There is plexiform deposition of immunoglobulins, collagen I and III, tenascin and fibronectin; there is no evidence of laminin deposition.2, 8 These proteins are produced by activated myofibroblasts, which leads to subepithelial fibrosis.2, 9 Thickening of the basement membrane was not related to the severity, duration or etiology of asthma in some studies;10 others, however, have reported a correlation between these findings and disease severity.11 Here, FN1 is linked to asthma.