Bullous pemphigoid-What do we know about the most recent therapies?

Isolation and analysis of the exosomal membrane proteins in bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is a severe autoimmune sub-epidermal bullous disease. Exosomes are small extracellular vesicles secreted by most cell types. The exosomal membrane proteins are implicated in various biological and pathological pathways. This study aims to explore the potential roles of exosomes in BP pathomechanism.

RESEARCH DESIGN

We collected plasma samples from 30 BP patients and 31 healthy controls. Nanoparticle tracking analysis (NTA) was used to analyze the size and concentration of exosomes. The immunogold labelling experiment and extracellular vesicle (EV) array were performed to detect the content and distribution of exosomes.

RESULTS

The exosomes from both the BP and control groups' plasma were successfully extracted. EV Array showed that CD63 and CD9 levels were significantly higher in the BP group than in the control group (p < 0.05). Expression levels of the BP180 NC16A and intracellular domain (ICD) were higher in the anti-BP180 positive group versus the controls (p < 0.05). The active BP group exhibits higher CD63 and BP180 ICD protein concentrations than the control or inactive BP groups (p < 0.05).

CONCLUSION

BP180 autoantigen fragments were expressed on the exosomal membrane in BP patients. The BP180 ICD and CD63 on exosomes could potentially be novel biomarkers for monitoring disease activity.

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.

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.

Analysis of the clinical characteristics of pembrolizumab-induced bullous pemphigoid

Background

Pembrolizumab, a programmed cell death protein 1 checkpoint inhibitor, is a novel drug used to treat a variety of advanced malignancies. However, it can also result in many immune-related adverse events, with cutaneous toxicities being the most frequent. Regarding pembrolizumab-induced skin adverse reactions, bullous pemphigoid (BP) has the worst effects on quality of life. Recently, there have been more and more reports of BP incidents resulting from pembrolizumab therapy in patients with cancer. This study aimed to define the clinical characteristics, diagnosis and management of pembrolizumab-induced BP and identify potential differences between classical BP and pembrolizumab-induced BP.

Methods

Case reports, case series, and case analyses of pembrolizumab-induced BP up to 10 December 2022 were collected for retrospective analysis.

Results

Our study included 47 patients (33 males and 14 females) from 40 studies. The median age was 72 years (range 42-86 years). The median time to cutaneous toxicity was 4 months (range 0.7-28 months), and the median time to bullae formation was 7.35 months (range 0.7-32 months). The most common clinical features were tense bullae and blisters (85.11%), pruritus (72.34%), and erythema (63.83%) on the limbs and trunk. In 20 of the 22 cases tested, the serum anti-BP180 autoantibodies were positive. However, in 10 cases (91.90%, 10/11) the circulating autoantibodies of anti-BP230 were negative. 40 patients had skin biopsies and the skin biopsy revealed subepidermal bullae or blister eosinophil infiltration in 75.00% of patients with pembrolizumab-induced BP, 10.00% of patients with lymphocyte infiltration and 20.00% of patients with neutrophil infiltration. There were 20 patients (50%) with eosinophilic infiltration around the superficial dermis vessels, 8 patients (20.00%) with lymphocyte infiltration around the superficial dermis vessels, and 4 patients (10.00%) with neutrophil infiltration around the superficial dermis vessels. Direct immunofluorescence detected linear immunoglobulin G (IgG) IgG and/or complement C3 along the dermo-epidermal junction in 36 patients (94.74%) with BP. IgG positivity was detected by indirect immunofluorescence in 81.82% of patients with BP. All patients were in complete remission (95.65%,44/46) or partial remission (4.35%, 2/46) of BP, whereas 9/46 patients had a relapse or refractory. The majority of patients achieved BP remission after discontinuation of pembrolizumab with a combination of topically and systemically administered steroid treatments, or other medications. The median duration of BP remission was 2 months (range 0.3-15 months).

Conclusion

A thorough diagnosis of pembrolizumab-induced BP should be made using clinical signs, biochemical markers, histopathological and immunopathological tests. Pembrolizumab-induced BP had similar clinical characteristics to classic BP. Temporary or permanent discontinuation of pembrolizumab therapy may be required in patients with perbolizumab-induced BP depending on the severity of BP and the response to medication. Pembrolizumab-induced BP may be effectively treated using topical and systemic steroid treatments in combination with other medications (e.g., doxycycline, niacinamide, dapsone, rituximab, intravenous immunoglobulins, dupilumab, cyclophosphamide, methotrexate, mycophenolate mofetil, and infliximab). Clinicians should provide better management to patients with BP receiving pembrolizumab to prevent progression and ensure continuous cancer treatment.