Monoclonal Antibodies to Anchoring Fibrils for the Diagnosis of Epidermolysis Bullosa

Murine monoclonal antibodies to human anchoring fibrils reacted with human and monkey cervix, tongue, esophagus, and vagina. Rat, mouse, and guinea pig tissues were negative. In 11 patients with dystrophic recessive epidermolysis bullosa there was no reaction by immunofluorescence and immunoelectron microscopy. Other forms of epidermolysis bullosa had normal reactivity

Epidermolysis Bullosa Dystrophica-Recessive: A Possible Role Of Anchoring Fibrils In The Pathogenesis

The purpose of this study was to define the ultrastructural defects and pathogenesis of epidermolysis bullosa dystrophica-recessive (EBD-R). The only consistent ultrastructural alteration found in EBD-R was an absence of anchoring fibrils. In many specimens of nonblistered, nontraumatized EBD-R skin, absence of anchoring fibrils was the only ultrastructural abnormality observed. The possibility that lack of anchoring fibrils was a secondary change resulting from previous blistering and scarring was eliminated by our observation that anchoring fibrils were consistently absent in the never previously blistered skin of two newborns with EBD-R. In experimentally traumatized skin, the epidermis and dermis separated in the region of the epidermal-dermal junction normally occupied by anchoring fibrils. Basal lamina and dermal microfibril bundles appeared to be normal. Using recombinant grafts, we demonstrated that anchoring fibrils were not formed by EBD-R dermis when combined with EBD-R epidermis or normal epidermis. Anchoring fibrils were formed when normal dermis was combined with normal and EBDR epidermis. These studies indicate that the defect in EBD-R resides in the dermis and that the defect may he associated with impaired formation of anchoring fibrils

Epidermal-dermal Interactions in Adult Skin

Epidermal-dermal interactions are important determinants of embryonic development in skin. This review examines the role of such epidermal-dermal interactions in the conservation of epithelial specificity in adult skin. The basic epidermal keratinization program as defined as a proliferative basal cell population, orderly stratified cytodifferentiation of the cells and production of stratum corneum can be expressed by adult epidermis without the continued presence of a specific dermis. This is evidenced by the ability of epidermis to differentiate fully in association with nondermal connective tissues. Several other epithelia including cornea and esophagus express their specific differentiative characteristics without the continued presence of specific connective tissue. On the other hand, certain regional epithelial specificities in adult skin may be determined by the dermis. These regional epidermal specificities involve alterations in epidermal thickness, size of epidermal compartments including the stratum corneum, and the folding pattern at the epidermal-dermal interface. Possible mechanisms by which dermis could control these regional characteristics are discussed. Epidermal-dermal recombination techniques have been used to define the site of gene action in a variety of inherited skin abnormalities in animals. Similar studies are reported utilizing adult human skin in long-term cultivation on nude athymic mice. The abnormal gene in lamellar ichthyosis exerts its effect directly on the epidermis. Generalized exfoliative psoriasis was also studied by recombination techniques. Both epidermis and dermis were required for the maintenance of psoriatic morphology, suggesting a complex polygenic mechanism or one involving both genetic and environmental factors

Functional Heterogeneity of Immune Complexes in Epidermolysis Bullosa Acquisita

Epidermolysis bullosa acquisita is an inflammatory subepidermal bullous disease characterized by circulating and tissue-bound complement-binding anti-basement membrane zone autoantibodies to type VII procollagen. Lesions are characterized by neutrophil-predominant inflammation in some patients, but not in others. These features suggest complement activation and generation of complement-derived chemotactic factors for leukocytes by basement membrane zone immune complexes may contribute to inflammation, but that complexes may be heterogeneous in the ability to express that function. In this study, we measured the ability of basement membrane zone complexes from patients with (n = 4) and without (n = 6) neutrophil predominant inflammation to activate complement and generate complement-derived chemotactic activity using a complement-dependent neutrophil attachment assay. The results showed considerable heterogeneity in neutrophil attachment among EBA patients and that both the incidence (4/4 vs 2/6) and magnitude (81 +/- 34 vs 12 +/- 10 neutrophils/mm basement membrane zone) of attachment were greater in patients with neutrophil-predominant inflammation. Functional heterogeneity appeared to be due to differences in the amounts of complement-activating complexes formed at the basement membrane zone, which in turn appeared to be due to differences in the availability of circulating complement-binding anti-basement membrane zone antibodies. This was suggested by a positive correlation (r = 0.72, p less than 0.01) between neutrophil attachment and complement-binding anti-basement membrane zone antibody titers and the observation that high levels of neutrophil attachment could be generated in skin from patients with epidermolysis bullosa acquisita who did not have neutrophil-predominant inflammation by treating their skin in vitro with complement-binding anti-basement membrane zone antibodies. These results suggest tissue complexes in epidermolysis bullosa acquisita are heterogeneous in the ability to activate complement and generate complement-derived chemotactins (C5a, C5a des arg), and that functional heterogeneity contributes to histologic heterogeneity. The functional immunologic-pathologic correlations observed in this study suggest epidermolysis bullosa acquisita is an autoimmune "collagen" disease

Differentiating Anti-Lamina Lucida and Anti-Sublamina Densa Anti-BMZ Antibodies by Indirect Immunofluorescence on 1.0 M Sodium Chloride-Separated Skin

L'immunofluorescence indirecte sur la peau séparée est une méthode fiable pour différencier les anticorps contre la lame transparente et les anticorps contre la sous-lame dense des maladies bulleuses et la différenciation entre les anticorps est essentielle pour un diagnostic exact chez certains malades. Les anticorps contre la lame transparente dans la pemphigoïde bulleuse peuvent présenter plusieurs spécificités

Increased Frequency of HLA-DR2 in Patients with Autoantibodies to Epidermolysis Bullosa Acquisita Antigen: Evidence that the Expression of Autoimmunity to Type VII Collagen Is HLA Class II Allele Associated

Epidermolysis bullosa acquisita (EBA) is a chronic blistering disease characterized by circulating and tissue bound IgG auto-antibodies to the basement membrane zone (BMZ) of stratified squamous epithelium. Recent studies have shown that antibodies recognize epitopes present in the noncollagenous carboxyl-terminal domain of type VII collagen, a BMZ matrix protein. Antibodies with identical specificity also have been detected in patients with the rare blistering disease, bullous systemic lupus erythematosus (bullous SLE), suggesting EBA and bullous SLE are immunologically related diseases. In this study we determined the major histo-compatibility antigen types of 29 EBA patients and 6 patients with bullous SLE. Analysis of the results showed HLA-DR2 was significantly increased in both black EBA patients, P = 0.013 (corrected, RR = 4.8) and whit EBA patients, P = 0.0008 (corrected, RR = 13.1). Five of the six bullous SLE patients also were positive for the DR2 antigen, P = 0.009. These results show the expression of autoimmunity to type VII collagen is HLA class II allele associated and that EBA and bullous SLE are immunogentically related diseases

Absence of Specific Histologic Changes in Guinea Pig Skin Treated With Bullous Pemphigoid Antibodies

Previous studies have reported that intradermal injections of bullous pemphigoid antibodies into guinea pigs can reproduce the histologic and immunohistologic features of bullous pemphigoid lesions. In this study we examined this model to determine its reproducibility and suitability for testing other types of anti-BMZ antibodies. Twenty guinea pigs were injected intradermally with 0.1, 0.3, or 0.5 ml of either bullous pemphigoid serum or IgG fraction containing high-titer complement-binding anti-BMZ antibodies or an equivalent volume of normal human serum or IgG fraction as control. Sites were biopsied at intervals after injection and were examined by routine histology and direct immunofluorescence. The results showed (a) no difference in the incidence of dermal epidermal separation or type of inflammation in experimental and control sites; (b) no evidence of an eosinophil-rich inflammatory reaction typical of bullous pemphigoid; (c) an absence of linear BMZ deposits of IgG and complement in the majority of sites injected with bullous pemphigoid antibodies; and (d) no correlation between dermal-epidermal separation and deposition of immune reactants at the BMZ. These results suggest the histologic changes seen in guinea pigs that are administered intradermal injections of bullous pemphigoid antibodies are nonspecific and that the model is not suitable for testing the pathogenicity of anti-BMZ antibodies in sera or IgG fractions

The Epidermal-Dermal Junction

Ultrastructurally, the epidermal-dermal junction is composed of four component areas: (1) the basal cell plasma membrane with its specialized attachment devices or hemidesmosomes, (2) an electron-lucent area, the lamina lucida, (3) the basal lamina, and (4) the sub-basal lamina fibrous components, including anchoring fibrils, dermal microfibril bundles, and collagen fibers. The light microscopic “basement membrane” comprises only the sub-basal lamina fibrous zone. Other cell types, including melanocytes and Merkel cells, are also found at the epidermal-dermal junction. Structures at the junction derive their origin from the epidermis and dermis: the basal lamina is primarily of epidermal origin, the anchoring fibrils of dermal origin. The junction serves the following functions: (1) epidermal-dermal adherence, (2) mechanical support for the epidermis, and (3) a barrier to the exchange of cells and of some large molecules across the junction