Periostin is a secreted extracellular matrix protein that has been shown to play an important role in the pathogenesis of allergic diseases, including both Th2 inflammation and tissue remodeling. It has been shown that the serum periostin level is a promising biomarker of allergic diseases in adults. However, little is known about the usefulness of this parameter as a biomarker for allergic diseases in childhood.
Methods
We recruited 304 elementary school-age children from an elementary school attached to Chiba University. The study protocol was approved by the Committee on Human Research of Chiba University. Informed consent was obtained from each of the study subjects and their guardians. The diagnosis of current bronchial asthma was made according to the ISSAC (International Study of Asthma and Allergies in Childhood) questionnaire. Concurrent physician-diagnosed atopic dermatitis, allergic rhinitis and food allergies were assessed. Children without any allergic diseases and those not exhibiting serum specific IgE to house dust mites, cedar pollen or egg whites were defined as “healthy children.” We recruited 204 adult volunteers without any allergic diseases as healthy adults. The serum periostin levels were measured using a sandwich enzyme-linked immunosorbent assay.
Results
Unexpectedly, we did not detect any increase in the serum periostin level in children with allergic diseases in comparison to healthy children. In addition, compared to that observed in the healthy adult controls, the serum periostin levels were significantly higher in the elementary school-age children, regardless of the presence or absence of allergic diseases.
Discussion
The serum level of periostin may be largely influenced by the rate of bone metabolism in childhood. Therefore, the high baseline level of serum periostin may mask any increase in the serum periostin level due to allergic diseases in childhood.
Conclusion
No increase in the serum periostin level was detected in elementary school-age children with allergic diseases, likely due to the high rate of bone turnover in this group. Further studies are needed to clarify the normal ranges of serum periostin at other ages (infancy and adolescence) and for which age groups the serum periostin level is a useful biomarker.