Clinical and immunologic factors associated with the presence or absence of airways hyper-responsiveness in childhood asthma

Relationships of indoleamine 2,3-dioxygenase activity and cofactors with asthma and nasal polyps

BACKGROUND

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNPs) are coexisting diseases that are multifactorial. The rural environment seems to protect from atopy, but its relation with nonatopic airway inflammations has been less investigated. Indoleamine 2,3-dioxygenase (IDO) is an enzyme involved in the catabolism of the essential amino acid tryptophan (Trp) to kynurenine (Kyn). Low IDO activity has been previously observed in atopy and asthma. The objective was to investigate the relationships of IDO activity, eosinophils, and cofactors during asthma and/or CRSwNPs.

METHODS

A Finnish population-based cohort of adult asthmatic patients (n = 245) and nonasthmatic patients (n = 405) was used. The presence of asthma and atopy were based on patient history and standardized diagnostic tests. The presence of acetyl salicylic acid intolerance, doctor-diagnosed NPs, and countryside environment during childhood were based on a questionnaire report. Serum IDO activity was evaluated by assessing the Kyn/Trp ratio by liquid chromatography.

RESULTS

Low IDO activity was associated significantly with atopy, CRSwNPs, and an urban background. IDO activity did not correlate with pulmonary function. As expected, CRSwNPs was more frequent among asthmatic patients. A rural background has a protective effect from atopy and atopic asthma but it did not affect the prevalence of CRSwNPs or nonatopic asthma.

CONCLUSION

Low IDO activity might result from the urban environment and influence the development of the atopic phenotype. On the other hand, low IDO activity, found in CRSwNPs, does not seem to be related to the urban background and thus may result from other, still unknown, factors.

The impact of breastfeeding on lung development and function: a systematic review

With the global trend of increasing asthma and allergic disorders there is strong interest regarding early life nutrition as a potentially modifiable risk factor for lung disease. This systematic review includes 10 studies that assessed the effect of breastfeeding on lung growth and function. The review found breastfeeding to be beneficial for lung function, with the most consistent effect on increased forced vital capacity. There was no clear evidence that the relationship between breastfeeding and lung function was mediated through other factors. Furthermore, the findings from the few studies that investigated if maternal asthma modified the effect of breastfeeding on lung function were inconsistent. Further research is needed to determine the specific details such as duration and type (exclusive vs partial) of breastfeeding that leads to improved lung function.

Airway hyperresponsiveness is associated with total serum immunoglobulin E and sensitization to aeroallergens in Korean adolescents

BACKGROUND

Allergen sensitization and airway hyperresponsiveness (AHR) are the most important characteristics of bronchial asthma and their correlation has been speculated.

OBJECTIVE

We attempted to investigate the relationship between sensitization to allergens and AHR to methacholine in Korean high school students.

METHODS

A questionnaire survey, methacholine bronchial provocation tests, and skin-prick tests for 16 major allergens were performed on 724 students. The mean age of participants was 15.79 ± 0.40 years old. Serum total immunoglobulin E (IgE) and the fraction of blood eosinophils were measured.

RESULTS

AHR (PC(20) < 16 mg/ml) was present in 12.3%. Log total IgE was higher in AHR-positive group than negative group (4.22 ± 1.55, 3.70 ± 1.33, P = 0.001). Three hundred eighty-four students (53.0%) were sensitized to more than one allergen, and among them Dermatophagoides pteronyssinus (Der p, 295 students, 40.7%) and Dermatophagoides farinae (Der f, 301 students, 41.6%) were most common. The risk of AHR development was high in the group who had sensitization to one allergen (adjusted odds ratio [aOR] = 1.97, 95% confidence interval [CI]: 1.13-3.44, P = 0.018) and to more than two allergens (aOR = 2.94, 95% CI: 1.32-6.57, P = 0.009). Among the specific allergens, AHR was developed in those who were sensitized to Der f (aOR = 1.73, 95% CI: 1.04-2.86, P = 0.033), dog dander (aOR = 3.97, 95% CI: 1.67-9.51, P = 0.002), and Alternaria (aOR = 3.19, 95% CI: 1.24-6.41, P = 0.016). In the groups with high IgE (>300 IU/ml) and high eosinophil fraction (>4%), AHR was more developed than groups who were low in each (aOR = 2.73, 95% CI: 1.15-6.51, P = 0.023; aOR = 10.82, 95% CI: 3.33-35.08, P = 0.001).

CONCLUSION

The risk of AHR development was closely linked with allergen sensitization itself, and the number or types of sensitized allergens such as indoor and fungal allergens in Korean young adolescents.

Airway hyper-responsiveness to adenosine 5'-monophosphate in preschool-age children with asthma

Airway hyper-responsiveness (AHR) to adenosine 5'-monophosphate (AMP) is closely associated with airway inflammation; however, not all asthmatic patients are responsive to it. This study was planned to investigate the predictive factors of AHR to AMP in asthmatic children aged between 3 and 6 yr. We performed a retrospective analysis of data from 63 asthmatic preschool-age children who were challenged by AMP in our department. All children were characterized by skin-prick tests, serum immunoglobulin E (IgE) levels, peripheral blood eosinophil percentage and bronchial challenge with methacholine (MCH) and AMP. Potential determinants for AHR to AMP were assessed within the group. AHR to AMP was found in 46% of preschool-age children with asthma, while that of MCH was 93.7%. All children responsive to AMP were also responsive to MCH. The geometric mean provocative concentration of MCH and AMP causing a 15% fall in transcutaneous oxygen tension (PC(15)PtcO(2)MCH and AMP) were 0.55 mg/ml (0.004-9.19) and 10.53 mg/ml (0.59-342.89), respectively. AMP-responsive children did not differ from non-responsive ones with respect to demographic factors, geometric mean PC(15)PtcO(2)MCH and atopic status. The median serum IgE level was significantly higher in AMP-responsive group than the non-responsive ones (p = 0.011). The peripheral blood eosinophilia was more frequent among responsive children (p = 0.019), and it was found as the only predictive factor for AMP responsiveness in preschool-age children with asthma in logistic regression model (odds ratio: 5.14; 95% CI: 1.23-21.47; p = 0.025). AMP responsiveness may be predicted by peripheral blood eosinophilia but not with atopy markers in young children with asthma.

Bronchial hyperresponsiveness, atopy, and bronchoalveolar lavage eosinophils in persistent middle lobe syndrome

Most cases of middle lobe syndrome (MLS) in children are considered to be due to asthma and may recover spontaneously; however, in persistent MLS, repeated episodes of infection often institute a vicious cycle that may lead to persistent symptoms and bronchial hyperresponsiveness (BHR). The present study was undertaken to investigate whether asthma, as an underlying diagnosis, is predictive of a favorable outcome of children with persistent MLS. We evaluated 53 children with MLS who underwent an aggressive management protocol that included fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL). These patients were compared to two other groups: one consisting of children with current asthma but no evidence of MLS (N = 40) and another of non-asthmatic controls (N = 42), matched for age and sex. Prevalence of sensitization (>or=1 aeroallergen) did not differ between patients with MLS and "non-asthmatics" but was significantly lower than that of "current asthmatics." A positive response to methacholine bronchial challenge was observed with increased frequency among children with MLS when compared to "current asthmatic" and non-asthmatic children. Multivariate logistic regression analysis revealed a positive correlation between an increased number of eosinophils in the BAL fluid (BALF) and a favorable outcome, whereas no correlation was detected between sensitization or BHR and BAL cellular components. In conclusion, children with MLS have an increased prevalence of BHR, even when compared to asthmatics, but exhibit prevalence of atopy similar to that of non-asthmatics. An increased eosinophilic BALF count is predictive of symptomatic but not radiographic improvement of MLS patients after aggressive anti-asthma management.

Sensitization to aeroallergens and airway hyperresponsiveness at 7 years of age

STUDY OBJECTIVES

To investigate the relationship between current and early life factors and airway responsiveness to inhaled methacholine in children with a median age of 7.0 years.

PARTICIPANTS

Study subjects were a subset of a prospective birth cohort of children in the Boston area at high risk for atopy.

METHODS

One hundred thirty-one children underwent both skin-prick testing to a panel of aeroallergens and a methacholine challenge test between 6.5 years and 8.8 years of age. Telephone questionnaires were performed at set intervals, and home dust samples were collected in the first year of life.

RESULTS

Of the 131 participating children, 51% (67 patients) had at least one positive skin-prick test response and 28% (37 patients) had airway hyperresponsiveness (AHR) [provocative concentration of methacholine causing a 20% fall in FEV(1) of < 4 mg/mL]. After adjusting for relevant covariates, AHR was strongly associated with sensitization to at least four aeroallergens (odds ratio [OR], 13.41; 95% confidence interval [CI], 3.03 to 59.42). In separate adjusted models, sensitization to cat (OR, 14.73; 95% CI, 3.64 to 59.55), dust mite (OR, 5.13; 95% CI, 1.94 to 13.56), cockroach (OR, 4.00; 95% CI, 1.19 to 13.50), and ragweed (OR, 10.08; 95% CI, 2.31 to 44.10) were significant predictors of AHR. However, no relationship was found with early life exposure to perennial aeroallergens or other perinatal and first-year-of-life factors.

CONCLUSIONS

Among young children at risk for atopy, sensitization to specific aeroallergens, but not early life exposures, is associated with increased airway responsiveness.

Exhaled markers in the monitoring of airways inflammation and its response to steroid's treatment in mild persistent asthma

The measure of inflammatory cytokines in the exhaled breath condensate has been recently proposed for use in monitoring asthma and the therapeutic response to steroids. The aim of the present study was to investigate the usefulness of measuring exhaled IL-6, IL-4 and pH in mild persistent asthma. Furthermore the effects on these markers of inhaled steroids were assessed. The study enrolled 28 asthmatic (15 males, 38+/-12 years) and 15 healthy subjects (5 males, 35+/-6 years). IL-6, IL-4 and pH were measured in the exhaled breath condensate of the subjects studied. Significantly higher concentrations of IL-6 and IL-4 were observed in the breath condensate of asthmatic patients (7.1+/-1.1 and 64.4+/-8.3 pg/ml) compared to controls (2.7+/-0.6 and 31.7+/-3.5 pg/ml), p<0.001. Furthermore, exhaled IL-4 fell significantly after treatment with inhaled steroids for 6 months (47.9+/-3.2 pg/ml, p<0.001) while exhaled IL-6 did not (6.4+/-1.0 pg/ml, p=0.8). The exhaled pH turned out to be lower in asthmatic subjects than in controls (7.39+/-0.11 vs. 7.85+/-0.14; P<0.001) but trended towards control levels after steroid treatment (7.65+/-0.16, P<0.001). We conclude that the measurement of exhaled IL-4 and pH in mild asthmatic subjects could be a useful way of monitoring their airway inflammation as well as their response to the treatment.