Single step multivariant analysis of serum autoantibodies in autoimmune blistering diseases using BIOCHIP® mosaic technology

A variety of immunoassays for the serological diagnosis of autoimmune bullous diseases has become available within the last decade and, subsequently, greatly facilitated the diagnosis of these disorders. However, a multistep diagnostic procedure is required for optimal diagnosis. Recently, by the use of the BIOCHIP technology, s single step assay has been developed that allows the simultaneous testing of different antigens and tissue substrates in a single incubation field. The novel assay is based on an indirect immunofluorescence microscopy employing a BIOCHIP mosaic that includes monkey esophagus, primate salt-split skin, antigen dots of tetrameric BP180-NC16A as well as desmoglein 1-, desmoglein 3-, and BP230gC-expressing human HEK293 cells. This BIOCHIP mosaic revealed sensitivities comparable with those of the corresponding ELISA systems and specificities ranged from 98.2% to 100% for all substrates. In a prospective study comparing the BIOCHIP mosaic to the standard multistep procedure, a high agreement was found for the diagnosis of bullous pemphigoid, pemphigus vulgaris, and pemphigus foliaceus as well as with sera without serum autoantibodies (Cohen between 0.88 and 0.97). Here, the use of the novel single-step multivalent assay is exemplified for the diagnosis of bullous pemphigoid and pemphigus vulgaris.