title: LAD-1 is absent in a subset of junctional epidermolysis bullosa patients.
abstract: The anchoring filament protein LAD-1 has been recently identified as the target of autoantibodies in the acquired blistering disorder linear IgA bullous dermatosis. Because this protein appears to be involved in the process of dermal-epidermal cohesion, this study sought to determine the involvement of LAD-1 in the pathology of junctional epidermolysis bullosa (JEB). To this end, 44 patients with a variety of subtypes of JEB were analyzed by indirect immunofluorescence microscopy with antibodies to LAD-1, BP180, and laminin-5. We found that only patients with generalized atrophic benign epidermolysis bullosa (GABEB) contained LAD-1 defects. Of the 16 GABEB patients studied, 13 showed absent or greatly reduced expression of LAD-1 (including 2 patients with a peculiar interrupted staining pattern) and 3 patients showed defects of laminin-5 expression with normal LAD-1 expression. Patients who showed LAD-1 defects also showed abnormal expression of BP180. Keratinocytes were cultured from the skin of two GABEB patients and analyzed by indirect immunofluorescent microscopy. One culture demonstrated defects of BP180 and LAD-1 expression (which was also verified by radioimmunoprecipitation assay), and one culture showed decreased laminin-5 expression but normal BP180 and LAD-1 expression. Thus, these studies demonstrate that: (i) LAD-1 and BP180 are normally expressed in all subtypes of JEB except GABEB, (ii) the majority of GABEB patients show absent or near absent expression of both LAD-1 and BP180 but normal expression of laminin-5, and (iii) a smaller subset of GABEB patients show normal LAD-1 and BP180 expression but express persistent but reduced levels of laminin-5.
authors.affiliation: Veterans Administration Palo Alto Health Care System, and Department of Dermatology at Stanford University School of Medicine, California 94305, U.S.A.
authors.forename: M P
authors.initials: MP
authors.lastname: Marinkovich
authors.forename: H H
authors.initials: HH
authors.lastname: Tran
authors.forename: S K
authors.initials: SK
authors.lastname: Rao
authors.forename: G J
authors.initials: GJ
authors.lastname: Giudice
authors.forename: S
authors.initials: S
authors.lastname: Balding
authors.forename: M F
authors.initials: MF
authors.lastname: Jonkman
authors.forename: H H
authors.initials: HH
authors.lastname: Pas
authors.forename: J S
authors.initials: JS
authors.lastname: McGuire
authors.forename: G S
authors.initials: GS
authors.lastname: Herron
authors.forename: L
authors.initials: L
authors.lastname: Bruckner-Tuderman
mesh_terms: D001323:Autoantibodies / Q000235:genetics; D001324:Autoantigens / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000276:immunology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016109:Epidermolysis Bullosa, Junctional / Q000378:metabolism* / Q000473:pathology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015603:Keratinocytes / Q000473:pathology; D008840:Microfilament Proteins / Q000276:immunology; D024041:Non-Fibrillar Collagens; D011233:Precipitin Tests; D011863:Radioimmunoassay; D012867:Skin / Q000473:pathology; D000097794:Kalinin; D000097805:Collagen Type XVII
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015815:Cell Adhesion Molecules; D017077:Culture Media, Conditioned; D008840:Microfilament Proteins; D024041:Non-Fibrillar Collagens; D000097794:Kalinin; D000097805:Collagen Type XVII