Clinical characteristics, mortality, and prognostic factors for bullous pemphigoid in a Thai population

Bullous pemphigoid is an uncommon, autoimmune, blistering disease. Clinical features, associated conditions, and outcomes differ according to country. We aimed to determine the mortality rate and clinical characteristics of Thai patients and to evaluate the risk factors associated with survival.A retrospective analysis was conducted on 119 patients, over a ten-year period, at Songklanagarind Hospital, the largest tertiary university hospital in Southern Thailand.The median age of onset was 82 years [interquartile range 72, 90], and 60 (50.4%) patients were men. The underlying diseases were hypertension (53.8%), neurological disease (42.8%), and diabetes mellitus (31.9%). Fifty-eight patients (48.7%) experienced pruritus, and 61.3% of patients had mild cutaneous lesions (less than 10% of the body surface area) on the day of diagnosis. Nine percent of patients presented with mucosal involvement. Complete blood counts showed anemia (32.8%), neutrophilia (30.3%), and eosinophilia (42.9%). The 1-, 3- and 5-year overall mortality rates were 28.1% [95% confidence interval (CI), 7.8-36.6], 55.7% (95% CI, 44.4-64.7) and 71.9% (95% CI 59.9-80.2), respectively. On multivariate analysis, high neutrophil/lymphocyte ratio [odds ratio (OR) 5.55, P < .001] and anemia (OR 2.93, P = .025) were found to be independently associated with mortality rate, whereas disease remission (OR 0.25, P = .003) was demonstrated to be a good prognostic factor.This is the first study to analyze the mortality rate of Bullous pemphigoid in Thailand. Mortality was associated with high neutrophil/lymphocyte ratio and anemia.

Prospective study in bullous pemphigoid: association of high serum anti-BP180 IgG levels with increased mortality and reduced Karnofsky score

BACKGROUND

Bullous pemphigoid (BP) is a subepidermal blistering disease characterized by autoantibodies against the two hemidesmosomal proteins, BP180 (type XVII collagen) and BP230. The multicentre prospective BLISTER (Bullous Pemphigoid Steroids and Tetracyclines) trial randomized 253 patients with BP to compare the benefits and harms between initial treatment with doxycycline or prednisolone.

OBJECTIVES

To analyse distinct autoantibody profiles for the prediction of the disease course in a well-characterized cohort of BP sera.

METHODS

One hundred and forty-three patients of the BLISTER trial consented to participate in this serological study. Sera taken at baseline were analysed by (i) indirect immunofluorescence, (ii) anti-BP180 NC16A (16th noncollagenous domain) and anti-BP230 enzyme-linked immunosorbent assay and (iii) immunoblotting with various substrates. Results were then linked with clinical parameters including age, Karnofsky score, number of blisters, related adverse events and mortality.

RESULTS

Disease activity correlated with immunoglobulin (Ig)G anti-BP180 levels but not with levels of anti-BP230 IgG and anti-BP180 IgE. High levels of both anti-BP180 IgG and anti-BP230 IgG were associated with a low Karnofsky score. The presence of anti-BP230 IgG was more frequent in older patients. Those with higher total IgE serum levels suffered from fewer adverse events. Higher IgG anti-BP180 levels were associated with an increased 1-year mortality rate.

CONCLUSIONS

Analysis of the autoantibody profile is not only of diagnostic relevance but may also be helpful in predicting the course of the disease.

A multi-hit hypothesis of bullous pemphigoid and associated neurological disease: Is HLA-DQB1*03:01, a potential link between immune privileged antigen exposure and epitope spreading?

Bullous pemphigoid (BP) is the most common autoimmune blistering disease and is linked to IgG recognition of 2 hemidesmosomal antigens, that is, BP230 (BP antigen 1) and BP180 (BP antigen 2, collagen XVII). The association of BP with other systemic diseases, particularly neurocognitive diseases, provides a potential clue in the underlying pathogenesis of BP. The role of HLA-DQB1*03:01 binding to the immunogenic portion of BP180 provides a potential mechanism by which exposure to neuronal collagen BP180 may lead to cutaneous disease. In our proposed multi-hit hypothesis, patients with underlying neuronal disease are exposed to previously sequestered self-antigen, most importantly BP180. Patients with the HLA-DQB1*03:01 allele show an increased T-cell avidity to several epitopes of BP180, particularly the BP180-NC16a domain. Thus, they have a genetic susceptibility to developing BP upon exposure to the target antigen. In a patient with dysregulation of Th1/Th2 balance, anergy is lost and T-cells are subsequently primed resulting in the development of functional autoimmunity against the BP180-NC16a domain leading to clinically overt disease.

Increased Levels of the Bullous Pemphigoid BP180 Autoantibody Are Associated with More Severe Dementia in Alzheimer's Disease

Bullous pemphigoid (BP) is a subepidermal blistering skin disease, which has shown a strong association with neurological diseases in epidemiological studies. The BP autoantigens BP180 and BP230 are expressed in the cutaneous basement membrane and the central nervous system. Using BP180 and BP230 ELISA assays and immunoblotting against BP180, we analyzed the IgG reactivity in the sera of 115 patients with Alzheimer's disease (AD) and 40 neurologically healthy controls. BP180 autoantibodies were found in 18% of patients with AD, whereas only 3% of controls had positive results (P = 0.019). BP230 values were higher and more often elevated in patients with AD than controls, but not significantly. None of the positive AD sera that recognized the full-length human BP180 in immunoblotting reacted with the cutaneous basement membrane in indirect immunofluorescence analysis. Moreover, a retrospective evaluation of the hospital records of the patients with AD revealed neither BP diagnosis nor BP-like symptoms. Interestingly, increased BP180-NC16A autoantibody values correlated with cognitive decline measured by mini-mental state examination scores, but not with the concentration of AD biomarkers in cerebrospinal fluid. Our findings further the understanding of the role of BP180 as a shared autoantigen in neurodermatological interactions and the association between BP and neurodegenerative diseases.

Epitope-Dependent Pathogenicity of Antibodies Targeting a Major Bullous Pemphigoid Autoantigen Collagen XVII/BP180

In bullous pemphigoid, the common autoimmune blistering disorder, IgG autoantibodies target various epitopes on hemidesmosomal transmembrane collagen XVII (COL17)/BP180. Antibodies (Abs) targeting the extracellular noncollagenous 16th A domain of COL17 may be pathogenic; however, the pathogenic roles of Abs targeting non-noncollagenous 16th A regions are poorly understood. In this study using a pathogenic and a nonpathogenic monoclonal antibody (mAb) targeting the noncollagenous 16th A domain (mAb TS39-3) and the C-terminus domain (mAb C17-C1), respectively, we show that endocytosis of immune complexes after binding of Abs to cell surface COL17 is a key phenomenon that induces skin fragility. Passive transfer of IgG1 mouse mAb TS39-3 but not mAb C17-C1 induces dermal-epidermal separation in neonatal human COL17-expressing transgenic mice. Interestingly, mAb C17-C1 strongly binds with the dermal-epidermal junction of the recipient mice skin, suggesting that binding of Abs with COL17 is insufficient to induce skin fragility. In cultured normal human epidermal keratinocytes treated with these mAbs, mAb TS39-3 but not mAb C17-C1 internalizes immune complexes after binding with cell surface COL17 via macropinocytosis, resulting in reduced COL17 expression. This study shows that pathogenicity of Abs targeting COL17 is epitope dependent, which is associated with macropinocytosis-mediated endocytosis of immune complexes and finally results in the depletion of COL17 expression in basal keratinocytes.

Deletion of the major bullous pemphigoid epitope region of collagen XVII induces blistering, autoimmunization, and itching in mice

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering skin disease with a characteristic of pruritus and blistering. BP patients carry inflammation-triggering autoantibodies against the collagen XVII (ColXVII, also known as BP180) juxtamembraneous extracellular noncollagenous 16A (NC16A) domain involved in ectodomain shedding. Deletion of the corresponding NC14A region in a genetically modified mouse model (ΔNC14A) decreased the amount of ColXVII in skin, but it did not prevent ectodomain shedding. Newborn ΔNC14A mice had no macroscopic phenotypic changes. However, subepidermal microblisters, rudimentary hemidesmosomes, and loose basement membrane zone were observed by microscopy. ΔNC14A mice grow normally, but at around 3 months of age they start to scratch themselves and develop crusted erosions. Furthermore, perilesional eosinophilic infiltrations in the skin, eosinophilia, and elevated serum IgE levels are detected. Despite the removal of the major BP epitope region, ΔNC14A mice developed IgG and IgA autoantibodies with subepidermal reactivity, indicating autoimmunization against a dermo-epidermal junction component. Moreover, IgG autoantibodies recognized a 180-kDa keratinocyte protein, which was sensitive to collagenase digestion. We show here that ΔNC14A mice provide a highly reproducible BP-related mouse model with spontaneous breakage of self-tolerance and development of autoantibodies.

Childhood Bullous Pemphigoid: Report of Three Cases

Bullous pemphigoid (BP) is a disorder that rarely occurs in children. We hereby describe three cases of childhood BP aged 2-4 months, which are among the youngest reported in the literature. BP was confirmed by histopathology, direct and indirect immunofluorescence with salt-split skin test and immunoblotting. These patients were successfully treated with systemic corticosteroids with a complete clinical remission.

Bullous pemphigoid: role of complement and mechanisms for blister formation within the lamina lucida

Bullous pemphigoid (BP), an autoimmune subepidermal blistering skin disease, demonstrates tense blisters with or without widespread erythema, blistering along the lamina lucida, immunoglobulin G and/or complement deposits at the basement membrane zone, and the presence of circulating autoantibodies against hemidesmosomal molecules. These autoantibodies usually react against 180-kDa and/or 230-kDa proteins, designated as BP180 and BP230, respectively. The precise blistering mechanisms after autoantibodies bind to antigens are not fully understood. Immune complexes are thought to initially activate the complement cascade, which may induce activation of proteases and/or cytokines and cause dermal-epidermal separation. However, why does separation run specifically within the lamina lucida in a space as narrow as 500 nm wide? This review mainly focuses on the possible mechanisms of BP-specific blistering and how separation occurs along the lamina lucida, based on existing evidence.

Blistering rash in an older man

The patient kept hoping that the rash would go away on its own, but as time went by the rash spread and the pain became intolerable.

Pemphigoid diseases

Pemphigoid diseases are a group of well defined autoimmune disorders that are characterised by autoantibodies against structural proteins of the dermal-epidermal junction and, clinically, by tense blisters and erosions on skin or mucous membranes close to the skin surface. The most common of these diseases is bullous pemphigoid, which mainly affects older people and the reported incidence of which in Europe has more than doubled in the past decade. Prognosis and treatments vary substantially between the different disorders and, since clinical criteria are usually not sufficient, direct immunofluorescence microscopy of a perilesional biopsy specimen or serological tests are needed for exact diagnosis. In eight pemphigoid diseases the target antigens have been identified molecularly, which has allowed the development of standard diagnostic assays for detection of serum autoantibodies-some of which are commercially available. In this Seminar we discuss the clinical range, diagnostic criteria, diagnostic assay systems, and treatment options for this group of diseases.

Peristomal and generalized bullous pemphigoid in patients with underlying inflammatory bowel disease: is plectin the missing link?

Bullous pemphigoid (BP) is a blistering disorder of the skin and mucosa that may coexist with inflammatory bowel disease (IBD). The authors' experiences with peristomal and generalized BP in five patients (three with ulcerative colitis [UC] post colostomy surgery and two with Crohn's disease [CD] post ileostomy surgery, time since surgery 5 to 20 years) is described. The patients presented with peristomal blisters and erosions, subsequently confirmed as BP by skin biopsy. Treatments for the skin disease included potent alcohol-based topical corticosteroids, oral tetracyclines, and oral corticosteroids. In three patients (two with UC, one with CD), the initially localized peristomal disease later became generalized across the skin; these patients were more likely to require systemic immunosuppressive therapy. Because an involvement of plectin, a cytoskeletal protein that attaches skin and mucosal cells to their extracellular matrix, in IBD has been shown, it is possible that this protein forms the missing link between IBD and BP via epitope spreading. The inflammation of IBD exposes plectin, stimulating a secondary immune response that may, in susceptible individuals, crossreact with the skin, provoking BP. Further research into this area could enable clinical testing for plectin auto-antibodies in patient sera, possibly preempting the development of BP and expediting the initiation of early effective treatment.

Acquired hemophilia associated with bullous pemphigoid: a case report

The development of factor VIII inhibitors in non-hemophilic patients is rare and may occur in healthy individuals, mostly elderly and women in postpartum period, and in patients with malignant neoplasia or autoimmune diseases, such as bullous pemphigoid. We described the case of a 60-year-old female patient who developed bullous pemphigoid for 3 month and presented with bleeding tendency and hematoma in the tongue. Therapy with methylprednisolone, cyclophosphamide, intravenous immunoglobulin and factor VIII reposition was instituted, resulting in a remission of the bleeding and negativity for antibodies against factor VIII titers. We concluded that, despite its rarity, the presence of acquired factor VIII inhibitors should be investigated when patients with autoimmune diseases develop bleeding manifestations.

IgA anti-p200 pemphigoid

BACKGROUND

Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disorder. Clinically, it may resemble bullous pemphigoid, linear IgA bullous dermatosis, or dermatitis herpetiformis. Immunologically, anti-p200 pemphigoid is characterized by the development of IgG antibodies directed against a basement membrane zone protein with a molecular weight of 200 kDa.

OBSERVATIONS

We report the first case, to our knowledge, of anti-p200 pemphigoid associated with IgA antibodies and having clinical features resembling pemphigus herpetiformis or dermatitis herpetiformis localized on traumatized areas. Histopathological examination of lesional skin showed dermal-epidermal separation and microabscesses composed of neutrophils in the dermal papillae. Direct immunofluorescence disclosed the presence exclusively of linear in vivo-bound IgA along the basement membrane zone. With the use of laser scanning confocal microscopy, in vivo-bound IgA was localized above collagen type IV and colocalized with laminin 332. Indirect immunofluorescence showed circulating IgA antibodies against basement membrane zone at a titer of 1:160 that reacted with the floor of an artificial blister of salt-split skin. Western immunoblot analysis using dermal extract confirmed the reactivity of circulating IgA antibodies with the 200-kDa antigen corresponding to laminin γ1; however, immunoblotting using recombinant protein of 107 amino acid C-terminus of laminin γ1 was negative for circulating IgA antibodies. Immunoelectron microscopy disclosed the reactivity of circulating IgA autoantibodies within the lower lamina lucida.

CONCLUSION

To the best of our knowledge, this is the first case fulfilling the immunopathological criteria for anti-p200 pemphigoid associated with IgA antibodies and having unusual clinical features.

Usefulness of BP230 and BP180-NC16a enzyme-linked immunosorbent assays in the initial diagnosis of bullous pemphigoid: a retrospective study of 138 patients

OBJECTIVE

To investigate the diagnostic value of commercially available BP230 and BP180-NC16a enzyme-linked immunosorbent assays (ELISAs) in routine practice in patients with bullous pemphigoid (BP).

DESIGN

Single-center retrospective study.

SETTING

French academic dermatology department.

PATIENTS

The study population comprised 138 patients, who were admitted from January 1998 through December 2008.

INTERVENTIONS

Sera samples were analyzed by ELISA; clinical and immunopathological data were recorded from the patients' medical charts.

MAIN OUTCOME MEASURES

BP230 and BP180-NC16a ELISA scores were evaluated with respect to clinical characteristics (number of blisters, mucosal involvement, localized or generalized disease, and outcome) and routine indirect immunofluorescence (IF).

RESULTS

Of the 138 study patients, 81 (59%) had a positive BP230 ELISA result and 119 (86%) had a positive BP180 ELISA result. There was no relationship between a positive ELISA BP230 result and the disease extent at diagnosis or the presence of mucosal involvement. Serum anti-basement membrane zone autoantibodies (indirect IF) were more frequently detected when the BP230 ELISA result was positive (P < .001). The median anti-basement membrane autoantibody titer as detected by indirect IF was higher in patients with a positive BP230 result (P < .001). The BP180 ELISA result was associated with disease extent at diagnosis as estimated by both the percentage of patients with extensive BP (P = .01) and the mean number of blisters (P = .03) but was not associated with mucosal involvement.

CONCLUSIONS

The currently available BP230 ELISA is a reliable although less-sensitive test than BP180 ELISA in BP, and its diagnostic added value compared with BP180 ELISA alone is approximately 5%. Our results support the predominant contribution of the BP230-specific autoantibodies to anti-basement membrane zone antibody titer as detected by indirect IF.

Prevalence and clinical features of Thai patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is a rare, subepidermal autoimmune blistering disease. Studies from different regions show discrepancies in clinical features and courses.

OBJECTIVES

To reveal clinical characteristics, investigations and clinical outcomes of Thai patients with BP and to evaluate the association of BP with malignancy, diabetes mellitus and neurologic diseases.

METHODS

Patients diagnosed as BP who had visited the autoimmune skin clinic at Siriraj Hospital between 1991 and 2009 were retrospectively studied.

RESULTS

Fifty-eight patients were enrolled. Mean age of onset was 69.3 years. The female to male ratio was 2.7:1. Fifteen percent of the patients had mucosal involvement and 38.9% showed peripheral blood eosinophilia. The sensitivity of the direct and indirect immunofluorescence test in the diagnosis of BP was 95.7% and 73.5%, respectively. The frequency of diabetes mellitus in BP patients was significantly higher than that in the general population (p < 0.001). BP patients had a significantly higher chance of having neurologic diseases compared with other autoimmune vesiculobullous disease patients (adjusted odd ratios 4, 95% confidence interval 1.2-13.3). Disease control was achieved in 89.7% of the patients. One-year and three-year 6.4% remission rate was and 66.3%, respectively.

CONCLUSIONS

BP usually occurred in the seventh and eighth decade of life and affected females more than males. BP is associated with diabetes mellitus and neurologic diseases. Corticosteroids are the mainstay of the treatment. Two-thirds of patients are likely to be in remission within three years.

What lies beneath the surface of the itch in adults?

Pruritus is synonymous with itching. Many medical conditions are complicated by chronic pruritus compromising the patient's quality of life. The majority of pruritic stimuli are transmitted through C fibers into the lateral spinothalamic tract and then into the somatic sensory cortex where the itching is detected. Histamine, substance P, and tumor necrosis factor a play significant roles in the perception of pruritus. Medical conditions in adults with significant pruritus will be defined in this review.

Bullous pemphigoid: physiopathology, clinical features and management

There has been a considerable progress in the understanding of the physiopathology of BP during the past 2 decades. The insights into the humoral and cellular immune response against BP180 and BP230 have increased significantly. Nevertheless, the factors underlying the initiation of the disease leading to a disruption of self-tolerance remain unclear. Clinically, the disease shows protean presentations, and diagnostic delay is common. A practical, relevant, and unresolved question is how to identify patients suffering from BP at an early stage of the disease, when direct immunofluorescence microscopy findings still may be negative. The characterization of markers allowing the differentiation of BP from other pruritic eruptions occurring in the elderly population would be extremely helpful in daily practice. Finally, despite the knowledge that potent topical steroids are efficient in controlling the disease, management of BP sometimes remains difficult and requires systemic therapies. It is hoped that a better knowledge of the regulation of the autoimmune response in BP also will facilitate the design of novel immunomodulatory therapeutic approaches devoid of the severe side effects of current immunosuppressive treatments.

[Dermatoses specific for pregnancy period]

The study presents dermatoses specific to the pregnancy period, like intrahepatic cholestasis of pregnancy, pruritic urticarial papules and plaques of pregnancy (PUPPP), impetigo herpetiformis, gestational pemphigoid, papulous and papulo-pustulous dermatitis.

Blistering disorders: diagnosis and treatment

Blistering diseases are a heterogeneous group of disorders that can affect either skin and mucous membrane, or both, varying in presentation, clinical course, pathohistology, immunopathology and treatment. Not infrequently the diagnosis is delayed. This can result in severe, and sometimes fatal consequences. Although these diseases are rare, it is very important to make an accurate diagnosis based on a combination of clinical profile and laboratory observations. A brief review is presented of the following bullous diseases: pemphigus, paraneoplastic pemphigus, bullous pemphigoid, cicatricial pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis, linear IgA bullous disease, porphyria cutanea tarda, and subcorneal pustular dermatitis. Their clinical, pathohistologic and immunopathologic features and recommendations for therapy are discussed.

Specific dermatoses of pregnancy: an evidence-based systematic review

OBJECTIVE

We conducted an evidence-based systematic analysis of the literature on specific dermatoses of pregnancy.

STUDY DESIGN

The bibliographic databases MEDLINE and EMBASE were screened for studies and reports in all languages about herpes gestationis, pruritic urticarial papules and plaques of pregnancy, pruritic folliculitis of pregnancy, and prurigo of pregnancy from January 1962 to January 2002. As main index terms, including analogs and derivatives, we used the names of specific dermatoses of pregnancy. Intrahepatic cholestasis of pregnancy, not a primary dermatosis, was included herein because this disorder is associated with pregnancy and its secondary skin manifestations must be differentiated from specific dermatoses of pregnancy. Other sources were abstract books of symposia and congresses, theses, textbooks, monographs, reviews, editorials, letters to the editor, free or rapid communications, and the reference lists from all the articles that were retrieved. All articles selected for inclusion in this review were evaluated critically with regard to their impact factor and evidence-based contribution to this field, as measured by their citation index and impact factor of the journal in which they were published. Approximately 39% of articles met the selection criteria.

RESULTS

The clinical features and prognosis of the specific dermatoses of pregnancy have been delineated through a number of retrospective and cohort studies. The molecular biologic and immunogenetic properties of herpes gestationis, pruritic urticarial papules and plaques of pregnancy, and intrahepatic cholestasis of pregnancy have been further clarified. A meta-analysis in this review reveals a higher prevalence of multiple gestation pregnancy (11.7%) among patients with pruritic urticarial papules and plaques of pregnancy. Several investigations have unraveled the fetal complications in intrahepatic cholestasis of pregnancy and herpes gestationis. New treatment modalities in intrahepatic cholestasis of pregnancy (cholestyramine, ursodeoxycholic acid) and herpes gestationis (cyclosporin, intravenous immunoglobulin, and tetracyclines postpartum) have shown promise and warrant further evaluation.

CONCLUSION

During the past few decades, a significant amount of new data has provided new insights into the classification, pathogenesis, treatment, prognosis, and fetal risks that are associated with the specific dermatoses of pregnancy.

BP180 ELISA using bacterial recombinant NC16a protein as a diagnostic and monitoring tool for bullous pemphigoid

Bullous pemphigoid (BP) is an acquired autoimmune subepidermal blistering disease against hemidesmosomal cytoplasmic BP230 and transmembrane BP180 proteins. Epitope mapping studies have shown that the membrane-proximal noncollagenous (NC) 16a domain of BP180 harbors clusters of antigenic sites recognized by the vast majority of BP sera. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) using bacterial recombinant NC16a protein and evaluated its clinical benefit for diagnosis and monitoring disease activity. Fifty four (84.4%) of 64 sera from BP patients were positive, while only one (1.1%) of 91 sera from collagen disease patients and five (1.5%) of 336 sera from normal control barely exceeded the cut-off value. None of 69 pemphigus vulgaris sera and none of 42 pemphigus foliaceus sera exceeded the cut-off value. Thus, the sensitivity and specificity of NC16a ELISA were 84.4 and 98.9%, respectively. The correlation between ELISA scores and disease activity along the time course was examined using seven BP patients. NC16a ELISA scores tended to fluctuate in parallel with the disease activity along the time course and reflected the disease activity much better than indirect immunofluorescence. These findings indicate that NC16a ELISA will be a valuable tool not only for the diagnosis of patients with BP but also for the monitoring of the disease activity.

A case of bullous pemphigoid limited to psoriatic plaques

Psoriasis occurs with increased incidence in patients with bullous pemphigoid (BP). In this article, we describe the seventh reported English literature case in which the bullous lesions were limited to psoriatic plaques, and we discuss the pathophysiologic mechanisms that might explain this phenomenon. Treatment with acitretin quickly cleared both psoriatic and bullous lesions, suggesting a direct link between the psoriatic inflammatory process and the evolution of bullous lesions.

Bullous diseases in the elderly

The elderly are prone to several autoimmune bullous diseases that have significant morbidity, and an accurate diagnosis is essential for proper management. It is important to be aware of the potential adverse effects of the various systemic agents that can be used.

[The mosaic of pemphigus]

Pemphigus is an autoimmune blistering disease of skin and mucous membranes. The classic types of pemphigus are pemphigus vulgaris and pemphigus foliaceus. In this review we summarize recent advancement in the etiology and the pathogenesis of pemphigus. Desmogleins--transmembrane glycoproteins involved in intracellular adhesion--were recognized as targets of pemphigus antibodies. It was found that the distribution and the expression of desmogleins can explain the difference in the localization of lesions in pemphigus vulgaris and pemphigus foliaceus. Pemphigus develops in a two-step process. The first step leads to the presence of a low titer of autoantibody, the second step results in a significant increase in the antibody titer which causes the clinical stage of the disease. Selective presentation of self peptides can explain the Major Histocompatibility Complex (MHC)--linked susceptibility to autoimmune diseases including pemphigus and rheumatoid arthritis. Peptides selective for the disease-associated molecules can be identified and used to search for microbiologic factors that can take part in the pathogenesis of pemphigus.

Bullous pemphigoid: end of the century overview

Bullous pemphigoid (BP) was first described by Lever in 1953 as a subepidermal blistering disease. Immunohistological features of BP include dermal-epidermal junction separation with an inflammatory cell infiltrate in the upper dermis, and autoantibodies in patients' circulation and bound to the basement membrane zone (BMZ). These autoantibodies show a linear staining at the dermal-epidermal junction (DEJ) and recognize two major hemidesmosomal proteins, the BP230 (BPAG1) and BP180 (BPAG2). An IgG passive transfer mouse model of BP was developed, that recapitulates the key features of human BP. Using this in vivo model system, key cellular and molecular events leading to BP disease phenotype are identified, including IgG binding to its target, complement activation, mast cell degranulation, neutrophil infiltration and activation. Proteinases and reactive oxygen species released by neutrophils work together to damage BMZ, causing DEJ separation. T cells from BP patients show a specific proliferative response to recombinant BP180 NC16A. These NC16A-responding T lymphocytes express alpha/beta T cell receptors and CD4 memory T cell surface markers and exhibited a Th1/Th2 mixed cytokine profile. After almost a half-century of studies, we have learned a great deal about IgG-mediated tissue injury and begin to understand the autoimmune responses leading to pathogenic IgG production in BP.

Clinical significance of enzyme-linked immunosorbent assay for the detection of circulating anti-BP180 autoantibodies in patients with bullous pemphigoid

The NC16A domain of the 180-kDa bullous pemphigoid antigen (BP180) is the most immunogenic and, probably, pathogenic region in bullous pemphigoid (BP). In the present study, in order to determine whether serum level of circulating anti-BP180 autoantibodies is a valuable serum marker in BP, the immunoreactivity of sera against the NC16A domain of BP180 was measured using enzyme-linked immunosorbent assay (ELISA) in ten patients with BP. Serum levels of anti-BP180 autoantibodies correlated with the clinical course in BP patients, who received various therapeutic agents. The result suggests that this NC16A-ELISA is a useful method for evaluating the clinical course and efficacy of the therapy in patients with BP.

Pemphigoid gestationis: a review

Pemphigoid gestationis is a rare autoimmune vesiculobullous skin disease closely related to the pemphigoid group of blistering disorders. It is unique in that it is most frequently associated with pregnancy. Diagnosis is made on the basis of the presence of a subepidermal vesicle on routine histologic examination and of linear deposition of the third component of complement along the basement membrane zone of perilesional skin. Abnormal expression of major histocompatibility complex class II molecules in the placenta may trigger the initiating immunologic event in this organ, which is followed by cross-reactivity with an antigen present in the skin and the characteristic cutaneous signs of the disease. The immunogenetics of this disorder are interesting. A role for the involvement of major histocompatibility complex class II antigens seems likely because of the association with human leukocyte antigens DR3 and DR4. Major histocompatibility complex class III associations have also been observed, as has a high frequency of anti-human leukocyte antigen antibodies. We review the current understanding of the molecular biologic and immunogenetic properties of this disease and discuss treatment and potential impact on the fetus.

Pemphigoid: clinical, histologic, immunopathologic, and therapeutic considerations

Autoimmune blistering diseases are generally distinct entities characterized by relatively consistent clinical, histologic, and immunopathologic findings. These disorders may cause impaired adhesion of epidermis to epidermal basement membrane (eg, the pemphigoid group of disorders [bullous, gestational, and mucous membrane]) or impaired adhesion of epidermal cells to each other (eg, the pemphigus group of disorders). Recent studies have shown that these disorders are characterized by autoantibodies that often display pathogenic (ie, blister-forming) activity in passive transfer models. Interestingly, the autoantigens targeted by these patients' autoantibodies represent important structural proteins that promote cell matrix (eg, pemphigoid) or cell-to-cell (eg, pemphigus) adhesion in skin. Autoimmune blistering diseases are characterized by substantial morbidity (pruritus, pain, disfigurement), and in some instances, mortality (secondary to loss of epidermal barrier function). Treatment with systemic immunosuppressives has reduced morbidity and mortality in patients with these diseases. JAMA. 2000;284:350-356

Presence of interleukin 10 in the serum and blister fluid of patients with pemphigus vulgaris and pemphigoid

Interleukin 10 (IL-10) is an immunoregulatory cytokine produced by T lymphocytes and macrophages. Recently, it has been suggested that IL-10 may be involved in the pathogenesis of various inflammatory and autoimmune diseases. Using an ELISA we investigated the presence of IL-10 in the serum and blister fluid of pemphigus vulgaris (PV) patients with active disease and those in prolonged clinical remission compared with normal controls. Sera from patients with bullous pemphigoid (BP), ocular cicatricial pemphigoid (OCP), oral pemphigoid (OP) and blister fluid from five patients with BP were also studied. Increased levels of IL-10 were detected in the sera of 87.5% of patients with active PV and were statistically significant (P=0.0003) when compared with levels in normal human serum. Lower levels of IL-10 were detected in 12.5% PV patients in remission and were statistically significant (P=0.0001) when compared with levels in patients with active disease. Levels of IL-10 were detected in sera of 4.6% (1 of 24) of the normal controls. The levels of IL-10 were approximately four times higher in blister fluids than levels in the serum in the same PV patients. This difference was highly statistically significant (P=0.0008). A correlation was observed between serum levels of IL-10 and titres of pemphigus autoantibodies and with disease severity. Elevated level of IL-10 was detected in the blister fluid from five BP patients. Levels of IL-10 in the sera of patients with BP, OCP and OP were not significantly increased. These preliminary data suggest that IL-10 in concert with other cytokines may play an important role in the pathogenesis of PV and BP.

Cytokines and bullous pemphigoid

This report reviews the data presented in the literature concerning the presence and levels of different cytokines in sera, lesional tissue or blister fluids of patients with bullous pemphigoid. The list of cytokines analysed includes 21 molecules: interleukins (IL)-1 => 8, IL-10 => 13, IL-15, granulocyte-monocyte-colony stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), oncostatin-M (OSM), regulated upon activation normal T cell expressed and presumably secreted (RANTES), transforming growth factor-beta 1 (TGF-beta 1), tumor necrosis factor-alpha (TNF-alpha) and vascular endothelial growth factor (VEGF). Basic information regarding the functions of these cytokines and their possible involvement in the pathogenetic steps of the disease, such as autoantigen expression, autoantibody induction, complement activation, local cell recruitment and stimulation, resident cell activation, release of various effector molecules and tissue damage are also reported. A specific function for each cytokine in bullous pemphigoid induction cannot be still defined, however, the literature attributes a major role to IL-1, IL-4, IL-5, IL-6, IL-8 and IFN-gamma. On the basis of significant (direct or inverse) correlations found between disease intensity and the blister fluid/serum levels, the following cytokines IL-7, IL-15, RANTES, VEGF and TNF-alpha, besides those previously mentioned, may also be involved in this disease.

IgG autoantibodies from bullous pemphigoid (BP) patients bind antigenic sites on both the extracellular and the intracellular domains of the BP antigen 180

Bullous pemphigoid (BP) and gestational pemphigoid (PG) are subepidermal blistering disorders associated with autoantibodies directed against two components of hemidesmosomes: the BP antigen 180 (BP180) and the BP antigen 230 (BP230). Autoantibodies against the extracellular domain (ECD) of BP180 are thought to play an initiatory role in subepidermal blister formation. To characterize the targeted antigenic sites on BP180, we have assessed the reactivity of sera from BP and PG patients against eukaryotic recombinant proteins encompassing various portions of the ECD and the intracellular domain (ICD) of BP180. Twenty-two of 22 (100%) BP sera that immunoblotted BP180 in keratinocyte extracts, bound a mutant form consisting of the entire ECD of BP180, whereas only three of these 22 sera (14%) reacted against the ECD of BP180 lacking the NC16A membrane proximal region. Thirteen out of the 22 (59%) BP sera recognized the ICD of BP180. Circulating IgG from a representative BP patient that was affinity purified against the ECD of BP180 did not bind the ICD when reblotted, indicating that there was no antigenic cross-reactivity between the ECD and the ICD of BP180. Reactivity against the ICD of BP180 was further ascertained by immunofluorescence microscopy studies showing that nine of the 22 (41%) BP sera stained COS-7 cells expressing the ICD of BP180. Using deletion mutants of the ICD of BP180, the majority of the sera was found to recognize the central region of the ICD of BP180. Specifically, an immunodominant region was localized to an 87-amino acid segment located towards the NH2-terminus of BP180. In contrast to BP sera, five of six (83%) PG sera contained IgG that recognized exclusively the NC16A region, whereas none bound to the ICD of BP180. Together, the results indicate that in BP, autoantibody reactivity to BP180 is not exclusively restricted to the NC16A region, but that additional antigenic determinants exist on the ICD of BP180. The observed heterogeneous immune response against BP180 might reflect intramolecular epitope spreading. Because the ICD ofBP180 harbors functionally important regions, it is possible that autoantibodies against the ICD of BP180 have pathogenic significance for the progression of the disease.

Hemidesmosomes and their unique transmembrane protein BP180

Hemidesmosomes are adhesion complexes responsible for linking keratin intermediate filaments of stratified and complex epithelia to components of the extracellular matrix such as collagen fibrils. Over the past several years, it has become clear that there are at least five hemidesmosomal proteins, including HD1/plectin and BP230 as cytoplasmic plaque proteins and integrin alpha6beta4 and BP180 as transmembrane proteins. Among them, BP180 is unique as a transmembrane protein because of its collagenous extracellular domain. Recent biochemical and ultrastructural analyses have revealed its molecular configuration and nature as a major component of anchoring filaments connecting hemidesmosomes to the basement membrane. These results indicate that BP180 is a new type of adhesion receptor. In addition to biochemical analyses of these hemidesmosomal proteins, recent studies on patients with inherited skin blistering diseases and on knockout mice have demonstrated roles in hemidesmosome formation and stabilization, as well as unexpected, novel functions.

Nonsteroidal treatment of autoimmune skin diseases

This brief survey has, it is hoped, helped to ease some of the anxiety associated with the management of complex autoimmune skin disorders. The main points to remember are that there are numerous therapeutic options for each disease. I like to think of this method of therapeutics as 'informed trial and error.' One does not need to master the monitoring, side-effect profile, or dosing regimen for each of the drugs in Table 1; only a working knowledge of a few is sufficient. I hope that the readers take advantage of the many tables and caveats I have included so this article can be a ready reference for many future uses.

IgE autoantibodies directed against the major bullous pemphigoid antigen in patients with a severe form of pemphigoid

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized in part by circulating and tissue-bound IgG autoantibodies directed against the basement membrane zone. In addition, most of the patients with BP have increased serum IgE levels which seem to be correlated with the disease activity, whereas the presence of circulating anti-basement membrane zone IgE Abs has been reported in some patients. To elucidate whether IgE-dependent mechanisms play a role in the physiopathology of BP, we looked for the presence of IgE Abs specifically directed against the major BP Ag (BPAg1) in sera of BP patients at the onset and after remission of the disease. A radioimmunoassay and a 55-kDa recombinant protein (rBP55) obtained from a cDNA sequence, encoding the C-terminal region of the BPAg1 and containing the BPAg1 immunodominant epitopes, were used. Anti-rBP55 IgE Abs were found in 12 of the 19 sera tested. When the patients were divided into two groups according to the disease severity, anti-rBP55 IgE Abs were found only in patients with a severe form of the disease. Cytophilic IgE was detected on approximately 20% of peripheral blood eosinophils purified from BP patients. Immunohistochemistry studies suggested that some of the IgE-bearing cells in the lesional skin of BP patients are eosinophils. Immunostaining experiments revealed the existence of FcepsilonRI on both peripheral blood and tissue eosinophils. Taken together, these results suggest that IgE-dependent mechanisms could participate in the constitution of the lesions in BP.

Bullous pemphigoid: persistent lesions of eczematous/urticarial erythemas

Two patients with bullous pemphigoid presented with pruritic eczematous or urticarial eruptions on the trunk. These nonbullous lesions had persisted throughout the course of disease with no blistering lesions for more than two years in each patient.

Serum levels of soluble CD23 in patients with bullous pemphigoid

In this study, we tested the serum levels of soluble CD23 (sCD23) in 27 bullous pemphigoid (BP) patients and compared them with the disease activity. Soluble CD23 is the cleaved portion of the low affinity Fc receptor for IgE (Fc epsilon RII/CD23) which has an affinity for IgE and regulates IgE synthesis. Although bullous pemphigoid (BP) is a subepidermal blistering disease characterized by IgG class autoantibodies against the basement membrane of stratified squamous epithelia, several IgE-related phenomena have been reported. Recently, we have shown that Fc epsilon RII-expressing and IgE-bearing cells are detectable in the lesional skin and concluded that an IgE-Fc epsilon RII/CD23 system may be involved in the pathogenesis of this disease. The serum level of sCD23 in BP patients was significantly higher than healthy controls (p < 0.01). In 11 out of 12 patients, the alteration of serum sCD23 levels correlated well with the disease activity. Thus the serum level of sCD23 is useful as a new parameter for assessing the level of disease activity in BP. High levels of sCD23 may represent part of an IgE-mediated immune reaction which may play a role in the pathogenesis of BP.

A possible cell-biologic mechanism involved in blister formation of bullous pemphigoid: anti-180-kD BPA antibody is an initiator

In this short review, we summarize the results of our recent studies on the effects of anti-bullous-pemphigoid antigen (BPA) antibodies and BP sera on the hemidesmosome in cultured keratinocytes (DJM-1 cells) as examined by immunofluorescence microscopy. The 180-kD and the 230-kD BPAs localized on the basal plasma membrane showed a homogeneously dotted pattern in cells grown with low Ca2+ (0.07 mM), while they formed a peculiar concentric ring or arch (ring/arch) pattern in cells grown with high Ca2+ (1.87 mM). In addition, the 180-kD BPA was distributed also on the lateral/apical cell membrane, and the 230-kD BPA was found in the cytoplasm. The high Ca2+ ring/arch arrangement of BPAs was formed within 3 h after the low-high Ca2+ switch. Anti-180-kD BPA monoclonal antibodies (MAbs) and BP sera, but not anti-230-kD BPA MAbs, which were added into this system, caused the internalization of the 180-kD BPA from the lateral/apical cell membrane and inhibited the formation of the ring/arch pattern. These results suggest that autoantibodies to the 180-kD, but not to the 230-kD, BPAs may directly bind to the antigen on the cell surface of the basal cells and disturb the formation of hemidesmosomes. The 180-kD BPA appears to be an initiator of blister formation.

Bullous pemphigoid sera induce bullous-pemphigoid-like lesions in neonatal mice pretreated with a limited dose of ultraviolet B irradiation

The role of bullous pemphigoid (BP) autoantibodies (Abs) in the pathogenesis of BP is unclear. Lack of a confirmed experimental animal model prevents studies of the pathogenetic role of BP Abs. We hypothesized that some alterations of BP antigens (BP Ags) will be necessary for causative binding of BP Abs to the Ags. To cause an artificial and reproducible alteration, neonatal mice were irradiated with ultraviolet B (UVB). After the irradiation of 600 mJ/cm2 of UVB, BP serum was intraperitoneally injected. When the BP sera, which recognized only the 230-kD BP Ag, or both 230- and 180-kD BP Ags, were transferred into the UVB-treated mice, erosions and vesicles appeared in 14-78% of the animals. Histopathological examination revealed subepidermal blister formation in the mice treated with UVB and BP sera. Electron microscopy demonstrated that the separation occurred at the level of the lamina lucida. Human IgG and C3 were deposited at the dermal-epidermal junction. Control animals to which healthy sera were injected after the same dose of UVB irradiation showed degeneration of the upper epidermis but no apparent dermal-epidermal cleft formation histopathologically. These results suggest that BP antibodies play a pathogenetic role in vivo. This animal model can contribute to a study of the pathogenesis of BP.