Common major histocompatibility complex class II markers in clinical variants of cicatricial pemphigoid

Association of HLA class II alleles and haplotypes with bullous and mucus membrane pemphigoid risk: A systematic review, a meta-analysis and a meta-regression

Although, several studies have assessed the association of HLA Class II and genes with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP), results were inconsistent and between-studies heterogeneity needs to be investigated. An electronic literature search for eligible studies among all papers published prior to May 31, 2024, was conducted through PubMed, EMBASE, Web of science and Scopus databases. Meta-analyses together with subgroup analyses and meta-regressions were performed for the three following HLA genes: DRB1, DQA1 and DQB1. Combined analyses revealed a significant increase in pemphigoid risk conferred by the following alleles: DQB1*0301, DRB1*11, DRB1*1101 subtype and DQA1*0505, all p-values <.001. However, there was a moderate to high level of between-studies heterogeneity. Subgroup analyses revealed that the risk conferred by the aforementioned alleles was significantly higher in case of dipeptidyl peptidase-4 inhibitors induced BP (DBP) comparatively to idiopathic BP and MMP. In addition, the risk conferred by the DQB1*0301 was significantly higher in MMP (OR [95% CI] = 5.25 [4.03-6.84]) than in BP (OR [95% CI] = 2.22 [1.87-2.65]), p = .007. Besides, the DRB1*1101-DQB1*0301 and DRB1*11-DQA1*05-DQB1*0301 haplotypes were significantly associated with an increased pemphigoid risk, both p-values <.001. Conversely, the DQA1*0201 allele was significantly associated with reduced pemphigoid risk (OR [95% CI] = 0.3 [0.17-0.52]), with no between-studies heterogeneity (I2 = 0%, p = .76). This meta-analysis demonstrated that the DRB1*1101, DQA1*0505 and DQB1*0301 were significantly associated with increased pemphigoid risk. These associations were found to be significantly stronger in case of DBP comparatively to idiopathic pemphigoid. The DQA1*0201 allele seems to play a protective role against pemphigoid. Registration: This review has been registered on PROSPERO: CRD42024552821, Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024552821.

[Immunopathogenesis of mucous membrane pemphigoid]

A detailed understanding of the immunopathogenesis of mucous membrane pemphigoid (MMP) is of particular importance in view of the mostly difficult diagnostics and treatment of this blistering autoimmune dermatosis. A still unknown disturbance of the body's own immune tolerance leads to the formation of autoreactive cells. As the disease progresses these produce autoantibodies which are directed against structural proteins in the basement membrane zone (BMZ). After they bind to the target antigen, complement factors are deposited along the BMZ and inflammatory cells invade the underlying tissue and produce the characteristic subepithelial blistering. This inflammatory response is associated with fibrosis and scarring in many affected tissues. Most phases of MMP pathogenesis are poorly understood; however, the last few years have shed more light on this processes. These advances are mostly the result of animal and cell culture models. Typical clinical and immunopathological characteristics of MMP, such as oral, conjunctival and skin lesions, are reflected, for example, in an antibody transfer-induced mouse model for anti-laminin 332 MMP in adult mice. Dapsone, as first-line treatment for MMP patients, significantly reduced the severity of these symptoms, and fibrosis in the skin and mucous membranes was also found histologically, which makes the model well-suited for testing new therapeutic approaches for MMP patients and might be of help for further elucidation of the immunopathogenesis of MMP.

Molecular Basis for Global Incidence of Pemphigoid Diseases and Differences in Phenotypes

Pemphigoid (Pg) diseases are a group of potentially fatal autoimmune mucocutaneous diseases. They have different clinical phenotypes, involving only the skin or multiple mucous membranes. They occur globally and frequently affect the elderly. The common marker among all variants is the presence of autoantibodies targeting the dermal-epidermal or mucosal-submucosal junctions, or basement membrane zone (BMZ). Four target antigens in the BMZ were studied. These included BPAG1, BPAG2 and subunits of α6 and β4 human integrins. Our objective was to find a molecular basis for the global incidence of Pg diseases and a mechanism that will explain the vast differences in clinical phenotypes and outcomes. All the variants of Pg that were analyzed had a statistically significant association with HLA-DQβ1*03:01 in ten countries on four continents. This explains the reason for global incidence. Prediction models discovered multiple peptides in each of the four antigens that serve as T cell epitopes. These T cell epitopes were shown to bind to HLA-DQβ1*03:01. In addition, structure modelling demonstrated the peptide-HLA complex bound to the T cell receptor. These autoreactive T cells would stimulate B cells to produce specific anti-BMZ autoantibodies. Anti-BMZ autoantibodies with different specificities will produce different phenotypes, which will account for involvement of different tissues and organs in different molecules. The contribution this study makes is that it provides a molecular basis of why a similar disease occurs in different racial groups. Furthermore, it provides the basis for the production of autoantibodies with different specificities, which resultantly produces different phenotypes.

Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a clinically and immunopathologically heterogenous disease with an incidence of about 2/million inhabitants/year in central Europe. Pemphigoid diseases are characterized by autoantibodies against structural proteins of the epidermis and/or surface-close epithelia. MMP has been defined as pemphigoid disease with predominant mucosal lesions. Most frequently, the oral cavity and the conjunctivae are affected. Lesions outside the mouth tend to heal with scarring leading to visual impairment and finally blindness, as well as, more rarely, impairment of breathing and food intake. Autoantibodies target BP180 (collagen type XVII), laminin 332, BP230 (nearly always in conjunction with other antigens), and type VII collagen in about 75%, 10-20%, 10-30%, and <5% of MMP patients, respectively. While the main autoantibody isotype is IgG, additional, and less frequently, exclusive IgA autoantibodies can be detected in the majority of patients. Assaying for anti-laminin 332 reactivity is pivotal, since in about a quarter of patients with anti-laminin 332 MMP, a malignancy, mainly solid cancers, is associated. The pathophysiology of MMP is yet incompletely understood. A recent mouse model of anti-laminin 332 MMP replicating characteristic clinical and immunopathological findings of the human disease may be helpful to close this knowledge gap. Diagnosis is established by the clinical picture with predominant mucosal lesions and visualization of tissue-bound anti-basement membrane zone antibodies by direct immunofluorescence microscopy. In recent S3 guidelines initiated by the European Academy of Dermatology and Venereology, the clinical spectrum and diagnostic strategies are detailed. In addition, treatment regimens for different clinical situations including patients with exclusive oral or ocular involvement are outlined. Future studies are needed to better understand the clinal complexity and associations as well as to establish widely available diagnostic assays and evidence-based therapeutic strategies.

Incidence, prevalence, and demographic characteristics of ocular cicatricial pemphigoid in Colombia: data from the National Health Registry 2009-2019

AIM

To provide an epidemiological characterization of ocular cicatricial pemphigoid (OCP) in Colombia.

METHODS

We conducted a cross-sectional study using SISPRO. We applied the specific code of the International Classification of Diseases for Ocular Pemphigoid, from 2009-2019 to estimate prevalence, incidence, and the demographic status of the disease in Colombia.

RESULTS

The estimated average prevalence was 0.22 per 1 000 000 inhabitants, and the estimated average incidence was 0.24 per 1 000 000 inhabitants. With a female predominance of 62.5%, and a male/female ratio of 1:1.6. The group of patients diagnosed with the disease after the age of 80 presented the highest prevalence. The departments with the highest prevalence were Antioquia, Bogotá, and Santander.

CONCLUSION

There are important differences between worldwide and Colombian prevalence and incidence data, which may be related to genetic and epigenetic factors, and the possible underdiagnosis of the disease. According to the results, OCP is an extremely rare disease in Colombia. Nevertheless, it is important to encourage awareness of the disease due to its devastating consequences.

European guidelines (S3) on diagnosis and management of mucous membrane pemphigoid, initiated by the European Academy of Dermatology and Venereology - Part I

This guideline on mucous membrane pemphigoid (MMP) has been elaborated by the Task Force for Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology (EADV) with a contribution of physicians from all relevant disciplines and patient organizations. It is a S3 consensus-based guideline encompassing a systematic review of the literature until June 2019 in the MEDLINE and EMBASE databases. This first part covers methodology, the clinical definition of MMP, epidemiology, MMP subtypes, immunopathological characteristics, disease assessment and outcome scores. MMP describes a group of autoimmune skin and mucous membrane blistering diseases, characterized by a chronic course and by predominant involvement of the mucous membranes, such as the oral, ocular, nasal, nasopharyngeal, anogenital, laryngeal and oesophageal mucosa. MMP patients may present with mono- or multisite involvement. Patients' autoantibodies have been shown to be predominantly directed against BP180 (also called BPAG2, type XVII collagen), BP230, laminin 332 and type VII collagen, components of junctional adhesion complexes promoting epithelial stromal attachment in stratified epithelia. Various disease assessment scores are available, including the Mucous Membrane Pemphigoid Disease Area Index (MMPDAI), the Autoimmune Bullous Skin disorder Intensity Score (ABSIS), the 'Cicatrising Conjunctivitis Assessment Tool' and the Oral Disease Severity Score (ODSS). Patient-reported outcome measurements (PROMs), including DLQI, ABQOL and TABQOL, can be used for assessment of quality of life to evaluate the effectiveness of therapeutic interventions and monitor disease course.

A service evaluation of the diagnostic testing for mucous membrane pemphigoid in a UK oral medicine unit

BACKGROUND

Mucous membrane pemphigoid (MMP) is an uncommon bullous disease typically involving the oral cavity. The most commonly used laboratory test for the diagnosis of MMP is direct immunofluorescence (DIF) on fresh perilesional tissue; however, the sensitivity of this test may be hampered by technical difficulties. Immune-serological investigations can also be employed to render a diagnosis. The purpose of this paper was to present an evaluation of diagnostic testing for MMP within an Oral Medicine Unit in UK.

METHODS

A retrospective analysis of the medical records was undertaken for patients who had undergone biopsy and DIF testing from January 2016 to December 2018. Parameters analysed included clinical presentation, histopathological features, DIF, salt-split skin indirect immunofluorescence, ELISA anti-BP180 and BP 230 and HLA-DQB1*03:01 findings.

RESULTS

Thirty patients (23 females and 7 males, mean age 66.8 years old) were diagnosed with MMP through a combination of histopathology and serological testing. Sixteen patients (53%) were DIF positive, whereas in 14 (47%), MMP diagnosis was achieved using immune-serologic tests. HLA DQB1*03:01 status was undertaken in 15 DIF-positive and 12 DIF-negative patients, and HLA DQB1*03:01 was found in 73% and 58% of the cases, respectively.

CONCLUSIONS

This service evaluation has shown that when DIF is informative, it remains the gold standard technique for diagnosis of MMP. However, we have also highlighted the value of serological testing for increasing diagnostic yield for patients with suspected MMP and the potential for HLA DQB1*03:01 as an adjunctive test for the evaluation of MMP.

Role of immune cells in the ocular manifestations of pemphigoid diseases

Pemphigoid disease is classified according to the phenotypical location of the disease and the presence of different types of antibodies. The ocular distribution of pemphigoid mainly occurs in patients with bullous pemphigoid and mucous membrane pemphigoid. Several immune cells, including the cells of the innate immune system (neutrophils and γδ T cells) and the adaptive immune system (T and B cells), are involved in pemphigoid disease. The treatment of pemphigoid is still wide-ranging, and the most utilized treatment is the use of immunosuppressants and corticosteroids. In this scenario, it is absolutely important to screen the immune cells that are involved in this group of diseases and to determine if a targeted treatment approach is plausible. In conclusion, this review will identify some newer treatment possibilities for the whole spectrum of pemphigoid diseases.

[Mucous membrane pemphigoid]

Mucous membrane pemphigoid (MMP) is a pemphigoid disease defined by the presence of autoantibodies against the dermal-epidermal junction and predominant involvement of mucous membranes. Diagnosis is made by the clinical presentation and linear deposits of IgG and/or IgA and/or C3 at the dermal-epidermal junction by direct immunofluorescence microscopy of a perilesional biopsy. Circulating autoantibodies can be detected in most patients by indirect immunofluorescence microscopy on salt-split human skin as well as ELISA and immunoblotting with recombinant and cell-derived target antigens. For systemic treatment of MMP, corticosteroids, dapsone, mycophenolates, and azathioprine are applied. In severe cases and in cases with rapid disease progression cyclophosphamide, rituximab, high-dose intravenous immunoglobulins, and immunoadsorption are used. For the successful management of MMP patients, close cooperation with dentists, ophthalmologists, ENT specialists, gynecologists, and gastroenterologists is essential.

Ocular Mucous Membrane Pemphigoid: Current State of Pathophysiology, Diagnostics and Treatment

Mucous membrane pemphigoid (MMP) is a systemic cicatrizing autoimmune disease that primarily affects orificial mucous membranes, such as the conjunctiva, the nasal cavity, the oropharynx, and the genitalia. Ocular involvement occurs in about 70% of all MMP cases. Ocular MMP (OcMMP) also encompasses the conditions linear immunoglobulin A disease, mucosal dominated epidermolysis bullosa acquisita, and anti-laminin 332/anti-epiligrin/anti-laminin 5 pemphigoid. It is a complex clinical entity that may lead to ocular surface failure and result in inflammatory and infectious complications, as well as potentially devastating visual loss. Early diagnosis and appropriate treatment are of paramount importance and require a high level of expertise as this condition can be extremely challenging to diagnose and treat even for experienced clinicians. In this review we provide an up-to-date insight on the pathophysiology of OcMMP, with an emphasis on the current state of its diagnostics and therapeutics. Our the aim is to increase our understanding of OcMMP and highlight modern diagnostic and therapeutic options.

Mucous membranepemphigoid in two half-sisters. The potential roles of autoantibodies to β4 integrin subunits and HLA-DQβ1*0301

BACKGROUND

Mucous membrane pemphigoid (MMP) is a subepithelial autoimmune mucocutaneous disease. It most frequently affects the oral mucosa, followed by ocular and nasal mucosa, nasopharyngeal, anogenital, skin, laryngeal and esophageal mucosa.

MAIN OBSERVATION

Two half-sisters developed mucous membrane pemphigoid at approximately the same age. The older sister presented with primarily mucosal disease, while the younger had a more cutaneous disease. The histopathology demonstrated a subepithelial blister and direct immunofluorescence showed deposition of IgG and C3 at the basement membrane zone of perilesional tissues in both sisters. Antibodies to human β4 integrin were present in the sera of both patients and correlated with disease activity. Both sisters carried the same HLADQβ1* 0301 allele.

CONCLUSIONS

This is the first case of mucous membrane pemphigoid occurring in two half-sisters. Perhaps, it is the low incidence of mucous membrane pemphigoid that may account for the lack of reports on familial cases of the disease.

The molecular basis for the presence of two autoimmune diseases occurring simultaneously--preliminary observations based on computer analysis

Specific Human Leukocyte Antigen Class II (HLA II) molecules associated with pemphigus vulgaris (PV), mucous membraine pemphigoid (MMP), and mixed connective tissue disease (MCTD) may react with multiple T cell epitopes within desmoglein 3 (Dsg 3), bullous pemphigoid antigen 2 (BPAG 2), and 70 kDa polypeptide small nuclear ribonucleoproteins (snRNP70) in autoantibody production. We report a group of patients with simultaneous occurrences of PV with MCTD, and MMP with MCTD. In one patient group, we performed serological studies to show presence of antibodies to Dsg 3, Dsg 1, and snRNP70 simultaneously. In the second group, we performed serological studies to show presence of antibodies to BPAG 1, BPAG 2, β4 integrin, and snRNP70 simultaneously. In both groups, HLA II genes were analyzed and the observations were consistent with previously described associations with PV, MMP, and MCTD. It is possible that HLA-DQβ1*0301 allele, present in 10 of 17 patients and DRβ1*04 in some of the others, may have the ability to bind to several relevant T cell epitopes in the snRNP70 molecule. We have utilized a computer model to demonstrate that HLA II-restricted T cell epitopes present within the known autoantigens may be capable of eliciting an immune response. While other explanations and mechanisms exist, the authors suggest that epitope spreading may be one possible mechanism, amongst others, that may result in the simultaneous presence of two separate pathogenic autoantibodies.

Role of MHC Class II genes in the pathogenesis of pemphigoid

Pemphigoid (Pg) is an autoimmune subepidermal blistering disease that affects the elderly population. The phenotype can be Bullous Pemphigoid (BP), which primarily involves the skin, or Mucous Membrane Pemphigoid (MMP), which primarily involves mucus membranes. Ocular Cicatricial Pemphigoid (OCP) and Oral Pemphigoid (OP) are subsets of MMP. The known antigens in BP are Bullous Pemphigoid Antigen 1 (BPAG1, also known as BP230), Bullous Pemphigoid Antigen 2 (BPAG2, also known as BP180), and subunits of human integrins α6 and β4. The Human Leukocyte Antigen (HLA) allele HLA-DQβ1*0301 has been reported to be associated with enhanced susceptibility to all of these subsets. Sera of patients with the four subsets are characterized by the presence of anti-Basement Membrane Zone (anti-BMZ) antibodies. In this manuscript, we present a model in which relevant portions of the four different antigens involved in pemphigoid have potential sites that could be presented by an antigen presenting cell (APC) in conjunction with DQβ1*0301 to a T cell receptor to initiate the process that results in anti-BMZ antibody production. Thus, this model provides a hypothetical computer-based mechanism to explain how a single HLA allele can be associated with the production of antibodies to four different antigens that result in four different subsets of a disease with four different clinical profiles and prognoses.

Relationship between target antigens and major histocompatibility complex (MHC) class II genes in producing two pathogenic antibodies simultaneously

In this report,we present 15 patients with histological and immunopathologically proven pemphigus vulgaris (PV). After a mean of 80 months since the onset of disease, when evaluated serologically, they had antibodies typical of PV and pemphigoid (Pg). Similarly, 18 patients with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP) were diagnosed on the basis of histology and immunopathology.After a mean of 60 months since the onset of disease, when their sera were evaluated they were found to have Pg and PV autoantibodies. In both groups of patients the diseases were characterized by a chronic course, which included several relapses and recurrences and were non-responsive to conventional therapy. The major histocompatibility complex class II (MHC II) genes were studied in both groups of patients and phenotypes associated typically with them were observed. Hence, in 33 patients, two different pathogenic autoantibodies were detected simultaneously. The authors provide a computer model to show that each MHC II gene has relevant epitopes that recognize the antigens associated with both diseases. Using the databases in these computer models, the authors present the hypothesis that these two autoantibodies are produced simultaneously due to the phenomena of epitope spreading.

Oral mucous membrane pemphigoid in a 6-year-old boy: diagnosis, treatment and 4 years follow-up

BACKGROUND

Childhood oral pemphigoid is extremely rare and usually takes the form of desquamative gingivitis.

CASE REPORT

We describe a 6-year-old boy who presented with gingival bleeding, pain, eating difficulty, and peeling of the gums. Clinical examination revealed desquamative gingivitis with no extra-oral involvement. The diagnosis was established as oral pemphigoid based on the clinical, histological, and immunofluorescence findings. Symptoms resolved on treatment with occlusive topical corticosteroids. The patient was a carrier of the HLA-DQB(1)*0301 allele.

CONCLUSION

Mucous membrane pemphigoid should be considered in the differential diagnosis of chronic desquamative gingivitis in childhood. Occlusive therapy with topical fluocinonide may alleviate the symptoms.

Oral mucosal diseases: Mucous membrane pemphigoid

Subepithelial vesiculobullous conditions are chronic autoimmune disorders that arise from reactions directed against components of the hemidesmosomes or basement membrane zones (BMZ) of stratified squamous epithelium to which the term immune-mediated subepithelial blistering diseases (IMSEBD) has been given. Mucous membrane pemphigoid (MMP) is the most common, but variants do exist. Non-immune disorders that involve these epithelial components typically have a genetic basis--the main example being epidermolysis bullosa. All subepithelial vesiculobullous disorders present as blisters and erosions, and diagnosis must be confirmed by biopsy examination with immunostaining, sometimes supplemented by other investigations. No single treatment reliably controls all subepithelial vesiculobullous disorders; the immunological differences within IMSEBD may account for differences in responses to treatment. Currently, as well as improving oral hygiene, immunomodulatory treatment is used to control the oral lesions of MMP, but it is not known if its specific subsets reliably respond to different agents.

Treatment and relapse of autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a peculiar type of chronic pancreatitis whose pathogenesis involves autoimmune mechanisms. The steroid responsiveness has a significant impact on the diagnosis of AIP because patients with AIP and pancreatic cancer share many clinical features. This review focuses on the treatment and relapse of AIP. The goal of AIP treatment is remission of symptoms, serology, radiologic changes, or histology, which also applies to relapse. Although it is generally agreed that steroids should be offered to AIP patients with active disease, there is no standardized steroid regimen for AIP and no consensus on the dose and duration of steroid induction and tapering schedule, and optimal duration and dose of maintenance therapy. Obtaining a consensus on the optimal treatment regimen is very important to reducing the relapse rate. In this review, we discuss the treatment regimens used in many centers.

Substitution of aspartic acid at position 57 of the DQbeta1 affects relapse of autoimmune pancreatitis

BACKGROUND & AIMS

Although autoimmune pancreatitis (AIP) responds well to corticosteroid therapy, relapse during maintenance corticosteroid therapy or after the withdrawal of corticosteroid treatment is not uncommon. To date, the factors related to relapse of AIP have not been fully explored.

METHODS

To determine the clinical and genetic predictors relating to the relapse of AIP, we evaluated clinical factors, HLA polymorphisms, and the amino acid sequences in 40 patients with AIP.

RESULTS

At a median follow-up period of 40 months (range, 12-67 months), relapse developed in 13 of 40 patients with AIP (33%), in whom complete remission was achieved with oral corticosteroid therapy. Among demographics, clinical characteristics in the initial diagnosis of AIP, we could not find any clinical predictor for relapse of AIP; however, in amino acid sequence analysis for relapse of AIP, the substitution of aspartic acid to nonaspartic acid at residue 57 of DQbeta1 showed a significant association with relapse of AIP (nonrelapse group, 29.6%; relapse group, 100%; P = .00003; odds ratio, 3.38; 95% confidence interval, 1.9-6.0). There was a significant difference in the timing of relapse of AIP, according to density of the nonaspartic acid residue at DQbeta1 57 (nonaspartic acid homozygosity: mean +/- SD, 6.7 +/- 4.2 months; nonaspartic acid heterozygosity: mean +/- SD, 33 +/- 11 months; P < .001).

CONCLUSIONS

Substitution of aspartic acid to nonaspartic acid at DQbeta1 57 appears to represent a key genetic factor for relapse of AIP (ClinicalTrials.gov number, NCT00444444).

Bullous pemphigoid antigen II (BP180) and its soluble extracellular domains are major autoantigens in mucous membrane pemphigoid: the pathogenic relevance to HLA class II alleles and disease severity

BACKGROUND

Mucous membrane pemphigoid (MMP), a chronic autoimmune subepithelial blistering disease, is associated with circulating IgG and/or IgA autoantibodies against several basement membrane zone antigens. The heterogeneity of clinical presentation and diversity of target autoantigens have contributed to difficulties in characterizing this condition immunologically.

OBJECTIVES

To analyse serum autoantibody profile and HLA class II alleles in MMP patients and to correlate this with the clinical presentation of disease.

METHODS

Well-defined subgroups consisting of 124 patients with MMP were examined for IgG and IgA reactivity with immunoblotting using human epidermal, dermal and placental amnion proteins. The results were further analysed on the basis of detailed clinical (sites of involvement and disease severity) and immunopathological criteria (immunofluorescence study and HLA class II alleles).

RESULTS

Immunoblot assay revealed that the majority of MMP patients had IgG (93 of 124, 75%) and/or IgA autoantibodies (63 of 124, 51%) to BP180 (including its soluble ectodomains, 120-kDa LAD-1 and 97-kDa LABD97 antigens). Other antigens targeted predominantly by IgG autoantibodies included: BP230 in 34 (27%), beta4 integrin in 26 (21%), and laminin 5 in three (2%). All the BP230+ sera and 23 (88%) beta4 integrin+ sera also reacted with at least one of the BP180 antigens. Over 85% of patients with reactivity to beta4 integrin had ocular involvement. In most cases of MMP, more severe clinical features were associated with antibody reactivity to multiple basement membrane zone antigens, as well as reactivity to multiple BP180 component antigens. Dual BP180/LAD-1 reactivity with IgG and IgA was associated with a more severe phenotype. In addition, the subset-dependent autoantibody reactivity correlated well with specific HLA class II alleles, DQB1*0301, DRB1*04 and DRB1*11.

CONCLUSIONS

Our results confirmed that BP180 is a major autoantigen targeted by the sera of patients with MMP. The disease-prevalent HLA class II alleles and humoral autoimmune response against the particular subsets of antigenic epitope(s) within BP180 ectodomain may contribute to the clinicopathological significance and disease severity of MMP.

Number III Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a sub-epithelial vesiculobullous disorder. It is now quite evident that a number of sub-epithelial vesiculobullous disorders may produce similar clinical pictures, and also that a range of variants of MMP exist, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated sub-epithelial blistering diseases (IMSEBD) has therefore been used. Immunological differences may account for the significant differences in their clinical presentation and responses to therapy, but unfortunately data on this are few. The diagnosis and management of IMSEBD on clinical grounds alone is impossible and a full history, general, and oral examination, and biopsy with immunostaining are now invariably required, sometimes supplemented with other investigations. No single treatment regimen reliably controls all these disorders, and it is not known if the specific subsets of MMP will respond to different drugs. Currently, apart from improving oral hygiene, immunomodulatory-especially immunosuppressive-therapy is typically used to control oral lesions. The present paper reviews pemphigoid, describing the present understanding of this fascinating clinical phenotype, summarising the increasing number of subsets with sometimes-different natural histories and immunological features, and outlining current clinical practice.

Rapid effector function of circulating NC16A-specific T cells in individuals with mucous membrane pemphigoid

BACKGROUND

Mucous membrane pemphigoid (MMP) is a chronic blistering skin disease frequently associated with circulating autoantibodies directed to a number of antigens including the NC16A region of BP180. NC16A domain-specific T cells have been identified in the blood of individuals with bullous pemphigoid (BP), pemphigoid gestationis and linear IgA disease, but there are no data investigating the potential role for such T cells in the pathogenesis of MMP.

OBJECTIVES

To test the hypothesis that NC16A-specific T cells exist in the peripheral blood of individuals with MMP.

METHODS

We isolated peripheral blood mononuclear cells from 10 patients with MMP, 17 with BP and 10 healthy controls and examined the immunogenicity of overlapping peptides spanning the NC16A domain using interferon (IFN)-gamma enzyme-linked immunospot assay.

RESULTS

Significant IFN-gamma production was observed in response to the NC16A peptides in two of the patients with MMP and two of the patients with BP but in none of the normal controls. These data suggest that in a minority of individuals with MMP, NC16A domain-specific T cells circulate at sufficiently high frequency to be detectable directly ex vivo and to show rapid effector function.

CONCLUSIONS

Overall, these findings are the first to examine the potential role for antigen-specific autoreactive T cells in the pathogenesis of MMP, and confirm that in some individuals the NC16A domain may be an important target antigen.

Subepidermal blistering disorders: a clinical and histopathologic review

The subepidermal blistering disorders are comprised of a number of unrelated disorders with a diverse clinical presentation and pathogenic basis that share in common the presence of blister formation beneath the epidermis. Many of the disorders are both debilitating and potentially fatal. Timely and accurate diagnosis facilitates their appropriate management. The etiologic, clinical, and pathologic attributes as well as the treatment of these disorders including bullous pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis, linear IgA dermatosis, cicatricial pemphigold, herpes gestationis,and porphyria cutanea tarda are described.

TNF-alpha promoter single nucleotide polymorphisms are markers of human ancestry

We present a map of single nucleotide polymorphisms (SNPs) in the human tumor necrosis factor (TNF)-alpha promoter based upon exploratory sequencing of 333 human TNF-alpha gene promoters from individuals of distinct ancestral backgrounds. We detect 10 TNF-alpha promoter SNPs that occur with distinct frequencies in populations of different ancestry. Consistent with these findings, we show that two TNF-alpha SNPs, the -243 SNP and the -856 SNP, are the first SNP markers of a sub-Saharan African-derived extended haplotype and an Amerindian HLA haplotype, respectively. Comparisons of TNF-alpha promoter SNP allele frequencies can thus help elucidate variation of HLA haplotypes and their distribution among existing ethnic groups and shed light into the history of human populations.

HLA-DR and DQ polymorphisms in bullous pemphigoid from northern China

Bullous pemphigoid (BP) is an autoimmune disease mediated by autoantibodies against hemidesmosome components. This study used PCR-sequence-specific primers to genotype polymorphisms in HLA-DR and DQ in 25 BP patients and 57 normal controls from northern China. We found lower frequencies of DRB1*08 (DR8) and DRB1*08/DQB1*06 (DR8/DQ6) haplotypes in BP patients than in controls (4.08% vs. 15.19% and 1.54% vs. 13.82%, respectively; P < 0.05), suggesting a protective role for DR8 and DR8/DQ6 haplotypes in BP patients from northern China; there were no statistical differences among other alleles tested. This result is strikingly different from previous reports that DQB1*0301 is associated with BP in Caucasian patients and DRB1*1101, DQB1*0302, DRB1*04/DQA1*0301/DQB1*0302 and DRB1*1101/ DQA1*0505/DQB1*0302 with Japanese BP patients. Ethnic differences in the polymorphic composition of the HLA-DR and DQ genes may influence genetic susceptibility to BP.

HLA-DQB1 alleles in Italian patients with mucous membrane pemphigoid predominantly affecting the oral cavity

BACKGROUND

Mucous membrane pemphigoid (MMP) used to be considered as a single entity but it is now evident that a range of variants exists. Among them, pure ocular cicatricial pemphigoid (OCP) and pure oral pemphigoid (OP) appear to be very different subsets. Previous immunogenetics studies have found increased occurrence of the DQB1*0301 allele mainly in patients with OCP whereas in patients with OP the data are more open to doubt.

OBJECTIVES

To analyse HLA predisposition in a group of Italian patients with MMP predominantly affecting the oral cavity.

METHODS

We carried out high-resolution typing of HLA-DQB1 alleles in 28 patients with MMP predominantly affecting the oral cavity and in 97 geographically matched, healthy controls. All were Italian caucasians.

RESULTS

The frequency of HLA-DQB1*0301 was significantly increased in the MMP patients compared with the controls (96% vs. 48%; corrected P, Pc = 0.001; relative risk, RR = 28.73). A strong association with DQB1*0301 was also evident in patients with OP compared with the controls (95% vs. 48%; Pc = 0.01; RR = 20.21). There was no significant difference in DQB1*0301 frequency between patients with OP and with MMP not restricted to the oral cavity. Patients with MMP were more frequently homozygous for DQB1*0301 than the controls (43% vs. 8%; Pc < 0.001; RR = 8.34).

CONCLUSIONS

Our data suggest that Italian patients with MMP lesions predominantly affecting the oral cavity present the same genetic predisposition linked to HLA-DQB1*0301 previously reported mainly in patients with OCP.

Mucous membrane pemphigoid: HLA-DQB1*0301 is associated with all clinical sites of involvement and may be linked to antibasement membrane IgG production

BACKGROUND

Class I human leucocyte antigens (HLA) -A, -B, -Cw and class II HLA-DRB1, -DQB1 alleles were determined in 131 British Caucasian patients with mucous membrane pemphigoid (MMP) using serological and DNA-based methods.

OBJECTIVES

To analyse the class I and II alleles expressed in well-defined clinical and immunopathological subgroups of MMP, in order to establish whether specific alleles or haplotypes might in part explain disease susceptibility, clinical sites of involvement or disease severity.

METHODS

Subgroups of patients were analysed according to the following clinical criteria: age of onset, sex, sites of clinical involvement (oral, ocular, skin, nasal, genital, pharyngeal, oesophageal, laryngeal, perianal), disease severity and history of autoimmune disease. Subgroups were also analysed according to the following immunopathological criteria: autoantibody profile, the presence of circulating antibasement membrane IgG or IgA antibodies and the detection of target basement membrane zone (BMZ) antigens (BP230 and BP180) by IgG autoantibodies.

RESULTS

Class I HLA typing showed no significant disease or subgroup associations. Class II DRB1 typing showed a significantly increased allelic frequency in MMP vs. controls for DRB1*11 (RR = 2.08, Pc < 0.0000056). For DQB1, MMP vs. controls, there was a significantly increased allelic frequency for DQB1*0301 (Pc < 0.00000028) in both males and females; all clinical sites of involvement, with the exception of laryngeal, oesophageal and perianal sites and in patients with detectable circulating anti-BMZ IgG compared with those negative for IgG (P < 0.0096, Pc < 0.019). A positive trend was noted in patients with ocular involvement compared with no ocular involvement and in patients with a clinical score > or = 10 compared with < 10. We found no difference in DQB1*0301 allele frequency between subgroups with or without BP180 or BP230 target antigens. Haplotype frequencies showed an increase in DRB1*04, DQB1*0301 (Pc < 0.000066) and DRB1*11, DQB1*0301 (Pc < 0.000002) among patients compared with controls.

CONCLUSIONS

The DQB1*0301 allele confers a predisposition to all subgroups of MMP and may have a role in T-cell recognition of basement membrane antigens, resulting in the production of anti-BMZ IgG autoantibodies. The positive trend between increased allelic expression of DQB1*0301 in patients with ocular disease and in those with a higher clinical score, further suggests a role for this allele in disease severity.

A spontaneous canine model of mucous membrane (cicatricial) pemphigoid, an autoimmune blistering disease affecting mucosae and mucocutaneous junctions

Mucous membrane pemphigoid (MMP) is a rare autoimmune blistering dermatosis of humans that was previously known as cicatricial pemphigoid. It is characterized by vesicles, ulcers and scarring that affect predominantly mucosae and mucocutaneous junctions. Circulating autoantibodies recognize epitopes on basement membrane proteins such as collagen XVII or laminin-5/6. Herein, we describe the clinico-pathological and immunological characteristics of 17 dogs afflicted with a dermatosis homologous to MMP of humans. Patients exhibited vesicles and erosions predominantly on mucous membranes or mucocutaneous junctions of the mouth, nose, eyes, genitalia or anus. Histopathology revealed subepithelial vesicles with variable dermal inflammation. Direct immunofluorescence demonstrated IgG or complement at the dermoepithelial junction. Indirect immunofluorescence using salt-split epithelia permitted the detection of circulating basement membrane-specific IgG autoantibodies in 15 cases. In 11 patients, autoantibodies recognized the NC16A segment of collagen XVII, as determined by salt-split indirect immunofluorescence, immunoblotting using canine keratinocytes and ELISA with synthetic canine peptides. In one dog, autoantiodies bound to the dermal side of salt-split epithelia and recognized epitopes within the 30 kDa carboxy-terminal segment of human collagen XVII. Canine MMP, like its human counterpart, exhibits distinctive clinical signs and histopathological lesions, yet circulating autoantibodies target different antigenic epitopes. This spontaneous canine model of MMP could prove useful for studies on the pathogenesis or therapy of this human disease.

In vitro organ culture model for mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP), also known as cicatricial pemphigoid, is a rare vesiculobullous disease of mucosal tissues, which involves the oral, ocular, and other mucous membranes. We have studied a group of patients with histologically and immunopathologically proven pemphigoid disease involving predominantly the conjunctiva and oral mucosa in addition to other mucosae. The purpose of our study was to (i) demonstrate the specific binding of autoantibodies present in the sera of patients with MMP to normal human oral mucosa by indirect immunofluorescence (IIF) and (ii) to study the role of these autoantibodies in the pathogenesis of subepithelial blister formation using normal human buccal mucosa in organ culture. Serum and IgG fractions from MMP patients showed homogeneous smooth linear binding along the basement membrane zone (BMZ) of the normal buccal mucosa on IIF. Serum from pemphigus vulgaris patients showed intercellular or keratinocyte cell surface staining. BMZ separation developed at 48 h after incubation of normal human buccal mucosa in organ culture, with serum or IgG from patients with MMP but not after addition of normal human serum. Addition of pemphigus vulgaris serum to the in vitro culture of normal human buccal mucosa showed acantholysis. This preliminary report suggests that circulating autoantibodies may have an important role in the pathogenesis of MMP. This in vitro organ culture model will facilitate enhancing our understanding of various molecular events during the process of blister formation in MMP and in the study of other mucosal diseases.

Immunopathological diagnosis of cicatricial pemphigoid with desquamative gingivitis. A case report

Cicatricial pemphigoid (CP) is a chronic subepidermal bullous dermatosis which primarily involves the mucous membranes. The oral cavity and the eye are most frequently involved. Since extension of the lesion into the pharynx and esophagus causes sore throat and dysphagia and progressive ocular lesions may cause blindness, early and valid diagnosis is very important. Here we present a case of cicatricial pemphigoid with onset at age 45 in a patient who manifested severe periodontal disease and showed the lesion on the mucous membranes of the mouth (desquamative gingivitis), skin, and eyes. Since definite diagnosis is very important, we describe how we made a differential diagnosis from other diseases which also accompany desquamative gingivitis. We examined the clinical manifestations, blood test results, HLA-genotype, histopathologic findings of the affected tissue, and immunological findings in relation to autoimmunity. Since many of the CP cases are first referred to periodontists or dentists, we believe that the diagnostic strategy described in the present study will be quite informative for making rapid and definite diagnoses of similar cases.

Cicatricial pemphigoid

Cicatricial pemphigoid (CP) is a heterogeneous group of rare, chronic, subepithelial blistering disorders of the mucous membranes and, occasionally, the skin, which can have serious and rarely fatal consequences. The most common clinical features are desquamative gingivitis, oral erosions, and conjunctival fibrosis. Skin lesions occur less frequently and may present as widespread vesicles and bullae, as in bullous pemphigoid (BP). In some patients, the scarring can be a source of significant morbidity because it can result in odynophagia, strictures of the upper aerodigestive tract, or corneal opacities leading to eventual blindness. This article is a comprehensive review and discusses clinical, pathologic, and pathophysiologic aspects of this group of disorders collectively known as CP. (J Am Acad Dermatol 2000;43:571-91.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be familiar with the clinical spectrum of CP, the histopathologic and immunopathologic characteristics, the differential diagnosis, the treatment, and the natural history of the disease. Furthermore, this learning activity should facilitate early diagnosis of CP and should promote the idea that the involvement of other specialists, including ophthalmologists, otolaryngologists, gastroenterologists, and oral medicine specialists, as appropriate, will aid in providing these patients with the highest quality of care.

CTLA4 exon 1 dimorphism in bullous and cicatricial pemphigoid

The human cytotoxic T-lymphocyte antigen 4 (CTLA4) gene encodes proteins regulating the immune response. The polymorphism of this gene is associated with some autoimmune diseases. In this study, we analysed the distribution of the dimorphisms of exon 1 (+ 49 A/G) in bullous pemphigoid (BP) and cicatricial pemphigoid (CP), two types of autoimmune bullous skin diseases that occur in elderly people. The frequency of the exon 1 A-G genotype was marginally decreased in patients (36.4%; n = 55) compared with controls (52.8%, n = 53), but the results were not statistically significant (P = 0.09).

Polymorphisms of HLA-DR and -DQ genes in Japanese patients with bullous pemphigoid

Bullous pemphigoid (BP), an autoimmune skin disease of the elderly, is mediated by autoantibodies that bind to hemidesmosomes of epidermal basal cells. This study investigated BP-associated HLA-DR and -DQ genes among Japanese patients. We analyzed HLA-DR and -DQ genes among 23 Japanese BP patients based on the polymerase chain reaction-restriction fragment length polymorphism. Eighteen of these 23 patients (78%) carried at least one allele of HLA-DRB1*04 or DRB1*1101, with significant increases in HLA-DRB1*04 (*0403, *0406)/DQA1*0301/DQB1*0302 and DRB1*1101/DQA1*0505/DQB1*0302 haplotypes as well as the individual alleles DRB1*1101 and DQB1*0302 (corrected p < 0.05 for each comparison), when compared to control subjects. These data differ from the accepted DQB1*0301 (DQ7) association with the same disease among Caucasians. These findings indicate that different HLA class II haplotypes genetically influence susceptibility to BP among different ethnic groups. Our findings, together with previous reports on Caucasian patients with the pemphigoid group of bullous diseases, suggest that HLA-DRB1 molecules might participate in the regulation of autoimmune responses to BP antigens.

Intravenous immunoglobulin therapy for ocular cicatricial pemphigoid: a preliminary study

OBJECTIVE

To report the effects of intravenous immunoglobulin treatment of ten patients with progressive ocular cicatricial pemphigoid who did not respond to conventional immunomodulatory regimens.

DESIGN

Noncomparative, interventional case series.

PARTICIPANTS

Ten patients with biopsy-proven progressive cicatricial pemphigoid affecting the eyes who did not respond adequately to other local and systemic immunosuppressive treatment regimens.

INTERVENTION

Intravenous infusions of pooled human immunoglobulin, 2 to 3 g/kg body weight/cycle, divided over 3 days, and repeated every 2 to 6 weeks.

MAIN OUTCOME MEASURES

Reduction in conjunctival inflammation, prevention of progression of subepithelial conjunctival fibrosis, improvement in ocular symptoms (discomfort, photophobia), improved visual acuity, reduction in extraocular mucosal lesions.

RESULTS

Clinical deterioration was arrested and resolution of chronic conjunctivitis was documented in all ten patients. Maximum therapeutic effect was observed and maintained after a minimum of 4 cycles of therapy; three patients required 12 cycles before disease control. The duration of therapy in these ten patients has been 16 to 23 months (mean, 19.3 months) with no treatment-induced side effects. Extraocular mucosal lesion resolution has occurred in all but one patient, Visual acuity has stabilized or improved in all ten patients, and subjective complaints of discomfort and photophobia have decreased in all patients.

CONCLUSIONS

Intravenous immunoglobulin immunomodulatory therapy can be a safe and effective therapy for otherwise treatment-resistant ocular cicatricial pemphigoid.

Contemporary issues in the diagnosis of oral pemphigoid: a selective review of the literature

Pemphigoid is a group of bullous diseases that have a diversified morphologic presentation and affect the skin, oral mucosa, and other mucosal membranes, alone or in combination. In the literature, the condition has been subclassified into bullous pemphigoid and cicatricial pemphigoid (mucous membrane pemphigoid) on the basis of the primary organ of involvement. In addition to the clinical presentation and a subepithelial vesicle or bullae on routine histologic analysis, the diagnosis is based on direct and indirect immunofluorescence studies. Recent investigations indicate that different clinical groups of patients with pemphigoid produce autoantibodies to different molecules within the basement membrane zone. Based on these recent observations and a review of the literature, a viewpoint is presented that not all patients with cicatricial pemphigoid should be grouped together. Rather, they should be classified into subgroups-ocular, oral, etc-on the basis of the clinical phenotype and long-term follow-up. Such a division will facilitate the provision of appropriate and relevant treatment plans; if the clinical course changes, the diagnosis can be adjusted. This strategy will prevent patients with disease limited to the oral cavity from receiving systemic drugs or agents that may be more harmful than beneficial.

Update on mucous membrane pemphigoid: a heterogeneous immune-mediated subepithelial blistering entity

Most oral involvement in the skin diseases (dermatoses) is related to mucous membrane pemphigoid or lichen planus. Mucous membrane pemphigoid was the subject of a European Symposium held in Turin, Italy, in June 1997. This review is based on that symposium. Mucous membrane pemphigoid is a subepithelial vesiculobullous disorder mainly of late middle age; it has a slight predilection for women. Whereas mucous membrane pemphigoid was formerly considered a single entity, it is now quite evident that a number of subepithelial vesiculobullous disorders may produce similar clinical pictures and also that a range of variants of mucous membrane pemphigoid exists, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated subepithelial blistering diseases has therefore been used. Diagnosis and management of immune-mediated subepithelial blistering diseases on clinical grounds alone are impossible; a full history, general and oral examinations, and biopsy with immunostaining are now invariably required, sometimes supplemented with other investigations. Most patients with mucous membrane pemphigoid affecting the mouth manifest desquamative gingivitis, a fairly common complaint typically seen in women who are middle-aged or older. Oral vesicles and erosions may also occur, and there can be a positive Nikolsky sign. Some patients have lesions of other stratified squamous epithelia, presenting as conjunctival, nasal, oesophageal, laryngeal, vulval, penile, or anal involvement. Apart from improving oral hygiene, immunomodulatory-in particular, immunosuppressive-therapy is typically required to control oral lesions in mucous membrane pemphigoid. No single treatment regimen reliably controls all these disorders.

A child with localized vulval pemphigoid and IgG autoantibodies targeting the C-terminus of collagen XVII/BP180

Localized vulval pemphigoid of childhood (LVPC) has previously been reported in six girls. Clinical features and immunopathological data have suggested it to be a morphological variant of bullous pemphigoid. Epitope targets of the autoantibodies of these patients have not been defined in detail. We describe a 9-year-old girl with possible cicatricial LVPC and circulating IgG antibodies directed against native collagen XVII/BP180, its 120-kDa soluble ectodomain and against the C-terminus of collagen XVII/BP180. No reactivity was detected towards the NC16A domain of collagen XVII/BP180. Linear IgG and C3 deposits were found along the cutaneous basement membrane zone. On 1 mol/L salt-split skin, IgG autoantibodies were shown to bind to the epidermis, and the HLA type II allele DQB1*0301, a marker with significantly increased occurrence in patients with ocular and oral cicatricial pemphigoid, was identified in this patient. Our data suggest that LVPC is a variant of bullous pemphigoid in which direct immunofluorescence microscopy combined with immunoblot analysis can deliver valuable diagnostic information for differential diagnosis. However, differentiation between the scarring and non-scarring course of the disease cannot be made with the present diagnostic markers and therefore careful follow-up of patients with LVPC is required.