The distribution of α6β4 integrins in lesional and non-lesional skin in bullous pemphigoid

The alpha 6 beta 4 integrin is associated ultrastructurally with the hemidesmosomes of the basal keratinocytes and with the bullous pemphigoid antigen (BPA), suggesting an important role in adhesion of epidermal cells to the basement membrane. Using an immunofluorescence technique with chain-specific monoclonal antibodies to the alpha and beta subunits we have investigated the distribution of the alpha 6 beta 4 integrin in normal skin (n = 3) and in BP skin (uninvolved, perilesional and lesional) n = 11]). The findings have been compared with other types of subepidermal blisters and with normal skin split by chemical means (n = 2) and by suction (n = 2). The distribution of alpha 6 beta 4 integrin was compared with that of bullous pemphigoid antigen (BPA) and with other basement membrane zone (BMZ) macromolecules, laminin, collagen type IV, collagen type VII and the BM600 antigen. In uninvolved, perilesional and early pre-blistered lesional BP skin the distribution of both the alpha 6 and beta 4 integrin subunits, BPA laminin, collagen types IV and VII and the BM600 antigen was identical to normal skin, i.e. a linear band in the BMZ. Within BP blisters, both alpha 6 and beta 4 integrin subunits and BPA were absent, except in two blisters in which the integrin expression was retained in the blister roof, despite loss of BPA. The other BMZ components were expressed on the blister floor.(ABSTRACT TRUNCATED AT 250 WORDS)