Familial pemphigus vulgaris

Epidemiological and clinical study of cases of endemic pemphigus foliaceus and pemphigus vulgaris in a reference center in the state of Minas Gerais, Brazil

BACKGROUND

Pemphigus constitutes a group of autoimmune bullous diseases. A reduction in the incidence of endemic pemphigus foliaceus and an increase in pemphigus vulgaris has been described, but there are no studies in Minas Gerais that address the subject.

OBJECTIVE

To describe the epidemiological and clinical profile of patients with pemphigus treated at the Dermatology Service of a public University Hospital in the state of Minas Gerais, Brazil.

METHODS

An observational, descriptive, and cross-sectional study was carried out of cases of endemic pemphigus foliaceus and pemphigus vulgaris, for a period of six months. A questionnaire was filled out with epidemiological and clinical data on the disease.

RESULTS

A total of 122 patients were included in the study, 64 with endemic pemphigus foliaceus and 58 with pemphigus vulgaris. When comparing patients with endemic pemphigus foliaceus and those with pemphigus vulgaris, a statistical difference was observed between the median age of initial disease manifestation (p = 0.001), patient occupation (p = 0.010), area of residence (p = 0.000), forests (p = 0.000) and rivers/streams close to the dwelling (p = 0.001) and the number of systemic medications required to control the disease (p = 0.002). When comparing patients with endemic pemphigus foliaceus to those evaluated in a study carried out at the same service in 2008, there was a statistical difference in the area of residence (p = 0.030).

STUDY LIMITATIONS

The assessed population comes from a tertiary care service that is not a reference for the entire state.

CONCLUSIONS

Patients with endemic pemphigus foliaceus and pemphigus vulgaris maintain statistically significant differences regarding their main variables in the literature, such as age and area of residence. Historically, there has been a reduction in cases of endemic pemphigus foliaceus and an increase in cases of pemphigus vulgaris in this population.

Role of Human Leukocyte Antigen Class II in Antibody-Mediated Skin Disorders

HLA class II molecules are key factors determining susceptibility to autoimmune disorders, and their role in immune-mediated skin conditions such as psoriasis has been extensively investigated. However, there is currently little understanding of their role in antibody-mediated skin diseases such as autoimmune blistering disorders. We researched the available literature using PubMed to narratively review the current knowledge on HLA associations in antibody-mediated blistering skin pathologies. Our results summarized the risk alleles that are identified in the literature, together with certain known protective alleles: in the pemphigus group, alleles HLA-DQB1*0503 and HLA-DRB1*0402 are most commonly associated with disease; in the pemphigoid group, the most studied allele is HLA-DQB1*0301; in epidermolysis bullosa acquisita, few genetic studies are available; in dermatitis herpetiformis, the association with haplotypes HLA-DQ2 and HLA-DQ8 is strongly established; finally, in linear IgA bullous disease, specific HLA alleles may be responsible for pediatric presentations. Our current pathogenic understanding of this group of disorders assigns a key role to predisposing HLA class II alleles that are able to bind disease autoantigens and therefore stimulate antigen-specific autoreactive T cells. The latter engage B lymphocytes that will produce pathogenic autoantibodies. The distribution of HLA alleles and their disease associations are variable across demographics, and an in-depth pathogenetic understanding is needed to support associations between HLA alleles and disease phenotypes. Additionally, in a personalized medicine approach, the identification of HLA alleles associated with the risk of disease may become clinically relevant in identifying susceptible subjects that should avoid exposure to known triggers, such as medication, when possible.

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.

Familial Pemphigus Vulgaris Occured in a Father and Son as the First Confirmed Cases

Pemphigus vulgaris (PV) is a chronic autoimmune bullous disease of the skin and mucous membranes. Although there is some evidence pointing towards a genetic predisposition by some human leukocyte antigen (HLA) genes, familial occurrence of PV is very rare. Most of the familial PV cases so far reported have been in mother and daughter and in siblings. PV in father and son, as presented here, has not been reported in the literature before, except an unconfirmed report. The diagnosis of PV was established by histologic, cytologic studies and enzyme linked immunosorbent assay (ELISA) in Case 1 and by ELISA and BIOCHIP indirect immunofluorescence test in Case 2. The son was responsive to moderate doses of methylprednisolone, with the treatment continuing with tapered doses. The father was in a subclinic condition; consequently, only close follow-up was recommended. HLA typing studies revealed identical HLA alleles of HLA-DR4 (DRB1^⁎04) and HLA-DQB1^⁎03 in both of our cases; this had been found to be associated with PV in prior studies. Familial occurrences of PV and related HLA genes indicate the importance of genetic predisposition. The first occurrence of confirmed familial PV in father and son is reported here.

Simultaneous Onset of Pemphigus Vulgaris in Two Turkish Siblings

The etiology of pemphigus vulgaris is still unknown. Reported familial cases are indicators of a genetic aspect of the disease. We report a brother and sister with simultaneous onset of pemphigus vulgaris. The class II antigens, HLA DRB1*04 and DQB1*03 were detected in both patients. The oral mucosa was affected in one them. Elevation of transaminase levels due to azathioprine therapy was observed in these two cases.

The genetics of pemphigus

Pemphigus vulgaris (PV) is an autoimmune blistering disorder with a complex etiology involving an interplay of genetic as well as environmental factors, most of which remain unknown. Despite the identification of several human leukocyte antigen (HLA) alleles as risk factors for disease, no other non-HLA genes have clearly been implicated in disease susceptibility. Newer candidate gene and whole-genome approaches are needed to illuminate the full palate of genetic risk elements in PV. Based on this information, genetic-based tools can be expected to provide a scientific rationale for future clinical decision-making by physicians and facilitate an era of personalized medicine.

Immunogenetics of pemphigus: An update

Pemphigus are rare but informative models of organ-specific autoimmune diseases, resulting from the interplay of environmental, genetic and stochastic factors. There are many arguments to consider that pemphigus have a genetic basis involving, as many other autoimmune diseases, several different genes with additive or synergistic effects. So far, the unique strategy used to identify the contributive loci has been direct analysis of candidate genes through conventional case-control association studies. The major histocompatibility complex in particular the class II locus was demonstrated to be associated with pemphigus with a high rate of replicability. The progresses in the understanding of pemphigus physiopathology and the development of new molecular tools offer new perspectives to unveiled the genetic basis of this group of autoimmune blistering diseases, as shown by recent studies of candidate genes expressed at different levels of the autoimmune process.

Pemphigus: Analysis of 1209 cases

BACKGROUND

Pemphigus is a rare and chronic life-threatening disease. The clinical picture varies in reports from different regions of the world.

OBJECTIVE

To define the clinical forms of pemphigus in a large cohort of patients.

METHODS

Prospective analysis of 1209 patients diagnosed and followed at the Pemphigus Research Unit, Tehran University for Medical Sciences, from 1984 to 2003.

RESULTS

The mean age at onset was 42 years with a female to male ratio of 1.5/1. The most frequent form was pemphigus vulgaris. In pemphigus vulgaris, patients' mucous membrane involvement alone was observed in 18%, skin involvement alone in 12%, and both in 70%. Pemphigus foliaceus was observed in 7% of the patients. Most complications were iatrogenic.

CONCLUSION

In Iran, pemphigus vulgaris is the most frequent form of pemphigus. Females are more prone to the disease. The incidence of pemphigus in Tehran is approximately 1.6 per 100,000/year, and in Iran 1.0 per 100,000/year. The age of onset was lower than classically reported. Death occurred in 6.2% of the patients. In pemphigus vulgaris, the mucosal and skin form together had a worse prognosis than the other clinical forms.

Genetic factors in pemphigus

Epidemiological studies performed in different ethnic populations and family studies, notably based on a partial phenotype of the autoimmune process, indicate that genetic factors are involved in the occurrence of pemphigus. However, the precise heritability remains uncertain in the absence of twin concordance rate studies. Among the different strategies available to identify genetic factors participating in autoimmune disease susceptibility, only population studies based on case-control design have been performed in pemphigus. These studies consistently showed that MHC locus, in particular HLA class II alleles, are associated with pemphigus vulgaris and pemphigus foliaceus. Other genes of the MHC locus may also participate in disease susceptibility as shown by studies using microsatellite markers across different regions of the MHC. It is likely that other non-MHC genes are involved in the pathogenesis of pemphigus. In particular, involvement of a polymorphic variant of desmoglein 1 gene was shown to be associated with pemphigus foliaceus and to interact in an epistatic manner with MHC class II genes to contribute to the autoimmune process. Other candidate genes to which a role can be assigned in the disease pathogenesis should be considered to design case-control or family-based association studies. Genome scan studies which require a large number of multiplex families to reach statistical power, should also be considered in the endemic form of pemphigus foliaceus because of the high number of familial cases.

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 distribution of pemphigus vulgaris-IgG subclasses and their reactivity with desmoglein 3 and 1 in pemphigus patients and their first-degree relatives

BACKGROUND

Pemphigus vulgaris (PV) autoantibodies (PV-IgG) have been found in 40-70% of sera of first-degree relatives of pemphigus patients.

OBJECTIVES

To determine the possible role of PV-IgG subclasses in the pathogenesis of the disease.

PATIENTS AND METHODS

Study groups comprised 25 PV patients, 55 unaffected family members and 56 sera of healthy individuals. Indirect immunofluorescence (IIF) staining and Western immunoblotting (WB) techniques were used to determine total PV-IgG and PV-IgG subclasses and their reactivity to desmoglein (Dsg) 1 and 3.

RESULTS

By IIF staining, circulating PV-IgG were found in 64% of the patients, in 15% of the relatives and in none of the controls (P < or = 0.001); by WB the results were 91%, 49% and 12%, respectively (P < or = 0.001). The distribution of PV-IgG subclasses 1-3 was similar among patients and their relatives. PV-IgG4 was found in 62% of the patients but in only one relative and was absent in the controls (P < or = 0.001). PV-IgG1, 2 and 4 were found to react mainly with Dsg3 and PV-IgG3 mainly with Dsg1 and 3.

CONCLUSIONS

These results support the concept of a genetic predisposition in pemphigus. The non-complement-fixing PV-IgG4 and at least one complement-fixing PV-IgG subclass appear to be involved in the pathogenesis of the disease. The absence of PV-IgG4 among relatives who were PV-IgG carriers seems to be linked to the fact that they do not develop pemphigus. The exact nature of this linkage is still unclear.

Circulating pemphigus IgG in families of patients with pemphigus: comparison of indirect immunofluorescence, direct immunofluorescence, and immunoblotting

BACKGROUND

Patients with pemphigus vulgaris (PV) are genetically linked to two alleles of the HLA subgroup, and circulating antibodies were found in first-degree relatives of these patients, thus showing genetic predisposition.

OBJECTIVE

Our purpose was to determine the occurrence of circulating true PV-IgG in patients' relatives.

METHODS

Circulating PV-IgG was determined in 21 first-degree relatives of 12 patients with PV by indirect immunofluorescence on monkey esophagus, carcinoma A431 cultures, and Western immunoblotting. Direct immunofluorescence was performed on skin biopsy specimens of 20 relatives.

RESULTS

Circulating PV-IgG was detected in 15 relatives (71%) by all methods tested. Good correlation was found between immunoblot reactivity and immunofluorescence. Of the 15 "positive" relatives, only five showed fixation of IgG to epidermal cells in vivo.

CONCLUSION

The permeability of the epidermis or epidermal cell reactivity in vivo probably controls the expression of disease in patients' relatives.

Unsuspected involvement of the female genitalia in pemphigus vulgaris

A 56-year-old woman had erosions due to pemphigus vulgaris in the inner thighs and perineum. The cutaneous lesions cleared following intramuscular gold therapy. However, because of complaints of dyspareunia, a colposcopic examination was performed and involvement of the cervix was demonstrated. The need for a vaginal examination in the monitoring of pemphigus vulgaris is emphasized.