The pathogenesis of bullous skin diseases

Paradoxical and bimodal immune-mediated dermatological side effects of TNF-α inhibitors: A comprehensive review

INTRODUCTION

Due to the increasing prevalence of immune-mediated diseases such as psoriasis, lichen planus, rheumatoid arthritis and inflammatory bowel disease, dermatologists have turned to new biologic drugs known as DMARDs (disease-modifying anti-rheumatic drugs) in recent years.

AREAS COVERED

In this study, we evaluate the immune-mediated dermatological side effects of DMARDS by reviewing and analyzing previous peer-reviewed research on the effects of TNF-α inhibitors in the treatment of skin diseases, as well as adverse effects of these drugs and some of the main causes of these effects.

EXPERT OPINION

DMARDs are very effective in improving control of the above diseases. TNF-α inhibitors are an important group of DMARDs that are widely used. The paradoxical adverse events (PAEs) associated with the use of TNF-α inhibitors are divided into three categories: true paradoxical, borderline paradoxical, and non-paradoxical. True PAEs include conditions for which TNF-α inhibitors are approved for treatment. Borderline PAEs are considered to occur with this class of drugs for which there is no definite approval but for which there is sufficient evidence. Although these events are rare, early recognition of the accused drug and appropriate decision-making may prevent progression of complications and irreversible side effects.

Association of Human Endogenous Retrovirus-W (HERV-W) Copies with Pemphigus Vulgaris

BACKGROUND

Pemphigus is classified as a group of chronic, recurrent, and potentially fatal bullous autoimmune diseases that leads to blisters and skin lesions resulting from IgG antibodies and the loss of cellular connections in the epidermis. Human endogenous retrovirus (HERV) sequences and their products (RNA, cytosolic DNA, and proteins) can modulate the immune system and contribute to autoimmunity. The extent to which, HERV-W env copies may be involved in the pathogenesis of pemphigus remains to be elucidated.

AIM

This study aimed to comparatively evaluate the relative levels of HERV-W env DNA copy numbers in the peripheral blood mononuclear cells (PBMCs) of pemphigus vulgaris patients and healthy controls.

METHODS

Thirty-one pemphigus patients and the corresponding age- and sex-matched healthy controls were included in the study. The relative levels of HERV-W env DNA copy numbers were then evaluated by qPCR using specific primers, in the PBMCs of the patients and controls.

RESULTS

Our results indicated that relative levels of HERV-W env DNA copy numbers in the patients were significantly higher than that in the controls (1.67±0.86 vs. 1.17±0.75; p = 0.02). There was also a significant difference between the HERV-W env copies of male and female patients (p = 0.001). Furthermore, there was no relationship between the HERV-W env copy number and disease onset (p = 0.19) . According to the obtained data, we could not find any relationship between the HERV-W env copy number and serum Dsg1(p=0.86) and Dsg3 (p=0.76) levels.

CONCLUSION

Our results indicated a positive link between the HERV-W env copies and pathogenesis of pemphigus. The association between clinical severity score and HERVW env copies in the PBMCs as a biomarker for pemphigus needs further studies.

From Molecular Insights to Clinical Perspectives in Drug-Associated Bullous Pemphigoid

Bullous pemphigoid (BP), the most common autoimmune blistering disease, is characterized by the presence of autoantibodies targeting BP180 and BP230 in the basement membrane zone. This leads to the activation of complement-dependent and independent pathways, resulting in proteolytic cleavage at the dermoepidermal junction and an eosinophilic inflammatory response. While numerous drugs have been associated with BP in the literature, causality and pathogenic mechanisms remain elusive in most cases. Dipeptidyl peptidase 4 inhibitors (DPP4i), in particular, are the most frequently reported drugs related to BP and, therefore, have been extensively investigated. They can potentially trigger BP through the impaired proteolytic degradation of BP180, combined with immune dysregulation. DPP4i-associated BP can be categorized into true drug-induced BP and drug-triggered BP, with the latter resembling classic BP. Antineoplastic immunotherapy is increasingly associated with BP, with both B and T cells involved. Other drugs, including biologics, diuretics and cardiovascular and neuropsychiatric agents, present weaker evidence and poorly understood pathogenic mechanisms. Further research is needed due to the growing incidence of BP and the increasing identification of new potential triggers.

Research Progress of Dihydroquercetin in the Treatment of Skin Diseases

Skin is a barrier to maintaining the stability of the human environment and preventing the invasion of pathogens. When skin tissue is exposed to the external environment, it will inevitably develop defects due to trauma, injury, burns, ulcers, surgery, and chronic diseases. Rapid skin repair is the key to reducing infection, relieving pain, and improving quality of life. Dihydroquercetin is a kind of flavonoid that has a wide range of pharmacological activities and can improve skin repair, skin inflammation, skin cancer, and so on. In this paper, the application of dihydroquercetin in medical dressings and the research progress in the treatment of skin-related diseases are reviewed, so as to provide reference for further developing dihydroquercetin as a drug for the treatment of skin diseases.

Necrotizing Fasciitis-Severe Complication of Bullous Pemphigoid: A Systematic Review, Risk Factors, and Treatment Challenges

Background and objectives: Bullous pemphigoid (BP), the most common subepidermal autoimmune skin blistering disease (AIBD) has an estimated annual incidence of 2.4 to 42.8 new cases per million in different populations, designating it an orphan disease. Characterized by disruption of the skin barrier combined with therapy-induced immunosuppression, BP could pose a risk for skin and soft tissue infections (SSTI). Necrotizing fasciitis (NF) is a rare necrotizing skin and soft tissue infection, with a prevalence of 0.40 cases per 100,000 to 15.5 cases per 100,000 population, often associated with immunosuppression. Low incidences of NF and BP classify them both as rare diseases, possibly contributing to the false inability of making a significant correlation between the two. Here, we present a systematic review of the existing literature related to the ways these two diseases correlate. Materials and methods: This systematic review was conducted according to the PRISMA guidelines. The literature review was conducted using PubMed (MEDLINE), Google Scholar, and SCOPUS databases. The primary outcome was prevalence of NF in BP patients, while the secondary outcome was prevalence and mortality of SSTI in BP patients. Due to the scarcity of data, case reports were also included. Results: A total of 13 studies were included, six case reports of BP complicated by NF with six retrospective studies and one randomized multicenter trial of SSTIs in BP patients. Conclusions: Loss of skin integrity, immunosuppressive therapy, and comorbidities commonly related to BP patients are risk factors for necrotizing fasciitis. Evidence of their significant correlation is emerging, and further studies are deemed necessary for the development of BP-specific diagnostic and treatment protocols.

Autoimmune bullous diseases in pregnancy: an overview of pathogenesis, clinical presentations, diagnostics and available therapies

Autoimmune bullous diseases (AIBDs) are rare organ-specific diseases characterized by the appearance of blisters and erosions on the skin and mucous membranes. These dermatoses are marked by the development of autoantibodies targeting the autoantigens located in intercellular junctions, i.e., between keratinocytes or in the basement membrane area. Therefore, the fundamental division of AIBDs into the pemphigus and pemphigoid groups exists. Although AIBDs are uncommon in the general population, their overall incidence is somewhat higher in women of all ages, for which a pregnant women can be likely affected too. While the pemphigoid gestationis is exclusive bullous dermatosis of pregnancy, the other AIBDs can also start or worsen during this period. The appearance of AIBDs in childbearing women is a particularly sensitive situation requiring exceptional clinicians' caution due to the possibility of pregnancy complications with adverse effects and risks to the mother and the child. Also, there are numerous management difficulties in the period of pregnancy and lactation related to the drugs' choice and safety. This paper aimed to outline the pathophysiologic mechanisms, clinical manifestations, diagnostic approach and therapy of the most commonly recognized AIBDs in pregnancy.

Occurrence of autoantibodies against skin proteins in patients with hereditary epidermolysis bullosa predisposes to development of autoimmune blistering disease

Skin blistering disorders are associated with inherited defects in proteins involved in the dermal-epidermal adhesion or autoantibodies targeting those proteins. Although blistering in hereditary epidermolysis bullosa (EB) is pathogenetically linked to genetic deficiency of distinct proteins of the epidermis or the dermal-epidermal junction, circulating autoantibodies against these proteins have also been identified in EB patients. So far, autoantibodies have been considered bystanders in EB and active pathogenicity of them in EB has not been disclosed. In sera of a cohort of 258 EB patients, we found by ELISA in 22% of the patients autoantibodies against the bullous pemphigoid antigen BP180. The titers correlated negatively with collagen VII skin expression and positively with disease severity. Among those patients, we identified six (2.33%) with clinical features of an autoimmune bullous disorder (AIBD) and positive indirect immunofluorescence (IIF) staining. In literature, we found four more cases of EB patients developing disease-aggravating AIBD. Co-existence of these two rare skin disorders suggests that EB patients have a predisposition for the development of AIBD. Our work highlights that EB patients with increased itch or blister formation should be evaluated for additional AIBD and repeated screening for changes in autoantibody titers and skin-binding specificities is advised.

Immunotherapy for Pemphigus: Present and Future

Pemphigus is a chronic and severe autoimmune bullous disease caused by autoantibodies targeting adhesion molecules between keratinocytes. It requires 2–3 years on average to manage the disease. To date, although Rituximab combined with short-term systemic glucocorticoids was accepted as first-line therapy, systemic glucocorticoids remain the primary therapeutic option for pemphigus patients, successfully decreasing morbidity and mortality from pemphigus. However, novel therapeutic strategies are desirable due to the low efficacy in some subset of patients and the long-term severe adverse effects of traditional therapies. Recently, immunotherapy has proved to be encouraging for disease control or cure. Based on the current understanding of the immune mechanisms of pemphigus, we review the immune targets and corresponding agents applied in practice or under clinical trials. The goals of the novel treatments are to improve the quality of life of pemphigus patients by improving efficacy and safety, minimizing side effects, achieving fast disease control, or curing the disease.

Oral Health, Antimicrobials and Care for Patients With Chronic Oral Diseases – A Review of Knowledge and Treatment Strategies

Periodontal and chronic oral mucosal diseases are significant life impacting conditions which may co-exist and synergistically act to cause more severe and widespread oral pathology with enhanced challenges in effective management. Clinicians regularly observe these effects and struggle to effectively manage both problems in many patients. There is limited understanding of many basic and applied scientific elements underpinning potentially shared aetiopathological features and management. Recent developments in translational science provide an opportunity to greater improve knowledge and subsequently care for patients with these problems.

Bullous pemphigoid: An immune disorder related to aging (Review)

Bullous pemphigoid (BP) is the most frequent subepidermal autoimmune blistering disease and is caused by autoantibodies directed against two principal antigens of the hemidesmosome, BP antigen 180 and BP antigen 230. The pathogenesis of BP is dependent upon the interaction between genetic predisposition, physiological skin alterations due to aging and specific triggers. Several triggers have already been reported to induce this disease and include drugs, thermal or electrical burns, surgical procedures, trauma, UV radiation, radiotherapy, chemicals and infections. Data from the current literature support the hypothesis that alterations of the skin barrier associated with aging increase individual susceptibility to these aforementioned triggers. Consequently, this has been reported to lead to the attack of autoantibodies, demonstrating the predilection of BP for the elderly population. The identification of triggering factors and comorbidities may aid in understanding the pathogenesis of BP and improve clinical management by encouraging their prompt recognition and removal. Moreover, the present review has indicated that current management of BP should be aimed at counteracting the detrimental effects of aging on the skin by restoring skin barrier integrity and maintaining cutaneous homeostasis, for example with systematic applications of topical emollients and photoprotection. This strategy could prove even more beneficial in the elderly, in which frequent comorbidities associated with age often narrow available immunosuppressive treatment options. Furthermore, the safety of treatment regimens may significantly affect outcome and prognosis.

Bipolar Patients and Bullous Pemphigoid after Risperidone Long-Acting Injectable: A Case Report and a Review of the Literature

Neuropsychiatric disorders are found to be associated with bullous pemphigoid (BP), an autoimmune subepidermal blistering disease. Antipsychotics have emerged as possible inducing factors of BP. However, large sample studies concerning BP associated with antipsychotics, as well as with specific mental disorders, are still lacking. Our review retrieved a few clinical studies and case reports on the topic, producing controversial results. We report for the first time a bipolar patient case presenting BP following five-month therapy with risperidone long-acting injectable (LAI). We hypothesize that the dermatological event is associated with the medication administered. The issue emerged during psychiatric consultation and was confirmed by histological examination, direct and indirect immunofluorescence studies, plus positive plasma and cutaneous BP180 and BP230 IgG. Neurodegeneration or neuroinflammation might represent a primary process leading to a cross-reactive immune response between neural and cutaneous antigens and contributing to self-tolerance failure. Furthermore, the time sequence of the shared biological mechanisms leading to clinical manifestations of the neuropsychiatric disorder and BP remains undefined. BP comorbid with bipolar disorder might occasionally represent a serious health risk and affect patients' physical and psychosocial quality of life. Thus, clinicians treating psychiatric patients should consider BP as a possible adverse effect of psychotropic medications.

Application of photodynamic therapy in immune-related diseases

Photodynamic therapy (PDT) is a therapeutic modality that utilizes photodamage caused by photosensitizers and oxygen after exposure to a specific wavelength of light. Owing to its low toxicity, high selectivity, and minimally invasive properties, PDT has been widely applied to treat various malignant tumors, premalignant lesions, and infectious diseases. Moreover, there is growing evidence of its immunomodulatory effects and potential for the treatment of immune-related diseases. This review mainly focuses on the effect of PDT on immunity and its application in immune-related diseases.

Utility of Direct Immunofluorescence in Cutaneous Autoimmune Bullous Disorders

Background Autoimmune bullous disorders (AIBD) are a heterogeneous group of disorders with substantial clinical overlap associated with blistering of skin or mucosa. Aims The present study aimed to study the histopathological spectrum and evaluate the utility of direct immunofluorescence (DIF) on snap-frozen and paraffin-embedded sections in resolving the differential diagnosis of AIBD and connective tissue disorders of the skin. We also compared the efficacy of DIF on paraffin versus the snap-frozen sections in diagnosing AIBD. Methods The present study was conducted for three years (2017-2019) and included 27 biopsies. We also included a retrospective analysis that included 25 biopsies collected over three years (2014-2017). Histopathological examination and DIF were conducted on all samples. Results Pemphigus vulgaris was the most common autoimmune cutaneous disorder constituting 37% (n = 10) in prospective and 36% (n = 9) in the retrospective study. DIF showed a specificity of 81.25% in our prospective study. While on the paraffin-embedded sections, it showed a specificity of 66.6% in our retrospective study. In the prospective study, DIF on paraffin-embedded sections had a positivity rate of 43.75% as compared to 81.25% in DIF done on snap-frozen sections. Conclusion DIF is a sensitive tool for the diagnosis as well as distinguishing immune-mediated bullous disorders from other lesions primarily when performed on snap-frozen sections. The diagnostic yield is enhanced by DIF in cases that pose a diagnostic dilemma both clinically and histologically. The final diagnosis depends on all clinical, histopathological and immunofluorescence findings.

[Skin aging: Pathophysiology and innovative therapies]

One of the major challenges of the 21^st century is the fight against aging, defined as a set of physiological mechanisms altering the physical and intellectual capacities of human beings. Aging of the skin is only one visible part of this process. It is associated with major healing defects linked in part to the alteration of the biomechanical properties of skin cells, mainly dermal fibroblasts. The immune system, another key component in maintaining skin homeostasis and the efficient healing of wounds, also suffers the effects of time: the consequent skin immunosenescence would limit the anti-infectious and vaccine response, while promoting a pro-tumor environment. The main skin damages due to aging, whether intrinsic or extrinsic, will be detailed before listing the effective anti-aging strategies to combat age-related dermal and epidermal stigmas.

Bullous pemphigoid-like skin rash associated with Rivaroxaban use in a very elderly patient with multimorbidity and chronic kidney disease: A case report

Direct oral anticoagulants (DOACs) are increasingly being used in the elderly population in view of its ease of use, efficacy, and favorable side-effect profile compared with the vitamin K antagonists. However, there is a need for increase awareness of well-characterized cases, albeit a small number, of bullous pemphigoid-like skin reactions associated with rivaroxaban.