ALTERED EXPRESSION OF EPITHELIAL INTEGRINS AND EXTRACELLULAR-MATRIX RECEPTORS IN ORAL ERYTHEMA MULTIFORME

Inflammation and ulceration at the epithelium-connective tissue interf ace, a characteristic of erythema multiforme (EM), may be associated w ith altered molecular attachment of basal keratinocytes. To determine the expression of basal keratinocyte-associated integrins and their ba sement membrane ligands in oral EM, specimens of clinically and micros copically confirmed EM (n=12) and mucosal controls (n=7) were stained immunohistochemically for the integrins alpha 3, beta 6, beta 1, and b eta 4 and for extracellular matrix proteins laminin 1, laminin 5, coll agen IV, and collagen VII using a standard avidin-biotin-peroxidase te chnique. In EM, results showed increased staining intensity for all in tegrins studied in basal and suprabasal keratinocytes. Basement membra ne-associated staining of a6 and b4 was intense, but disrupted and fra gmented. In EM, integrin staining was most marked at the summit of the connective tissue papillae. Laminin 5 staining was more intense than in controls, Tvas frequently fragmented, and extended into the lamina propria. Laminin 1 staining was discontinuous and was frequently less intense than in controls. Collagen IV staining in EM was interrupted a long the basement membrane. Collagen VII staining was fragmented but u nchanged in intensity. These alterations in interface adhesion molecul es suggest that hemidesmosome-associated molecules are important in th e pathogenesis of EM. The staining intensities and patterns of express ion of these adhesion molecules suggest that oral EM is initially focu sed in the connective tissue papillae. (C) Munksgaard 1996.