〔 Original Paper〕 Age-related changes in allergic symptoms and serum TARC concentration in school children

Background Thymus and activation-regulated chemokine （TARC ） is a Th2-related chemokine that is associated with allergic diseases. We investigated growth-related changes in allergic symptoms and TARC concentration in serum during later childhood to examine how Th2-related factors are associated with allergic symptoms. Methods This study was performed in 146 school children living in a suburban Japanese city. At the 1st grade in 1997 and the 5th grade in 2001, these children underwent question-naire investigation on respiratory and allergic symptoms and blood collection for determining total IgE, mite IgE and TARC concentrations in serum. Results TARC concentration in serum significantly decreased at the 5th grade （424.1 pg/mL ） compared with at the 1st grade （489.2 pg/mL ） in the entire child population. In children with no allergic symptom at either grade, serum TARC concentration was signifi-cantly decreased at the 5th grade （410.7 pg/mL ） compared with at the 1st grade （521.4 pg/ mL）, while there was no decrease in the serum concentration of TARC in allergic children at either or both of the two grades. There was also a difference in the decrease of serum TARC concentration at the 5th grade according to total IgE and mite IgE in addition, the presence o