Serration pattern analysis for differentiating epidermolysis bullosa acquisita from other pemphigoid diseases

1. Download high-res image (152KB)
2. Download full-size image

     

Recommendations for the use of immunoapheresis in the treatment of autoimmune bullous diseases

Despite the use of high‐dose systemic corticosteroids in combination with other immunosuppressants, in some patients with autoimmune bullous diseases only insufficient improvement is achieved. In these cases and in acute severe disease, adjuvant immunoapheresis has been increasingly used. A consensus meeting was held in mid‐2005 in Hamburg, aiming at developing guidelines for the use of immunoapheresis in the treatment of autoimmune bullous diseases.This paper summarizes the experts‘ recommendations.     

Animal models for autoimmune bullous dermatoses

Abstract:  Autoimmune bullous dermatoses are a group of severe diseases, which are clinically characterized by blisters and erosions of skin and/or mucous membranes. In order to investigate the pathogenesis of these potentially life-threatening diseases and to develop more specific therapeutic approaches, animal models have been developed that aim to reproduce the clinical, histological and immunopathological findings. We here review established and novel animal models of autoimmune skin blistering diseases and discuss their applications and limitations.     

Evidence for pathogenicity of autoreactive T cells in autoimmune bullous diseases shown by animal disease models

Autoimmune bullous diseases (AIBDs) are characterized by blisters and erosions on the skin and/or mucous membranes, which are caused by autoantibodies directed to structural proteins of the epidermis and the epidermal basement membrane zone. This Viewpoint Essay discusses the contribution by autoreactive T cells to the pathogenesis of bullous pemphigoid, pemphigus and epidermolysis bullosa acquisita, with an emphasis on studies using active animal mouse models for these diseases. Previous studies have demonstrated that cytokines produced by autoreactive T cells, the interaction between antigen‐specific T cells and B cells and the function of regulatory T cells are likely related to the pathogenesis of AIBDs. In interpreting the experimental results, the limitations of those animal models should be considered. Further understanding of the pathogenicity of autoreactive CD4⁺ T cells may lead to disease‐specific treatments.     

Binding of avian IgY to type VII collagen does not activate complement and leucocytes and fails to induce subepidermal blistering in mice

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a severe autoimmune skin disease characterized by tissue-bound and circulating autoantibodies to type VII collagen, the major component of anchoring fibrils. When passively transferred into mice, rabbit IgG against type VII collagen induces Fc-dependent activation of complement, the recruitment of leucocytes into the skin, and subepidermal blistering. In addition to these inflammatory mechanisms, clinical and experimental evidence suggests that antibodies against type VII collagen might induce blisters by disrupting the ligand function of type VII collagen by an Fc-independent mechanism. OBJECTIVES: To study noninflammatory mechanisms of blister formation in experimental EBA. METHODS: We generated chicken IgY antibodies directed to recombinant type VII collagen and examined their pathogenic activity using ex vivo and animal models. RESULTS: Mice injected with these chicken IgY antibodies showed binding of the antibodies to the dermal-epidermal junction of skin sections. However, IgY antibodies did not fix complement C3 in enzyme-linked immunosorbent assay and immunofluorescence complement-binding assays. In addition, IgY antibodies did not induce dermal-epidermal separation ex vivo. Following their passive transfer into Balb/c mice, chicken IgY antibodies against type VII collagen bound at the dermal-epidermal junction, but, in contrast to rabbit IgG, did not fix complement C3, recruit granulocytes, or induce skin blisters. CONCLUSIONS: These findings demonstrate that binding of avian IgY to type VII collagen is not pathogenic in vivo and strongly suggest that in experimental EBA, antibodies to type VII collagen induce blisters not by direct disruption of the ligand function of type VII collagen, but rather by an Fc-dependent engagement of humoral and cellular inflammatory factors.     

Childhood epidermolysis bullosa acquisita with autoantibodies against the noncollagenous 1 and 2 domains of type VII collagen: case report and review of the literature

Epidermolysis bullosa acquisita (EBA) is an acquired subepidermal bullous disease characterized by IgG autoantibodies to type VII collagen, a major component of anchoring fibrils. Most patients with EBA are adult and develop autoantibodies to the noncollagenous (NC) 1 domain of type VII collagen. We describe a 4-year-old Japanese boy presenting pruritic vesicles and tense blisters over his whole body. Immunofluorescence studies revealed linear IgG/C3 deposits along the dermal-epidermal junction of the patient's skin, and circulating IgG autoantibodies mapping to the dermal side of 1 M NaCl-split skin. By immunoblotting analysis using dermal extracts as a substrate, the patient's IgG antibodies labelled a 290-kDa protein corresponding to type VII collagen. Immunoblotting studies using recombinant proteins demonstrated that the patient's circulating autoantibodies recognized not only the NC1 but also the NC2 domain of type VII procollagen. Review of the previously reported cases and the present case suggested that patients with EBA with autoantibodies to regions other than the NC1 domain are all children younger than 10 years of age with clinical features of an inflammatory phenotype.     

Unique mouse monoclonal antibodies reactive with maturation‐related epitopes on type VII collagen

In this study, we generated a new set of monoclonal antibodies (mAbs) to bovine and human type VII collagen (COL7) by immunizing mice with bovine cornea‐derived basement membrane zone (BMZ) fraction. The four mAbs, tentatively named as COL7‐like mAbs, showed speckled subepidermal staining in addition to linear BMZ staining of normal human skin and bovine cornea, a characteristic immunofluorescence feature of COL7, but showed no reactivity with COL7 by in vitro biochemical analyses. Taking advantage of the phenomenon that COL7‐like mAbs did not react with mouse BMZ, we compared immunofluorescence reactivity between wild‐type and COL7‐rescued humanized mice and found that COL7‐like mAbs reacted with BMZ of COL7‐rescued humanized mice. In ELISAs, COL7‐like mAbs reacted with intact triple‐helical mammalian recombinant protein (RP) of COL7 but not with bacterial RP. Furthermore, COL7‐like mAbs did not react with COL7 within either cultured DJM‐1 cells or basal cells of skin of a bullous dermolysis of the newborn patient. These results confirmed that COL7‐like mAbs reacted with human and bovine COL7. The epitopes for COL7‐like mAbs were considered to be present only on mature COL7 after secretion from keratinocytes and deposition to BMZ and to be easily destroyed during immunoblotting procedure. Additional studies indicated association of the speckled subepidermal staining with both type IV collagen and elastin. These unique anti‐COL7 mAbs should be useful in studies of both normal and diseased conditions, particularly dystrophic epidermolysis bullosa, which produces only immature COL7.     

High-dose intravenous immune globulin for the treatment of autoimmune blistering diseases: an evaluation of its use in 14 cases

High-dose intravenous immune globulin (IVIG) is used to treat a wide variety of autoimmune diseases. We report our experiences of its use in a retrospective study of 14 patients with autoimmune blistering diseases, namely epidermolysis bullosa acquisita (EBA), two; bullous pemphigoid (BP), two; pemphigoid gestationis (PG), one; nodular pemphigoid, two; and pemphigus vulgaris (PV), seven. Two patients with refractory EBA improved following regular courses of IVIG given as monotherapy. IVIG had a steroid-sparing effect in 10 patients with PV, BP and PG. However, the clinical effects were transient and of variable intervals, and repeated courses of IVIG were required. The rapid actions of IVIG were of particular benefit in two patients with extensive, rapidly progressive PV and in one patient with BP in whom swift disease control was required. In such cases, when rapid disease control is paramount, we recommend IVIG used in conjunction with conventional treatments as a safer and less invasive alternative to plasmapheresis. IVIG was ineffective in two patients with nodular pemphigoid. Analysis of indirect immunofluorescence (IIF) titres before and after IVIG showed that a fall in titre occurred after 78% of treatments and was observed in all disease groups. However, like the clinical improvements, the falls in IIF titres were transient and of variable interval, and titres rose back to pretreatment levels in all but one patient. IVIG appears to be beneficial under certain circumstances for the treatment of autoimmune blistering diseases but controlled trials are required to define its therapeutic role further.     

Clearance rates of circulating and tissue‐bound autoantibodies to type VII collagen in experimental epidermolysis bullosa acquisita

Background Epidermolysis bullosa acquisita (EBA) is a severe autoimmune skin disease characterized by autoantibodies to type VII collagen, the major component of anchoring fibrils. In this and other autoimmune bullous dermatoses, specific autoantibody detection systems are not only of diagnostic use but also allow monitoring of circulating and skin‐bound autoantibodies during the course of the disease. However, little is known about their natural clearance rates in these different compartments. Objectives To study clearance rates of circulating and tissue‐bound autoantibodies to type VII collagen in experimental EBA. Methods Using offspring from mice with experimentally induced EBA, we examined retention times of diaplacentally transmitted autoantibodies to type VII collagen in serum of neonatal mice by enzyme‐linked immunosorbent assay and of immunoreactant deposits in skin by direct immunofluorescence microscopy. Additionally, the pathogenic potential of transmitted autoantibodies was evaluated in descendant mice. Results Immediately after birth, comparable levels of pathogenic antibody concentrations were observed in maternal and neonatal mice. The clearance time of skin‐bound autoantibodies was twice as long as that of circulating autoantibodies (8 and 4 weeks, respectively). Maternofetal transfer of pathogenic autoantibodies produced specific immunopathological (IgG, IgG1, IgG2a/b and complement C3 deposits) but not histological or clinical alterations in skin of offspring mice. Conclusions Although still to be confirmed in humans, our findings add to the knowledge on turnover rates of circulating and skin‐bound autoantibodies in autoimmune bullous dermatoses, which in turn may facilitate a more specific monitoring of these antibodies during the disease course, reduce the need for repeated skin biopsies, and may also be helpful in guiding treatment decisions.     

Ultrastructural immunocytochemistry of autoimmune bullous diseases

Advanced immunopathological assays have been developed to elucidate the pathophysiology and provide more precise nosological definitions of the immunobullous diseases. Forty-seven patients suffering from autoimmune bullous diseases (intra- or subepidermal) were studied by immunoelectron microscopy (direct and indirect). Peroxidase staining was revealed by diaminobenzidine (determination of immune deposit location) in the majority of the cases of subepidermal bullous diseases, but in less than half of the cases of intraepidermal bullous diseases. Immunoelectron microscopy features contributed in verifying the diagnosis of rare entities such as cicatricial pemphigoid, paraneoplastic autoimmune bullous disease, linear IgA disease and epidermolysis bullosa acquisita.     

Autoimmune bullous skin diseases. Part 1: Clinical manifestations

Autoimmune bullous skin diseases are characterized by autoantibodies against adhesion molecules of the skin. Pemphigus is a disorder with an intraepidermal loss of adhesion and is characterized by fragile blisters and erosions. Pemphigus vulgaris often shows extensive lesions of the oral mucosa, while pemphigus foliaceus is commonly restricted to cutaneous involvement with puff pastry-like scale formation. Paraneoplastic pemphigus is obligatorily associated with malignancies and often presents as hemorrhagic stomatitis with multiforme-like exanthems. IgA pemphigus typically presents with pustules and annular plaques but not with mucosal involvement. The clinical spectrum of the pemphigoids includes tense blisters, urticarial plaques, and prurigo- like eczematous lesions. Pemphigoid gestationis mostly occurs during the last trimester of pregnancy and mucous membrane pemphigoid primarily involves the oral mucosa and conjunctivae and leads to scarring. Linear IgA bullous dermatosis manifests with tense blisters in a "cluster of jewels"-like pattern in childhood and is more heterogeneous in adulthood. Classical epidermolysis bullosa acquisita shows extensive skin fragility. Dermatitis herpetiformis is associated with gluten-sensitive enteropathy and manifests clinically with severe itching and papulovesicles on the extensor surfaces of the extremities and the lumbosacral area. The intention of the review is to demonstrate the heterogeneous clinical spectrum of autoimmune bullous disorders.     

A case of acquired autoimmune bullous disease associated with IgM macroglobulinaemia.

A variety of autoimmune bullous dermatoses have been reported to develop in association with lymphoproliferative disorders. We report a patient with IgM macroglobulinaemia, who presented with a skin fragility similar to but somewhat milder than that seen in epidermolysis bullosa acquisita. Immunofluorescence detected circulating IgM autoantibodies reacting with the basement membrane zone, which reacted predominantly with dermal side of 1 M NaCl-split skin. Immunoblotting of the epidermal and dermal extracts with the patient's serum showed no specific reactivity. Further studies are needed to identify the antigenic molecules responsible for the IgM deposition.     

Epidermolysis bullosa acquisita sera react with distinct epitopes on the NC1 and NC2 domains of type VII collagen: study using immunoblotting of domain-specific recombinant proteins and postembedding immunoelectron microscopy

BACKGROUND: The sera of epidermolysis bullosa acquisita (EBA) react with type VII collagen, a major component of anchoring fibrils, in which the major epitopes have been considered to be present in the N-terminal noncollagenous (NC) 1 domain. OBJECTIVES: To determine whether there are also epitopes in the C-terminal NC2 domain, and to determine their ultrastructural localization. METHODS: Immunoblotting using recombinant proteins of the NC1 and NC2 domains of type VII collagen, and postembedding immunoelectron microscopy. RESULTS: Twenty of 28 EBA sera tested reacted with the NC1 domain and eight sera reacted with the NC2 domain. The sera that reacted with the NC1 domain showed immunoreactivity within the lamina densa and the sera that reacted with the NC2 domain showed immunoreactivity in the dermis 300-360 nm below the lamina densa. CONCLUSIONS: This study clearly identified the presence of epitopes in the NC2 domain, and showed that the epitope in the NC1 domain is present in the lamina densa and that the epitope in the NC2 domain is in the dermis below the lamina densa.     

Molecular biology and pathology of type VII collagen.

Type VII collagen is a genetically distinct member of the collagen family of proteins. Type VII collagen has been shown to be the major component of anchoring fibrils, attachment complexes which secure the cutaneous basement membrane of the skin to the underlying dermis. Understanding of the structure of type VII collagen has been advanced by recent cloning of the corresponding gene. Chromosomal mapping of the gene to the short arm of chromosome 3 and identification of intragenic polymorphic markers have allowed demonstration of strong genetic linkage between the type VII collagen locus and the dystrophic forms of EB (epidermolysis bullosa). This overview summarizes the progress made in the molecular genetics of type VII collagen.     

Case with Brunsting–Perry‐like localized subepidermal blister formations and immunoglobulin G antibodies against unidentified basement membrane zone antigen

Brunsting–Perry type bullous pemphigoid is defined by the blister formation limited to the head and neck, and autoantibodies to type VII collagen are detected in several cases. However, the pathomechanisms and autoantigens in this condition remain unknown. We report a 20‐year‐old female patient with a more than 2‐year history of recurrent tense blisters localized on the face with no distinct atrophic scar formation. The patient had neither extensive sun exposure nor a history suggestive of contact dermatitis. Oral betamethasone was effective on the skin lesions. Histopathology revealed subepidermal blister formation with dermal infiltrates of neutrophils. Although direct and indirect immunofluorescence tests detected immunoglobulin G antibodies to the basement membrane zone (BMZ), no known dermal or epidermal autoantigens were detected in immunoblot analyses. Therefore, this case may be a rare variant of Brunsting–Perry type localized bullous pemphigoid with autoantibodies to an undetermined BMZ antigen.     

Spectrum of subepidermal immunobullous disorders seen at the National Skin Centre,Singapore: a 2-year review

BACKGROUND: The subepidermal immunobullous disorders (SEIBDs) comprise bullous pemphigoid (BP), cicatricial pemphigoid (CP), epidermolysis bullosa acquisita (EBA), linear IgA disease (LAD), dermatitis herpetiformis (DH), pemphigoid gestationis (PG) and bullous systemic lupus erythematosus (BSLE). They are thought to be rarer in the Far East than in western Europe. OBJECTIVE: This 2-year retrospective study investigates the spectrum seen at our centre and the minimum estimated incidence of each. PATIENTS AND METHODS: A total of 67 patients seen at the National Skin Centre (NSC), Singapore between January 1998 and December 1999 were diagnosed as having an SEIBD. Fifty-nine (88%) had BP, four (6%) had EBA, two (3%) LAD and two (3%) BSLE. There were no cases of CP, DH or PG diagnosed during this period. The minimum estimated incidence in our local population was 7.6, 0.5, 0.26 and 0.26 per million population per year, respectively. The mean age of onset was 77, 68, 65 and 31 years, respectively. RESULTS: BP is the commonest SEIBD seen locally, with an incidence at least equal to that in western Europe. It is diagnosed at our centre three times more frequently than pemphigus. There is a predilection for ethnic Chinese but not Indian. EBA is twice as common as in western Europe and shows a predilection for ethnic Indians. LAD is rare here compared to China, despite the predominant Chinese population. BSLE is also rare. In contrast to western Europe, CP, DH and PG are very rare in Singapore. CONCLUSIONS: This is the first study from this region to show that certain SEIBDs are not rarer in the Far East, as previously thought.     

Heterogeneity of Brunsting-Perry type pemphigoid: a case showing blister formation at the lamina lucida, immune deposition beneath the lamina densa and autoantibodies against the 290-kD polypeptide along the lamina densa

An otherwise healthy 31-year-old man presented with multiple, vesicular, subepidermal blistering on the head, face, chest and oral cavity, leaving shallow scar formation, typical of Brunsting-Perry type pemphigoid. Direct immunofluorescence showed linear deposition of immunoglobulin (Ig)G and C3 along the basement membrane zone (BMZ), and indirect showed anti-BMZ autoantibodies (IgG, >40×) reacting with the dermal side under the salt-split study. Immunofluorescence staining for type IV collagen and laminins, as well as routine electron microscopy, demonstrated that the cleavage level of the blister was intra-lamina lucida. The immunoperoxidase method applied to lesional skin demonstrated IgG deposits along the lamina densa. The post-embedding immunogold method demonstrated that the autoantibodies against BMZ reacted with the lamina densa and the dermis just beneath it. Immunoblot studies demonstrated that the autoantibodies reacted with the 290-kD polypeptide (suggesting type VII collagen) when dermal extract was used as the substrate. The patient was treated with combination therapy consisting of 30 mg prednisolone, 900 mg nicotinamide and 750 mg tetracycline, and the number of newly forming blisters decreased. We concluded that Brunsting-Perry type pemphigoid, a rare autoimmune blistering disease, includes cases showing characteristics of epidermolysis bullosa acquisita as well as bullous pemphigoid. This case showed discrepancy between the blistering level (intra-lamina lucida) and location of antigen (lamina densa and sub-lamina densa areas).     

Refractory bullous pemphigoid leaving numerous milia during recovery

Recovery with milia may occur in bullous pemphigoid (BP), mucous membrane pemphigoid (MMP) and epidermolysis bullosa acquisita (EBA). Scarring commonly occurs in MMP and EBA. Here, we report a 62‐year‐old man patient with BP, who was left with numerous milia during recovery. The patient had immunoglobulin (Ig)G autoantibodies to the recombinant protein of the BP180‐NC16a domain and the soluble 120‐kDa ectodomain of BP180 (linear IgA bullous dermatosis [LAD]‐1). There are cases of BP with IgG autoantibodies to LAD‐1 and/or the recombinant protein of BP180 C‐terminal domain. Extensive milia formation during recovery may be associated with immunological predisposition and/or improper interaction between hemidesmosomes and the extracellular matrix components.