[The basement membrane and its significance in congenital and acquired diseases of the skin].

Basal membranes are an ubiquitous component of all human organs and fulfil a large variety of functions. They separate epithelial from mesenchymal tissue and control the passage of substances, of inflammatory as well as tumor cells. They form the extracellular cytoskeleton, regulate growth processes, and play an important part in wound healing. Ultrastructurally, the lamina densa can be distinguished from the lamina lucida. Anchoring fibrils connect the basal membrane of the dermoepidermal junction with the underlying dermis, while anchoring plates connect it with the epidermal cells. During the last few years, various components of the basal membrane have been biochemically analyzed. Different proteins were characterized, and their corresponding morphological structure could be identified. The growing knowledge regarding the structure and composition of the dermo-epidermal junction has led to a better understanding of many diseases involving this structure, in particular inborn and acquired bullous diseases, but also that of the role of the basal membrane in metastasis and tumor invasions. The characterization of antigens in bullous diseases with circulating antibodies has led to exact diagnostic criteria concerning the often overlapping disorders and allows, e.g., the differentiation between bullous pemphigoid and epidermolysis bullosa acquisita.