Basement membrane zone IgE deposition is associated with bullous pemphigoid disease severity and treatment results

Advancements in Bullous Pemphigoid Treatment: A Comprehensive Pipeline Update

ABASTRACT

Bullous pemphigoid (BP) is a common autoimmune bullous disease affecting mainly the elderly, with rising incidence due to increased life expectancy. This disease is characterized by tense bullous lesions on normal or erythematous skin, accompanied by pruritus. BP pathogenesis involves autoantibodies against hemidesmosomal proteins BP180 and BP230, leading to detachment at the dermo-epidermal junction as well as blister formation. BP is associated with coexisting comorbidities and drug exposure, and its management often requires high doses or chronic use of systemic glucocorticoids, posing risks of adverse effects. This review focuses on novel treatment options for BP, exploring therapies targeting different immune pathways. Rituximab, a CD20 monoclonal antibody, depletes B-lymphocytes and has shown efficacy in severe cases. Dupilumab, targeting interleukin (IL)-4 receptor α and thus blocking IL-4 and IL-13, downregulates type 2 helper (Th2) responses and has demonstrated promising results. Targeting eosinophil-related molecules using bertilimumab and AKST4290 has yielded positive results in clinical trials. Omalizumab, an immunoglobulin (Ig) E antibody, can reduce disease severity and allows corticosteroid tapering in a number of cases. Complement inhibitors such as nomacopan and avdoralimab are being investigated. IL-17 and IL-23 inhibitors such as secukinumab and tildrakizumab have shown potential in a limited number of case reports. Neonatal Fc receptor antagonists such as efgartigimod are under investigation. Additionally, topical therapies and Janus kinase inhibitors are being explored as potential treatments for BP. These novel therapies offer promising alternatives for managing BP, with potential to improve outcomes and reduce high cumulative doses of systemic corticosteroids and related toxicities. Further research, including controlled clinical trials, is needed to establish their efficacy, safety, and optimal dosing regimens for BP management.

Autoreactive IgE: Pathogenic role and therapeutic target in autoimmune diseases

Autoimmunity is the break of tolerance to self-antigens that leads to organ-specific or systemic diseases often characterized by the presence of pathogenic autoreactive antibodies (AAb) produced by plasmablast and/or plasma cells. AAb are prevalent in the general population and not systematically associated with clinical symptoms. In contrast, in some individuals, these AAb are pathogenic and drive the development of signs and symptoms of antibody-mediated autoimmune diseases (AbAID). AAb production, isotype profiles, and glycosylations are promoted by pro-inflammatory triggers linked to genetic, environmental, and hormonal parameters. Recent evidence supports a role for pathogenic AAb of the IgE isotype in a number of AbAID. Autoreactive IgE can drive the activation of mast cells, basophils, and other types of FcεRI-bearing cells and may play a role in promoting autoantibody production and other pro-inflammatory pathways. In this review, we discuss the current knowledge on the pathogenicity of autoreactive IgE in AbAID and their status as therapeutic targets. We also highlight unresolved issues including the need for assays that reproducibly quantify IgE AAbs, to validate their diagnostic and prognostic value, and to further study their pathophysiological contributions to AbAID.

Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus and pemphigoid are two potentially life-threatening groups of autoimmune diseases, characterized by autoantibodies targeting structural components of desmosomes or hemidesmosomes, respectively. Affected patients typically show itchy/painful plaques or blistering skin lesions and/or impairing mucosal blistering and erosions, which may strongly impact their quality of life. Since the milestone work of Walter Lever in 1953, who differentiated these two groups of diseases by histopathological analysis of the level of antibody-mediated skin cleavage, enormous progresses occurred. Achievements made in laboratory diagnostics now allow to identify antigen specific structural proteins of the skin that are targeted by pathogenic autoantibodies. These progresses were accompanied by an increased understanding of the pathogenesis of these diseases thanks to the establishment of animal models reproducing disease and on studies on skin and blood of affected individuals, which have been leading to novel and disease-specific treatments. Yet, given their phenotypical overlap with more common dermatological diseases, correct diagnosis and appropriate treatment are often delayed, in some cases leading to irreversible sequelae, including organ dysfunction (i.e., loss of vision in mucous membrane pemphigoid). Here, we provide a concise overview of the clinical appearance, diagnosis and therapeutic management of pemphigus and pemphigoid diseases.

Pemphigus- und Pemphigoid-Erkrankungen: Klinik, Diagnostik und Therapie: Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus und Pemphigoid sind seltene Autoimmunkrankheiten der Haut mit potenziell lebensbedrohlichem Verlauf. Autoantikörper gegen epidermale und junktionale Strukturproteine (Desmosomen sowie Hemidesmosomen) führen bei Betroffenen typischerweise zu juckenden, schmerzhaften Plaques oder Blasen an der Haut und/oder Blasenbildung und Erosionen der Schleimhäute mit möglicher Einschränkung der Lebensqualität. Seit der bahnbrechenden Arbeit von Walter Lever im Jahr 1953, dem es gelang, mittels histopathologischer Untersuchung diese beiden Krankheitsgruppen anhand des Musters der Antikörper‐vermittelten Blasenbildung zu differenzieren, wurden enorme Fortschritte im Verständnis der Erkrankungen erzielt. Die Errungenschaften in der Labordiagnostik ermöglichten die Identifikation von Zielstrukturen zur präzisen Unterscheidung verschiedener Varianten der bullösen Autoimmunerkrankungen. Diese Fortschritte gingen dank der Entwicklung von Tiermodellen mit einem besseren Verständnis der Pathogenese einher. Außerdem haben Studien an Haut und Blut betroffener Patienten zu neuen und krankheitsspezifischen Behandlungen geführt. Aufgrund ihrer Seltenheit und der klinischen Ähnlichkeit mit anderen dermatologischen Erkrankungen verzögern sich die korrekte Diagnosestellung und die Einleitung einer entsprechenden Therapie häufig, was in einigen Fällen zu irreversiblen Folgeerscheinungen, einschließlich Funktionsstörungen von Organen (zum Beispiel Verlust des Sehvermögens beim Schleimhautpemphigoid) führt. Wir geben hier einen Überblick über das klinische Erscheinungsbild, den Diagnosealgorithmus und das therapeutische Management von Pemphigus‐ und Pemphigoid‐Erkrankungen.

Elevated levels of interleukin-9 in the serum of bullous pemphigoid: possible association with the pathogenicity of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease (sAIBD). In addition to disease causing autoantibodies, several leukocyte subsets, including mast cells and eosinophils, play key roles in mediating skin inflammation. Detailed immunophenotyping and, more recently, the therapeutic effects of interleukin-4 (IL-4) receptor alpha inhibition in BP pointed to a prominent role of T helper 2 (Th2) cells. Among other cell types, IL-9 is expressed by Th2 and mast cells and potentially drives allergic, Th2-dominated inflammation. Although cytokines in BP have been relatively well investigated, the role of IL-9 has remained enigmatic. This study aimed to evaluate the effect of IL-9 in BP. Serum IL-9 levels were significantly elevated in patients with BP and decreased upon induction of remission. Serum IL-9 levels were not elevated in epidermolysis bullosa acquisita, another sAIBD. The time-course analysis using serum sets from four patients with BP revealed that serum IL-9 was a sensitive biomarker of BP. IL-9-positive cells infiltrated dominantly in BP lesions, especially in the blister fluid, and Th9 cells were abundant. Therefore, IL-9 was elevated in the serum and lesions of BP, which could be a biomarker of BP.

Adaptive and innate immune pathogenesis of bullous pemphigoid: A review

Bullous pemphigoid (BP) is an autoimmune blistering disease that primarily affects elderly individuals. The presentation of BP is heterogeneous, typically manifesting as microscopic subepidermal separation with a mixed inflammatory infiltrate. The mechanism of pemphigoid development is unclear. B cells play a major role in pathogenic autoantibody production, and T cells, type II inflammatory cytokines, eosinophils, mast cells, neutrophils, and keratinocytes are also implicated in the pathogenesis of BP. Here, we review the roles of and crosstalk between innate and adaptive immune cells in BP.

Nine cases of refractory bullous pemphigoid treated with dupilumab and literature review

BACKGROUND AND AIMS

Bullous pemphigoid is an autoimmune blistering disease that affects the elderly mostly. First-line treatment of systemic corticosteroids may cause significant adverse effects, especially in patients with multiple co-morbidities. Dupilumab shows certain effectiveness in treating BP. We aim to profile our experience with dupilumab in a series of patients with BP and review the articles published to date.

METHODS

Medical records of 9 patients with moderate-to-severe BP were retrospectively reviewed. All patients were administered dupilumab. Response to dupilumab was evaluated by NRS scores, number of lesions, and the systemic corticosteroids' dosage. The PubMed, Embase, and Web of Science databases were searched to identify eligible studies.

RESULTS

The 9 patients were identified in this case series with a median age of 68 years (range 42-89) and the median duration of disease before being treated with dupilumab was 6 months (range 1-144). Complete remission was achieved in 6 patients while partial response was achieved in one patient. The NRS score had decreased to varying degrees at week 2 in all patients, and skin lesions improved within 2 to 6 weeks. Fifteen publications were included: 3 retrospective studies and 12 case series or reports, with a total of 63 patients. The overall complete response and partial response rates were 74.6 % and 11.1 %, respectively.

CONCLUSION

Dupilumab appears to be a safe alternative for the treatment of patients with refractory BP.

Bullous pemphigoid: The role of type 2 inflammation in its pathogenesis and the prospect of targeted therapy

Bullous pemphigoid (BP) is an autoimmune disease that mainly occurs in the elderly, severely affecting their health and life quality. Traditional therapy for BP is mainly based on the systemic use of corticosteroids, but long-term use of corticosteroids results in a series of side effects. Type 2 inflammation is an immune response largely mediated by group 2 innate lymphoid cells, type 2 T helper cells, eosinophils, and inflammatory cytokines, such as interleukin (IL)-4, IL-5 and IL-13. Among patients with BP, the levels of immunoglobulin E and eosinophils are significantly increased in the peripheral blood and skin lesions, suggesting that the pathogenesis is tightly related to type 2 inflammation. To date, various targeted drugs have been developed to treat type 2 inflammatory diseases. In this review, we summarize the general process of type 2 inflammation, its role in the pathogenesis of BP and potential therapeutic targets and medications related to type 2 inflammation. The content of this review may contribute to the development of more effective drugs with fewer side effects for the treatment of BP.

Licochalcone A inhibits IgE-mediated allergic reaction through PLC/ERK/STAT3 pathway

Licochalcone (LicA) is a flavonoid commonly derived from the licorice plant that is reported to have a variety of pharmacological activities. However, few studies have focused on its anti-allergic properties. IgE-mediated passive and systemic anaphylaxis mice models were used to assess the in vivo anti-allergic effect of LicA and its underlying mechanism, while degranulation, cytokines, and chemokines released from laboratory of allergic disease (LAD2) cells were used to assess its in vitro anti-allergic effect. We used western blot analysis to explore the downstream signaling pathway of its anti-allergic effect. We found that in the mouse model, LicA attenuated IgE-mediated paw inflammation, recovered the allergy-induced drop in body temperature, and reduced the concentrations of tumor necrosis factor-alpha and monocyte chemo-attractant protein-1 in mouse serum in a dose-dependent manner. LicA inhibited the allergic reaction via inhibition of IgE-mediated LAD2 cell activation through the PLC/ERK/STAT3 pathway.

Rituximab, Omalizumab, and Dupilumab Treatment Outcomes in Bullous Pemphigoid: A Systematic Review

Background

Bullous pemphigoid (BP) is the most common autoimmune subepidermal bullous disease of the skin. First-line treatment of systemic corticosteroids may cause serious adverse events. Rituximab, omalizumab, and dupilumab should be explored as alternative treatment options to improve outcomes.

Objective

To systematically review the rituximab, omalizumab, and dupilumab treatment outcomes in bullous pemphigoid.

Methods

A PubMed, Embase, Web of Science, and Cochrane library search were conducted on March 10, 2022. A total of 75 studies were included using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Results

Use of rituximab (n=122), omalizumab (n=53) and dupilumab (n=36) were reported in 211 patients with BP. Rituximab led to complete remission in 70.5% (n=86/122) and partial remission in 23.8% (n=29/122) of patients within 5.7 months, with a recurrence rate of 20.5% (n=25/122). 9.0% (n=11/122) of patients died and infection (6.6%, n=8/122) was the most common adverse event. Omalizumab led to complete remission in 67.9% (n=36/53) and partial remission in 20.8% (n=11/53) of patients within 6.6 months, with a recurrence rate of 5.7% (n=3/53). 1.9% (n=1/53) of patients died and thrombocytopenia (1.9%, n=1/53) was observed as the most common adverse event. Dupilumab led to complete remission in 66.7% (n=24/36) and partial remission in 19.4% (n=7/36) of patients within 4.5 months of treatment without any reported adverse events, with a recurrence rate of 5.6% (n=2/36).

Conclusions

Rituximab, omalizumab, and dupilumab have similar clinical benefits for BP patients. However, rituximab resulted in higher recurrence rates, adverse events, and mortality rates.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022316454.

Emerging Biomarkers and Therapeutic Strategies for Refractory Bullous Pemphigoid

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disorder in the elderly. Systemic and topical use of glucocorticoids and immunosuppressants has been shown to be effective in most patients. However, refractory BP patients are challenged to clinicians with severe clinical symptoms, resistance to treatment, and high relapse rate. How to predict and assess the refractory and severity of bullous pemphigoid is the key issue in clinical practice, and the urgent need for precision medicine in refractory patients is driving the search for biomarkers and biologics. Recently, some biomarkers, such as the level of specific autoantibodies and released cytokines, have been proposed as the potential parameters to reflect the disease severity and predict the treatment response and relapse of refractory BP. Moreover, new biologics targeting pathogenic antibodies, complement, Th2 axis, eosinophils, and Th17 axis have shown potent efficacy on refractory BP. Here, we review the literature and give an overview of emerging biomarkers and therapeutic strategies for refractory bullous pemphigoid to improve the prognosis of the patient.

BP230 IgE autoantibodies in topical-steroid-resistant bullous pemphigoid

BACKGROUND

IgE autoantibodies targeting BP230 can be identified in 38%-68% of bullous pemphigoid (BP) patients, yet the diagnostic and pathogenic value of anti-BP230 IgE still remains inconclusive.

OBJECTIVE

We intend to investigate the clinical and immunological characteristics of anti-BP230 IgE in BP patients.

METHODS AND RESULTS

Fifty-four BP patients were divided into two groups based on the responsiveness of a topical steroid. We investigated clinical features and IgE autoantibodies profiles by indirect immunofluorescence, ELISA and western blot between the two groups. BP disease area index (BPDAI) scores, total IgE, peripheral eosinophil counts, and anti-BP230 IgE level were significantly higher in the topical-steroid-resistant group. The majority of topical-steroid-resistant patients present with blister/erythematous phenotype (64.3%) and anti-BP230 IgE (59.5%), which correlates with total IgE levels. ELISAs of domain-specific BP230 recombinant proteins indicated that IgE in the topical-steroid-resistant group can react with all seven domains of BP230 and more frequently with the BP230-R1 epitope.

CONCLUSION

Anti-BP230 IgE is more frequently observed in topical-steroid-therapy-resistant patients and the prefers R1 domain of BP230, which is not included in commercially available testing kits. Our study further suggests the pathogenic role of anti-BP230 IgE in BP. Performing anti-BP230 IgE detection can serve as an indicator for initiating systemic steroid therapy.

IgE autoantibodies in serum and skin of non-bullous and bullous pemphigoid patients

BACKGROUND

Non-bullous pemphigoid (NBP) is a pemphigoid variant which frequently resembles other pruritic skin diseases. In contrast with bullous pemphigoid (BP), blisters are absent. In BP, previous studies showed that IgE autoantibodies may be involved in its pathogenesis. IgE-activated mast cells, basophils and eosinophils may participate in BP by inducing pruritus and possibly blister formation, although the differential role of IgE in NBP compared with BP has not yet been described.

OBJECTIVE

To assess IgE in serum and skin of NBP and BP patients.

METHODS

We examined total IgE and pemphigoid-specific IgE in the serum of 68 NBP and 50 BP patients by enzyme-linked immunosorbent assay (ELISA). Sera of 25 pemphigus patients and 25 elderly patients with pruritus were included as controls. Skin biopsies of 14 NBP and 14 BP patients with the highest IgE titres to NC16A were stained for IgE by immunofluorescence techniques.

RESULTS

Total IgE was elevated in 63% of NBP and 60% of BP patients, and in 20% of pemphigus controls, as well as 60% of elderly controls. IgE ELISAs were more frequently positive in BP than in NBP (NC16A 18% vs. 9%, P = 0.139; BP230 34% vs. 22%, P = 0.149). IgE ELISAs for NC16A and BP230 were positive in 8% and 20% of elderly controls, respectively, while all pemphigus controls were negative. Two of 28 biopsies (7%; one NBP, one BP) showed linear IgE along the basement membrane zone, while in most biopsies (71% NBP; 86% BP) IgE was bound to dermal cells.

CONCLUSION

Since IgE was present in the serum and skin of both NBP and BP patients, this supports IgE-dependent mechanisms common to both diseases, such as pruritus. However, it remains to be elucidated whether IgE contributes to blister formation in BP.