A NOVEL IMMUNE-MEDIATED SUBEPIDERMAL BULLOUS DERMATOSIS CHARACTERIZED BY IGG AUTOANTIBODIES TO A LOWER LAMINA-LUCIDA COMPONENT

Background: Immune-mediated subepidermal bullous dermatoses characterized by in vivo-bound linear IgG deposition at the cutaneous basement membrane zone include bullous pemphigoid, ocular cicatricial pemphigoid, anti-bullous pemphigoid antigen mucosal pemphigoid, anti-epiligrin mucosal pemphigoid, epidermolysis bullosa acquisita, and the bullous eruption of systemic lupus erythematosus. In this article, we describe a novel IgG-mediated bullous dermatosis. Observations: Clinically, a unique nonscarring dermatosis was characterized by the sudden onset of extensive bullae and erosions on mucous membrane and skin, resembling toxic epidermal necrolysis or pemphigus vulgaris. Histologically, the patient's skin lesion demonstrated neutrophilic papillary dermal infiltration and subepidermal blister formation, resembling dermatitis herpetiformis. Immunopathologically, there was linear IgG and C3 deposition at the skin basement membrane zone. The patient responded well to prednisone and azathioprine immunosuppression and has achieved a lasting remission without further therapy. Further immunologic investigations revealed that this unique dermatosis is distinct from all other known IgG-mediated subepidermal bullous dermatoses. Conclusions: This novel deep lamina lucida pemphigoid can be distinctly termed anti-p105 pemphigoid on the basis of antigenic specificity of the autoantibodies. Although this novel dermatosis resembles toxic epidermal necrolysis clinically, prudent use of diagnostic immunofluorescence studies can clearly delineate its immunologic nature. Prompt recognition of this unique dermatosis and timely initiation of appropriate immunosuppressive therapy could be life-saving for those patients suffering from this dermatosis.