Expression of the alpha 6 beta 4 integrin in lesional skin differentiates bullous pemphigoid (BP) from epidermolysis bullosa acquisita (EBA)

The integrin alpha 6 beta 4 complex is a protein of the membrane of basal keratinocytes, localized at the surface of cells in contact with the basement membrane zone in normal skin. The expression of alpha 6 beta 4 was investigated in several autoimmune blistering skin diseases including bullous pemphigoid (BP), epidermolysis bullosa acquisita (EBA), bullous systemic lupus erythematosus (BSLE), and pemphigus vulgaris (PV) by an indirect immunofluorescence technique. In lesional bullous skin of BP, alpha 6 beta 4 expression was either absent, or in some cases represented an unusual irregular patchy staining. In contrast, in lesional bullous skin from EBA, BSLE, and PV, alpha 6 beta 4 expression was comparable to that observed in normal skin, i.e., a linear staining of the BMZ. Thus, analysis of the alpha 6 beta 4 integrin reactivity on lesional skin, in conjunction with the typical localization of collagen IV, allows a rapid and accurate distinction between BP and EBA.