Abstract: In order to investigate the relationship between lichen planus pemphigoides (LPP) and bullous pemphigoid (BP) and to determine whether the LPP antigen is the classical BP antigen. Four LP patients who were found to have blisters or subepidermal bullae by clinical and histopathological findings were investigated using DIF, IIF, immunoblotting methods. The results showed that there were linear deposition of IgG along the BMZ in three cases, C3 granular deposition in four cases, and linear fibrin deposition in 3 cases. Two out of these patients showed circulating IgG anti-BMZ antibody with titers 1:80 and 1:320, and lmol/L NaCl split section showed that the antibody was bound to the epidermal side, as did control BP antisera. Western blotting of the epidermal extracts using the sera of these 4 patients showed that all 4 patients'sera reacted with the epidermal antigen, and the sera of 2 patients reacted with 200kD antigen which is different from classical bullous pemphigoid antigen. With a review of literature we suggest that LPP is not the overlapping of BP and LP.

Key words: Lichen planus, Pemphigoides