Fig. (1).

Immunohistochemistry of a representative section of the airway of a non-asthma control, a patient with mild-to-moderate asthma, and a patient with asthma who died of status asthmaticus (as indicated). The asthmatic airway demonstrates typical thickening of the basement membrane (1), and the characteristic increased mass of smooth muscle cells (2) [Reprinted with permission of the American Thoracic Society. Copyright (c) American Thoracic Society. Borger P, Tamm M, Black JL, Roth M. Asthma: is it due to an abnormal airway smooth muscle cell? Am J Respir Crit Care Med. 2006 Aug 15; 174 (4): 367-72; Official Journal of the American Thoracic Society, Diane Gern, Publisher].