Use of Animal Skin Substrates for Indirect Immunofluorescence Diagnosis of Subepidermal Autoimmune Bullous Diseases

We read the article by Pang et al 1 concerning the use of frog skin for the differentiation of bullous pemphigoid (BP) from epidermolysis bullosa acquisita (EBA). Based on sporadic observations of a floor-pattern indirect immunofluorescence on 1 mol/L of sodium chloride—split skin (SSS) obtained from BP sera, these authors used skin from a toad to establish a differential diagnosis between BP and EBA. Their rationale was the fact that, as suggested by earlier studies, the BP antigen is present in the skin of some animals, 2 from which the EBA antigen—being phylogenetically more restricted—is absent. 3 Since this procedure seems attractive, we undertook a retrospective comparative study to better delineate the usefulness of animal skin substrates for the diagnosis, using indirect immunofluorescence, of subepidermal autoimmune bullous diseases. During the last 3 years, we screened over 1500 human serum samples sent to us under the suspicion of a subepidermal autoimmune