Severe alveolar bone resorption in Felty syndrome: a case report.

BACKGROUND: Felty syndrome is defined by three conditions: neutropenia, rheumatoid arthritis, and splenomegaly. Neutropenia associated with pancytopenia may further affect the dental condition of a patient. Periodontal treatment and surgery in patients with Felty syndrome necessitates cooperation with a hematologist. Here we present a case of a patient with Felty syndrome who was initially referred to the oral surgery hospital attached to the School of Dentistry for extensive periodontitis. She was effectively treated in collaboration with the hematology department. CASE PRESENTATION: A 55-year-old Asian woman visited our department with concerns of worsening tooth mobility, discomfort, and spontaneous gingival bleeding. Initial periodontal examination revealed generalized severe periodontitis (Stage IV Grade C) resulting from leukopenia/neutropenia and poor oral hygiene. A thorough treatment strategy involving comprehensive dental procedures, such as multiple extractions and extensive prosthetic treatment, was implemented. Following the diagnosis of Felty syndrome, the patient was started on treatment with oral prednisolone 40 mg/day, which effectively controlled the disease. Furthermore, there was no recurrence of severe periodontitis after the periodontal treatment. CONCLUSIONS: Dentists and physicians should be aware that immunocompromised individuals with pancytopenia and poor oral hygiene are at risk of developing extensive periodontitis. If their susceptibility to infection and pancytopenia-related bleeding can be managed, such patients can still receive comprehensive dental treatment, including teeth extractions and periodontal therapy. Cooperation among the dentist, hematologist, and patient is necessary to improve treatment outcomes and the patient's quality of life.

Prospective feasibility study of indigo naturalis ointment for chemotherapy-induced oral mucositis.

OBJECTIVES: Indigo naturalis, a herbal medicine effective against ulcerative colitis, exhibits anti-inflammatory effects and induces interleukin-22-mediated antimicrobial peptide production. Anti-inflammatory activity and the prevention of secondary infection are essential for the management of chemotherapy-induced oral mucositis (CIOM); therefore, we developed an indigo naturalis ointment to be administered topically for CIOM and evaluated its feasibility. METHODS: We performed a single-centre, open-label, prospective feasibility study from March 2017 to December 2018. The key eligibility criteria for the subjects were as follows: (1) receiving chemotherapy for a malignant tumour; (2) grade 1 or 2 CIOM and (3) receiving continuous oral care. The treatment protocol comprised topical indigo naturalis ointment application three times a day for 7 days. The primary endpoint assessed was feasibility. The secondary endpoints assessed were the changes in oral findings, oral cavity pain and safety. RESULTS: Nineteen patients with CIOM were enrolled. The average feasibility (the proportion of prescribed applications that were carried out) observed in this study was 94.7%±8.9% (95% CI 90.5% to 99.0%), which was higher than the expected feasibility. The revised oral assessment guide scores of the mucous membrane domain and total scores were significantly improved. All patients reported a reduction in oral cavity pain, with a median pain resolution duration of 6 days. No serious adverse events were observed. CONCLUSIONS: The indigo naturalis ointment was feasible, and showed the potential for efficacy and safety. Larger randomised controlled trials are needed to further assess the efficacy and safety of indigo naturalis compared with a placebo. TRIAL REGISTRATION NUMBER: UMIN000024271.

Management of generalized severe periodontitis using full-mouth disinfection and systemic antibiotics in a leukemic patient before stem cell transplantation: A case report.

The full-mouth disinfection protocol implemented in this case can be integrated into established protocols for treating severe periodontitis in the context of a hematological malignancy, without any interference with the cancer treatment.

Anti-centromere antibodies target centromere-kinetochore macrocomplex: a comprehensive autoantigen profiling.

OBJECTIVES: Anti-centromere antibodies (ACAs) are detected in patients with various autoimmune diseases such as Sjögren's syndrome (SS), systemic sclerosis (SSc) and primary biliary cholangitis (PBC). However, the targeted antigens of ACAs are not fully elucidated despite the accumulating understanding of the molecular structure of the centromere. The aim of this study was to comprehensively reveal the autoantigenicity of centromere proteins. METHODS: A centromere antigen library including 16 principal subcomplexes composed of 41 centromere proteins was constructed. Centromere protein/complex binding beads were used to detect serum ACAs in patients with SS, SSc and PBC. ACA-secreting cells in salivary glands obtained from patients with SS were detected with green fluorescent protein-fusion centromere antigens and semiquantified with confocal microscopy. RESULTS: A total of 241 individuals with SS, SSc or PBC and healthy controls were recruited for serum ACA profiling. A broad spectrum of serum autoantibodies was observed, and some of them had comparative frequency as anti-CENP-B antibody, which is the known major ACA. The prevalence of each antibody was shared across the three diseases. Immunostaining of SS salivary glands showed the accumulation of antibody-secreting cells (ASCs) specific for kinetochore, which is a part of the centromere, whereas little reactivity against CENP-B was seen. CONCLUSIONS: We demonstrated that serum autoantibodies target the centromere-kinetochore macrocomplex in patients with SS, SSc and PBC. The specificity of ASCs in SS salivary glands suggests kinetochore complex-driven autoantibody selection, providing insight into the underlying mechanism of ACA acquisition.

Value of labial salivary gland histopathology for diagnosis of Sjögren's syndrome in patients with anti-centromere antibody positivity.

AIM/INTRODUCTION: Although anti-centromere antibody (ACA)+ Sjögren's syndrome (SS) is considered a subtype of SS, it was not included in the recent American College of Rheumatology/ European League Against Rheumatism (ACR/EULAR) SS classification criteria. ACA+ patients without anti-SS-A/Ro antibodies require salivary gland histopathology to fulfill the ACR/EULAR criteria for diagnosis of SS. We reviewed salivary gland histology among ACA+ patients referred for the diagnosis of SS using the ACR/EULAR and Japanese criteria which does not require biopsy. METHOD: Data from 147 ACA+ patients with dry eyes and/or mouth who visited our department were retrospectively analyzed. Clinical, immunological, and histological data were collected and statistically analyzed. RESULT: Sixty-five patients (44%) had undergone labial salivary gland biopsy. The frequency of dry mouth was higher in ACA+ patients who had undergone labial salivary gland biopsy than in those who had not (P = .046), while there were no differences in biopsy rates between patients with and without sclerodactyly (P = .51). According to the current ACR/EULAR classification criteria, Greenspan grade of 3 or 4 for labial salivary gland histopathology is required in patients without anti-SS-A/Ro antibody for the diagnosis of SS. Four patients with Greenspan grades <3 and anti-SS-A/Ro antibody met the criteria for SS. In 54 patients in which the ACR/EULAR criteria were met, 53 patients were diagnosed with SS using the Japanese criteria. CONCLUSION: In ACA+/anti-SS-A/Ro- antibody patients, agreement between ACR/EULAR and Japanese criteria sets was excellent. For easily classifying ACA+ patients as SS cases, salivary gland biopsy should be performed in ACA+ patients with dry symptoms to identify ACA+ patients.

Antigen-driven selection of antibodies against SSA, SSB and the centromere 'complex', including a novel antigen, MIS12 complex, in human salivary glands.

OBJECTIVES: Recent evidences have revealed that anti-SSA/SSB antibodies, the major autoantibodies in Sjögren's syndrome (SS), are produced in salivary glands. This study aims to clarify overall of autoantibody production at lesion site, including anti-centromere antibody (ACA)-positive SS. METHODS: Antibodies of antibody-secreting cells in human salivary glands were produced as recombinant antibodies. The reactivity of these antibodies and their revertants were investigated by ELISA and newly developed antigen-binding beads assay, which can detect conformational epitopes. The target of uncharacterised antibodies was identified by immunoprecipitation and mass spectrometry. Autoantibody-secreting cells in salivary gland tissue were identified by immunohistochemistry using green fluorescent protein-autoantigen fusion proteins. RESULTS: A total of 256 lesion antibodies were generated, and 69 autoantibodies including 24 ACAs were identified among them. Beads assay could detect more autoantibodies than ELISA, suggesting autoantibodies target to antigens with native conformation. After somatic hypermutations were reverted, autoantibodies drastically decreased antigen reactivity. We showed that MIS12 complex, a novel target of ACA, and CENP-C are major targets of ACA produced in salivary glands by examining cloned antibodies and immunohistochemistry, whereas few anti-CENP-B antibodies were detected. The target profiling of serum ACA from 269 patients with SS, systemic sclerosis (SSc), primary biliary cirrhosis (PBC) and healthy controls revealed that ACA-positive patients have antibodies against various sites of centromere complex regardless of disease. CONCLUSION: We showed direct evidences of antigen-driven maturation of anti-SSA/SSB antibody and ACA in SS lesion. ACA recognises centromere 'complex' rather than individual protein, and this feature is common among patients with SS, SSc and PBC.

Treatment of severe generalized chronic periodontitis in a patient with Behçet's disease: A case report.

Behçet's disease is a systemic disorder of unknown etiology. It involves multiple organ systems and is characterized by recurring episodes of oral ulcers as well as ocular, genital, and skin lesions. Oral ulcers can affect tooth brushing and impair proper oral hygiene. As a result, a dental biofilm accumulates, and the condition of the teeth and periodontal tissue deteriorates. The aim of this case report is to highlight the efficacy of periodontal treatment for patients with Behçet's disease. A 51-year-old man with Behçet's disease presented with generalized severe periodontitis. After basic treatment of the periodontal tissues, periodontal surgery was performed at several sites with bony defects. However, the patient developed severe stomatitis in the oral mucosa and gingiva after periodontal surgery. Administration of the antimicrobial agent cefdinir had little effect on recovery; however, subsequent administration of sitafloxacin resulted in significant improvement of the stomatitis. This case demonstrates that periodontal therapy is very useful for alleviating the oral signs and symptoms of Behçet's disease. Systemic antibiotic treatment with sitafloxacin (but not cefdinir) and mechanical debridement were effective in preventing the recurrence of aphthous ulcer outbreaks after periodontal surgery.

Multiomic disease signatures converge to cytotoxic CD8 T cells in primary Sjögren's syndrome.

OBJECTIVES: Multiomics study was conducted to elucidate the crucial molecular mechanisms of primary Sjögren's syndrome (SS) pathology. METHODS: We generated multiple data set from well-defined patients with SS, which includes whole-blood transcriptomes, serum proteomes and peripheral immunophenotyping. Based on our newly generated data, we performed an extensive bioinformatic investigation. RESULTS: Our integrative analysis identified SS gene signatures (SGS) dysregulated in widespread omics layers, including epigenomes, mRNAs and proteins. SGS predominantly involved the interferon signature and ADAMs substrates. Besides, SGS was significantly overlapped with SS-causing genes indicated by a genome-wide association study and expression trait loci analyses. Combining the molecular signatures with immunophenotypic profiles revealed that cytotoxic CD8 -T cells- were associated with SGS. Further, we observed the activation of SGS in cytotoxic CD8 T cells isolated from patients with SS. CONCLUSIONS: Our multiomics investigation identified gene signatures deeply associated with SS pathology and showed the involvement of cytotoxic CD8 T cells. These integrative relations across multiple layers will facilitate our understanding of SS at the system level.

The onset risk of carcinoma in patients continuing tacrolimus topical treatment for oral lichen planus: a case report.

Oral lichen planus is a chronic inflammatory mucocutaneous disease. Topical use of steroids and other immuno-modulating therapies have been tried for this intractable condition. Nowadays, tacrolimus ointment is used more commonly as a choice for treatment. However, a number of discussions have taken place after tacrolimus was reported to be carcinogenic. This report describes a patient who applied tacrolimus ointment to the lower lip after being diagnosed with oral lichen planus in 2008, and whose lesion developed squamous cell carcinoma in 2010. Since the relationship between tacrolimus and cancer development has been reported in only a few cases, including this case report, the clinician must be careful selecting tacrolimus as a second-line treatment for oral lichen planus.

Characterization of Long-Term Cultured Murine Submandibular Gland Epithelial Cells.

PURPOSE: Human and rat salivary gland cell lines derived from tumors or genetic modification are currently available for research. Here, we attempted to culture and characterize long-term cultured cells spontaneously derived from wild type murine submandibular glands (SGs). METHODS: SGs were removed from 3-week-old C57B/6J female mice and dissociated by collagenase type 1 and hyaluronidase digestion. Isolated SG epithelial cells were cultured in low calcium, serum-free growth media in the presence of cholera toxin (CT) during early passages. Single-cell colonies were isolated by limiting dilution culture after 25 passages. Early- and late-stage cell cultures were characterized for keratin 14, keratin 18, α-smooth muscle actin, and p63 by immunostaining and quantitative real-time PCR analysis. RESULTS: SG epithelial cells cultured in optimized media maintained their proliferative ability and morphology for over 80 passages. Long-term cultured cells expressed keratin 14, keratin 18, and p63, indicative of an epithelial phenotype. CONCLUSIONS: Epithelial cells originating from wild type murine SGs could be cultured for longer periods of time and remain phenotypically similar to ductal basal epithelium.

Pathogenic relevance of IgG and IgM antibodies against desmoglein 3 in blister formation in pemphigus vulgaris.

Pemphigus vulgaris is an autoimmune disease caused by IgG antibodies against desmoglein 3 (Dsg3). Previously, we isolated a pathogenic mAb against Dsg3, AK23 IgG, which induces a pemphigus vulgaris-like phenotype characterized by blister formation. In the present study, we generated a transgenic mouse expressing AK23 IgM to examine B-cell tolerance and the pathogenic role of IgM. Autoreactive transgenic B cells were found in the spleen and lymph nodes, whereas anti-Dsg3 AK23 IgM was detected in the cardiovascular circulation. The transgenic mice did not develop an obvious pemphigus vulgaris phenotype, however, even though an excess of AK23 IgM was passively transferred to neonatal mice. Similarly, when hybridoma cells producing AK23 IgM were inoculated into adult mice, no blistering was observed. Immunoelectron microscopy revealed IgM binding at the edges of desmosomes or interdesmosomal cell membranes, but not in the desmosome core, where AK23 IgG binding has been frequently detected. Furthermore, in an in vitro dissociation assay using cultured keratinocytes, AK23 IgG and AK23 IgM F(ab')(2) fragments, but not AK23 IgM, induced fragmentation of epidermal sheets. Together, these observations indicate that antibodies must gain access to Dsg3 integrated within desmosomes to induce the loss of keratinocyte cell-cell adhesion. These findings provide an important framework for improved understanding of B-cell tolerance and the pathophysiology of blister formation in pemphigus.

Subcellular localization of desmosomal components is different between desmoglein3 knockout mice and pemphigus vulgaris model mice.

BACKGROUND: The desmoglein 3 (Dsg3) knockout mouse and pemphigus vulgaris (PV) mouse model present a similar type of supra-basal acantholysis, even though the subcellular mechanism is considered to be completely different. OBJECTIVES: To detect changes in the desmosomal molecular composition in Dsg3-/- mice and PV model mice to highlight the precise mechanism for acantholysis at an ultrastructural level. METHODS: Using epithelia from Dsg3-/- mice, PV model mice, and their respective control mice, the desmosomal components were immunostained using a post-embedding immunogold labeling method, and their precise localization and the labeling density were statistically analyzed in the desmosomes before the occurrence of acantholysis. RESULTS: Positive findings were detected in desmoplakin and plakoglobin. In the Dsg3-/- mice, the localization of desmoplakin shifted 12.6nm toward the cytoplasm and the plakoglobin labeling density per desmosome decreased 31% in the desmosomes. In the PV model mice Desmoplakin shifted 22.7nm more distantly from the plasma membrane but the labeling density per desmosome showed no significant difference, including plakoglobin. Similar results were obtained when analyzing the desmosomes of spinous cells in the mid-epidermis. CONCLUSION: These results showed the functional blocking of Dsg3 by autoantibody binding and the genetic defect of Dsg3 to induce different changes in the cytoplasmic desmosomal plaque proteins. A decrease in the level of plakoglobin is therefore not involved in the acantholysis in the PV model mice. The desmoplakin shift from the desmosomal plaque, which is induced by autoantibody binding under in vivo conditions in the PV model mouse, could be an early molecular change before the occurrence of acantholysis.

Efficacy of mouth rinse in preventing oral mucositis in patients receiving high-dose cytarabine for allogeneic hematopoietic stem cell transplantation.

High-dose cytarabine is one of the major components of the conditioning regimen for hematopoietic stem cell transplantation (HSCT), and frequently causes severe oral mucositis. We have recently demonstrated that cytarabine is excreted into the saliva in patients receiving high-dose cytarabine, and proposed that it might locally and directly contribute to the development of oral mucositis. Therefore, this study was performed to assess whether removing the excreted cytarabine in the saliva by intensive mouth rinse during high-dose cytarabine infusion could reduce the incidence of oral mucositis. Fifteen patients with hematologic malignancies undergoing allogeneic HSCT who received total body irradiation (12 Gy) and high-dose cytarabine at a dose of 3 g/m(2) every 12 h for 4 days as a conditioning were evaluated. Patients were instructed to rinse their mouths using ice-cold water every 10 min, starting simultaneously with the 2-h cytarabine infusion and continuing up to 1 h after completion of each infusion. Oral mucositis was graded on a daily basis according to the National Cancer Institute, Common Toxicity Criteria. Thirty-five patients who previously underwent the same conditioning without mouth rinse served as controls. The incidence of Grades 2-3 and Grade 3 oral mucositis was significantly reduced in patients who performed mouth rinse as compared with the controls (40 vs. 80%, P = 0.009; 0 vs. 25. 7%, P = 0.02). In conclusion, mouth rinse during and shortly after high-dose cytarabine infusion could be an effective and inexpensive measure in reducing the incidence of moderate to severe oral mucositis caused by high-dose cytarabine. This finding strongly suggests the role of cytarabine excretion in the saliva in the development of cytarabine-associated oral mucositis.

Autoreactive B-cell elimination by pathogenic IgG specific for the same antigen: implications for peripheral tolerance.

Harmful pathogenic IgG auto-antibodies are produced against desmoglein 3 (Dsg3) in pemphigus vulgaris, an autoimmune blistering disease. Dsg3 is a cadherin-type cell adhesion molecule expressed in desmosomes of the skin and mucous membranes. In AK7-transgenic mice expressing non-pathogenic AK7 IgM against Dsg3, autoreactive transgenic B cells escape from the deletion or inactivation and exist in the periphery. However, when a pathogenic anti-Dsg3 IgG1 mAb (AK23) capable of inducing blisters was injected into AK7-transgenic mice, AK7 B cells were eliminated from the bone marrow (BM) and spleen only when Dsg3 was expressed in the periphery. In contrast, non-pathogenic IgG mAbs (AK7, AK9) failed to eliminate AK7 B cells. Interestingly, the AK23-mediated elimination of mature AK7 B cells in the spleen was significantly diminished in AK7-transgenic mice on a Rag2(-/-) background while BM B cells were still eliminated, suggesting the presence of T-cell-dependent and -independent mechanisms. T cell transfer studies into AK7-Rag2(-/-) mice revealed that autoreactive B-cell elimination in the periphery requires CD4(+) T cells from wild-type mice but not from gld (FasL mutant) mice. The B-cell elimination was impaired in both BM and periphery when Bcl2 was over-expressed in AK7 B cells. These findings suggest that autoreactive B cells exist unless they are harmful, but once harmful or dangerous events such as tissue destruction are sensed, the mature autoreactive B cells in the periphery are eliminated via a Fas-mediated process in a CD4(+) T cell-dependent manner.

No activation of urokinase plasminogen activator by anti-desmoglein 3 monoclonal IgG antibodies in cultured human keratinocytes.

BACKGROUND: Although pemphigus vulgaris (PV)-IgG has been shown to activate urokinase plasminogen activator (uPA) in cultured keratinocytes, activation of uPA is thought to have no primary role in PV-acantholysis, because PV-IgG is still pathogenic in uPA- and tissue-PA-knockout mice. OBJECTIVE: To determine if PV-IgG-induced uPA activation is due to specific antibody against Dsg3, we examined whether or not pathogenic monoclonal anti-Dsg3 antibody can activate uPA, because PV-IgG is thought to contain antibodies against unknown antigens besides Dsg3. METHODS: We stimulated cultured normal human and DJM-1 keratinocytes with monoclonal anti-Dsg3 IgG1 antibodies (pathogenic AK23, AK19 and nonpathogenic AK18, AK20), negative control monoclonal mouse IgG1 and positive control PV-IgG. Cells were treated with IgGs over a time course of 24h, and uPA-protein content and activity in the culture medium were determined by enzyme-linked immunosorbent assay (ELISA) and chromogenic assay, respectively. RESULTS: The uPA-protein content in samples treated with or without pathogenic, nonpathogenic, control monoclonal mouse IgG1s and PV-IgGs increased continuously up to 24h, with no differences between samples, suggesting a spontaneous secretion. In contrast, uPA activity in the culture medium of cells treated with PV-IgG increased dramatically, whereas that of cells treated with all AK-IgGs and control monoclonal mouse IgG1 did not increase at all. CONCLUSION: These results suggest that PV-IgG-dependent uPA activation is not related to anti-Dsg3 antibody activity, which is an essential factor in PV-IgG acantholysis, and that it may be due to other antigens than Dsg3 or unknown factors contained in PV-IgG fraction.

Anti-desmoglein 3 (Dsg3) monoclonal antibodies deplete desmosomes of Dsg3 and differ in their Dsg3-depleting activities related to pathogenicity.

Pemphigus vulgaris (PV) is an autoimmune blistering disease, characterized by the loss of cell-cell adhesion between epidermal keratinocytes and the presence of autoantibody against desmoglein 3 (Dsg3), which provides adhesive integrity to desmosomes between adjacent keratinocytes. We have previously shown that PV-IgG purified from patients depletes desmosomes of Dsg3. However, PV-IgG contains not only antibodies against a variety of different epitopes of Dsg3 but also against other unknown antigens. Therefore, we examined whether the Dsg3-depleting activity of PV-IgG is generated specifically by anti-Dsg3 activity in a human squamous cell carcinoma cell line (DJM-1) and normal human keratinocytes by using four different pathogenic and nonpathogenic monoclonal antibodies against Dsg3. We demonstrate that these monoclonal antibodies deplete cells and desmosomes of Dsg3, as PV-IgG does. Individual monoclonal anti-Dsg3 antibodies display characteristic limits to their Dsg3-depleting activity, which correlates with their pathogenic activities. In combination, these antibodies exert a cumulative or synergistic effect, which may explain the potent Dsg3-depleting capability of PV-IgG, which is polyclonal. Finally, although Dsg3-depletion activity correlated with AK-monoclonal antibody pathogenicity in mouse models, the residual level of Dsg3, when below approximately 50%, does not correlate with the adhesive strength index in the present study. This may suggest that although the Dsg3 depletion is not indicative for adhesive strength, the level of Dsg3 can be used as a read-out of pathogenic changes within the cell and that the Dsg3 depletion from desmosomes plays an important role in skin fragility or susceptibility to blister formation in PV patients.

Pathogenic monoclonal antibody against desmoglein 3 augments desmoglein 3 and p38 MAPK phosphorylation in human squamous carcinoma cell line.

Pemphigus vulgaris is an autoimmune blistering disease characterized by cell-cell detachment of epidermal cells. Autoantibody against desmoglein (Dsg) 3, a transmembrane glycoprotein that mediates the association of desmosomes, plays a major role in blistering in pemphigus vulgaris (PV). The mechanisms of autoantibody-induced acantholysis have not been clarified. We previously reported that PV-IgG induces phosphorylation of Dsg3, decreases Dsg3 on the cell surface and forms Dsg3-depleted desmosomes in cultured keratinocytes, and that cell treatment with a potent pathogenic monoclonal antibody against Dsg3 (AK23 mAb) decreases the amount of Dsg3 in cultured keratinocytes. Although the precise mechanisms remain unclear, we have proposed the involvement of intracellular signal transduction resulting from the binding of autoantibodies to Dsg3. In this study, we examined whether AK23 mAb augments phosphorylation of Dsg3 and p38 mitogen-activating protein kinase (MAPK) in a human squamous cell line, DJM-1 cells. AK23 mAb increased serine phosphorylation of Dsg3 and augmented activation levels of p38 MAPK. These results indicate that antibodies bind to Dsg3, but not other antigens, in the IgG fraction and can induce activation of signal transduction.

Synergistic pathogenic effects of combined mouse monoclonal anti-desmoglein 3 IgG antibodies on pemphigus vulgaris blister formation.

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by anti-desmoglein 3 (Dsg3) IgG antibodies. Previously, we generated an active mouse model for PV by adoptive transfer of splenocytes from immunized or naive Dsg3(-/-) mice. In this study, we isolated 10 anti-Dsg3 IgG mAbs (NAK-series) from PV model mice generated by transfer of naive Dsg3(-/-) splenocytes. We characterized their epitopes using domain-swapped and point-mutated Dsg1/Dsg3 molecules and examined their pathogenic activities in blister formation in three different assays. In a passive transfer model using neonatal mice, eight of 10 NAK mAbs showed pathogenic activity when injected together with half the minimum pathogenic dose of anti-Dsg1 IgG autoantibodies from pemphigus foliaceus (PF) patients. None of the mAbs could induce the PV phenotype when individual hybridoma clones were inoculated by peritoneal injection into adult Rag2(-/-) mice. NAK mAbs displayed a range of potency in an in vitro dissociation assay using primary cultured mouse keratinocytes. Interestingly, when multiple hybridoma clones recognizing different epitopes were inoculated in combination, recipient mice developed the PV phenotype. In vitro dissociation assays confirmed that combined NAK mAbs had synergistic pathogenic effects. These findings indicate that although an individual anti-Dsg3 IgG is not sufficient to cause blistering in adult mice, several together can induce the PV phenotype. These mAbs will provide a valuable tool to investigate the molecular mechanisms of blister formation, mimicking the effects of the polyclonal IgG antibodies found in patients.

Tolerance induction by the blockade of CD40/CD154 interaction in pemphigus vulgaris mouse model.

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by IgG autoantibodies against desmoglein 3 (Dsg3). We have recently developed an active disease mouse model for PV by adoptive transfer of splenocytes from Dsg3(-/-) mice. The purpose of this study was to determine the role of CD40/CD154 interaction in the pathogenic antibody production and development of the disease in PV model mice. When anti-CD154 monoclonal antibody (mAb) was administered to recipient mice prior to adoptive transfer, anti-CD154 mAb almost completely blocked the anti-Dsg3 IgG production and prevented blister formation. The blockade of CD40/CD154 interaction induced tolerance against Dsg3 as the suppression of antibody production was observed through day 70, and it was maintained even after challenge by immunization with recombinant mouse Dsg3 or by adoptive transfer of immunized Dsg3(-/-) splenocytes. Furthermore, the tolerance to Dsg3 was transferable because cotransfer of splenocytes from anti-CD154 mAb-treated mice and naïve Dsg3(-/-) splenocytes significantly suppressed anti-Dsg3 IgG production in recipient mice. In contrast, when anti-CD154 mAb was injected after the mice had developed the PV phenotype, no significant suppression of the production of anti-Dsg3 IgG was observed. These findings indicate that the CD40/CD154 interaction is essential for the induction of pathogenic anti-Dsg3 IgG antibodies and that antigen-specific immune-regulatory cells induced by anti-CD154 mAb would hold a therapeutic option for autoimmune diseases.