PEMPHIGUS, AUTOIMMUNE-DISEASE OF EPIDERMA L-CELL ADHESION

Epidermal architecture is established and maintained through intercell ular junctions that allow cell-to-cell communication and transmit intr acellular organization to tissue structure. The main structures of coh esion between keratinocytes are desmosomes. Desmosomes are supramolecu lar assemblies of transmembrane glycoproteins that contribute to cell adhesion via their extracellular domains, and to plaque formation and intermediate filament coupling through their cytoplasmic tail. These d esmosomal glycoproteins belong to the cadherin superfamily of adhesion molecules and are the target of the autoimmune response in pemphigus. Pemphigus are a group of autoimmune bullous skin diseases resulting f rom a loss of epidermal cell-to-cell adhesion. The two main types of p emphigus include pemphigus vulgaris and pemphigus foliaceus. In pemphi gus vulgaris, the loss of adhesion occurs deep in the epidermis wherea s in pemphigus superficialis, the clivage is more superficial. Both fo rms of pemphigus are characterised by the presence of autoantibodies d irected to the desmosomal transmembrane glycoproteins. The pemphigus v ulgaris antigen (PVA) is the desmoglein 3 of MW 130 kDa, whereas the p emphigus foliaceus antigen is the desmoglein 1 of MW 160 kDa. Other de smosomal proteins, such as desmocollins and desmoplakins, are the targ et of autoantibodies in less frequent forms of pemphigus like IgA pemp higus and paraneoplastic pemphigus, respectively.