Does sputum eosinophilia predict the response to systemic corticosteroids in children with difficult asthma?

Little evidence exists to guide the management of children with difficult asthma. The aim of this study was to determine whether children with difficult asthma, associated with sputum eosinophilia, are more likely to benefit from further treatment with high-dose systemic corticosteroids, compared to those without sputum eosinophilia. Induced sputum was obtained from 20 children aged between 8 and 15 years with difficult asthma before and after a systemic corticosteroid trial (prednisolone 40 mg/day for 14 days or a single 80 mg dose of intramuscular triamcinolone). Subjects were defined as "eosinophilic" if the baseline sputum eosinophil percentage was > or = 2.5% or "non-eosinophilic" if < 2.5%. Clinical response to the corticosteroid trial was assessed using spirometry and clinical data and defined by an increase in pre-bronchodilator forced expiratory volume in 1 sec (FEV1) > 9% predicted and/or an overall subjective improvement. Seventeen children had evidence of satisfactory adherence to the systemic corticosteroid treatment; eight of these were "eosinophilic" and nine were "non-eosinophilic" subjects. Following the trial there was a similar clinical improvement in both groups, with FEV1 increasing in both the "eosinophilic" and "non-eosinophilic" groups (median change in FEV1 16 [range 5-54]% vs. 12.5 [1-29]% predicted). Sputum eosinophils fell in the "eosinophilic" group (median 17.5 [range 3-37]% vs. 0 [0-23]%, P = 0.054), with no change in the "non-eosinophilic" group (0 [0-2]% vs. 0 [0-1]%, P = 0.12). Sputum neutrophils did not change in either the "eosinophilic" (22.5 [5-50]% vs. 25 [0-91]%) or the "non-eosinophilic" group (27.5 [0-96] vs. 44 [9-96]%). In conclusion children with difficult asthma may benefit clinically from high-dose systemic corticosteroids even in the absence of sputum eosinophilia.

Airway eosinophilia in children with severe asthma: predictive values of noninvasive tests.

RATIONALE: Children with severe asthma experience persistent symptoms despite maximal conventional treatment. Fraction of exhaled nitric oxide (Fe(NO)) and sputum eosinophils are used as markers of airway inflammation to guide treatment with steroids, but no data are available on how reliable they are in predicting airway eosinophilia assessed bronchoscopically in these children. OBJECTIVES: To determine how Fe(NO) and sputum eosinophils predict airway eosinophilia measured in both bronchoalveolar lavage (BAL) and endobronchial biopsy. METHODS: Twenty-seven children with moderate to severe persistent asthma attempted measurement of Fe(NO) and sputum eosinophils, followed by bronchoscopy, BAL, and endobronchial biopsy within 24 h. MAIN RESULTS: Significant correlations were found between eosinophils in sputum and both BAL eosinophils (n = 20, r = 0.45, p = 0.045) and Fe(NO) (n = 23, r = 0.42, p = 0.049). The relationship between Fe(NO) and BAL eosinophils was also significant with a stronger correlation (n = 24, r = 0.54, p = 0.006). The positive predictive value (PPV) for increased sputum eosinophil percentage (> 2.5%) to detect elevated eosinophils in BAL (> 1.19%) was 75%; the negative predictive value (NPV) was 63%. All patients with both increased sputum eosinophils and an elevated Fe(NO) value (> 23 ppb) had elevated eosinophils in BAL (PPV, 100%); the NPV of these two markers was 65%. Eight of nine patients without any sputum eosinophils had normal subepithelial eosinophil numbers (< 1.2%; NPV, 89%). However, the PPV of any sputum eosinophils for increased subepithelial eosinophilia was only 36.4%. CONCLUSIONS: There was moderate agreement between both Fe(NO) and sputum eosinophils and BAL eosinophils. There was good NPV, but only poor PPV for these markers for mucosal eosinophilia.

Exhaled breath condensate cysteinyl leukotrienes and airway remodeling in childhood asthma: a pilot study.

BACKGROUND: It has been suggested that cysteinyl leukotrienes (cysLTs) play an important role in airway remodeling. Previous reports have indicated that cysLTs augment human airway smooth muscle cell proliferation. Recently, cysLTs have been measured in exhaled breath condensate (EBC). The aim of this study was to evaluate the relationship between cysLTs in EBC and another marker of airway remodeling, reticular basement membrane (RBM) thickening, in endobronchial biopsies in children. METHODS: 29 children, aged 4-15 years, with moderate to severe persistent asthma, who underwent bronchoscopy as part of their clinical assessment, were included. Subjects underwent spirometry and EBC collection for cysLTs analysis, followed by bronchoscopy and endobronchial biopsy within 24 hours. RESULTS: EBC cysLTs were significantly lower in asthmatic children who were treated with montelukast than in those who were not (median (interquartile range) 36.62 (22.60-101.05) versus 249.1 (74.21-526.36) pg/ml, p = 0.004). There was a significant relationship between EBC cysLTs and RBM thickness in the subgroup of children who were not treated with montelukast (n = 13, r = 0.75, p = 0.003). CONCLUSION: EBC cysLTs appear to be associated with RBM thickening in asthma.

Measurement of bronchial and alveolar nitric oxide production in normal children and children with asthma.

RATIONALE: Airway inflammation is characteristic of asthma. Distal inflammation may be particularly important. OBJECTIVE: To calculate alveolar nitric oxide (NO) concentration (C(alv)) and bronchial flux NO (J(NO)) in children. METHODS: We measured C(alv) and J(NO) from the fractional exhaled NO (FeNO(50)) measured at multiple exhalation flow rates in 132 children (aged 4-18 yr) with known atopic status, medication, and asthma control. MEASUREMENTS AND MAIN RESULTS: Of participants, 85% (112/132) completed all measurements. In 20 of 112, the result did not fit the linear model. Thus, J(NO) and C(alv) were assessed in 92 (70%) subjects. The median (range) values of asthmatic (n = 52), normal (n = 20), and nonasthmatic atopic (n = 20) children were as follows: FeNO(50): 28.1 (4.3-190), 10.35 (3.3-29), 21.8 (8.7-69) ppb, respectively; J(NO): 1,230 (204-9,236), 480 (196-1,913), 1,225 (486-4,119) pl/s, respectively; C(alv): 2.22 (0.44-6.63), 1.63 (0.44-3), 1.21 (0.03-2.85) ppb, respectively. A reproducibility study in 18 other children gave intraclass correlation coefficients (single measures) of 0.99 (J(NO)) and 0.81 (C(alv)). J(NO) and C(alv) were higher in children with asthma than normal children (p = 0.0004 and p = 0.0002, respectively). Children with poorly controlled asthma (n = 27) had higher FeNO(50) measurements than children with good symptom control (n = 25): C(alv): mean (+/- SD), 3.17 +/- 1.62 versus 2.26 +/- 1.30 ppb, p = 0.03; J(NO): mean (+/- SD), 2,634 +/- 2,255 versus 1,193 +/- 1,294 pl/s, p = 0.007, respectively. CONCLUSIONS: Measurement of J(NO) and C(alv) is feasible in 70% of school-age children. FeNO(50) and J(NO) give the same information (r = 0.97, p < 0.0001), C(alv) is higher in asthmatic children than in normal children and is affected by asthma control, but not by atopy. C(alv) may possibly reflect alveolar inflammation in asthma.

Exhaled 8-isoprostane in childhood asthma.

BACKGROUND: Exhaled breath condensate (EBC) is a non-invasive method to assess airway inflammation and oxidative stress and may be useful in the assessment of childhood asthma. METHODS: Exhaled 8-isoprostane, a stable marker of oxidative stress, was measured in EBC, in children (5-17 years) with asthma (13 steroid-naïve and 12 inhaled steroid-treated) and 11 healthy control. RESULTS: Mean exhaled 8-isoprostane concentration was significantly elevated in steroid-naïve asthmatic children compared to healthy children 9.3 (SEM 1.7) vs. 3.8 (0.6) pg/ml, p < 0.01. Children on inhaled steroids also had significantly higher 8-isoprostane levels than those of normal subjects 6.7 (0.7) vs. 3.8 (0.6) pg/ml, p < 0.01. Steroid-naïve asthmatics had higher exhaled nitric oxide (eNO) than those of controls 28.5 (4.7) vs. 12.6 (1.5) ppb, p < 0.01. eNO in steroid-treated asthmatics was similar to control subjects 27.5(8.8) vs. 12.6(1.5) ppb. Exhaled 8-isoprostane did not correlate with duration of asthma, dose of inhaled steroids or eNO. CONCLUSION: We conclude that 8-isoprostane is elevated in asthmatic children, indicating increased oxidative stress, and that this does not appear to be normalized by inhaled steroid therapy. This suggests that 8-isoprostane is a useful non-invasive measurement of oxidative stress in children and that antioxidant therapy may be useful in the future.

Is a two-week trial of oral prednisolone predictive of target lung function in pediatric asthma?

We used a 2-week trial of prednisolone to determine "target" lung function for subsequent asthma therapy. The aim of this study was to evaluate whether some children exceed their "target" forced expired volume in 1 sec (FEV1) on subsequent visits in the following year, and whether this is associated with particular clinical or pathological features. Children (aged 6-16 years) with difficult asthma underwent spirometry and exhaled nitric oxide (FE(NO)) measurements before and after 2 weeks of prednisolone 40 mg/day. At the end of the course, subepithelial eosinophils and reticular basement membrane thickness were assessed. The highest FEV1 obtained in a 1-year follow-up was compared with the poststeroid postbronchodilator ("target") FEV1. Four of 22 children (18%) demonstrated an increase of > 9% above their "target" FEV1 during follow-up. None of these children had been prescribed additional asthma medications. Three of 7 children with persistent airflow limitation (PAL; poststeroid postbronchodilator FEV1 < 80% predicted) recorded an FEV1 > 80% predicted during follow-up. The median (interquartile range) number of subepithelial eosinophils was significantly higher in children who exceeded their target FEV1 than in children who did not (12.4 (8.5-39.9) vs. 1.4 (0.0-4.8) cells/mm2, P = 0.018). In conclusion, a 2-week course of prednisolone is not necessarily predictive of "target" lung function. Definitions such as PAL should be regularly reviewed on individual basis.

Sputum induction in children with difficult asthma: safety, feasibility, and inflammatory cell pattern.

Difficult childhood asthma is defined by persistent symptoms despite maximal conventional therapy. We aimed to establish a safe method of sputum induction for these children and to study cytology and the relationship to exhaled nitric oxide (eNO). Sputum induction was performed in 38/40 children (aged 6-16 years) with difficult asthma, using 3.5% saline for four 5-min periods after bronchodilator pretreatment. Two children were excluded from sputum induction because postbronchodilator forced expired volume in 1 sec (FEV(1)) was <65% predicted. Seven of 38 children had symptoms (dyspnea and wheezing) during induction; of these, 3 experienced a fall in FEV(1) of >20% from postbronchodilator FEV(1), readily reversed with salbutamol. Sputum induction was successful in 28/38 children, with a higher success rate in children >/= 12 years than in younger children (87% vs. 50%, P = 0.02). Only 9/28 had abnormal sputum cytology; of these, 6 had predominant sputum eosinophilia (>2.5% eosinophils, 54% neutrophils). Of 23 children with elevated eNO values, only 6 had sputum eosinophilia. In conclusion, sputum induction can be used to assess airway inflammation in children with difficult asthma, but abnormal sputum cytology is only present in a minority. Raised nitric oxide is only poorly predictive of sputum eosinophilia in these children.

Symptoms, lung function, and beta2-adrenoceptor polymorphisms in a birth cohort followed for 10 years.

As little is known about the natural history of bronchial responsiveness and the development of wheezing symptoms in early childhood, a cohort of children at risk of allergy, whose lung function and bronchial responsiveness had been measured in the neonatal period, was followed prospectively for 10 (SD, 0.8) years in order to determine the role of neonatal measurements on wheezing history and later lung function. A potential role for beta-2 adrenoceptor (beta2AR) polymorphisms in these relationships was also sought as a secondary objective. Of the original 73 children, wheezing history was available in 65 (89%), and 49 (67%) attended the laboratory for physiological measurements and genotyping of beta2AR. Wheezing was categorized as occurring 1) only before the fourth birthday, 2) after the fourth birthday, or 3) never. No relation was seen between neonatal and later lung function. However, neonatal bronchial responsiveness predicted subsequent FEV1 (P = 0.03). Increased neonatal bronchial responsiveness was associated with transient wheeze <4 years but not with later wheeze. Neonatal V'maxFRC was reduced in those possessing Gln27 or Arg16 alleles, but there was no effect of beta2AR polymorphisms on FEV1 at 10 years. Wheeze after 4 years of age was typical of classical asthma, as it was strongly related to atopy and bronchial responsiveness at age 10. In conclusion, we confirmed the association of neonatal bronchial responsiveness with both early wheezing and later lung function. We also showed an influence of polymorphisms at both aa16 and aa27 on neonatal lung function. Wheezing beyond 4 years, typical of classical asthma, was unrelated to early measurements of lung function or bronchial responsiveness.

Nitric oxide metabolites are not reduced in exhaled breath condensate of patients with primary ciliary dyskinesia.

STUDY OBJECTIVES: To investigate whether nitric oxide (NO) metabolites would be reduced in children affected by primary ciliary dyskinesia (PCD). DESIGN: Single-center observational study. PATIENTS: Fifteen children with PCD (seven boys; mean [+/- SEM] age, 10.3 +/- 0.7 years; mean FEV(1), 73 +/- 2.1% predicted) were recruited along with 14 healthy age-matched subjects (seven boys; mean age, 11.5 +/- 0.4 years; mean FEV(1), 103 +/- 5% predicted). INTERVENTIONS: We assessed the levels of nitrite (NO(2)(-)), NO(2)(-)/NO(3)(-) (NO(2)(-)/NO(3)(-)), and S-nitrosothiol in exhaled breath condensate, exhaled NO, and nasal NO from children with PCD compared to those in healthy children. MEASUREMENTS AND RESULTS: The mean exhaled and nasal NO levels were markedly decreased in children with PCD compared to those without PCD (3.2 +/- 0.2 vs 8.5 +/- 0.9 parts per billion [ppb], respectively [p < 0.0001]; 59.6 +/- 12.2 vs 505.5 +/- 66.8 ppb, respectively [p < 0.001]). Despite the lower levels of exhaled NO in children with PCD, no differences were found in the mean levels of NO(2)(-) (2.9 +/- 0.4 vs 3.5 +/- 0.3 microM, respectively), NO(2)(-)/NO(3)(-) (35.2 +/- 5.0 vs 34.3 +/- 4.5 microM, respectively), or S-nitrosothiol (1.0 +/- 0.2 vs 0.6 +/- 0.1 microM, respectively) between children with PCD and healthy subjects. CONCLUSION: These findings suggest that NO synthase activity may not be decreased as much as might be expected on the basis of low exhaled and nasal NO levels.

Virus infections, wheeze and asthma.

Viral infections are the most frequent triggers of wheeze and asthma and yet their role in the development of symptoms remains controversial. Pre-existing airway abnormalities contribute to early virus-induced symptoms which usually remit in early childhood, whereas an interaction with airway inflammation causes exacerbations in asthma. However, the distinction between these two groups and the reason why some but not other children wheeze with viral infections is still debated. The effect of early infections on the developing immune system is also complex. The successful maturation of the T-cell response from a predominantly type 2 (atopic predisposition) at birth to a predominantly type 1 (optimal viral immunity) response, is influenced by genetic factors and the number of infections, as both are known to affect outcome. The relative parts played by predisposition and immunomodulation by early infections in later development of asthma are still controversial. These contentions are gradually being resolved by detailed prospective studies.

Increased leukotrienes in exhaled breath condensate in childhood asthma.

Cysteinyl leukotrienes (cys-LTs; LTC4, LTD4, and LTE4) are generated predominantly by mast cells and eosinophils and induce airway smooth muscle contraction, microvascular leakage, and mucous hypersecretion whereas leukotriene B4 (LTB4) is a potent chemoattractant of neutrophils. We measured cys-LTs and LTB4 in exhaled breath condensate from children aged 7-14 years including healthy nonatopic children (n = 11) and children with mild intermittent asthma (steroid naive, n = 11), mild persistent asthma (low-dose inhaled steroid treatment, n = 13), or moderate to severe persistent asthma (high-dose inhaled steroid treatment, n = 13). Exhaled LTB4 levels were increased in patients with mild and moderate to severe persistent asthma compared with patients with mild intermittent asthma (126.0 +/- 8.8 and 131.9 +/- 7.1 versus 52.7 +/- 3.8 pg/ml, p < 0.001 and p < 0.0001) and normal subjects (126.0 +/- 8.8 and 131.9 +/- 7.1 versus 47.9 +/- 4.1 pg/ml, p < 0.0001). Elevated exhaled cys-LT levels were found in patients with mild and moderate to severe persistent asthma compared with normal subjects (27.9 +/- 2.8 and 31.5 +/- 4.5 versus 18.5 +/- 0.5 pg/ml, p < 0.01 and p < 0.05). There was an inverse correlation between exhaled cys-LTs and LTB4 in patients with mild persistent asthma. We conclude that exhaled cys-LTs and LTB4 may be noninvasive markers of airway inflammation in pediatric asthma.

Increased interleukin-4 and decreased interferon-gamma in exhaled breath condensate of children with asthma.

Exhaled breath condensate analysis for noninvasive quantification of airway inflammation in asthma is a potentially useful research tool in children. There is an imbalance between T-helper (Th)-2 cells, which secrete interleukin (IL)-4, and Th1 cells, which secrete interferon (IFN)-gamma, in asthma. We measured concentrations of IL-4 and IFN-gamma in breath condensates of 37 children (11 normal, 12 steroid-naive, and 14 steroid-treated children with asthma). Exhaled IFN-gamma was significantly lower in steroid-naive and steroid-treated children with asthma compared with normal control subjects (3.7 +/- 0.2 versus 5.1 +/- 0.4 pg/ml, p < 0.01 and 4.1 versus 5.1 pg/ml, p < 0.05). By contrast, mean exhaled IL-4 was elevated in asthma (53.7 +/- 4.2 pg/ml) compared with normal children (35.7 +/- 6.2 pg/ml, p < 0.05) and concentrations were lower with steroid treatment (37.5 +/- 5.6 pg/ml, p < 0.05). Exhaled IL-4 was significantly lower in children with asthma on more than 600 microg inhaled steroid/day. The IL-4/IFN-gamma ratio was significantly greater in children with asthma compared with control children and the children with asthma on inhaled steroid therapy. We have shown for the first time that IFN-gamma and IL-4 can be assayed in exhaled breath condensate and shows an increased ratio of IL-4/IFN-gamma, consistent with predominance of Th2 cells in airways of children with asthma. Exhaled breath condensate analysis may have a useful role in studying allergic inflammation in childhood asthma.