exposure was statistically different from the change in log PD20 before and after saline. Median ECP levels in BAL and serum increased significantly after allergen exposure, from 0.8 to 3.1 microg/l (p<0.02) and from 15.9 to 31.4 microg/l (p<0.05), respectively. No change was observed after saline inhalations. The change in BAL and serum ECP levels was statistically significant compared to that in the control group. The number of eosinophils did not change, however, nor did IL-5 and RANTES levels in BAL and serum. In conclusion, our results show that (1) exposure of asthma patients to repeated low doses of allergen, which did not provoke any clinical symptoms, is capable of inducing a local eosinophil activation associated with an increase in nonspecific bronchial hyperresponsiveness and (2) the increase in serum ECP levels due to eosinophil activation precedes the occurrence of asthma symptoms and may thus be a marker of allergen exposure in allergic asthma.     

Analysis of induced sputum to examine the effects of inhaled corticosteroid on airway inflammation in children with asthma.

BACKGROUND: Analysis of induced sputum can be performed safely in children with asthma and is useful for both cellular and biochemical markers of inflammation. Glucocorticosteroid inhalation has become the first line therapy for chronic asthma by suppressing airway inflammation, which produces the decrease of bronchial hyperreactivity and reduces the number of eosinophil in bronchial submucosa. OBJECTIVE: To determine the characteristics of the inflammatory cells and their markers in sputum and to examine the pharmacokinetic effects of glucocorticoid within 3 hours after inhalation therapy on FEV1 and sputum inflammatory indices in children with clinically defined chronic asthma. METHODS: Thirty subjects with asthma included 14 current symptomatic asthmatics and 14 normal controls inhaled 4.5% hypertonic saline for 10 minutes by nebulizer. The expectorated sputum were collected from all asthmatics before and 3 hours after corticosteroid inhalation for children with asthma and were reduced by dithiotreitol. Total cell counts and differentials were determined. ECP was measured by CAP system. Interleukin-5, GM-CSF and albumin were measured by double sandwich ELISA. RESULTS: The mean eosinophil percentage and ECP in induced sputum of asthmatics were significantly higher than that of controls. The induced sputum samples obtained after glucocorticoid inhalation showed a significant reduction in mean eosinophil percentage, but FEV1, IL-5, GM-CSF, albumin, and ECP values were not significantly decreased. CONCLUSION: The present results in induced sputum may be interpreted to reflect direct steroid action on airways and lack of effect on bone marrow effectors at 3 hours after glucocorticoid inhalation.     

Influence of total IgE and seasonal increase of eosinophil cationic protein on bronchial hyperreactivity in asthmatic grass-sensitized farmers

BACKGROUND: This study correlates biomarkers of atopy (serum total and specific IgE) and inflammation (serum eosinophil cationic protein) with bronchial hyperreactivity assessed after the complete end of pollination, in a group of farmers suffering from grass-allergic asthma. METHODS: A total of 28 asthmatic farmers, with allergy to grass pollen, reporting persistent asthma symptoms after grass pollination, were enrolled. An accurate allergologic screening excluded other sensitizations. Analysis of total and grass-specific IgE and eosinophil cationic protein was carried out before (March) and during (May) the following spring. After the complete end of pollination, bronchial hyperreactivity was assessed. RESULTS: Symptoms (cough, wheezing) persisted during the autumn for a mean period of 41 days (range 13-69). Total IgE was moderately high and grass-specific IgE ranged from 9.25 to 41.12 kU/l without significant differences before and during spring. On the contrary, serum ECP levels significantly increased during the pollination period. PD20 methacholine evaluated after the end of grass pollination was negatively significantly correlated with levels of total IgE (r=-0.73; P<0.01) and the increase (from March to May) of serum ECP (r=-0.75; P<0.01). However, PD20 methacholine did not correlate with grass-specific IgE and serum ECP absolute values of both March and May. A positive correlation was found between number of postseasonal days with symptoms and both spring increase of serum ECP (r=0.75; P=0.04) and levels of total IgE (r=0.76; P<0.01). The number of postseasonal days with symptoms inversely correlated with postseason PD20 methacholine (r=-0.76; P<0.01). CONCLUSIONS: The study demonstrates that in grass-sensitized farmers with asthmatic symptoms persisting for several weeks after grass pollination has ceased, the degree of airways hyperreactivity and the duration of postseasonal symptoms are directly related to the spring increase of ECP levels, as well as to the level of total IgE in serum. This allows us to identify two candidate biomarkers for the risk of developing prolonged asthma symptoms, and for the effective monitoring of anti-inflammatory treatment and allergen-specific immunotherapy.     

Low-dose endotoxin in allergic asthmatics: effect on bronchial and inflammatory response to cat allergen

BACKGROUND: Endotoxin was proposed to increase the severity of asthma. Endotoxin levels greatly differ according to settings. In domestic environments, airborne concentrations may be dramatically low compared with levels reported in occupational settings. OBJECTIVE: Our first objective was therefore to assess the effect of inhalation of low-level lipopolysaccharide (LPS) on the immediate and late-phase asthmatic bronchial response. Our second objective was to evaluate the effect of exposure to LPS on the local and systemic inflammatory response. METHODS: Nineteen asthmatics sensitized to cat underwent on two separate occasions a bronchial challenge test to cat allergen (cat BCT) preceded randomly by a pre-exposure to either saline or LPS (2 microg). Methacholine challenge test was performed 24 h before exposure to LPS or saline. The Borg scale for dyspnoea and lung function were recorded before and after exposure to LPS or saline, and before and after cat BCT. Induced sputum and blood samples were collected before and after cat BCT, and analysed for cell counts and eosinophil cationic protein (ECP) levels. RESULTS: Inhalation of 2 microg LPS did not induce any changes in forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), FEF 25-75 and Borg scale of dyspnoea. It neither modified Fel d 1 PD20 (45.03 ng as compared with 87.03; P=0.42). As well, there was no significant difference in late-phase reaction. Pre-exposure to LPS did not influence eosinophil counts or ECP levels in blood and sputum. CONCLUSION: Our study demonstrated that pre-exposure to LPS at low levels, which may be encountered in domestic environment, had no significant effect on the immediate and late-phase bronchial response to cat allergen. It neither modified local and systemic eosinophilic inflammation.     

Bronchial eosinophilic infiltration in Crohn's disease in the absence of pulmonary disease

BACKGROUND: Immunological and functional bronchopulmonary abnormalities may be present in up to two-thirds of patients with Crohn's disease. Having recently described a mild increase in methacholine airways responsiveness in these patients, we investigated whether this physiological abnormality is associated with bronchial inflammation since it has previously been described in asthma. METHODS: Eighteen patients with Crohn's disease and 15 healthy controls matched for age, atopy and smoking habit, were studied. All the subjects underwent a bronchial methacholine challenge (1, 4 and 16 mg/mL) and a sputum induction by inhalation of hypertonic saline (NaCl 4.5%). The sputum samples were analysed for their cellular composition as well as for the levels of several mediators and proteins in the fluid phase, including eosinophil cationic protein (ECP), myeloperoxydase, albumin, alpha2-macroglobulin, interleukin-8 (IL-8), IgA and IL-8/immunoglobulin A complexes. RESULTS: When compared to control subjects, patients with Crohn's disease had significantly higher sputum eosinophil counts (14.5% [0-79.9%] vs 0.2% [0-2.3%]; P < 0. 001) and ECP levels (26.2 microg/L [4-124.2 microg/L] vs 9.8 microg/L [0-94.2 microg/L]; P < 0.05). However, patients with Crohn's disease had no sign of increased plasma exudation as reflected by sputum levels of albumin and alpha2-macroglobulin similar to those seen in control subjects. Furthermore the sputum levels of IL-8, IgA and IL-8/IgA complexes were not significantly different between the two groups. The magnitude of the fall in forced expiratory volume in 1 s after methacholine inhalation was significantly increased in Crohn's disease patients although it did not correlate with the extent of sputum eosinophilia or with the sputum ECP levels. CONCLUSIONS: Crohn's disease patients without any clinical respiratory involvement have airway eosinophilia without local increased plasma exudation. However, bronchial eosinophilia in Crohn's disease per se is not sufficient to induce clinically significant airway hyperresponsiveness, suggesting that other factors than bronchial eosinophilic infiltration are required for the clinical expression of an airway instability.     

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.     

Clarithromycin suppresses bronchial hyperresponsiveness associated with eosinophilic inflammation in patients with asthma.

BACKGROUND: Although long-term administration of 14-membered macrolide antibiotics is a therapeutic alternative in asthma, both its pharmacologic mechanism of action and association with the pathogenesis of asthma remain obscure. OBJECTIVE: This study investigated the suppressive effect of clarithromycin on airway responsiveness to methacholine provocation testing and examined whether chrarithromycin's antiasthmatic activity is associated with a reduction in eosinophilic inflammation. METHODS: For 8 weeks, patients received 200 mg of clarithromycin or identical-appearing placebo twice daily. We assessed the effects of treatment with clarithromycin on bronchoconstriction precipitated by inhalation of methacholine in 17 adults with mild or moderate bronchial asthma who were in stable clinical condition. A double-blind, randomized, crossover design was used. Eosinophil counts and eosinophilic cationic protein (ECP) levels were determined in blood and sputum samples obtained on the morning of the methacholine provocation testing day. RESULTS: After 8 weeks of treatment with clarithromycin, patients' symptoms, blood and sputum eosinophils counts and sputum ECP levels were significantly decreased compared with both placebo and baseline. Furthermore, values of PC20 methacholine improved in all patients after clarithromycin treatment. CONCLUSIONS: Clarithromycin has a bronchial anti-inflammatory effect associated with decreased eosinophilic infiltration. This study suggests interesting therapeutic possibilities for bronchial asthma that warrant further trials.     

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.     

Eosinophils and eosinophilic cationic protein in induced sputum and blood: effects of budesonide and terbutaline treatment.

BACKGROUND: There is a need for easily measurable markers of airway inflammation to guide the use of anti-inflammatory treatment in asthma. Eosinophilic cationic protein (ECP) levels in sputum and blood correlate with clinical severity, and serial measurements of ECP have been proposed as a suitable candidate. AIMS AND METHODS: Our aim was to confirm that sputum and serum ECP measurements would provide a more sensitive indicator of responses to asthma treatment than eosinophil counts per se, in a randomized, placebo-controlled, crossover study of terbutaline, budesonide, and their combination in patients with chronic persistent asthma. We compared the changes in eosinophil counts and ECP in induced sputum and blood during each treatment period. RESULTS: Budesonide and combined treatment caused a significant reduction in sputum eosinophils (-2.7% and -2.3%, respectively, P < 0.05). Sputum eosinophils increased with terbutaline (+3.9%, P = 0.049). In contrast, the changes for sputum ECP were not significant. There was a similar treatment effect on blood eosinophils, but not for serum ECP. Correlations between sputum and blood eosinophils were significant with and without budesonide, but were nonsignificant between sputum and blood ECP during the active treatments. Correlations between sputum eosinophils and ECP, and between blood eosinophils and serum ECP were greatest during treatment with placebo or terbutaline alone: budesonide weakened or abolished these relationships. CONCLUSIONS: Compared with eosinophil counts, ECP measurements in either induced sputum or serum failed to reflect treatment-related changes in chronic asthma. We conclude that ECP is not a sensitive or reliable means of evaluating airway inflammation, and can not be recommended for assessing responses to anti-inflammatory therapy.     

Sensitivity of sputum eosinophil cationic protein level for monitoring asthmatic patients with normal peak expiratory flow]

Previous studies have shown that eosinophils and eosinophil cationic protein (ECP) levels in the sputum of patients with asthma closely reflect inflammatory activity of the bronchial mucosa. We examined whether the ECP level or eosinophil count in induced sputum provides information useful in determining whether to taper the dose of medications or to terminate treatment especially with inhaled corticosteroids in patients with well controlled asthma. We studied 15 adults with asthma who consistently maintained a peak expiratory flow (PEF) value within 80% or more of their predicted value (green zone) for at least 4 weeks with no asthmatic symptoms. All patients underwent at least two hypretonic saline inhalation tests. Forty sputum samples were obtained for evaluation of cell count and ECP level. Before the tests, patients were requested to record asthmatic symptoms, medications received, and morning and evening PEF values in a diary for more than 3 months. The relations among clinical and laboratory variables, including symptoms scores, medication scores, asthma scores (= symptom scores + medication scores). PEF values, forced expiratory volume (FEV1.0) during the test, and sputum eosinophil count or sputum ECP, were analyzed. The sputum ECP level correlated significantly with the percentage of eosinophils in the sputum (rs = 0.783). There were also significant correlations between the sputum ECP level and the mean weekly symptom scores (rs = 0.500-0.510), medication scores (rs = 0.510-0.540), and asthma scores (rs = 0.509-0.548). However, there were no significant correlations among sputum ECP level, mean morning PEF or evening PEF, daily variation in PEF, and FEV1.0. We conclude that the sputum ECP level is a sensitive laboratory variable useful in monitoring the presence of eosinophilic inflammation in the bronchial mucosa of patients with bronchial asthma, especially those who have mild or no symptoms with normal PEF.     

Neutrophil activation following TDI bronchial challenges to the airway secretion from subjects with TDI-induced asthma

BACKGROUND: The immunopathological mechanism for occupational asthma induced by toluene diisocyanate (TDI) remains to be further clarified. There have been few reports suggesting involvement of neutrophils in inducing bronchoconstriction after TDI inhalation. OBJECTIVES: To further understand the role of neutrophils in the pathogenesis of TDI-induced asthma. MATERIALS AND METHODS: Eight TDI-induced asthmatic subjects were classified as group I, and five exposed workers who had complained of work-related symptoms and worked in the same workplace, but showed negative bronchial challenges were enrolled as controls (group II). Serum neutrophil chemotactic activity during TDI bronchial challenge test was measured by the Boyden chamber method. Induced sputum was collected before and after the TDI bronchial challenge test. The myeloperoxidase (MPO) and interleukin (IL) -8 levels in the sputum were measured using RIA and ELISA. RESULT: Serum neutrophil chemotactic activity significantly increased at 10 min (P = 0.01), then decreased at 60 min (P = 0.02) and remained unchanged for up to 420 min (P = 0.07) in group I subjects, while no significant changes were found in group II subjects (P > 0.05). MPO and IL-8 were abundantly present in the sputum of all the TDI-induced asthmatic subjects and they increased significantly at 420 min after the bronchial challenges (P = 0.02, P = 0.03, respectively), while no significant changes were noted in group II subjects (P > 0.05). CONCLUSION: These findings support the view that activated neutrophils may contribute to bronchoconstriction induced by TDI which may be associated with IL-8 release.