Thalidomide Alleviates Apoptosis, Oxidative Damage and Inflammation Induced by Pemphigus Vulgaris IgG in HaCat Cells and Neonatal Mice Through MyD88

Purpose

Thalidomide (Tha) can be used as a selective treatment for mild pemphigus vulgaris (PV). However, the specific mechanism of action remains unclear.

Patients and Methods

PV IgG extracted from patients' serum was cocultured with HaCaT cells to construct a PV cell model, and different concentrations of Tha were used to screen the drug effect. The expression level of MYD88 was assessed in skin lesions of PV patients. Intracellular Ca2+ concentration, reactive oxygen species level, DSG3, PG, MYD88, apoptosis-related proteins (Caspase-3, Bcl-2, and Bax), NF-κB pathway-related proteins (IκBα, p-IκBα, p50, and p65), NLRP3, IFN-γ, TNF-α, IL-6, and IL-8 levels were measured. PV IgG was subcutaneously injected into C57BL/6 neonatal mice to construct the animal model. Immunofluorescence was used to detect IgG deposition in the mouse epidermis, whereas immunohistochemistry and TUNEL methods were used to detect the expression of MYD88 and NLRP3 as well as cell apoptosis level in the mouse epidermis.

Results

Tha reversed the decrease in Dsg3 and PG caused by PV IgG. The expression of MyD88 increased in the patients' skin, PV cell model, and PV mouse model. The increase in MyD88 expression level in PV cell models and PV newborn mouse models was inhibited by Tha. Overexpression of MyD88 induced a decrease in the expression levels of Dsg3 and PG in Hacat cells. Overexpression of MyD88 inhibited Tha effects on Dsg3 and PG expressions and blocked Tha effects on Ca2+, apoptosis, Bax, Bcl-2, and Caspase-3 expressions, oxidative damage, and inflammatory response in HaCat cells. Tha alleviated acantholysis induced by PV IgG in model mice.

Conclusion

Through MYD88, Tha attenuated apoptosis of HaCat cells, modulated NF-κB to hamper the oxidative damage and inflammatory response in the PV cell models, and alleviated acantholysis, IgG deposition, and epidermal cell apoptosis induced by PV IgG in model mice.

Blocking soluble Fas Ligand ameliorates pemphigus: PC111 efficacy in ex-vivo human pemphigus models

Pemphigus is a life-threatening, chronic, autoimmune bullous disease affecting both the skin and the mucous membranes. Based on the mainstream concept that blister formation occurs upon binding of autoantibodies to their antigen proteins (desmoglein1, DSG1 and desmoglein3, DSG3), current therapies mostly aim to suppress the immune system. To avoid the severe side effects associated with the chronic use of immunosuppressive treatments, we have developed PC111, a fully human monoclonal antibody targeting human Fas ligand (FasL). We have provided a number of in vitro and in vivo evidences showing that soluble FasL induces keratinocyte apoptosis followed by acantholysis. An anti-murine FasL prevents blister formation in the pemphigus neonatal mouse model. To confirm the mechanism of action (MoA) and the efficacy of PC111 in a human pemphigus context, we used the keratinocyte dissociation assay and two independent Human Skin Organ Cultures (HSOC) pemphigus models. PC111 reduced acantholysis in vitro, as shown by the dose-dependent reduction of fragments in the monolayer cultures. In the first HSOC model, normal human skin was subcutaneously injected with a scFv antibody fragment directed against DSG1 and DSG3, resulting in a severe acantholysis (70-100%) after 24 hours. PC111 inhibited blister formation to around 50% of control. In the second model, normal human skin was injected with a mixture of pemphigus patients' autoantibodies resulting in a less severe acantholysis (20-30%). PC111 significantly suppressed blister formation to more than 75% up to 72 hours. These results confirm PC111 MoA and demonstrates the efficacy of the anti-FasL antibody also in a pemphigus setting.

In Vitro, Ex Vivo, and In Vivo Models for the Study of Pemphigus

Pemphigus is a life-threatening autoimmune disease. Several phenotypic variants are part of this family of bullous disorders. The disease is mainly mediated by pathogenic autoantibodies, but is also directed against two desmosomal adhesion proteins, desmoglein 1 (DSG1) and 3 (DSG3), which are expressed in the skin and mucosae. By binding to their antigens, autoantibodies induce the separation of keratinocytes, in a process known as acantholysis. The two main Pemphigus variants are Pemphigus vulgaris and foliaceus. Several models of Pemphigus have been described: in vitro, ex vivo and in vivo, passive or active mouse models. Although no model is ideal, different models display specific characteristics that are useful for testing different hypotheses regarding the initiation of Pemphigus, or to evaluate the efficacy of experimental therapies. Different disease models also allow us to evaluate the pathogenicity of specific Pemphigus autoantibodies, or to investigate the role of previously not described autoantigens. The aim of this review is to provide an overview of Pemphigus disease models, with the main focus being on active models and their potential to reproduce different disease subgroups, based on the involvement of different autoantigens.

Anti-Desmocollin Autoantibodies in Autoimmune Blistering Diseases

The presence of anti-desmocollin (Dsc) antibodies is rarely described in autoimmune blistering diseases patients. Moreover, several clinical phenotypes of pemphigus may be associated with these antibodies. In this review we analyze clinicopathological, immunologic and outcome features of anti-Dsc autoimmune blistering diseases patients, to improve their diagnosis and management. We conducted a systematic search of PubMed and Embase (1990-present) for studies reporting cases of autoimmune blistering diseases with anti-Dsc antibodies. We classified the selected patients as patients with exclusively anti-Dsc autoantibodies, and patients with anti-Dsc and other autoantibodies. Of 93 cases with anti-Dsc autoantibodies included, 38 (41%) had exclusively these antibodies. Only 18% of patients presented with the typical clinicopathological phenotype of pemphigus vulgaris or pemphigus foliaceous. Mucosal involvement was seen in approximately half of the patients. Up to 18% of cases were associated with neoplasms. Acantholysis was described in 54% of cases with histopathological information. Treatments and outcomes vary in the different clinical phenotypes. The presence of anti-Dsc antibodies must be suspected mainly in those patients with either atypical pemphigus, in special with clinical pustules, or in cases showing intraepithelial or dermal neutrophilic/eosinophilic infiltrate on histological examination and dual pattern by direct immunofluorescence examination.

An unusual case of annular bollous eruption of the inguinal folds

Pemphigus herpetiformis is a rare clinical entity belonging to the group of autoimmune blistering disorders of the skin, that usually presents clinical features of dermatitis herpetiformis and immunologically findings of pemphigus. Because of the variety of its presentation, differential diagnosis with other bollous diseases is not simple and histopathological results have to be supported by direct immunofluorescence assay, for a correct diagnosis. We report the case of a young woman, where immunofluorescence was a fundamental tool to reach the diagnosis of pemphigus herpetiformis, because of the lack of acantholitic cells at histological sample.

A novel method to investigate pemphigus-induced keratinocyte dysmorphisms through living cell immunofluorescence microscopy

Pemphigus vulgaris (PV) blistering occurs as a result of the disruption of intercellular contacts among keratinocytes, or acantholysis. The hallmark of PV acantholysis in vitro is considered to be the retraction of keratin intermediate filaments (KIF) onto the nucleus, which parallels with loss of cell-cell adhesion and rounding up of keratinocytes. However, the fine morphological changes of keratinocytes as well as the fate of cell adhesion structures cannot be appreciated on immunofluorescence by the simple cytokeratin staining. In this paper, we show that acantholytic dysmorphisms are sharply investigated by using PV IgG as a primary antibody on metabolically quiescent living cells. Indeed, PV IgG recognise a wide spectrum of molecules and enabled us to monitor the main changes occurring in acantholytic keratinocytes, including cell shrinkage with the appearance of prickle-like processes, detachment of keratinocytes from one another and collapse of cytoskeleton-bound proteins along nuclear periphery. This method has wider applications as it could be useful for staining cell periphery of keratinocytes and changes in cell shape. Furthermore, images displayed clear and sharp contours because living cell microscopy allows to avoid antigen distortion due to cell manipulation, which usually precedes the immunolabelling.

Vulvar Acantholytic Squamous Carcinoma: A Case Report With Immunohistochemical and Molecular Study

Acantholytic carcinoma is a subtype of squamous carcinoma, characterized by tubular and alveolar formations as a consequence of the acantholysis. We report a case of vulvar squamous acantholytic carcinoma (VSAC) in a 69-year-old woman, who was admitted to our institution for vulvar pruritus and the presence of a large, bilateral, exophytic, and ulcerated lesion, measuring 7 x 8 cm. The patient had never received vulvar or pelvic radiation therapy. Pathological examination with an immunohistochemical study showed features of VSAC and high p16 protein expression. Molecular study by polymerase chain reaction amplification of DNA tumor revealed a weakly positive signal for human papillomavirus. In conclusion, our case, which is the first case of VSAC with polymerase chain reaction analysis and immunohistochemical expression of p16 protein, suggested that this neoplasm could be related to human papillomavirus infection.

Immunohistochemical and cytogenetic characterization of acantholytic squamous cell carcinoma of the breast

Primary acantholytic squamous cell carcinoma (ASCC) of the breast is a rare and aggressive variant of invasive breast cancer. Here we report two new cases of ASCC and their immunohistochemical and cytogenetic characterization. One case was associated with systemic metastases and death and the other with local failure prior to loss of follow-up. Using comparative genomic hybridization (CGH), both tumors showed a high overall number of chromosomal imbalances with a similar pattern of gains and losses. Genetic aberrations common to both tumors included losses at 3p11-p25, 5q21-q31, 8p, 9, 13p13-q21, 16q12-q21, and 17p and gains at 1q31-qter, 7p, 18q12-qter, 19q, and 20. Immunohistochemically, the tumors were characterized by high proliferative activity, an uncommon cytokeratin expression profile, reduced E-cadherin staining, and overexpression of p53 and epithelial growth factor receptor (EGFR). The results of our analyses suggest that genetic alterations observed in ASCC of the breast include imbalances commonly observed in both mammary adenocarcinoma and squamous cell carcinoma of other locations. Furthermore, the overexpressed EGFR could be a possible therapeutic target for individual cases of this aggressive tumor type.

Pemphigus foliaceus with neutrophilic spongiosis evolving to an atypical pemphigus phenotype

A 46-year-old Brazilian man, with initial pustular lesions, neutrophilic spongiosis and subcorneal cleavage evolved to an atypical pemphigus phenotype, with suprabasal acantholysis. Interestingly, his autoantibody profile, tested by immunofluorescence, immunoblotting, enzyme-linked immunosorbent assay, and immunoprecipitation revealed exclusive IgG anti-desmoglein 1 antibodies in all phases of the disease.

Clinicopathologic attributes of common geriatric dermatologic entities

Certain dermatologic lesions may initially present or be more commonly ascribed to the elderly. These disorders encompass a diverse array of etiologically unrelated degenerative, autoimmune, idiopathic, and neoplastic conditions that may dramatically impact the quality of life and produce significant morbidity and mortality. As the population ages, a more complete understanding of the clinical and histopathologic features unique to the geriatric dermatologic patient is essential.

Diagnosing Pemphigus foliaceus: a retrospective analysis of clinical, histological and immunological criteria

BACKGROUND

Clinical, histological and immunological criteria distinguish pemphigus foliaceus (PF) from pemphigus vulgaris (PV), but whether and how often they are concordant in the same patient is unknown.

METHODS

Seven clinical records were selected from two hospital settings for having a diagnosis of PF and the initial serum and histopathological specimens still available. Controls were 8 PV records selected in the same way. Histopathological slides were re-evaluated. Stored sera were studied by indirect immunofluorescence (IIF), Western blot and ELISA.

RESULTS

Acantholysis was superficial in all PF patients and deep in all PV patients. Mucosal lesions were not exclusive of PV. IIF was positive in 43% of PF patients. Western blot revealed desmoglein 1 in 86% of PF patients and in 25% of PV. ELISA revealed anti-desmoglein-1 antibodies in up to 71% of PF and in 62% of PV patients, in 1 failing to detect anti-desmoglein-3 antibodies.

CONCLUSIONS

Histopathology remains the most reliable criterion for diagnosing PF. Western blot and ELISA, especially in combination, may be only of confirmatory value.

Zosteriform Darier's disease versus acantholytic dyskeratotic epidermal nevus

Patients with keratotic lesions distributed in a unilateral, linear, zosteriform or localized pattern and revealing histologic features of dyskeratotic acantholysis have been reported. There is still some controversy regarding the appropriate nosologic placement of this entity. Some believe it represents a localized form of Darier s disease, while others argue it is a variant of epidermal nevus. We report a case of a 42-year-old physician who presented with a 15-year history of an asymptomatic eruption that had been diagnosed as "chronic zoster." Physical exam revealed hyperkeratotic papules and plaques in a dermatomal distribution. The controversy regarding the correct nosologic placement of such a patient is discussed.

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.

In vitro and in vivo expression of interleukin-1alpha and tumor necrosis factor-alpha mRNA in pemphigus vulgaris: interleukin-1alpha and tumor necrosis factor-alpha are involved in acantholysis

Keratinocyte-derived cytokines have been implicated in the pathogenesis of a number of skin diseases. In this study we examined the possible role of keratinocyte-derived cytokines in the development of acantholysis in pemphigus vulgaris. Nineteen patients with pemphigus vulgaris, demonstrating the characteristic clinical, pathologic, and immunopathologic findings were studied. In situ immunolabeling demonstrated the presence of two cytokines interleukin-1alpha and tumor necrosis factor-alpha, in lesional and perilesional areas. Results were confirmed by reverse transcriptase-polymerase chain reaction, demonstrating overexpression of both cytokines in vivo. To study the role of these cytokines in the pathogenesis of pemphigus vulgaris both in vitro and in vivo studies were performed. The results of the in vitro study demonstrated that pemphigus vulgaris IgG induced interleukin-1alpha and tumor necrosis factor-alpha mRNA in the skin. The potential pathogenic role of these mediators was demonstrated by a blocking study using antibodies against human interleukin-1alpha and tumor necrosis factor-alpha in keratinocytes cultures. A combination of anti-interleukin-1alpha and anti-tumor necrosis factor-alpha antibodies inhibited in vitro pemphigus vulgaris IgG induced acantholysis. To confirm the role of interleukin-1 and tumor necrosis factor-alpha in pemphigus, we utilized passive transfer studies using interleukin-1 deficient mice (ICE-/-, interleukin-1beta-/-) and tumor necrosis factor-alpha receptor deficient mice (TNFR1R2-/-). Both groups demonstrated a decreased susceptibility to the passive transfer of pemphigus. Our data support the role of cytokines interleukin-1 and tumor necrosis factor-alpha in the pathogenesis of pemphigus vulgaris.

Defining the role of complement in experimental pemphigus vulgaris in mice

Parenteral passive transfer of human pemphigus vulgaris IgG (PV IgG) into neonatal mice reproduces the cutaneous disease. We used this model to study the role of complement in the development of acantholysis in three steps. Peptic F(ab')2 fragments were prepared from PV IgG and were injected into seven newborn mice, and all animals developed acantholytic skin blisters without local complement activation, as shown by direct immunofluorescence. These fragments were reduced and alkylated to produce Fab' fragments with equivalent in vitro binding activity. The monovalent fragments were given in an identical fashion to five littermates but failed to produce disease even though they were bound in the epidermis in vivo. Intact PV IgG was injected in 20 genetically C5-deficient neonates (B10-D2-OSN strain) and 20 control neonates (B10-D2-NSN, normal complementemic). Extensive blistering, with a positive Nikolsky sign, was produced in all 40 animals. PV IgG was given to 34 BALB/c neonates that were complement depleted by pretreatment with cobra venom factor (CoF) for 24 hr, and to 38 untreated neonates from the same litters. There was no difference in the disease produced after CoF treatment in animals that received high doses of PV IgG (5 to 15 mg/g/day). In animals receiving 2.5 mg PV IgG/g/day, blister formation was delayed and the final extent of the cutaneous lesions was less in CoF-treated mice (n = 12) than in normal complementemic controls (n = 12, p less than 0.02). These results show that complement activation is not an essential mechanism in PV IgG-induced acantholysis in vivo, but it does have an amplifying effect on the development of cutaneous lesions under certain conditions, and lesions can be induced in vivo by bivalent F(ab')2 fragments of PV IgG, but not by the monovalent Fab' fragments, suggesting that cross-linking of the cell surface antigen is an initiating signal in acantholysis.

The vulnerable esophagus: riboflavin deficiency and squamous cell dysplasia of the skin and the esophagus

Eleven male baboons fed a synthetic diet completely lacking in riboflavin developed, after 15-36 weeks, profound macroscopic and microscopic architectural disorganization of the skin, mouth, and esophagus. The cutaneous lesions showed hyperkeratosis, gross derangement of keratinization with acanthosis, and impressive pseudocarcinomatous hyperplasia. In 5 baboons that died or were killed, there were large penetrating lesions having raised epithelial edges at the lower third of the esophagus or at the cardioesophageal junction, with gross epithelial hyperplasia and grossly deranged and thickened keratinization and numerous mitotic figures. None of the 8 control animals given riboflavin showed these abnormalities.

Immuno-electron microscopical features of in vivo antibody binding during pemphigus blister formation. Revelation with a new technique: peroxidase-labeled protein A

Pemphigus autoantibodies, bound in the epidermis during different stages of acantholysis, were demonstrated with a new technique for immuno-electron microscopy. Peroxidase-labeled Protein A was used as a new and specific tracer for tissue-bound antibodies of the IgG-type. Advantages were: (1) A small molecular weight of the tracer, (2) a rapid tissue penetration, and (3) shortened incubation times, thus better preserved tissue fine structures. Unspecific adsorption in tissues and on cells was found to be comparatively low.

Proteinase activation: a mechanism for cellular dyshesion in pemphigus

An in vitro model system using cultured newborn epidermal cells was employed to investigate the binding of pemphigus autoantibody and subsequent loss of adhesion between epidermal cells. Pemphigus antibodies bound to both mouse and human cultured epidermal cells. Incubation of cultured newborn mouse epidermal cells with pemphigus antibody followed by gentle agitation induced loss of adhesion between the epidermal cells and the plastic culture dish. Release of viable epidermal cells from the dish was inhibited by the proteinase inhibitors, soybean trypsin inhibitor and alpha 2-macroglobulin. These observations suggest that pemphigus antibody induces viable epidermal cells to activate cellular proteinases which then degrade the glycocalyx and cause cellular dyshesion and acantholysis.

[Early detection of pemphigus vulgaris: role of the dentist]

Means to detect pemphigus vulgaris at an early stage are described. Its grave evolution in absence of treatment makes an early diagnosis imperative. The first signs are frequently localized in the oral mucosa and sometimes the disease remains confined to this mucosa only. Efficient and early therapy may favourably influence the course of disease, and the dentist is in a prime position to detect the characteristic lesions.

Oral acantholytic itching disease responding to dapsone. Dermatitis herpetiformis, pemphigus, or a new disease?

A patient had a blistering and severely itching disease confined solely to the oral cavity. The histopathologic findings had the features of both pemphigus and dermatitis herpetiformis. There were no gastrointestinal symptoms, no IgA could be found in uninvolved skin, and no intercellular or basement membrane antibodies were present in the serum or epidermis. The disease responded favorable to dapsone (diaminodiphenylsulfone), which could be discontinued after 2 1/2 years. The literature is briefly reviewed, and there is a discussion of whether the patient was suffering from pemphigus or dermatitis herpetiformis. The conclusion is drawn that the diagnosis cannot be established with certainty and that we are perhaps dealing with a new disease. It is stressed that in such aberrant cases a therapeutic trial with dapsone should be made.

Hailey-Hailey disease in a black family

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