DR [Dermatology Reports 2011; 3:e38] [page 83] Epidermolysis bullosa acquisita: current diagnosis and therapy Christine R. Mehren,1 Robert Gniadecki2 1Department of Dermatology, Bispebjerg Hospital, Copenhagen; 2University of Copenhagen, Bispebjerg Hospital, Denmark Abstract Epidermolysis bullosa acquisita (EBA) is an acquired, autoimmune subepidermal blister- ing disease with an approximate prevalence of 0,2/million people. The hallmark of EBA is the presence of autoantibodies (mainly IgG class) to anchoring fibril collagen (type VII collagen) located at the dermal-epidermal junction. Clinically EBA is subdivided into the inflamma- tory and the non-inflammatory phenotypes, depending on the level of the cleavage in the basal membrane. A recent addition to the diag- nostic techniques is the analysis of the serra- tion pattern of the autoantibody deposits at the basal membrane in the direct immunofluores- cence. EBA and the closely related bullous sys- temic lupus erythematosus are the only dis- eases presenting with the so-called u-serration pattern which distinguishes them from many other autoimmune subepidermal blistering diseases. We also discuss the recent advances in therapy, including the experience with Rituximab. Clinical features Epidermolysis bullosa acquisita (EBA) was described for a century ago by Ellliot.1 It is a rare disease with an approximate prevalence of 0.2/million people.2 EBA is an acquired, autoimmune cutaneous subepidermal blister- ing disease that primarily involves the skin, and sometimes mucous membranes. There is no racial or gender predilection. EBA often presents in the fourth to fifth decades of life. The hallmark of EBA is the presence of autoan- tibodies (mainly IgG class) to type VII collagen, a major component of anchoring fibrils at the dermal-epidermal junction. The disease occurs in approximately 5% of unselected patients with basement membrane zone antibodies.3 The blister-inducing potential of autoantibod- ies to type VII collagen have been shown by demonstrating their capacity to trigger an Fcγ- dependent inflammation leading to split for- mation in cryosections of human skin.4 Clinically EBA is subdivided into two clinical types: the inflammatory and the non-inflam- matory phenotype.5 Patients with the non- inflammatory form of EBA (the classical EBA type) have increased skin fragility with subse- quent formation of blisters or erosions on the trauma-prone areas of the skin, such as exten- sor surfaces of elbows, knees, ankles, and but- tocks. Tense vesicles and bullae appear on non- inflamed skin or scarred skin. Nail dystrophy and scarring alopecia have been observed in some patients with the classical EBA. The inflammatory form of EBA can mimic almost all other chronic bullous diseases, and its clinical differentiation from bullous pemphigoid, mucous membrane pemphigoid and linear IgA bullous dermatosis may be difficult.6 It pres- ents with widespread, tense vesicles and bul- lae and is not localized to trauma-prone sites and generally heals with minimal scarring and milia formation. Progressive and recurrent disease in the mucosal tissues can result in irreversible complications similar to those seen in mucous membrane pemphigoid (MMP) including blindness and oesophageal strictures.7 By electron microscopy, the cleav- age plane can be seen within the lamina lucida or sub-lamina densa regions of the dermal-epi- dermal junction. If the cleavage is within the lamina lucida, it is associated with the pres- ence of an inflammatory infiltrate rich in poly- morphonuclear neutrophils.8 The deeper level of split in the non-inflammatory EBA type may explain why it usually heals with significant scar and milia formation, which is only rarely observed in the inflammatory type (Table 1). Diagnostic techniques The first diagnostic criteria for EBA were established in the early 1970s by Roenigk and associates. They were i) spontaneous or trau- ma-induced blisters resembling hereditary dystrophic EB, ii) adult onset, iii) a negative family history for EB, and iv) the exclusion of all other bullous diseases.17 However, since then at least 33 verified cases of childhood EBA have been reported in the literature, mainly of the inflammatory subtype.18 In addition a diag- nosis of EBA cannot be done reliably solely by clinical findings, because of the variable clini- cal and histological presentations. Immunofluorescence techniques remains the cornerstone of the diagnosis of EBA and have increasingly replaced the immunoelec- tron microscopy (IEM) as the gold standard.19 Other investigative diagnostic techniques are immunoblotting, ELISA, and immunoprecipita- tion. Direct Immunofluorescence (DIF) on per- ilesional skin demonstrates linear immune deposits of immunoreactants, mainly IgG, at the basement membrane zone. However deposits of IgA, IgM, C3, C4, or properdin may be detected as well. In EBA depositions of IgG in the absence of C3 is seen more commonly than in BP. Furthermore, deposits of multiple conjugates (including IgG, IgA, IgM, C3, C4, or properdin) are seen more frequently in the set- ting of EBA.7 Indirect immunofluorescence (IIF) can detect the presence of circulating IgG autoantibodies, directed against type VII colla- gen in the basement membrane, it usually detects the IgG autoantibodies that binds to the dermal floor on salt split skin. Salt split skin substrate can be used to distinguish EBA and bullous pemphigoid (BP), because IgG autoantibodies from patients with bullous pemphigoid bind to the epidermal roof (upper part) of salt-split skin. If the antibody labels the dermal side of the separation, the patient usually has either EBA or bullous SLE (there are, however, other diseases with dermal staining; anti-epiligrin (lamina-5), Cicatricial pemphigoid, Chan’s disease, Zilliken’s disease and Ghohestani’s disease).19 A breakthrough in the diagnostics was the observation of specific serration patterns in the autoantibody deposits at the basement membrane in direct immunofluorescence. Besides a true linear staining pattern, two DIF immunodeposition patterns have been described i) a u-serrated staining pattern is typical of EBA, and ii) an n-serrated staining pattern in other subepidermal immunobullous diseases.9 The binding of autoantibodies in EBA to type VII collagen, can ultrastructurally be seen as upstanding arms between the rootlets of the basal keratinocytes, resulting in u shapes. Consequently these two distinct pat- terns can be applied in order to differentiate EBA from other pemphigoid variants by DIF only. The type of serration in the case of IgA and IgG is similar, however, in the case of IgA it is more easily recognized due to better fluo- rescence image contrast. Diseases such as IgA-mediated EBA and inflammatory EBA may look like BP, however, using the serration pat- terns algorithm, patients with EBA who other- wise would have been erroneously diagnosed can be detected. Immunoelectron microscopy (IEM) docu- ments the localization of the immune deposits within the dermal-epidermal junction of the skin of EBA patients. By direct immunoelec- Dermatology Reports 2011; volume 3:e38 Correspondence: Christine R. Mehren, Depart- ment of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark. E-mail: c_mehren@hotmail.com Key words: bullous pemphigoid, epidermolysis bullosa, serration pattern, immunofluorescence. Received for publication: 14 April 2011. Accepted for publication: 9 August 2011. This work is licensed under a Creative Commons Attribution NonCommercial 3.0 License (CC BY- NC 3.0). ©Copyright C.R. Mehren and R. Gniadecki., 2011 Licensee PAGEPress, Italy Dermatology Reports 2011; 3:e38 doi:10.4081/dr.2011.e38 No n- co mm er cia l u se on ly [page 84] [Dermatology Reports 2011; 3:e38] Review Table 1. Comparison of the clinical and immunopathological features of subepidermal blistering diseases. Subepidermal immunobullous Clinical Characteristic DIF Binding on Serration disease features salt split skin pattern Bullous Elderly, most common autoimmune blistering IgG and C3 or C3 alone (± Epidermal n-serrated9 pemphigoid (BP) disease. Tense blisters on inflammed or non weaker staining IgM, IgA) at (few dermal) inflamed skin. Pruritus common, variable the dermal-epidermal junction. severity. More common in patients with multiple sclerosis. Predilection sites: the inner or anterior thighs, groins, flexor surfaces of the upper extremities and lower abdomen. Oral mucosal lesions are rare. Pemphigoid During pregnancy and/or puerperium; urticarial Linear deposition of C3 Epidermal As BP; gestationis plaques and/or tense blisters. Pruritus typically ± IgG at the dermal- n-serrated severe. epidermal junction. Predilection sites: umbilical and periumbilical regions; trunk and extremities. Lichen planus Usually benign, tense blisters and lesions of Linear deposits of IgG at the Epidermal Unknown pemphigoides lichen planus (usually persistent) on top of dermal-epidermal lichen planus lesions or on clinically normal skin. junction. Predilection sites: the extremities, trunk and oral mucosa. Mucous membrane Elderly (female) patients. In anti-BP180 MMP and Epidermal in n-serrated9 pemphigoid Tense blisters and erosions with scar antilamin 332 MMP10: linear anti-BP 180 MMP formation. IgG, ±C3 occasionally IgA. and ocular MMP Predilection sites: mucosa of the mouth, eyes, nose, larynx, eosohagus or anogenital In ocular MMP:11 linear Dermal in antilamin regions. IgA ±IgG. 332 MMP Dermatitis herpetiformis Adult patients. Erythematous papules, Granular papillary and Negative Irrelevant urticarial plaques, papulovesicles, vesicles and basement membrane IgA. rarely bullae, isolated or in herpetiform grouping often healing with scar formation. Intensely pruritic. Predilection sites: symmetrically distributed lesions on extensor surface of the extremities, scalp, nape, shoulders, sacral region and buttocks. Linear IgA disease Papulovesicular eruption in cluster of jewels Linear IgA (rarerly granular) at Epidermal n-serrated9 configuration. Pruritic the dermal-epidermal junction. (few dermal) (ranging from mild to severe). Predilection sites: trunk, extremitites, the face, abdomen and perineum. Frequent mucous membrane involvement (may induce severe complications). Linear IgA/IgG bullous dermatosis12 Resemble the lesions of BP, annular vesicobullous Linear IgA and IgG ± C3 at the Epidermal (few Probably lesions with frequent involvement of the oral dermal-epidermal junction. dermal or both n-serrated mucosa. epidermal and dermal) Predilection sites: no specific Anti-p450-pemphigoid13 Only one case in literature, Fujiwara et al.14 Only one case in literature, Epidermal13 Unknown Fujiwara et al.14 Anti-p200 pemphigoid32 Often resembles BP, could resemble dermatitis Linear IgG and C3 at the dermal- Dermal n-serrated9 herpetiformis, linear IgA disease or EBA. Could epidermal junction. involve mucous membranes. Often coexisting psoriasis. (rapid response to treatment) Epidermolysis bullosa acquisita Classical EBA: skin fragility, trauma- induced Linear IgG (± IgA, IgM), C3 Dermal u-serrated9 blisters and erosions. at the dermal-epidermal Predilection sites: extensor surfaces of the junction. extremities. ± mucous membrane lesion. Inflammatory EBA: widespread eruptions of tense blisters on erythematous or normal appearing skin. Predilection sites: usually on flexural and/or intertriginous areas. ± mucous membrane lesions Bullous SLE Mainly adult patients. Tense blisters on normal or Linear or granular depositions Dermal (rarely u-serrated9 erythematous skin, eruptions usually in a of IgG (± IgM, IgA, C3) at the epidermal or herpetiform arrangement in patients with SLE. dermal-epidermal junction. combined binding) Pruritus may be severe. Predilection sites: trunk and flexural surfaces. Frequently oral lesions. Anti-p105-pemphigoid16 Bullae and erosions on mucous membrane and Linear IgG and C3 deposition Dermal13 Unknown skin, resembling toxic epidermal necrolysis or at the skin basement pemphigus vulgaris13 membrane zone13 No n- co mm er cia l u se on ly [Dermatology Reports 2011; 3:e38] [page 85] tron microscopy the ultrastructural localization of in vivo-bound IgG autoantibodies at the basement membrane is documented. With indirect immunoelectron microscopy the bind- ing site of circulating IgG autoantibodies at the basement membrane is detected. IEM detects IgG autoantibodies at the lamina densa and sublamina densa areas of skin basement mem- brane. Bullous pemphigoid IgG autoantibodies, on the contrary, are localized to the hemi- desmosome and upper lamina lucida.20 Immunoblotting represents a sensitive detection method for EBA.21 EBA sera will bind to a 290-KDa band in Western blots of human skin basement membrane proteins containing type VII collagen, whereas sera from all other primary blistering diseases will not. This band corresponds to a single alpha chain of the type VII collagen homotrimer molecule.22 Western blotting differentiates between anti-p200 pem- phigoid and EBA. To distinguish between the latter two disorders, patients’ sera have to be subjected to Western blotting of extract from human dermis and then react with 200 and 290 kDa proteins in antip-200 pemphigoid and EBA, respectively.2 ELISA (Enzyme-linked immunosorbent assay) documents the specific basement mem- brane antigen recognized by the patient's IgG circulating autoantibodies. The ELISA method identifies non-denaturated, nonreduced pro- teins and is more sensitive than immunoblot- ting, which only detects denatured, reduced proteins.7 Treatment Compared with other autoimmune blister- ing diseases, EBA has a decreased responsive- ness to therapy. Inflammatory EBA, EBA pre- senting in children and IgA-EBA, respond more favourably to the conventional treatment approach of high-dose corticosteroids and cor- ticosteroid sparing agents. In most cases of IgA-EBA, the skin lesions respond to therapy with dapsone alone. Dapsone and low-dose prednisone are usu- ally effective in treating childhood EBA.18 However, high doses of corticosteroids are not recommended as maintenance therapies as the adverse effects of corticosteroids are both time and dose dependent. Non-inflammatory (classical) EBA is often refractory to systemic corticosteroids, azathio- prine, methotrexate, and cyclophosphamide.23 Therapeutic options that have proven effective in retrospective observations include extracor- poreal photochemotherapy (ECP), i.v. immu- noglobulin (IVIG), and Rituximab. The treatment of EBA patients with IVIG has shown encouraging results. In one retrospec- tive analysis two patients with severe EBA were treated with monthly cycles of IVIG. One of the patients had a complete response, defined as absence of lesions for more than 4 weeks without any treatment. The other patient responded to the treatment, however, due to metastatic lung cancer the treatment was discontinued.24 Another case describes a patient treated with 6 cycles of IVIG at a dose of 400 mg/kg per day for 5 consecutive days (repeating the cycle every 4 weeks). After the second cycle, most of the erosions had healed and marked remission was observed during the 6-month follow-up period. The patient did not experience any negative side effects.25 Patients that have had unsatisfactory response to steroid, immunosuppressive agents and IVIG may benefit from the therapy with rituximab. This monoclonal antibody reacting against CD20 depletes mature, autoreactive B-cells. Of the reported cases of EBA patients treated with rituximab, either complete remission or very good partial remis- sions have been reported. In one retrospective analysis the patient, a 58-year old woman, had to be hospitalized due to the severity of EBA. She had extensive cutaneous and oral ulcera- tion, cellulitis and a deep vein thrombosis sec- ondary to immobility. After four rituximab infusions at a dose of 375 mg m-2, she experienced complete remis- sion.26 Another patient, a 54-year-old woman experienced a partial remission within a month after the onset of rituximab. After twelve rituximab infusions at a dose of 375 mg m-2, she experienced almost complete cuta- neous clearance with improved oral intake and mobility.27 Rituximab can safely be combined with high-dose IVIG, which may exert a syner- gistic effect and simultaneously protect against serious infection-related adverse events.28,29 Long-term ECP has been reported to induce remission in three patients with drug resist- ant, aggressive cases of EBA.30 ECP is based on separation of a leukocyte/lymphocyte-enriched cell fraction from the peripheral blood, extra- corporeal treatment of the cells with 8- MOP/UVA, and subsequent reinfusion of the cells in the patient. The main effects in EBA seem to consist in inhibition of pathogenetic autoantibody production by B lymphocytes and generation of regulatory T cells. When treating a patient with EBA, it is important to be aware of coexisting systemic diseases that might influence the choice of therapy. Among the systemic diseases reported in association with EBA, are malignancies and autoimmune diseases.23 Inflammatory bowel disease (IBD) is one of the more common sys- temic illnesses associated with EBA; 25% of EBA patients have IBD.31 There are a few cases of EBA patients with coexisting psoriasis.32 Ultraviolet radiation is not a treatment option in this case as it has been demonstrated that it can induce blister- ing in patients with EBA.33 References 1. Elliott GT. Two cases of epidermolysis bul- losa. J Cutan Genitourin Dis 1895;13:108. 2. Ishii N, Hamada T, Dainichi T, et al. Epidermolysis bullosa acquisita; what’s new. J Dermatol 2010;37:220-30. 3. Zhu XJ, Niimi Y, Bystryn JC. Epidermolysis bullosa acquisita. Incidence in patients with basement membrane zone antibod- ies. Arch Dermatol 1990;126:171-4. 4. Sitaru C, Kromminga A, Hashimoto T, et al. Autoantibodies to type VII collagen medi- ate Fcgamma-dependent granulocyte acti- vation and induce dermal-epidermal sepa- ration in cryosections of human skin. Am J Pathol 2002;161:301-11. 5. Tanka H, Ishida, Yamamoto A, et al. A novel variant of aquired epidermolysis bul- losa with autoantibodies against the cen- tral triple-helical domain of type VII colla- gen. Lab Invest 1997;77:623-32. 6. Roengik HH, Ryan JG, Bergfeld WF. Epidermolysis bullosa acquisita. Report of three cases and review of all published cases. Arch Dermatol 1971;103:1-10. 7. Lehman JS, Camilleri MJ, Gibsom LE. Epidermolysis bullosa acquisita: concise review and practical considerations. Int J Dermatol 2009;48:227-36. 8. Mihai S, Sitaru C. Immunopathology and molecular diagnosis of autoimmune bul- lous diseases. J Cell Mol Med 2007;11:462- 81. 9. Vodegel RM, Jonkman MF, Pas HH, De Jong MC. U-serrated immunodeposition pattern differentiates type VII collagentar- geting bullous disease from other subepi- dermal bullous automimmune diseases. Br J Dermatol 2004;151:112-8. 10. Natsuga K, Nishie W, Shinkuma S, et al. Circulating IgA and IgE autoantibodies in antilaminin-332 mucous membrane pem- phigoid. Br J Dermatol 2010;162:513-7. 11. Smith EP, Taylor TB, Meyer LJ, Zone JJ. Identification of a basement membrane zone antigen reactive with circulating IgA antibody in ocular cicatricial pemphigoid. J Invest Dermatol 1993;101:619-23. 12. Shimizu S, Natsuga K, Shinkuma S, et al. Localized linear IgA/IgG dermatosis. Acta Derm Venereol 2010;90:621-4. 13. Georgi M, Jainta S, Bröcker EB, Zillikens D. Autoantigens of subepidermal bullous autoimmune dermatoses. Hautarzt 2001; 52:1079-89. 14. Fujiwara S, Shinkai H, Takayasu S, et al. A case of subepidermal blister disease asso- ciated with autoantibody against 450 kD protein. J Dermatol 1992;19:610-3. 15. 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Auto- immunity to type VII Collagen: Epidermol- ysis Bullosa Acquisita. Clin Rev Allerg Immunol 2007;33:78-84. 20. Vodegel RM, de Jong MC, Pas HH, Jonkman MF. IgA-mediated epidermolysis bullosa acquisita: Two cases and review of the literature. J Am Acad Dermatol 2002; 6:919-25. 21. Schmidt E, Zillikens D. Research in prac- tice: diagnosis of subepidermal autoim- mune bullous disorders. J Dtsch Dermatol Ges 2009;7:296-300. 22. Woodley DT, Briggaman RA, O'Keefe EJ, et al. Identification of the skin basement- membrane autoantigen in epidermolysis bullosa acquisita. N Engl J Med 1984; 310:1007-13. 23. Hallel-Halevy, Nadelman C, Chen M, Woodley DT. Epidermolysis bullosa acquisita: update and review. Clin Derma- tol 2001;19:712-8. 24. Sanli H, Akay BN, Ayyildiz E, et al. Remission of severe autoimmune bullous disorders induced by long-term extracor- poreal photochemotherapy. Transf Apheres Sci 2010;43:353-9. 25. Segura S, Iranzo P, Martínez-de Pablo I, et al. High-dose intravenous immunoglobu- lins for the treatment of autoimmune mucocutaneous blistering diseases: evalu- ation of its use in 19 cases. J Am Acad Dermatol 2007;56:960-7. 26. Gourgiotou K, Exadaklyou D, Aroni K, et al. Epidermolysis bullosa acquisita: treatment with intravenous immunoglobulins. J Eur Acad Dermatol Venereol 2002;16:77-80. 27. Crichlow SM, Mortimer NJ, Harman KE. A successful therapeutic trial of rituximab in the treatment of a patient with recalcitrant high-titre epidermolysis bullosa acquisita. Br J Dermatol 2007;156:194-6. 28. Saha M, Cutler T, Bhogal B, et al. Refrac- tory epidermolysis bullosa acquisita: suc- cessful treatment with rituximab. Clin Exp Dermatol 2009;34:e979-e980. 29. Peterson JD, Chan LS. Effectiveness and side effects of anti-CD20 therapy for autoantibody-mediated blistering skin diseases: A comprehensive survey of 71 consecutive patients from the Initial use to 2007. Ther Clin Risk Manag 2009; 5:1-7. 30. Schmidt E, Bröcker E-B, Goebeler M. Rituximab in treatment-resistant autoim- mune blistering skin disorders. Clin Rev Allerg Immunol 2008;34:56-64. 31. Chen M, O´Toole EA, Sanghavi J, et al. The epidermolysis bullosa acquisita antigen (Type VII Collagen) is present in human colon and patients with Chron’s disease have Autoantibodies to Type VII Collagen. J Invest Dermatol 2002;6:1059-64. 32. Kabashima R, Hino R, Bito T, et al. Epider- molysis bullosa acquisita associated with psoriasis. Acta Dermatol Venereol 2010; 90:314-6. 33. Jappe U, Zillikens D, Bonnekoh B, Gollnick H. Epidermolysis bullosa acquisita with ultraviolet radiation sensitivity. Br J Dermatol 2000;142:517-20. Review No n- co mm er cia l u se on ly