Successful management of severe infant bullous pemphigoid with omalizumab

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.

The Eotaxin-1/CCR3 Axis and Matrix Metalloproteinase-9 Are Critical in Anti-NC16A IgE-Induced Bullous Pemphigoid

Bullous pemphigoid (BP) is the most common autoimmune bullous skin disease of humans and is characterized by eosinophilic inflammation and circulating and tissue-bound IgG and IgE autoantibodies directed against two hemidesmosomal proteins: BP180 and BP230. The noncollagenous 16A domain (NC16A) of BP180 has been found to contain major epitopes recognized by autoantibodies in BP. We recently established the pathogenicity of anti-NC16A IgE through passive transfer of patient-derived autoantibodies to double-humanized mice that express the human high-affinity IgE receptor, FcεRI, and human NC16A domain (FcεRI/NC16A). In this model, anti-NC16A IgEs recruit eosinophils to mediate tissue injury and clinical disease in FcεRI/NC16A mice. The objective of this study was to characterize the molecular and cellular events that underlie eosinophil recruitment and eosinophil-dependent tissue injury in anti-NC16A IgE-induced BP. We show that anti-NC16A IgEs significantly increase levels of key eosinophil chemoattractants, eotaxin-1 and eotaxin-2, as well as the proteolytic enzyme matrix metalloproteinase-9 (MMP-9) in the lesional skin of FcεRI/NC16A mice. Importantly, neutralization of eotaxin-1, but not eotaxin-2, and blockade of the main eotaxin receptor, CCR3, drastically reduce anti-NC16A IgE-induced disease activity. We further show that anti-NC16A IgE/NC16A immune complexes induce the release of MMP-9 from eosinophils, and that MMP-9-deficient mice are resistant to anti-NC16A IgE-induced BP. Lastly, we find significantly increased levels of eotaxin-1, eotaxin-2, and MMP-9 in blister fluids of BP patients. Taken together, this study establishes the eotaxin-1/CCR3 axis and MMP-9 as key players in anti-NC16A IgE-induced BP and candidate therapeutic targets for future drug development and testing.

Anti-interleukin 4 receptor α antibody for the treatment of Chinese bullous pemphigoid patients with diverse comorbidities and a 1-year follow-up: a monocentric real-world study

Background

Bullous pemphigoid (BP) is a common subepidermal bullous disorder that lacks adequate treatment alternatives. Dupilumab, an anti-interleukin (IL) 4 receptor α antibody blocking Th2 molecules IL-4 and 13, has been used off-label and shown to be effective in refractory BP cases.

Methods

BP patients with various disease severities and comorbidities were included in this case series. All patients received dupilumab alone or in combination with immunosuppressants in a real-world setting. Complete remission (CR) was defined as the absence of pruritus symptoms and previous BP eruptions, with only hyperpigmentation patches and without newly occurring lesions for at least 4 weeks. Disease relapse was classified as the appearance of three or more new lesions within 1 month or at least one large urticarial or eczematous lesion that did not resolve within a week.

Findings

Ten individuals were enrolled in this case series. Pruritus symptoms and BP eruptions improved significantly in nine patients (90%). Seven patients (70%) attained CR, including all mild-to-moderate (100%) cases and three of six (50%) severe BP cases. At the dupilumab monotherapy stage, eosinophilia was observed in two severe cases. One patient out of seven (14.3%) relapsed after 1 year of follow-up after CR.

Conclusion

Treatment of BP with diverse comorbidities with anti-IL-4 receptor α antibody provides further credentials to a prospective randomized study. More impressive efficacy and safety profiles were observed in patients with mild-to-moderate disease after 1 year of follow-up. Eosinophilia may occur in patients receiving dupilumab monotherapy.

Association between bullous pemphigoid and atopic dermatitis: a population-based case-control study in Taiwan

Although bullous pemphigoid (BP) and atopic dermatitis (AD) share pathogenic mechanisms, their relationship remains controversial. Therefore, we conducted a population-based case-control study to investigate the association between BP and AD in Taiwan. Based on the Taiwan National Health Insurance Research Database, 9344 patients with BP and 18,688 age- and sex-matched controls were enrolled between 2000 and 2013. Furthermore, the study included 7,196 BP patients and 14,392 controls, matched for age, sex, and propensity score of comorbidities, with a case to controls ratio of 1:2. Logistic regression analysis was performed to examine the association between AD and BP. In the age- and sex-matched cohorts, AD (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.50-1.95) was independently associated with BP. In the age, sex, and comorbidities-matched cohorts, AD (OR 1.76, 95% CI 1.55-2.00) remained a significant risk factor for BP. Other significant risk factors included psoriasis, hypertension, diabetes mellitus, chronic kidney disease, chronic obstructive pulmonary disease, neuropsychiatric diseases, and autoimmune connective tissue disease. Limitations of this study include the lack of information on disease severity and phenotypes of BP and misclassification of diseases as potential sources of bias. In conclusion, AD increased the risk of developing BP by 76%, and this association was independent of many BP comorbidities. Further studies are warranted to investigate the clinical and pathophysiological relevance of factors contributing to BP and AD.

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.

Self-reactive IgE and anti-IgE therapy in autoimmune diseases

Growing evidence indicates the pathogenic role of autoreactive IgE in autoimmune diseases. Incidence of autoimmune and allergic diseases in the industrialized countries is consistently icreasing, thus leading to concerted efforts to comprehend the regulation of IgE-mediated mechanisms. The first reports of a presence of IgE autoantibodies in patients with autoimmune diseases have been published a long time ago, and it is now recognized that self-reactive IgE can mediate inflammatory response in bullous pemhigoid, systemic lupus erythematosus, chronic urticaria, and atopic dermatitis. The advances in understanding the pathomechanisms of these disorders brought to a successful use of anti-IgE strategies in their management. The present review discusses the current state of knowledge on the IgE-mediated autoimmunity and anti-IgE treatment, and pave the way for further exploration of the subject.

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.

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.

Efficacy and Safety of Dupilumab in Moderate-to-Severe Bullous Pemphigoid

Background

Bullous pemphigoid (BP) is an autoimmune blistering disorder that predominantly affects the elderly. As the main treatment for BP, systemic corticosteroids are often limited by their side effects. Safer treatment modalities are therefore needed. Dupilumab is a biologic agent used to treat BP in recent years.

Methods

Medical records of patients with moderate-to-severe BP were retrospectively reviewed. Twenty-four patients were included (follow-up period: 32 weeks), eight of whom received dupilumab in combination with methylprednisolone and azathioprine (dupilumab group) while the other 16 patients received methylprednisolone and azathioprine (conventional group). Response to dupilumab was evaluated by comparison of several parameters (time to stop new blister formation, time to reduce the systemic glucocorticoids to minimal dose, and total amount of methylprednisolone).

Results

The median age of patients in the dupilumab and conventional groups were 64.50 years (range: 22–90 years) and 64.50 years (range: 17–86 years), respectively. The median duration of disease before admission in the dupilumab group was 2 months (range: 1–240 months) and 2.5 months (range: 1–60 months) in the conventional group. The median time to stop new blister formation was 8 days (range: 1–13 days) and 12 days (range: 5–21 days) in patients of the dupilumab and conventional groups, respectively (p = 0.028 by Kaplan-Meier analysis). In addition, the median time to reduce the systemic glucocorticoids to minimal dose (methylprednisolone 0.08 mg/kg/day) was 121.5 and 148.5 days for the dupilumab and conventional therapy groups, respectively (p = 0.0053 by Kaplan-Meier analysis). The median total amount of methylprednisolone (at the time of reaching the minimal dose) used in the dupilumab group was 1,898 mg (range: 1,624–2,932 mg) while the cumulative dose of conventional group was 2,344 mg (range: 1,708–4,744 mg) (p = 0.036 by Mann-Whitney U test). The median total amount of azathioprine (at the time of reaching the minimal dose) used in dupilumab group was 8,300 mg (range: 7,100–10,400 mg) while the total dose of conventional group was 10,300 mg (range: 8,900–14,400 mg) (p = 0.0048 by Mann-Whitney U test). No adverse event related to dupilumab was recorded.

Conclusions

Dupilumab in addition to methylprednisolone and azathioprine seems superior to methylprednisolone/azathioprine alone in controlling disease progression and accelerating the tapering of glucocorticoids.

Biologics in autoimmune bullous diseases: Current scenario

Autoimmune bullous diseases can be intraepidermal (pemphigus group of disorders) or subepidermal (pemphigoid group of disorders). The treatment of these disorders chiefly comprises corticosteroids and immunosuppressant adjuvants like azathioprine and mycophenolate mofetil. Autoantibodies are the main mediators of these diseases. Rituximab, a chimeric anti-CD20 monoclonal antibody targeting B-cells, has emerged as an excellent treatment option for refractory pemphigus vulgaris in the last decade. Since then, many new biologics have been proposed/explored for managing autoimmune bullous diseases. These hold potential for greater efficacy and lesser adverse effects than conventional immunosuppressants. In this review, we discuss the role of various biologics in the treatment of autoimmune bullous diseases, followed by a brief discussion on the drawbacks to their use and new developments in this area.

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.

Complete Remission in a Patient with Treatment Refractory Bullous Pemphigoid after a Single Dose of Omalizumab

Bullous pemphigoid (BP) is an autoimmune disorder known to be mediated by immunoglobulin G (IgG) autoantibodies. The role of immunoglobulin E (IgE) antibodies is being investigated as their presence has been described in severe cases. Herein, we report a patient of BP who was refractory to most conventional agents and developed hypotension after rituximab but achieved lasting remission after a single dose of the anti-IgE monoclonal antibody omalizumab.

Factors associated with the activity and severity of bullous pemphigoid: a review

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease. It usually affects people older than 70 years of age. The two main autoantigens are BP180 and BP230, both of which are components of hemidesmosomes. Immunoglobulin (Ig)G and IgE autoantibodies to BP180 detected by the enzyme-linked immunoassay (ELISA) show close associations with the activity and severity of BP. In addition, inflammatory cells (eosinophils, neutrophils and mast cells) and cytokines (e.g. interleukins and CC chemokine ligands) play an important part in the pathogenesis, activity and severity of BP. We summarized the potential contribution of each factor postulated to be associated with the activity and severity of BP, and provide guidance for clinicians to pay timely and close attention to such parameters. This review may also promote the development of novel therapies for BP.Key MessagesBullous Pemphigoid Disease Area Index (BPDAI) is a scoring system which can reflect the extent of clinical involvement of BP patients.The titres of IgE autoantibodies and IgG autoantibodies against the NC16A domain of BP180 are closely correlated with the activity and severity of BP.Many inflammatory cells and molecules, such as eosinophils and interleukins, can also reflect the activity and severity of BP.

The Intersection of IgE Autoantibodies and Eosinophilia in the Pathogenesis of Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by autoantibodies targeting cellular adhesion molecules. While IgE autoantibodies are occasionally reported in other autoimmune blistering diseases, BP is unique in that most BP patients develop an IgE autoantibody response. It is not known why BP patients develop self-reactive IgE and the precise role of IgE in BP pathogenesis is not fully understood. However, clinical evidence suggests an association between elevated IgE antibodies and eosinophilia in BP patients. Since eosinophils are multipotent effector cells, capable cytotoxicity and immune modulation, the putative interaction between IgE and eosinophils is a primary focus in current studies aimed at understanding the key components of disease pathogenesis. In this review, we provide an overview of BP pathogenesis, highlighting clinical and experimental evidence supporting central roles for IgE and eosinophils as independent mediators of disease and via their interaction. Additionally, therapeutics targeting IgE, the Th2 axis, or eosinophils are also discussed.

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

Recent studies suggest an important role of immunoglobulin E (IgE) as an alternative pathogenic pathway in the development of bullous pemphigoid (BP), as the most frequent subepidermal blistering disease of the skin Use of IgE targeted therapies, such as omalizumab, has been shown promising in recent studies. The aim of this study was to assess the effect of omalizumab on FcεRI and IgE expression on circulating basophils and on lesional intradermal cells in BP to generate insight into the immunological effects of omalizumab in BP. We report two cases of BP patients treated with omalizumab. Efficacy of treatment was assessed clinically 4 months after initiation of the therapy. Lesional and non-lesional skin biopsies where taken before and 4 weeks after initiation of omalizumab therapy. In addition, FcεRI expression on circulating cells and IgE levels in serum and in the skin samples, as well as anti-BP180 and anti-BP230 in serum and eosinophils and basophils counts in blood were assessed before and during treatment. Both patients showed a marked improvement after 4 months, with no adverse effects. Down-regulation of FcεRI, IgE in lesional skin and on circulating basophils were observed in parallel with clinical improvement. The current case study supports the role of omalizumab in the treatment of a subset of BP patients. Our observations suggest that omalizumab represents a valuable therapeutic option in the management of BP patients. Its efficacy might be related to reduction in FcεRI+ and IgE+ basophils and intradermal cells.

Role of the Pruritic Cytokine IL-31 in Autoimmune Skin Diseases

Many autoimmune skin diseases, such as bullous pemphigoid (BP), psoriasis and certain types of chronic urticaria, are associated with intensive pruritus. While histamine and neuropeptides have previously been ascribed to play a role in itch that accompanies these diseases, recent evidence suggests that the pruritogenic cytokine interleukin (IL)-31 is a major driver of pruritic responses. IL-31 was originally shown to be produced by activated helper T cells, particularly Th2 cells, mast cells, macrophages and dendritic cells. However, more recent evidence demonstrated that eosinophils are a major source of this cytokine too, particularly in bullous pemphigoid. Basophils have also been shown to express the cytokine which, through autocrine action, strongly supports the production of other Th2-type cytokines from these cells. These investigations suggest that the dynamic recruitment of eosinophils and basophils in some autoimmune skin diseases could play an important role in the severity of IL-31-mediated itch. Furthermore, these studies suggest that IL-31, in addition to its pruritic actions, also has potential immunomodulatory roles in terms of supporting Th2-type immunity, which often underpins IgE-associated autoimmune diseases (such as bullous pemphigoid and urticaria) as well as allergies. While the role of IL-31 in psoriasis remains to be clarified, current evidence shows that this cytokine plays a major role in BP, chronic spontaneous urticaria and dermatomyositis. This suggests potential use of IL-31 receptor-blocking therapeutic approaches (e.g., Nemolizumab) for the treatment of IL-31-associated disorders.

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

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering skin disease worldwide. Systemic corticosteroids are considered the mainstay of therapy; however, they may cause significant adverse effects and treatment failures, so additional therapeutic modalities with better safety profiles are required. Rituximab and omalizumab are novel biologic agents administered in recent years for the treatment of BP, yet data regarding their use in the disease are limited.

OBJECTIVE

Our objective was to systematically review the current literature regarding the use of rituximab and omalizumab for the treatment of BP to evaluate their safety and efficacy.

METHODS

A systematic review of all publications evaluating patients with BP treated with rituximab or omalizumab was performed. The primary outcome was clinical response; secondary outcomes were adverse events and recurrence rate.

RESULTS

The systematic review included 35 publications (84 patients: 62 receiving rituximab and 22 receiving omalizumab). In total, 61 of 63 patients had not experienced disease control with systemic corticosteroids before receiving the biologic treatment. Complete response rates were 85% and 84% for rituximab and omalizumab, respectively. The recurrence rate was considerably lower with rituximab (29%) than with omalizumab (80%). Mean time to recurrence was 10.2 and 3.4 months, and adverse effects occurred in 24% and 20% of the patients, respectively.

CONCLUSIONS

Available data, although potentially limited because of publication bias, suggest that rituximab and omalizumab have similar safety profiles and provide clinical benefit for patients with BP. The reviewed data indicated that rituximab resulted in lower recurrence rates and a longer time until recurrence than omalizumab.

Omalizumab as an alternative therapeutic tool in the treatment of bullous pemphigoid: A case report

Bullous pemphigoid (BP) is an acquired autoimmune bullous disease characterized by autoantibodies against the hemidesmosomal proteins found in the basal keratinocytes of the basement membrane zone (BMZ): a 180 kDa protein (type XVII collagen) mainly and the 230 kDa antigen. There is such evidence that the antibodies against the BMZ components are not only of IgG type, but also this bullous disease may have IgE antibodies directed to the BMZ that contribute to the pathogenesis of the disorder. IgE is not only thought to contribute to the pathogenesis of BP, it has also been suggested that eosinophils play a role in the development of the first signs associated with BP. A humanized monoclonal antibody directed to IgE, omalizumab, is approved for the treatment of severe asthma and chronic spontaneous urticaria, and it may be useful in the treatment of BP in the first stages of the disease.

The Role of Eosinophils in Bullous Pemphigoid: A Developing Model of Eosinophil Pathogenicity in Mucocutaneous Disease

Bullous pemphigoid (BP) is an autoimmune blistering disease which carries a significant mortality and morbidity. While historically BP has been characterized as an IgG driven disease mediated by anti-BP180 and BP230 IgG autoantibodies, developments in recent years have further elucidated the role of eosinophils and IgE autoantibodies. In fact, eosinophil infiltration and eosinophilic spongiosis are prominent features in BP. Several observations support a pathogenic role of eosinophils in BP: IL-5, eotaxin, and eosinophil-colony stimulating factor are present in blister fluid; eosinophils line the dermo-epidermal junction (DEJ) in the presence of BP serum, metalloprotease-9 is released by eosinophils at the site of blisters; eosinophil degranulation proteins are found on the affected basement membrane zone as well as in serum corresponding with clinical disease; eosinophil extracellular DNA traps directed against the basement membrane zone are present, IL-5 activated eosinophils cause separation of the DEJ in the presence of BP serum; and eosinophils are the necessary cell required to drive anti-BP180 IgE mediated skin blistering. Still, it is likely that eosinophils contribute to the pathogenesis of BP in numerous other ways that have yet to be explored based on the known biology of eosinophils. We herein will review the role of eosinophils in BP and provide a framework for understanding eosinophil pathogenic mechanisms in mucocutaneous disease.

Treatment of Autoimmune Bullous Disorders in Pregnancy

Autoimmune bullous diseases (AIBD), including pemphigus, bullous pemphigoid, epidermolysis bullosa acquisita, mucous membrane pemphigoid, and pemphigoid gestationis, pose significant therapeutic challenges, especially in pregnant and post-partum breastfeeding patients or those planning to conceive. Data on the safety and efficacy of therapeutic interventions during the perinatal period are lacking because randomized controlled trials are typically not performed in this setting. However, many of the treatments for AIBD are also used in other diseases, so data can be extrapolated from studies or case reports in these other patient populations. It appears that many of the treatments for AIBD can adversely affect the fetus or neonate, and alterations in immune status caused by pregnancy-associated hormonal changes can negatively impact disease control. This article summarizes and weighs the risks and benefits of the various agents used to treat AIBD during pregnancy. We also present the available information on lactation as well as effects on male fertility.

Immunoglobulin E-Mediated Autoimmunity

The study of autoimmunity mediated by immunoglobulin E (IgE) autoantibodies, which may be termed autoallergy, is in its infancy. It is now recognized that systemic lupus erythematosus, bullous pemphigoid (BP), and chronic urticaria, both spontaneous and inducible, are most likely to be mediated, at least in part, by IgE autoantibodies. The situation in other conditions, such as autoimmune uveitis, rheumatoid arthritis, hyperthyroid Graves’ disease, autoimmune pancreatitis, and even asthma, is far less clear but evidence for autoallergy is accumulating. To be certain of an autoallergic mechanism, it is necessary to identify both IgE autoantibodies and their targets as has been done with the transmembrane protein BP180 and the intracellular protein BP230 in BP and IL-24 in chronic spontaneous urticaria. Also, IgE-targeted therapies, such as anti-IgE, must have been shown to be of benefit to patients as has been done with both of these conditions. This comprehensive review of the literature on IgE-mediated autoallergy focuses on three related questions. What do we know about the prevalence of IgE autoantibodies and their targets in different diseases? What do we know about the relevance of IgE autoantibodies in different diseases? What do we know about the cellular and molecular effects of IgE autoantibodies? In addition to providing answers to these questions, based on a broad review of the literature, we outline the current gaps of knowledge in our understanding of IgE autoantibodies and describe approaches to address them.

IgE autoantibodies and their association with the disease activity and phenotype in bullous pemphigoid: a systematic review

Bullous pemphigoid (BP) is the most common autoimmune skin disease of blistering character. The underlying pathophysiological mechanism involves an immune attack, usually by IgG class autoantibodies, on the autoantigen BP 180/BPAg2, which is a type XVII collagen (COL17) protein acting as the adhesion molecule between the epidermis and the basement membrane of the dermis. About 40 years ago, following consistent findings of elevated total serum IgE levels in BP patients, it was hypothesized that IgE may be involved in the pathophysiology of BP. Our objective was to determine whether there is strong evidence for an association between IgE class autoantibodies and the clinical severity or phenotype of BP. Three databases were searched for relevant studies and appropriate exclusion and inclusion criteria were applied. Data was extracted and assessed in relation to the study questions concerning the clinical significance of IgE autoantibodies in BP. Nine studies found that anti-BP180 autoantibodies of IgE class are associated with increased severity of BP, whereas two studies did not find such an association. The number of studies which found an association between higher IgE autoantibody levels and the erythematous urticarial phenotype of BP (5) was equal in number to the studies which found no such association (5). In conclusion, higher serum IgE autoantibody levels are associated with more severe clinical manifestations of BP. There is insufficient evidence to support higher IgE autoantibody levels being associated with specific clinical phenotypes of BP.

Successful Treatment of a Bullous Pemphigoid Patient with Rituximab Who Was Refractory to Corticosteroid and Omalizumab Treatments

Omalizumab is a humanized monoclonal antibody which is an FDA-approved treatment of severe allergic asthma and inhibits IgE binding to FcεRI. According to increasing evidence of IgE inhibition, omalizumab was suggested as a therapeutic approach for bullous pemphigoid (BP). Rituximab has been reported to be effective in various autoimmune diseases, including autoimmune bullous dermatoses. A specific protocol for the use of rituximab to treat BP patients is not yet available. There are only small case series and case reports about the efficacy and safety of rituximab in BP. Here we present a young BP patient who responded well to rituximab therapy and was refractory to conventional and omalizumab therapies although he had elevated IgE levels and eosinophilia. Our case supports the knowledge about the effectiveness and safety of rituximab not only in pemphigus but also in BP. On the other hand, although it did not work in our case, omalizumab may be a potentially effective agent in some carefully selected patients with certain subtypes of BP.

IgE-Related Chronic Diseases and Anti-IgE-Based Treatments

IgE is an immunoglobulin that plays a central role in acute allergic reactions and chronic inflammatory allergic diseases. The development of a drug able to neutralize this antibody represents a breakthrough in the treatment of inflammatory pathologies with a probable allergic basis. This review focuses on IgE-related chronic diseases, such as allergic asthma and chronic urticaria (CU), and on the role of the anti-IgE monoclonal antibody, omalizumab, in their treatment. We also assess the off-label use of omalizumab for other pathologies associated with IgE and report the latest findings concerning this drug and other new related drugs. To date, omalizumab has only been approved for severe allergic asthma and unresponsive chronic urticaria treatments. In allergic asthma, omalizumab has demonstrated its efficacy in reducing the dose of inhaled corticosteroids required by patients, decreasing the number of asthma exacerbations, and limiting the effect on airway remodeling. In CU, omalizumab treatment rapidly improves symptoms and in some cases achieves complete disease remission. In systemic mastocytosis, omalizumab also improves symptoms and its prophylactic use to prevent anaphylactic reactions has also been discussed. In other pathologies such as atopic dermatitis, food allergy, allergic rhinitis, nasal polyposis, and keratoconjunctivitis, omalizumab significantly improves clinical manifestations. Omalizumab acts in two ways: by sequestering free IgE and by accelerating the dissociation of the IgE-Fcε receptor I complex.

Dermatologic uses of omalizumabtitle

PURPOSE

Omalizumab is a recombinant humanized monoclonal antibody that inhibits the binding of immunoglobulin E (IgE) to the high-affinity IgE receptor (FceRI) on the surface of mast cells and basophils. Omalizumab has been approved for use in asthma, and new reports show promise in a variety of dermatologic diseases. Herein, we review the literature on omalizumab in dermatology and discuss the safety, efficacy and mechanisms of action for this emerging therapy.

MATERIALS AND METHODS

PubMED, MEDLINE and Embase databases were searched for the period 1 January 1990 to 1 September 2016. Articles sourced were graded according to the Oxford Center for Evidence-Based Medicine Levels of Evidence Grades of Recommendation criteria.

RESULTS

A total of 99 articles met our inclusion criteria. They included reports on the use of omalizumab in chronic spontaneous urticaria, atopic dermatitis, mastocytosis, hyper-IgE syndrome, bullous pemphigoid, Netherton syndrome, urticarial vasculitis, Churg-Strauss syndrome and toxic epidermal necrolysis.

CONCLUSIONS

Omalizumab is effective in a variety of recalcitrant immune-mediated and autoimmune skin disorders. It is a safe and effective treatment for use in chronic idiopathic urticaria (Grade of recommendation: A). Randomized clinical trials with long-term follow-ups are warranted to firmly establish the role of omalizumab in the treatment of dermatologic disease.

Off-Label Uses of Omalizumab

The off-label use of medicines is a common and extensive clinical practice. Omalizumab has been licensed for use in severe allergic asthma and chronic urticaria. Omalizumab dosing was based on body weight and baseline serum IgE concentration. All patients are required to have a baseline IgE between 30 and 700 IU/ml and body weight not more than 150 kg. The use of off-label drugs may lead to several problems including adverse effects and an increased risk/benefit balance. In this article, there are summarized off-label uses of omalizumab in the last recent years in diseases in which IgE maybe or certainly has a corner role such as allergic rhinitis, allergic bronchopulmonary aspergillosis, anaphylaxis, keratoconjunctivitis, food allergy, drug allergy, urticaria, angioedema, non-atopic asthma, atopic dermatitis, nasal polyps, Churg-Strauss syndrome, eosinophilic otitis media, chronic rhinosinusitis, bullous pemphigoid, contact dermatitis, and others. Use in pregnancy asthmatic women and pre-co-administration with specific immunotherapy will also be revised.

IgE-mediated mechanisms in bullous pemphigoid and other autoimmune bullous diseases

Autoimmune bullous diseases (AIBDs) are characterized by autoantibodies against structural proteins of the dermal-epidermal junction (in pemphigoid diseases) and the epidermal/ epithelial desmosomes (in pemphigus diseases). By far, the most common AIBD is bullous pemphigoid, which is immunopathologically characterized by autoantibodies against BP180 (type XVII collagen) and BP230. IgG and, to a lesser extent, IgA autoantibodies are the major autoantibody isotypes in these disorders. IgE autoantibodies are increasingly reported in particular in bullous pemphigoid. The development of specific and sensitive anti-BP180 IgE ELISA systems, the report of two experimental murine models employing IgE autoantibodies against BP180, and the successful treatment of bullous pemphigoid with the anti-IgE antibody omalizumab have raised interest in the role of IgE autoantibodies and the modulation of their production in AIBDs. Here, the relevance of IgE autoantibodies in the diagnosis, pathophysiology, and treatment decisions of AIBDs, with a focus on bullous pemphigoid, is reviewed.

T cell participation in autoreactivity to NC16a epitopes in bullous pemphigoid

Bullous pemphigoid is a blistering skin disease characterized by autoantibodies against the NC16a domain of bullous pemphigoid 180. This study was performed to characterize and map the fine specificity of T cell responses to NC16a. Peripheral blood mononuclear cells (PBMC) from a total of 28 bullous pemphigoid patients and 14 matched controls were tested for proliferative and cytokine responses to recombinant NC16a and a complete panel of 21 overlapping peptides spanning this region of BP180. Proliferative responses to NC16A and the peptide panel in the patients with active disease were similar in frequency and magnitude to those in healthy donors, and included late responses typical of naive cells in approximately 60% of each group. Interleukin (IL)-4 responses were slightly stronger for six peptides, and significantly stronger for Nc16a, in patients than in controls. Factor analysis identified factors that separate responses to the peptide panel discretely into IL-4, T helper type 2 (Th2) pattern, interferon (IFN)-γ, Th1 pattern and IL-10 or transforming growth factor [TGF-β, regulatory T cell (Treg )] pattern. Factors segregating IL-10 versus IFN-γ were predicted by active blistering or remission, and TGF-β or IL-10 versus IFN-γ by age. Finally, we confirmed a significant up-regulation of IgE responses to BP180 in the patients with pemphigoid. This shows the complexity of T cell phenotype and fine autoreactive specificity in responses to NC16A, in patients and in normal controls. Important disease-associated factors determine the balance of cytokine responses. Of these, specific IL-4 and IgE responses show the strongest associations with pemphigoid, pointing to an important contribution by Th2 cytokines to pathogenesis.

IgE autoantibodies in bullous pemphigoid: supporting role, or leading player?

Bullous pemphigoid (BP) is a common autoimmune blistering skin disease in which two hemidesmosomal components--the transmembrane collagen XVII (BP180 or BPAG2) and the plakin family protein BP230 (BPAG1)--are targeted by autoimmunity. Of these, collagen XVII (COL17) is thought to be a major autoantigen, and vital roles of IgG autoantibodies in blister formation have been elucidated. However, BP shows distinct features, including pruritic urticarial erythema and eosinophilic infiltration, which may be independent of IgG-mediated autoimmunity. Recently, it has been revealed that sera from certain patients with BP contain IgE autoantibodies to COL17 and that IgE autoantibodies bind to peri-lesional dermal-epidermal junctions. Mouse models have demonstrated that IgE antibodies to COL17 induce erythema and eosinophilic infiltration in skin. In addition, the successful treatment of severe BP with omalizumab, a humanized monoclonal antibody targeting IgE, has been reported. These findings suggest that both IgG and IgE autoantibodies to COL17 may be involved in the BP pathogenesis. This article summarizes IgE-mediated autoimmunity to COL17 in BP.

Bullous pemphigoid in infants: characteristics, diagnosis and treatment

BACKGROUND

Bullous pemphigoid (BP) in infants is a rare but increasingly reported autoimmune blistering skin disease. Autoantibody reactivity is usually poorly characterized. Current guidelines do not address specific aspects of the infantile form of BP. The objectives of this study are to define clinical and diagnostic characteristics of infantile BP and develop a treatment algorithm.

METHODS

Detailed characterization of a current case series of five infants with BP from our departments. Comprehensive analysis of all reported cases (1-12 months) with respect to clinical and laboratory characteristics, treatment and outcome.

RESULTS

In total 81 cases were identified (including our own). The mean age was 4.5 months. Moderately severe and severe disease was seen in 84% of cases. Involvement of hands and feet was present in all cases. Immunofluorescence microscopy was comparable with BP in adults. Where analyzed, the NC16A domain of bullous pemphigoid 180 kDa antigen/collagen XVII (BP180) was identified as the major target antigen. BP180 NC16A ELISA values in our cohort were significantly higher than in a control cohort of 28 newly diagnosed adult patients. 50% of patients were treated with systemic corticosteroids, 20% with a combination of systemic corticosteroids and dapsone or sulfapyridine and 10% with topical corticosteroids alone. 14% of patients needed a combination of multiple immunosuppressants. All but one patient reached remission. Relapses were rare.

CONCLUSIONS

Presentation of infantile BP is often severe with blistering of hands and feet present in all cases. Pathogenesis and diagnostic criteria are comparable to adult BP, yet BP180 NC16A ELISA levels seem to be significantly higher in infants. The overall disease outcome is favorable. Based on the results of this study we propose a treatment algorithm for infantile BP.

Human eosinophils express the high affinity IgE receptor, FcεRI, in bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease mediated by autoantibodies targeting BP180 (type XVII collagen). Patient sera and tissues typically have IgG and IgE autoantibodies and elevated eosinophil numbers. Although the pathogenicity of the IgE autoantibodies is established in BP, their contribution to the disease process is not well understood. Our aims were two-fold: 1) To establish the clinical relationships between total and BP180-specific IgE, eosinophilia and other markers of disease activity; and 2) To determine if eosinophils from BP patients express the high affinity IgE receptor, FcεRI, as a potential mechanism of action for IgE in BP. Our analysis of 48 untreated BP patients revealed a correlation between BP180 IgG and both BP180 IgE and peripheral eosinophil count. Additionally, we established a correlation between total IgE concentration and both BP180 IgE levels and eosinophil count. When only sera from patients (n = 16) with total IgE ≥ 400 IU/ml were analyzed, BP180 IgG levels correlated with disease severity, BP230 IgG, total circulating IgE and BP180 IgE. Finally, peripheral eosinophil count correlated more strongly with levels of BP180 IgE then with BP180 IgG. Next, eosinophil FcεRI expression was investigated in the blood and skin using several methods. Peripheral eosinophils from BP patients expressed mRNA for all three chains (α, β and γ) of the FcεRI. Surface expression of the FcεRIα was confirmed on both peripheral and tissue eosinophils from most BP patients by immunostaining. Furthermore, using a proximity ligation assay, interaction of the α- and β-chains of the FcεRI was observed in some biopsy specimens, suggesting tissue expression of the trimeric receptor form in some patients. These studies provide clinical support for the relevance of IgE in BP disease and provide one mechanism of action of these antibodies, via binding to the FcεRI on eosinophils.

Unraveling the significance of IgE autoantibodies in organ-specific autoimmunity: lessons learned from bullous pemphigoid

Bullous pemphigoid (BP), a cutaneous autoimmune blistering disease, has provided a useful model to elucidate a role for IgE in autoimmunity. IgE antibodies specific for the BP180 autoantigen are detected in sera and biopsy samples from the majority of BP patients. In BP biopsies, both IgE and BP180 antigen localize to the surface of mast cells, and incubation of circulating basophils from these patients with BP180 protein triggered degranulation. The in vivo pathogenicity of BP180-specific IgE was confirmed in mouse models, where injection of purified BP IgE into human skin grafted onto nu/nu mice replicated the early phase of lesion development, including mast cell degranulation, eosinophil infiltration and development of urticarial plaques. In addition, IgE antibodies from patient sera bind to BP180 on basal keratinocytes, resulting in internalization of BP180, production of inflammatory cytokines, IL-6 and IL-8, and a decrease in the number of hemidesmosomes at the basement membrane zone. These findings have led to therapeutic trials of the anti-IgE monoclonal antibody omalizumab in BP, resulting in substantial improvement in the patients' disease. Overall, the work in BP provides the first evidence for a pathogenic role for IgE in autoimmunity.