Epidermal polymeric immunoglobulin receptors: leads from intraepidermal neutrophilic IgA dermatosis-type IgA pemphigus.

In this study, we attempted to identify unknown autoantigen for intraepidermal neutrophilic IgA dermatosis-type IgA pemphigus by novel IgA-specific immunoprecipitation. Mass-spectrometry study identified polymeric immunoglobulin receptor (PIGR) as the candidate protein, and we confirmed that PIGR expressed in both epidermis and cultured keratinocytes. Eukaryotic recombinant protein of PIGR expressed in COS7 cells was reacted with both patient and normal sera, indicating that PIGR binds physiologically to IgA. To detect antigen-specific binding by IgA autoantibodies, we performed several experiments using deglycosylated PIGR and F(ab)2 fragments from patient sera. However, these analyses suggested that patient IgA bound physiologically, but not immunologically, to PIGR. Nevertheless, our study provided two important insights. Newly developed IgA-immunoprecipitation system should be a useful tool in the future study of identification of antigens for IgA autoantibodies. Detection of epidermal PIGR in this study confirmed previous results and indicated possible immunological role of PIGR in epidermis.

Anti-NXP2 autoantibodies in adult patients with idiopathic inflammatory myopathies: possible association with malignancy.

OBJECTIVES: Myositis-specific autoantibodies (MSAs) are useful tools for identifying clinically homogeneous subsets and predicting prognosis of patients with idiopathic inflammatory myopathies (IIM) including polymyositis (PM) and dermatomyositis (DM). Recent studies have shown that anti-NXP2 antibody (Ab) is a major MSA in juvenile dermatomyositis (JDM). In this study the frequencies and clinical associations of anti-NXP2 Ab were evaluated in adult patients with IIM. METHODS: Clinical data and serum samples were collected from 507 adult Japanese patients with IIM (445 with DM and 62 with PM). Eleven patients with JDM, 108 with systemic lupus erythematosus, 433 with systemic sclerosis and 124 with idiopathic pulmonary fibrosis were assessed as disease controls. Serum was examined for anti-NXP2 Ab by immunoprecipitation and western blotting using polyclonal anti-NXP2 Ab. RESULTS: Seven patients (1.6%) with adult DM and one (1.6%) with adult PM were positive for anti-NXP2 Ab. Except for two patients with JDM, none of the disease controls were positive for this autoantibody. Among eight adult patients with IIM, three had internal malignancies within 3 years of diagnosis of IIM. Another patient with DM also had a metastatic cancer at the diagnosis. All of the carcinomas were at an advanced stage (stage IIIb-IV). CONCLUSIONS: While less common than in juvenile IIM, anti-NXP2 Ab was found in adult IIM. Anti-NXP2 Ab may be associated with adult IIM with malignancy.

Low-dose cyclosporin improves the health-related quality of life in Japanese psoriasis patients dissatisfied with topical corticosteroid monotherapy.

Psoriasis greatly impacts the health-related quality of life of patients, including any dermatological conditions that are listed in the dermatology life quality index (DLQI). We investigated the relationships between DLQI and the degree of patient satisfaction using questionnaires among psoriasis patients treated only with topical corticosteroids. Patients who were dissatisfied with topical corticosteroids alone and agreed to receive cyclosporin were given low-dose oral cyclosporin. We assessed changes of the DLQI and the psoriasis area and severity index (PASI) scores in patients dissatisfied with treatment during the period of cyclosporin addition. Of 32 enrolled patients, 17 reported dissatisfaction with the current treatment of topical corticosteroids alone. There was a significantly positive correlation between the degree of patient satisfaction questionnaires and the DLQI of these 32 patients. Among the 17 dissatisfied patients, 12 patients agreed to receive additional cyclosporin therapy and five did not. The 12 patients who started on cyclosporin had a significantly lower PASI after 12 weeks than they did at baseline. The DLQI improved significantly after 12 weeks in the cyclosporin-treated patients. The 12 patients who agreed to receive cyclosporin showed a significantly lower DLQI at 12 weeks compared to the five patients who declined the addition of cyclosporin to their treatment. Assessing the degree of patient satisfaction with therapy using a questionnaire could be useful for improving clinical interventions in psoriasis patients. Low-dose oral cyclosporin could be effective in patients who are dissatisfied with topical corticosteroid treatment alone.

Clinical and immunological profiles of anti-BP230-type bullous pemphigoid: Restriction of epitopes to the C-terminal domain of BP230, shown by novel ELISAs of BP230-domain specific recombinant proteins.

OBJECTIVES: To confirm that sera from some BP patients reactive exclusively to the BP230 and to study the clinical and immunological characteristics of this condition. MATERIALS AND METHODS: BP patients were divided into three groups: BP reactive only to BP230 (BP230-BP), BP reactive to both BP180 and BP230 (BP180-BP230-BP) and BP reactive only to BP180 (BP180-BP), based on the results of standard ELISAs for BP180 and BP230. Clinical features were statistically analyzed among the three groups. Then, targeted epitopes in each group were studied by immunoblotting and novel ELISAs using three domain-specific BP230 recombinant proteins. RESULTS: Forty-one, 65 and 47 of 153 BP patients were categorized as BP230-BP, BP180-BP230-BP and BP180-BP, respectively. Clinically, BP230-BP patients showed significantly lower severity, less need of systemic steroids and better responses to various treatments, suggesting that BP230-BP is a milder condition. Immunoblotting and ELISAs of domain-specific BP230 recombinant proteins indicated that, while BP180-BP230-BP sera reacted with all three domains of BP230, BP230-BP sera reacted more frequently with epitopes in the BP230 C-terminal domain. CONCLUSION: We propose a new disease entity, named anti-BP230-type BP, in which anti-BP230 antibodies might be pathogenic and react specifically with the BP230 C-terminal domain. While anti-BP230 antibodies in BP180-BP230-BP seem to be produced via intermolecular epitope spreading, anti-BP230 antibodies in BP230-BP are considered to be produced by different mechanisms.

Integrin ß4 is a major target antigen in pure ocular mucous membrane pemphigoid.

Previous studies of ocular mucous membrane pemphigoid (OMMP) have identified several components of the basement membrane zone to be autoantigens, including integrin ß4. However, there are no extensive or definitive reported studies that address this, particularly in pure OMMP. To clarify the major autoantigens in pure OMMP. In this study, we examined sera from 43 pure OMMP patients for both IgG and IgA antibodies using newly developed immunoblotting analyses with a hemidesmosome-rich fraction and various recombinant proteins of integrin α6ß4, in addition to our routine immune-serological tests. Using a hemidesmosome-rich fraction, sera from patients with pure OMMP demonstrated reactivity of IgG and/or IgA antibodies to integrin ß4, BP180 and laminin-332. The reactivity of pure OMMP sera to integrin ß4 was further confirmed by immunoblotting using integrin ß4 recombinant proteins. Using concentrated supernatant of HaCaT cells, only one serum sample showed positive IgG and IgA reactivity to LAD-1, the ectodomain of BP180. None of the pure OMMP sera reacted with any autoantigens on immunoblotting using normal human epidermal or dermal extracts, or purified human laminin-332. Integrin ß4 was considered to be the major and specific autoantigen for pure OMMP. The new methods established in this study are useful for detection of various autoantigens, particularly integrin ß4.

Epiplakin Is a Paraneoplastic Pemphigus Autoantigen and Related to Bronchiolitis Obliterans in Japanese Patients.

All plakin family proteins are known to be autoantigens in paraneoplastic pemphigus (PNP). In this study, we first examined whether PNP sera also react with epiplakin, another plakin protein, by various immunological methods using 48 Japanese PNP sera. Immunofluorescence confirmed that cultured keratinocytes expressed epiplakin. Epiplakin was detected by 72.9% of PNP sera by immunoprecipitation-immunoblotting with KU-8 cell extract, but not by immunoblotting of either normal human epidermal extract or KU-8 cell extract. Epiplakin was essentially not detected by 95 disease and normal control sera. Statistical analyses of various clinical and immunological findings revealed a significant correlation of the presence of anti-epiplakin antibodies with both bronchiolitis obliterans and mortality. No epiplakin-negative PNP case developed bronchiolitis obliterans. However, although 29.4% of European patients with PNP had bronchiolitis obliterans, significant correlation with anti-epiplakin autoantibodies was not observed. In further studies for lung, immunofluorescence showed the presence of epiplakin in normal human lung, particularly respiratory bronchiole, immunoprecipitation-immunoblotting showed that PNP sera reacted with epiplakin in cultured lung cells, and mice injected with polyclonal antibody specific to epiplakin histopathologically showed abnormal changes in small airway epithelia. These results indicated that epiplakin is one of the major PNP autoantigens and is related to PNP-related bronchiolitis obliterans.

Linear IgA/IgG bullous dermatosis reacts with multiple laminins and integrins.

BACKGROUND: Since the original description by Zone et al in 1994, the disease entity and target antigens in linear IgA/IgG bullous dermatosis (LAGBD) have not been clarified in 20 years. OBJECTIVES: To determine autoantibodies and autoantigens in a new LAGBD case which showed atypical clinical and histopathological findings without apparent mucosal involvement. MATERIALS AND METHODS: We performed various indirect immunofluorescence and immunoblotting studies. RESULTS: Indirect immunofluorescence of 1M NaCl-split skin showed IgG and IgA reactivity with both epidermal and dermal sides. Immunoblotting studies using various antigen sources revealed circulating IgG and IgA antibodies reactive with laminin-332, laminin-γ1 and integrin α6ß4 in various patterns. Absorption study using recombinant proteins of laminin-γ1 indicated that the patient serum reacted with different epitopes between laminin-γ1 and laminin-γ2. CONCLUSIONS: This study presented for the first time a LAGBD patient with IgG and IgA antibodies to various laminins and integrins.

Anti-α-2-macroglobulin-like-1 autoantibodies are detected frequently and may be pathogenic in paraneoplastic pemphigus.

Paraneoplastic pemphigus (PNP) shows autoantibodies mainly to plakin and desmosomal cadherin family proteins. We have recently identified alpha-2-macroglobulin-like-1 (A2ML1), a broad range protease inhibitor, as a unique PNP antigen. In this study, we tested a large number of PNP sera by various methods. Forty (69.0%) of 58 PNP sera recognized A2ML1 recombinant protein expressed in COS7 cells by immunofluorescence (IF) and/or immunoprecipitation (IP)/immunoblotting (IB). IP/IB showed higher sensitivity than IF. In addition, 22 (37.9%) PNP sera reacted with A2ML1 by IB of cultured normal human keratinocytes (NHKs) under non-reducing conditions. Statistical analyses using various clinical and immunological data showed that the presence of anti-A2ML1 autoantibodies was associated with early disease onset and absence of ocular lesions. Next, to investigate the pathogenic role of anti-A2ML1 antibody, we performed additional functional studies. Addition of anti-A2ML1 polyclonal antibody to culture media decreased NHK cell adhesion examined by dissociation assay, and increased plasmin activity detected by casein zymography, suggesting that anti-A2ML1 antibody may decrease NHK cell adhesion through plasmin activation by inhibition of A2ML1. This study demonstrates that autoantibodies to A2ML1 are frequently and specifically detected and may have a pathogenic role in PNP.

Interaction of plectin and intermediate filaments.

BACKGROUND: Plectin, a member of the plakin family proteins, is a high molecular weight protein that is ubiquitously expressed. It acts as a cytolinker for the three major components of the cyotoskeleton, namely actin microfilaments, microtubules and intermediate filaments. OBJECTIVE: The aim of our experiments was to identify new binding sites for intermediate filaments on plectin and to specify these sites. METHODS: We introduced truncated forms of plectin into several cell lines and observe interaction between plectin and intermediate filaments. RESULTS: We found that a linker region in the COOH-terminal end of plectin was required for the association of the protein with intermediate filaments. In addition, we also demonstrated that a serine residue at position 4645 of plectin may have a role on binding of plectin to intermediate filaments. CONCLUSION: A linker region in the COOH-terminal end and serine residue at position 4645 may be important for the binding of plectin to intermediate filaments.

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).