An important screening test for serum autoantibodies in pemphigoid diseases is indirect immunofluorescence on human salt-split skin. The majority of patients with pemphigoid diseases exhibit autoantibodies binding to the epidermal side of the artificial splits targeting mainly BP180, BP230 and α6β4 integrin. The remainder of patients (10%) with pemphigoid diseases display autoantibodies labelling the dermal side of the blister. In these patients, type VII collagen (epidermolysis bullosa acquisita), laminin 332 (anti-laminin 332 mucous membrane pemphigoid) and the 200 kDa p200 protein/laminin γ1 (anti-p200/ laminin γ1 pemphigoid) were identified as target antigens. The project focuses on a methodical research of the binding properties found within these patients, by using a new biochip which utilizes recombinant target antigens as a substrate in an indirect immunofluorescent based test. The new biochip mosaic contains HEK293 cells expressing the NC1-domain of type VII collagen, the laminin 332 heterotrimer and laminin γ1, respectively, on the cell surface to enable a serological analysis of the presented autoantibodies.

We will evaluate 400 sera of patients with autoantibodies binding to the blister floor, 200 consecutive sera from the serum bank of the dermatology clinic and 200 from a multicentre study with positive results in the direct immunofluorescence test. For the control group we will use 150 sera of patients with pemphigoid diseases who show epidermal binding properties, 50 sera of patients with pemphigus disease and 50 samples from healthy blood donors.