Subepidermal Blistering Disease Research Articles

Low pH condition impairs BP-IgG binding to the basement membrane zone.

Bullous pemphigoid (BP), an autoimmune subepidermal blistering disease, shows tense blisters associated with urticarial erythema. Tissue-bound Immunoglobulin G (IgG) at the basement membrane zone (BMZ) detected by direct immunofluorescence (DIF) is strong evidence for a diagnosis of BP. The sensitivity of DIF is higher in complement component 3 (C3) than in IgG, but the reason for this different sensitivity is not fully understood. In this study, we performed several exvivo studies to investigate the possible mechanism of IgG negativity and C3 positivity at the BMZ by DIF in some BP cases. First, sera from BP patients showing IgG negativity by DIF were found to clearly react to the BMZ in their own DIF skin samples. Next, indirect immunofluorescence (IIF) was performed using sera diluted with different pH phosphate-buffered saline (PBS), pH 7.4, 6.0, and 3.0. Patients' sera diluted with pH 7.4 PBS showed linear staining at the BMZ, but sera diluted with pH 6.0 PBS and pH 3.0 PBS showed lower fluorescence intensities. Finally, sections of skin from BP patients were pre-incubated with different pH PBS (pH 3.0, 6.0, and 7.4), followed by staining with anti-human IgG and C3. The fluorescence intensities were notably lower for IgG and C3 that had been pre-incubated with pH 3.0 PBS and pH 6.0 PBS than for IgG and C3 that had been pre-incubated with pH 7.4 PBS. These results suggest that a low pH condition hinders the binding of autoantibodies to the BMZ, that is, the drop in tissue pH induced by inflammation inhibits autoantibodies from depositing at the BMZ. Furthermore, the drop in tissue pH causes tissue-bound autoantibodies to detach from the BMZ. Complement fragments are activated not only on IgG but also on the cell surface of cells close to IgG during complement activation. IgG may detach from the BMZ under low pH condition induced by inflammation, but some complement fragments remain at the BMZ. These phenomena may help to explain why C3 is more sensitive than IgG when DIF is used to diagnose BP.

Anti-BP230 IgE autoantibodies in bullous pemphigoid intraindividually correlate with disease activity

BackgroundBullous pemphigoid (BP), the most common subepidermal autoimmune blistering disease, is classically defined by the presence of IgG autoantibodies directed against the hemidesmosomal proteins BP180 (type XVII collagen) and BP230 and the predominance of skin lesions. Several studies have addressed the role of anti-BP180 IgE in patients and experimental models, while data on anti-BP230 IgE are scarce. ObjectiveTo assess anti-BP230 IgE level by ELISA in BP sera and to correlate it with disease severity and clinical characteristics. MethodsBP sera underwent anti-BP230 IgE ELISA and Western blotting against human BP230 fragments. ResultsWe demonstrate that 36/154 (23%) of BP sera were positive for anti-BP230 IgE. Anti-BP230 IgE levels had no correlation with clinical phenotype or disease activity per se. Interestingly, anti-BP230 IgE was significantly associated with disease activity within individuals during the course of the disease. Additionally, anti-BP230 IgE and total IgE levels showed a significant correlation. Notably, anti-BP230 IgG correlated interindividually with disease activity. By Western blotting, the C-terminal domain of BP230 fragments (C2; amino acids 2024–2349 and C3; amino acids 2326–2649), provided the best serological assay for anti-BP230 IgE detection. ConclusionAs a complementary tool, IgE immunoblotting is recommended to obtain an optimal serological diagnosis, particularly in patients with severe disease without IgG reactivity by BP180- or BP230-specific ELISA. Although the detection of serum anti-BP230 IgE is not of major diagnostic significance, it may be relevant for therapeutic decisions, e.g., for anti-IgE-directed treatment, which has been successfully used in case series of BP.

Single-Cell Profiling Unveils the Inflammatory Heterogeneity within Cutaneous Lesions of Bullous Pemphigoid

Bullous pemphigoid (BP) is a subepidermal blistering skin disease with a complex pathogenesis involving various immune cells. However, the transcriptional features of these cells remain poorly defined. In this study, we constructed a comprehensive and single-cell resolution atlas of various immune cells within BP skin lesions through integrative single-cell analysis, flow cytometry, and multiplex immunohistochemistry. We observed prominent expansion and transcriptional changes in mast cells, macrophages, basophils, and neutrophils within BP lesions. Mast cells within the lesions adopted an active state and exhibited an elevated capacity for producing proinflammatory mediators. We observed an imbalance of macrophages/dendritic cells within BP lesions. Two macrophage subpopulations (NLRP3+ and C1q+) with distinct transcriptional profiles were identified and upregulated effector programs. T-peripheral helper-like T helper 2 cells were expanded in skin lesions and peripheral blood of patients with BP and were capable of promoting B-cell responses. In addition, we observed clonally expanded granzyme B-positive CD8+ T cells within BP lesions. Chemokine receptor mapping revealed the potential roles of macrophages and mast cells in recruiting pathogenic immune cells and underlying mechanisms within BP lesions. Thus, this study reveals key immune pathogenic features of BP lesions, thereby providing valuable insights for potential therapeutic interventions in this disease.

Linear IgA Bullous Dermatosis in Korea Using the Nationwide Health Insurance Database.

(1) Background: Linear immunoglobulin A bullous dermatosis (LABD) is a rare autoimmune, subepidermal blistering disease, characterized by linear IgA deposits along the epidermal basement membrane. LABD is idiopathic and is associated with medication and systemic autoimmune diseases. (2) Methods: We investigated the demographic characteristics, disease course, causative agents, and associated diseases in Korean patients with LABD. The Korean Health Insurance Review and Assessment Service database was used to obtain data. We identified 670 LABD cases between 2010 and 2022. (3) Results: The annual incidence of LABD was 1.3 per 100,000 persons, with a higher prevalence in individuals ≥60 years old. The patients were treated with dapsone for 30.7 ± 56.7 days, had 1.3 ± 0.7 hospital visits, and were hospitalized for 19.8 ± 19.7 days. Risk factors, including malignancy, commonly preceded LABD. Antibiotic use, specifically vancomycin and third-generation cephalosporins, was a risk factor. The mean age of LABD diagnosis was 55.9 ± 21.7 years. (4) Conclusion: This is the first published study to assess a nationwide cohort for LABD. The incidence of LABD was higher than that in other studies. Most case reports have linked LABD with the administration of specific antibiotics; however, this study shows there were more associations with other conditions.

Subepidermal blistering disease presenting with anti-p200 and anti-type VII collagen autoantibodies.

Subepidermal blistering disease presenting with anti-p200 and anti-type VII collagen autoantibodies.

Bullous pemphigoid and diabetes mellitus: a systematic review and meta-analysis.

We aimed to systematically review and meta-analyze the association between diabetes mellitus (DM) and bullous pemphigoid (BP). Bullous pemphigoid (BP) is a prevalent autoimmune subepidermal blistering disease. Comorbid health conditions like neurological diseases and malignancies have been associated with BP. Growing evidence suggests that type 2 diabetes mellitus (T2DM) may increase the risk of developing BP. This review aims to synthesize this evidence. A systematic literature review was performed using Medline, PubMed, and Scopus in March 2022. Studies exploring the association between BP and DM were included. Data were extracted, and quality was assessed using the Newcastle-Ottawa scale. Meta-analysis was conducted to identify the odds ratio (OR) and 95% confidence intervals (CI) of the association. Seventeen studies were included, most being case-control studies from Europe and Asia. The pooled OR was 2.06 (95% CI: 1.61-2.62), suggesting a significant association between DM and BP. However, strong heterogeneity (I2 = 88%) was observed. Evidence consolidates a significant relationship between DM and BP, potentially due to alterations in the immune system and skin properties caused by diabetes. Strengths of this review include a comprehensive search, rigorous methodology, large sample size, and heterogeneity evaluation. However, varying study quality, potential publication bias, and unaccounted confounding factors present limitations. There is a potential link between T2DM and an increased risk of BP. Further studies are required to understand this association and the underlying mechanisms.

Laminin β4 is a constituent of the cutaneous basement membrane zone and additional autoantigen of anti-p200 pemphigoid

Anti-p200 pemphigoid is a subepidermal autoimmune blistering disease (AIBD) characterized by autoantibodies against a 200kDa protein. Laminin γ1 has been described as target antigen in 70% to 90% of patients. No diagnostic assay is widely available for anti-p200 pemphigoid, which might be due to the unclear pathogenic relevance of anti-laminin γ1 autoantibodies. To identify a target antigen with higher clinical and diagnostic relevance. Immunoprecipitation, mass spectrometry, and immunoblotting were employed for analysis of skin extracts and sera of patients with anti-p200 pemphigoid (n=60), other AIBD (n=33), and healthy blood donors (n=29). To localize the new antigen in skin, cultured keratinocytes and fibroblasts, quantitative real-time polymerase chain reaction and immunofluorescence microscopy were performed. Laminin β4 was identified as target antigen of anti-p200 pemphigoid in all analyzed patients. It was located at the level of the basement membrane zone of the skin with predominant expression in keratinocytes. A higher number of sera needs to be tested to verify that laminin β4 is the diagnostically relevant antigen of anti-p200 pemphigoid. The identification of laminin β4 as an additional target antigen in anti-p200 pemphigoid will allow its differentiation from other AIBD and as such, improve the management of these rare disorders.

P18 Epidermolysis bullosa acquisita in children: report of three cases

Abstract Epidermolysis bullosa acquisita (EBA) is an acquired, subepidermal blistering skin disease characterized by autoantibodies against type VII collagen, which links the epidermis to the dermis at the dermo-epidermal junction. Clinically, patients have skin fragility and blisters over trauma-prone sites, scarring, milia and onychodystrophy. The diagnosis can be challenging as it shares clinical and histopathological features with other immunobullous diseases. Although exceptionally rare in children, we report three paediatric patients with EBA and variable disease severity. The main clinical features were blisters (n = 3), milia (n = 3), scarring (n = 2), oral erosions (n = 2) and onychodystrophy (n = 1). Histological findings were nonspecific, showing a subepidermal blister with various inflammatory infiltrates. On direct immunofluorescence a bright deposit of IgG was seen, and the antibodies adhered to the dermal side of the salt-split in two cases. ELISA analysis confirmed circulating autoantibodies against type VII collagen in one patient. All received a course of oral corticosteroids alongside steroid-sparing agents such as dapsone, azathioprine and rituximab depending on clinical response and shared favourable prognosis. Early use of topical steroids can help but high-dose oral corticosteroids are often required as well as steroid-sparing agents such as dapsone, methotrexate, azathioprine, ciclosporin, mycophenolate mofetil, cyclophosphamide and rituximab. In our experience, although the treatment approaches have been different, all the patients had favourable outcomes.

Accuracy of serration pattern analysis by direct immunofluorescence in subepidermal autoimmune blistering diseases.

Background Direct immunofluorescence (DIF) is essential for the diagnosis of sub-epidermal immunobullous diseases (SIBD). Bullous pemphigoid (BP), a sub-epidermal immunobullous disease, shows linear IgG and C3 deposition along the dermo-epidermal junction by DIF. However, similar histological and DIF findings are also seen in epidermolysis bullosa acquisita (EBA). High-power examination of antibody deposition by DIF in a "u" or "n" serrated pattern can help differentiate these two entities. Aims/Objectives The aim of this study was to determine the diagnostic accuracy of serration patterns in IgG-mediated sub-epidermal immunobullous disease. Methods All cases of IgG-mediated sub-epidermal immunobullous disease diagnosed over the past 2 years and 9 months period and confirmed serologically, were included. Examination of the serration pattern in DIF was assessed on oil emersion. Salt split skin indirect immunofluorescence (SSS IIF), BP180 enzyme-linked immunosorbent assay (ELISA), profile ELISA and BIOCHIP mosaic were performed, wherever available. Results This study included 74 cases of bullous pemphigoid, eight cases of mucus membrane pemphigoid (MMP) and one case of epidermolysis bullosa acquisita. The characteristic zigzag "n" pattern was visualised in 66 out of 82 cases (80.5%) of the pemphigoid group (BP + MMP); the single epidermolysis bullosa acquisita case showed the "u" serrated pattern. No statistical correlation was seen between serration pattern and BP180 positivity by ELISA (P = 0.05). Limitations The study is limited by the single case of epidermolysis bullosa acquisita (which could be due to rarity of this disease in north Indian population due to genetic variation), lack of detailed serological investigations and immunoblot in all cases. Conclusion Serration pattern analysis is an easy-to-interpret and highly useful technique for characterisation of sub-epidermal immunobullous diseases.

Dietary habits in Japanese patients with bullous pemphigoid: low intake of retinol.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease. Dietary habits may modulate the pathogenesis of BP. We evaluated dietary habits in Japanese patients with BP and compared their results to those of age- and sex-matched healthy controls. We also examined the relationship between dietary habits versus IgG anti-BP180NC16A antibody or parameters of BP disease area index (BPDAI); cutaneous blisters/erosions, cutaneous urticaria/erythema, and mucosal blisters/erosions. Dietary habits were assessed by the validated, Brief-type self-administered Diet History Questionnaire. Severity of disease was assessed with BPDAI. Patients with BP showed a lower intake of retinol (vitamin A1) and beverages, and a higher intake of seasoning/spices, compared to controls. The bivariate and multivariable logistic regression analysis showed that BP was associated with a low intake of retinol and beverages. There were no significant correlations between IgG anti-BP180NC16A antibody levels and intake of nutrients/foods. The BPDAI score for cutaneous blisters/erosions significantly positively correlated with intake of carbohydrate and negatively with intake of retinol, vitamin A, animal fat, cholesterol, phosphorus, and vitamin B2. The BPDAI score for cutaneous urticaria/erythema significantly negatively correlated with intake of vitamin A. BP patients with mucosal blisters/erosions had a higher intake of cholesterol, n-6 polyunsaturated fatty acid, and eggs, and lower intake of seasoning/spices, compared to patients without BP. The supplementation of vitamin A might have prophylactic and/or therapeutic effects on BP.

Anti-NC16A IgA from Patients with Linear IgA Bullous Dermatosis Induce Neutrophil-Dependent Subepidermal Blistering in Mice

Linear IgA bullous dermatosis (LABD) is an acquired autoimmune subepidermal blistering skin disease characterized by circulating and tissue-bound IgA autoantibodies that recognize epitopes within the hemidesmosomal protein BP180, including its NC16A domain. Histologically, LABD has long been defined by neutrophil infiltration and dermal-epidermal separation. However, the pathogenic roles of anti-NC16A IgA and neutrophils in LABD, as well as their interactions, have not been thoroughly studied. We show that passive transfer of patient-derived anti-NC16A IgA induce clinical and histologic LABD pathology in humanized NC16A mice that are reconstituted locally or systemically with human neutrophils. The lesional skin of mice exhibits significantly elevated levels of the neutrophil chemoattractants CXCL-1 and CXCL-2. Furthermore, we show significantly increased levels of the neutrophil chemoattractant IL-8 in blister fluids of patients with LABD. This study provides direct evidence that anti-NC16A IgA in patients with LABD are pathogenic and interact with neutrophils to mediate tissue injury and subepidermal blister formation. This study further corroborates the importance of neutrophil-mediated tissue injury in LABD disease physiology and establishes a clinically relevant invivo model system that can be used to systematically dissect the immunopathogenesis of LABD.

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

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

Atypical subepidermal blistering disease following COVID‐19 vaccination

Atypical bullous disease after COVID‐19 vaccination.

Localized Bullous Pemphigoid

A man in his 80s presented with a pruritic, focally ulcerated pink plaque with overlying blisters on the left lateral thigh (Figures 1 and 2). This had been the site of an excision 9 months earlier. Over time, pruritic vesicles and bullae developed at the surgical site. Punch biopsies showed a subepidermal bulla with extensive eosinophilic infiltrate on histopathology and linear deposition of C3 and immunoglobulin G (IgG) at the basement membrane zone on direct immunofluorescence, confirming the diagnosis of localized bullous pemphigoid (BP).Figure 2Close-up view of vesicles and bullae at the periphery.View Large Image Figure ViewerDownload Hi-res image Download (PPT) BP is a subepidermal autoimmune blistering disease caused by autoantibodies to hemidesmosome proteins BP180 (BP antigen 2) or BP230 (BP antigen 1). Classically, patients present with pruritic urticarial papules and plaques and tense vesicles and bullae. Diagnosis is made by examination of the tissue and direct immunofluorescence, which show a subepidermal accumulation of eosinophils and linear deposition of IgG and/or C3 in an n-serrated pattern along the basement membrane zone, respectively. Enzyme-linked immunosorbent assay (ELISA) for autoantibodies to the NC16a domain of BP180 and to BP230 is supportive, and anti-BP180-NC16a ELISA may aid in monitoring disease activity during treatment.1Schmidt E. Zillikens D. Pemphigoid diseases.Lancet. 2013; 381: 320-332https://doi.org/10.1016/S0140-6736(12)61140-4Abstract Full Text Full Text PDF PubMed Scopus (705) Google Scholar,2Feliciani C. Joly P. Jonkman M.F. et al.Management of bullous pemphigoid: the European Dermatology Forum consensus in collaboration with the European Academy of Dermatology and Venereology.Br J Dermatol. 2015; 172: 867-877https://doi.org/10.1111/bjd.13717Crossref PubMed Scopus (233) Google Scholar Most cases of BP are generalized. Rarely, it is localized, usually to sites of previous skin injury, surgery, radiation, or venous insufficiency.3Ständer S. Kasperkiewicz M. Thaçi D. et al.Prevalence and presumptive triggers of localized bullous pemphigoid.J Dermatol. 2021; 48: 1257-1261https://doi.org/10.1111/1346-8138.15912Crossref PubMed Scopus (4) Google Scholar Although the pathophysiology of localized BP is not well understood,4Danescu S. Chiorean R. Macovei V. Sitaru C. Baican A. Role of physical factors in the pathogenesis of bullous pemphigoid: case report series and a comprehensive review of the published work.J Dermatol. 2016; 43: 134-140https://doi.org/10.1111/1346-8138.13031Crossref PubMed Scopus (39) Google Scholar topical steroids are first-line therapy and are generally effective.2Feliciani C. Joly P. Jonkman M.F. et al.Management of bullous pemphigoid: the European Dermatology Forum consensus in collaboration with the European Academy of Dermatology and Venereology.Br J Dermatol. 2015; 172: 867-877https://doi.org/10.1111/bjd.13717Crossref PubMed Scopus (233) Google Scholar Our patient was treated with topical clobetasol 0.05% ointment twice daily for 3 weeks with excellent results, and subsequent use as needed to maintain clearance. The authors report no competing interests.

Erosive and ulcerative stomatitis in dogs and cats: which immune-mediated diseases to consider?

Immune-mediated and autoimmune diseases of the skin often present with oral cavity involvement. Autoimmune subepidermal blistering diseases and pemphigus vulgaris are classic examples. While the primary lesions (vesicles and bullae) are relatively specific, these fragile lesions evolve rapidly into erosions and ulcers, which are lesion types that overlap with many diseases. Furthermore, some immune-mediated diseases such as severe adverse drug reactions, lupus diseases, canine uveodermatological syndrome, and vasculitis, may or may not involve the oral cavity, and often nonoral clinical manifestations are more diagnostic. In these situations, disease knowledge combined with signalment, lesion distribution, and history help to narrow the differentials. Surgical biopsy is required for confirmation in most diseases, while immunosuppressive treatments most typically involve glucocorticoids with or without nonsteroidal immunosuppressants.

Nail abnormalities in subepidermal blistering diseases: a cross-sectional study.

Nail involvement in subepidermal autoimmune blistering diseases (SEABD) is not common. Although these changes can be transient, permanent changes can also occur. This study addresses nail involvement manifestations and their associated factors in patients with SEABD. From March 2020 to March 2021, we enrolled 56 patients with SEABD who were being examined at a tertiary skin hospital and checked their nail changes. We investigated the association between the SEABD subtypes and treatments that patients were receiving and the nail abnormalities. Additional factors including age, gender, duration since diagnosis, presence of mucosal involvement, and anti-bp230 and anti-bp180 IgG antibody quantitative levels (in those patients with bullous pemphigoid) were analyzed. The most common nail abnormalities were ridging, onycholysis, and onychoschizia. We observed a lower prevalence of onycholysis in EBA, a lower prevalence of periungual bullae in MMP, and a higher prevalence of scarring loss in EBA. Rituximab and dapsone were effective in preventing onycholysis as well as prednisolone in preventing subungual hematoma. Multiple lesions were found to be more common in the foot digits including great toes, probably because of higher exposure to trauma. In summary, in patients with SEABD and concomitant nail involvement, the underlying disease control, proper treatment, and avoidance of trauma may be helpful.

Nail Changes in Immuno-Bullous Disorders: A Cross-Sectional Study.

Autoimmune blistering (AIBD) disorders affect mucosae, skin, and appendages. Appendageal involvement has not been studied extensively to date. However, they are important as nail changes are commonly encountered during a flare-up of the disease. To determine the prevalence and patterns of nail changes in various Immunobullous disorders and to study the relationship between the nail changes and the disease duration and severity. A cross-sectional study was conducted at the Department of Dermatology, venerology, and leprosy at a tertiary care center in Mumbai. A cross-sectional study including a total of 74 cases of Immunobullous diseases was conducted and the prevalence of nail changes was determined. The association between the mean number of nail changes and the disease duration and severity was analyzed using ANOVA (Analysis of variance) and unpaired t-test. The Statistical Package for Social Studies (SPSS) software was used for statistical evaluation. We found that the prevalence of nail changes was 91%. There was a significant difference in the mean number of nail changes with respect to the severity grades of mucosal involvement in AIBD (P value < 0.05). There was no significant difference in the mean number of nail changes with respect to the severity grades of Pemphigus vulgaris (PV), Pemphigus foliaceous (PF), subepidermal blistering diseases, and the duration of AIBD. Nails are frequently affected in AIBD. The number of nail changes is related to the severity of mucosal disease but not to duration.

Epidermolysis Bullosa Acquisita-Current and Emerging Treatments.

Epidermolysis bullosa acquisita (EBA) is a rare chronic autoimmune subepidermal blistering disease of the skin and mucous membranes, usually beginning in adulthood. EBA is induced by autoantibodies to type VII collagen, a major component of anchoring fibrils in the dermal-epidermal junction (DEJ). The binding of autoantibodies to type-VII collagen subsequently leads to the detachment of the epidermis and the formation of mucocutaneous blisters. EBA has two major clinical subtypes: the mechanobullous and inflammatory variants. The classic mechanobullous variant presentation consists of skin fragility, bullae with minimal clinical or histological inflammation, erosions in acral distribution that heal with scarring, and milia formation. The inflammatory variant is challenging to differentiate from other autoimmune bullous diseases, most commonly bullous pemphigoid (BP) but also mucous membrane pemphigoid (MMP), Brunsting-Perry pemphigoid, and linear IgA dermatosis. Due to its recalcitrance conventional treatment of epidermolysis bullosa acquisita is shown to be demanding. Here we discuss novel therapeutic strategies that have emerged and which could potentially improve the quality of life in patients with EBA.

The efficacy of adding oral sodium cromoglycate to stable treatment for controlling bullous pemphigoid-related pruritus: A retrospective study.

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease which mainly affects the elderly. It manifests as severe pruritus, urticarial plaques, and tense bullae and is associated with significant mortality. Therapy options for itch in BP patients are limited, mainly because the pathogenesis of itch in BP remains unclear. Sodium cromoglycate was commonly used in the past as an inhaled drug for the management of bronchial asthma and as an oral treatment for children with urticaria pigmentosa. In this study we sought to assess its efficacy in reducing BP associated itch. Assessing the efficacy of oral sodium cromoglycate in reducing BP-related pruritus after stabilization of disease activity. We retrospectively reviewed the medical records of patients with a confirmed diagnosis of BP who were treated with sodium cromoglycate. Patient reported outcome measures (PROM) including: BPDAI pruritus, ABQOL and TABQOL, and BPDAI activity score were compared at two points in time: before commencing treatment with sodium cromoglycate or before commencing maximal dose of this treatment, and at least 4 weeks after treatment commencement. A total of 21 patients met the inclusion criteria. After at least 4 weeks of treatment with oral sodium cromoglycate BPDAI pruritus, ABQOL and TABQOL scores were statistically significantly decreased compared to the scores prior to treatment commencement, P < 0.000, P < 0.008, and P < 0.004, respectively. Oral treatment with sodium cromoglycate for the management of pruritus in BP patients may be beneficial, however, further prospective studies are required to better assess its efficacy.

What's new in the pathogeneses and triggering factors of bullous pemphigoid.

Bullous pemphigoid (BP) is a subepidermal blistering disease induced by autoantibodies to type XVII collagen (COL17, also called BP180) and BP230. Previous studies using patients' samples and animal disease models elucidated the complement-dependent and complement-independent pathways of blister formation, the pathogenic roles of immune cells (T and B cells, macrophages, mast cells, neutrophils, eosinophils), and the pathogenicity of IgE autoantibodies in BP. This review introduces the recent progress on the mechanism behind the epitope-spreading phenomenon in BP, which is considered to be important to understand the chronic and intractable disease course of BP, and the pathogenicity of anti-BP230 autoantibodies, mainly focusing on studies that used active disease models. To clarify the pathogenesis of BP, the mechanism behind the breakdown of immune tolerance to BP antigens should be investigated. Recent studies using various experimental models have revealed important roles for regulatory T cells in the maintenance of self-tolerance to COL17 and BP230 as well as in the suppression of inflammation triggered by the binding of antibodies to COL17. Notably, physical stresses such as trauma, thermal burns, bone fractures, irradiation and ultraviolet exposure, some pathologic conditions such as neurological diseases and hematological malignancies, and the use of dipeptidyl peptidase-IV inhibitors and immune checkpoint inhibitors have been reported as triggering factors for BP. These factors and certain underlying conditions such as genetic background, regulatory T-cell dysfunction or aging might synergistically affect some individuals and eventually induce BP. Further studies on the breakdown of self-tolerance and on the identification of key molecules that are relevant to blister formation and inflammation may expand our understanding of BP's etiology and may lead to the development of novel therapeutic approaches.