Histopathologic features of early and progressive asthma

During the last decade, morphologic studies on bronchial biopsy specimens h ave led to our present understanding of asthma as an inflammatory airways d isease, However, little knowledge exists about the sequence of cellular eve nts during the disease or of possible mucosal changes early in asthma, So f ar the primary cause, the site of damage, and the mechanisms inducing the i nflammatory reaction remain to be elucidated. A multifactorial genetic susc eptibility may be important for the development of asthma, Suggested factor s that may trigger changes in the cells' morphologic and functional phenoty pe are viral infections, allergen exposure, maternal factors, diet, and smo king, Current evidence has implied that interactions between epithelial cel ls and the subepithelial connective tissue in the mucosa are important for normal homeostatic balance. Changes in airway epithelial phenotype possibly resulting from altered gene expression in its lining cells may be very imp ortant even as a first line change in asthma.