Localization of bullous pemphigoid antibody--an indirect immunofluorescence study of 228 cases using a split-skin technique.

We have re-examined the site of deposition of IgG anti-basement membrane zone antibodies in 228 sera from suspected cases of bullous pemphigoid (BP), using 1.0 M sodium chloride split-skin as substrate for indirect immunofluorescence. Nine sera (4%) produced fluorescence on the floor of the split suggesting sub-basal lamina antibody deposition compatible with a diagnosis of epidermolysis bullosa acquisita (EBA). This ultrastructural localization was confirmed in only three of these nine by immuno-electron microscopy. Clinical details were available on six of these nine cases, and none had clinical features suggesting EBA. We have found the split-skin immunofluorescence technique unhelpful in identifying 'missed' cases of EBA. The prevalence of EBA presenting as BP would appear to be very low indeed in the U.K.