Passive transfer of autoantibodies from a patient with mutilating epidermolysis bullosa acquisita induces specific alterations in the skin of neonatal mice.

BACKGROUND: Epidermolysis bullosa acquisita is a subepidermal bullous disease characterized by IgG autoantibodies directed against type VII collagen in anchoring fibrils. These autoantibodies are believed to play an important role in the pathogenesis of sub-lamina densa blister formation in this disease. OBSERVATIONS: We describe a patient with epidermolysis bullosa acquisita who has developed mutilating acral involvement with early syndactyly and extensive scarring lesions of the scalp. The patient's serum contains IgG autoantibodies that bind the dermal side of 1-mol/L sodium chloride-separated human skin (at a titer up to 5120), as determined by indirect immunofluorescence microscopy, and type VII collagen, as determined by immunoblot. The severity of this patient's disease and the height of his immune response to type VII collagen prompted us to assess the pathogenicity of his autoantibodies in a murine model. Purified IgG from our patient (or that from a healthy volunteer who served as a control) was administered subcutaneously to BALB/c mice (10 mg/g of body weight) on 2 consecutive days. Light microscopy of normal-appearing skin showed pronounced dermal edema and a dense granulocyte-rich infiltrate in the superficial dermis. Deposits of human IgG, murine C3, and the membrane attack complex of complement were found in the epidermal basement membrane of all experimental mice. Immunogold electron microscopy demonstrated that deposits of human IgG in an experimental subject were localized to anchoring fibrils. Serum samples from mice receiving IgG antibodies from our patient had high titers of circulating antibodies directed against the dermal side of 1-mol/L sodium chloride-separated human skin (titer, 640 to 1280). Light, immunofluorescence, and immunogold electron microscopic studies did not detect such specific alterations in any control mice. CONCLUSIONS: Acquired autoimmunity to type VII collagen in patients with epidermolysis bullosa acquisita may result in a clinical phenotype closely resembling that observed in patients with dystrophic epidermolysis bullosa. Passive transfer of purified IgG autoantibodies from a patient with severe epidermolysis bullosa acquisita to BALB/c mice produces histologic and immunopathologic alterations consistent with those seen in patients with this disease.

Immunodominant autoepitopes of type VII collagen are short, paired peptide sequences within the fibronectin type III homology region of the noncollagenous (NC1) domain.

Autoantibodies to type VII collagen are associated with the blistering diseases epidermolysis bullosa acquisita and bullous systemic lupus erythematosus. We showed previously that these autoantibodies recognize epitopes within the noncollagenous (NC1) region of type VII collagen. That region is composed of fibronectin type III homology units that may contribute to intermolecular cross-linking and basement membrane adhesion functions of type VII collagen. In this study, we defined the specific amino acid sequences recognized by these autoantibodies. By fusion protein analysis, sera from patients with epidermolysis bullosa acquisita and bullous lupus were found to react with two regions within the fourth (E-1) and eighth (E-2) fibronectin homology repeats, each consisting of approximately 100 amino acids. Affinity purification studies showed E-1 and E-2 to be independent and non-cross-reactive epitope regions. These regions were probed further by enzyme-linked immunosorbent assay analysis of overlapping octapeptide sets derived from the amino acid sequences of E-1 and E-2. The results showed two reactive, closely associated octapeptide sequences within each region, both lying in amphipathic portions of fibronectin type III homology repeats. These studies identify short peptide sequences within the NC1 domain of type VII collagen that are targeted independently by autoantibodies. These sequences may play a direct role in determining the properties of type VII collagen that influence adhesion between this molecule and other basement membrane proteins, and their alteration by antibody binding may be the immunopathogenic event underlying epidermolysis bullosa acquisita and bullous lupus.

Antiepiligrin cicatricial pemphigoid. A subepithelial bullous disorder.

BACKGROUND: Epiligrin is a glycoprotein complex deposited in extracellular matrix by cultured human keratinocytes that serves as the major integrin ligand of these cells. In human skin, epiligrin is found at the interface of the lamina lucida and lamina densa in epidermal basement membrane where it is believed to be associated with anchoring filaments and plays an important role in keratinocyte adhesion. METHODS AND RESULTS: We have identified six patients with a subepithelial bullous disorder of mucous membranes and skin who have IgG anti-basement membrane autoantibodies that immunoprecipitate epiligrin from human keratinocyte extracts and culture media. These patients' IgG autoantibodies also bind epiligrin in human keratinocyte extracellular matrix and epidermal basement membrane as determined by immunofluorescence and immunoelectron microscopy. Studies of 10 patients who are clinically indistinguishable from subjects with anti-epiligrin autoantibodies (ie, cicatricial pemphigoid patients) found that while seven had anti-basement membrane autoantibodies, the latter are directed exclusively against a region of epidermal basement membrane that does not contain epiligrin, are present in low titer (ie, < or = 1:10), do not react with keratinocyte extracellular matrix, and do not bind epiligrin (or any other specific antigen) in immunoprecipitation studies of human keratinocyte extracts or media. Antiepiligrin autoantibodies were also not detected in studies of 36 additional patients with bullous diseases or six normal volunteers. CONCLUSIONS: Cicatricial pemphigoid is a disease phenotype in which patients' autoantibodies may target different constituents of epidermal basement membrane. Antiepiligrin autoantibodies are a specific immunologic marker for a group of patients with a disease entity that we propose to designate antiepiligrin cicatricial pemphigoid.

Epidermolysis bullosa acquisita and bullous systemic lupus erythematosus. Diseases of autoimmunity to type VII collagen.

Autoimmunity to C7 is a genetically predisposed condition that results in the production of predominantly IgG class basement membrane autoantibodies that may cause basement membrane damage and subepidermal blisters by at least two pathogenic mechanisms. Autoimmunity to C7 cuts across traditional disease classifications (EBA versus bullous SLE), presents with heterogeneous clinical and pathologic features, mimics other diseases, and may be difficult to diagnose and treat. Autoimmunity to C7 is associated with susceptibility to SLE and perhaps inflammatory bowel disease.

Autoantibodies to type VII collagen recognize epitopes in a fibronectin-like region of the noncollagenous (NC1) domain.

Autoantibodies to type VII collagen are characteristic of the blistering diseases epidermolysis bullosa acquisita and bullous systemic lupus erythematosus (SLE). Blisters in those diseases are due to defective adhesion of the lamina densa subregion of the epithelial basement membrane to the underlying dermis. Previous studies indicating that type VII collagen contributes to lamina densa-dermal adhesion by cross-linking lamina densa and dermal matrix proteins suggests that autoantibodies may contribute to blisters by interfering with type VII collagen function. That hypothesis is supported by previous studies showing autoantibodies from a small number of epidermolysis bullosa acquisita patients recognize proteolytic fragments containing the 145-kD noncollagenous domain of type VII collagen. In this study, we examined reactivity of autoantibodies from a large number of epidermolysis bullosa acquisita and bullous SLE patients with fusion proteins representing most of the noncollagenous domain of type VII collagen and that those regions are homologous to type III repeats of fibronectin. These results suggest autoantibodies binding to fibronectin homology regions within the 145-kD noncollagenous domain may interfere with the adhesion function of type VII collagen and contribute to lamina densa-dermal dysadhesion in epidermolysis bullous acquisita and bullous SLE.

Inhibition of neutrophil adherence to antibody by dapsone: a possible therapeutic mechanism of dapsone in the treatment of IgA dermatoses.

Dapsone is frequently effective in cutaneous diseases characterized by antibody deposition and accumulation of neutrophils. We hypothesized that this mechanism of action of dapsone may involve the inhibition of neutrophil adherence to antibody. The neutrophil adherence assay, which measures the binding of neutrophils to basement membrane zone-bound antibody on skin sections, was used to evaluate the effect of dapsone on neutrophil adherence to immunoglobulin A and immunoglobulin G. We evaluated the effect of dapsone on adherence of normal neutrophils to immunoglobulin A and immunoglobulin G from sera of linear immunoglobulin A bullous dermatosis and bullous pemphigoid patients, respectively. Linear immunoglobulin A bullous dermatosis or bullous pemphigoid antibody were bound to the basement membrane zone of normal skin sections as a substrate for the neutrophil adherence assay. Dapsone was added directly to the neutrophils or to the antibody source in concentrations of 0-50 micrograms/ml (pharmacologic range). Addition of dapsone to neutrophils produced an incremental inhibition of neutrophil adherence up to 75% at 50 micrograms/ml. Dapsone produced similar inhibition when added directly to the antibody itself, despite washing prior to usage in the neutrophil-adherence assay. Control specimens including irrelevant fractions of patient sera failed to demonstrate binding. Serum from a patient on dapsone therapy also showed inhibition of neutrophil adherence compared to the same patient on no therapy. We conclude that dapsone inhibits the adherence of neutrophils to basement membrane zone antibody in a dose-dependent manner. This may be related to an effect directly on antibody. This inhibition may contribute to the clinical efficacy of dapsone in antibody-mediated diseases.

Bullous SLE: a phenotypically distinctive but immunologically heterogeneous bullous disorder.

Bullous systemic lupus erythematosus (SLE) is a rare blistering disease with a distinctive combination of clinical, histologic and immunopathologic features that together constitute a unique bullous disease phenotype. There appear to be at least two immunologically distinct subtypes of bullous SLE characterized by the presence or absence of circulating and/or tissue-bound basement membrane zone autoantibodies that recognize type VII collagen. The two subtypes are not clearly distinguishable except by indirect immunofluorescence and/or direct immunoelectron microscopy. In patients without circulating antibodies, immunoelectron microscopy is required to distinguish between the two subtypes. Patients with autoantibodies to type VII collagen are similar but not identical to patients with epidermolysis bullosa acquisita--another bullous disease associated with autoantibodies to type VII collagen. Autoantibodies to type VII collagen in patients with bullous SLE is only one of several lines of evidence that indicate autoimmunity to that protein and susceptibility to SLE are associated phenomena. In addition, there is emerging evidence for an association between epidermolysis bullous acquisita and SLE. There is also evidence that autoantibodies to type VII collagen are pathogenic in bullous SLE (and epidermolysis bullosa acquisita) and that their production is regulated by the class II major histocompatibility complex DR beta 1 allele, 1501 and possibly other DR beta 1 alleles that share a similar sequence of amino acids in the second hyper-variable region.

Normal molecular weight of type VII collagen produced by recessive dystrophic epidermolysis bullosa keratinocytes.

Studies of the recessive dystrophic form of epidermolysis bullosa (RDEB) have suggested that an abnormality in type VII collagen may be involved in the pathogenesis of this disorder. Indirect immunofluorescence studies have shown that the staining for type VII collagen along the dermal-epidermal junction is markedly reduced or absent in all but rare cases of severe, generalized RDEB. These findings imply that the genetic defect may involve type VII collagen but do not exclude the possibility that the alterations demonstrated are secondary, for example, to nonspecific proteolysis of type VII collagen. To evaluate the ability of cells of affected patients to produce type VII collagen, we cultured keratinocytes from a severely affected patient and immunoprecipitated type VII collagen from the cells. Keratinocytes were metabolically labelled with 35S-methionine, and solubilized cell extracts were reacted with antibody to type VII collagen. The results indicate that the patient's keratinocytes synthesize type VII collagen and that the M(r) of the protein synthesized does not differ from that of an unaffected control. Because cultured cells from a patient severely affected with recessive dystrophic epidermolysis bullosa produce type VII collagen, the genetic defect, at least in this patient, is unlikely to reside in a major truncation of the type VII collagen molecule.

Noncollagenous (NC1) domain of collagen VII resembles multidomain adhesion proteins involved in tissue-specific organization of extracellular matrix.

Type VII collagen (C7) is a stratified squamous epithelial basement membrane protein composed of three identical alpha chains, each consisting of a 145-kDa amino-terminal noncollagenous (NC1) domain and a 145-kDa carboxyl-terminal collagenous domain. Morphologic and biochemical studies have shown that tissue-specific aggregates of C7 dimers called anchoring fibrils may contribute to epithelial basement membrane organization and adherence by interacting with extracellular matrix (ECM) proteins such as type IV collagen. In this study, we cloned a cDNA encoding most of the NC1 domain of C7. The deduced amino acid sequence revealed motifs characteristic of multidomain ECM proteins that contribute to the tissue-specific organization of ECM including a region of 7 1/2 sequential fibronectin type III (Fn III) homology repeats, a potential collagen-binding region homologous to the A domain of von Willebrand factor (vWf) and an RGD sequence. A purified C7 fusion protein containing these motifs specifically bound to type IV collagen in a functional assay. These results suggest that regions within the NC1 domain of C7 mediate interactions with lamina densa and dermal ECM proteins including type IV collagen. Structural mutations and autoepitopes in these regions may represent mechanisms for the development of defective basement membrane organization and adherence in genetic and autoimmune forms of epidermolysis bullosa.

Epiligrin, the major human keratinocyte integrin ligand, is a target in both an acquired autoimmune and an inherited subepidermal blistering skin disease.

Epiligrin, the major component of human keratinocyte extracellular matrix, serves as the preferred integrin ligand for alpha 3 beta 1 in plasma membranes and focal adhesions, and colocalizes with alpha 6 beta 4 in hemidesmosomes. In human skin, epiligrin is found in the lamina lucida subregion of epidermal basement membrane, where it is thought to be associated with anchoring filaments. We have identified three patients with an acquired mucosal predominant subepidermal blistering disease who have IgG anti-basement membrane autoantibodies that bind the lamina lucida/lamina densa interface of epidermal basement membrane, stain cultured human keratinocyte extracellular matrix, and immunoprecipitate disulfide linked polypeptides of 170, 145, 125, and 95 kD in human keratinocyte culture media in a pattern identical to that of P1E1, a murine monoclonal antiepiligrin antibody. Comparative immunoprecipitation studies of patient sera, P1E1, and GB3 monoclonal antibody show that epiligrin is identical to the antigen (i.e., BM600 or GB3 antigen) previously reported to be absent from the skin of patients with lethal junctional epidermolysis bullosa, an inherited subepidermal blistering disease. Moreover, skin from a fetus with this disease shows no evidence of reactivity to patient antiepiligrin autoantibodies or P1E1. These studies show that antiepiligrin autoantibodies are a specific marker for a novel autoimmune blistering disease and that the epidermal basement membrane antigen absent in patients with lethal junctional epidermolysis bullosa is epiligrin.

Pustular eruption of the striae in a primigravida.

We report on a patient with a pustular eruption of the striae in an otherwise normal first pregnancy. The clinical, histologic, and immunologic findings are reviewed and found to be inconsistent with pruritic urticarial papules and plaques of pregnancy and with the three previously described pustular eruptions of pregnancy (impetigo herpetiformis, pruritic folliculitis of pregnancy, and autoimmune progesterone dermatitis of pregnancy). Therefore, we regard this case as unique.

A bullous skin disease patient with autoantibodies against separate epitopes in 1 mol/L sodium chloride split skin.

BACKGROUND: We describe a patient with a subepidermal bullous skin disease associated with autoantibodies recognizing separate epitopes in 1 mol/L sodium chloride (NaCl) split skin. OBSERVATIONS: Direct immunofluorescence microscopy showed deposits of immunoglobulins and C3 in a continuous pattern in the patient's epidermal basement membrane zone. Direct immunoelectron microscopy demonstrated thick deposits of IgG overlying the lamina lucida and the lamina densa in a unique pattern. The patient had circulating IgG anti-basement membrane zone antibodies that bound both sides of 1 mol/L NaCl split skin, exhibited at least a fourfold-higher titer against the dermal side of this test substrate, and bound basal keratinocyte hemidesmosomes as well as focal sites along the superior portion of the lamina densa on indirect immunoelectron microscopy. Affinity purification of anti-basement membrane zone antibodies against epidermal or dermal strips of 1 mol/L NaCl split skin yielded IgG that only bound the side of split skin from which it was eluted. The patient's serum contained IgG that immunoprecipitated and immunoblotted the 230- and 170-kd bullous pemphigoid antigens. Affinity purification of patient antibody against bullous pemphigoid antigen immobilized on nitrocellulose paper yielded IgG that bound only the epidermal side of 1 mol/L NaCl split skin. The patient showed no evidence of reactivity against type VII collagen by direct immunoelectron microscopy, indirect immunoelectron microscopy, or immunoblot. CONCLUSIONS: This patient's bullous skin disease is associated with IgG anti-basement membrane zone antibodies with two specificities: one recognizing the bullous pemphigoid antigen in the epidermal side of 1 mol/L NaCl split skin, and another binding a distinct, yet presently unidentified, epitope in the superior aspect of the lamina densa.

Immunofluorescence on split skin for the detection and differentiation of basement membrane zone autoantibodies.

The autoimmune subepidermal bullous diseases are characterized by autoantibodies to the basement membrane zone of stratified squamous epithelium. Recent studies have shown that the antibodies have characteristic ultrastructural and antigenic binding properties and that differentiating between those properties can be useful in distinguishing one disease from another. Immunofluorescence microscopy is widely used to detect basement membrane zone autoantibodies. The test has traditionally used tissue substrates with an intact basement membrane zone. Those substrates are limited because autoantibody binding cannot always be detected and because autoantibodies with different ultrastructural and antigenic binding properties cannot be distinguished from each other. Normal human skin that has been separated through the basement membrane zone (i.e., split skin) has recently been used as a substrate for detecting and characterizing basement membrane zone autoantibodies by immunofluorescence. Studies indicate that split skin is a more sensitive substrate than intact skin for detecting the antibodies and that antibodies with different ultrastructural binding sites can often be differentiated from one another on split skin. Those studies suggest split skin is the substrate of choice for the routine immunofluorescence evaluation of autoimmune subepidermal bullous diseases.

Studies on complement deposits in epidermolysis bullosa acquisita and bullous pemphigoid.

Epidermolysis bullosa acquisita (EBA) is an inflammatory subepidermal blistering disease characterized by circulating and tissue-bound autoantibodies specific for type VII collagen of the basement membrane zone. The antibodies consist of both complement- and noncomplement-binding populations and belong to all four subclasses of IgG. We investigated the presence of the membrane attack complex C3b, C5, and S protein in EBA and compared C3b and C5 in EBA and bullous pemphigoid. In 10 patients with EBA, these components were detected at the basement membrane zone as follows: membrane attack complex, 90%; S protein, 90%; direct C5, 90%; C3b, 100%; and C5 binding, 90%. In the patients with bullous pemphigoid, the results were as follows: direct C5, 58%; C3b, 33%; and C5 binding, 19%. These results provide additional evidence for complement activation at the basement membrane zone in EBA, show that complement activation in EBA proceeds to activation of terminal complement components, and suggest that EBA antibodies are more potent activators of C5 than are bullous pemphigoid antibodies.

Characterization of the changes in matrix molecules at the dermoepidermal junction in lupus erythematosus.

Electron microscopy has revealed that the deposition of immunoglobulin in the skin of lupus erythematosus (LE) patients occurs on and below the basal lamina of the basement membrane (BM). The composition of the BM is now to some extent known, and antibodies have been developed against several of its individual components. In this study, we attempt to elucidate the status of some matrix molecules in the dermoepidermal junction in LE. Lesional and nonlesional skin from LE patients was examined using immunofluorescence microscopy with monoclonal and polyclonal antibodies against 6 matrix molecules. Immuno-electron microscopy using monoclonal antibodies was used to discern changes in type IV and type VII collagen. By immuno-fluorescence microscopy, type IV collagen, type VII collagen, and fibronectin were altered in lesional skin. There was a statistically significant correlation between the presence of immunoglobulin and alteration of type IV collagen and type VII collagen in lesional skin. The alterations in type IV and type VII collagens were confirmed on immuno-electron microscopy which showed fragmentation of staining of both antigenic components, particularly type IV collagen.

Direct immunofluorescence microscopy of 1 mol/L sodium chloride-treated patient skin.

Patients with bullous pemphigoid and those with epidermolysis bullosa acquisita often demonstrate virtually identical clinical, histologic, and immunopathologic features. Although some patients can be distinguished by their pattern of circulating IgG anti-basement membrane zone antibody binding to 1 mol/L sodium chloride-split human skin, approximately 20% and 50% of bullous pemphigoid and epidermolysis bullosa acquisita patients, respectively, do not possess such antibodies. Hence this study sought to determine whether these patients can be distinguished by mapping the distribution of basement membrane zone immunoreactants in patient skin split in vitro by 1 mol/L sodium chloride. All sodium chloride-treated samples from patients with bullous pemphigoid (n = 8), epidermolysis bullosa acquisita (n = 4), or other bullous skin diseases (n = 6) contained a lamina lucida cleavage plane bounded by bullous pemphigoid antigen and laminin; moreover, treatment of patient samples was performed without loss of tissue substrate or in situ immunoreactants. Deposits of IgG were found on the epidermal side of sodium chloride-treated skin from 13 of 14 bullous pemphigoid samples; IgG deposits in bullous pemphigoid samples were exclusively epidermal in eight, epidermal and dermal in five, and solely dermal in one. In contrast, IgG was found exclusively on the dermal side of sodium chloride-treated samples from patients with epidermolysis bullosa acquisita. Although IgG mapping distinguished bullous pemphigoid and epidermolysis bullosa acquisita patients in 94% of these samples, the distribution of C3 in sodium chloride-treated patient skin was more variable and less predictive diagnostically.(ABSTRACT TRUNCATED AT 250 WORDS)

Childhood epidermolysis bullosa acquisita. Report of three cases and review of literature.

Epidermolysis bullosa acquisita is an acquired subepidermal blistering disease with variable clinical, pathologic, and immunologic features. The disease has been reported infrequently in adults and only rarely in children. We describe three new cases of childhood epidermolysis bullosa acquisita, review three previously reported cases, and contrast the features of the disease in children with those in adults. The results suggest that both children and adults with epidermolysis bullosa acquisita have variable clinical and pathologic features that may mimic other bullous diseases. Epidermolysis bullosa acquisita is characterized by a chronic course, poor response to therapy, and occasional clinical remissions.

Epidermolysis bullosa acquisita: a disease of autoimmunity to type VII collagen.

Epidermolysis bullosa acquisita (EBA) is one of a group of primary blistering diseases characterized by dermal/epidermal separation at the basement membrane (BM) of stratified squamous epithelium and IgG anti-BM autoantibodies (ABM). EBA ABMs can be distinguished from IgG ABMs in all other primary blistering diseases by their reactivity with the BM matrix protein, type VII collagen (C-VII). The clinical and histological features of EBA are highly variable and may be indistinguishable from those of other primary bullous diseases. The diagnosis can be confirmed by one of several methods that directly or indirectly demonstrate IgG ABMs to C-VII. IgG ABMs to C-VII are not specific for EBA. They have been described in SLE patients with and without a secondary blistering eruption, bullous eruption of SLE (BSLE). IgA ABMs to C-VII have been described in a subgroup of patients with linear IgA bullous dermatosis. Recent evidence suggests that autoimmunity to C-VII in EBA and BSLE is regulated by the same genes within the major histocompatibility complex (MHC) and contributes to the pathogenesis of acute inflammation and blisters in both disorders. The finding of ABMs to C-VII in SLE and BSLE, evidence that EBA and BSLE share an immunogenetic predisposition to C-VII autoimmunity, and an apparent association between susceptibility to SLE and EBA suggest a close relationship between SLE and autoimmunity to C-VII.

Acquired epidermolysis bullosa. A bullous disease associated with autoimmunity to type VII (anchoring fibril) collagen.

Epidermolysis bullosa acquisita (EBA) is a chronic subepidermal blistering disease of the skin in which one finds tissue-bound and circulating antibodies are bound to type VII collagen. Although not definitely proven, current evidence strongly suggests that EBA is an autoimmune disease. The true etiology or initiating event that triggers EBA has not been identified.