Recent advances in the study of the pathophysiology of pemphigus

Erythema multiforme-like lip presentation in pemphigus vulgaris patients: a multicenter case series

Pemphigus vulgaris (PV) is a chronic autoimmune mucocutaneous blistering disease. Autoantibodies are directed against desmogleins, leading to the formation of intraepithelial bullae. PV, as with other autoimmune mucocutaneous disorders of the oral cavity, presents diagnostic and therapeutic challenges. Approximately 50-70% of cases present first with oral lesions. The lesions commonly start as vesicles or bullae that rapidly rupture, leading to erosions and ulcerations. The palatal, gingival, buccal, and labial mucosa are the most commonly affected sites. Oral PV can mimic several other diseases that cause mucosal erosions and/or ulcerations, including erythema multiforme (EM). EM is an acute, immune-mediated, self-limited hypersensitivity condition primarily associated with herpes simplex infection. Oral lesions can be variable, but a very characteristic presentation with labial hemorrhagic erosions, ulcerations and crusting is commonly seen. In this case series, we present six cases of PV: one male patient and five female patients whose ages ranged from 34 to 65 years old. All patients presented with hemorrhage and crusting of the lips in addition to multiple intraoral erosions and ulcerations. Three patients presented with oral and skin lesions. All patients underwent biopsies, and a diagnosis of PV was confirmed. All patients were treated with steroids (topical and systemic) and variable steroid-sparing agents. This case series emphasizes that oral PV may be misdiagnosed as EM in a subgroup of patients who present with persistent lip hemorrhage and crusting. Therefore, a comprehensive history, clinical examination and incisional biopsies should be considered in such patients.

Case Report: Variety of Target Antigens During 1 Year Follow-Up of a Patient Initially Diagnosed With Bullous Pemphigoid

Autoimmune bullous diseases (AIBDs), presenting cutaneous and/or mucosal bullous lesions, are classified into pemphigus and pemphigoid diseases. A longtime observation for complicated AIBD cases is rarely reported. In this study, serum samples of one AIBD patient were collected at seven different time points during the disease course including a relapse, which were examined by our conventional and newly developed methods for the detection of autoantibodies. Interestingly, we found changes of both the presence and the titers of various autoantibodies in accordance with the changes of clinical features during the whole disease course, which indicated that the patient started as bullous pemphigoid and relapsed as concurrence of bullous pemphigoid and mucosal-dominant-type pemphigus vulgaris.

Marked to Die-Cell Death Mechanisms for Keratinocyte Acantholysis in Pemphigus Diseases

Pemphigus is a group of blistering autoimmune diseases causing painful skin lesions, characterized by acantholysis and by the production of autoantibodies against, mainly, adhesion proteins. We reviewed the literature for molecules and/ or features involved in the 12 cell death pathways described by Nomenclature Committee on Cell Death, taking place in pemphigus patients, cell lines, or human skin organ cultures treated with sera or IgG from pemphigus patients or in pemphigus mouse models, and found 61 studies mentioning 97 molecules involved in cell death pathways. Among the molecules, most investigated were pleiotropic molecules such as TNF and CASP3, followed by FASL and CASP8, and then by FAS, BAX, BCL2, and TP53, all involved in more than one pathway but interpreted to function only within apoptosis. Most of these previous investigations focused only on apoptosis, but four recent studies, using TUNEL assays and/or electron microscopy, disqualified this pathway as a previous event of acantholysis. For PV, apoptolysis was suggested as a cell death mechanism based on pathogenic autoantibodies diversity, mitochondrial dysfunction, and p38 MAPK signaling. To answer those many questions that remain on cell death and pemphigus, we propose well-controlled, statistically relevant investigations on pemphigus and cell death pathways besides apoptosis, to overcome the challenges of understanding the etiopathology of pemphigus diseases.

Oral Pemphigus Vulgaris

Pemphigus is a chronic mucocutaneous autoimmune disease with the clinical feature of blisters that initially appear in the oral cavity and later in the skin. The dental professionals play an important role in diagnosing the disease. Early diagnosis and treatment determine the course and prognosis of the disease. Systemic corticosteroids continue to be the standard therapy for pemphigus vulgaris (PV). Management of PV involves prolonged use of steroids to control the disease and prevent relapses, but associated adverse events constantly remain a great challenge. Regular periodic clinical evaluation of patients with pemphigus on steroids is mandatory. This article describes a case of a 50-year-old woman with multiple chronic ulcers in the oral cavity in whom the diagnosis of PV was made and treated. The case study is followed by a review of the literature including etiology, pathogenesis, clinical features, as well as the various diagnostic criteria and the therapeutic options of PV.

The role of oral microbiome in pemphigus vulgaris

While the impact of oral microbiome dysbiosis on autoimmune diseases has been partially investigated, its role on bullous diseases like Pemphigus Vulgaris (PV) is a totally unexplored field. This study aims to present the composition and relative abundance of microbial communities in both healthy individuals and patients with oral PV lesions. Ion Torrent was used to apply deep sequencing of the bacterial 16S rRNA gene to oral smear samples of 15 healthy subjects and 15 patients. The results showed that the most dominant phyla were Firmicutes (55.88% controls-c vs 61.27% patients-p, p value = 0.002), Proteobacteria (9.17%c vs 12.33%p, p value = 0.007) and Fusobacteria (3.39%c vs 4.09%p, p value = 0.03). Alpha diversity showed a significant difference in the number of genera between patients and controls (p value = 0.04). Beta diversity showed statistical differences in the microbial community composition between two groups. Fusobacterium nucleatum, Gemella haemolysans and Parvimonas micra were statistically abundant in patients. We noticed the characteristic fetor coming out of oral PV lesions. Most of anaerobic bacteria responsible for oral halitosis are periopathogenic. Though, only F. nucleatum and P. micra were differentially abundant in our patients. Especially, F. nucleatum has been reported many times as responsible for bad breath. Furthermore, Streptococcus salivarius and Rothia mucilaginosa, species mostly associated with clean breath, were found in relative abundance in the healthy group. Consequently, the distinct malodor observed in PV patients might be attributed either to the abundance of F. nucleatum and P. micra and/or to the lower levels of S. salivarius and R. mucilanginosa in oral lesions.

Single-cell membrane drug delivery using porous pen nanodeposition

Delivering molecules onto the plasma membrane of single cells is still a challenging task in profiling cell signaling pathways with single cell resolution. We demonstrated that a large quantity of molecules could be targeted and released onto the membrane of individual cells to trigger signaling responses. This is achieved by a porous pen nanodeposition (PPN) method, in which a multilayer porous structure, serving as a reservoir for a large amount of molecules, is formed on an atomic force microscope (AFM) tip using layer-by-layer assembly and post processing. To demonstrate its capability for single cell membrane drug delivery, PPN was employed to induce a calcium flux triggered by the binding of released antibodies to membrane antigens in an autoimmune skin disease model. This calcium signal propagates from the target cell to its neighbors in a matter of seconds, proving the theory of intercellular communication through cell-cell junctions. Collectively, these results demonstrated the effectiveness of PPN in membrane drug delivery for single cells; to the best of our knowledge, this is the first technique that can perform the targeted transport and delivery in single cell resolution, paving the way for probing complex signaling interactions in multicellular settings.

Pemphigus with features of both vulgaris and foliaceus variants localized to the nose

We report the case of a 74-year-old man affected by an unusual variant of pemphigus. He presented with a crusty and scaly lesion of the nose. We performed reflectance confocal microscopy and optical coherence tomography on the lesion, which suggested an unexpected diagnosis of pemphigus. Therefore, to confirm our diagnostic suspicions, we executed indirect immunofluorescence and two biopsies, one for histopathological examination and one for direct immunofluorescence. Histopathological evaluation showed acantholysis with formation of clefts in the granular and spinous layers of the epidermis. Direct immunofluorescence revealed immunoglobulin G and C3 deposit to the full thickness of the epidermis. Indirect immunofluorescence showed intercellular antibodies at a titer of 1:40 in the suprabasal epidermis. The immunoblot analysis using epidermal extract revealed the presence of circulating antibodies directed to 130- and 160-kDa antigens in the patient's serum. These two antigens were evidenced from nitrocellulose membrane with colorimetric AP systems, which highlighted the presence of autoantibodies against desmoglein (Dsg)1 and Dsg3 (sodium dodecylsulfate polyacrylamide gel electrophoresis). We also performed an enzyme-linked immunoassay. All these findings suggested that this patient's pemphigus had features of both vulgaris and foliaceus variants.

An Overview of Vesicobullous Conditions Affecting the Oral Mucosa

Vesicobullous diseases are characterised by the presence of vesicles or bullae at varying locations in the mucosa. The most common occurring in the oral cavity are mucous membrane pemphigoid (MMP) and pemphigus vulgaris (PV). Both are autoimmune diseases with a peak age onset of over 60 years and females are more commonly affected than men. This paper reviews the structure of the oral mucosa, with specific reference to the basement membrane zone, as well as bullous conditions affecting the mucosa, including PV and pemphigoid, their aetiology, clinical presentation, and management.

Tumor necrosis factor (TNF)-α -308G/A (rs1800629) polymorphism distribution in North India and its association with pemphigus: Case-control study and meta-analysis

Pemphigus is an autoimmune blistering disorder of skin and/or mucosal surfaces characterized by intraepithelial lesions and immunoglobulin-G autoantibodies against desmogleins (proteins critical in cell-to-cell adhesion). Genetic, immunological, hormonal, and environmental factors are known to contribute to its etiology. Tumor necrosis factor-alpha (TNF-α) which plays a key role in pathogenesis of many infectious and inflammatory diseases has been found in high levels in lesional skin and sera of pemphigus patients. However, studies on association of single nucleotide polymorphism (SNP) in promoter region of TNF-α at position -308 affecting G to A transition with pemphigus has been scarce. This study was conducted to evaluate the TNF-α -308G/A SNP distribution in North Indian cohort, and to define the association between the TNF-α -308G/A SNP distribution and pemphigus, globally, by means of meta-analysis. TNF-α -308G/A SNP in pemphigus patients was investigated by cytokine genotyping using genomic DNA by PCR with sequence-specific primers. Meta-analysis of the data, including four previously published studies from other populations, was performed to generate a meaningful relationship. The results of our case-control study indicate non-significant differences between patients and controls in TNF-α -308G/A SNP. The meta-analysis also revealed that TNF-α -308G/A SNP is not associated with pemphigus risk in population at large; however, it may be contributing towards autoimmune phenomenon in pemphigus by being a part of its multi-factorial etiology. This study provides evidence that the TNF-α -308G/A polymorphism is not associated with overall pemphigus susceptibility. Nevertheless, further studies on specific ethnicity and pemphigus variants are necessary to validate the findings.

Oral Lesions: The Clue to Diagnosis of Pemphigus Vulgaris

Pemphigus is a group of potentially fatal dermatoses with both cutaneous and oral manifestations. Characterized by the appearance of vesicle or bullae, their manifestations in the oral cavity often precede those on the skin by many months or may remain as the only symptoms of the disease. It is therefore important that the oral manifestations of the disease are recognized on time, to make a proper diagnosis and initiate timely treatment. Here we present a case of Pemphigus Vulgaris (PV) that presented with oral lesions at multiple sites including tongue, to highlight the importance of timely recognition of the oral lesions during routine dental practice for the diagnosis and management of this disease.

Prediction of survival for patients with pemphigus vulgaris and pemphigus foliaceus: a retrospective cohort study

Background

Factors associated with survival in pemphigus have not yet been thoroughly addressed. Therefore, in the present study, risk factors for overall mortality in a large group of patients with pemphigus vulgaris and foliaceus were investigated.

Methods

A retrospective hospital-based cohort study was carried out, between October 1998 and November 2012, in the Department of Dermatology of the University of Medicine and Pharmacy “Iuliu Hatieganu”, Cluj-Napoca, Romania. The investigated prognostic endpoint was the overall survival of the patients.

Results

A total of 130 patients were studied (108 with pemphigus vulgaris and 22 with pemphigus foliaceus). In pemphigus vulgaris group, univariate analysis found a statistically significant association between the age of onset ≥ 65 years (p < 0.001), presence of coronary heart disease (p = 0.006), presence of cardiac arrhythmia (p = 0.004), level of anti-desmoglein1 autoantibodies ≥ 100 U/mL (p = 0.047) at diagnosis and the survival of the patients. An age-adjusted analysis showed significant results for coronary heart disease. Multivariate analysis identified the age of onset ≥ 65 years and the presence of coronary heart disease at diagnosis as independent risk factors associated with overall mortality. In patients with pemphigus foliaceus, age of onset ≥ 65 years (p = 0.021) was associated with poor survival.

Conclusions

In addition to common prognostic factors, including older age and cardiovascular comorbidities, level of autoantibodies was found to be a disease-specific factor associated with overall mortality in pemphigus vulgaris. The newly identified factors have major implications for the stratification of patients and should greatly facilitate further epidemiological studies in pemphigus. In addition, they provide useful information for the design of personalized therapeutic plans in the clinical setting.

Non-classical forms of pemphigus: pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus and IgG/IgA pemphigus

The pemphigus group comprises the autoimmune intraepidermal blistering diseases classically divided into two major types: pemphigus vulgaris and pemphigus foliaceous. Pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus and IgG/IgA pemphigus are rarer forms that present some clinical, histological and immunopathological characteristics that are different from the classical types. These are reviewed in this article. Future research may help definitively to locate the position of these forms in the pemphigus group, especially with regard to pemphigus herpetiformis and the IgG/ IgA pemphigus.

Peripheral T-cell lymphoma complicated by immunoglobulin A pemphigus: A case report and literature review

Peripheral T-cell lymphomas (PTCLs) account for 12% of non-Hodgkin's lymphomas (NHLs). Immunoglobulin (Ig) A pemphigus is an autoimmune blistering disease characterized by tissue-bound and circulating IgA antibodies that target epidermal cell surface components. Malignant lymphomas are often linked with autoimmune disease and the autoimmune blistering disease, paraneoplastic pemphigus, has been associated with NHL. However, cases of PTCLs that are complicated by IgA pemphigus are particularly rare. The current study presents the first known case of PTCL complicated by IgA pemphigus. A 43-year-old male was admitted to the Union Hospital (Wuhan, China) in March 2012 with multiple swollen lymph nodes. Pathology examinations revealed PTCL. Immunohistochemical staining was positive for cluster of differentiation (CD)2, CD3, CD5, CD7 and CD47, and negative for CD20. Ki-67 was ~40% positive. The patient was treated with four cycles of cyclophosphamide, Adriamycin, vincristine and prednisone, and two cycles of gemcitabine, cisplatin and dexamethasone; in addition, the patient received radiation of the retroperitoneal region (total dose, 36 Gy). The patient underwent thalidomide maintenance therapy for 20 days before flaccid blisters appeared on the trunk and limbs. Histopathology and immunofluorescence indicated IgA pemphigus, and intravenous methylprednisolone was administered, followed by treatment with prednisone. Subsequently, no evidence of recurrent lymphoma or pemphigus has been observed.

p38 MAPK Signaling in Pemphigus: Implications for Skin Autoimmunity

p38 mitogen activated protein kinase (p38 MAPK) signaling plays a major role in the modulation of immune-mediated inflammatory responses and therefore has been linked with several autoimmune diseases. The extent of the involvement of p38 MAPK in the pathogenesis of autoimmune blistering diseases has started to emerge, but whether it pays a critical role is a matter of debate. The activity of p38 MAPK has been studied in great detail during the loss of keratinocyte cell-cell adhesions and the development of pemphigus vulgaris (PV) and pemphigus foliaceus (PF). These diseases are characterised by autoantibodies targeting desmogleins (Dsg). Whether autoantibody-antigen interactions can trigger signaling pathways (such as p38 MAPK) that are tightly linked to the secretion of inflammatory mediators which may perpetuate inflammation and tissue damage in pemphigus remains unclear. Yet, the ability of p38 MAPK inhibitors to block activation of the proapoptotic proteinase caspase-3 suggests that the induction of apoptosis may be a consequence of p38 MAPK activation during acantholysis in PV. This review discusses the current evidence for the role of p38 MAPK in the pathogenesis of pemphigus. We will also present data relating to the targeting of these cascades as a means of therapeutic intervention.

Molecular diagnosis of autoimmune blistering diseases

Autoimmune bullous diseases are the best-characterized autoimmune skin diseases. Molecular diagnosis of these diseases has become possible due to the identification of their target autoantigens over the past three decades. In this review, we summarize methodology for categorizing autoimmune bullous diseases by means of combinations of direct and indirect immunofluorescence techniques using normal human skin sections, rat bladder sections and COS7 cells transfected with desmocollins 1-3 encoded vectors, enzyme-linked immunosorbent assays and immunoblotting with normal human epidermal extracts, dermal extracts, purified proteins from cell cultures and recombinant proteins.

Cytokine networks in Pemphigus vulgaris: An integrated viewpoint

Pemphigus vulgaris (PV) is an autoimmune bullous skin disease where tolerance to the desmosomal protein desmoglein 3 (Dsg3), and perhaps additional epidermal targets, is lost, leading to the production of autoantibodies directed against cellular adhesion molecules. As auto-reactive T cells are involved in the induction and maintenance of antibody production, it has been hypothesized that cytokines play a crucial role in disease pathogenesis. Qualitative and quantitative alterations in cytokine profiles have been previously reported; however, despite recent advancements, the characterization of the disease supporting cytokine network in PV has yet to be fully elucidated. It is overwhelmingly suggested that PV is a TH2-mediated disease, confirmed by the majority of studies demonstrating an increase in TH2-type cytokines. Recently, a focus has been placed on the contribution of the newly discovered TH17 subset to autoimmune states, and current evidence suggests that this inflammatory pathway may play a role in PV as well. Anti-cytokine medications are on the forefront as potential therapeutic options, and the growing number of reports of clinical benefit serves to confirm the major contribution of various inflammatory mediators in the development of disease phenotype. This work aimed to comprehend the complexity of cytokine and T cell involvement in pemphigus, taking account of known information and emphasizing the areas where additional research would be of great benefit, particularly in pharmacological development and expansion of the pemphigus therapeutic armamentarium.

Tumor necrosis factor-α -308 G>A and interleukin-6 -174 G>C promoter polymorphisms and pemphigus

The objective of this study was to analyze the possible involvement of the tumor necrosis factor (TNF)-α -308 G>A and interleukin-6 (IL-6) -174 G>C polymorphisms in the susceptibility and/or disease profile of pemphigus in Egyptian patients. Detection of TNF-α -308 G>A by amplification refractory mutation system and IL-6 -174 G>C by restriction fragment length polymorphism was performed for 70 patients and 203 controls. No significant differences were observed in the distribution of TNF-α -308 in pemphigus patients and controls. However, GA+AA genotypes were more frequent in pemphigus vulgaris (PV) patients only versus controls (p(c) = 0.046). The frequency of the C allele and CC/GC genotypes of IL-6 -174 was significantly higher in pemphigus patients and those with the 2 major clinical forms (PV and pemphigus foliaceus [PF]) compared with controls (p < 0.05). Comparison of the distribution of TNF-α -308 and IL-6 -174 variants in relation to clinical type of pemphigus (PV versus PF), activity score, recurrence, and demographic data of patients revealed no significant associations. The IL-6 -174 CC genotype represents a marker of increased susceptibility to pemphigus in Egyptian patients and GG genotype can be considered a low-risk genotype; TNF-α -308 A-containing genotypes contribute to the susceptibility to PV only.

Severe manifestation of oral pemphigus

This article describes a case of pemphigus vulgaris in a relatively young patient with exacerbated characteristics, widespread lesions, and rapid evolution. A 40-year-old woman sought treatment, complaining about severe oral pain and dysphagia. Intraoral inspection revealed ulcerated lesions on the lips, buccal mucosa, and floor of the mouth. The number of lesions quickly increased and resembled erythema multiforme. She also presented blistering lesions on the back, abdomen, neck, and eyes. Incisional oral biopsy revealed pemphigus vulgaris. This report emphasizes the importance of early diagnosis of an oral biopsy in systemic diseases and the management of the lesions.

Hypertrophic osteopathy secondary to pulmonary sarcoma in a cat

A case of hypertrophic osteopathy secondary to a pulmonary spindle cell sarcoma is described. The 9-year-old male cat presented with a 1-month history of decreased appetite, decreased activity and progressive lameness with swelling and pain of all four limbs. Thoracic radiographs showed a soft tissue opaque mass in the left caudal lung lobe. Radiographs of all limbs showed extensive periosteal new bone formation of uniform opacity demonstrating a 'palisading' pattern. The lung mass was removed at exploratory thoracotomy; histopathological examination diagnosed a low-grade spindle cell sarcoma. Prior to surgery, the cat had a non-specific conjunctivitis that resolved spontaneously following lobectomy raising the possibility of a paraneoplastic association. The lameness also resolved; six months after surgery, the periosteal palisading of new bone on the long bones had remodelled, and there was no evidence of pulmonary metastases.

Paraneoplastic autoimmune multiorgan syndrome: Review of the literature and support for a cytotoxic role in pathogenesis

Paraneoplastic autoimmune multiorgan syndrome (PAMS), first described as paraneoplastic pemphigus in 1990, is an autoimmune blistering disease associated with neoplasia. Patients with this rare disorder have severe blistering and painful erosions of the oral cavity and various other cutaneous findings ranging from classic pemphigus vulgaris-like erosions to targetoid lesions resembling erythema multiforme and papular to more confluent lichenoid eruptions. This syndrome involves multiple organ systems, and its high rate of mortality often stems from constrictive bronchiolitis obliterans. The histologic findings are as diverse as the clinical presentation, often making diagnosis difficult initially. Immunodermatologic and serologic laboratory findings typically establish the diagnosis. These results can be confirmed with immunoprecipitation profiling of specific molecular weight protein markers. The proposed pathogenesis of PAMS continues to evolve, and recent reports implicate the involvement of cell-mediated, cytotoxic immunity, in addition to humoral autoantibodies. This review characterizes and summarizes the clinical, pathologic, and immunohistologic features of PAMS and outlines the possible role of cytotoxic T lymphocytes in the pathogenesis of this syndrome.

The role of T cells in cutaneous autoimmune disease

T cells assume a fundamental function in immunosurveillance and maintenance of the cutaneous immune barrier, yet derangement of their requisite role effects a range of cutaneous autoimmune diseases with significant associated morbidity. While blistering skin diseases, such as pemphigus vulgaris (PV), pemphigus foliaceus (PF) and bullous pemphigoid (BP) are mediated by antibodies directed against autoantigens found in the skin, recent evidence has shown that T cell activation is crucial for the initiation and coordination of this humoral response. Non-blistering skin diseases, such as alopecia areata (AA), vitiligo (VL) and psoriasis (PS) are increasingly believed to be directly mediated by the activities of autoreactive T cells. Here, we examine T lymphocyte control of antibody-mediated and cell-mediated processes involved in the pathoimmunology of the above mentioned skin diseases.

The desmosome and pemphigus

Desmosomes are patch-like intercellular adhering junctions ("maculae adherentes"), which, in concert with the related adherens junctions, provide the mechanical strength to intercellular adhesion. Therefore, it is not surprising that desmosomes are abundant in tissues subjected to significant mechanical stress such as stratified epithelia and myocardium. Desmosomal adhesion is based on the Ca(2+)-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules. Desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families. Desmosomes are dynamic structures subjected to regulation and are therefore targets of signalling pathways, which control their molecular composition and adhesive properties. Moreover, evidence is emerging that desmosomal components themselves take part in outside-in signalling under physiologic and pathologic conditions. Disturbed desmosomal adhesion contributes to the pathogenesis of a number of diseases such as pemphigus, which is caused by autoantibodies against desmosomal cadherins. Beside pemphigus, desmosome-associated diseases are caused by other mechanisms such as genetic defects or bacterial toxins. Because most of these diseases affect the skin, desmosomes are interesting not only for cell biologists who are inspired by their complex structure and molecular composition, but also for clinical physicians who are confronted with patients suffering from severe blistering skin diseases such as pemphigus. To develop disease-specific therapeutic approaches, more insights into the molecular composition and regulation of desmosomes are required.

Immunopathology and molecular diagnosis of autoimmune bullous diseases

Autoimmune bullous diseases are associated with autoimmunity against structural components maintaining cell-cell and cell matrix adhesion in the skin and mucous membranes. Pemphigus diseases are characterized by autoantibodies against the intercellular junctions and intraepithelial blisters. In pemphigoid diseases and epidermolysis bullosa acquisita, sub-epidermal blistering is associated with autoantibodies targeting proteins of the hemidesmosomal anchoring complex. The autoantigens in autoimmune blistering diseases have been extensively characterized over the past three decades. In general, the pathogenicity of autoantibodies, already suggested by clinical observations, has been conclusively demonstrated experimentally. Detection of tissue-bound and circulating serum autoantibodies and characterization of their molecular specificity is mandatory for the diagnosis of autoimmune blistering diseases. For this purpose, various immunofluorescence methods as well as immunoassays, including immunoblotting, enzyme-linked immunosorbent assay and immunoprecipitation have been developed. This review article describes the immunopathological features of autoimmune bullous diseases and the immunological and molecular tests used for their diagnosis and monitoring.

Generalized erythrodermic pemphigus foliaceus in a child and its successful response to rituximab treatment

Pemphigus foliaceus is an autoimmune disease that clinically manifests with cutaneous blisters of the superficial skin. The nonendemic or sporadic form of this entity is rare in children and typically presents with a milder, more localized rash that usually follows a benign course of short duration. We describe an affected patient atypical in both her young age and the severity of skin findings. Our patient presented with a full body exfoliative erythroderma at 21 months of age. After an extensive work-up to determine the etiology of her exfoliative erythroderma, direct and indirect immunofluorescence studies confirmed the diagnosis of pemphigus foliaceus. Rituximab therapy was initiated based on the patient's refractory disease course to multiple immunosuppressive agents. Rituximab is a therapeutic monoclonal antibody targeting CD20, an integral membrane protein highly expressed on the surface of pre-B lymphocytes and activated mature B lymphocytes. The patient's skin exhibited marked clinical improvement after the start of rituximab infusions over 12 weeks. Her initial desmoglein 1 antibody level was greater than 1:1280, which decreased to 1:16 after seven rituximab treatments. She has had no skin flares since initiating treatment with rituximab therapy. Based on this clinical and serologic response, the use of rituximab may be helpful in the treatment of pediatric pemphigus foliaceus refractory to mainstays of therapy.

Immunohistochemical analysis of the distribution of desmoglein 1 and 2 in the skin of dogs and cats

OBJECTIVE

To compare the distribution of desmoglein (Dsg) 1 and 2 in skin specimens obtained from dogs and cats to provide information about the possible role of the density of Dsg 1 and 2 in the localization of lesions attributable to pemphigus foliaceus in these 2 species.

SAMPLE POPULATION

Skin biopsy specimens obtained from 4 dogs and 4 cats.

PROCEDURE

Biopsy specimens were collected from the muzzle, bridge of the nose, ear, dorsum, abdomen, area adjacent to the teats, and footpads of each animal. Immunohistochemical analysis was performed on formalin-fixed, paraffin-embedded skin samples by use of a biotinylated mouse monoclonal anti-Dsg 1 and 2 antibody raised against bovine muzzle. Color development was performed by use of the streptavidin-biotin-peroxidase method with a chromogenic substrate.

RESULTS

Immunohistochemical staining yielded a positive reaction in skin samples obtained from all anatomic sites. The intensity and distribution of staining were related to the number of layers of the stratum spinosum. No differences were detected between samples obtained from dogs and cats.

CONCLUSIONS AND CLINICAL RELEVANCE

No differences in intensity of Dsg 1 and 2 antigen were observed in the stratum spinosum between skin samples obtained from dogs and cats. Analysis of this result suggests that factors other than the distribution of Dsg may be responsible for the differences in localization of primary clinical lesions in dogs and cats with pemphigus foliaceus.

Treatment of pemphigus vulgaris. An overview in Mexico

Pemphigus is an autoimmune skin disease that can present in a variety of forms and can prove challenging to manage and treat. An overview of the condition in Mexico is presented. Emphasis is placed on management of the condition, with description of the most commonly used treatments (glucocorticoids, azathioprine), the second line therapies (cyclosporine and mycophenolate mofetil), and additional alternative treatments (cyclophosphamide and dapsone).

Pemphigus foliaceus IgG causes dissociation of desmoglein 1-containing junctions without blocking desmoglein 1 transinteraction

Autoantibodies against the epidermal desmosomal cadherins desmoglein 1 (Dsg1) and Dsg3 have been shown to cause severe to lethal skin blistering clinically defined as pemphigus foliaceus (PF) and pemphigus vulgaris (PV). It is unknown whether antibody-induced dissociation of keratinocytes is caused by direct inhibition of Dsg1 transinteraction or by secondary cellular responses. Here we show in an in vitro system that IgGs purified from PF patient sera caused cellular dissociation of cultured human keratinocytes as well as significant release of Dsg1-coated microbeads attached to Dsg-containing sites on the keratinocyte cellular surface. However, cell dissociation and bead release induced by PF-IgGs was not caused by direct steric hindrance of Dsg1 transinteraction, as demonstrated by single molecule atomic force measurements and by laser trapping of surface-bound Dsg1-coated microbeads. Rather, our experiments strongly indicate that PF-IgG-mediated dissociation events must involve autoantibody-triggered cellular signaling pathways, resulting in destabilization of Dsg1-based adhesive sites and desmosomes.

Direct characterization of human T cells in pemphigus vulgaris reveals elevated autoantigen-specific Th2 activity in association with active disease

Pemphigus vulgaris (PV) is a blistering skin disorder mediated by autoantibodies targeting the epidermal adhesion molecule desmoglein 3 (Dsg3). As Th2-associated cytokines are necessary for directing antibody production, it is hypothesized that Dsg3-specific Th2 activity is associated with active disease. We used cell-surface-matrix technology in combination with flow cytometry to characterize the Dsg3-reactive T-cell population using peripheral blood mononucleocytes sampled from PV patients stratified by active (n = 9) or remittent disease (n = 6), and healthy human leucocyte antigen-matched controls (n = 5). We evaluated interferon-gamma-producing CD4+ cells (Th1) and interleukin (IL)-10- or IL-4-producing CD4+ cells (Th2). The mean frequency of Th2 CD4+ T cells was significantly elevated for five of nine PV patients with active disease. No significant Th2 responses were detected for patients with remittent disease or controls. There was a significant association of Th2 activity with active disease compared with remittent and control groups (P = 0.026 and P =0.012, respectively), and Th2 activity was significantly correlated with anti-Dsg3 IgG titre (P = 0.044). One patient with remittent disease converted from a Th2-negative to a Th2-positive response with the initiation of disease activity. An antigen-specific CD4- lymphocyte response was detected in five PV patients (36%), and was shown to correlate closely with the CD8+ population. These results are consistent with the hypothesis that Th2 response directs autoantibody production and is therefore associated with disease activity in PV.