Bullous pemphigoid is associated with deposition of IgG and C3 at the dermal-epidermal junction. In order to see whether complement activation in bullous pemphigoid resulted in deposition of membrane attack complex (MAC) at the basement membrane zone, skin biopsies from patients with bullous pemphigoid were examined using a direct immunofluorescence technique. By employing a monoclonal antibody to a neoantigen of C9, the MAC was demonstrated in linear pattern at the basement membrane zone. These deposits were seen in both involved and uninvolved skin but the amount of MAC was greater in involved skin as judged by intensity of staining. Stippled deposits of MAC were also present in or around epidermal basal cells. The MAC could be generated in vitro by reaction of normal plasma with antibasement membrane antibody bound to sections of monkey esophagus. The IgG antibody activated complement and this complement activation proceeded all the way to the terminal step.
Bibliographical noteFunding Information:
Manuscript received August 1, 1983; accepted for publication September 21, 1983. Supported in part by grants from the National Institutes of Health (AI10704, AM25518, and AM26149). Dr. Ronald J. Falk is supported by USPHS T raining Grant AM07087. Reprint requests to: Mark V. Dahl, M.D., Depart ment of Dermatology, University of Minnesota, Box 98 University Hospitals, 420 Delaware Street S.E., Minneapolis, Minnesota 55455. Abbreviations: FITC: fluorescein isothiocyanate MAC: membrane attack complex PBS: phosphate-buffered saline VB: verona! buffer containing 4% bovine serum albumin