Paraneoplastic Pemphigus Autoantibodies Against C-terminus of Desmoplakin Induced Acantholysis In Vitro and In Vivo.

Paraneoplastic pemphigus (PNP) is an autoimmune bullous disease associated with underlying neoplasms and characterized by antibodies against desmoglein 3 (Dsg 3) and plakins. Autoantibodies against desmoglein 3 in sera of patients with PNP have been proven to cause acantholysis in vivo in neonatal mice. As a member of the plakin family, autoantibodies against desmoplakin were detected frequently by immunoprecipitation in the sera of PNP. The recombinant C-terminus of desmoplakin was expressed and purified to adsorb the specific autoantibodies against the C-terminus of desmoplakin. In vitro dispase-dependent keratinocyte dissociation assay and in vivo IgG passive transfer into neonatal mice assay were performed, followed by the electronic microscopy examination and TUNEL assay. We found that anti-C terminus of desmoplakin autoantibodies caused blisters and acantholysis in mice skin at a dose-dependent manner. Moreover, dissociated fragments were observed after incubation with the purified IgG against desmoplakin, compared with normal human IgG (P-value =0.0207). The electronic microscopy examination showed the disconnection of keratin intermediate filaments from desmosomes. Lastly, apoptosis of keratinocytes in the TUNEL assay was all detected in the skins of neonatal mice after injection of the anti-C terminus of desmoplakin autoantibodies. Taken together, the study suggests that autoantibodies against the C-terminus of desmoplakin might be pathogenic in PNP.

Chronic exposure to the anti-M3 muscarinic acetylcholine receptor autoantibody in pemphigus vulgaris contributes to disease pathophysiology.

Pemphigus vulgaris (PV) is a potentially lethal autoimmune mucocutaneous blistering disease characterized by binding of IgG autoantibodies (AuAbs) to keratinocytes (KCs). In addition to AuAbs against adhesion molecules desmogleins 1 and 3, PV patients also produce an AuAb against the M3 muscarinic acetylcholine (ACh) receptor (M3AR) that plays an important role in regulation of vital functions of KCs upon binding endogenous ACh. This anti-M3AR AuAb is pathogenic because its adsorption eliminates the acantholytic activity of PV IgG; however, the molecular mechanism of its action is unclear. In the present study, we sought to elucidate the mode of immunopharmacologic action of the anti-M3AR AuAb in PV. Short-term exposures of cultured KCs to PV IgG or the muscarinic agonist muscarine both induced changes in the expression of keratins 5 and 10, consistent with the inhibition of proliferation and upregulated differentiation and in keeping with the biological function of M3AR. In contrast, long-term incubations induced a keratin expression pattern consistent with upregulated proliferation and decreased differentiation, in keeping with the hyperproliferative state of KCs in PV. This change could result from desensitization of the M3AR, representing the net antagonist-like effect of the AuAb. Therefore, chronic exposure of KCs to the anti-M3AR AuAb interrupts the physiological regulation of KCs by endogenous ACh, contributing to the onset of acantholysis. Since cholinergic agents have already demonstrated antiacantholytic activity in a mouse model of PV and in PV patients, our results have translational significance and can guide future development of therapies for PV patients employing cholinergic drugs.

Case of Bullous Grover Disease.

ABSTRACT: Grover disease is an acquired acantholytic dermatosis affecting middle-aged men, with pruritus being the most commonly associated symptom. Grover disease tends to wax and wane and can last between several months to several years. Although Grover disease is usually papular, we report here a patient who presented with mainly vesicular and bullous lesions on his back originally concerning for folliculitis, contact dermatitis, or disseminated herpes simplex viral infection. Skin biopsy demonstrated acantholysis, suprabasal blisters, and a predominantly lymphocytic dermal infiltrate. Tzanck preparation for giant cells, immunohistochemistry for viral markers, and direct immunofluorescence staining were all negative. A diagnosis of bullous Grover disease was made based on clinicopathological correlation. Minocycline was recommended based on report of its efficacy. However, patient declined treatment and his rash self-resolved within a couple of months. This case brings awareness to this atypical variant of Grover disease and encourages physician to include Grover disease in their differential of vesiculobullous disorders.

Peristomal Punctate Pemphigus.

ABSTRACT: Cutaneous reactions surrounding abdominal stoma sites are typically irritant, allergic, infectious, traumatic or pathergic in etiology. Pemphigus, which encompasses a group of vesiculobullous autoimmune skin disorders, is seldom encountered as a peristomal dermatosis. Direct immunofluorescence (DIF) studies of pemphigus generally show continuous intercellular net-like depositions of IgG. However, punctate or dot-like intercellular deposition of IgG can also be seen in cases of pemphigus. The punctuate pattern is underreported in the literature and little is known about its implication. We describe a case of a 58-year-old Caucasian man with a history of bowel obstruction, status postcolostomy, who presented with a sharply demarcated, erythematous, crusted plaque surrounding his abdominal stoma. The patient endorsed persistent pruritus. A punch biopsy of the lesion was performed for clinical suspicion of fungal infection versus irritant dermatitis. Histopathology revealed a predominantly subcorneal acantholytic dermatitis. Periodic acid-Schiff with diastase and Grocott methenamine silver histochemical stains were negative for fungi. DIF was positive for IgG and C3 detected in a punctate intercellular pattern. In conjunction with the patient's clinical presentation and DIF, a diagnosis of peristomal pemphigus foliaceous was rendered. Herein, we describe a case of punctate pemphigus presenting as a peristomal dermatosis and include a review of the literature to raise awareness of this phenomenon.

Grover Disease Associated With Chemotherapy: Review of Potential Pathophysiology, Current Treatments, and Future Directions.

INTRODUCTION: Transient acantholytic dermatosis has been frequently reported in patients with malignancies. While paraneoplastic cases have rarely been reported, most eruptions occur in the setting of chemotherapeutic agents. Management is based on limited data and primarily with topical steroids and topical emollients. A subset of patients exhibits recalcitrant disease and require alternate therapeutic approachesMethods: This systematic review consisted of identifying records in PubMed using the medical subject headings (MeSH) terms “chemotherapy” AND “Grover”, “chemotherapy” AND “Grover’s”, “cancer” AND “Grover”, “cancer” AND “Grover’s”, “malignancy” AND “Grover”, “malignancy” AND “Grover’s”, as well as a free text search for “Grover” OR “Grover’s” OR “Grover disease” OR “Grovers disease” OR “Grover’s disease” OR “transient acantholytic dermatosis” OR “transient acantholytic” to identify case reports, case series, systematic reviews, review articles, meta-analyses, clinical trials, brief commentaries, and original articles. The titles and abstracts of all results were reviewed. Full texts of relevant results were then read in their entirety and applicability was determined. RESULTS: Overall, Grover disease has rarely been reported in the setting of malignancy. When it occurs, it is generally in the setting of chemotherapy use. Chemotherapy-associated Grover disease is reported most frequently in association with cytotoxic chemotherapies, followed by small molecule inhibitors. The first line treatment for this complication is the use of topical agents. When these provide inadequate relief, alternate therapies have been rarely reported, with novel treatments proposed based on the type of chemotherapy agent and its mechanism of action. CONCLUSIONS: Chemotherapy-associated Grover disease is an uncommon complication of cancer treatment. While most cases of chemotherapy-associated Grover disease can be treated with topical steroids and topical emollients, certain cases require a more specialized approach. This could include adjuvant adjuvant therapies, or novel treatments that are directly related to the mechanism of action of the chemotherapy involved. J Drugs Dermatol. 2020;19(11):1056-1064. doi:10.36849/JDD.2020.5648.

Evaluation of the pathogenicity of anti-desmoglein antibodies of pemphigus vulgaris patients using human organ culture assay.

Anti-desmoglein (anti-Dsg) antibodies are key players in the pathogenesis of pemphigus vulgaris (PV) disease. We aimed to evaluate the pathogenicity of anti-Dsg antibodies of PV patients using human organ culture assay and to assess the correlation between the pathogenicity and the disease score. In this cross-sectional study, sera from 37 PV patients were included. The organ culture acantholysis index (OCAI) was calculated as (width of blister/total width of the specimen) × 100. The sera were analyzed using Dsg ELISAs and ethylenediaminetetraacetic acid (EDTA) treated ELISAs. OCAI ranged from 0 to 100%, median = 50%. There was a moderate significant correlation between OCAI and the disease severity, r = 0.503, p = 0.002. There was a moderate significant correlation between OCAI and non-Ca2+-dependent anti-Dsg3 and anti-Dsg1 antibodies, p values were 0.01 and 0.021, respectively. The OCAI was assessed along the disease time course of four patients. The OCAI fluctuated parallel to the disease severity along the time course of the four patients. Human organ culture assay is an objective tool that detects the pathogenicity of anti-desmoglein antibodies. It can be used before stopping systemic steroids especially in patients in remission with high titer or if the Dsg ELISA is not available.

Gluteal hidradenitis suppurativa presenting pemphigus-like findings: case report.

BACKGROUND: Hidradenitis suppurativa is one member of the follicular occlusion triad: acne conglobata, hidradenitis suppurativa, and dissecting cellulitis of the scalp. The presence of acantholysis and desmoglein autoantibodies in hidradenitis suppurativa is rare. CASE PRESENTATION: We report a case of 68-year-old male with a diagnosis of gluteal hidradenitis suppurativa co-presenting pemphigus-like findings including acantholysis and positive desmoglein autoantibodies. CONCLUSION: To our knowledge, comorbidity of gluteal hidradenitis suppurativa and pemphigus-like findings has not been reported before. This case implies a relationship between two different conditions; the follicular occlusion triad and pemphigus, highlighting a potential induction of pemphigus-like lesion by chronic inflammatory process.

Acantholysis may precede elevation of circulating anti-desmoglein 3 antibody levels in pemphigus vulgaris presenting with desquamative gingivitis.

Pemphigus vulgaris (PV) is an autoimmune, blistering disease that affects the mucosa and skin. The current theory favors the concept that anti-desmoglein (Dsg) 3 autoimmunity is the only pathogenic event needed to induce acantholysis. However, a few cases of active PV in the oral cavity had no detectable anti-Dsg 3 antibody. The aim of this study was to evaluate the differences in clinical and laboratory findings, whether or not the anti-Dsg 3 antibodies were present. This study was based on a retrospective review of 10 PV cases. The evaluation of the circulating autoantibody titers to Dsg 3 was conducted by using enzyme-linked immunosorbent assay (ELISA). An index value of 20 or more was used as the cutoff for a positive reaction. Only five of the 10 PV cases had a positive Dsg 3 ELISA. There were no differences in clinical, cytological, histopathological, and direct immunofluorescence findings, whether or not the anti-Dsg 3 antibodies were present. Of the five patients with a negative reaction at the time of diagnosis, the Dsg 3 ELISA became positive in the follow-up period in three cases. In the remaining two cases, the Dsg 3 ELISA was consistently negative for 18 months. Dsg 3 ELISA was negative early in some PV cases. Therefore, PV acantholysis may precede the elevation of circulating anti-Dsg 3 antibody levels. The diagnosis of PV should be considered based on comprehensive clinical, histopathological, and immunofluorescent criteria.

Grover disease and bullous pemphigoid: a clinicopathological study of six cases.

Grover disease (GD) is an idiopathic dermatosis that typically manifests as itchy papules over the trunk in middle-aged men. Bullous pemphigoid (BP) is an autoimmune bullous disease that affects older people. Not only are the two diseases easily distinguishable on clinical grounds, they are also characterized by differences in histopathology, pathogenesis and response to treatment Thus, the co-occurrence of these two conditions in the same patient is usually considered coincidental. In this report, we present a multicentre retrospective analysis of six patients who developed both GD and BP over a short period of time, and in all cases but one, GD preceded BP. We discuss the clinical and histopathological features of these patients, and the suggested mechanisms of the diseases. We conclude that GD might predispose to the development of BP.

Acute Infection and Subsequent Subclinical Reactivation of Herpes Simplex Virus 2 after Vaginal Inoculation of Rhesus Macaques.

Herpes simplex virus 2 (HSV-2) is a common sexually transmitted infection with a highly variable clinical course. Many infections quickly become subclinical, with episodes of spontaneous virus reactivation. To study host-HSV-2 interactions, an animal model of subclinical HSV-2 infection is needed. In an effort to develop a relevant model, rhesus macaques (RM) were inoculated intravaginally with two or three HSV-2 strains (186, 333, and/or G) at a total dose of 1 × 107 PFU of HSV-2 per animal. Infectious HSV-2 and HSV-2 DNA were consistently shed in vaginal swabs for the first 7 to 14 days after each inoculation. Proteins associated with wound healing, innate immunity, and inflammation were significantly increased in cervical secretions immediately after HSV-2 inoculation. There was histologic evidence of acute herpesvirus pathology, including acantholysis in the squamous epithelium and ballooning degeneration of and intranuclear inclusion bodies in epithelial cells, with HSV antigen in mucosal epithelial cells and keratinocytes. Further, an intense inflammatory infiltrate was found in the cervix and vulva. Evidence of latent infection and reactivation was demonstrated by the detection of spontaneous HSV-2 shedding post-acute inoculation (102 to 103 DNA copies/swab) in 80% of RM. Further, HSV-2 DNA was detected in ganglia in most necropsied animals. HSV-2-specifc T-cell responses were detected in all animals, although antibodies to HSV-2 were detected in only 30% of the animals. Thus, HSV-2 infection of RM recapitulates many of the key features of subclinical HSV-2 infection in women but seems to be more limited, as virus shedding was undetectable more than 40 days after the last virus inoculation.IMPORTANCE Herpes simplex virus 2 (HSV-2) infects nearly 500 million persons globally, with an estimated 21 million incident cases each year, making it one of the most common sexually transmitted infections (STIs). HSV-2 is associated with increased human immunodeficiency virus type 1 (HIV-1) acquisition, and this risk does not decline with the use of antiherpes drugs. As initial acquisition of both HIV and HSV-2 infections is subclinical, study of the initial molecular interactions of the two agents requires an animal model. We found that HSV-2 can infect RM after vaginal inoculation, establish latency in the nervous system, and spontaneously reactivate; these features mimic some of the key features of HSV-2 infection in women. RM may provide an animal model to develop strategies to prevent HSV-2 acquisition and reactivation.

Oral pemphigus.

The involvement of the oral mucosa in patients affected by pemphigus vulgaris (PV), paraneoplastic, IgA pemphigus, and in some cases iatrogenic pemphigus is common and often a prelude to skin lesions. Intraepidermal bullae are caused by acantholysis, induced by IgG autoantibodies directed against the desmosomes and the domain of numerous keratinocytes self-antigens desmogleins (namely cadherins), thus supporting the autoimmune nature of the disease. Apoptosis may contribute to the acantholysis. Oral mucosal lesions are more commonly refractory to treatment compared to skin lesions and have been associated with disease duration, disease location and possibly the presence of HSV DNA in the oral cavity. Recent publications have stressed the positive role of Rituximab in early disease treatment.

Pemphigus, a pathomechanism of acantholysis.

Autoantibodies to the desmosomal proteins desmoglein 1 and 3 cause pemphigus foliaceus and pemphigus vulgaris, which are characterised by keratinocyte dissociation (acantholysis) and intraepidermal blister formation. The passive transfer of pathogenic anti-desmoglein antibodies induces blisters in mice in vivo and the loss of keratinocyte adhesion in vitro. The pathogenetic mechanisms of acantholysis due to anti-desmoglein autoantibodies are not fully understood. However, recent studies have revealed that signalling-dependent and signalling-independent pathways are operative in the loss of cell adhesion. In this review, we focus on the pathomechanism of acantholysis due to autoantibodies to desmogleins and recent therapeutic approaches.

Pseudoherpetic transient acantholytic dermatosis (Grover disease): case series and review of the literature.

A total of 3 cases of pseudoherpetic transient acantholytic dermatosis (Grover disease) are presented, followed by a brief review of prior reports. All 3 patients were above the age of 60 and presented with a pruritic eruption composed of papules with or without vesicles distributed on the trunk. For all 3 patients, the clinical differential diagnosis included drug eruption but did not include Grover disease; in 1 patient, the clinical impression included herpesvirus infection. Similar histologic and immunohistochemical findings were demonstrated in all 3 cases. Intraepidermal vesicles with acantholysis, multinucleation and hypereosinophilic keratinocytes mimicking necrosis raised the possibility of herpesvirus infection. However, the focality of the process at scanning magnification, absence of true cytopathic effect despite multinucleation, and identification of dyskeratosis rather than true necrosis all permitted for morphologic distinction as pseudoherpetic change. Immunohistochemistry, negative for herpes simplex virus and varicella zoster virus antigens, also distinguished pseudoherpetic change in these patients from a true herpesvirus infection. This series highlights an uncommon histologic variant of a common disorder and describes morphologic and immunohistochemical findings to facilitate its distinction from true herpesvirus infection.

Locations of acantholysis in pemphigus vulgaris and pemphigus foliaceus.

BACKGROUND: Acantholysis in pemphigus vulgaris (PV) and pemphigus foliaceus (PF) occurs predominantly in the suprabasal area and the granular layer, respectively. However, acantholysis can occasionally be observed in unusual locations. METHODS: We retrospectively studied the acantholysis locations in 35 PV and 27 PF cases, and analyzed them using the index value of Desmoglein (Dsg) 1 and Dsg3 by enzyme-linked immunosorbent assay, clinical data, and inflammatory cells. We also analyzed the relationship between clinical subtype and various parameters. RESULTS: In PV, acantholysis was noted in the suprabasal area in 3 cases, in the lower half of the epidermis in 19 cases, and throughout the epidermis in 13 cases. In PF, acantholysis was observed in the granular layer in 6 cases, in the upper half of the epidermis in 14 cases, and throughout the epidermis in 7 cases. Mean index value of Dsg1 in PV patients with acantholysis throughout the epidermis was 2-fold higher than other PV patients. Neutrophils tended to infiltrate the dermis and epidermis more in PF than in PV. CONCLUSIONS: Higher Dsg1 index values seem to correlate with acantholysis in the upper part of the epidermis in PV. Neutrophils may play some role in unusual acantholysis locations in PF.

Pemphigus vulgaris: a multidisciplinary approach to management.

Pemphigus vulgaris (PV) is a rare but potentially life-threatening autoimmune disease affecting the mucosa and the skin. The disease is caused by circulating antibodies to desmosomes (important adhesion proteins linking cells together). Disruption of these intercellular connections results in a loss of cohesion between cells (acantholysis). The clinical result of this process is the development of multiple blisters that easily rupture, leaving behind painful sloughing eroded areas of mucosa and/or skin. We report a case of severe PV in a 56-year-old man presenting with widespread, painful, eroded mucocutaneous lesions. The severity of the disease demanded a range of medical and surgical specialties to successfully manage the problem. This paper highlights the importance of an early multidisciplinary team approach to improve the outcome of patients suffering with this disease.

Is Grover's disease an autoimmune dermatosis?

Grover's disease (GD) is a transient or persistent, monomorphous, papulovesicular, asymptomatic or pruritic eruption classified as non-familial acantholytic disorder. Contribution of autoimmune mechanisms to GD pathogenesis remains controversial. The purpose of this study was to investigate antibody-mediated autoimmunity in 11 patients with GD, 4 of which were positive for IgA and/or IgG antikeratinocyte antibodies by indirect immunofluorescence. We used the most sensitive proteomic technique for an unbiased analysis of IgA- and IgG-autoantibody reactivities. Multiplex analysis of autoantibody responses revealed autoreactivity of all 11 GD patients with cellular proteins involved in the signal transduction events regulating cell development, activation, growth, death, adhesion and motility. Semiquantitative fluorescence analysis of cultured keratinocytes pretreated with sera from each patient demonstrated decreased intensity of staining for desmoglein 1 and/or 3 and PCNA, whereas 4 of 10 GD sera induced BAD expression, indicating that binding of autoantibodies to keratinocytes alters expression/function of their adhesion molecules and activates apoptosis. We also tested the ability of GD sera to induce visible alterations of keratinocyte shape and motility in vitro but found no specific changes. Thus, our results demonstrated that humoral autoimmunity in GD can be mediated by both IgA and IgG autoantibodies. At this point, however, it is impossible to conclude whether these autoantibodies cause or are caused by the disease. Antidesmoglein antibodies may be triggered by exposure to immune system of sequestered antigens due to disintegration of desmosomes during primary acantholysis. Clarifying aetiology of GD will help improve treatment, which currently is symptomatic and of marginal effectiveness.

Desmosomal adhesion and pemphigus vulgaris: the first half of the story.

Pemphigus vulgaris (PV) is a paradigm of autoimmune disease affecting intercellular adhesion. The mechanisms that lead to cell-cell detachment (acantholysis) have crucial therapeutic implications and are currently undergoing major scrutiny. The first part of this review focuses on the classical view of the pathogenesis of PV, which is dominated by the cell adhesion molecules of the desmosome, namely desmogleins (Dsgs). Cloning of the DSG3 gene, generation DSG3 knock-out mice and isolation of monoclonal anti-Dsg3 IgG have aided to clarify the pathogenic mechanisms of PV, which are in part dependent on the fate of desmosomal molecules. These include perturbation of the desmosomal network at the transcriptional, translational, and interaction level, kinase activation, proteinase-mediated degradation, and hyper-adhesion. By the use of PV models, translational research has in turn helped shed light into the basic structure, function, and dynamics of assembly of desmosomal cadherins. The combined efforts of basic and applied research has resulted in tremendous advance into the understanding of epidermal adhesion and helped debunk old myths on the supposedly unique role of desmogleins in the mechanisms of cell-cell detachment in PV.

Peptide-mediated desmoglein 3 crosslinking prevents pemphigus vulgaris autoantibody-induced skin blistering.

In pemphigus vulgaris, a life-threatening autoimmune skin disease, epidermal blisters are caused by autoantibodies primarily targeting desmosomal cadherins desmoglein 3 (DSG3) and DSG1, leading to loss of keratinocyte cohesion. Due to limited insights into disease pathogenesis, current therapy relies primarily on nonspecific long-term immunosuppression. Both direct inhibition of DSG transinteraction and altered intracellular signaling by p38 MAPK likely contribute to the loss of cell adhesion. Here, we applied a tandem peptide (TP) consisting of 2 connected peptide sequences targeting the DSG adhesive interface that was capable of blocking autoantibody-mediated direct interference of DSG3 transinteraction, as revealed by atomic force microscopy and optical trapping. Importantly, TP abrogated autoantibody-mediated skin blistering in mice and was effective when applied topically. Mechanistically, TP inhibited both autoantibody-induced p38 MAPK activation and its association with DSG3, abrogated p38 MAPK-induced keratin filament retraction, and promoted desmosomal DSG3 oligomerization. These data indicate that p38 MAPK links autoantibody-mediated inhibition of DSG3 binding to skin blistering. By limiting loss of DSG3 transinteraction, p38 MAPK activation, and keratin filament retraction, which are hallmarks of pemphigus pathogenesis, TP may serve as a promising treatment option.

Autoreactive T cells in the immune pathogenesis of pemphigus vulgaris.

Pemphigus vulgaris is a life-threatening autoimmune blistering disease caused by anti-desmoglein IgG autoantibodies that finally lead to acantholysis presenting clinically as progressive blistering. Whilst the production of pathogenic antibodies is key to the development of pemphigus vulgaris, many immunological steps are required prior to autoantibody induction. We review advances in the understanding of these immunologic processes with a focus on human leucocyte antigen polymorphisms and antigen recognition, epitope spreading, central and peripheral tolerance, T helper differentiation, induction of pro- and anti-inflammatory cytokines and T-cell regulation of B cells. Targeting autoaggressive T cells as regulators and stimulators of B-cell antibody production should allow for more specific therapeutic immune interventions, avoiding the global immunosuppression seen with many commonly used immunosuppressants in pemphigus vulgaris.