HLA class II antigens are associated with Japanese pemphigus patients

HLA Haplotypes and Class II Molecular Alleles in Argentinian Patients with Pemphigus Vulgaris

Background:

Pemphigus is a group of chronic blistering autoimmune diseases of which pemphigus vulgaris (PV) is the more frequent clinical form. The association of PV with the HLA serotypes suggests that there is a genetic predisposition to the disease.

Objectives:

To determine the frequency of class I and class II HLA antigens and the allelic variants of the class II HLA antigens, DR and DQ, in patients with PV and to determine the relative risk.

Methods:

An observational, prospective, transverse, and controlled study carried out between 1995 and 1999. Forty-seven patients with a diagnosis of PV and a control sampling of 199 unselected individuals from the same ethnic group were included. The HLA alleles were determined by polymerase chain reaction.

Results:

No significant associations were detected between HLA A, B, or C and our patients. The DR and DQ molecular alleles positively associated with PV were two different haplotypes: DRβ1* 0402/DQβ1* 0302 and DRβ1* 1401/DQβ1* 0503.

Conclusions:

In patients with the haplotype DRβ1* 0402/DQβ1* 0302 the affectation of 10%–30% of the corporal surface prevailed (ACS). In patients with DRβ1* 1401/DRQβ1* 0503, involvement of <10% of the ACS prevailed.

Epidemiology of pemphigus vulgaris in the Northeast China: a 10-year retrospective study

The aim of the present study was to evaluate the incidence, epidemiological, clinical and therapeutic features of patients with pemphigus vulgaris in China. We retrospectively investigated a total of 221 patients with pemphigus vulgaris. The parameters including age at diagnosis/onset, sex, diagnostic methods, hospitalizations, side-effects with different treatments, pemphigus vulgaris-associated diseases, the therapeutic features and duration of follow up were evaluated. The male : female ratio was 1:1.40. The incidence rate was obviously higher in two age groups, 31-40 years and 41-50 years. The mean age at onset was 44.19 ± 21.45 years. The majority of patients (56.56%) presented the mucocutaneous type. In addition, we found that various doses of corticosteroids (including the mean initial dose, maximum control dose, total dose before reducing and hospitalized total dose) exhibited statistical differences between only corticosteroids and corticosteroids-immunosuppressant groups in mild, moderate and severe pemphigus vulgaris (P < 0.05). Our survey suggested that pemphigus vulgaris most frequently occurred in the 41-50-year age group in China and the majority of patients manifested mucocutaneous lesions. Importantly, the incidence rate in females was higher than in males. The patients who needed combined immunosuppressant treatment, usually needed higher doses of corticosteroids initially, to control the disease and over the total course of treatment.

Pemphigus autoimmunity: hypotheses and realities

The goal of contemporary research in pemphigus vulgaris and pemphigus foliaceus is to achieve and maintain clinical remission without corticosteroids. Recent advances of knowledge on pemphigus autoimmunity scrutinize old dogmas, resolve controversies, and open novel perspectives for treatment. Elucidation of intimate mechanisms of keratinocyte detachment and death in pemphigus has challenged the monopathogenic explanation of disease immunopathology. Over 50 organ-specific and non-organ-specific antigens can be targeted by pemphigus autoimmunity, including desmosomal cadherins and other adhesion molecules, PERP cholinergic and other cell membrane (CM) receptors, and mitochondrial proteins. The initial insult is sustained by the autoantibodies to the cell membrane receptor antigens triggering the intracellular signaling by Src, epidermal growth factor receptor kinase, protein kinases A and C, phospholipase C, mTOR, p38 MAPK, JNK, other tyrosine kinases, and calmodulin that cause basal cell shrinkage and ripping desmosomes off the CM. Autoantibodies synergize with effectors of apoptotic and oncotic pathways, serine proteases, and inflammatory cytokines to overcome the natural resistance and activate the cell death program in keratinocytes. The process of keratinocyte shrinkage/detachment and death via apoptosis/oncosis has been termed apoptolysis to emphasize that it is triggered by the same signal effectors and mediated by the same cell death enzymes. The natural course of pemphigus has improved due to a substantial progress in developing of the steroid-sparing therapies combining the immunosuppressive and direct anti-acantholytic effects. Further elucidation of the molecular mechanisms mediating immune dysregulation and apoptolysis in pemphigus should improve our understanding of disease pathogenesis and facilitate development of steroid-free treatment of patients.

Immunological hotspots analyzed by docking simulations: evidence for a general mechanism in pemphigus vulgaris pathology and transformation

Background

Pemphigus vulgaris (PV) is an acquired autoimmune blistering disorder in which greater than 80% of active patients produce autoantibodies to the desmosomal protein desmogelin 3 (Dsg3). As the disease progresses, 40–50% of patients may also develop reactivity to a second component of the desmosomal complex, desmogelin 1 (Dsg1). T cells are clearly required for the production of autoantibodies in PV. However, few T-cell specificities within Dsg3 or Dsg1 have been reported to date, and the precise role of T-cells in disease pathogenesis and evolution remains poorly understood. In particular, no studies have addressed the immunological mechanisms that underlie the observed clinical heterogeneity in pemphigus. We report here a structure-based technique for the screening of DRB1*0402-specific immunological (T-cell epitope) hotspots in both Dsg3 and Dsg1 glycoproteins.

Results

High predictivity was obtained for DRB1*0402 (r² = 0.90, s = 1.20 kJ/mol, q² = 0.82, s_press = 1.61 kJ/mol) predictive model, compared to experimental data. In silico mapping of the T-cell epitope repertoires in Dsg3 and Dsg1 glycoproteins revealed that the potential immunological hotspots of both target autoantigens are highly conserved, despite limited sequence identity (54% identical, 72% similar). A similar number of well-conserved (18%) high-affinity binders were predicted to exist within both Dsg3 and Dsg1, with analogous distribution of binding registers.

Conclusion

This study provides interesting new insights into the possible mechanism for PV disease progression. Our data suggests that the potential T-cell epitope repertoires encoded in Dsg1 and Dsg3 is substantially overlapping, and it may be possible to apply a common, antigen-specific therapeutic strategy with efficacy across distinct clinical phases of disease.

Case of pemphigus foliaceus that shifted into pemphigus vulgaris after adrenal tumor resection

A 79-year-old Japanese woman visited our hospital on 6 May 2003, who had suffered from erythema and crusted vesicles located on the head, face and trunk. The eruptions first appeared in February 2003. Histopathological findings included blister formation spreading from just below the horny layers to the upper squamous layers, where acantholytic cells were observed. Direct immunofluorescence disclosed immunoglobulin G depositions in the epidermal intercellular spaces. Enzyme-linked immunosorbent assay showed an elevated titer of anti-desmoglein (Dsg)1 autoantibodies (154 index value), but almost normal levels of anti-Dsg3 autoantibodies (8 index value in serum). The diagnosis at first was made as pemphigus foliaceus (PF). Topical use of corticosteroids alone could control the eruptions well. Systemic examinations on admission revealed a right adrenal tumor that had caused Cushing's syndrome. Its resection was performed on 24 July 2003. Histopathological diagnosis of the removed tumor was a functional adrenal adenoma. The symptoms had worsened after the resection. Topical use of corticosteroids alone could no longer control the symptoms. Additional p.o. medications of minocycline hydrochloride and nicotinic acid amides improved the symptoms to some extent. However, oral cavity erosions appeared in December 2004, and the titer of anti-Dsg3 autoantibodies in serum elevated, suggesting a transition from PF to pemphigus vulgaris (PV). p.o. administration of corticosteroids started, which improved the symptoms significantly. To date, there have been no reports of pemphigus complicated with an adrenal tumor that caused Cushing's syndrome in Japan. The present case is particularly interesting in that the symptoms became worse after the tumor resection and that the first diagnosis of PF shifted into PV after the operation.

Prediction of desmoglein-3 peptides reveals multiple shared T-cell epitopes in HLA DR4- and DR6-associated pemphigus vulgaris

Background

Pemphigus vulgaris (PV) is a severe autoimmune blistering skin disorder that is strongly associated with major histocompatibility complex class II alleles DRB1*0402 and DQB1*0503. The target antigen of PV, desmoglein 3 (Dsg3), is crucial for initiating T-cell response in early disease. Although a number of T-cell specificities within Dsg3 have been reported, the number is limited and the role of T-cells in the pathogenesis of PV remains poorly understood. We report here a structure-based model for the prediction of peptide binding to DRB1*0402 and DQB1*0503. The scoring functions were rigorously trained, tested and validated using experimentally verified peptide sequences.

Results

High predictivity is obtained for both DRB1*0402 (r² = 0.90, s = 1.20 kJ/mol, q² = 0.82, s_press = 1.61 kJ/mol) and DQB1*0503 (r² = 0.95, s = 1.20 kJ/mol, q² = 0.75, s_press = 2.15 kJ/mol) models, compared to experimental data. We investigated the binding patterns of Dsg3 peptides and illustrate the existence of multiple immunodominant epitopes that may be responsible for both disease initiation and propagation in PV. Further analysis reveals that DRB1*0402 and DQB1*0503 may share similar specificities by binding peptides at different binding registers, thus providing a molecular mechanism for the dual HLA association observed in PV.

Conclusion

Collectively, the results of this study provide interesting new insights into the pathology of PV. This is the first report illustrating high-level of cross-reactivity between both PV-implicated alleles, DRB1*0402 and DQB1*0503, as well as the existence of a potentially large number of T-cell epitopes throughout the entire Dsg3 extracellular domain (ECD) and transmembrane region. Our results reveal that DR4 and DR6 PV may initiate in the ECD and transmembrane region respectively, with implications for immunotherapeutic strategies for the treatment of this autoimmune disease.

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.

Higher prevalence of human herpesvirus 8 DNA sequence and specific IgG antibodies in patients with pemphigus in China

BACKGROUND

Environmental factors, including virus infection, may play a role in the onset and/or development of pemphigus. However, it is controversial whether human herpesvirus (HHV)-8 is involved in pathogenesis of pemphigus.

OBJECTIVE

The possible association of pemphigus with HHV-8 was investigated.

METHODS

A total of 36 lesional skin and 13 peripheral blood mononuclear cell specimens from 58 patients with pemphigus, and 18 normal skin and 230 peripheral blood mononuclear cell specimens from healthy individuals, were tested for HHV-8 DNA sequence by a nested polymerase chain reaction assay. In all, 29 sera from the patients and 109 sera from healthy individuals were tested for HHV-8-specific IgG antibodies by enzyme-linked immunosorbent assays using HHV-8-specific oligopeptides as antigens.

RESULTS

Prevalence of both HHV-8 DNA sequence (36.1% and 30.8% in lesional skin and in peripheral blood mononuclear cells, respectively) and HHV-8-specific IgG antibodies (34.5%) for patients with pemphigus was statistically higher than that of control subjects (<8% in both assays). There was no significant difference in HHV-8 prevalence among different types of pemphigus.

CONCLUSION

HHV-8 infection might be a contributing factor in the development of pemphigus.

Recent advances in the study of the pathophysiology of pemphigus

Recent rapid advances in the basic research into pemphigus have provided many insights into its pathophysiology. In particular, a recently developed enzyme-linked immunosorbent assay (ELISA) for desmogleins 1 and 3 (Dsg1 and Dsg3), antigens for pemphigus foliaceus (PF) and pemphigus vulgaris (PV), respectively, has led to great progress in the diagnosis and classification of pemphigus, as well as in understanding its pathomechanisms. Studies with the anti-Dsg1 and anti-Dsg3 antibodies have indicated that there are two types of PV, the mucosal dominant type and the mucocutaneous type. The same ELISA has identified the antigens in pemphigus herpetiformis. The autoantigens detected by this ELISA correlate well with the clinical features in pemphigus patients in showing the shift between PV and PF. In addition, the Dsg compensation theory proposed by Stanley and Amagai can reasonably explain the different depths of skin lesions and the different occurrences of skin and oral mucosal lesions between PV and PF. Furthermore, a complicated profile of autoantigens in paraneoplastic pemphigus (PNP) has been indicated in various biochemical studies, and IgG anti-Dsg1 and anti-Dsg3 antibodies have been detected in serum from all the PNP patients by the above ELISA. On the other hand, serum from subcorneal pustular dermatosis type IgA pemphigus patients have been shown to react with Dsc1, another type of desmosomal cadherin, by a novel cDNA transfection method. In addition, IgA anti-Dsg1 and anti-Dsg3 antibodies have been detected in a few patients with IgA pemphigus by an ELISA for IgA antibodies. Various autoimmune bullous diseases, including several types of pemphigus, are the only diseases in which the pathogenic role of circulating autoantibodies has been confirmed using the newborn mouse animal model. Therefore, studies of the pathophysiology of pemphigus are extremely important as a paradigm for research into various types of autoimmune diseases in other fields.

Dichotomy of autoreactive Th1 and Th2 cell responses to desmoglein 3 in patients with pemphigus vulgaris (PV) and healthy carriers of PV-associated HLA class II alleles

Pemphigus vulgaris (PV) is the most severe autoimmune bullous skin disorder and is primarily associated with circulating autoantibodies (autoAb) against desmoglein 3 (Dsg3). In light of recent evidence that autoreactive T cells are critical for the induction and regulation of Ab production, the goal of this study was to characterize and quantitate autoreactive T cells in patients with PV and healthy controls. Peripheral Dsg3-reactive Th cells from 28 patients with acute-onset, chronic active, and remittent PV were quantitated by MACS secretion assay. Dsg3-reactive Th2 cells were detected at similar frequencies in all studied PV patients, while the number of autoreactive Th1 cells exceeded those of Th2 cells in chronic active PV. In contrast, healthy carriers of the PV-associated HLA class II alleles, DRB1*0402 and DQB1*0503, exhibited exclusively Dsg3-reactive Th1 cell responses, while healthy carriers of other HLA class II alleles did not. Moreover, the presence of IgG1 and IgG4 against Dsg3 was directly related to the ratio of Dsg3-reactive Th1/Th2 cells. T cell recognition of Dsg3 was restricted by HLA-DRB1*0402 and DQB1*0503 in PV patients and Dsg3-responsive healthy donors. These observations strongly suggest 1) that the appearance of Dsg3-reactive Th2 cells is restricted to patients with PV; 2) that specific HLA class II alleles that are prevalent in PV are critical for T cell recognition of Dsg3 in PV patients and Dsg3-responsive healthy donors; and 3) that autoAb production is associated with both Th1 and Th2 cells.

HLA-class 1 and class 2 antigens in Turkish patients with pemphigus

BACKGROUND

Pemphigus is an autoimmune disease which is more frequently seen in certain ethnic groups such as Jews. It is thought that exogenous factors may induce pemphigus in genetically predisposed individuals. Recent reports on HLA antigens indicate an increased frequency of HLA-class II antigens particularly HLA-DR4 among Jewish patients. Herein we investigated the antigen frequencies of HLA-A, B, C, HLA-DR and DQ in Turkish patients with pemphigus.

METHODS

HLA class I and II antigens were typed by microdroplet lymphocyte cytotoxicity test in 33 patients with pemphigus and 100 healthy individuals.

RESULTS

HLA-B35, B44, CW4, DR4, DR14, DQ8 and DQ4 antigens were significantly high in the study group whereas HLA-DR11, DQ7 and DQ2 antigens were high among the controls. The most striking differences were observed in HLA class II antigens. HLA DR14-DQ8 and HLA B35-DR14 haplotypes were the most frequently observed ones in the study group.

CONCLUSIONS

We postulate that HLA-B35, B44, CW4, DR4, DR14, DQ4 and DQ8 antigens may be responsible for susceptibility to pemphigus while HLA-DR11, DQ7 and DQ2 antigens may have a protective role in the Turkish population.

The clinical transition between pemphigus foliaceus and pemphigus vulgaris correlates well with the changes in autoantibody profile assessed by an enzyme-linked immunosorbent assay

BACKGROUND

There are a number of reports of pemphigus with clinical shifting between pemphigus foliaceus (PF) and pemphigus vulgaris (PV). On the other hand, a novel enzyme-linked immunosorbent assay (ELISA) against recombinant baculoproteins of desmoglein 1 (Dsg1) (PF antigen) and Dsg3 (PV antigen) has been established and found to be extremely sensitive and specific.

OBJECTIVES

To characterize the change in the antibody profiles in a series of pemphigus cases with mixed features of PF and PV by various methods, including the novel ELISA. Patients/methods Sera were obtained from eight cases undergoing a shift between PF and PV and three cases of coexistent PF and PV. The autoantigens were analysed by ELISA, as well as by immunofluorescence using normal human skin sections and immunoblotting using normal human epidermal extracts.

RESULTS

The results of the ELISA, immunofluorescence and immunoblotting studies showed that the transition between PF and PV correlates well with the changes of autoantibodies against either Dsg1 or Dsg3.

CONCLUSIONS

The clinical phenotype at each stage is defined by the anti-Dsg antibody profile in the serum of these pemphigus patients showing mixed features of PF and PV. In addition, ELISA using recombinant baculoproteins was particularly useful in distinguishing PF and PV.

Detection of antigen-specific B cells in patients with pemphigus vulgaris by enzyme-linked immunospot assay: requirement of T cell collaboration for autoantibody production

Patients with pemphigus vulgaris have circulating IgG autoantibodies against desmoglein 3, which inhibit cell-cell adhesion of keratinocytes and cause blister formation in the skin and mucous membrane. To examine cellular mechanisms underlying the autoantibody production in pemphigus vulgaris patients, we have successfully developed an enzyme-linked immunospot assay which was able to detect desmoglein 3-specific autoimmune B cells quantitatively. Circulating B cells producing anti-desmoglein 3 antibodies were detected exclusively in three patients with severe disease (1.3-2.3/105 peripheral blood mononuclear cells), but not in 10 patients with mild disease or in remission or in seven healthy individuals. When this enzyme-linked immunospot assay was combined with in vitro stimulation of peripheral blood mononuclear cells with pokeweed mitogen and recombinant-desmoglein 3, we could detect circulating desmoglein 3-specific memory B cells in nine of 14 patients (6.3-84. 0/105 peripheral blood mononuclear cells), but in none of 10 healthy individuals. We further analyzed the role of CD4 + T cells in promoting anti-desmoglein 3 antibody production. The in vitro anti-desmoglein 3 antibody production was abolished when CD4 + cells were depleted or when anti-HLA-DR or anti-HLA-DQ monoclonal antibody was added to the cultures. Our results demonstrated the quantitative detection of circulating "activated" and "memory" desmoglein 3-specific B cells and suggested the important part of HLA class II-restricted CD4 + T cells in the autoantibody production in pemphigus vulgaris. In addition, the enzyme-linked immunospot assay in combination with in vitro stimulation of B cells could be broadly applied to study mechanisms for autoantibody production in various autoimmune diseases.

HLA class II restriction of autoreactive T cell responses in pemphigus vulgaris: review of the literature and potential applications for the development of a specific immunotherapy

Pemphigus vulgaris (PV) is a life-threatening autoimmune bullous disease of the skin and mucous membranes which requires immunosuppressive therapy, most commonly a combination of glucocorticoids and additional immunosuppressive agents. Since the side effects of long-term immunosuppressive therapy contribute to the poor prognosis of this disorder, there is considerable interest in a more specific treatment of this severe skin disease. PV may serve as a model disease for the development of a specific immunotherapy, because its pathogenesis as well as involved immunogenetic factors are well-characterized. This review focuses on the characterization of autoreactive T cell responses to desmoglein 3 (Dsg3), the autoantigen of PV, that presumably regulate the production of autoantibodies by providing help to the autoreactive B cells. Current knowledge on T cell epitopes of Dsg3 and the HLA class II alleles that restrict Dsg3-specific autoreactive T cell responses, as well as potential applications for a specific immunotherapy of PV, are described.

Three different autoimmune bullous diseases in one family: is there a common genetic base?

We report an unusual familial occurrence of autoimmune bullous diseases. Three members of a family suffered from three different autoimmune bullous diseases: pemphigus vulgaris (PV), linear IgA disease (LAD) and cicatricial pemphigoid (CP). The HLA type was determined in five family members: all were positive for HLA-DQ5/DR6, which is reported to be associated with susceptibility to PV. The CP patient was DQ7(3) positive, which is in concordance with enhanced susceptibility to ocular CP and CP. The LAD patient was B8 and DR3 negative but positive for HLA-A1. Our study supports the hypothesis that there is a genetically transmitted susceptibility to autoimmune bullous diseases but that additional factors seem necessary actually to develop a particular disease.

Heterogeneous MHC II restriction pattern of autoreactive desmoglein 3 specific T cell responses in pemphigus vulgaris patients and normals

Pemphigus vulgaris is a life threatening bullous autoimmune disease of the skin mediated by autoantibodies against desmoglein 3 (Dsg3) on epidermal keratinocytes. Pemphigus vulgaris patients exhibit T cell responses against Dsg3 that may serve as a target to modulate the production of pathogenic autoantibodies. Healthy carriers of major histocompatibility complex class II alleles identical or similar to those that are highly prevalent in pemphigus vulgaris, namely DRbeta1*0402 and DRbeta1*1401, also mount T cell responses against Dsg3. We thus wanted to determine whether these prevalent major histocompatibility complex class II alleles restricted Dsg3 specific T cell responses. A CD4+ T cell line from the DRbeta1*0402+ patient PV9 was stimulated by Dsg3 with DRbeta1*0402+ L cells as antigen-presenting cells. A CD4+ T cell line and six CD4+ T cell clones from the DR11/14+ patient PV8, and six CD4+ T cell clones from the DR11+ healthy donor C6, required DR11/ DQbeta1*0301+ peripheral blood mononuclear cells but not DR11+ L cells as antigen-presenting cells and were strongly inhibited by anti-DQ antibodies, indicating that they were restricted by HLA-DQbeta1*0301. A CD4+ T cell line and three T cell clones from the DR11+ healthy donor C11 were differentially stimulated by Dsg3 with L cells expressing one of several DR11 alleles. T cell recognition of Dsg3 was thus not only restricted by the pemphigus vulgaris associated DRbeta1*0402 allele, but also by several DR11 alleles, some of which are highly homologous to DRbeta1*0402, and by HLA-DQbeta1*0301.

HLA haplotypes and class II molecular alleles in Sardinian and Italian patients with pemphigus vulgaris

HLA class II antigens and DRB1, DQA1, DQB1 alleles were studied in 16 Italian and in 16 Sardinian patients with pemphigus vulgaris (PV). In the last group the complete HLA A-DQ haplotypes, including the complotypes, were defined by family studies. As in other populations, two PV susceptibility haplotypes were found: HLA-DRB1*0402, DQA1*0301, DQB1*0302 and HLA-DRB1*1401, DQA1*0104, DQB1*0503. The first haplotype was largely prevalent in the Sardinian patients and was a part of the extended haplotype HLA-A2, Cw4, B35, S31, DR4, DQ8. The strength of the allele associations to PV is in agreement with the view that the main PV susceptibility genes are the DRB1*0402 and DQB1*0503 alleles. A genetic resistance to PV seems to be conferred by the HLA-DR3, DQ2 haplotype in the Sardinian population.

HLA-DQA1, -DQB1 and -DRB1 genotyping in Japanese pemphigus vulgaris patients by the PCR-RFLP method

We performed HLA-DQA1, -DQB1 and -DRB1 genotyping using the PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method for 32 Japanese pemphigus vulgaris (PV) patients. There was a significant association of either DQB1*0503 or DRB1*1405 with PV, and a negative association of either DQA1*0103 or DQB1*0601 with PV was found. Since the DQB1*0503+ patients had various DR14-related alleles, we concluded that the association with DQB1 is primary and that the association with DRB1 is simply due to linkage disequilibrium between the DQ and DR genes. These results may indicate that specific HLA class II antigens confer the susceptibility to PV among Japanese.

Unique intronic variations of HLA-DQ beta gene in early-onset periodontitis

Human leukocyte antigen (HLA) class II beta chain plays an important role in the recognition of foreign antigens in immune reactions. Different forms of immune reaction may be concerned with initiation and progression of infectious diseases such as periodontitis. In this study we examined the frequency of HLA class II serotype and the variation of HLA class II beta gene in periodontitis patients. HLA serotypic frequencies in 70 Japanese patients with periodontitis and 26 individuals with periodontal health were examined. No HLA serotype specific to any type of periodontitis was observed. In order to detect differences among some HLA serotypes, restriction fragment length polymorphism (RFLP) analysis was undertaken with cDNA probes for HLA-DR beta and HLA-DQ beta genes in 20 subjects (15 patients and 5 healthy individuals). Atypical BamHI and EcoRI restriction sites were found in the HLA-DQ beta gene from 3 patients with early-onset periodontitis. In addition to these 20 subjects, an additional 80 subjects (40 patients and 40 healthy individuals) were screened for the atypical BamHI restriction site using the polymerase chain reaction method. It was detected in 7 patients with early-onset periodontitis, 1 patient with adult periodontitis, and 3 healthy subjects. No clinical differences except age were found between patients with this gene variation and other patients. Interestingly, all 3 healthy subjects with this gene variation were from subjects whose family members developed early-onset periodontitis with the gene variation. Atypical BamHI and EcoRI restriction sites and 41-nt repeated sequence were found in the intron before the third exon of HLA-DQB gene. These results suggest that these intronic gene variations may be useful as gene markers for a subpopulation of early-onset periodontitis and might affect immune reactions such as antigen recognition.