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. We sought to explore the range of periostin levels of children <2 years without significant confounding illnesses.

Methods: Children undergoing clinically indicated phlebotomy or having a peripheral intravenous catheter inserted prior to general anesthesia or procedural sedation were enrolled. A 0.5 mL sample of blood was collected and frozen at -70°C. After thawing, periostin was measured with a Luminex assay (R&D Systems, Minneapolis, MN). Medical record review and/or parental interview elicited potential variables associated with periostin. Association was evaluated using Mann-Whitney rank sum test, Kruskal-Wallis ANOVA, and Spearman correlation as appropriate.

Results: Among 43 children (23 male, 20 female, age range 9-15.7 months), periostin levels were inversely correlated to age (r = -0.438, P = 0.003). Periostin levels also differed significantly between children <12mo (734.0 [576.6-906.5] ng/mL), 12-18mo (645.1 [363.8-538.2] ng/mL) and >18mo (416.4 [363.8-538.15] ng/mL) (P < 0.001).

Conclusion: In our sample of relatively healthy patients <2 years old, periostin levels were inversely correlated with age and not dependent on other studied variables. However, further work is needed to establish normal periostin values in young children.