Biomedical subjects

W R Gammon

Publications and source records attributed to W R Gammon.

At least 19 recordsLinked to original sources

PubMed1995

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.

Amino Acid Sequence↗

PubMed1995

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.

Adult↗

PubMed1993

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.

Autoantibodies↗

PubMed1992

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.

Autoantibodies↗

PubMed1992

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.

Amino Acid Sequence↗

PubMed1992

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.

Adult↗

PubMed1992

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.

Basement Membrane↗

PubMed1992

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.

Aged↗

PubMed1992

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.

Abdomen↗

PubMed1991

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)

Basement Membrane↗

PubMed1991

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.

Autoantibodies↗

PubMed1991

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.

Antibodies, Monoclonal↗

PubMed1991

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.

Adolescent↗

PubMed1990

Epidermolysis bullosa acquisita preceding the development of systemic lupus erythematosus.

In most cases of epidermolysis bullosa acquisita that occur in patients with systemic lupus erythematosus, the diagnosis of systemic lupus erythematosus is made before the development of blistering. We observed three patients with well-documented epidermolysis bullosa acquisita that developed several years before the onset of systemic lupus erythematosus. One patient was producing anti-U1RNP autoantibodies at the time epidermolysis bullosa acquisita was diagnosed, and all five produced this antibody during the systemic lupus erythematosus phase of their illness. In addition, in all five cases of epidermolysis bullosa acquisita with systemic lupus erythematosus antibodies to double-stranded DNA ultimately developed, and severe systemic lupus erythematosus and lupus nephritis developed in four patients. Sera from 15 other patients with epidermolysis bullosa acquisita without overt systemic lupus erythematosus were analyzed for systemic lupus erythematosus-related autoantibodies. Four patients were found to have at least one such autoantibody. These findings further document an association between epidermolysis bullosa acquisita and systemic lupus erythematosus and suggest that patients with systemic lupus erythematosus who present with epidermolysis bullosa acquisita may represent a subset of lupus erythematosus that puts the patient at increased risk for the development of more severe systemic illness. Patients presenting with epidermolysis bullosa acquisita, especially those who are black or Hispanic, should be monitored for the development of potentially life-threatening systemic lupus erythematosus.

Adult↗

PubMed1990

Direct immunofluorescence studies of sodium chloride-separated skin in the differential diagnosis of bullous pemphigoid and epidermolysis bullosa acquisita.

Bullous pemphigoid and epidermolysis bullosa acquisita may have indistinguishable clinical, histologic, and routine immunohistologic features. In those cases these two diseases can be reliably distinguished in routine diagnostic studies only in seropositive cases by tests on lamina lucida-split skin and in research studies by direct immunoelectron microscopy or, in patients with circulating autoantibodies, by immunoblotting studies. The use of these methods is limited by the expense and unavailability of the methods, the requirement for circulating autoantibodies, or both. We describe a method to distinguish between the two diseases on the basis of findings of direct immunofluorescence of a biopsy specimen after separation through the lamina lucida with 1.0 mol/L sodium chloride. The IgG appeared in the dermal side of the split specimens in epidermolysis bullosa acquisita and predominantly or exclusively in the epidermal side in pemphigoid. The method was found to be relatively simple, inexpensive, applicable to specimens preserved in transport media, and 100% reliable in our group of 22 patients.

Basement Membrane↗

PubMed1990

Placental glutathione-S-transferase-pi mRNA is abundantly expressed in human skin.

Four overlapping cDNA clones were isolated from a lambda gt11 human placenta cDNA library using purified human IgG antibody, from a patient with bullous pemphigoid. The sequence was homologous to human placenta glutathione-S-transferase-pi (GST-pi). Using the placenta clone, epidermal cDNA clones were isolated from a human keratinocyte library. Expression of GST-pi mRNA in human skin, cultured keratinocytes and fibroblasts, and disorders of squamous hyperplasia was demonstrated by Northern blotting and in situ hybridization. Human epidermal and placental cDNA clones hybridized to the same genomic DNA fragments. Hybridization of placental cDNA to interspecific somatic cell hybrids showed retention of chromosome 11, confirming the assignment of GST 3 to the long arm of chromosome 11 by molecular means. Anti-GST-pi antibody did not give a basement membrane zone pattern, although some normal and BP sera contained antibodies to GST-pi. Human skin expresses glutathione-S-transferase-pi, which belongs to an enzyme family important for detoxification and carcinogenesis.

Amino Acid Sequence↗

PubMed1990

Recombinant human cytokines stimulate neutrophil adherence to IgG autoantibody-treated epithelial basement membranes.

We investigated the ability of the purified recombinant human cytokines: tumor necrosis factor-alpha (rTNF), granulocyte-macrophage colony-stimulating factor (rGM-CSF), interleukin-1 beta (rIL-1), interleukin-3, and tumor necrosis factor-beta (rTNF-beta) to stimulate neutrophil adherence (NA) to basement membranes (BMs) of stratified squamous epithelia pretreated with autoantibodies (ABM) specific for the BM matrix protein, type-VII collagen. rTNF, rGM-CSF, rIL-1, and rTNF-beta, but not IL-3, stimulated NA and stimulation was ABM- and cytokine-concentration-dependent. Stimulation was cytokine-specific and not due to endotoxin since it was significantly inhibited by cytokine-specific antibodies but not by polymyxin B (PB). rTNF and rGM-CSF were the most potent stimulators, were effective at concentrations less than 0.067 ng/ml, and stimulated NA greater than 600%. Relative potency was: rTNF = rGM-CSF greater than rTNF-beta greater than rIL-1. Stimulation by rTNF was due to a rapid, time-dependent effect on the neutrophil, and NA appeared to be dependent, in part, on the low-affinity neutrophil receptor for IgG, Fc(gamma)RIII, because it could be specifically inhibited by monoclonal antibody (3G8) to Fc(gamma)RIII. These results suggest that rTNF, rGM-CSF, rIL-1, and rTNF-beta may contribute individually or in combination to immune-mediated inflammation and tissue injury by stimulating immune adherence of neutrophils to tissue-bound autoantibodies and immune complexes.

Antibodies, Monoclonal↗

PubMed1990

Heavy and light chain isotypes of immunoglobulin in epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic acquired blistering disease with characteristic clinical, pathologic, and immunopathologic features. The disease is characterized immunopathologically by circulating and tissue-bound IgG class autoantibodies (EBA antibodies) to the basement membrane zone of stratified squamous epithelium. Previous studies have shown that circulating and tissue-bound EBA antibodies are heterogenous in their ability to activate complement and have raised the possibility that functional heterogeneity might be related to IgG subclass restriction. In this study, we have characterized the IgG subclasses of the circulating and tissue-bound EBA antibodies by immunofluorescence and have examined the relationship between IgG subclass and complement binding. The results show that EBA antibodies belonging to all IgG subclasses are present in the skin of EBA patients. The results also show that EBA antibodies belonging to all IgG subclasses are present in the sera of most patients, including sera with and without complement binding EBA antibodies.

Basement Membrane↗