Distinguishing the antigen specificities of pemphigus vulgaris and pemphigus foliaceus using the biotin-avidin immunofluorescence method.

To compare the specificities of autoantibodies in sera from patients with pemphigus vulgaris (PV) and those with pemphigus foliaceus (PF), blocking-immunofluorescence studies were carried out using the biotin-avidin immunofluorescence technique. First cryostat sections of bovine muzzle epidermis were incubated with one of either the unlabeled PV or PF serum samples for 2 h at room temperature, then rinsed and overlayered for 30 min with serially diluted corresponding or other biotin-labeled PV (or PF) IgG fractions containing their autoantibodies. The sections were then incubated for 30 min in fluorescein-labeled avidin. The blocking abilities of PV (or PF) sera for the reaction of labeled PV (or PF) IgG on the membranous part of keratinocytes were compared. The following results were obtained: the titers of biotin-labeled PF IgG decreased considerably more in sections preincubated with PF sera than sections preincubated with PV or normal sera. The titers of biotin-labeled PV IgG decreased considerably more in sections preincubated with PV sera than sections preincubated with PF or normal sera. These results suggest that there may be a distinction in antigenic specificities between PV and PF sera.