Although immunohistology is most commonly regarded by general pathologists as a technique that has its greatest application in neoplastic diseases, this conclusion is far from accurate in the the context of dermatopathology. In fact, diagnoses for many inflammatory skin disorders are largely predicated on the results of immunologic analyses. This has been true for more than 25 years.1 '
2The following presentation will briefly outline the methods used in non-neoplastic immunodermatopathology, with emphasis on reagents or techniques that have been introduced in the recent past. Because of spatial constraints and the easy availability of expansive reviews on several of the individual topics at hand, the following discourse will be confined to a concise and practical review of nonneoplastic immunodermatopathology. In that context, detailed consideration will not be given to clinical findings, conventional histologic features, or pathogenetic mechanisms attending the disorders encompassed here.
IMMUNOHISTOLOGIC METHODSSeveral immunohistochemical methods are applicable to inflammatory diseases of the skin, in addition to the traditional peroxidase-antiperoxidase or avidin-biotinperoxidase complex techniques. The most commonly used one is that of direct immunofluorescence (DIF) with a fluorescein isothiocyanate (FITC) label, 2 " 6 but indirect immunofluorescence (IIF) has also attained popularity, using monkey esophagus or human saline-split skin as substrates.3 " 5,7 " 10 In the first of these procedures, a biopsy of lesional skin is submitted promptly in saline, or, if sent