POSTN and esophagitis: Given that previous studies have demonstrated that periostin also plays a critical role in the trafficking, activation, and cytokine release of leukocytes [39, 40], these findings suggest that periostin contributes to esophagitis, and periostin may directly regulate leukocyte (eosinophil) accumulation in T helper type 2-associated mucosal inflammation in both mice and humans [18].