anti-Dsg3 Antibodies Research Articles

Detection of antibodies against the non-calcium-dependent epitopes of desmoglein 3 in pemphigus vulgaris and their pathogenic significance

Antidesmoglein (anti-Dsg) 3 serum antibody titres are usually correlated with the disease activity of pemphigus vulgaris (PV), but some patients retain high titres even in remission. The aim of our study was to determine whether anti-Dsg3 antibodies in PV sera recognized calcium (Ca(2+) )-dependent or non-Ca(2+) -dependent epitopes, and to evaluate their pathogenicity. Dsg3 baculoprotein-coated enzyme-linked immunosorbent assay (ELISA) plates were treated with 0.5 mmol L(-1) ethylenediaminetetraacetic acid (EDTA). The binding ability of anti-Dsg3 monoclonal antibodies (mAbs) was analysed. Eight of the 83 patients with PV who were screened had elevated Dsg3 ELISA index values > 00 in remission. The binding ability of these PV sera was analysed. We evaluated the pathogenicity of anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes using a dissociation assay. The reactivity of pathogenic anti-Dsg3 mAbs against the Ca(2+) -dependent epitopes diminished markedly in the EDTA-treated ELISA, whereas no such reduction was observed in mAbs against the non-Ca(2+) -dependent epitopes. The sera of all the patients contained antibodies against both Ca(2+) -dependent and non-Ca(2+) -dependent epitopes. In six out of the eight patients, the ratio of antibodies against Ca(2+) -dependent to non-Ca(2+) -dependent epitopes decreased in remission. EDTA-treated Dsg3 baculoproteins adsorbed anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes, but the remnant PV antibodies retained the ability to induce acantholysis in the dissociation assay. We have established an assay to measure indirectly the titres of anti-Dsg3 serum antibodies against the Ca(2+) -dependent epitopes, based on the differences between EDTA-untreated and EDTA-treated ELISA index values, as a routine laboratory test to reflect the pathogenic anti-Dsg3 serum antibody titres more accurately.

Autoantibody detection in bullous pemphigoid: Clinical evaluation of the EUROPLUS™ Dermatology Mosaic

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Autoantibodies to BP180 and BP230 can be detected by indirect immunofluorescence (IIF) on different substrates (oesophagus, salt-split-skin, BP180-antigen dots, BP230-transfected cells) and ELISA. Here, we compared test characteristics of these test systems.We analysed sera from BP patients (n=60) in whom the clinical diagnosis had been confirmed histopathologically. The control cohort comprised sera from patients with other autoimmune-associated (n=22) or inflammatory (n=35) skin diseases. All samples were tested by IIF (EUROIMMUN™ Dermatology Mosaic) and ELISA (EUROIMMUN and MBL).Anti-BP180 is best detected with BP180-antigen dots by IIF (sensitivity: 88%; specificity: 97%). As compared to IIF, the differences with both BP180 ELISA techniques are small though. Likelihood ratios (LRs) for positive and negative test results are >10 and between 0.1 and 0.2, respectively, for all test systems. Detection of anti-BP230 is highly variable (sensitivity range 38–60%; specificity range 83–98%). Only the IIF test reveals a LR for positive test results >10. Since the LRs for a negative test are all ~0.5, negative test results for anti-BP230 antibodies do not help to exclude BP.In conclusion, the multi-parameter IIF test reveals a good diagnostic performance in BP. Since this test simultaneously allows for the detection of anti-Dsg1 and anti-Dsg3 antibodies, involved in pemphigus foliaceus and vulgaris, a single test-incubation may be sufficient to differentiate between the most frequent autoimmune blistering diseases.

Five Japanese cases of antidesmoglein 1 antibody‐positive and antidesmoglein 3 antibody‐negative pemphigus with oral lesions

Oral mucosal lesions develop in pemphigus vulgaris, but not in pemphigus foliaceus. This clinical phenomenon is explained by the 'desmoglein (Dsg) compensation theory'. Dsg3 and Dsg1 are major autoantigens for pemphigus vulgaris and pemphigus foliaceus, respectively. Dsg3 is overexpressed and Dsg1 is weakly expressed on the oral mucosa. Thus, on the oral mucosa, suppression of Dsg3 function by anti-Dsg3 autoantibodies is not compensated by weakly expressed Dsg1 in pemphigus vulgaris, while suppression of Dsg1 function by anti-Dsg1 autoantibodies is perfectly compensated by richly expressed Dsg3 in pemphigus foliaceus. We present five Japanese patients with pemphigus who deviate from this theory, i.e. all patients showed oral lesions (three also had cutaneous lesions) and reacted only with Dsg1, but not with Dsg3, by enzyme-linked immunosorbent assay. To confirm whether the unique clinical phenotypes in our patients were due to a different immunological profile from that in classical pemphigus, we examined the reactivity of the patient sera by immunoprecipitation-immunoblotting analysis using five Dsg1/Dsg2 domain-swapped molecules. The sera of two patients who had only oral lesions tended to react with the extracellular (EC) 5 domain of Dsg1, the domain that is considered nonpathogenic in classical pemphigus foliaceus. Sera of three patients with mucocutaneous lesions reacted with EC1 domain or with both EC1 and EC2 domains of Dsg1, like classical pemphigus foliaceus. These results indicate that antigenic diversity of anti-Dsg1 antibodies in these patients may cause the unique oral mucosal and cutaneous lesions, although further studies are required to elucidate the pathomechanisms.

Epitope Spreading Is Rarely Found in Pemphigus Vulgaris by Large-Scale Longitudinal Study Using Desmoglein 2–Based Swapped Molecules

Epitope spreading is involved in inducing and maintaining self-reactivity. Epitope spreading in pemphigus vulgaris (PV), caused by IgG autoantibodies to desmoglein 3 (Dsg3) and Dsg1, was previously analyzed using Dsg3/Dsg1 extracellular domain-swapped molecules. However, precise identification of the responsible epitopes in each molecule by using only this method was problematic. In this study, we studied epitope spreading in PV by a novel immunoprecipitation-immunoblot method using Dsg3 (or Dsg1)/Dsg2 domain-swapped molecules, which overcomes the problems associated with the previous approaches. We analyzed the antigenic epitopes recognized by 212 sera collected from 53 PV patients at multiple disease stages. The major epitopes were present at the N-terminal region of Dsgs and were unchanged over the course of the disease in both anti-Dsg3 mucosal dominant-type PV and anti-Dsg3/Dsg1 mucocutaneous-type PV. These N-terminal epitopes were calcium dependent. Circulating antibodies in paraneoplastic pemphigus and pemphigus herpetiformis had unique epitope distributions, although the Dsg N-termini still contained the major epitopes. These results suggest that, after onset, intramolecular and intermolecular epitope spreading among extracellular domains on Dsg3 and Dsg1 is rare in PV and has no correlation with disease course.

Pathogenic Anti-Desmoglein 3 mAbs Cloned from a Paraneoplastic Pemphigus Patient by Phage Display

Paraneoplastic pemphigus (PNP) is an autoimmune blistering disease associated with lymphoproliferative neoplasms and characterized by antibodies against plakins and desmoglein 3 (Dsg3). Anti-Dsg3 antibodies have a primary role in blister formation in PNP. In this study, we used phage display to clone monoclonal anti-Dsg3 antibodies from a PNP patient to further characterize their pathogenicity. We isolated 20 unique Dsg3-reactive mAbs, which we classified into four groups according to the heavy-chain complementarity-determining region 3 (CDR3) region. Genetic analyses demonstrated that three antibody groups used the VH1-46 gene (18 clones) and one group used the VH1-02 gene (2 clones). The results of an in vitro keratinocyte dissociation assay and a human skin organ culture injection assay showed that three antibodies displayed pathogenic activity in blister formation with different potencies. Epitope mapping using domain-swapped Dsg3/Dsg2 showed that these pathogenic mAbs bound Ca(2+)-dependent conformational epitopes in the middle portion of the extracellular region of Dsg3 (EC2 and EC3 domains), in contrast to most previously characterized pathogenic pemphigus vulgaris antibodies, which bound to the EC1 domain of Dsg3. These mAbs reflect the unique polyclonal nature of anti-Dsg3 antibodies in PNP and represent an important tool for detailing the pathophysiological mechanisms of blister formation in PNP.

An Adult Passive Transfer Mouse Model to Study Desmoglein 3 Signaling in Pemphigus Vulgaris

Evidence has accumulated that changes in intracellular signaling downstream of desmoglein 3 (Dsg3) may play a significant role in epithelial blistering in the autoimmune disease pemphigus vulgaris (PV). Currently, most studies on PV involve passive transfer of pathogenic antibodies into neonatal mice which have not finalized epidermal morphogenesis, and do not permit analysis of mature hair follicles (HFs) and stem cell niches. To investigate Dsg3 antibody-induced signaling in the adult epidermis at defined stages of the HF cycle, we here developed a model with passive transfer of the monospecific pathogenic Dsg3 antibody AK23 into adult 8-week-old C57Bl/6J mice. Validated using histopathological and molecular methods, we found that this model faithfully recapitulates major features described in PV patients and PV models. Two hours after AK23 transfer we observed widening of intercellular spaces between desmosomes and EGFR activation, followed by increased Myc expression and epidermal hyperproliferation, desmosomal Dsg3 depletion and predominant blistering in HFs and oral mucosa. These data confirm that the adult passive transfer mouse model is ideally suited for detailed studies of Dsg3 antibody-mediated signaling in adult skin, providing the basis for investigations on novel keratinocyte-specific therapeutic strategies.

Comparison of immunological parameters in patients with pemphigus vulgaris following rituximab and IVIG therapy

Information on certain immunological parameters in patients with pemphigus vulgaris (PV) treated with rituximab (RTX) and intravenous immunoglobulin (IVIG) therapy is limited. Comparing immunological parameters in patients who achieved long-term clinical remission (LTR) with those who relapsed. Retrospective analysis of 19 patients treated at a single centre using the same protocol. Comparisons were made between patients who went into LTR and those who relapsed following completion of the protocol. Treatments prior to IVIG and RTX included prednisone with or without an immunosuppressive agent. The immunological parameters measured included peripheral blood B cells (CD19+), serum quantitative immunoglobulin levels, and levels of antibodies to desmogleins (Dsg) 1 and 3. Eleven patients achieved LTR. Eight patients developed 15 relapses. The mean follow-up time for the LTR group was 29·6±11·2months, and for the relapse group, 40·0±7·0 months. There were no significant differences in times to B-cell depletion, repopulation, or recovery to pretreatment levels between the patients who achieved LTR and those who relapsed. Recurrences usually occurred after B-cell repopulation. Repeated treatments did not influence the time to B-cell repopulation. IgM levels were decreased after therapy and remained decreased. A consistent increase in anti-Dsg1 antibody levels occurred at the time of relapse in patients with mucocutaneous disease. The majority of patients treated with rituximab and IVIG therapy achieved LTR. Retreatment of relapses can induce LTR. Decreased serum IgM levels persisted following treatment. Increases in anti-Dsg1 antibodies during therapy in patients with mucocutaneous disease suggests a close follow-up for a potential relapse is required.

Efficacy and safety of rituximab treatment in Indian pemphigus patients

Pemphigus is a potentially fatal autoimmune epidermal bullous disorder. Various treatment modalities have been described to treat pemphigus. In cases where the disease fails to respond to conventional therapy, rituximab has been shown to be effective. To study the efficacy of rituximab in the treatment of resistant or severe pemphigus in Indian patients. Patients with pemphigus were treated with intravenous rituximab 1000 mg in adults or 375 mg/m(2) body surface area in children by two doses, 15 days apart in this open labelled pilot study. Anti-desmoglein1 (anti-Dsg1) antibodies and anti-desmoglein3 (anti-Dsg3) antibodies were measured at the start of therapy and at the end of the follow-up period. The outcome was studied in terms of control of disease activity (CD), complete remission (CR), partial remission (PR) and time to disease control (TDC) as defined by the consensus statement from the International Pemphigus Committee. A total of 9 (90%) of 10 patients responded to the treatment. Three (30%) had CR of disease and were off all treatment. Four (40%) patients had CR and were on low dose oral prednisolone. Two (20%) patients had PR and were on low dose prednisolone. One patient died of sepsis. The mean TDC was 8 weeks. Response to treatment showed good correlation with index values of anti-Dsg1 antibody. Infusion-related angioedema and sepsis were seen as complications due to rituximab administration. Rituximab is effective in treating resistant and severe pemphigus in Indian patients. Acute complications can occur during rituximab infusion and require close monitoring.

Cognate Th2–B Cell Interaction is Essential for the Autoantibody Production in Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a Th2-dominant autoimmune skin disease. We showed that indeed active PV patients had a biased Th2 response and specific IgG4 autoantibodies were dominant. To further investigate the role of antigen-specific Th2 cells in the regulation of pathogenic Dsg3-IgG antibody production, we used recombined Dsg3 protein to immunize wild-type C57BL/6 mice with aluminum hydroxide or complete Freund's adjuvant as adjuvant. CD4(+) T cells from Dsg3-immunized mice were adoptively transferred into TCR-β chain deficient mice. The transferred CD4(+) T cells were readily seen in the peripheral blood and spleen, and interacted with B cells, resulting in B-cell activation. Furthermore, transferred CD4(+) T cells from mice immunized with Dsg3 plus Alum with Th2 phenotype were able to render unprimed B cells to secrete Dsg3-specific IgG1 antibody in vivo. Taken together, these results provide the first demonstration of direct role of Dsg3-reactive CD4(+) T (Th2) cells in the regulation of pathologic anti-Dsg3 antibody production.

Recurrent staphylococcal infection of the face associated with the development of anti-Dsg3 antibody response

The etiopathogenesis of the Tunisian pemphigus is still ambiguous. Indeed, the complete mechanism, which goes from the causal agent until the final targets, is unknown. Nevertheless, two types of factors were associated in the etiopathogenesis of the pemphigus: genetic and/or environmental factors. We focused our intention in bacterial infectious etiology due to staphylococcus. We report a 42-year-old man presenting staphylococcal infection: anti-desmogleines antibody (1 and 3) at the first infection was negative. Surprisingly, he became positive for anti-Dsg3 antibodies after having relapsed.

Analysis of 6 cases of drug-induced pemphigus

To study clinical and laboratory characteristics of drug-induced pemphigus. Using direct immunofluorescence (IF), indirect IF, ELISA and immunoblotting to characterize 6 patients with drug-induced pemphigus (DIP) and compared them with 20 cases of idiopathic pemphigus. All the 6 cases of DIP showed obvious itching (100%) and no damage to the oral mucosa. Five out of 6 DIP cases (83.33%) presented as pemphigus folicaeus (PF) since they contained circulating Dsg1-specific IgG, were sensitive to low doses of glucocorticoid, and had good prognosis. One case was showed as pemphigus vulgaris (PV). Dsg1-specific IgA was positive in peripheral blood of 4 cases (66.67%), and the antibody disappeared after treatment. In patients with idiopathic pemphigus, only 6 cases (30%) had mild itching, and 12 cases (60%) had oral mucosal lesions. Twelve cases (60%) were PV with anti-Dsg1 and -Dsg3 antibodies, and 8 cases (40%) were PF with anti-Dsg1 antibody only. One case (5%) had anti-Dsg1 IgA. Drug factors should be considered for pemphigus as some common antibiotics can cause pemphigus.

PTPN22 1858T is not a risk factor for North American Pemphigus vulgaris

Alterations in the protein tyrosine phosphatase N22 (PTPN22) gene affect the threshold for lymphocyte activation. The PTPN22 1858T polymorphism leads to uninhibited T-cell receptor cascade propagation. An elevated PTPN22 1858C/T genotype frequency has been correlated with several autoimmune disorders which have T-cell and humoral components. However, a recent Tunisian report demonstrated no association between PTPN22 1858T and patients with Pemphigus vulgaris (PV), an autoantibody-associated blistering disorder. Because PTPN22 1858T allele frequency is known to vary across ethnic populations, we conducted a case-control study investigating the relationship between PTPN22 1858T and PV in North American patients of either Ashkenazi Jewish or Caucasian (non-Ashkenazi) decent. Participant genotype was determined in 102 PV patients and 102 healthy controls by restriction fragment length polymorphism-polymerase chain reaction genotyping. Relationships were calculated using Fisher's exact tests and chi-squared tests. We report that the PTPN22 1858C/T genotype is not significantly associated with PV in either Caucasians (P = 0.83) or Ashkenazi Jews (P = 0.60). Further stratification of the patient population by gender, age of disease onset, HLA-type, family history of autoimmune disease, history of anti-desmoglein (anti-Dsg) 3 or anti-Dsg1 antibody response, history of lesion morphology, and disease duration did not uncover significant associations between the PTPN22 1858T allele and PV subgroups. Our data indicate that the PTPN22 1858T mutation is not associated with PV in the North American population. We do observe an elevation of PTPN22 1858C/T genotype frequency in male PV patients. Further investigation will be required to determine if this trend reaches significance in larger studies.

Antigen-independent development of Foxp3+ regulatory T cells suppressing autoantibody production in experimental pemphigus vulgaris

The CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play suppressive roles in various types of autoimmunity. It has been reported that Tregs develop in the thymus after high-affinity interaction of their TCR with self-peptide/MHC ligands mostly utilizing TCR-transgenic system. In this study, we examined whether the specific antigen is involved in the development of polyclonal Tregs in pemphigus vulgaris (PV), an autoimmune blistering disease caused by anti-desmoglein 3 (Dsg3) IgG antibodies, as a model system. Adoptive transfer of splenocytes of Dsg3(-)(/-) mice immunized with recombinant mouse Dsg3 to Rag2(-)(/-) recipient mice expressing Dsg3 resulted in the stable production of anti-Dsg3 IgG and the development of PV phenotypes. We show here that Tregs control anti-Dsg3 antibody production in PV model mice: the adoptive transfer of Tregs and the depletion of endogenous Tregs suppressed and augmented, respectively, the anti-Dsg3 antibody production. To examine whether the endogenous expression of Dsg3 is involved in the generation of these PV-relevant Tregs, we compared the potential of wild-type Tregs with that of Tregs from Dsg3(-)(/-) mice. Polyclonal Tregs from Dsg3(-)(/-) mice were more potent than that of wild-type mice, in both adoptive transfer and Treg-depletion experiments, while suppressive activities against IgG production against an irrelevant antigen were similar between Tregs from wild-type and Dsg3(-)(/-) mice. Our observation implies that Tregs capable of suppressing T(h) cells that drive autoantibody production can develop in the absence of the target antigen.

Transgenic rescue of desmoglein 3 null mice with desmoglein 1 to develop a syngeneic mouse model for pemphigus vulgaris

An active disease mouse model of pemphigus vulgaris (PV) was developed using the adoptive transfer of splenocytes from Dsg3(-/-) mice with a mixed C57BL/6J (B6) and 129/Sv genetic background into B6-Rag2(-/-) mice. Further immunological investigation is needed to resolve the genetic mismatch between host and recipient mice. The B6-Dsg3(-/-) mice did not grow old enough to provide splenocytes, probably due to severe oral erosions, with resulting inhibition of food intake. To rescue the B6-Dsg3(-/-) mice and to produce syngeneic PV model mice. Transgenic expression of mouse Dsg1 was attempted to compensate for the genetic loss of Dsg3 using the keratin 5 promoter. We evaluated the compensatory ability of Dsg1 in vivo by comparing Dsg1(wt/wt), Dsg1(tg/wt), and Dsg1(tg/tg) mice. We generated a PV model via the adoptive transfer of B6-Dsg1(tg/tg)Dsg3(-/-) splenocytes to B6-Rag2(-/-) mice. Dsg1(tg/tg) and Dsg1(tg/wt) mice expressed ectopic Dsg1 on keratinocyte cell surfaces in the lower layers of the epidermis, oral epithelium, and telogen hair follicles. Ectopic Dsg1 blocked the pathogenic effects of AK23 anti-Dsg3 mAb, and improved the body weight loss, telogen hair loss, and survival rate dose-dependently. While the B6-Dsg1(wt/wt)Dsg3(-/-) mice died by week 2, over 80% of the B6-Dsg1(tg/tg)Dsg3(-/-) mice survived at week 6. Furthermore, the syngeneic PV model mice showed the characteristic phenotype, including stable anti-Dsg3 antibody production and suprabasilar acantholysis on histology. Transgenic expression of Dsg1 rescued the severe B6-Dsg3(-/-) phenotype and provided a syngeneic mouse model of PV, which may be a valuable tool for clarifying immunological mechanisms in autoimmunity and tolerance of Dsg3.

Correlation between disease activity and pemphigus-specific antibody subclasses in patients with pemphigus

Objective To assess the correlation between the subclasses of antibodies against desmoglein (Dsg) 1 and Dsg3 and disease activity in patients with pemphigus. Methods Sera were collected from 47 patients with pemphigus, and ELISA was performed to determine the titers and subclasses of antibodies against Dsg1 and Dsg3. The correlation of antibody titers and subclasses with disease activity was assessed.Results Clinical phenotype was associated with antibody profiles in these patients with pemphigus. Of 17 patients with mucocutaneous involvement, 14 (82.4%) had both anti-Dsg3 and anti-Dsg1 antibodies; of 16 patients with cutaneous involvement, 15 (93.7%) had anti-Dsg1 antibody, only 1 (6.3%) developed anti-Dsg3 antibody; of 6 patients with mucosal involvement, all ( 100% ) had only anti-Dsg3 antibody. The serum levels of antibodies against Dsg1 and Dsg3 were increased, but not in parallel with the disease severity in these patients.Moreover, the subclasses of antibodies were correlated with disease severity. IgG4 subclass antibodies against Dsg1 and Dsg3 predominated in patients with pemphigus at active stage, whereas IgG1 subclass in those at remission stage. The serum levels (expressed as absorbance value) of IgG4 and IgG1 subclass antibodies were 1.92 ± 1.21 and 0.60 ± 0.61 respectively, with the ratio of IgG4 to IgG1 more than 1, in patients with antiDsg1 antibodies at active stage, 0.03 ± 0.02 and 0.22 ± 0.11 respectively with the ratio of IgG4 to IgG1 less than 1, in those at remission stage, 2.35 ± 2.17 and 1.84 ± 1.16 respectively with the ratio of IgG4 to IgG1 more than 1 in patients with anti-Dsg3 antibodies at active stage, 0.15 ± 0.16 and 1.05 ± 0.77 respectively with the ratio of IgG4 to IgG1 less than 1 in those at remission stage. Conclusions The subclasses of pemphigus-specific antibodies are closely correlated with the disease severity in patients with pemphigus. The detection of subclasses and titers of anti-Dsg1 and anti-Dsg3 antibodies may aid in the diagnosis of and monitoring of disease severity in pemphigus. Key words: Pemphigus; Autoantibodies; Severity of illness index; Enzyme-linked immunosorbent assay

Catabolism of pemphigus foliaceus autoantibodies by high-dose IVIg therapy

High-dose intravenous immunoglobulin (HD-IVIg) has several distinguishing therapeutic characteristics. However, a certain number of pemphigus cases have been experienced, which did not respond to HD-IVIg. This is the first case report that the serum level of anti-desmoglein (Dsg)1 antibody rebounded, critically associated with IgG serum level. We describe a patient with pemphigus foliaceus (PF), unresponsive to oral prednisolone followed by pulse therapy and double-filtration plasmapheresis, in whom clinical remission was induced by 4 courses of HD-IVIg. Anti-Dsg1 antibody levels, serum IgG and disease activity were monitored. Anti-Dsg1 antibody titers rapidly decreased after IVIg treatment when total IgG levels were high; however, the serum level of anti-Dsg1 antibody rebounded as the total IgG level returned to normal. The levels of anti-Dsg1 antibody were decreased for an average of 13.7 days after treatment. The therapeutic effect of IVIg treatment was associated with an increased serum level of total IgG. IVIg therapy reduced the titers of autoantibody by accelerating the catabolism of immunoglobulin induced by high IgG serum levels. IVIg itself appears to accelerate IgG degradation rather than suppress IgG production. Sufficient suppression of antibody production is critical for successful treatment with IVIg.

Human leukocyte antigen genotypes and antibody profiles associated with familial pemphigus in Japanese

Previous population-based, genetic studies have shown that human leukocyte antigen (HLA) class II loci such as HLA-DR4 (DRB1*04) and HLA-DR14 (DRB1*14) alleles are consistently associated with the occurrence of pemphigus vulgaris (PV) in Japanese as well as other ethnic populations. Among PV-related HLA-DRB1 alleles (*0406, *1401, *1405, *1406) in Japan, HLA DRB1*1405 and DRB1*0406 were found to be associated with both PV and pemphigus foliaceus (PF) phenotypes. We report four familial cases of pemphigus in two unrelated families, together with analysis of their HLA-DR and -DQ alleles, and their antibody profiles. One family comprised a woman with PF and her mother with PV: both patients shared a HLA haplotype of A31(19), B54(22), CW1 and DRB1*1405. Another family included two sisters with PF and PV, respectively: both of these patients shared a DRB1*1405-DQA1*0104-DQB1*0503 haplotype. Clinicopathological and serological monitoring revealed that the elder sister with PF presented with a PV phenotype later, and gained anti-desmoglein (Dsg)3 antibodies in addition to having a low titer of anti-Dsg1 antibodies. Conversely, the younger sister with PV developed PF with only anti-Dsg1 antibody detected. These results indicate that an HLA-DRB1*1405 (DQB1*0503) haplotype may confer susceptibility to both PV and PF, and that genetic susceptibility alone is not always responsible for the clinical phenotype and autoantibody profile.

Recalcitrant facial pemphigus vulgaris: correlation of skin lesions with the ratio of antidesmoglein antibodies 1 and 3

Pemphigus vulgaris (PV) is an autoimmune bullous disease characterized by autoantibodies against desmogleins. We report a case of recalcitrant PV, which progressed from the mucosal to the mucocutaneous type, with a corresponding increase in anti-desmoglein (Dsg)1 and decrease in anti-Dsg3 antibody titres. Thus, the clinical features seemed to correlate with the ratio of anti-Dsg1 and 3. The patient also had anti-Dsg4 antibodies, which might be related to the nonscarring diffuse hair loss and marked facial involvement she also had. The patient did not respond to treatment with systemic steroid, ciclosporin, azathioprine, cyclophosphamide or double filtration plasmapheresis, and eventually died from fulminant thrombotic thrombocytopenic purpura of unknown cause.

Confirmation of a disease model of pemphigus vulgaris: characterization and correlation between disease parameters in 90 mice

Pemphigus vulgaris (PV) is a chronic autoimmune bullous disease associated with immunoglobulin G (IgG) autoantibodies against desmoglein 3 (Dsg3). Previously, a mouse model of PV was established by adoptive transfer of naive splenocytes from Dsg3(-/-) mice to Rag2(-/-) mice. The model is unique as Dsg3-specific naive lymphocytes from Dsg3(-/-) mice can be primed and activated by the endogenous Dsg3 in recipient mice, resulting in pathogenic anti-Dsg3 IgG without any active immunization. Here, we show that PV occurs after both intravenous (i.v.) and intraperitoneal (i.p.) transfer of naive splenocytes. We evaluated the robustness of the model by comparing engraftment as well as PV phenotype using several disease parameters. While engraftment of spleen cells was significantly better after i.p. transfer, anti-Dsg3 IgG antibody production, IgG deposition and disease score were comparable after both i.v. and i.p. cell transfer. Thus, transferred cells can be primed, activated and gain effector function. However, we detected heterogeneity in disease development, as only 46% of the mice developed hair loss, whereas 76% of the mice developed anti-Dsg3 IgG. We also tested cyclophosphamide in the model, as this drug is reported to be beneficial to PV patients. Cyclophosphamide significantly inhibited disease development in a preventive setting, and mice were free of symptoms 35 days after discontinuing the treatment. We have successfully confirmed the induction of PV after both i.v. and i.p. transfer. In addition, we have shown that this model can be used for evaluation of immunosuppressive drugs.

A prospective analysis of anti-desmoglein antibody profiles in patients with rheumatoid arthritis treated with thiol compounds

Drug-induced pemphigus is mainly caused by drugs containing sulfhydryl (thiol) groups in their molecules. To understand the serial alteration of anti-desmoglein (Dsg) antibody profile in patients with rheumatoid arthritis (RA) receiving thiol compounds. Anti-Dsg1 or -Dsg3 antibodies were analysed twice in a 1.6-year interval, in the same series of RA patients. Eleven of 204 serum samples (5.4%) and 6 of 139 samples (4.3%) from the same RA group showed a positive reaction against Dsg1 or Dsg3 in the first and second screening tests, respectively. The positive rates were higher than those in patients with collagen diseases including systemic lupus erythematosus, Sjögren syndrome, mixed connective tissue disease, and systemic sclerosis. In comparison with the results in the first and second screening tests, one RA patient newly gained anti-Dsg3 antibody, and at least 4 patients lost the antibodies in 1.6 years. Three patients produced antibodies to Dsg1 and/or Dsg3 in a similar fashion as did in the first screening tests. Only one RA serum sample exhibited an intercellular reactivity to human skin or monkey esophagus by immunofluorescence, and another sample bound to a 130 kDa protein suggestive of Dsg3 by immunoblotting. Most anti-Dsg antibodies in RA patients recognized EDTA-resistant epitopes of Dsg different from EDTA-sensitive epitopes recognized by pemphigus sera. RA patients receiving any of the thiol compounds may gain autoantibodies to non-conformational epitopes of either Dsg1 or Dsg3, and that such autoantibodies alone are not capable of inducing acantholysis.