HLA class II allele associations in Korean patients with pemphigus

A systematic review and meta-analysis of HLA class II associations in patients with IgG4 autoimmunity

Autoimmune diseases caused by pathogenic IgG4 subclass autoantibodies (IgG4-AID) include diseases like MuSK myasthenia gravis, pemphigus vulgaris or thrombotic thrombocytopenic purpura. Their etiology is still unknown. Polymorphisms in the human leukocyte antigen (HLA) gene locus, particularly in HLA-DRB1, are known genetic susceptibility factors for autoimmune diseases. We hypothesized a similar role for HLA polymorphisms in IgG4-AID and conducted a systematic review and meta-analysis with case-control studies on IgG4-AID based on MOOSE/ HuGENet guidelines. Genotype (G) and allele (A) frequencies of HLA-DQB1*05 (G: OR 3.8; 95% CI 2.44-5.9; p < 0.00001; A: OR 2.54; 95% CI 1.82-3.55; p < 0.00001) and HLA-DRB1*14 (G: OR 4.31; 95% CI 2.82-6.59; p < 0.00001; A: OR 4.78; 95% CI 3.52-6.49; p < 0.00001) and the HLA-DRB1*14-DQB1*05 haplotype (OR 6.3; 95% CI 3.28-12.09; p < 0.00001/OR 4.98; 95% CI 3.8-6.53; p < 0.00001) were increased while HLA-DRB1*13 (G: OR 0.48; 95% CI 0.34-0.68; p < 0.0001; A: OR 0.46; 95% CI 0.34-0.62; p < 0.00001) was decreased in IgG4-AID patients. In conclusion, the HLA-DQB1*05, HLA-DRB1*14 alleles and the HLA-DQB1*05-DRB1*14 haplotype could be genetic risk factors that predispose for the production of pathogenic IgG4 autoantibodies and the HLA-DRB1*13 allele may protect from IgG4 autoimmunity.

Allele frequency and the associations of HLA-DRB1 and HLA-DQB1 polymorphisms with pemphigus subtypes and disease severity

Pemphigus is a rare, devastating, bullous autoimmune disease that damages the skin and mucous membranes, and has high morbidity and mortality. Studies have shown associations of pemphigus vulgaris (PV) and pemphigus foliaceus (PF) with human leukocyte antigen (HLA) class II polymorphisms.This study examined the frequency of Major Histocompatibility Complex, Class II, DR Beta 1, a Protein Coding gene (HLA-DRB1) and Major Histocompatibility Complex, Class II, DQ Beta 1 (HLA-DQB1) alleles in Vietnamese PV and PF patients, and the association of these polymorphisms with pemphigus subtypes and disease severity.The study enrolled 31 unrelated Vietnamese who underwent HLA typing using Sanger sequencing.HLA-DRB1∗14:54 was the most frequent allele in both PV (20.5%) and PF (33.3%) patients. The percentage of HLA-DQB1∗03:02 was significantly higher in PF than PV patients, while the percentage of HLA-DQB1∗05:03 was approximately 10 times higher in PV patients. Pemphigus patients who have the HLA-DRB1∗04 alleles are more likely to have mild or moderate disease.The HLA-DRB1 and DQB1 alleles may influence susceptibility to pemphigus subtypes, with DQB1∗05:03 being specific for PV and DQB1∗03:02 for PF. Our findings suggest that the DRB1∗04 alleles are likely to be associated with mild and moderate disease.

Autoimmune Pemphigus: Latest Advances and Emerging Therapies

Pemphigus represents a group of rare and severe autoimmune intra-epidermal blistering diseases affecting the skin and mucous membranes. These painful and debilitating diseases are driven by the production of autoantibodies that are mainly directed against the desmosomal adhesion proteins, desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1). The search to define underlying triggers for anti-Dsg-antibody production has revealed genetic, environmental, and possible vaccine-driven factors, but our knowledge of the processes underlying disease initiation and pathology remains incomplete. Recent studies point to an important role of T cells in supporting auto-antibody production; yet the involvement of the myeloid compartment remains unexplored. Clinical management of pemphigus is beginning to move away from broad-spectrum immunosuppression and towards B-cell-targeted therapies, which reduce many patients’ symptoms but can have significant side effects. Here, we review the latest developments in our understanding of the predisposing factors/conditions of pemphigus, the underlying pathogenic mechanisms, and new and emerging therapies to treat these devastating diseases.

Autoantibody-Specific Signalling in Pemphigus

Pemphigus is a severe autoimmune disease impairing barrier functions of epidermis and mucosa. Autoantibodies primarily target the desmosomal adhesion molecules desmoglein (Dsg) 1 and Dsg 3 and induce loss of desmosomal adhesion. Strikingly, autoantibody profiles in pemphigus correlate with clinical phenotypes. Mucosal-dominant pemphigus vulgaris (PV) is characterised by autoantibodies (PV-IgG) against Dsg3 whereas epidermal blistering in PV and pemphigus foliaceus (PF) is associated with autoantibodies against Dsg1. Therapy in pemphigus is evolving towards specific suppression of autoantibody formation and autoantibody depletion. Nevertheless, during the acute phase and relapses of the disease additional treatment options to stabilise desmosomes and thereby rescue keratinocyte adhesion would be beneficial. Therefore, the mechanisms by which autoantibodies interfere with adhesion of desmosomes need to be characterised in detail. Besides direct inhibition of Dsg adhesion, autoantibodies engage signalling pathways interfering with different steps of desmosome turn-over. With this respect, recent data indicate that autoantibodies induce separate signalling responses in keratinocytes via specific signalling complexes organised by Dsg1 and Dsg3 which transfer the signal of autoantibody binding into the cell. This hypothesis may also explain the different clinical pemphigus phenotypes.

Autoreactive T cells in pemphigus: perpetrator and target

Pemphigus vulgaris (PV) is an autoimmune blistering disease, in which autoantibodies against epidermal cadherins, such as desmoglein (Dsg)1 and Dsg3, lead to the development of blisters and erosions on the skin and mucous membranes. Autoreactive CD4+ T cells are essential for the induction and perpetuation of the disease by interaction with B cells producing autoantibodies. PV has a strong genetic association with certain human leucocyte antigen (HLA) alleles with HLA-DRB1*04:02 and LA-DQB1*05:03 being the most prevalent in patients. Recently, genome-wide association studies have provided a new approach to identify single nucleotide polymorphisms, alongside the known association with HLA alleles. Loss of tolerance against Dsgs and other autoantigens is a critical event in the pathogenesis of PV. Epitope spreading contributes to the progression of PV, leading to an extension of the Dsg-specific autoimmune response to other molecular epitopes of autoantigens, such as desmocollins or muscarinic receptors. Alterations in CD4+CD25+ FoxP3+ regulatory T cells are thought to contribute to the development of PV representing a suitable target for therapeutic interventions. Several CD4+ T-cell subsets and cytokines are involved in the pathogenesis of PV, while Th2 cells are the extensively studied population. Recently, other T cell subsets like T follicular helper cells and Th17 have gained attention as new potential players in PV pathogenesis. The involvement of local autoantibody production in the lesional skin of PV patients in tertiary lymphoid organs is currently discussed but not yet clarified. In this study, we reviewed the current knowledge about the development, characteristics and function of autoreactive T cells in pemphigus and present current new T cell-targeted therapeutic approaches.

Sporadic pemphigus foliaceus and class II human leucocyte antigen allele associations in the white British and Indo-Asian populations in the UK

BACKGROUND

Pemphigus foliaceus (PF) has both genetic and environmental susceptibility factors. Current data on human leucocyte antigen (HLA) in patients with sporadic PF are limited.

AIM

To better define the distribution of HLA alleles in patients with PF in the UK.

METHODS

We recruited 36 patients [26 of white British (WB) descent, 10 of Indo-Asian (IA) descent] with PF who were living in the UK and 159 ethnically matched normal controls, and analysed their class II HLA DRB1 and DQB1 allele distribution.

RESULTS

There was an increased frequency of DRB1*1404 in association with DQB1*0503 in IA patients with PF. The DRB1*04 allele group as a whole had an increased frequency (P < 0.001) in the WB patient group compared with controls. The alleles contributing to this significance were DRB1*0401 (P = 0.03) and DRB1*0404 (P < 0.01).

CONCLUSION

This is the largest HLA association study in sporadic PF from the UK to date. There appears to be a difference in PF susceptibility alleles between WB and IA patients, highlighting the importance of racial variation in genetic susceptibility to disease development.

The Genetics of Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease caused by auto-antibodies (auto-Abs) directed against epithelial desmosomal components and leading to disruption of cell-cell adhesion. The exact mechanisms underlying the disease pathogenesis remain unknown and treatment is still based on immunosuppressive drugs, such as corticosteroids, which are associated with potentially significant side effects. Ethnic susceptibility, familial occurrence, and autoimmune comorbidity, suggest a genetic component to the pathogenesis of the disease, which, if discovered, could advance our understanding of PV pathogenesis and thereby point to novel therapeutic targets for this life-threatening disorder. In this article, we review the evidence for a genetic basis of PV, summarize the different approaches used to investigate susceptibility traits for the disease and describe past and recent discoveries regarding genes associated with PV, most of which belong to the human leukocyte antigen (HLA) locus with limited data regarding association of non-HLA genes with the disease.

Association between HLA-DQB1 polymorphisms and pemphigus vulgaris: A meta-analysis

OBJECTIVE

This study was performed to systematically summarize the results on the association of HLA-DQB1 polymorphisms with pemphigus vulgaris (PV) and other related factors.

METHODS

A comprehensive literature search of PubMed, The Cochrane Library, Embase, and Google Scholar database was conducted to identify relevant articles in English, with the last report up to November 1, 2016. Heterogeneity test was performed, and publication bias was evaluated. Stata software 12.0 was used to perform the meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CI) were used to describe the correlation by random-effects model.

RESULTS

18 studies were obtained after searching databases: 10 studies were about Caucasian, and 8 articles were about non-Caucasian. Meta-analysis revealed that the allele and phenotype frequencies of DQB1*05 were markedly higher in PV patients than in controls [P < 0.001, OR: 2.640, 95%CI: 1.570-4.441; P = 0.030, OR 3.688, 95%CI: 1.138-11.946]. In addition, DQB1*03 was significantly increased at the allele level [P < 0.001, OR: 2.080, 95%CI: 1.507-2.869], and DQB1*02 was significantly decreased in PV at the allele and phenotype levels [P = 0.002, OR: 0.450, 95%CI: 0.289-0.702; P = 0.001, OR: 0.293, 95%CI: 0.146-0.587]. When based on each subtype of HLA-DQB1, DQB1*05:03 and DQB1*03:02 may play susceptibility roles in PV, and DQB1*03:03, DQB1*05:01 and DQB1*06:01 are negatively associated with PV.

CONCLUSION

In summary, our study suggests that alleles from the groups DQB1*05 and DQB1*03, concretely DQB1*05:03 and DQB1*03:02, respectively, may be the susceptibility factors for PV at allele and phenotype levels, whereas DQB1*05:01, DQB1*02, DQB1*06:01, and DQB1*03:03 are negatively associated with PV.

Association between HLA-DRB1 polymorphisms and pemphigus vulgaris: a meta-analysis

Summary

Background Several studies have reported that HLA-DRB1 may be correlated with pemphigus vulgaris (PV), but most have been based on small samples and the results remain inconsistent and unclear.

Objectives To investigate the correlation between DRB1 and PV by a meta-analysis of case–control/nonfamily studies.

Methods PubMed, Wiley Online Library, ScienceDirect, Google Scholar, Cochrane Library, Chinese National Knowledge Infrastructure and Wanfang databases were searched for studies including: (i) ‘pemphigus’; and (ii) ‘human leukocyte antigen’, ‘HLA’, ‘major histocompatibility complex’, ‘MHC’ or ‘DRB1’. Eighteen selected studies were used in meta-analyses to evaluate DRB1 alleles and phenotypes by calculating the respective odds ratios (ORs) and 95% confidence intervals (CIs). Stratified meta-analyses and meta-regression analysis were also conducted.

Results The frequencies of three genotypes (allele and phenotype, respectively) were significantly increased in PV: DRB1*04 [P-value for comparability (Pc) < 0·00001, OR 3·61, 95% CI 2·28–5·71; Pc = 0·0002, OR 4·14, 95% CI 1·98–8·65], DRB1*08 (Pc = 0·03, OR 2·25, 95% CI 1·07–4·70; Pc = 0·0003, OR 2·46, 95% CI 1·51–4·01) and DRB1*14 (Pc < 0·00001, OR 6·47, 95% CI 4·52–9·26; Pc < 0·00001, OR 9·68, 95% CI 4·47–20·98). Three others (allele and phenotype, respectively) were significantly decreased in PV: DRB1*03 (Pc < 0·00001, OR 0·28, 95% CI 0·19–0·41; Pc = 0·0001, OR 0·25, 95% CI 0·12–0·51), DRB1*07 (Pc = 0·004, OR 0·45, 95% CI 0·26–0·78; Pc = 0·0002, OR 0·27, 95% CI 0·14–0·54) and DRB1*15 (Pc = 0·001, OR 0·35, 95% CI 0·18–0·66; Pc = 0·002, OR 0·32, 95% CI 0·16–0·65). Ethnicity partially explained the heterogeneity of DRB1*07, DRB1*08 and DRB1*14 phenotypes.

Conclusions Our findings suggest that DRB1*04, DRB1*08 and DRB1*14 are statistically significant susceptibility factors for PV. Conversely, DRB1*03, DRB1*07 and DRB1*15 may be negatively associated with PV. Specific HLA-DRB1 types may influence the susceptibility or resistance to PV, which needs further investigations.

Association of human leukocyte antigen class II alleles with pemphigus vulgaris in a Turkish population

Pemphigus vulgaris (PV) is a severe autoimmune blistering skin disorder that is strongly associated with major histocompatibility complex class II alleles. Human leukocyte antigen (HLA) subtypes vary with racial/ethnic backgrounds. The purpose of this study was to determine the association of HLA class II alleles and haplotypes with PV in Turkish patients. Twenty-five patients with PV and 113 healthy transplant donors were genotyped for HLA class II alleles. HLA DNA typing was performed by the polymerase chain reaction/sequence specific primer method. The frequency of HLA DRB1*04 allele was 68.00% in patients compared to 30.97% in controls (P = 0.0012) and the frequency of HLA DRB1*14 allele was 32.00% in the patient group compared to 8.85% in the control group (P = 0.0054). Also, the frequency of HLA DRB1*04/DQB1*03 and HLA DRB1*14/DQB1*05 haplotypes in PV patients was significantly higher than controls (32.0% vs 6.2%, chi(2) = 28.142, P < 0.001; and 16% vs 2.7%, chi(2) = 15.143, P = 0.001, respectively). A preventive allele or haplotype for the manifestation of PV has not been identified in this study. Our findings suggest that HLA DRB1*04 and DRB1*14 alleles, and HLA DRB1*04/DQB1*03 and HLA DRB1*14/DQB1*05 haplotypes are genetic markers for general susceptibility to PV in the Turkish population.

Prédisposition aux infections des malades ayant un pemphigus

INTRODUCTION

The relation between pemphigus and infection is complex. The aim of this work was to determine the frequency and impact of infection as well as the factors associated with it among our patients with pemphigus.

METHODS

This retrospective case series examined records of patients with pemphigus admitted to the dermatology unit of Ibn Sina University Hospital of Rabat between 1989 and 2004. We compared the patients with and without infections as well as the patients with and without severe bacterial infections according to patient profile and outcome. The principal outcome measure was death and the secondary measure, duration of hospitalization.

RESULTS

Of the 141 patients with pemphigus included in our study, 68% developed an infection. Infections were bacterial in 52% of cases, fungal in 50%, herpetic in 19% and parasitic in 1.5%. They were associated with diabetes mellitus and immunosuppressive drugs. Severe bacterial infection was frequent in patients with diabetes and rare in those treated with corticosteroids or with pemphigus foliaceous. Death occurred significantly more often among infected subjects (p=0.01), especially those with severe bacterial infections (p<0.001). Hospitalization was slightly longer among patients with infections (p=0.01) but shorter in cases of severe bacterial infections (p=0.004).

DISCUSSION

Our study confirms the predisposition to all types of infection among patients with pemphigus, as well as the undeniable role its treatment plays in promoting infection. Severe bacterial infections were most often contracted before hospitalization. The literature reports a wide variety of infections, with pemphigus-herpes documented most often. Prevention and management require hygienic measures as well as early diagnosis and treatment of pemphigus and infections. Preventive treatment may be considered, but studies are needed to define the patients who might benefit from it.

HLA-DRB1*0402 haplotypes without DQB1*0302 in Venezuelan patients with pemphigus vulgaris

The two basic forms of autoimmune intraepidermal blistering diseases, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), affect different layers of the skin, have different symptoms and target different antigens. We have defined human leukocyte antigen (HLA)-DRB1-DQB1 alleles and haplotypes in a case-control study of 66 non-Jewish patients attending a public reference Hospital over the past 10 years. The control group consisted of 101 matched individuals tested also by medium to high-resolution polymerase chain reaction-sequence-specific oligonucleotide with primers and probes from the 12th and 13th International Histocompatibility Workshop. Patients and controls were descendants of three-generation individuals born in the country. Among the patients, 49 had PV, 50% showed predominantly mucosal involvement, 50% showed predominantly the cutaneous clinical phenotype and 17 had PF. Statistically significant HLA-DR frequency differences between patients with PV and controls were found only for DRB1*0402 and DRB1*1401 [odds ratio (OR) = 27.22, confidence interval (CI) 94.7-7.82, P= 1.1 x 10(-14) and OR = 46.56, CI 801.4-2.70 P= 7.5 x 10(-6), respectively]. Both alleles were also increased in the patients with PF compared with the controls (OR = 7.0, P= 0.038 and OR = 21.64, P= 0.009, respectively), but the significance of the difference did not resist Bonferroni correction. Haplotype analysis showed that DRB1*0402 was always present with DQB1*0302 and DRB1*1401 with DQB1*0503, but no independent effect of the DQB1*0302 in the former haplotype was evident. Our results support the hypothesis that the DRB1*0402 without DQB1*0302 is the most relevant HLA-DRB1 allele responsible for the pathogenesis of pemphigus in Venezuelan patients with PV and discard the DQB1*0302 influence observed in other populations.

Epidemiologic survey of pemphigus vulgaris with oral manifestations in northern Greece: retrospective study of 129 patients

OBJECTIVE

To evaluate the epidemiology of pemphigus vulgaris (PV) in a Greek population and to compare it with other countries.

MATERIALS AND METHODS

A retrospective study was conducted based on the records of 129 patients (41 males and 88 females) with PV who visited the Department of the Oral Medicine and Maxillofacial Pathology, Aristotle University of Thessaloniki, Greece and the State Hospital for Skin and Venereal Diseases of Thessaloniki, Greece, between 1985 and 2004. A group of 73 individuals was used as controls.

RESULTS

The average annual incidence was found to be eight patients per year. The male to female ratio was 1 : 2.25. The difference in the age of onset between the two genders was statistically significant in marginal levels (P = 0.05). In addition, 86.1% of the patients showed oral lesions only, 13.3% oral and skin lesions and 1.3% manifested oral, skin, and ocular lesions. Twenty-eight of the 88 females were in the premenopausal period-of-life. Additionally, 19 males were farmers who had daily contact with organophosphoric pesticides. Co-existing pathologic conditions were present in 75 of the 129 patients, and of these 75 patients six (8%) were diabetics, 15 (20%) presented with hypertension, two (2.6%) faced problems from their thyroid gland, and 10 (13.3%) of the patients complained of allergic reactions.

CONCLUSIONS

The results of this study demonstrated a relatively high incidence of PV in northern Greece compared with that in other countries. The disease most frequently occurred in the sixth decade-of-life and the majority of the patients manifested oral lesions. Further epidemiological studies are needed to elucidate whether this region is constituted from population groups with high susceptibility to PV.

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.