Usefulness of Enzyme-linked Immunosorbent Assay Using Recombinant BP180 and BP230 for Serodiagnosis and Monitoring Disease Activity of Bullous Pemphigoid

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

BACKGROUND

Bullous 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.

OBJECTIVE

To assess anti-BP230 IgE level by ELISA in BP sera and to correlate it with disease severity and clinical characteristics.

METHODS

BP sera underwent anti-BP230 IgE ELISA and Western blotting against human BP230 fragments.

RESULTS

We 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.

CONCLUSION

As 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.

Skin-Related Quality of Life During Autoimmune Bullous Disease Course

Importance

Autoimmune bullous diseases (AIBDs) are chronic relapsing-remitting conditions with significant morbidity. Skin-related quality of life (SRQL) may vary by AIBD subtype and disease type. Disease severity and flare severity can be difficult to define; SRQL can offer a key insight.

Objectives

To investigate the Skindex-16 score as an SRQL measure in AIBD subtypes during flare and nonflare states and to evaluate Skindex-16 construct validity.

Design, Setting, and Participants

This retrospective cross-sectional study was conducted from September 1, 2016, to February 1, 2020, among 192 patients at the University of Utah Health autoimmune dermatology clinic with pemphigoid, pemphigus, dermatitis herpetiformis, and linear immunoglobulin A disease. Patients had an encounter-associated diagnosis, Skindex-16 scores, and self-reported flare status. Statistical analysis was performed from March 2022 to June 2023.

Exposure

Autoimmune bullous disease subtype and patient-reported flare status.

Main Outcomes and Measures

Skindex-16 domain scores (emotions, symptoms, and functioning; range, 0-100, where 0 indicates no effect on SRQL and 100 maximum effect) and individual item scores were described by disease and flare status. Flare scores were expected to be higher by at least the standard error of measurement (SEm). Convergent validity was assessed using Spearman correlation among Skindex-16 scores, serologic titers, and other patient-reported outcome measures. Floor or ceiling domain scores (<20% of sample scoring either lowest or highest possible domain scores, respectively) were assessed for Skindex-16. Structural validity was assessed using confirmatory factor analysis (CFA).

Results

The study included 192 patients with 212 visits (median age, 68 years [IQR, 58-76 years]; 123 of 212 women [58.0%]) with Skindex-16 scores (64 in flare state and 148 in nonflare state). Median Skindex-16 domain scores were higher for all disease categories among patients in the flare state compared with those in the nonflare state (pemphigoid [emotions: flare, 52.4 (IQR, 38.1-69.0); nonflare, 7 (IQR, 0-17); symptoms: flare, 37.5 (IQR, 29.2-58.0); nonflare, 13 (IQR, 0-25); functioning: flare, 26.7 (IQR, 10.0-56.7); nonflare, 0 (IQR, 0-3)]; pemphigus [emotions: flare, 54.8 (IQR, 31.0-81.0; nonflare, 0 (IQR, 0-19); symptoms: flare, 58.3 (IQR, 41.7-70.8); nonflare, 4 (IQR, 0-12.5); functioning: flare, 26.7 (IQR, 13.3-83.3); nonflare, 0 (IQR, 0-3.33)]; dermatitis herpetiformis [emotions: flare, 72.6 (IQR, 34.7-90.5); nonflare, 14.3 (IQR, 2.4-26.2); symptoms: flare, 69 (IQR, 31.3-85.4); nonflare, 12.5 (IQR, 0-29.2); functioning: flare, 38.3 (IQR, 5.0-63.2); nonflare, 0 (IQR, 0-13.3)]. This difference exceeded SEm cut points. Cronbach α was greater than 0.80 for all domains and AIBDs. Moderate or low correlations were seen with desmoglein 1 and bullous pemphigoid 180 titers. Moderate correlation existed between Skindex-16 and Patient-Reported Outcomes Measurement Information System Depression scores (emotions: ρ = 0.40; symptoms: ρ = 0.41; functioning: ρ = 0.48), and strong correlation existed between Skindex-16 and patient-reported disease severity (emotions: ρ = 0.71; symptoms: ρ = 0.73; functioning: ρ = 0.66). Floor domain scores greater than 20% were seen among patients in the nonflare state, but ceiling domain scores were rare (<10% for all domains); CFA model fit was poor.

Conclusions and Relevance

In this cross-sectional study, SRQL was highly associated with flare of AIBDs. Skin-related quality of life was worse during periods without flare among patients with pemphigoid and dermatitis herpetiformis compared with pemphigus, highlighting residual SRQL morbidity. Skindex-16 showed good construct validity, but the poor CFA model fit needs further research. Clinical measurement of SRQL in AIBDs can add critical disease-severity information.

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio are positively correlated with disease activity of bullous pemphigoid

Bullous pemphigoid (BP) is a complex inflammatory process with elevated levels of autoantibodies, eosinophils, neutrophils, and various cytokines. Hematological inflammatory biomarkers can reflect inflammatory state in various diseases. Up to now, the correlations of hematological inflammatory biomarkers and disease activity of BP remain unknown. The purpose of this study was to clarify the associations between hematological inflammatory biomarkers and disease activity of BP. The levels of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet-to-neutrophil ratio (PNR) and mean platelet volume (MPV) of 36 untreated BP patients and 45 age and gender matched healthy controls were detected by routine blood tests. The correlations between hematological inflammatory markers and clinical characteristics of BP were statistically analyzed. The Bullous Pemphigoid Disease Area Index (BPDAI) was used to measure disease activity of BP. The mean levels of NLR, PLR, PNR and MPV in 36 untreated BP patients were 3.9, 157.9, 45.7 and 9.4 fl, respectively. Increased NLR (p < 0.001), PLR (p < 0.01), and MPV (p < 0.001) but decreased PNR (p < 0.001) were observed in BP patients when compared with healthy controls. In BP patients, the levels of NLR were positively correlated to BPDAI Erosion/Blister Scores (p < 0.01); and the levels of NLR and PLR were both positively correlated to BPDAI without Damage Score (both p < 0.05) and BPDAI Total Score (both p < 0.05). No correlation was found in other statistical analyses between hematological inflammatory markers and clinical characteristics in BP patients involved in the present study. Therefore, NLR and PLR are positively correlated with disease activity of BP.

Utility of the pattern-based approach using BIOCHIP-indirect immunofluorescence in the evaluation of subepidermal bullous disorders

BACKGROUND

Subepidermal bullous disorders (SEBD) are a heterogeneous group of vesiculobullous diseases because of antibody-mediated destruction of proteins of the dermo-epidermal junction. Direct immunofluorescence (DIF) is the gold standard for diagnosis. BIOCHIP-indirect immunofluorescence (IIF) is a novel serological test that combines multiple target antigens in a single field. The present study aimed to evaluate the utility of the pattern-based approach in BIOCHIP-IIF for the diagnosis of SEBD.

METHODS

Seventy cases of BIOCHIP-IIF that showed clinical, histopathological, and/or DIF features favoring SEBD were included in the study. The interpretation in the BIOCHIP was categorized into one of the following patterns. Pattern I: basement membrane zone (BMZ) staining in monkey esophagus (ME), primate salt-split skin (SSS)-roof staining, BP180+ and/or BP230+; Pattern II: roof staining in SSS, BP180- and BP230- with or without BMZ staining in ME; Pattern III: floor staining in SSS, BP180- and BP230-; and pattern IV: negative in SSS and other substrates. The findings were correlated with histopathology and/or DIF.

RESULTS

Fifty (71.5%) cases showed pattern I or the typical bullous pemphigoid (BP) pattern. Eight (11.4%) cases showed pattern II. Patterns III and IV were observed in seven (10%) and five (7.1%) cases, respectively. BP was the most common diagnosis in patterns I and II, while anti-p200 pemphigoid was most common in pattern III, as confirmed by immunoblotting. The sensitivity of pattern I in the diagnosis of BP was 96%.

CONCLUSION

BIOCHIP-IIF showed a good correlation with DIF and histopathology in the diagnosis of SEBD. This can be used as a first-line investigation in case of bullous disorders.

A Cross-Sectional Study to Correlate Disease Severity in Bullous Pemphigoid Patients with Serum Levels of Autoantibodies Against BP180 and BP230

Context:

Enzyme-linked immunosorbent assay (ELISA) for BP 180 and 230 antibodies is commonly done in patients with bullous pemphigoid. We could not find much data regarding the usefulness of this test to predict the disease severity in Indian population.

Aims:

We studied the correlation of IgG anti BP180 and anti BP230 antibody titer with disease severity and clinical features in bullous pemphigoid.

Settings and Design:

This cross-sectional study was conducted at a tertiary care center in western India.

Materials and Methods:

Forty-two clinically diagnosed treatment-naive cases of bullous pemphigoid were enrolled and investigated with skin punch biopsy, IgG anti BP180, and anti BP230 ELISA, direct immunofluorescence, and indirect immunofluorescence tests. Disease severity was assessed by calculating modified Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) score. Thirty patients with a final diagnosis of bullous pemphigoid were included in the statistical analysis. Pearson's correlation coefficient (r) was used to study correlation.

Results:

The mean ABSIS skin score was 32.81 when both tests were negative, 42.13 when only BP230 was positive, 76.28 when only BP180 was positive, and 78.16 when both were positive. Pearson's correlation coefficient (r) for BP180 and ABSIS skin score was 0.6 (P value: 0.0005), and for BP230 was -0.055 (P value: 0.600).

Conclusions:

BP antibody titers correlate partially with disease severity. Anti-BP180 antibody is associated with more severe disease. Anti-BP230 antibody titer does not correlate with disease severity.

Bacterial Skin Infections in Hospitalized Patients with Bullous Pemphigoid

OBJECTIVE

To explore the features and risk factors of bacterial skin infections (BSIs) in hospitalized patients with bullous pemphigoid (BP).

METHODS

Records were retrospectively reviewed for 110 hospitalized patients with BP admitted to Peking University First Hospital between 2013 and 2019. Bacterial species and drug resistance were assessed, and then the underlying risk factors for BSIs were evaluated.

RESULTS

Infections were present in 40% (44/110) of the patients. Staphylococcus aureus (72.7%, 32/44) was the most common bacterium, and it was highly resistant to penicillin (81.3%, 26/32), erythromycin (62.5%, 20/32), and clindamycin (56.3%, 18/32), but 100.0% sensitive to vancomycin and tigecycline. Coronary heart disease (P = .02; odds ratio [OR], 12.68), multisystem comorbidities (P = .02; OR, 3.67), hypoalbuminemia (P = .04; OR, 3.70), high levels of anti-BP180 antibodies (>112.4 U/mL; P = .003; OR, 6.43), and season (spring: reference; summer: P = .002; OR, 23.58; autumn: P = .02; OR, 12.19; winter: P = .02; OR, 13.19) were significantly associated with BSIs.

CONCLUSIONS

Hospitalized patients with BP had a high incidence of BSIs, and those patients with underlying risk factors require careful management to prevent and control BSIs.

Recent developments in the pathogenesis of pruritus in bullous pemphigoid

Bullous pemphigoid (BP) is a common autoimmune bullous disease which mainly affects the elderly. The incidence of BP is gradually increasing and associated with high mortality. This disease is clinically characterized by intensely pruritic and widespread bullous lesions. Alternative therapy options for pruritus in patients with BP are limited primarily because pathophysiological mechanisms of itching in BP are still unclear. This review aims to explain crucial concepts of the pathogenesis of pruritus in BP. Vital findings in recent years will be summarized, and cofactors of the pathogenesis of pruritus will be discussed in detail. We will summarize knowledge on pathogenic factors in the immunologic level conducing to skin pruritus in BP.

Risk Factors for Mucosal Involvement in Bullous Pemphigoid and the Possible Mechanism: A Review

Bullous pemphigoid (BP) is the most common type of autoimmune bullous disease and is characterized by the presence of circulating anti-BP180 and/or anti-BP230 autoantibodies. Patients with BP often present with tense blisters and erythema, mainly on the trunk and limbs, but a few patients also have mucosal involvement. In this article, we discuss the fact that BP patients with mucosal involvement tend to have more serious conditions and their disease is more difficult to control. Potential risk factors for mucous involvement include earlier age at onset, drugs such as dipeptidyl peptidase-4 inhibitors, cancer, and blood/serum biomarkers, including lower eosinophil count, higher erythrocyte sedimentation rate, IgG autoantibodies against both the NH₂- and COOH-termini of BP180, and the absence of anti-BP230 antibodies. IgA and C3 deposition at the dermo-epidermal junction may also be present. Understanding these risk factors may benefit earlier diagnosis of these patients and promote the development of novel treatments. What's more, it's helpful in deeper understanding of BP development and the relationship between BP and mucous membrane pemphigoid (MMP).

In vitro diagnostics for the medical dermatologist. Part I: Autoimmune tests

Despite the expansion of available in vitro laboratory tests at a rate far exceeding that of dermatologic pharmaceuticals, the existing literature is dominated by discussion of the latter. With the advent of numerous new tests, it can be difficult for practicing dermatologists to stay up-to-date on the available options, methodologies, and recommendations for when to order one test over another. Understanding the inherent strengths and weaknesses of these options is necessary to inform appropriate ordering and proper interpretation of the results. The first article in this continuing medical education series summarizes information on methodology, test characteristics, and limitations of several in vitro laboratory tests used for the work up of undifferentiated patients suspected of having dermatologic autoimmune diseases and it provides a general guide to ordering these tests.

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 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.

Circulating Eosinophil and Neutrophil Counts Correlate with Disease Severity in Bullous Pemphigoid

Background

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized by tissue-bound and circulating autoantibodies directed against BP180 and/or BP230 antigens. Various inflammatory cells are involved in the development of blister in BP.

Objective

The aim of this study was to evaluate the correlation between peripheral leukocyte counts and BP severity.

Methods

We retrospectively included 60 patients with BP, who had not been treated with systemic steroid at the time of blood sampling. The patients were classified into two groups, those with admission history (admission group) and those without admission history (non-admission group). Disease severity was evaluated using three parameters: admission history, initial steroid dosage, and modified version of a pemphigus scoring system. We evaluated the correlation between peripheral leukocyte counts and disease severity measured by the three parameters.

Results

The admission group showed a significant increase in disease severity measured by initial steroid dosage and severity score compared with the non-admission group. Additionally, the admission group had increased total leukocyte, eosinophil, and neutrophil counts. In the correlation study, the peripheral eosinophil and neutrophil counts showed positive correlation with BP severity evaluated by both initial steroid dosage and the pemphigus scoring system.

Conclusion

Peripheral eosinophil and neutrophil counts can be used as a marker in predicting disease severity in patients with BP.

Autoimmune Subepidermal Bullous Diseases of the Skin and Mucosae: Clinical Features, Diagnosis, and Management

Autoimmune subepidermal blistering diseases of the skin and mucosae constitute a large group of sometimes devastating diseases, encompassing bullous pemphigoid, gestational pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, and anti-p200 pemphigoid. Their clinical presentation is polymorphic. These autoimmune blistering diseases are associated with autoantibodies that target distinct components of the basement membrane zone of stratified epithelia. These autoantigens represent structural proteins important for maintenance of dermo-epidermal integrity. Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease of the skin and mucosae. Although the disease typically presents with a generalized blistering eruption associated with itch, atypical variants with either localized bullous lesions or "non-bullous" presentations are observed in approximately 20% of patients. A peculiar form of BP typically associated with pregnancy is pemphigoid gestationis. In anti-p200 pemphigoid, patients present with tense blisters on erythematosus or normal skin resembling BP, with a predilection for acral surfaces. These patients have antibodies targeting the 200-kDa basement membrane protein. Epidermolysis bullosa is a rare autoimmune blistering disease associated with autoantibodies against type VII collagen that can have several phenotypes including a classical form mimicking dystrophic epidermolysis bullosa, an inflammatory presentation mimicking BP, or mucous membrane pemphigoid-like lesions. Mucous membrane pemphigoid (MMP) is the term agreed upon by international consensus for an autoimmune blistering disorder, which affects one or more mucous membrane and may involve the skin. The condition involves a number of different autoantigens in the basement membrane zone. It may result in severe complications from scarring, such as blindness and strictures. Diagnosis of these diseases relies on direct immunofluorescence microscopy studies and immunoserological assays. Management of affected patients is often challenging. We will here review the clinical and immunopathological features as well as the pathophysiology of this group of organ-specific autoimmune diseases. Finally, we will discuss the diagnostic approach and the principles of management in clinical practice.

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.

BPDAI and ABSIS correlate with serum anti-BP180 NC16A IgG but not with anti-BP230 IgG in patients with bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune bullous disease characterized by autoantibody production against BP180 and BP230. Two scoring systems have been validated for BP including: Bullous Pemphigoid Disease Area Index (BPDAI) and Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). In this study, we investigated correlations between both scoring systems and either anti-BP180 NC16A or anti-BP230 values. BPDAI and ABSIS were used to measure disease activity in 95 BP patients at Razi Hospital in Tehran, Iran. ELISA was performed on patient sera to identify any significant relationship between anti-BP180 NC16A/anti-BP230 values and BP disease activity. The two scores showed a strong correlation (ρ = 0.73; p value < 0.0001). Anti-BP180 NC16A values correlated with BPDAI (ρ = 0.49, p value = 0.0001), ABSIS (ρ = 0.47, p value < 0.0001), and BPDAI-Pruritus scores (ρ = 0.29, p value < 0.005). There was a strong correlation between anti-BP180 NC16A values and the ABSIS Skin score (ρ = 0.58, p value < 0.0001), and a moderate correlation with erosion/blister BPDAI score (ρ = 0.48, p value < 0.001) and urticaria/erythema BPDAI score (ρ = 0.27, p value = 0.009). Anti-BP230 values did not demonstrate any relationship with either scores or their subcomponents. Both scoring systems demonstrated moderate validity. Mucosal components did not show any correlation with anti-BP antibodies and are disproportionately presented in both BP scoring tools.

Diagnostic value of autoantibody titres in patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease of the skin requiring skin and serum tests for a precise diagnosis.

OBJECTIVES

We analysed the sensitivity and specificity of BP-relevant parameters and the value of autoantibody titres during follow-up of BP patients.

MATERIALS & METHODS

In a retrospective single-centre study, we included 200 consecutive patients with BP and 400 non-BP patients, and evaluated the test results of patients' serum and skin. In addition, we followed patients' autoantibody titres and clinical characteristics.

RESULTS

BP180-ELISA revealed the highest sensitivity (85.0%; specificity: 93.9%), while BP230-ELISA demonstrated the lowest sensitivity (55.5%; specificity: 92.9%). Direct and indirect immunofluorescence showed comparable results for sensitivity (77.2%/72.7%) and specificity (94.9%/93.7%). The sensitivity for skin histology was 76.3% (specificity: 81.3%). Longitudinal analysis showed significant changes in autoantibody titres.

CONCLUSIONS

BP diagnostics should include serum tests for BP autoantibodies and skin immunofluorescence. Skin histology is supportive for diagnosis. Autoantibody titres are markers for disease activity.

Rituximab therapy in pemphigus and other autoantibody-mediated diseases

Rituximab, a monoclonal antibody targeting the B cell marker CD20, was initially approved in 1997 by the United States Food and Drug Administration (FDA) for the treatment of non-Hodgkin lymphoma. Since that time, rituximab has been FDA-approved for rheumatoid arthritis and vasculitides, such as granulomatosis with polyangiitis and microscopic polyangiitis. Additionally, rituximab has been used off-label in the treatment of numerous other autoimmune diseases, with notable success in pemphigus, an autoantibody-mediated skin blistering disease. The efficacy of rituximab therapy in pemphigus has spurred interest in its potential to treat other autoantibody-mediated diseases. This review summarizes the efficacy of rituximab in pemphigus and examines its off-label use in other select autoantibody-mediated diseases.

Correlation of autoantibodies against BP180/BP230 in response to topical corticosteroids in patients with bullous pemphigoid

Topical steroids are effective in treating bullous pemphigoid (BP). Autoantibodies against BP180 are related to disease activity, but correlation of these autoantibodies with response to topical steroid therapy has not yet been clearly evaluated. We investigate the usefulness of close and early monitoring of autoantibodies against BP180 and BP230 for assessment of response to therapy and early detection of therapeutic failure in BP patients treated topically. In eight BP patients under treatment with topical or systemic steroid therapy we retrospectively evaluated clinical course and autoantibodies against BP180 and BP230 as well as indirect immunofluorescence titres (IIF). Data were included at diagnosis, during hospitalization and follow-ups. Autoantibodies against BP180 parallel disease activity in all topically and as well as systemically treated patients. Autoantibodies against BP230 correlated in five out of eight patients. Autoantibodies directed against BP180 and, to a lesser degree, against BP230 correlate with the clinical course of topically treated BP patients. Monitoring autoantibodies against BP180 is a useful tool to evaluate the efficacy of topical therapy in BP.

Serum levels of immunoglobulins G1 and G4 targeting the non-collagenous 16A domain of BP180 reflect bullous pemphigoid activity and predict bad prognosis

Bullous pemphigoid (BP) is an autoimmune subepidermal bullous disease, and different immunoglobulin (Ig)G autoantibody subclasses may play different roles in the pathogenesis of BP. This study aims to evaluate the relationship between specific IgG subclasses and BP. Enzyme-linked immunoassays (ELISA) were developed to test the IgG subclasses targeting the non-collagenous 16A (NC16A) domain of BP180. A statistical analysis was carried out to assess the relationship of BP and IgG subclasses as well as other factors. The correlation coefficients between the ELISA scores for four IgG subclasses and disease severity scores were 0.586 for IgG, 0.441 for IgG1, 0.594 for IgG2, 0.345 for IgG3, and 0.448 for IgG4 before treatment. After treatment, the correlation coefficient was 0.376 for IgG, 0.522 for IgG1, 0.314 for IgG2, 0.582 for IgG3 and 0.503 for IgG4. Spearman's rank correlation coefficient was 0.801 for IgG1, 0.66 for IgG2, 0.575 for IgG3 and 0.463 for IgG4 between the ELISA scores of IgG subclasses and the disease severity score variation. The ELISA scores of IgG subclasses in patients with mucosal involvement were higher than those without. Survival analysis showed that sex, IgG1 and IgG4 were the independent predictors for BP. In conclusion, the serum levels of IgG1 and IgG4 targeting BP180NC16A were paralleled with disease severity in BP patients. IgG1 and IgG4 and sex were the independent prognostic factors for an early prognosis of BP.

Advances in understanding and managing bullous pemphigoid

Bullous pemphigoid (BP) is the commonest subtype of autoimmune blistering disease in most countries of the world. It occurs most frequently in elderly patients and is characterised clinically by large, tense blisters in the skin preceded by urticarial plaques and pruritus. Immunopathologically, it is characterised by autoantibodies directed against the 180 kD antigen (BP180) and the 230 kD antigen (BP230). New knowledge regarding BP is being continually uncovered. This article reviews the recent advances in BP, including newer diagnostic tests, standardised outcome measures and emerging therapeutic options, as well as the evidence supporting their use.

Positive Direct Immunofluorescence Is of Better Value than ELISA-BP180 and ELISA-BP230 Values for the Prediction of Relapse after Treatment Cessation in Bullous Pemphigoid: A Retrospective Study of 97 Patients

BACKGROUND

ELISA-BP180 values and direct immunofluorescence (DIF) are prognostic factors for relapse after treatment cessation in bullous pemphigoid (BP).

OBJECTIVE

To determine the relevance of ELISA-BP230 antibodies for predicting relapse 6 months after treatment cessation.

METHODS

We retrospectively selected patients with BP and available data from ELISA-BP180 and -BP230 and DIF performed at treatment cessation. The rate of relapse was calculated at 6 months. We compared ELISA-BP180 and -BP230 values and DIF in patients with relapse and remission.

RESULTS

We included 97 patients. At 6 months, 25.6% of patients showed relapse. The proportion of patients with an ELISA-BP230 value ≥27 UA/ml was higher, but not significantly, for those with relapse than for those with remission (p = 0.11). The frequency of positive DIF findings was significantly higher for patients with relapse (p = 0.005).

CONCLUSION

DIF is of better value than ELISA-BP180 and -230 tests to predict relapse after treatment cessation in BP.

Diagnostic accuracy of BP180 NC16a and BP230-C3 ELISA in serum and saliva of patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is a subepidermal blistering disease, characterized by autoantibodies directed against BP180 and BP230. Collecting saliva is an easy and painless way of obtaining biological samples, and can be used for diagnosis of autoimmune diseases.

AIM

To compare the diagnostic accuracy of serum and salivary BP180-NC16a and BP230-C3 in the initial diagnosis of BP.

METHODS

We assessed 50 patients newly diagnosed with BP and 50 healthy controls. The diagnosis of BP was confirmed based on clinical, histopathological and immunofluorescence findings. Serum and saliva samples were collected from both groups, and BP180 and BP230 titres were assessed using commercially available ELISA kits.

RESULTS

Using serum, the sensitivity of the serum BP180 and BP230 ELISA assays was 88% and 48%, respectively, and the specificity of both was 96%. Using saliva with the cutoff value proposed by the manufacturer, sensitivity was 56.2% and 14.6%, and specificity was 98% and 100%, respectively. Using the best calculated cutoff for saliva, sensitivity increased to 87.5% and 77.1%, and specificity to 96% and 62%, respectively. There was a significant correlation between serum and saliva BP180 levels and the severity of skin disease. Both serum and saliva BP230 levels were significantly higher in patients with mucosal involvement.

CONCLUSION

Serum BP180 NC16a ELISA is a sensitive and specific test for the initial diagnosis of BP, whereas serum BP230-C3 ELISA is highly specific, but less sensitive. Saliva may be a noninvasive and convenient alternative for use in the BP180 NC16a ELISA to diagnose BP.

Is there a role for the detection of autoantibodies in the clinical practice of treating infants with bullous pemphigoid? A case report

We present a case of infantile bullous pemphigoid (BP) triggered by primary infection with varicella zoster virus and we analyze the correlation between autoantibody levels and disease activity. With this report we suggest that serum autoantibody titers may not necessarily mirror the clinical course of the disease or represent a helpful tool in guiding therapeutic decisions in infantile BP.

Assessment of bullous pemphigoid disease area index during treatment: a prospective study of 30 patients

BACKGROUND

Recently, a consensus Bullous Pemphigoid Disease Area Index (BPDAI) was proposed to measure therapeutic outcomes in bullous pemphigoid (BP).

OBJECTIVE

To compare BPDAI with other clinical parameters of disease activity at baseline and to describe the variations of BPDAI during the initial phase of treatment.

METHODS

Thirty BP patients were included and followed for 1 year. BPDAI was assessed at baseline and on days 30, 90 and 360 by the same investigator. Concomitantly, the number of daily new blisters, the skin surface area of erythematous/eczematous/urticarial plaques and blisters/erosions, total lesion area (TLA), pruritus score and mucosal involvement were recorded.

RESULTS

At baseline, BPDAI was 46.7 ± 25 (mean ± SD); it was well correlated with erythematous/eczematous/urticarial skin surface (r = 0.63), TLA (r = 0.83), number of daily new blisters (r = 0.7; p ≤ 0.0002) and anti-BP180 autoantibodies (r = 0.49; p = 0.006), but not with anti-BP230 autoantibodies. For the 8 patients with severe BP at baseline, the mean BPDAI was 76.5, versus 35.9 for moderate BP (p = 0.0007). A value of 56 was proposed as a cut-off value for severe BP. BPDAI decreased to 11.9 ± 8.7, 10.7 ± 12.7 and 2.5 ± 4.1 on days 30, 90 and 360, respectively.

CONCLUSION

BPDAI rapidly decreased during the early treatment stage of BP with variations almost totally conditioned by the skin activity component.

Comparative study of direct and indirect immunofluorescence and of bullous pemphigoid 180 and 230 enzyme-linked immunosorbent assays for diagnosis of bullous pemphigoid

BACKGROUND

Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) are used for the laboratory diagnosis of bullous pemphigoid (BP).

OBJECTIVE

The diagnostic value of DIF and IIF on rabbit and monkey esophagus or human salt-split skin and commercial ELISAs was assessed.

METHODS

This was a single-center retrospective study where 313 patients with BP were compared with 488 control subjects.

RESULTS

DIF was the most sensitive test (90.8%) whereas sensitivities for IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 76.0%, 73.2%, 73.3%, 72.0%, and 59.0%, respectively. The sensitivity of the serologic tests was 88.8% altogether. The specificities for DIF, IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 98%, 96.5%, 97.1%, 100%, 94.1%, and 99.2%, respectively.

LIMITATIONS

The retrospective nature of study was a limitation. Correlation of diagnostic data with clinical manifestations or disease course was not possible.

CONCLUSIONS

In suspected BP, both serologic tests and DIF have to be performed because of a sensitivity issue. Although the ELISAs had a relatively low sensitivity, the serologic tests altogether almost reached the level of sensitivity of DIF. The specificities of all assays were excellent.

Biochip technology for the serological diagnosis of bullous pemphigoid

Bullous pemphigoid is an autoimmune blistering skin disease characterized by the presence of circulating autoantibodies which recognize specific proteins of the epidermis and dermoepidermal junction. Diagnosis is based on clinical criteria and laboratory investigations, notably histology, direct and indirect immunofluorescence, and ELISA. This study describes a new immunofluorescence assay for parallel determination of anti-BP180 and anti-BP230 based on recombinant antigenic substrates. The aim of the study was to detect BP180 and BP230 autoantibodies by BIOCHIP technology using both a specially designed recombinant BP180-NC16A protein and cells expressing the BP230-gc antigen fragment. 18 patients with bullous pemphigoid were included in the study. Autoantibodies to BP180 were detected by the BIOCHIP technique in 83.33% of patients with clinical, serological, and immunohistological confirmed bullous pemphigoid while autoantibodies against BP230-gC were detected only in 39% of patients. The detection of anti-BP180-NC16A and anti-BP230-gC by a new biochip-based immunoassay is a suitable alternative to indirect immunofluorescence and ELISA. This method has the advantage of easily discriminating the different autoantibody specificities. The BIOCHIP method is faster, cheaper, and easy to use when compared with the ELISA approach. For this reason, the new method could be used as an initial screening test to identify patients with bullous pemphigoid, and doubtful results could then be confirmed by ELISA.

Association of autoantibodies to BP180 with disease activity in Greek patients with bullous pemphigoid

39 bullous pemphigoid (BP) patients were studied to assess the clinical significance of anti-BP180 and anti-BP230 circulating autoantibodies of BP and correlate their titers with the clinical scores of the BP Disease Area Index (BPDAI) and the Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) as well as with the intensity of pruritus measured by the BPDAI pruritus component. All parameters were evaluated by the time of diagnosis (baseline), month 3, and month 6. Titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (r = 0.557, P value < 0.0001) and ABSIS (r = 0.570, P value < 0.0001) values, as well as with BPDAI component for the intensity of pruritus (rho = 0.530, P value = 0.001) at baseline. At month 3, titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (rho = 0.626, P value = 0.000) and ABSIS (rho = 0.625, P value = 0.000) values, as well as with the BPDAI component for the intensity of pruritus (rho = 0.625, P value = 0.000). At month 6, titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (rho = 0.527, P value = 0.001) and ABSIS (rho = 0.526, P value = 0.001) values, as well as with the BPDAI component for the intensity of pruritus (rho = 0.525, P value = 0.001). There was no statistically significant correlation between titers of anti-BP230 autoantibodies and the BPDAI, ABSIS, and BPDAI component for the intensity of pruritus at the same time points.

Anti-skin specific autoantibodies detected by a new immunofluorescence multiplex biochip method in patients with autoimmune bullous diseases

BACKGROUND

Autoimmune blistering skin diseases are a heterogeneous group of diseases characterized by autoantibodies against structural components of the skin. In pemphigus vulgaris (PV) autoantibodies react mainly with desmoglein 3 (Dsg3) alone and/or in combination with desmoglein 1 (Dsg1). In bullous pemphigoid (BP) autoantibodies target two hemidesmosomal proteins, BP180 and BP230.

OBJECTIVE

To evaluate the diagnostic accuracy of a new indirect immunofluorescence (IIF) multiplex biochip method for the detection of anti-skin specific autoantibodies.

METHODS

Sera from 36 patients with PV and from 40 patients with BP were collected. The control group included 54 patients with other skin diseases and 40 healthy subjects. The detection of circulating autoantibodies to Dsg1, Dsg3, BP230 and BP180 was performed with a new IIF multiplex biochip method and with two currently commercially available ELISA methods.

RESULTS

The multiplex IIF method showed a high diagnostic sensitivity (100%) for PV on cells transfected with Dsg3. In patients with BP, the positivity to the BP180 antigen was higher (90%) than that on monkey esophagus (50%) and on cells transfected with BP230 (40%). A good rate of agreement was observed among methods (IIF vs. ELISA) and among ELISA systems.

CONCLUSIONS

The new multiplex biochip IIF method has a high diagnostic accuracy for the diagnosis of PV and BP, comparable to ELISA methods, and is able to screen autoimmune bullous diseases.