Normal variation of bronchial reactivity in nonasthmatics is associated with the level of mite-specific IgE

Sensitization profile in differential diagnosis: allergic asthma vs. chronic (nonspecific) cough syndrome

BACKGROUND

In the subgroup of children with chronic cough, distinguishing children with allergic asthma from those with non-specific respiratory symptoms is difficult. We have focused on determination of diagnostic efficiency of serum total IgE, sIgE, and skin prick test in differentiation of asthmatic children from children with nonspecific respiratory symptoms.

MATERIAL AND METHODS

A total of 131 children with median age of 7.5 years were enrolled in study and divided into 2 groups; children with allergic asthma (N=71) and children with chronic cough (N=60). Participants underwent the standard allergological examination, including skin prick test and measurement of total IgE, and following 3 allergen-specific IgE antibodies against aeroallergens: Dermatophagoides pteronyssinus, Ambrosia artemisiifolia, and Phleum pratense.

RESULTS

The percentage of patients with elevated level of total and sIgE was higher in children with allergic asthma than in children with chronic cough syndrome (P=0.0001). In children with asthma, sIgE had a better diagnostic value than total IgE. The best diagnostic efficiency of cut-off values for sIgE was shown for Der p sIgE. Skin prick test to all allergens had 78.82% sensitivity and 91.3% specificity in differentiating the 2 tested groups. The highest sensitivity and specificity in skin prick test was proved for Dermatophagoides pteronyssinus.

CONCLUSIONS

The sensitization profile consisting of total IgE, sIgE levels, and SPT clearly distinguishes children with allergic asthma from children with chronic nonspecific cough, but still with overlap. Therefore, diagnosis should always be confirmed by a thorough allergy investigation.

Asthma, atopy and exhaled nitric oxide in a cohort of 6-yr-old New Zealand children

BACKGROUND

Exhaled nitric oxide has been promoted as a non-invasive measure of airway inflammation, with clinical utility for the diagnosis and management of asthma.

AIM

We studied associations between exhaled nitric oxide, asthma and atopy in a variety of clinically relevant phenotypes in a cohort of 6-yr-old children.

METHOD

Asthma was defined using standard questionnaire criteria, atopy was measured using skin prick tests (SPT) and specific IgE to common allergens, and exhaled nitric oxide was measured using a chemiluminescence analyser according to American and European Thoracic Society criteria.

RESULTS

Exhaled nitric oxide was strongly related to atopy and in particular to sensitization to house dust mites. Children with non-allergic asthma had no increase in exhaled nitric oxide compared with non-asthmatic children. Compared with children who never wheezed both late onset and persistent, wheezing was associated with increased FE(NO), while early transient wheezing was not. Elevated levels of exhaled nitric oxide amongst children with allergic asthma were almost entirely explained by their levels of specific IgE to aeroallergens, predominantly D pteronyssinus.

CONCLUSION

Airway inflammation as measured by exhaled nitric oxide in young New Zealand children is related to their level of specific IgE to aeroallergens. This has implications for the utility of nitric oxide as a diagnostic and management tool in childhood asthma and for the importance of specific IgE as a marker of asthma severity.

Quantification of atopy, lung function and airway hypersensitivity in adults

BACKGROUND

Studies in children have shown that concentration of specific serum IgE (sIgE) and size of skin tests to inhalant allergens better predict wheezing and reduced lung function than the information on presence or absence of atopy. However, very few studies in adults have investigated the relationship of quantitative atopy with lung function and airway hyperresponsiveness (AHR).

OBJECTIVE

To determine the association between lung function and AHR and quantitative atopy in a large sample of adults from the UK.

METHODS

FEV1 and FVC (% predicted) were measured using spirometry and airway responsiveness by methacholine challenge (5-breath dosimeter protocol) in 983 subjects (random sample of 800 parents of children enrolled in a population-based birth cohort enriched with 183 patients with physician-diagnosed asthma). Atopic status was assessed by skin prick tests (SPT) and measurement of sIgE (common inhalant allergens). We also measured indoor allergen exposure in subjects' homes.

RESULTS

Spirometry was completed by 792 subjects and 626 underwent methacholine challenge, with 100 (16.0%) having AHR (dose-response slope>25). Using sIgE as a continuous variable in a multiple linear regression analysis, we found that increasing levels of sIgE to mite, cat and dog were significantly associated with lower FEV1 (mite p = 0.001, cat p = 0.0001, dog p = 2.95 × 10-8). Similar findings were observed when using the size of wheal on skin testing as a continuous variable, with significantly poorer lung function with increasing skin test size (mite p = 8.23 × 10-8, cat p = 3.93 × 10-10, dog p = 3.03 × 10-15, grass p = 2.95 × 10-9). The association between quantitative atopy with lung function and AHR remained unchanged when we repeated the analyses amongst subjects defined as sensitised using standard definitions (sIgE>0.35 kUa/l, SPT-3 mm>negative control).

CONCLUSIONS

In the studied population, lung function decreased and AHR increased with increasing sIgE levels or SPT wheal diameter to inhalant allergens, suggesting that atopy may not be a dichotomous outcome influencing lung function and AHR.

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.

Decreased risk for atopic disorder associated with highly hyperreactive tuberculin skin test reaction in children and adolescents

BACKGROUND

It is speculated that the exposure to Mycobacterium tuberculosis, either by infection or by Bacillus Calmette-Guérin vaccination, may inhibit the onset of atopy by the modification of immune profiles leading to a shift of T(H)1/T(H)2 balance to the T(H)1 side.

OBJECTIVE

One hundred eighty-six patients hyperreactive at tuberculin skin test (TST) were examined in order to investigate the prevalence of atopic disorder, particularly referring to the association between the size of the TST induration and the prevalence of sensitization and manifest atopic disorder.

METHODS

The study consisted of a family history record, patients' medical history assessment and clinical examination, skin prick test (SPT), serum total and allergen-specific IgE (sIgE) measurement and eosinophil count.

RESULTS

Atopic disorder was present in 49 (26.3%) patients tested. No significant difference between the groups based on the TST induration size (15-24 mm vs. > or =25 mm) was found for gender distribution, family atopy history, total IgE measurement, eosinophil count, positive SPT, and the presence of sIgE. A significant difference was found for the age median (14.0 years vs. 13.0 years), childhood atopy record, and manifest atopic disorder. No association between the size of the TST induration and the incidence of allergic sensitization was demonstrated. However, a significant inverse association between the size of the TST induration and manifest atopic disorder was demonstrated.

CONCLUSION

In patients highly hyperreactive at TST, the size of the induration is inversely associated with manifest atopic disorder.