Blister formation in inflamed lesions of bullous pemphigoid were studied by electron
microscopy. Three stages can be distinguished during the development of a blister:(1) There
is marked edema in the dermis and epidermis and a rather pronounced cellular infiltrate in
the dermis. Projections of basal cells are in contact with infiltrate cells.(2) The basal lamina
shows discontinuities. Eosinophilic leukocytes migrate into the epidermis and
degranulate.(3) In the fully developed blister the basal lamina is usually absent. Our findings …