To the Editor.—
We read with interest the article in the September 1985 issue of the Archives by Goldberg et al1 concerning the best substrate for bullous pemphigoid (BP) antibodies. Our group completed a similar study in late 1985 that compared BP antibody titers from various skin sites on a monkey with BP antibody titers achieved on monkey esophagus. Skin was obtained from a living monkey and prepared for indirect immunofluorescence in the standard manner.2 Skin sites included face, chest, abdomen, buccal mucosa, and flexor and extensor arm and leg. Human sera from three patients with BP with titers on monkey esophagus of 640, 1,280, and 1,280, respectively, were studied. Skin sites from all areas showed poor staining, all titers being less than 60. Skin taken from the oral mucosa and extremities showed the highest titers, and no statistical difference between samples of skin taken from flexor and extensor