FN1 and asthma: In patients with asthma, periostin is upregulated and co-localizes with other proteins of the basement membrane such as tenascin-C, collagens I, III, and IV and fibronectin (174, 307), and correlates with “Th2-high” asthma, characterized by high expression of cytokines IL-13 and IL-5 (308, 175).