Daniela Spallarossa

Dissociation between exhaled nitric oxide and hyperresponsiveness in children with mild intermittent asthma

BACKGROUND Bronchial hyperresponsiveness and airway inflammation are distinctive features of asthma. Evaluation of nitric oxide (NO) levels in expired air have been proposed as a reliable method for assessing the airway inflammatory events in asthmatic subjects. A study was undertaken to evaluate whether airway hyperresponsiveness is related to levels of exhaled NO. METHODS Thirty two steroid-naive atopic children with mild intermittent asthma of mean (SD) age 11.8 (2.3) years and 28 age matched healthy controls were studied to investigate whether baseline lung function or airway hyperresponsiveness is related to levels of exhaled NO. Airway responsiveness was assessed as the dose of methacholine causing a 20% decrease in forced expiratory volume in one second (FEV1) from control (PD20 methacholine) and exhaled NO levels were measured by chemiluminescence analysis of exhaled air. RESULTS At baseline asthmatic children had significantly higher NO levels than controls (mean difference 25.87 ppb (95% CI 18.91 to 32.83); p<0.0001) but there were no significant differences in lung function parameters (forced vital capacity (FVC), FEV1 (% pred), and forced expiratory flows at 25–75% of vital capacity (FEF25–75%)). In the asthmatic group exhaled NO levels were not significantly correlated with baseline lung function values or PD20 methacholine. CONCLUSIONS These results suggest that levels of exhaled NO are not accurate predictors of the degree of airway responsiveness to inhaled methacholine in children with mild intermittent asthma.

Exhaled nitric oxide levels in non-allergic and allergic mono- or polysensitised children with asthma

BACKGROUND Increased fractional exhaled NO concentrations (Feno) and blood/tissue eosinophilia are frequently reported in allergic children with mild asthma and are thought to reflect the intensity of the inflammation characterising the disease. The aim of this study was to investigate possible differences in Feno levels or in the intensity of the blood eosinophilia in allergic and non-allergic asthmatic children. METHODS 112 children with stable, mild, intermittent asthma with a positive bronchial challenge to methacholine were consecutively enrolled in the study; 56 were skin prick test and RAST negative (non-sensitised) while 56 were sensitised to house dust mites (23 only to house dust mites (monosensitised) and 33 were sensitised to mites and at least another class of allergens (pollens, pet danders, or moulds)). Nineteen sex and age matched healthy children formed a control group. RESULTS Compared with non-allergic patients, allergic children had a significantly higher rate of blood eosinophilia (p=0.0001) with no differences between mono- and polysensitised individuals. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow at 25–75% of vital capacity (FEF25–75%), and the degree of bronchial reactivity to methacholine were similar in non-atopic and atopic children, with no differences between mono- and polysensitised individuals. Feno levels measured by chemiluminescence analyser were higher in asthmatic children (15.9 (14.3) ppb) than in the control group (7.6 (1.6) ppb, p=0.04) and higher in allergic patients (23.9 (2.1) ppb) than in non-allergic patients (7.9 (0.8) ppb, p=0.0001), but there were no differences between mono- and polysensitised individuals (p>0.1). Significant correlations between blood eosinophilia and Feno levels were seen only in allergic (r=0.35, p<0.01) and in polysensitised individuals (r=0.45, p<0.05). CONCLUSIONS In children with mild asthma, a similar degree of functional disease severity may be associated with a higher inflammatory component in allergic than in non-allergic subjects.

Steroid-Naive Adolescents with Mild Intermittent Allergic Asthma Have Airway Hyperresponsiveness and Elevated Exhaled Nitric Oxide Levels

Although atopic asthma symptoms often seem to disappear around puberty, subjects in this age group may experience unexpected, often severe, asthma attacks. This may be related to persistence of untreated airway hyperresponsiveness/inflammation in a life period characterized by low perceptiveness of disease-related symptoms. This study was designed to evaluate the prevalence and the severity of bronchial hyperreactivity and the exhaled nitric oxide (FENO) levels in a group of steroid-naive asthmatic adolescents. Fifty-two patients with mild-intermittent asthma were studied, ages 12 to 16, sensitized to house dust mites; 22 age-matched controls, were also studied. Asthma patients showed FEV1, FEF25–75%, and FVC values not significantly different from controls, (p>0.05, each comparison). By contrast, although none of the control subjects showed bronchial hyperreactivity, increased airway responsiveness to methacholine (MCh) was demonstrated in the majority of the patients and found to be severe in 36.5% (MCh PD20 ≥ 400 µg or accumulative dose ≤1220 µg) and moderate in 32.7% (MCh PD20 400–1400 µg or accumulative dose 1220–4620 µg). In addition, FENO concentrations were significantly higher in asthmatics, as compared with controls (20.4 ± 5.3 ppb and 4.4 ± 0.7 ppb, respectively; p<0.01) and 83% of the patients had FENO levels higher than 8.9 ppb (i.e., >2 standard deviations of the mean in control subjects). A positive, statistically significant correlation was found between FEF25–75% values and MCh PD20 (r = 0.358; p<0.01) or MCh accumulative dose (r = 0.355; p<0.05). No correlations were demonstrated between MCh responsiveness and FVC or FEV1 values or FENO levels and between FENO levels and pulmonary function parameters (p>0.05). The high incidence of bronchial hyperresponsiveness to MCh and of airway inflammation (as demonstrated by the elevated FENO levels) in adolescents with mild asthma suggests the need for more accurate evaluation and, possibly, for early intervention with antiinflammatory drugs in a significant proportion of patients in this age group.

Stimulation of eosinophil IgE low-affinity receptor leads to increased adhesion molecule expression and cell migration

Immunoglobulin binding on eosinophil surface receptors results in activation of these cells. Evaluating blood eosinophils from atopic subjects, it was investigated whether ligation of immunoglobulin E low-affinity receptor (FcepsilonRII/ CD23) with specific monoclonal antibodies (Mabs) resulted in enhanced eosinophil migration and adhesion molecule expression. Eosinophils from 20 subjects with allergic asthma (atopic individuals) and nine nonatopic normal individuals (controls) were purified using Percoll gradients. The effect of antihuman CD23 Mabs on: 1) eosinophil migration through human umbilical vein endothelial cells (HUVECs); and 2) eosinophil expression of the adhesion molecules leukocyte function-associated antigen-1 (LFA-1, CD11a/CD18), macrophage antigen-1 (Mac-1, CD11b/CD18) and very late activation antigen-1 (VLA-4, CD49d/CD29) was evaluated by specific Mab staining and flow cytometric analysis. As compared to controls, freshly isolated eosinophils from atopic individuals showed enhanced migration through HUVECs (p<0.05) and increased LFA-1 expression (p<0.01), but similar Mac-1 and VLA-4 expression (p>0.1 for both). In both controls and atopic individuals, eosinophil incubation with antihuman CD23 Mabs induced a dose-dependent increase in cell migration through HUVECs, significant at antihuman CD23 Mab concentrations of 5 microg x mL(-1) (p>0.05 for all). Similarly, incubation of the cells with antihuman CD23 Mabs induced dose-dependent upregulation of LFA-1 and Mac-1 expression, whereas no changes in VLA-4 expression were observed (p>0.1). Finally, the enhanced eosinophil migration induced by antihuman CD23 Mab stimulation was significantly inhibited by antihuman LFA-1 (84+/-14% (mean+/-SEM); p<0.01) and VLA-4 Mabs (47+/-15%; p<0.05) but not by antihuman Mac-1 Mabs (p>0.1). In both atopic and control subjects, immunoglobulin E, low-affinity receptor stimulation induces functional changes in eosinophils characterized by increased eosinophil migration associated with enhanced late function antigen-1 and Mac-1 expression.

Time-dependent changes in orally exhaled nitric oxide and pulmonary functions induced by inhaled corticosteroids in childhood asthma

Exhaled nitric oxide levels are elevated in asthmatic children and decrease after inhaled steroid treatment. We evaluated the time-dependent changes in fractional exhaled nitric oxide concentration (FENO) and pulmonary function parameters following inhaled steroid therapy. Thirty-nine steroid-naive atopic patients (age 11.92 ± 0.48 years) with mild intermittent asthma and 22 age-matched healthy controls were enrolled in the study; pulmonary functions and FENO levels were measured. Low doses of inhaled steroids were prescribed to all asthmatic patients who were reevaluated in a second visit (between 10 and 40 days after the beginning of the treatment). At the enrolment, asthmatic patients had similar forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC) values (p > 0.05) but reduced forced expiratory flows at 25–75% of the vital capacity (FEF25–75%) values, as compared to controls (p < 0.05). In addition, FENO levels were significantly higher in asthmatics with respect to control subjects (30.8 ± 3.0 and 4.0 ± 0.5 ppb, respectively; p < 0.01). All asthmatics had FENO levels higher than 8.8 ppb (i.e., >2 standard deviations of the mean in controls). After steroid treatment, patients showed significant improvement of FEV1, FVC, and FEF25–75% (p = 0.0001; each comparison) and a reduction of FENO levels (p = 0.0001). A weak significant correlation was found between percent decrease in FENO levels and percent increase in FEV1 (r = 0.33, p = 0.04) or in FEF25–75% (r = 0.4, p = 0.01) after treatment. When changes in FENO levels and in pulmonary function parameters were corrected for days of treatment, significant correlations were still present between percent decrease in FENO levels and percent increase in FEV1 (r = 0.57, p = 0.0004) or percent increase in FEF25–75% (r = 0.45, p = 0.006). Sixteen of the 39 asthmatic patients were evaluated on two occasions after the beginning of treatment, at days 10 and 40. The significant reduction in FENO levels (p < 0.01) and the significant increase in FEV1 and FEF25–75% values observed (p < 0.05) after 10 days did not further improve at day 40. These data show that it is possible to demonstrate early effects of low-dose inhaled steroids in asthmatic children using objective measurements of airway caliber and inflammation.

In childhood asthma the degree of allergen-induced T-lymphocyte proliferation is related to serum IgE levels and to blood eosinophilia.

OBJECTIVE To investigate whether the state of activation of circulating T-cells in childhood asthma could be related to serum IgE levels and/or to blood eosinophilia. METHODS Seventeen atopic asthmatic children, sensitized to Dermatophagoides pteronyssinus (Der p), in stable condition at the time of the study and 15 sex-matched and age-matched controls were studied. The expression of activation surface markers (HLA-DR and CD25) on peripheral blood mononuclear cells (PBMCs) was tested by monoclonal antibodies and FACS analysis, while the PBMC proliferative response to Der p antigens was measured by tritiated thymidine (3HTdR) incorporation. RESULTS As compared to controls, atopic children showed higher eosinophil counts (P < .01), similar lymphocyte counts (P > .1, each comparison) but higher proportion of HLA-DR+ and CD25+ T-lymphocytes (P < .05, each comparison). A significant Der p allergen-induced PBMC proliferation was observed in atopic children (P < .01) but not in controls (P > .1). Both in controls and in atopic children, no correlations were found between lymphocyte counts and eosinophil counts or total or allergen-specific IgE levels (P > .1, each comparison). In contrast, weak correlations were detected between the degree of allergen-induced PBMC proliferation and: a) allergen-specific IgE levels in serum (P < .05) and b) eosinophil counts (P < .05). CONCLUSION These data support the concept that the degree of activation of allergen-specific T-lymphocytes in blood may reflect the intensity of allergic sensitization in childhood asthma.

Blood eosinophilia and degree of sensitization to house dust mites in preschool and school children with asthma.

In allergic asthma, there is convincing evidence that changes in eosinophil and lymphocyte state of activation in blood may reflect disease activity. We evaluated whether simple blood eosinophil or lymphocyte counts in atopic children with asthma could reflect the degree of allergic sensitization. Seventy-six asthmatic children, sensitized to house dust mites (HDM), in stable conditions at the time of the study, and 53 sex- and age-matched controls (CTR) were studied. As compared to CTR, allergic patients showed higher eosinophil numbers and percentages (p < 0.001) but similar lymphocyte numbers and proportions (p > 0.1). Both in CTR and in allergic patients, eosinophil counts did not correlate with lymphocyte counts (p > 0.05; each comparison) but positive correlations were observed between eosinophil numbers and percentages and paper radio immunosorbent test (PRIST) levels or radio-allergo sorbent test (RAST) classes (p < 0.001; each comparison). When allergic asthmatic individuals were subdivided according to their age into two subgroups (Gr), no differences were found in eosinophil and lymphocyte counts and in PRIST levels and RAST values between Gr1 (< or =5 years old [preschool children]) and Gr2 (>5 years old [school children]) (p > 0.05; each comparison). Interestingly, although positive correlations between eosinophil counts and PRIST levels were found in both subgroups (p < 0.05; each comparison), only in Gr2 did eosinophil counts correlate positively with RAST classes (p < 0.001). No correlations between lymphocyte counts and PRIST levels or RAST classes were demonstrated (p > 0.05; each comparison). These data suggest that although blood eosinophilia was similar in preschool and in allergic asthmatic school children sensitized to HDM, only in the oldest children did blood eosinophil counts appear to be related to the degree of HDM-specific sensitization.

Nasal brushing: a clinically useful procedure in pediatric patients with rhinosinusitis?

Sinusitis is a common complication of non-allergic and allergic rhinitis, and can trigger lower respiratory diseases, such as bronchitis and asthma. Standard radiography is unable to give any data about the underlying pathological mechanisms (infectious or allergic) involved and infectious rhinosinusitis is very common in pediatric age, even in allergic patients. We investigated the possibility of obtaining more useful diagnostic information, performing nasal brushing (NB) on 117 children with recurrent respiratory symptoms. The following hypothesis were evaluated: (1) whether NB neutrophil/eosinophil percentages and/or NB culture could predict the radiological evidence of maxillary sinusitis; and (2) whether differences between nonallergic and allergic patients could be detected. In the total patient group and in the nonallergic group, the comparison of NB neutrophil percentages in patients with and without maxillary sinusitis showed a statistically significant difference (median 2 and 18%, respectively; P < 0.001). In the nonallergic group, a NB neutrophil rate > or = 5% was chosen as a cut-off between positive and negative NB diagnosis of rhinosinusitis and NB data were compared with radiological investigations. The results obtained showed that NB was fairly sensitive (91%) and predictive (84%). In allergic patients, neither neutrophil nor eosinophil percentages significantly correlated with the presence of sinusitis. Microbiological studies showed that, even if the presence of bacteria in NB resulted associated with sinusitis, a negative culture was not predictive of the absence of the disease. We therefore suggest that NB describes the present inflammatory status of the upper airways, hence, it is more suitable to describe the inflammation related to ongoing upper respiratory tract infections rather than chronic inflammation due to allergic rhinitis, characterized by relapsing episodes of acute inflammation. In conclusion, we propose to consider NB a reliable tool in the diagnosis of rhinosinusitis, particularly in nonallergic pediatric patients. Compared to standard radiological techniques, NB makes it possible to avoid radiation exposure and gives information about the pathological mechanisms involved in the single patient.

e-NO peak versus e-NO plateau values in evaluating e-NO production in steroid-naive and in steroid-treated asthmatic children and in detecting response to inhaled steroid treatment.

Summary. Airway nitric oxide (NO) production can be measured by chemiluminescence analyzer in children able to perform a single low exhalation. The aim of the present study was to evaluate whether exhaled NO (e‐NO) peaks (first part of the exhalation) were as useful as e‐NO plateaus (last part of the exhalation) in evaluating e‐NO production in asthmatic children and in detecting responses to inhaled steroid treatment. E‐NO peak, plateau, and rate of production values were measured in 100 atopic asthmatic children using a chemiluminescence analyser. Thirty‐seven patients (mean age, 11.1 ± 0.7 years) were receiving inhaled steroids (flunisolide, 0.8–1 mg daily) or beclomethasone (0.2–0.4 mg daily), while the remaining 63 (mean age, 12.0 ± 0.4 yrs) were‐steroid naive and treated only with inhaled β2‐agonists on an as‐needed basis. Fifteen out of the 63 steroid‐naive patients were reevaluated after a short course (3 weeks) of inhaled corticosteroid treatment (flunisolide, 0.8–1 mg daily, or beclomethasone, 0.2–0.4 mg daily).