Wheat allergy in children - new tools for diagnostics

BACKGROUND

The detection of wheat-specific IgE in children often leads to a suspicion of wheat allergy, but little information is available on the most reliable wheat allergens for predicting clinical reactivity.

OBJECTIVE

To evaluate the role of allergenic components of wheat in wheat allergy diagnostics.

METHODS

One hundred and eight children (median age 1.5 years; range 0.6-17.3 years) with suspected wheat allergy underwent open or double-blinded, placebo-controlled oral wheat challenges. Responsiveness to different allergenic components of wheat was studied by skin prick tests and by determination of serum IgE antibodies using a semi-quantitative microarray assay.

RESULTS

Thirty (28%) children reacted with immediate symptoms, and 27 (25%) with delayed symptoms to ingested wheat, whereas 51 (47%) children exhibited no reactions in oral wheat challenges. Positive IgE responses to any of the 12 allergenic components of wheat was seen in 93%, 41%, and 43% of those with immediate, delayed or no reactions to ingested wheat, respectively (P < 0.001 to P < 0.05 in every comparisons between those with immediate reactions and those with no reactions). Positive IgE responses to ≥5 different allergenic components improved significantly the diagnostic accuracy (with a positive likelihood ratio (LR+) of 5.10). Alpha-amylase inhibitors (AAI), in particular dimeric AAI 0.19 (LR+ 6.12), alpha-, beta-, and gamma-gliadins (LR+ from 3.57 to 4.53), and high-molecular-weight (HMW) glutenin subunits (LR+ 4.37) were the single allergenic components of wheat differentiating most effectively those with immediate symptoms from those who did not exhibit any reactions.

CONCLUSIONS AND CLINICAL RELEVANCE

Wheat allergy diagnostics is difficult, even using sophisticated component methods. Our results confirm earlier findings about gliadins and identify the dimeric AAI 0.19, as a relevant allergen in clinically reactive patients when compared to non-reactive subjects. The accuracy of wheat allergy diagnosis may be improved by measuring IgE responses to several components of wheat.

Lifestyle factors and sensitization in children - the ALADDIN birth cohort

BACKGROUND

Several cross-sectional studies indicate that an anthroposophic lifestyle reduces the risk of allergy in children. We initiated the Assessment of Lifestyle and Allergic Disease During Infancy (ALADDIN) birth cohort to elucidate the role of specific factors supposed to mediate this effect. The aims of this study are to describe the ALADDIN cohort and to report patterns of exposure and allergic sensitization during the first years of life.

METHODS

The ALADDIN study is a prospective birth cohort study of 330 children from families with an anthroposophic, partly anthroposophic, or nonanthroposophic lifestyle. The children and their parents were following an extensive data collection scheme, including repeated questionnaires and biological samples. Blood samples were collected from the parents and from the child at birth as well as at 6, 12, and 24 months of age.

RESULTS

Several lifestyle factors differed between the groups, such as diet, medication, and place of delivery. Children of families with an anthroposophic lifestyle had a markedly decreased risk of sensitization during the first 2 years of life compared with children of nonanthroposophic families with adjusted OR 0.25 (95% CI 0.10-0.64) and P-value 0.004. A similar situation held true for children from families with a partly anthroposophic lifestyle, adjusted OR 0.31 (95% CI 0.15-0.54), and P-value 0.002.

CONCLUSIONS

The anthroposophic lifestyle comprises several factors of interest for allergy development and is here shown to be associated with reduced risk of IgE sensitization already in infancy. Identifying the factors responsible for this association would be of significant clinical importance.

The management of the allergic child at school: EAACI/GA2LEN Task Force on the allergic child at school

Allergy affects at least one-quarter of European schoolchildren, it reduces quality of life and may impair school performance; there is a risk of severe reactions and, in rare cases, death. Allergy is a multi-system disorder, and children often have several co-existing diseases, i.e. allergic rhinitis, asthma, eczema and food allergy. Severe food allergy reactions may occur for the first time at school, and overall 20% of food allergy reactions occur in schools. Up to two-thirds of schools have at least one child at risk of anaphylaxis but many are poorly prepared. A cooperative partnership between doctors, community and school nurses, school staff, parents and the child is necessary to ensure allergic children are protected. Schools and doctors should adopt a comprehensive approach to allergy training, ensuring that all staff can prevent, recognize and initiate treatment of allergic reactions.

Blood pressure and cardiovascular autonomic function in healthy children and adolescents

OBJECTIVES

To investigate the relationship between blood pressure levels and cardiovascular autonomic function in adolescents and preadolescents.

STUDY DESIGN

We measured variability of beat-to-beat arterial pressure and R-R intervals using power spectral analysis in 56 adolescents (aged 13-16 years; mean age, 9.0 +/- 1.4 years) and 71 preadolescents (6-12 years; mean age, 13.5 +/- 1.1 years) in the supine and standing positions.

RESULTS

Adolescents had higher levels of systolic arterial pressure and lower high-frequency power of RR intervals than preadolescents. Correlation between the basal level of arterial pressure and autonomic function was observed in adolescents but not in preadolescents. In adolescents, multivariate analysis indicated that the basal level of arterial pressure was inversely related with the high-frequency power of RR intervals and positively with the ratio of low-frequency and high-frequency power. No significant relation was found in preadolescents. During standing, adolescents had a more marked increase in diastolic arterial pressure, heart rate, low frequency of R-R intervals, and low frequency of arterial pressure compared with those of preadolescents. Changes in diastolic pressure showed a significant negative correlation with changes in high frequency of R-R intervals.

CONCLUSION

Cardiovascular autonomic function plays an important role in increasing blood pressure levels associated with increased modulation of vagal tone of the heart after puberty but does not in the preadolescent.

Blood pressure responses in Japanese and Swedish children in the supine and standing position

We investigated the cardiovascular responses to active standing in Swedish and Japanese pre-pubertal children using non-invasive continuous beat-to-beat finger blood pressure (BP) monitoring. Seventy-eight Swedish (7-12 years) and 53 Japanese children (6-12 years) were examined. There were no significant differences in body weight or height between the two groups (total group). Finger blood pressure and heart rate were continuously recorded in the supine position and during standing. Supine BP was significantly higher in Swedish compared to Japanese children (115/65 vs 98/50 mmHg, P < 0.001), and Swedish children showed a significantly larger initial BP drop upon rising (-28/15 vs - 14/ -10 mmHg, P < 0.05) and a larger increment of heart rate (39 +/- 10 vs 29 +/- 8 beats. min-1, P < 0.05). There were, however, no differences in the blood pressure and heart rate changes in the following steady state period (2-3 min) between the two groups. These results suggest that Swedish pre-pubertal children have a higher basal blood pressure and enhanced cardiovascular autonomic responses, such as pronounced baroreflex receptor sensitivity and vasoconstrictor mechanisms. These differences in the two cohorts were not related to body dimensions or degree of maturation, indicating that autonomic functions in the cardiovascular system largely depend on genetic factors and environmental variables.