ULTRASTRUCTURAL-LOCALIZATION OF PEMPHIGUS -VULGARIS AND PEMPHIGUS FOLIACEUS ANTIGENS BY INDIRECT IMMUNOELECTRON MICROSCOPY (7 CASES)

Introduction. Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune blistering diseases characterized by loss of cell-cell adh esion and by autoantibodies directed against epidermal cadherins. The ultrastructural localization of PV antigen remains controversial, wher eas the location of PF antigen seems to be established. The use of dif ferent techniques could explain these various data. To investigate thi s matter, indirect immunoelectron microscopy (IEM) and Western blot an alysis on bovine tongue epithelium were used. Material and method. Ser um samples from patients with PF (3), PV (4) and control samples from healthy patients (2) were analysed in this study. The inclusion criter ia were based upon characteristic clinical features, level of epiderma l cleavage on histological preparations and presence of circulating an ti-epithelial cell surface antibodies. Indirect IME was performed on n ormal human skin. Peroxidase Labelling was used. Serum samples were al so analysed by western immunoblotting on bovine tongue epithelium. Res ults. Indirect IEM examination of PV sera showed immune deposits locat ed both on desmosomal and extra-desmosomal areas, whereas in PF, IgG d eposits were strictly localized on desmosomal structures; fly Western blot analysis, PV sera recognized a 130 kDa polypeptide and PF sera a 150 kDa polypeptide. Discussion. Indirect IEM on normal human skin usi ng peroxidase labelling was used because of the best antigenic conserv ation obtained. Our results suggest that PV antigen could exist both o n desmosomal junctions and adherens junctions, whereas PF antigen (des moglein I) is restricted to desmosome.