309 A utoimmune bullous diseases encompass a group of blistering diseases characterized by the presence of autoantibodies that are found both in the circulation and bound in vivo to perile- sional epithelial tissues. They are generally classified into 2 categories, based on the location of blister for- mation. In the pemphigus group, blisters occur with- in the epidermis, and in the group of subepidermal blistering diseases, the lesions occur just below the epidermis. 1 Within each of these groups, multiple, distinct clinical entities have been defined based on clinical, histologic, and immunofluorescence (IF) findings. 2 More recently, biochemical and molecular biologic approaches have revealed the identity of the target antigens in several of the bullous diseases. 2 With the advent of these new techniques, it has also been possible to describe and characterize new blis- tering diseases with novel immunologic features. In this report, we describe a patient with an autoim- mune subepidermal bullous disease associated with IgG autoantibodies to a 200 kd dermal protein that has recently been reported as a novel autoantigen of the lower lamina lucida of the basement membrane zone (BMZ). 3-6 CASE REPORT In December 1996, a consultation was required for an 81-year-old white man with a bullous eruption that had first appeared 2 weeks earlier. Past medical history was relevant for an adult-onset diabetes mel- litus treated with glibenclamide, hypertension treat- ed with enalapril, congestive heart failure treated with furosemide, and hypercholesterolemia treated with cholestyramine. Cutaneous examination revealed the presence of tense vesicles and numer- ous erosions on the dorsum of the hands, as well as on forearms and knees (Fig 1). The remaining skin and mucous membranes were unaffected. Histologic examination of a lesional skin biopsy specimen showed an area of dermal-epidermal sepa- ration and dermal inflammatory infiltrates mainly consisting of neutrophils. Eosinophils and mononu- clear cells were less frequent. Neutrophilic microab- A subepidermal bullous eruption associated with IgG autoantibodies to a 200 kd dermal antigen: The first case report from the United States José M. Mascaró Jr, MD, a,c Detlef Zillikens, MD, a,d George J. Giudice, PhD, a,b Fréderic Caux, MD, a Matthew G. Fleming, MD, a Henry M. Katz, MD, e and Luis A. Diaz, MD a Milwaukee, Wisconsin; Barcelona, Spain; Würzburg, Germany; and Manitowoc, Wisconsin We describe an 81-year-old white man in whom a subepidermal bullous eruption developed that clinically resembled bullous pemphigoid. The eruption promptly responded to oral tetracycline and niacinamide and topical clobetasol. Histologic examination of perilesional skin revealed neutrophilic infiltration with formation of papillary microabscesses and subepidermal cleavage. Direct immunofluorescence showed linear deposition of IgG and C3 along the basement membrane zone. By indirect immunofluorescence, circulating IgG autoantibodies bound exclusively to the dermal side of salt-split normal human skin. Immunoblot analysis demonstrated that the patient’s autoantibodies reacted with a 200 kd dermal protein that was different from type VII collagen, the epidermolysis bullosa acquisita autoantigen. This patient represents the first confirmed case from the United States with a recently reported novel autoimmune subepidermal bullous disease associated with IgG autoantibodies to a 200 kd dermal antigen. (J Am Acad Dermatol 2000;42:309-15.) This supplement is made possible through an educational grant from Ortho Dermatological to the American Academy of Dermatology. From the Departments of Dermatology a and Biochemistry, b Medical College of Wisconsin, Milwaukee; the Department of Dermatology, Hospital Clinic, Barcelona; c the Department of Dermatology, University of Würzburg; d in private practice in Manitowoc. e Reprint requests: Luis A. Diaz, MD, Department of Dermatology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee,WI 53226.E-mail:ldiaz@med.unc.edu Copyright © 2000 by the American Academy of Dermatology,Inc. 0190-9622/2000/$12.00 + 0 16/4/98954