REVIEW Recent Progress in Studies on Autoantigens for Various Autoimmune Blistering Skin Diseases

Transcription

1 REVIEW Recent Progress in Studies on Autoantigens for Various Autoimmune Blistering Skin Diseases Takashi Hashimoto Department of Dermatology, School of Medicine, Keio University, Tokyo, Japan (Received for publication on August 7, 1995) Abstract. Autoimmune blistering skin diseases develop separation either between epidermal keratinocytes or dermo-epidermal junction. Recent studies have revealed that the autoantigens for these diseases are components of either the desmosome, the cell adhesion junction between keratinocytes, or the hemidesmo some complex, cell adhesion machinery at the dermo-epidermal junction. Thus, the major pemphigus antigens are desmogleins, one of desmosomal cadherins. Both the 230 kd and 180 kd bullous pemphigoid antigens are present in the hemidesmosome, and epidermal basement membrane zone-specific extracellular matrices, epiligrin and type VII collagen, are detected by sera of cicatricial pemphigoid and epidermolysis bullosa acquisita, respectively. Furthermore, animal model studies using newborn mice have revealed that these autoantibodies are really pathogenic and can induce blister formation by passive transfer into mice. Therefore, these skin diseases seem to be a typical model for various autoimmune diseases, for most of which the role of autoantibodies has not yet been revealed. (Keio J Med 44 (4): , December 1995) Key words: autoimmune bullous skin disease, bullous pemphigoid, desmosome, hemidesmosome, pemphigus Introduction To establish stable architecture of the epidermis, strong adhesion either between epidermal keratinocytes or at dermo-epidermal junction is critical (Fig 1). It is well known that, among the adhesive junctions between cells, such as the tight junction, the adherence junction, the gap junction and the desmosome, the most important machinery is considered to be the desmosome.1-4 As adhesive machinery at the dermo-epidermal junction, the hemidesmosome and the focal contact are known. Dermo-epidermal adhesion is maintained mainly by the hemidesmosome and the structures under the hemi desmosome.5-7 Below the hemidesmosome, anchoring filaments are seen in lamina lucida, which connect the epidermis to lamina densa. In the uppermost portion of the dermis anchoring fibrils are seen, which then bind to the interstitial collagen in the dermis. Keratin inter mediate filaments insert into attachment plaques of both the desmosome and the hemidesmosome. The inter mediate filaments also associate with nuclear envelop via molecules called lamins. Actin microfimaments associate with plasma membrane at the adherens junction and the focal contact. The patients with autoimmune blistering skin diseases carry autoantibodies reactive with the cell surface of epidermal keratinocytes or the epidermal basement membrane zone (BMZ) which cause detachment of the epidermal keratinocytes or the dermo-epidermal junction.8,9 One of the most common type of the disease caused by anti-keratinocyte cell surface antibodies is pemphigus, and another representative disease type is bullous pemphigoid which develops subepidermal blister formation. However, a number of new diseases of distinct entities have recently been identified. The well charac terized autoimmune blistering skin diseases, as well as their autoantigens, are summarized in Table 1. Accumulated evidence has revealed that the antigens for the autoantibodies in these diseases are the com ponents of either the desmosome, the cell adhesion Reprint requests to: Dr Takashi Hashimoto, Department of Dermatology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160, Japan 115

2 116 Hashimoto T: Autoimmunc Blistering Skin Diseases Fig 1 Schematic model of adhesive apparatus for keratinocytc-keratinocyte interaction and dermo-epidermal junction in the epidermis. Table 1 Classification of Autoimmunc Blistering Skin Diseases junction between keratinocytes, or the hemidesmosome complex, cell adhesion machinery at the dermo-epidermal junction. In this review, I first describe the structure and constituents of both the desmosome and the hemidesmo some, and then discuss on the relationships between these components and the antigens reacted by the auto antibodies in the sera of the patients with various auto immune blistering skin diseases. Structures and Constitutional Components of the Desmosome (Fig 2) The desmosome is one of the intercellular adhering junctions seen mainly in the epithelial tissues. 1-4 Inside of the plasma membrane at the desmosome, there are electron dense attachment plaques, where keratin inter mediate filaments insert. A number of glycosylated and non-glycosylated proteins have been identified as com ponents of the desmosome. As transmembrane glyco proteins, there are two distinct groups of proteins; ie desmoglein (Dsg)10,11 and desmocollin (Dsc),12,13 both

3 Keio J Med 1995, 44 (4): Fig 2 Constituents of the epidermal desmosome. Dsg1; desmoglein 1, PFA; PF antigen, Dsg3; desmoglein 3, PVA; PV antigen, Dsc; desmocollin, DP; desmoplakin, PG: plakoglobin, and IFAP300; intermediate filament associated protein 300. of which consist of three different isoforms and designated Dsg1-3 and Dsc1-3. These proteins have been shown to be members of cadherin supergene family and are now called desmosomal cadherins. These molecules are considered to play a direct role in the adhesion between keratinocytes via "homophilic binding". As cytoplasmic attachment plaque proteins, desmoplakins (DP) I/II14,15 and plakoglobin (PG)16 have been best characterized. DP is the most abundant plaque proteins, and several lines of evidence indicated that DP directly binds to keratin intermediate filaments through its C-terminal domain. PG is shown to bind to both Dsg1 and Dsg3, and suggested to regulate the adhesive activity of these transmembrane proteins. 17 As other desmosomal plaque proteins, band 6 protein, 18 desmocalmin,19 plectin,20 intermediate filament associated protein 300 (IFAP300)21 and desmoyokin22,23 are known. PG and band 6 protein have been shown to be members of "armadillo" super gene family.24 Structures and Constitutional Components of the Hemidesmosome (Fig 3) Connection between keratin intermediate filaments and the hemidesmosome in basal keratinocytes, anchori ng filaments and other macromolecules in lamina lucida,

4 118 Hashimoto T: Autoimmune Blistering Skin Diseases Fig 3 Overview of human cutaneous BMZ. and interaction between lamina densa and interstitial collagen fibers via anchoring fibrils in papillary dermis form a continuous unit that play an important role in the adhesion at dermo-epidermal junction (Fig 3).5-7 The major keratins in basal keratinocytes are keratins 5 and 14.25,26 Keratin intermediate filaments insert into electron dense plaques of the hemidesmosome. The hemidesmo some contains the 230 kd bullous pemphigoid (BP) anti gen (BP230)27-33 and HD134 as cytoplasmic plaque proteins, both of which are suggested to bind directly to intermediate filaments. At the hemidesmosome, there are two transmembrane proteins, the 180 kd BP antigen (BP180)28,29,35-39 and ƒ 6ƒÀ4 integrin.40 The extracellular domains of BP180 and ƒ 6ƒÀ4 integrin extend into lamina lucida where anchoring filaments are located. Proteins associated with anchoring filaments include kalinin/ nicein/epiligrin (also called laminin 5),41,42 K-laminin (laminin 6),43 and 19-DEJ-1 antigen (uncein). Other constituents of lamina lucida include classic of EHS laminin (laminin 1) and nidogen (entactin). A large part of lamina densa is comprised by type IV collagen, which assembles into lattice network and anchored to the dermis via anchoring fibrils in the sublamina densa region in dermis.44 Anchoring fibrils consist of laterally associ ated dimers of type VII collagen. 45,46 Type VII collagen contains a small non-collagenous domain (NC2) at its C-terminal domain, that forms antiparallel dimer forma tion. The N-terminal domain of type VII collagen con tains a large 145 kd NC1 domain that binds type IV collagen in lamina densa or anchoring plaques. In this manner, anchoring fibrils exist as series of looping struc tures and bind to interstitial collagen fibers. If any of these components consisting the adhesive unit are lack ing, the adhesion at the dermo-epidermal junction would severely be interfered. The Diseases with Antibodies against the Keratinocyte Cell Surface The most common diseases with anti-keratinocyte cell

5 Keio J Med 1995, 44 (4): surface antibodies are classic type of pemphigus, which is divided into two major subtypes; pemphigus vul garis (PV) and pemphigus foliaceus (PF).8,9 Both are characterized by loss of cohesion between epidermal keratinocytes (acantholysis) and by circulating IgG auto antibodies against the keratinocyte cell surface, which bind to keratinocytes in vivo.8,9 The autoantigens in pemphigus have been extensively investigated, and shown to be desmosomal glycoproteins Thus PF antigen is the 160 kd Dsg1. PV sera react with a 130 kd Dsg3. Although there is a clear difference of reactivity be tween PV and PF sera, several immunoprecipitation or immunoblot studies 48,49 have shown that the sera of one third to half of PV patients react with both Dsg1 and Dsg3. The mechanism of this apparent cross-reactivity is at present unclear. It should be interesting to note that autoantibodies against these desmosomal cadherins are really patho genic, because, if IgG fraction purified from patients' sera injected into neonatal mice, the blisters mimicking patient's skin lesions can be induced in the mice.54 Using this animal model, Amagai et al have recently shown that antibodies against conformational epitopes on the pem phigus antigens are important in the pathogenesis. 55,56 They elaborated recombinant proteins of PV and PF antigens with proper conformation using baculovirus expression system, and showed that pathogenic anti bodies in patient sera can be completely absorbed with these recombinant proteins. More importantly, this result also indicates that affinity-column using these recombi nant proteins may be used for antigen-specific plasma pheresis as an ideal therapy for pemphigus in the future. Furthermore, this treatment may be a paradigm for many other types of autoimmune diseases, and should also be used for the therapy of those diseases. A new disease entity, paraneoplastic pemphigus (PNP), has recently been identified Anhalt et al proposed five criteria to define PNP57; painful mucosal erosions and polymorphous skin eruptions; the presence of neoplasia; acantholysis, keratinocyte necrosis and vacuolar-interface dermatitis in histology; intercellular deposition of IgG and complement and granular BMZ deposition of complement; and circulating antibodies which bind the cell surface of epidermis and other non stratifying epithelia and immunoprecipitate a complex of four proteins (250, 230, 210 and 190 kd). It is suggested that the 250 kd and the 210 kd proteins are desmoplakins (DP) I and II, major desmosomal plaque proteins, and the 230 kd protein is the 230 kd BP antigen, but the identity of the 190 kd protein has not yet been estab lished. More recently, another protein with molecular mass of 170 kd has been identified as a new candidate of PNP antigen.61 This protein was revealed to be a trans membrane protein, suggesting that it may play an import ant role in the pathogenesis of PNP. We have recently reported that the 130 kd PV antigen may also be involved in the pathogenesis in PNP.60 However, pathogenic anti bodies in PNP have not yet been identified. Besides these diseases with IgG class anti-cell surface antibodies, a number of cases showing IgA anti-cell surface antibodies have recently been reported More than 30 cases have been reported in the world literature to date with several different diagnoses, and we proposed the term intercellular IgA vesiculo-pustular dermatosis (IAVPD) for this group of patients.66 IAVPD is, like PV and PF, divided into two types from histo logical and immunopathological standpoints. One type shows clinically subcorneal pustular dermatosis (SPD) like features, showing pustules and IgA deposition in the upper epidermis, and is designated SPD type. The other type, intraepidermal neutrophilic dermatosis (IEN) type, is characterized by atypical vesiculopustular lesions, and shows pustule and IgA deposition in the entire epidermis. Similarly, circulating IgA autoantibodies react with cell surfaces of the keratinocytes in either the upper or entire epidermis, respectively. We have examined autoantigens for IAVPD with immunoblotting of desmosome enriched fraction obtained from bovine snout epidermis, and found that some IAVPD sera reacted with desmocollin, another desmosomal cadherin.66 However, more studies are necessary for identification of the target antigen(s) in this group of patients. The Diseases with Antibodies Against the Epidermal BMZ Bullous pemphigoid (BP) is the most common bullous disease with IgG anti-bmz antibodies and occur mainly in elder population. BP is characterized clinically by large tense blisters, and histologically by subepidermal bullae with infiltration of eosinophils. In vivo bound and circulating anti-bmz antibodies detected with immuno fluorescence assay are now a hallmark for the diagnosis of BP.8,9 Anti-BMZ antibodies in BP sera react with the BP230 and the BP ,35-39 The cdna for the BP230 was first isolated,30-32 and the studies for the cdna revealed that the BP230 is a cytoplasmic protein with similar structure to desmoplakin. Because autoantibodies can not access to such an intracellular molecule, the role of the anti-bp230 antibodies in the pathogenesis of BP is currently unknown. Subsequently, cdna for the BP180 was isolated, and this antigen has been shown to be a transmembrane protein of type two orientation and to consist of multiple collagen-like domains in its extra cellular region Recent studies using recombinant proteins have indicated that autoantibodies in BP sera recognize an epitope in the extracellular NC16a domain of the BP As mentioned above, pemphigus lesion can be pro

6 120 Hashimoto T: Autoimmune Blistering Skin Disrascs duced in neonatal mice by passive transfer of IgG purified from patient sera. However, BP skin lesion could not be induced by the same method. Recently, sequence comparison of BP180 cdnas has revealed that the homology around the pathogenic epitope in NC16a domain of the BP180 between human and mouse is very low, and the failure of blister induction in neonatal mice by injection of human IgG is considered to be due to inability of the human IgG to bind to the mouse BP180. Therefore, Liu et al produced rabbit antibodies by immunizing rabbit with mouse-specific peptide, and showed that the resultant rabbit antibodies could induce blister formation.38 This result strongly suggested the crucial role of anti-bp180 antibodies in the blister for mation in BP. Moreover, this study suggests that the affinity-column using this peptide containing the patho genic epitopes may be used as antigen-specific plasma pheresis, as is suggested in the treatment of pemphigus. Herpes gestationis (HG) is a rare autoimmune bullous disease of pregnancy and postpartum period,67 which occurs in less than 1:50,000 pregnancies67 and is clinically and immunologically reminiscent to BP. HG is charac terized immunopathologically by in vivo bound C3 and IgG at the basement membrane zone (BMZ) and by circulating HG factor,68 which was later shown to be complement-fixing IgG anti-bmz antibodies.69 These antibodies are reactive preferentially with the BP HG sera also recognize a common epitope in the extra cellular NC16a domain of the BP180.37,39 Cicatricial pemphigoid (CP) is characterized by almost exclusive involvement of the oral, ocular and other mucous membranes leaving scar formation. Although CP shows distinct lesions, it is occasionally difficult to be distinguished from BP. Titers of the circulating antibodies in CP are in general very low, and difficult to be detected in some cases. Several immunoprecipitation and immuno blot studies have identified two major BP antigens; the BP230 and the BP Another study has suggested that BP180 is the major target antigen for IgG or IgA antibodies in a group of this disease.72 Inpatients showing exclusively ocular lesions, IgA antibodies have been suggested to react specifically with a 45 kd protein, the nature of which has not been unraveled.73 In addition, a new group of CP has recently been identified, who showed IgG autoantibodies against epiligrin and is thus designated anti-epiligrin CP.74 Ultrastructurally, the anti gens targeted by IgG anti-bmz antibodies in patients with this disease have been localized to the lower lamina lucida. Because passive transfer of the high titer of anti epiligrin rabbit antibodies can induce blister formation in the newborn mice, the autoantibodies in the patients' sera are also considered to play an important role in the pathogenesis. However, the antigen molecules for CP are still controversial and considered to be heterogeneous. Epidermolysis bullosa acquisita (EBA) showed blisters and erosions after minor trauma, and these lesions leave extensive scar and milia formation. Like BP, EBA also showed in vivo bound and circulating IgG anti-bmz autoantibodies. However, EBA can be easily dis tinguished with immunofluorescence of 1.0 M NaCl split normal human skin section which is separated at the level of lamina lucida.75 Immunoelectron microscopic studies showed that EBA antibodies reacted with anchor ing fibrils.76 Both immunoblotting of human dermal extract and immunoprecipitation of radiolabeled cultured keratinocytes showed that the EBA antibodies react with type VII collagen, the major component of anchor ing fibrils.77 Linear IgA bullous dermatosis (LABD) is character ized by both in vivo bound and circulating IgA anti-bmz autoantibodies. Immunofluorescence of 1.0 M NaCl split skin section revealed that LABD is divided into two subgroups; lamina lucida type and sublamina densa type.78 Immunoelectron microscopic studies have also demonstrated that IgA is deposited in the lamina lucida adjacent to the plasma membrane of basal keratinocytes or in the sublamina densa region.79,81) However, antigen molecules for LABD have not been fully elucidated. Several studies have suggested that certain lamina lucida type LABD sera detected the 97 kd protein with immunoblotting of normal human epidermal extracts. 81,82 Either the 285 kd protein 83 or the 255 kd protein 12 was also reported to be detected by immunoblotting of human dermal extracts. In addition, type VII procollagen, the EBA antigen, has been reported to be detected by IgA anti-sublamina densa type LABD autoantibodies.84 These results indicate that LABD is a heterogeneous disease. Conclusion Recent biochemical and molecular biological studies have provided us important information on the auto antigens in various autoimmune blistering skin diseases, particularly, on the relationship between those auto antigens and constituent proteins in the desmosome and the hemidesmosome. Because cdnas coding for the antigens are available, these proteins can be clinically applied for; e.g. enzyme-linked immunosorbent assay for detection of the antibodies as the diagnostic method, and antigen-specific plasmapheresis or B-cell targeting with toxin-conjugated antigen as therapeutic methods. These studies on autoantigens in turn provide us bio logically important information to understand the mech anisms of adhesion in both the desmosome and the hemidesmosome. Acknowledgments: This work was supported in part by Grant-in-Aid for Scientific Research from the ministry of Education, Science and Culture of Japan ( ), a grant from the Ministry of Health and Welfare of Japan.

7 Keio J Med 1995, 44 (4): References 1. Moll R, Cowin P, Kapprell HP, Franke WW: Desmosomal proteins: new markers for identification and classification of tumors. Lab Invest 1986, 54: Schwarz MA, Owaribe K, Kartenbeck J, Franke WW: Desmo somcs and hemidesmosomes: constitutive molecular components. Annu Rev Cell Biol 1990, 6: Buxton RS, Cowin P, Franke WW, Garrod DR, Green KJ, King IA, Koch PJ, Magee Al, Rees DA, Stanley JR. Steinberg MS: Nomenclature of the desmosomal cadherins. J Cell Biol 1993, 121: Amagai M: Adhesion molecules. I: Keratinocyte-keratinocyte interactions; cadherins and pemphigus. J Invest Dermatol 1995, 104: Owaribe K, Nishizawa Y, Franke WW: Isolation and character ization of hemidesmosomes from bovine corneal cpithclial cells. Exp Cell Res 1991, 192: Owaribe K, Kartenbeck J, Stumpp S, Magin TM, Krieg T, Diaz LA, Franke WW: The hemidesmosomal plaque. I. Character ization of a major constituent protein as a differentiation marker for certain forms of epithelia. Differentiation 1990, 45: 21)7-221) 7. Yancey KB: Adhesion molecules. II: Interactions of keratinocytes with epidermal basement membrane. J Invest Dermatol 1995, 104: Stanley JR: Pemphigus and pemphigoid as paradigms of organ specific, autoantibody-mediated diseases. J Clin Invest 1989, 83: Stanley JR: Cell adhesion molecules as targets of autoantibodies in pemphigus and pemphigoid, bullous diseases due to defective epidermal cell adhesion. Adv IImunol 1993, 53: Koch PJ, Walsh MJ, Schmclz M, Goldschmidt MD, Zimbclmann R, Franke WW: Identification of dcsmoglein, a constitutive desmosomal glycoprotein, as a member of the cadherin family of cell adhesion molecules. Eur J Cell Biol 1990, 53: Nilles LA, Parry DAD, Powers EE, Angst BD, Wgner RM, Green KJ: Structural analysis and expression of human desmo glcin: a cadherin-like component of the dcsmosomc. J Cell Sci 1991, 99: Collins JE, Lcgan PK, Kenny TP, MacGarvie J, Holton JL. Garrod DR: Cloning and sequence analysis of desmosomal ghro proteins 2 and 3 (desmocollins): cadherin-like desmosomal ad hesion molecules with heterogeneous cytoplasmic domains. J Cell Biol 1991, 113: Lcgan PK, Yue KKM, Chidgey MAJ, Holton JL, Wilkinson RW, Garrod DR: The bovine desmocollin family: a new gene and expression patterns reflecting epithelial cell proliferation and differentiation. J Cell Biol 1994, 126: Virata MLA, Wagner RM, Parry DAD, Green KJ: Molecular structure of the human desmoplakin I and 11 amino terminus. Proc Natl Acad Sci USA 1992, 89: Stappenbeck TS, Bornslacger EA, Corcoran CM, Luu HH, Virata MLA, Green KJ: Functional analysis of desmoplakin domains: specification of the interaction with keratin versus vimentin intermediate filament networks. J Cell Biol 1993, 123: Cowin P, Kapprell HP, Franke WW, Tamkun J. Hynes RO: Plakoglobin: a protein common to different kinds of intercellular adhering junctions. Cell 1986: 46, Korman NJ, Eyrc RW, Kalus-Kovtun V, Stanley JR: Demon stration of an adhering-junction molecule (plakoglobin) in the autoantigens of pemphigus foliaceus and pemphigus vulgaris. N Engl J Mcd 1989, 321: Hatzfcld M, Kristjansson GI, Plessmann U, Weber K: Band 6 protein, a major constituent of desmosomes from stratified epi thclia, is a novel member of the armadillo multigene family. J Cell Sci 1994, 107: Tsukita SA, Tsukita SH: Desmocalmin: a calmodulin-binding high molecular weight protein isolated from desmosomes. J Cell Biol 1985, 101: Wiche G, Becker B, Luber K, Weitzer G, Castanon MJ, Hauptmann R, Stratowa C, Stewart M: Cloning and sequencing of rat plectin indicates a 466-kD polypeptidc chain with a three domain structure based on a central alpha-helical coiled coil. J Cell Biol 1991, 114: Skalli 0, Jones JCR, Gagescu R, Goldman RD: IFAP 300 is common to desmosomes and hemidesmosomes and is a possible linker of intermediate filaments to these junctions. J Cell Biol 1994, 125: Hieda Y, Tsukita SA, Tsukita SH: A new high molecular mass protein showing unique localization in desmosomal plaque. J Cell Biol 1989, 109: Hashimoto T, Amagai M, Parry DAD, Dixon TW, Tsukita SA, Tsukita SH, Miki K, Sakai K, Inokuchi Y, Kudoh J, Shimizu N, Nishikawa T: Dcsmoyokin, a 680kDa kcratinocytc plasma membrane-associated protein, is homologous to the protein encoded by human gene AHNAK. J Cell Sci 1993, 105: Pcifcr M, Wieschaus E: The segment polarity gene armadillo encodes a functionally modular protein that is the Drosophila homolog of human plakoglobin. Cell 1990, 63: Moll R, Franke WW, Schiller DL, Geiger B, Krepler R: The catalog of human cytokeratins: patterns of expression in normal epithelia, tumors and cultured cells. Cell 1982, 31: Coulombe PA, Hutton ME, Letai A, Hebert A, Paller AS, Fuchs E: Point mutations in human keratin 14 genes of epidermolysis bullosa simplex patients: genetic and functional analysis. Cell 1991, 66: Stanley JR, Hawley-Nelson P, Yuspa SH, Shevach EM, Katz SI: Characterization of bullous pemphigoid antigen: a unique base ment membrane protein of stratified squamous epithelia. Cell 1981, 24: Labib RS. Anhalt GJ, Patel HP, Mutasim DF, Diaz LA: Mol ecular heterogeneity of the bullous pemphigoid antigens as de tected by immunoblotting. J Immunol 1986, 136: Sugi T, Hashimoto T, Hibi T. Nishikawa T: Production of human monoclonal anti-basement membrane zone (BMZ) antibodies from a patient with bullous pemphigoid (BP) by Epstcin-Barr virus transformation. Analyses of the heterogeneity of anti-bmz antibodies in BP sera using them. J Clin Invest 1989, 84: Tanaka T, Parry DAD, Klaus-Kovtun V, Steinert PM, Stanley JR: Comparison of molecularly cloned bullous pemphigoid anti gen to dcsmoplakin I confirms that they define a new family of cell adhesion junction plaque proteins. J Biol Chem 1991, 266: Sawamura D, Li K, Chu ML, Uitto J: Human bullous pemphigoid antigen (BPAGI). Amino acid sequences deduced from cloned cdnas predict biologically important peptide segments and protein domains. J Biol Chem 1991,2_66: Amagai M, Hashimoto T, Tajima S, Inokuchi Y, Shimizu N, Saito M, Miki K, Nishikawa T: Partial edna cloning of the 230 kd mouse bullous pcmphigoid antigen by use of a human mono clonal anti-basement membrane zone antibody. J Invest Dcrmatol 1990, 95: Tamai K, Li K, Silos S, Rudnicka L, Hashimoto T. Nishikawa T, Uitto J: Interferon-g-mediated inactivation of transcription of the 230-kDa bullous pemphigoid antigen gene (BPAG1) provides novel insight into keratinocvte differentiation. J Biol Chem 1995, 270: Hieda Y, Nishizawa Y, Ucmatsu J. Owaribe K: Identification of a new hemidesmosomal protein, HD1: a major, high molecular

8 122 Hashimoto T: Autoimmune Blistering Skin Di,,cases mass component of isolated hemidesmosomes. J Cell Biol 1992, 116: Diaz LA, Ratrie H III, Saunders WS, Futamura S, Squiquera HL, Anhalt GJ, Giudice GJ: Isolation of a human epidermal cdna corresponding to the 180-kD autoantigen recognized by bullous pemphigoid and herpes gestationis sera. Immunolocal ization of this protein to the hemidesmosome. J Clin Invest 1990, 86: Giudicc GJ, Emcrgy DJ, Diaz LA: Cloning and primary structural analysis of the bullous pemphigoid autoantigen BP180. J Invest Dermatol 1992, 99: Giudice GJ, Emery DJ, Zelickson BD, Anhalt GJ, Liu Z, Diaz LA: Bullous pemphigoid and herpes gestationis autoantibodies recognize a common non-collagenous site on the BP180 ecto domain. J Immunol 1993, 151: Liu Z, Diaz LA, Troy JL, Taylor AF, Emery DJ, Fairley JA, Giudice GJ: A passive transfer model of the organ-specific auto immune disease, bullous pemphigoid, using antibodies generated against the hcmidesmosomal antigen, BP180. J Clin Invest 1993, 92: Hashimoto T, Matsumura K, Kawahara Y, Ohata Y, Nishikawa T: Immunoblot analysis using recombinant protein of the l80kd bullous pemphigoid antigen NC16a domain as an aid to the diagnosis of atypical subepidermal autoimmune bullous skin dis eases. Keio J Med 1995, 44: Sonnenberg A, Calafat J, Janssen H, Daams H, Helmer LM. Falcioni R, Kennel SJ, Aplin JD, Baker J, Loizidou M, Garrod D: Integrin ƒ 6/ƒÀ4 complex is located in hemidesmosomes, suggest ing a major role in epidermal cell-basement membrane adhesion. J Cell Biol 1991, 113: Rousselle P, Lunstrum GP, Kenne DR, Burgeson RE: Kalinin: an epithelium-specific basement membrane adhesion molecule that is a component of anchoring filaments. J Cell Biol 1991, 114: Carter WG, Ryan MC, Gahr PJ: Epiligrin, a new cell adhesion ligand for integrin ƒ 3ƒÀ1 in epithelial basement membranes. Cell 1991, 65: Marinkovich MP, Lunstrum GP, Kenne DR, Burgeson RE: The dermal-epidermal junction of human skin contains a novel laminin variant. J Cell Biol 1992, 119: Vandenberg P, Kern A, Ries A, Luckenbill-Edds L, Mann K, Kuhn K: Characterization of a type IV collagen major cell binding site with affinity to the ƒ 1ƒÀ1 and the ƒ 2ƒÀ1 integrins. J Cell Biol 1991, 113: Sakai LY, Kcene DR, Morris NP, Burgeson RE: Type VII collagen is a major structural component of anchoring fibrils. J Cell Biol 1986, 103: Ryynanen M, Ryynanen J, Sollberg S, lozzo RV, Knowlton RG, Uitto J: Genetic linkage of type VII collagen (COL7A1) to dominant dystrophic epidcrmolysis bullosa in families with ab normal anchoring fibrils. J Clin Invest 1992, 89: Stanley JR, Yaar M, Hawley-Nelson P, Katz SL Pemphigus antibodies identify a cell surface glycoprotein synthesized by human and mouse keratinocytcs. J Clin Invest 1982, 70: Eyre RW, Stanley JR: Identification of pemphigus vulgaris antigen extracted from normal human epidermis and comparison with pemphigus foliaceus antigen. J Clin Invest 1988, 81: Hashimoto T, Ogawa MM, Konohana A. Nishikawa T: Detection of pemphigus vulgaris and pemphigus foliaceus antigens by immunoblot analysis using different antigen sources. J Invest Dermatol 1990, 94: Amagai M, Klaus-Kovtun V, Stanley JR: Autoantibodies against a novel epithelial cadherin in pemphigus vulgaris, a disease of cell adhesion. Cell 1991, 67: Amagai M, Karpati S, Prussick R, Klaus-Kovtun V, Stanley JR: Autoantibodics against the amino-terminal cadherin-like binding domain of pemphigus vulgaris antigen are pathogenic. J Clin Invest 1992, 90: Dmochowski M, Hashimoto T, Garrod DR, Nishikawa T: Desmocollins I and II arc recognized by certain sera from patients with various types of pemphigus, particularly Brazilian pemphigus foliaceus. J Invest Dcrmatol 1993, 100: Vilela MJ, Hashimoto T, Nishikawa T, North AJ, Garrod DR: A simple epithelial cell line (MDCK) shows heterogeneity of desmoglein isoforms, one resembling pemphigus vulgaris antigen. J Cell Sci 1995, 108: Anhalt GJ, Labib RS, Voorhees JJ, Beals TF, Diaz LA: Induction of pemphigus in neonatal mice by passive transfer of IgG from patients with the disease. N Engl J Med 1982, 306: Amagai M, Hashimoto T, Shimizu N, Nishikawa T: Absorption of pathogenic autoantibodies by the extracellular domain of pem phigus vulgaris antigen (Dsg3) produced by baculovirus. J Clin Invest 1994, 94: Amagai M, Hashimoto T, Green KJ, Shimizu N, Nishikawa T: Antigen-specific immunoadsorption of pathogenic autoantibodies in pemphigus foliaccus. J Invest Dermatol 1995, 104: Anhalt GJ, Kim SC, Stanley JR, Korman NJ, Jabs DA. Kory M, Izumi H, Ratrie H III, Mutasim D, Ariss-Abdo L, Labib RS: Parancoplastic pemphigus. An autoimmune mucocutaneous disease associated with neoplasia. N Engl J Med 1990, 323: Oursler JR, Labib RS, Ariss-Abdo L, Burke T, O'Keefe EJ, Anhalt GJ: Human autoantibodies against desmoplakins in para neoplastic pemphigus. J Clin Invest 1992, 89: Nishibori Y, Hashimoto T, Ishiko A, Shimizu H, Korman NJ, Nishikawa T: Paraneoplastic pemphigus: the first case report from Japan. Dermatology 1995, 191: Hashimoto T, Amagai M, Watanabe K, Chorzelski TP, Bhogal BS, Black MM, Stevens HP, Boorsma DM, Korman NJ, Gamou S, Shimizu N, Nishikawa T: Characterization of paraneoplastic pemphigus autoantigens by immunoblot analysis. J Invest Dermatol 1995, 104: Anhalt GJ, Hilu J, Takehara K, Lee A, Casciola-Rosen L: Identification of a putative transmembrane autoantigen in para neoplastic pemphigus. Clin Res 1993, 41: 407A 62. Huff JC, Golitz LE, Kunke KS: Intraepidermal neutrophilic IgA dermatosis. N Engl J Med 1985, 313: Tagami H, Iwatsuki K, Iwase Y, Yamada M: Subcorneal pustular dermatosis with vesiculo-bullous eruption. Demonstration of sub corneal IgA deposits and a leukocyte chemotactic factor. Br J Dcrmatol 1983, 109: Hashimoto T. Inamoto N, Nakamura K, Nishikawa T: Inter cellular IgA dermatosis with clinical features of subcorncal pustu lar dermatosis. Arch Dermatol 1987: 123: Teraki Y, Amagai N, Hashimoto T, Kusunoki T, Nishikawa T: Intercellular IgA dermatosis of childhood. Selective deposition of monomer IgAl in the intercellular space of the epidermis. Arch Dcrmatol 1991, 127: Ebihara T, Hashimoto T, Iwatsuki K, Takigawa M, Ando M, Ohkawara A, Nishikawa T: Autoantigens for IgA anti-inter cellular antibodies of intercellular IgA vesiculopustular dermatosis. J Invest Dermatol 1991, 97: Shornick JK: Herpes gestationis. J Am Acad Dermatol 1987, 17: Jordon RE, Heine KG, Tappeiner G, Bushkell LL, Provost TT: The immunopathology of herpes gestationis. Immunofluorescence studies and characterization of 'HG factor'. J Clin Invest 1976, 57: Katz SI, Hertz KC, Yaoita H: Herpes gestationis. Immuno pathology and characterization of the HG factor. J Clin Invest 1976, 57: Morrison LH, Labib RS, Zone JJ, Diaz LA, Anhalt GJ: Herpes

9 Kcio J Med 1995, 44 (4): gestationis autoantibodies recognize a 180-kD human epidermal antigen. J Clin Invest 1988, 81: Bernard P, Prost C, Durepaire N, Basset Seguin N, Didierjean L, Saurat JH: The major cicatricial pemphigoid antigen is a 180-kD protein that shows immunologic cross-react i vi ties with the bullous pemphigoid antigen. J Invest Dermatol 1992, 99: Chan LS, Hammerberg C, Cooper KD: Cicatricial pemphigoid. Identification of two distinct sets of epidermal antigens by IgA and IgG class circulating autoantibodies. Arch Dermatol 1990, 126: 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: Domloge-Hultsch N, Gammon WR, Briggaman RA, Gil SG, Carter WG, Yanccy KB: Epiligrin, the major human keratinocyte integrin ligand, is a target in both an acquired autoimmune and an inherited subepidcrmal blistering skin disease. J Clin Invest 1992, 90: Gammon WR, Briggaman RA, Inman AO, Queen LL, Wheeler CE: Differentiating anti-lamina lucida and anti-sublamina densa anti-bmz antibodies by indirect immunofluorescence on 1.0M sodium chloride-separated skin. J Invest Dermatol 1984, 82: Shimizu H, McDonald JN, Gunner DB, Black MM. Bhogal B, Leigh IM, Whitehead PC, Eady RA: Epidermolysis bullosa acquisita antigen and the carboxy terminus of type VII collagen have a common immunolocalization to anchoring fibrils and lamina densa of basement membrane. Br J Dermatol 1990, 122: Woodley DT, Briggaman RA, O'Keefe EJ, Inman AO, Queen LL, Gammon WR: Identification of the skin basement-membrane autoantigen in epidermolysis bullosa acquisita. N Engl J Med 1984, 310: Willsteed E, Bhogal BS, Black MM, McKee P, Wojnarowska F: Use of I M NaCI split skin in the indirect immunofluorescence of the linear IgA bullous dermatoses. J Cutan Pathol 1990, 17: Yamasaki Y, Hashimoto T, Nishikawa T: Dermatitis herpeti formis with linear IgA deposition: ultrastructural localization of in vivo bound IgA. Acta Derm Vencreol 1982, 62: Onodcra Y, Hashimoto T, Miyakawa S, Shimizu H, Nishikawa T, Yamamoto K: A case of linear IgA bullous dermatosis of childhood: immunoelectron microscopic and IgA subclass studies. Dermatologica 1990, 180: Zone JJ, Taylor TB, Kadunce DP, Meyer U: Identification of the cutaneous basement membrane zone antigen and isolation of antibody in linear immunoglobulin A bullous dermatosis. J Clin Invest 1990, 85: Dmochowski M, Hashimoto T, Bhogal BS, Black MM, Zone JJ, Nishikawa T: Immunoblotting studies of linear IgA disease. J Dermatol Sci 1993, 6: Wojnarowska F, Whitehead P, Leigh IM, Bhogal BS, Black MM: Identification of the target antigen in chronic bullous disease of childhood and linear IgA disease of adults. Br J Dermatol 1991, 124: Rusenko KW, Gammon WR, Briggaman RA: Type VII collagen is the antigen recognized by IgA anti-sub lamina densa auto antibodies. J Invest Dermatol 1989, 92: 510