The British journal of dermatology
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Basement membrane components and collagen biosynthesis were studied in suction blisters in human skin. The basement membrane components were characterized by immunofluorescence using specific antibodies to type IV collagen, laminin and fibronectin, and collagen biosynthesis was studied by assaying galactosylhydroxylysyl glucosylatransferase. In suction blisters, the separation of epidermis and dermis occurred above the lamina lucida, indicating that the basement membrane, composed of lamina lucida and lamina densa, forms a mechanically strong entity. ⋯ Galactosylhydroxylysyl glucosyltransferase activity could be demonstrated in blister fluid and was about the same as in serum when expressed on the basis of protein in fresh blisters. It increased by 2-3 fold during the repair of blisters, indicating that there was local production of this enzyme. Further studies revealed that pure epidermis contained galactosylyhdroxylysyl glucosyltransferase and hydroxyprolineand this suggests that epidermis may synthesize some collagen type which, according to these studies, is not type IV (basement memebrane) collagen.
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Purified antibodies against type IV collagen and laminin were used ot localize basement membranes by indirect immunofluorescence in various anatomical regions of normal and diseased human skin. The two proteins showed extensive codistribution. A continuous linear staining was found along the epidermal-dermal junction and around hair follicles, sebaceous gland acini and small capillaries. ⋯ Blister formation in bullous pemphigoi left type IV collagen and laminin on the floor of the blister, while the bullous pemphigoid antigen as detected by human autoantibodies was found on both sides of the blister. In solid basal cell carcinoma a strong staining was found around all tumour islands as well as focally within the cell clusters. This suggests that the tumour cells produce these basement membrane proteins but have lost, at least in part, control of polar deposition.