Epidermolysis Bullosa Acquisita and Bullous Systemic Lupus Erythematosus: Diseases of Autoimmunity to Type VII Collagen

Humoral Epitope Spreading in Autoimmune Bullous Diseases

Autoimmune blistering diseases are characterized by autoantibodies against structural adhesion proteins of the skin and mucous membranes. Extensive characterization of their autoantibody targets has improved understanding of pathogenesis and laid the basis for the study of antigens/epitopes diversification, a process termed epitope spreading (ES). In this review, we have reported and discussed ES phenomena in autoimmune bullous diseases and underlined their functional role in disease pathogenesis. A functional ES has been proposed: (1) in bullous pemphigoid patients and correlates with the initial phase of the disease, (2) in pemphigus vulgaris patients with mucosal involvement during the clinical transition to a mucocutaneous form, (3) in endemic pemphigus foliaceus, underlining its role in disease pathogenesis, and (4) in numerous cases of disease transition associated with an intermolecular diversification of immune response. All these findings could give useful information to better understand autoimmune disease pathogenesis and to design antigen/epitope specific therapeutic approaches.

Serological diagnostics in the detection of IgG autoantibodies against human collagen VII in epidermolysis bullosa acquisita: a multicentre analysis

BACKGROUND

Epidermolysis bullosa acquisita (EBA) is a rare, potentially devastating autoimmune disease of the skin. IgG autoantibodies directed against type VII collagen (Col7), the major component of anchoring fibrils, induce skin fragility leading to cutaneous and mucocutaneous blister formation, which is mostly of a scarring phenotype. Thus, powerful and reproducible diagnostic assays are critical to establish the diagnosis of EBA early to avoid irreversible sequelae.

OBJECTIVES

The present international, retrospective multicentre study included a large cohort of patients with EBA and evaluated the diagnostic power of four different diagnostic assays for the detection of anti-Col7 IgG autoantibodies.

METHODS

Overall, 95 EBA sera and 200 control sera consisting of 100 bullous pemphigoid sera, 50 pemphigus vulgaris sera and 50 sera of healthy controls were tested for anti-Col7 IgG autoantibodies using indirect immunofluorescence (IIF), two commercial enzyme-linked immunosorbent assay (ELISA) systems and Western blot (WB) analysis. EBA sera were taken from patients with positive direct immunofluorescence and IgG reactivity in at least one of the immunoserological assays (IIF, ELISA, WB).

RESULTS

A Col7-NC1/NC2 ELISA (MBL, Nagoya, Japan) showed the highest sensitivity (97·9%), followed by a Col7-NC1 ELISA (Euroimmun, Lübeck, Germany) (89·5%), WB with Col7-NC1 (85·3%), and IIF on saline-split human skin (74·7%). The specificities of both ELISA systems were comparable (NC1 98·7%, NC1/NC2 99·3%). Furthermore, WB was more sensitive than IIF, which was more specific.

CONCLUSIONS

The two commercially available ELISA systems allow for a highly sensitive and specific diagnosis of EBA. The sensitivity of the Col7-NC1/NC2 ELISA is significantly higher compared with the ELISA based on the Col7-NC1 domain only.

Immunofluorescence of Autoimmune Bullous Diseases

Autoimmmune bullous diseases of skin and mucosa are uncommon, disabling, and potentially lethal diseases. For a quick and reliable diagnosis immunofluorescence is essential. This article describes two variants of immunofluorescence. The direct method uses a skin or mucosal biopsy of the patient to detect in vivo bound antibodies. Indirect immunofluorescence uses patient's serum and a substrate to visualize circulating autoantibodies. These two methods supplemented with advanced techniques allow reliable classification of autoimmune bullous diseases; not only the main entities pemphigus and pemphigoid, but also subclasses within these groups. This is important because prognosis and therapy vary among different variants of autoimmune bullous diseases.

Clinical features and diagnosis of epidermolysis bullosa acquisita

INTRODUCTION

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune blistering disease of skin and mucous membranes. EBA is caused by autoantibodies against type VII collagen, which is a major component of anchoring fibrils, attaching epidermis to dermis. Binding of autoantibodies to type VII collagen leads to skin fragility and, finally, blister formation. The clinical picture of EBA is polymorphic, with several distinct phenotypes being described. Despite recent progress in understanding the pathophysiology of EBA, its diagnosis is still challenging. Areas covered: This review provides an update on the clinical manifestations and diagnostic methods of EBA. We searched PubMed using the terms 'epidermolysis bullosa acquisita' covering articles in English between 1 January 2005 and 31 May 2016. Relevant older publications were retrieved form cited literature. Expert commentary: While the clinical picture is highly variable, diagnosis relies on direct immunofluorescence (IF) microscopy of a perilesional skin biopsy. Linear deposits of IgG, IgA and/or C3 along the dermal-epidermal junction with an u-serrated pattern are diagnostic for EBA alike the detection of serum autoantibodies against type VII collagen. Several test systems for the serological diagnosis of EBA have recently become widely available. In some patients, sophisticated diagnostic approaches only available in specialized centers are required.

Autoimmune bullous diseases associations

The presence of one autoimmune disorder helps lead to the discovery of other autoimmune conditions. It is thought that diseases in which autoimmunity is a feature tend to be associated together more often than one can ascribe to chance. A variety of diseases have been implicated in the onset of intraepidermal and subepidermal autoimmune diseases. The presence of one autoimmune disease should alert the physician to watch for a second immunologic disorder. A list of autoimmune bullous diseases associations includes autoimmune bullous diseases, pemphigus, pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis (Duhring), linear immunoglobulin A disease, and multiple autoimmune syndrome.

Epidermolysis bullosa acquisita

Epidermolysis bullosa acquisita (EBA) is a rare, acquired, chronic subepidermal bullous disease of the skin and mucosa characterized by autoantibodies to type VII collagen (C7) structures, a major component of anchoring fibrils, which attach the epidermis to the dermis. EBA patients have tissue-bound and circulating antitype C7 autoantibodies that attack type C7 and result in a reduction or perturbation of normally functioning anchoring fibrils. Patients with EBA have skin fragility, blisters, erosions, scars, milia, and nail loss, all features reminiscent of genetic dystrophic epidermolysis bullosa. These immunoglobulin G antitype C7 antibodies are pathogenic, because when they are injected into mice, the mice develop an EBA-like blistering disease. In addition to the classical mechanobullous presentation, EBA also has several other distinct clinical syndromes similar to bullous pemphigoid, Brunsting-Perry pemphigoid, or cicatricial pemphigoid. Although treatment for EBA is often unsatisfactory, some therapeutic success has been achieved with colchicine, dapsone, plasmapheresis, photopheresis, infliximab, and intravenous immunoglobulin.

Genetic elimination of α3(IV) collagen fails to rescue anti-collagen B cells

Organ deposition of autoantibodies against the noncollagenous-1 domain of the α3 chain of type IV collagen leads to severe kidney and lung injury in anti-glomerular basement membrane disease. The origin and regulation of these highly pathogenic autoantibodies remains unknown. Anti-α3(IV) collagen B lymphocytes are predicted to mature in vivo ignorant of target antigen because α3(IV) collagen expression is highly tissue restricted and pathogenic epitopes are cryptic. However, a recent analysis of an anti-α3(IV)NC1 collagen autoantibody transgenic mouse model revealed that developing B cells are rapidly silenced by deletion and editing in the bone marrow. To dissect the role of collagen as central tolerogen in this model, we determined B cell fate in autoantibody transgenic mice genetically lacking α3(IV) collagen. We found that absence of the tissue target autoantigen has little impact on the fate of anti-α3(IV)NC1 B cells. This implies a more complex regulatory mechanism for preventing anti-glomerular basement membrane disease than has been previously considered, including the possibility that a second antigen present in bone marrow engages and tolerizes anti-α3(IV)NC1 collagen B cells.

Autoimmune bullous diseases in Austria

Autoimmune bullous diseases (AIBD) are chronic disorders associated with significant morbidity and even mortality, for which the 19 dermatologic departments in Austria apply standard modalities to provide state-of-the-art diagnosis and treatment. Most of the affected individuals are initially treated on an inpatient basis, with follow-up done in specialized outpatient clinics or in private practices. A well-established system of care for AIBD patients is thus available nationwide. Considering the significant morbidity and mortality but also rareness of AIBD, national and international standardization of AIBD administration in registries is a major requirement of further improvement in patient care.

Approach to the patient with autoimmune mucocutaneous blistering diseases

Autoimmune mucocutaneous blistering diseases (AMBD) are a rare group of dermatoses that can be potentially fatal. There are many subtypes and their clinical presentation can vary from being localized to general involvement. It is crucial that a diagnosis be made as early as possible and appropriate treatments are implemented. This article will discuss the diagnosis and available treatments of the major AMBDs. There are very few case-controlled studies regarding the treatments of these diseases. Most of the treatments used for these diseases are based on anecdotal reports. Hence, a synopsis of the conventional treatments and some brief recommendations will also be discussed. A brief discussion regarding "rescue" therapies that have been used for those patients with more recalcitrant cases of AMBD will also be presented.

Erosive diseases of the vulva

Vesicobullous and inflammatory diseases produce vulvar erosions that may exhibit nonspecific morphology and represent a diagnostic challenge. An approach to arriving at the correct diagnosis is presented. Most common etiologies are reviewed.

[Successful use of combined corticosteroids and rituximab in the treatment of recalcitrant epidermolysis bullosa acquisita]

BACKGROUND

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune subepidermal blistering disease; it is potentially serious and is often refractory to conventional treatments, including corticosteroids. We report a new case of successful treatment of EBA using rituximab (anti-CD20 antibody) without relapse after 1 year of follow-up.

CASE REPORT

A 76-year-old man was seen for blisters of the skin and mucosa, atrophic scars and milia on areas of friction. The diagnosis of EBA was made on the basis of histological and immunohistochemical criteria. The patient was unsuccessfully treated with topical steroids, dapsone, topical tacrolimus, systemic steroids, mycophenolate mofetil, doxycycline and methotrexate. Four weekly infusions of rituximab of 375 mg/m(2) body area were performed, combined with systemic steroids: they proved beneficial within 3 weeks, with a noticeable improvement and no further blisters at 7 months. After 1 year of follow-up, the skin disease is still stable with 5 mg/day of prednisone alone being given.

DISCUSSION

This is the eighth reported case of treatment of EBA with rituximab and the sixth successful therapeutic outcome, with good steroid sparing effect and undeniable improvement in quality of life within several months and good tolerability at 12 months of follow-up. This treatment may be proposed early in cases of EBA refractory to conventional treatments. However, clinical observation is necessary to study potential long-term adverse effects.

IgG from patients with bullous pemphigoid depletes cultured keratinocytes of the 180-kDa bullous pemphigoid antigen (type XVII collagen) and weakens cell attachment

We have shown that binding of bullous pemphigoid (BP)-patient IgG (BP-IgG) causes the internalization of BP180 from the cell membrane. This study examined whether BP-IgG treatment can deplete cultured keratinocytes of BP180, how it affects cellular levels of alpha6 and beta4 integrins (by western blot analysis using monoclonal antibodies to these antigens), and whether it reduces adhesion of cells to the culture dish (by a vibration detachment assay). All BP-IgG or BP sera with high values of BP180-ELISA from 18 BP patients before and after oral corticosteroid treatment showed dramatically decreased BP180 in cells after 6 hours of BP-IgG stimulation, whereas alpha6 and beta4 integrin levels were not decreased. Even IgG from patients in whom oral corticosteroid had suppressed active blistering could deplete cells of BP180, as long as sera retained a high value of BP180-ELISA. On the other hand, reduction of cell BP180 content increased detachment of cells from the dish. These results suggest that BP-IgG reduces hemidesmosomal BP180 content, weakening the adhesion of hemidesmosomes to the lamina densa. In the presence of BP180 deficiency, inflammation generated by BP180 immune-complex formation might then tear the weakened lamina lucida, and this could lead to generation of the BP-specific split at the lamina lucida.

Lupus bulleux. À propos d'un cas

Bullous lupus is a rare manifestation of systemic lupus characterized by subepidermal blistering. We report a case of a-27-year-old woman with vesiculobullous lesions and class IV lupus nephritis. Bullous lupus is often associated with autoimmunity to type VII collagen.

Métodos diagnósticos en las enfermedades ampollosas subepidérmicas autoinmunes

There is considerable clinical and histological overlap among the subepidermal autoimmune bullous diseases. The knowledge at the molecular level of the dermo-epidermal junction is essential to understand this group of diseases. The immune-based techniques have contributed to increase the knowledge of these entities and have been progressively incorporated into clinical practice. In this review of the diagnostic methods of subepidermal autoimmune bullous diseases we summarize the most recent advances on the molecular biology of the dermo-epidermal junction, focusing on the immune-based diagnostic techniques. We distinguish two main groups of diagnostic methods: those that detect autoimmune deposits in the skin (direct immunofluorescence and its variants including confocal microscopy) and those that detect antibodies in serum or in other fluids (indirect immunofluorescence and its variants, ELISA, immunoblot and immunoprecipitation). We explain the methodology and diagnostic keys of the techniques most widely applied in our milieu.

Subepidermal blistering disorders: a clinical and histopathologic review

The subepidermal blistering disorders are comprised of a number of unrelated disorders with a diverse clinical presentation and pathogenic basis that share in common the presence of blister formation beneath the epidermis. Many of the disorders are both debilitating and potentially fatal. Timely and accurate diagnosis facilitates their appropriate management. The etiologic, clinical, and pathologic attributes as well as the treatment of these disorders including bullous pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis, linear IgA dermatosis, cicatricial pemphigold, herpes gestationis,and porphyria cutanea tarda are described.

Vesiculobullous systemic lupus erythematosus: a case with circulating IgG and IgA autoantibodies to type VII collagen

We report a case of a 17-year-old Japanese boy with vesiculobullous systemic lupus erythematosus. He had a facial "butterfly" erythema and blistering eruption develop. Antinuclear, RNP, and Sm antibodies were positive. The American Rheumatism Association criteria for a diagnosis of systemic lupus erythematosus were met. A skin biopsy specimen showed papillary microabscesses of neutrophils and subepidermal blisters and deposits of IgG, IgA, IgM, and C3 by direct immunofluorescence. Indirect immunofluorescence on salt-split skin showed linear IgG, IgA, and C3 deposits on the dermal side. IgG and IgA autoantibodies in his serum reacted with the 290-kd proteins of type VII collagen from human dermal extracts and the recombinant fusion proteins from the noncollagenous domain of type VII collagen by Western immunoblot. To our knowledge, this is the first report of vesiculobullous systemic lupus erythematosus with circulating IgG and IgA autoantibodies to type VII collagen.

Anti-p200 pemphigoid: diagnosis and treatment of a case presenting as an inflammatory subepidermal blistering disease

Anti-p200 pemphigoid is a recently defined subepidermal immunobullous disease. It is characterized by the binding of circulating IgG autoantibodies to the dermal side of 1 M NaCl split skin and by reactivity of these autoantibodies to a unique 200-kd antigen on immunoblot of dermal extract. On immunoelectron microscopic examination, these autoantibodies deposit at the lamina lucida-lamina densa interface. We describe the clinical, histologic, and immunopathologic features in a patient with anti-p200 pemphigoid, as well as his favorable response to treatment with systemic glucocorticosteroids and dapsone.

Cicatricial pemphigoid

Cicatricial pemphigoid (CP) is a heterogeneous group of rare, chronic, subepithelial blistering disorders of the mucous membranes and, occasionally, the skin, which can have serious and rarely fatal consequences. The most common clinical features are desquamative gingivitis, oral erosions, and conjunctival fibrosis. Skin lesions occur less frequently and may present as widespread vesicles and bullae, as in bullous pemphigoid (BP). In some patients, the scarring can be a source of significant morbidity because it can result in odynophagia, strictures of the upper aerodigestive tract, or corneal opacities leading to eventual blindness. This article is a comprehensive review and discusses clinical, pathologic, and pathophysiologic aspects of this group of disorders collectively known as CP. (J Am Acad Dermatol 2000;43:571-91.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be familiar with the clinical spectrum of CP, the histopathologic and immunopathologic characteristics, the differential diagnosis, the treatment, and the natural history of the disease. Furthermore, this learning activity should facilitate early diagnosis of CP and should promote the idea that the involvement of other specialists, including ophthalmologists, otolaryngologists, gastroenterologists, and oral medicine specialists, as appropriate, will aid in providing these patients with the highest quality of care.

A subepidermal bullous eruption associated with IgG autoantibodies to a 200 kd dermal antigen: the first case report from the United States

We describe an 81-year-old white man in whom a subepidermal bullous eruption developed that clinically resembled bullous pemphigoid. The eruption promptly responded to oral tetracycline and niacinamide and topical clobetasol. Histologic examination of perilesional skin revealed neutrophilic infiltration with formation of papillary microabscesses and subepidermal cleavage. Direct immunofluorescence showed linear deposition of IgG and C3 along the basement membrane zone. By indirect immunofluorescence, circulating IgG autoantibodies bound exclusively to the dermal side of salt-split normal human skin. Immunoblot analysis demonstrated that the patient's autoantibodies reacted with a 200 kd dermal protein that was different from type VII collagen, the epidermolysis bullosa acquisita autoantigen. This patient represents the first confirmed case from the United States with a recently reported novel autoimmune subepidermal bullous disease associated with IgG autoantibodies to a 200 kd dermal antigen.

When to request immunofluorescence: practical hints

This review highlights important considerations in obtaining good skin biopsy specimens to optimize results of direct immunofluorescence (IF) studies and also summarizes the various patterns of cutaneous IF deposition and their associated diagnoses. IF findings of immunobullous diseases, lupus erythematosus, vasculitis, lichen planus, and erythema multiforme are included. The uses of indirect IF studies are also reviewed including newer modifications that are valuable in helping to diagnose epidermolysis bullosa acquisita and paraneoplastic pemphigus.

The blistering diseases

The intent and purpose of the authors is to familiarize the reader with the principles that govern the diagnosis and management of autoimmune mucocutaneous blistering diseases. The purpose was not to be all-inclusive but illustrative. There are several other blistering diseases that have not been discussed because of the limited scope of this article. Of these, toxic epidermal necrolysis, erythema multiforme, and the like warrant the same attention and early recognition. These are covered in different articles. For the same reasons, certain genetically linked blistering diseases have not been discussed.

Mucocutaneous features of autoimmune blistering diseases

This review will describe adult onset mucocutaneous/autoimmune diseases that involve defects in cell-to-cell, cell-to-matrix, or cell-to-basement membrane adhesion. Included in this group are pemphigus, cicatricial pemphigoid, linear IgA bullous dermatosis, epidermolysis bullosa acquisita, and bullous systemic lupus erythematous. Detection and treatment of blistering disorders that manifest early in the oral cavity may prevent widespread involvement of skin. During the past few years, targets of autoantibodies have been clarified and new targets have been identified, allowing better understanding of the pathophysiology involved in these diseases. New information about more effective regimens with fewer side effects has also been obtained, presenting new treatment options. Clinical manifestations and management of these disorders will be described as well as histopathologic, ultrastructural, and immunopathologic studies that distinguish each disorder and facilitate diagnosis and treatment.

Fibulin-2 binds to the short arms of laminin-5 and laminin-1 via conserved amino acid sequences

Epithelial cell-specific laminin-5, consisting of three chains, alpha3, beta3, and gamma2, is a component of the anchoring filament that traverses the lamina lucida beneath the hemidesmosomes of epidermal cells and functions to link these cells to the basement membrane. We have studied the molecular interaction between laminin-5 and extracellular matrix proteins using recombinant proteins and synthetic peptides. Affinity chromatography assays with recombinant fragments of the laminin gamma2 short arm identified a 195-kDa binding protein in the conditioned media from the mouse epidermal cell line Pam 212 and from primary dermal fibroblasts. This molecule was identified by Western blotting as fibulin-2, a recently identified extracellular matrix protein. Using deletion mutants and various synthetic peptides in competition assays, the 9-amino acid sequence SADFSVHKI (residues 199-207) in domain IV of the gamma2 chain was defined as a critical site for fibulin-2 binding. An anti-gamma2 antibody co-immunoprecipitated fibulin-2 from the conditioned media, further confirming the interaction of fibulin-2 with laminin-5. Fibulin-2 was also found to interact with laminin-1 (alpha1beta1gamma1) through a region (residues 654-665) of the alpha1 chain short arm whose sequence is similar to that of the fibulin-2 binding site of the gamma2 chain. Together these results suggest that fibulin-2 functions to bridge laminin-1 and laminin-5 with other extracellular matrix proteins, providing a linkage between the cell surface and the basement membrane.

Eosinophilic and neutrophilic spongiosis: clues to the diagnosis of immunobullous diseases and other inflammatory disorders

When eosinophils or neutrophils are found within the epidermis in concert with edema, the pattern is known as eosinophilic or neutrophilic spongiosis. Although eosinophilic spongiosis has been accepted as a clue to the diagnosis of blistering disorders for some time, the fact that either pattern can serve as a clue to the diagnosis of a variety of disorders, including immunobullous diseases, is less widely known. Herein, we review the types of inflammatory skin diseases, including spongiotic dermatitides, subepidermal vesicular dermatitides, intraepidermal vesicular dermatitides, and perivascular or diffuse dermatitides, that display intraepidermal eosinophils and neutrophils. We also review the known mechanisms that explain in part why intraepidermal granulocytes are commonly found in this diverse group of skin diseases.

Localized linear bullous eruption of systemic lupus erythematosus in a child

A 9-year-old girl newly diagnosed with systemic lupus erythematosus (SLE) developed a localized linear papulovesicular eruption over the right dorsal hand and ulnar forearm. The skin findings were clinically suggestive of herpes zoster, lichen striatus, or lichen planus-lupus erythematosus overlap. However, histologic, immunofluorescent, immunoelectron microscopic, and immunoblot studies revealed findings compatible with bullous SLE. Our patient is noteworthy because she is the first one reported with bullous SLE presenting in a localized linear pattern. She is also the second-youngest reported patient with bullous SLE.