Serum and blister fluid anticomplementary activity in pemphigus and bullous pemphigoid. Sucrose density gradient...

By sucrose density gradient ultracentrifugation and standard hemolytic complement assays, complement fixing activity of about 19 S and greater was found in blister fluids of one patient with pemphigus and three of five patients with bullous pemphigoid. Control blister fluids, including experimentally induced blisters, lacked such activity. Complement fixing activity was apparent, however, in 6 of 10 pemphigus sera and in two of five bullous pemphigoid sera tested. The material present in both pemphigus and bullous pemphigoid appears to activate the classical complement pathway.