The molecular pathogenesis of bullous pemphigoid

The detection of immunopathologic abnormalities¹ prompted early studies that suggest that bullous pemphigoid is mediated by antibody-dependent complement activation following initiation by an epidermal basement membrane zone antigen.² These concepts will not be further considered in this chapter but are reviewed elsewhere (chapter 12) in this volume.Study of the molecular pathogenesis of bullous pemphigoid has been aided by the ease of recognition of each clinical stage in lesional development and by easy access to a complex biologic fluid formed during the inflammatory process.³ Specimens of lesions at each stage of development from patients were examined for histologic changes by the 1-μm-thick section technique⁴ and for immunopathologic abnormalities by direct immunofluorescence. In a single patient, lesions at each stage of development have been examined with the electron microscope for ultrastructural alterations.⁵ These studies permitted appreciation of the sequence of pathologic events that must be considered in understanding the molecular pathogenesis of bullous pemphigoid.This chapter considers the pathologic events that characterize the tissue damage observed in bullous pemphigoid. In addition, the potential molecular contribution of cells that participate in the mediation of the inflammatory events characteristic of this unique bullous disease are examined.