Periostin levels in children without respiratory disease.

Background: Periostin is a protein that serves as a downstream marker of the T-helper type 2 (Th2) cell response. It may serve to identify drug-responsive inflammatory phenotypes, particularly in children with asthma and possibly bronchiolitis. There are no published levels of periostin in healthy children <2 years of age, limiting interpretation of periostin levels in disease.