All of the following are immunologically mediated blistering diseases except: September 2010

Ans. D: Psoriasis Classification of the blister-forming autoimmune skin diseases is based on the localization of the blister formation. The diseases can mainly be categorized into two common groups: Pemphigus - exhibit an intra-epidermal loss of adhesion Pemphigoid - exhibit an sub-epidermal loss of adhesion In pemphigoid, IgG antibodies bind to basement membrane zone components and affects all stratified squamous epithelial mucous membranes.Blistering occurs in a subepidermal location, which is caused by loss of adhesion between the basal keratinocytes and dermis There are two main types of pemphigoid: bullous pemphigoid (BP) and cicatricial pemphigoid(CP). BP is the most common subtype and involves blisters below the surface of the skin, but can also affect mucous membranes. CP most commonly affects the mucous membrane in the body In Bullous Pemphigoid, autoantibodies are directed against the normal components of hemidesmosomes, BP180 and BP230. Detection of circulating IgG basement membrane zone antibodies, along with their basement membrane zone localization, can be used as sensitive and specific diagnostic tests for pemphigoid.