Effects of Omalizumab on FcεRI and IgE Expression in Lesional Skin of Bullous Pemphigoid

Efficacy of omalizumab for the treatment of bullous pemphigoid: Spanish multicentre real-world experience

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease. Most patients are older and have associated multiple comorbidities. Topical and systemic corticosteroids are considered the first-line treatment for BP, and immunosuppressants are used as steroid-sparing treatments. However, both have side-effects and contraindications, which are even more common in this older population. New treatments targeting interleukins and receptors related to BP pathogenesis have been proposed to decrease these side-effects while achieving equal or better effectiveness and response rates. Omalizumab is a monoclonal antibody that targets IgE and has been proposed for the treatment of BP due to the evidence that IgE autoantibodies play an essential role in BP pathogenesis.

OBJECTIVES

To assess the efficacy and safety of omalizumab for the treatment of BP.

METHODS

We carried out a multicentre, retrospective, observational study including patients diagnosed with BP who received omalizumab for ≥ 3 months from 15 tertiary hospitals in Spain. IgE levels prior to treatment were measured, and we evaluated the possible correlation with clinical response. We excluded patients treated with omalizumab for < 3 months, as we consider this duration to be insufficient for a comprehensive assessment of its efficacy. To evaluate the effectiveness of the treatment, we used the percentage of body surface area improvement.

RESULTS

We included 36 patients. The vast majority had associated multiple comorbidities, and all patients had used other systemic therapies apart from corticosteroids before omalizumab. In total, 83% experienced some kind of treatment response and 42% of all patients treated achieved complete response. We did not find any correlation between higher IgE levels and a better response (P = 0.2). All patients tolerated omalizumab without reported side-effects.

CONCLUSIONS

Omalizumab is a good therapeutic alternative for BP as it provided clinical response in most patients, and nearly one-half of the cases achieved complete response. It showed no side-effects, which is crucial in older patients with BP.

Omalizumab and Dupilumab for the Treatment of Bullous Pemphigoid: A Systematic Review

Background: Bullous pemphigoid (BP) is an autoimmune disease characterized by the appearance of very pruritic subepidermal blisters. It appears mostly in the elderly and is associated with multiple comorbidities, which makes its management and treatment difficult. The purpose of this systematic review is to compile current information on published cases of BP treated with omalizumab (omalizumab) and dupilumab (dupilumab) in order to obtain information on clinical efficacy and safety data available. Methods: A literature search of all cases of BP treated with omalizumab/dupilumab published in the literature up to January 2024 was performed using the Pubmed database. After an exhaustive search, a total of 61 studies encompassing 886 patients met the inclusion criteria and were included in the review. Results: The majority of patients with BP treated with omalizumab/dupilumab presented a significant improvement in symptomatology, being very safe drugs with minimal side effects. The main limitation of the presented review is the quality of the included studies, most of them being case series or individual cases. The development of studies with a higher level of scientific evidence in the near future would be of great interest. Conclusions: Both omalizumab and dupilumab appear to be effective options for treating BP in patients refractory to other pharmacological therapies. They are drugs with a good safety profile and the adverse reactions associated with their use are infrequent and generally mild.

[Spontaneous remission of urticaria: does it exist and if so, when?]

BACKGROUND

Urticaria mostly occurs acutely with a very high probability of spontaneous remission. When it persists for more than 6 weeks a chronic urticaria is manifest, which occurs either spontaneously or inducible by specific triggers. The underlying mechanisms are not fully understood but recent research points to defined pathogenetic factors.

QUESTION AND AIM

Whether spontaneous remission is possible in urticaria is summarized descriptively in this review, and suggestions are given for the "step down" of urticaria treatment after remission. The mechanisms including autoallergic, immunoglobulin E (IgE)-dependent type I reactions and autoimmune, activating IgG-dependent type IIb reactions are presented. These are discussed in the context of spontaneous remission and the possibilities of induced remission.

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.

Advancing Treatment in Bullous Pemphigoid: A Comprehensive Review of Novel Therapeutic Targets and Approaches

Bullous pemphigoid is one of the most common autoimmune bullous diseases occurring primarily in the elderly. Pathogenic autoantibodies against BP180 and BP230 at the dermal-epidermal junction cause subepidermal blisters, erosions, and intense pruritus, all of which adversely affect the patients' quality of life and may increase their morbidity and mortality. Current systemic treatment options for bullous pemphigoid are limited to corticosteroids and immunosuppressants, which can have substantial side effects on these vulnerable patients that even exceed their therapeutic benefits. Therefore, more precisely, targeting therapies to the pathogenic cells and molecules in bullous pemphigoid is an urgent issue. In this review, we describe the pathophysiology of bullous pemphigoid, focusing on autoantibodies, complements, eosinophils, neutrophils, proteases, and the T helper 2 and 17 axes since they are crucial in promoting proinflammatory environments. We also highlight the emerging therapeutic targets for bullous pemphigoid and their latest discoveries in clinical trials or experimental studies. Further well-designed studies are required to establish the efficacy and safety of these prospective therapeutic options.

Targeting type 2 inflammation in bullous pemphigoid: current and emerging therapeutic approaches

Bullous pemphigoid (BP) is one of the most common autoimmune bullous diseases and mainly affects an elderly population with multi-morbidity. Due to the frailty of many BP patients, existing treatment options are limited. The blisters associated with BP result from IgG and IgE autoantibodies binding to the central components of hemidesmosome, BP180, and BP230, stimulating a destructive inflammatory process. The known characteristic features of BP, such as intense pruritus, urticarial prodrome, peripheral eosinophilia, elevated IgE, as well as recent expanding evidence from in vitro and in vivo studies implicate type 2 inflammation as an important driver of BP pathogenesis. Type 2 inflammation is an inflammatory pathway involving a subset of CD4+ T cells that secrete IL-4, IL-5, and IL-13, IgE-secreting B cells, and granulocytes, such as eosinophils, mast cells, and basophils. It is believed that effectors in type 2 inflammation may serve as novel and effective treatment targets for BP. This review focuses on recent understandings of BP pathogenesis with a particular emphasis on the role of type 2 inflammation. We summarize current clinical evidence of using rituximab (B-cell depletion), omalizumab (anti-IgE antibody), and dupilumab (anti-IL-4/13 antibody) in the treatment of BP. The latest advances in emerging targeted therapeutic approaches for BP treatment are also discussed.

Basophils in pruritic skin diseases

Basophils are rare cells in the peripheral blood which have the capability to infiltrate into the skin. Invasion of basophils has been detected in pruritic skin diseases, including atopic dermatitis, bullous pemphigoid, chronic spontaneous urticaria and contact dermatitis. In the skin, basophils are important players of the inflammatory immune response, as they release Th2 cytokines, including interleukin (IL)-4 and IL-13, subsequently inducing the early activation of T-cells. Further, basophils release a multitude of mediators, such as histamine and IL-31, which both play an important role in the initiation of the pruritic response via activation of sensory nerves. Chronic pruritus significantly affects the quality of life and the working capability of patients, though its mechanisms are not fully elucidated yet. Since basophils and neurons share many receptors and channels, bidirectional interaction mechanisms, which drive the sensation of itch, are highlighted in this review.

Research progress of omalizumab in the treatment of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease associated with anti-BP180 and anti-BP230 antibodies. The pathogenic action mechanism of immunoglobulin E (IgE) antibodies in BP has been studied since the 1970s, and IgE antibodies have gradually been confirmed as being important in BP; therefore, anti-IgE therapy may be a new option for the treatment of BP. Omalizumab, as an IgE monoclonal antibody, has been increasingly used clinically to treat BP in recent years. Here, we collected 35 papers investigating omalizumab for BP treatment in a total of 83 patients, and the vast majority of patients showed varying degrees of improvement after treatment, except for a small number of patients with poor clinical outcomes. The patients were then divided into three groups according to dosing frequency and number of doses. Statistical analysis indicated that dosing frequency had little effect on clinical efficacy. While the groups with different numbers of doses were evaluated, the results concluded that clinical efficacy was affected by the number of doses, but there was no positive correlation between the number of doses and clinical efficacy.

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.

The cytokine milieu of bullous pemphigoid: Current and novel therapeutic targets

Bullous pemphigoid (BP) is the most common autoimmune bullous disease, characterized by severe pruritus and skin blistering. The loss of tolerance against Collagen XVII, also referred to as BP180, is the main pathogenic event of BP, leading to production of IgG autoantibodies which mainly target the juxtamembranous extracellular non-collagenous 16th A (NC16A) domain of BP180. A complex inflammatory network is activated upon autoantibody binding to the basement membrane zone; this inflammatory loop involves the complement cascade and the release of several inflammatory cytokines, chemokines and proteases from keratinocytes, lymphocytes, mast cells and granulocytes. Collectively, these events disrupt the integrity of the dermal-epidermal junction, leading to subepidermal blistering. Recent advances have led to identify novel therapeutic targets for BP, whose management is mainly based on the long-term use of topical and systemic corticosteroids. As an example, targeting type-2 T-helper cell-associated cytokines, such as Interleukin-4 and interleukin-13 has shown meaningful clinical efficacy in case series and studies; targeting IL-17 and IL-23 has also been tried, owing to an important role of these cytokines in the chronic maintenance phase of BP. In this review article, we discuss the complex cytokine milieu that characterized BP inflammation, highlighting molecules, which are currently investigated as present and future therapeutic targets for this life-threatening disease.

Recent Advances of Basophils in Pruritic Skin Diseases

Basophils are a rare type of granulocyte in peripheral blood. Owing to their accessibility in circulation and similarities to mast cells, basophils were considered a tool to gain insight into the function of mast cells. However, recent studies have uncovered that basophils have unique biology, specifically in activation, recruitment, and potential biomarkers. Accordingly, some previously unrecognized functions, particularly in neuroimmunology, have been found, suggesting a role of basophils in inflammatory and pruritic disorders. In this review, we aim to present an overview of basophil biology to show how basophils contribute to certain pruritic skin diseases.

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.

Biological treatment for bullous pemphigoid

Background

Bullous pemphigoid (BP) is the most common autoimmune subepidermal bullous disease. Topical or systemic corticosteroids are often used as the first-line treatment. However, long-term corticosteroid use may lead to significant side effects. Therefore, various adjuvant immunosuppressant therapies are used as steroid-sparing agents, with accumulating reports of biological treatments for severely recalcitrant BP.

Objective

To describe the clinical and immunological features of a series of patients with recalcitrant BP treated with immunobiological therapies. To assess the efficacy and safety of their therapies.

Methods

Patients receiving biological treatment for BP from two centers were assessed. Here, we described the clinical, immunopathological, and immunofluorescence findings of adult patients with BP and analyzed the clinical response and adverse events associated with various biological therapies.

Results

We identified nine eligible patients treated with rituximab (seven), omalizumab (three), or dupilumab (one). The mean age at diagnosis was 60.4 years, the average BP duration before biologic initiation was 1.9 years, and the average previous treatment failure was 2.11 therapies. The mean follow-up period from the first biological treatment to the last visit was 29.3 months. Satisfactory response, defined as clinical improvement, was achieved in 78% (7) of the patients, and total BP clearance was achieved in 55% (5) of the patients at the last follow-up visit. Additional rituximab courses improved the disease outcomes. No adverse events were reported.

Conclusions

Efficient and safe novel therapies can be considered in recalcitrant steroid-dependent BP non-responsive to conventional immunosuppressant therapies.

Case Report: Omalizumab Successfully Treated Recalcitrant Bullous Pemphigoid in an Elderly Patient with Multiple Comorbidities

Bullous pemphigoid (BP) is an autoimmune blistering disease mainly affecting elderly individuals. Comorbidities are common in patients with BP and have been found to complicate the management and prognosis. We describe a patient with multiple comorbidities who was successfully treated with omalizumab and suggest omalizumab as a good alternative therapy for BP to prevent treatment-related complications in elderly patients with a poor general condition.

Insights Into the Pathogenesis of Bullous Pemphigoid: The Role of Complement-Independent Mechanisms

Bullous pemphigoid is an autoimmune blistering disease caused by autoantibodies targeting BP180 and BP230. While deposits of IgG and/or complement along the epidermal basement membrane are typically seen suggesting complement -mediated pathogenesis, several recent lines of evidence point towards complement-independent pathways contributing to tissue damage and subepidermal blister formation. Notable pathways include macropinocytosis of IgG-BP180 complexes resulting in depletion of cellular BP180, direct induction of pro-inflammatory cytokines from keratinocytes, as well as IgE autoantibody- and eosinophil-mediated effects. We review these mechanisms which open new perspectives on novel targeted treatment modalities.

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.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Rapid Disease Control in First-Line Therapy-Resistant Mucous Membrane Pemphigoid and Bullous Pemphigoid with Omalizumab as Add-On Therapy: A Case Series Of 13 Patients

The role of IgE autoantibodies has been demonstrated in the pathogenesis of bullous pemphigoid for many years. Recently, omalizumab (OMZ), a humanized monoclonal anti-IgE antibody that depletes total serum IgE, has been used off-label in a few case series of bullous pemphigoids demonstrating a rapid efficacy and allowing significant improvements or complete remission as add-on therapy in first-line treatment-resistant patients. Herein, we report the largest retrospective study to evaluate OMZ effectiveness in patients with subepidermal autoimmune blistering diseases. Our series included 13 patients from a single center with bullous pemphigoid or mucous membrane pemphigoid, of whom 7 had mucous membrane involvement. OMZ was added to the unchanged immunosuppressive therapies. Detailed clinical and immunological data during the first year were collected, notably for specific anti-BP180-NC16A IgE and IgG, and the median total follow-up was 30 months (range: 3-81). Our series demonstrated that OMZ induced a significant improvement in pruritus, urticarial score, and daily blister count on day 15, allowing disease control to be achieved in a 1-month median time and complete remission (CR) in a 3-month median time in 85% of these patients previously in therapeutic impasse. At the end of the follow-up, 31% of patients achieved CR on minimal therapy after OMZ weaning without relapses, and 54% achieved CR on OMZ continuation with a minimal dose of concomitant treatment. Two patients experienced therapeutic failure (15%). At baseline, clinical variables reflecting activity were significantly positively correlated with eosinophil blood count, total IgE serum level, specific anti-BP180 IgE and IgG. While baseline anti-BP180 IgG and specific anti-BP180 IgE were significantly positively correlated, only the two patients who experienced a therapeutic failure with OMZ did not fit with this correlation, demonstrating elevated levels of anti-BP180 IgG with no measurable BP180-specific IgE. Follow-up of immunological variables demonstrated a rapid decrease of eosinophilia towards normalization, whereas a slower decline towards negativation was observed over 1 year for anti-BP180 IgG and anti BP180 IgE in patients who responded to OMZ. This case series demonstrated that OMZ is a rapidly effective biologic therapy for refractory bullous pemphigoid and mucous membrane pemphigoid, permitting rapid disease control and reduction of concomitant therapeutics.

Controversies in Allergy: The Potential Role of Biologics as First-Line Therapy in Eosinophilic Disorders

With advances in understanding the role of eosinophils in disease pathogenesis, particularly in the airways, gastrointestinal tract, and skin, targeting eosinophils or the cytokines that lead to their production, activation, and survival has become an increasingly pursued therapeutic approach. Newly developed biologic agents target eosinophils directly, other cells interacting with or activating eosinophils, or cytokines in the type 2 inflammatory pathway with specific antibodies. Current treatment paradigms reserve therapy with biologics for patients refractory to or intolerant of corticosteroids or immunosuppressants. Given accumulating data for safety and efficacy of these biologics, however, there is the question of whether targeted treatments should be used earlier in the treatment algorithm. In this article, we discuss the pros and cons of using biologics as first-line therapy for eosinophilic diseases of the airways, gastrointestinal tract, and skin. We highlight emerging biologic agents and future directions for research, as well as a rationale for the early use of some biologics to prevent tissue damage, disease progression, and organ dysfunction in selected conditions.

Omalizumab for the Treatment of Bullous Pemphigoid: A Systematic Review of Efficacy and Safety

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Current treatment strategies are limited by their efficacy and/or side effect profile and the need for safer and effective alternatives is undeniable. We aimed to conduct a systematic review focusing on the efficacy and safety of omalizumab in BP patients. Embase, PubMed, Cochrane, and clinicaltrials.gov were searched for English and French articles published from inception to July 1, 2021, using search terms "omalizumab" OR "Xolair" OR "IGE025" OR "olizumab" AND "bullous pemphigoid." Screening and data extraction was performed by two raters independently. The primary outcome was complete response (CR), and secondary outcomes were partial response (PR), flare-ups, adverse events/vital status. In total, 22 articles were included, with a total of 56 patients. All patients had a refractory BP with mean disease duration of 13.5 ± 20.2 months (Standard Deviation (SD)) and failed 3.1 ± 1.6 therapies and many remained corticosteroids dependent. Overall, 87.5% of patients responded to treatment (55.4% CR and 32.1% PR), 7.1% discontinued the protocol and only 5.4% were non responders. A third of patients were able to discontinue all other therapies and most others were able to discontinue or taper systemic corticosteroids to <10 mg daily. Flare-ups occurred in 57.7% of patients upon discontinuation of omalizumab and/or steroid tapering, most patients recaptured response thereafter. Omalizumab was well tolerated by most patients. Omalizumab appears to be a promising treatment for BP with a good response rate and safety profile. However, several limitations were identified in current literature, and highlight the need for randomized controlled trials of omalizumab in BP.

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.

Case Report: Combination of Omalizumab and Dupilumab for Recalcitrant Bullous Pemphigoid

Bullous pemphigoid (BP) is a blistering autoimmune skin disease. Omalizumab, a monoclonal antibody directed to IgE, showed a beneficial effect in treatment of recalcitrant BP in case series. More recently, dupilumab, an interleukin (IL)-4-receptor alpha antagonist, also showed promising preliminary results. We describe a patient with refractory BP who showed a complete response to a combination therapy with omalizumab and dupilumab.

Dramatic improvement of bullous pemphigoid with omalizumab in an elderly patient

A 70-year-old man with a history of hypertension was evaluated in our dermatology department due to the appearance of a clinical picture compatible with bullous pemphigoid that was confirmed histologically. The lack of response to topical and systemic immunosuppressive treatment resulted in omalizumab being prescribed in a multidisciplinary committee based on the clinical and analytical findings and the patient's refusal to be treated with rituximab. The evaluation at 3 months showed the absence of blisters on the clinical examination. No associated adverse effects were observed. In the following 3 months the patient was administered medication at home in the absence of an anaphylactic reaction and with prior training by the nursing staff of the Hospital Pharmacy Service. After 6 months the medication was suspended with no relapses for 6 months since the last dose. Omalizumab, an anti-IgE monoclonal drug which has a good safety profile with minimum adverse side effects should be considered when there is a contraindication to the use of intravenous therapies (eg, immunoglobulins, rituximab) or prolonged immunosuppressive treatment (eg, methotrexate, azathioprine).

Total IgE, eosinophils, and interleukins 16, 17A, and 23 correlations in severe bullous pemphigoid and treatment implications

Bullous pemphigoid (BP) patients are predominantly above 70 years of age, with limited tolerance to the side effects of the immunosuppressive drugs. Advancements in our understanding of the pathophysiology of BP have led to the development of molecules which target specific pathways involved in induction and perpetuation of disease. Patients with BP Disease Area Index above 60 and less than 100 were split into two groups-one with high and the other with normal levels of IgE. The tested parameters included eosinophils' count, total IgE serum level, and interleukins (IL) 16, 17A, and 23 counts in the peripheral blood and skin bulla serum, before any therapeutic intervention. Thirty individuals fulfilled the criteria for enrollment. Patients with high IgE blood serum levels had significantly higher levels of IL17A and normal IL23 levels in blood and bulla serum. Patients with normal serum IgE levels had slightly higher IL23 levels in blood and bulla serum. The eosinophil count was positively related to IL17 blood serum level and negatively related to IL23. IL16 did not differ in the two groups. BP patients may represent a group of patients benefiting most substantially from the introduction of nonimmunosuppressive therapeutics into the treatment regimens for their disease. Clinical criteria and immune biomarkers are needed for making the best therapeutic choice.

Pemphigus Vulgaris and Bullous Pemphigoid: Update on Diagnosis and Treatment

Autoimmune bullous disorders are a heterogeneous spectrum of skin disorders characterized by the production of autoantibodies against adhesion molecules of the skin. The 2 major groups of diseases are "pemphigus diseases" and "autoimmune bullous diseases of the pemphigoid type." Pemphigus diseases are a group of autoimmune blistering diseases of the skin and mucous membranes characterized by intraepithelial cleft and acantholysis. The main subtypes of pemphigus include pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus. Diagnosis is based on clinical manifestations and confirmed with histological, immunofluorescence, and serological testing. Recently multivariant enzyme-linked immunosorbent assay systems have been developed as practical screening tools for patients with suspected autoimmune bullous dermatoses. The current first-line treatment of pemphigus is based on systemic corticosteroids that are often combined with immunosuppressive adjuvants, such as azathioprine, mycophenolate mofetil, and the anti-CD20 monoclonal antibody rituximab, usually at initiation of treatment. Rituximab efficacy is higher when it is administered early in the course of the disease. Therefore, it should be used as first-line treatment to improve efficacy and reduce cumulative doses of corticosteroids and their side effects. Treatment of bullous pemphigoid is based on disease extension. Localized and mild forms can be treated with superpotent topical corticosteroids or with nonimmunosuppressive agents. In patients with generalized disease or whose disease is resistant to the treatments described above, systemic corticosteroids are preferred and effective. Adjuvant immunosuppressants are often combined with steroids for their steroid-sparing effect.

Eosinophils in Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disorder with substantial morbidity and mortality. BP is regarded as a disorder driven by IgG due to BP180 and BP230 IgG autoantibodies, yet, new advances highlight the function of eosinophils and IgE autoantibodies in BP. Evidence supports that eosinophils are involved in BP pathogenesis, notably, these include the presence of IL-5, eotaxin, and eosinophil-colony stimulating factor in blister fluid, peripheral blood eosinophilia is present in nearly 50% of affected patients, eosinophils are found against the dermo-epidermal junction (DEJ) when BP serum is present, metalloprotease-9 is secreted by eosinophils at blister sites, blister fluid of BP patients contains eosinophil granule proteins which are located along the lamina lucida of the BMZ in patients with BP and correspond with disease clinically, eosinophil extracellular traps (EET) have been linked to DEJ splitting, IL-5 activated eosinophils cause DEJ separation when BP serum is present, and eosinophils are requisite to drive anti-BP180 IgE mediated blistering of the skin. Yet, the mechanism whereby eosinophils contribute to the pathogenesis of BP remains to be explored. In this review, we examine the role of eosinophils in BP while offering a basis to explain the pathomechanisms of eosinophils in BP.

The Expression and Function of CD300 Molecules in the Main Players of Allergic Responses: Mast Cells, Basophils and Eosinophils

Allergy is the host immune response against non-infectious substances called allergens. The prevalence of allergic diseases is increasing worldwide. However, while some drugs counteract the symptomatology caused by allergic reactions, no completely effective treatments for allergic diseases have been developed yet. In this sense, the ability of surface activating and inhibitory receptors to modulate the function of the main effector cells of allergic responses makes these molecules potential pharmacological targets. The CD300 receptor family consists of members with activating and inhibitory capabilities mainly expressed on the surface of immune cells. Multiple studies in the last few years have highlighted the importance of CD300 molecules in several pathological conditions. This review summarizes the literature on CD300 receptor expression, regulation and function in mast cells, basophils and eosinophils, the main players of allergic responses. Moreover, we review the involvement of CD300 receptors in the pathogenesis of certain allergic diseases, as well as their prospective use as therapeutic targets for the treatment of IgE-dependent allergic responses.