Expression of Integrins in Junctional and Dystrophic Epidermolysis Bullosa

Recently, monoclonal antibodies (MoAb) have been raised against a family of adhesive membrane receptors (R) for extracellular matrix molecules known as integrins. In order to ascertain whether these adhesive proteins are normally expressed in inherited epidermolysis bullosa (EB) dermal epidermal junction, we studied the reactivity of MoAb recognizing receptors for VLA-1 (R for unknown ligand), VLA-2 (R for collagen), VLA-3 (R for collagen, laminin, fibronectin), VLA-4 (R for unknown ligand), VLA-5 (R for fibronectin), VLA-6 (R for laminin), VNR alpha, and VNR beta (R for vitronectin) on cryostat skin sections from EB patients and normal controls and on cytospins of normal epidermal cell suspensions with indirect immunohistochemical methods. Two cases of junctional EB (EBj) (lethal and non-lethal), three cases of dominant dystrophic EB (EBdd), two cases of recessive dystrophic EB (EBdr), and two normal controls skin sections and cell suspensions entered the study. No significant modification of the distribution of these adhesive receptors was observed in junctional and dystrophic EB skin. Both in normal and EB specimens MoAb against VLA-2, VLA-3, and VNR alpha determinants showed reactivity with the total cytoplasmic membrane of basal keratinocytes and basement membrane zone. Interestingly, anti-VLA-6 MoAb was characterized by an intense linear staining of the dermal-epidermal junction with the same localization on the roof of the blisters in EBj, EBdd, and EBdr as bullous pemphigoid (BP) serum. On the basis of these results we suggest that anti-VLA-6 MoAb could be used instead of BP serum for immunohistochemical detection of the cleavage of blisters in EB.