Mucosal Involvement in Bullous Pemphigoid Is Mostly Associated with Disease Severity and to Absence of Anti-BP230 Autoantibody

Identification of Risk Factors for Gliptin-associated Bullous Pemphigoid among Diabetic Patients

Drug-associated bullous pemphigoid has been shown to follow long-term gliptin (dipeptidyl-peptidase 4 inhibitors) intake. This study aimed at identifying risk factors for gliptin-associated bullous pemphigoid among patients with type 2 diabetes. A retrospective study was conducted in a tertiary centre among diabetic patients exposed to gliptins between the years 2008-2021. Data including demographics, comorbidities, medications, and laboratory results were collected using the MDClone platform. Seventy-six patients with type 2 diabetes treated with dipeptidyl-peptidase 4 inhibitors who subsequently developed bullous pemphigoid were compared with a cohort of 8,060 diabetic patients exposed to dipeptidyl-peptidase 4 inhibitors who did not develop bullous pemphigoid. Based on a multivariable analysis adjusted for age and other covariates, Alzheimer's disease and other dementias were significantly more prevalent in patients with bullous pemphigoid (p = 0.0013). Concomitant use of either thiazide or loop diuretics and gliptin therapy was associated with drug-associated bullous pemphigoid (p < 0.0001 for both). While compared with sitagliptin, exposure to linagliptin and vildagliptin were associated with bullous pemphigoid with an odds ratio of 5.68 and 6.61 (p < 0.0001 for both), respectively. These results suggest gliptins should be prescribed with caution to patients with type 2 diabetes with coexisting Alzheimer's and other dementias, or patients receiving long-term use of thiazides and loop diuretics. The use of sitagliptin over linagliptin and vildagliptin should be preferred in these patients.

Ocular involvement in oral vesiculobullous diseases: A review on reported cases in the literature

Introduction

Vesiculobullous disorders are a group of autoimmune diseases manifesting as chronic ulcers in the oral cavity. Ocular involvement may accompany oral ulcers and cause various problems for patients. This review summarizes the data regarding ocular involvement in patients with oral vesiculobullous.

Methods

Web of Science, Scopus, PubMed/MEDLINE, and Embase electronic databases were searched according to related keywords. Finally, 58 articles were included, all of which were case reports or series. Characteristics such as the age and sex of patients, location and type of oral lesion, type of ophthalmic injury, the interval between oral and ocular lesion, and treatment of oral and ocular disorders were summarized in tables.

Results

Eye involvement was 1.6 times more prevalent in women, and most patients were between 30 and 60 years old (67.4 %). Pemphigus vulgaris accounted for almost half of the cases (48.4 %), though lichen planus is more prevalent in the general population. The most frequently affected oral site was the buccal mucosa (17.5 %), and oral ulcers usually presented as erythema, erosion, or inflammation (22.7 %). Conjunctivitis was the most common type of eye involvement (18.4 %), and ophthalmic lesions regularly appeared 12-60 months after the development of oral lesions (30.1 %). Blindness was reported in only one case. Corticosteroids and immunosuppressives were the most frequent oral and ocular lesion therapies.

Conclusion

Considering the serious burdens of any ocular injury, monitoring the ocular health of patients with oral vesiculobullous diseases is highly recommended in high-risk cases, especially middle-aged women with oral pemphigus vulgaris.

From Molecular Insights to Clinical Perspectives in Drug-Associated Bullous Pemphigoid

Bullous pemphigoid (BP), the most common autoimmune blistering disease, is characterized by the presence of autoantibodies targeting BP180 and BP230 in the basement membrane zone. This leads to the activation of complement-dependent and independent pathways, resulting in proteolytic cleavage at the dermoepidermal junction and an eosinophilic inflammatory response. While numerous drugs have been associated with BP in the literature, causality and pathogenic mechanisms remain elusive in most cases. Dipeptidyl peptidase 4 inhibitors (DPP4i), in particular, are the most frequently reported drugs related to BP and, therefore, have been extensively investigated. They can potentially trigger BP through the impaired proteolytic degradation of BP180, combined with immune dysregulation. DPP4i-associated BP can be categorized into true drug-induced BP and drug-triggered BP, with the latter resembling classic BP. Antineoplastic immunotherapy is increasingly associated with BP, with both B and T cells involved. Other drugs, including biologics, diuretics and cardiovascular and neuropsychiatric agents, present weaker evidence and poorly understood pathogenic mechanisms. Further research is needed due to the growing incidence of BP and the increasing identification of new potential triggers.

Mixed muco-cutaneous pemphigoid: Clinical and immunological features of 15 cases

Introduction

We describe a series of patients whose auto-immune bullous skin disease (AIBD) of the dermal-epidermal junction (DEJ) was characterized by clinical, immunological and ultrastructural features intermediate between bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP), and a recalcitrant course.

Patients and Methods

From the database of the French reference centre for AIBD, we screened all the patients who were referred for an AIBD of the DEJ with a mucosal involvement, who neither met the diagnostic criteria for the diagnosis of BP, nor were typical of MMP. Sera were analysed by NC16A-ELISA and immunobloting against the C-terminal and LAD-1 parts of BP180. Skin biopsies were studied by direct immunoelectron microscopy (IEM).

Results

Fifteen patients (4 males, 11 females) of mean age 70.8 ± 11.8 years were included. The mucosal involvement was localized in oral cavity in all cases and in pharyngeal/laryngeal or genital area in 8 (53%), and 6 patients (40%), respectively. No patient had ocular involvement, nor atrophic or fibrosing scars. All patients had extensive skin lesions (mean BPDAI score =65.9 ± 24.4), which predominated on the upper body part. Direct IEM performed on 8 patients showed IgG deposits on the lamina lucida in all cases, and the lamina densa in 5 cases. All sera recognized NC16A, while none recognized BP-230 in ELISA. 10 out of the 13 tested sera (76.9%) contained IgG which recognized the C-terminal domain of BP180 and 10 sera (76.9%) the LAD-1 domain of BP180. Patients poorly responded to super potent topical corticosteroids and were treated with oral corticosteroids ± immunosuppressant in 13 cases (86.6%).

Conclusion

This mixed muco-cutaneous pemphigoid differs from BP by the younger age of patients, multiple mucosae involvement, circulating antibodies against both the C- and N-terminal part of BP180, and very poor response to topical CS. It differs from MMP by extensive inflammatory skin lesions, absence of ocular involvement and atrophic/fibrosing scars.

A Review of Bullous Dermatologic Adverse Events Associated with Anti-Cancer Therapy

The rapid evolution of anti-cancer therapy (including chemotherapy, targeted therapy, and immunotherapy) in recent years has led to a more favorable efficacy and safety profile for a growing cancer population, and the improvement of overall survival and reduction of morbidity for many cancers. Anti-cancer therapy improves outcomes for cancer patients; however, many classes of anti-cancer therapy have been implicated in the induction of bullous dermatologic adverse events (DAE), leading to reduced patient quality of life and in some cases discontinuation of life-prolonging or palliative therapy. Timely and effective management of adverse events is critical for reducing treatment interruptions and preserving an anti-tumor effect. Bullous DAE may be limited to the skin or have systemic involvement with greater risk of morbidity and mortality. We present the epidemiology, diagnosis, pathogenesis, and management of bullous DAE secondary to anti-cancer therapies to enable clinicians to optimize management for these patients.

Bullous pemphigoid: Three main clusters defining 3 outcome profiles

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disorder. Its presentation is polymorphic.

OBJECTIVE

To investigate different clinical and biological profiles of BP.

METHODS

We conducted a retrospective 2-center study including all BP patients seen between January 1, 2015, and February 28, 2021. We performed hierarchical clustering on principal components.

RESULTS

Three clusters were identified. Patients in cluster 1 (n = 155) were older than those in clusters 2 (n = 89) and 3 (n = 35; P < .0001), more frequently presented pauci-bullous BP (n = 63 [41%] vs 14 [16%] and 2 [6%], respectively; P < .0001) and had anti-BP230 antibodies in 87% of cases. More than 100 blisters were observed in 14 patients (40%) from cluster 3, versus 3 (2%) from cluster 1 and 0 (0%) from cluster 2 (P < .0001). Frequency of mucosal involvement was higher in cluster 3 (n = 32 [91%, including epiglottis in 40%] vs 11 [7%] and 34 [38%]; P < .0001). In clusters 2 and 3, 70% and 74% of patients had antibodies targeting only BP180. Those in cluster 3 received more lines of systemic treatment and experienced more relapses.

LIMITATIONS

Retrospective study without immunoelectron microscopy.

CONCLUSION

We identified 3 different BP clusters, including one corresponding to severe BP180⁺ BP230^- BP with features common to mucous membrane pemphigoid.

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.

Immunological features and factors associated with mucocutaneous bullous pemphigoid - a retrospective cohort study

BACKGROUND AND OBJECTIVES

The features of bullous pemphigoid (BP) patients presenting with mucosal lesions are not established. We aimed to elucidate the clinical and immunological features of BP patients with mucosal involvement, and to identify factors associated with mucosal lesions.

PATIENTS AND METHODS

A retrospective study encompassing all consecutive patients diagnosed with BP throughout the years 2009-2019 in a tertiary referral center.

RESULTS

The study encompassed 273 patients with BP, of whom 31 (11.4 %) presented with mucosal lesions. The oral mucosa was the most frequently affected mucosal surface (71.0 %), followed by the genital (25.8 %) and the nasal (22.6 %) mucosae. Relative to other patients with BP, patients with mucosal involvement had a more prominent palmoplantar involvement (67.7 % vs. 37.2 %; P = 0.001); lower seropositivity rate (18.2 % vs. 54.2 %; P = 0.027) and lower levels (29.3 ± 64.5 vs. 129.5 ± 304.4 U/ml; P = 0.016) of anti-BP230 autoantibodies; and decreased peripheral eosinophil counts (760.0 ± 638.6 vs. 1296.3 ± 1013.7; P < 0.001). Absence of anti-BP230 autoantibodies (OR, 5.32; 95 % CI, 1.07-26.32; P = 0.026) and lack of peripheral eosinophilia (OR, 4.31; 95 % CI, 1.14-16.39; P = 0.021) were associated with the presence of mucosal involvement in BP.

CONCLUSIONS

Mucosal involvement is present in a notable subgroup of patients with BP and is associated with the absence of both anti-BP230 antibodies and peripheral eosinophilia.

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).

Therapy of autoimmune mouth bullous disease: 2020 review

Most diseases of oral mucosa are either autoimmune in nature or are the results of immunologically mediated events. The diseases with autoimmune pathogenesis are namely pemphigus and pemphigoid; the oral involvement is frequent or regularly observed in these diseases. The treatments with traditional drugs or biologic agents or combinations of these molecules are employed in clinical practice. New therapeutic targets aim to provide new treatment strategies that may go beyond nonspecific immunosuppression.

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.

Correlation of dermal and blood eosinophilia with bullous pemphigoid disease severity

Background

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease associated with immune response against BP-180 and BP-230. Peripheral blood eosinophilia and dermal infiltration of eosinophils are common findings in BP.

Objective

The aim of our study was to demonstrate a statistical correlation between dermal and peripheral blood eosinophilia, anti BP-180, and anti BP-230 IgG and clinical severity of BP.

Methods

A total of 27 patients with newly diagnosed BP were included. Severity of disease was assessed according to the bullous pemphigoid disease activity index (BPDAI). Anti-BP-180 and anti-BP-230 titers, peripheral blood eosinophilia, and dermal eosinophil infiltration and tissue inflammation severity were assessed for each patient.

Results

A significant correlation was found between the serum levels of anti-BP-180 and anti-BP-230, and dermal eosinophilia and tissue inflammation severity with objective and subjective BPDAI scores. In addition, there was a significant correlation between the percentage of peripheral blood eosinophils and subjective BPDAI scores and urticarial/eczematous lesions. Moreover, the mucosal component did not show any correlation with autoantibody levels and inflammation severities.

Conclusion

Anti-BP-180 and anti-BP-230 levels, tissue inflammation severity, and dermal eosinophilia had a strong and significant correlation with BP severity. In addition, percentage of peripheral blood eosinophilia showed a correlation with subjective BPDAI scores.

Anti-p200 Pemphigoid: A Systematic Review

The many clinical aspects of anti-p200 pemphigoid are not well-characterized. We aimed to analyze and correlate known existing data on the epidemiological, clinical, histological, and immunological features of anti-p200 pemphigoid. We performed a review using Medline, Embase, and Web of Science databases (1900–2018). Case reports and series of patients were included. A total of 68 eligible studies that comprised 113 anti-p200 pemphigoid patients were included in the qualitative analysis, where there was a mean age of onset of 65.5 years. All patients presented with bullae/vesicles, and 54.3% had urticarial plaques. A similarity to bullous pemphigoid was reported in 66.1% of cases, but palmoplantar (51.4%), cephalic (40.3%), and mucosal (38.5%) involvement, besides frequent development of scars/milia (15.7%), were reported. Autoantibodies against recombinant laminin γ1 were detected in the sera of 73.1% of patients. Psoriasis was present in 28.3% of anti-p200 pemphigoid patients, particularly among Japanese patients (56.4%). The incidence of pustular psoriasis in this subgroup, was significantly greater than in the normal population. In conclusion, the diagnosis of anti-p200 pemphigoid may be suspected when a subepidermal autoimmune blistering disease develops in a younger age group, along with significant acral and cephalic distribution and mucosal involvement.

Assessment of the Prevalence of Mucosal Involvement in Bullous Pemphigoid

Importance

The prevalence of mucosal involvement in bullous pemphigoid (BP) is inconsistent. Nonoral mucosal involvement was reported anecdotally in few patients with BP.

Objective

To evaluate the prevalence of mucosal involvement in patients with BP, and to characterize the subgroup of patients with mucosal lesions.

Design, Setting, and Participants

A retrospective cohort study was performed including 328 consecutive patients diagnosed with immunopathologically validated BP at a tertiary care referral center for autoimmune bullous diseases in northern Israel between January 1, 2000, and December 31, 2017.

Main Outcome and Measures

The study was conducted to estimate the prevalence and distribution of mucosal involvement among patients with BP. Patients with mucosal involvement were compared with the remaining BP patients regarding clinical and immunological features, laboratory analyses, and treatments.

Results

The study cohort included 139 (42.4%) male and 189 (57.6%) female patients, with a mean (SD) age of 78.0 (11.8) years at presentation. Fifty-six patients (17.1%) presented with mucosal lesions. The oral mucosa was the most frequently affected mucosal surface (n = 44; 13.7%), followed by the laryngeal (n = 16; 4.9%) and the genital (n = 10; 3.0%) mucosae. Among patients with oral lesions, the most involved oral structures were the buccal mucosa (n = 25; 55.6%) and the soft palate (n = 24; 53.3%). Compared with other patients with BP, patients with mucosal involvement were younger (71.8 [14.4] years vs 79.3 [10.8] years; P < .001), presented more frequently with extensive disease (55.4% vs 39.7%; P = .002), had less peripheral eosinophilia (17.8% vs 41.9%; P < .001), and were treated with higher doses of corticosteroids (prednisone >1 mg/kg: 67.9% vs 51.8%; P = .03).

Conclusions and Relevance

Mucosal lesions are present in a notable subgroup of patients with BP and are associated with disease severity. Laryngeal involvement is more common than previously appreciated.

Characteristic Pattern of IL-17RA, IL-17RB, and IL-17RC in Monocytes/Macrophages and Mast Cells From Patients With Bullous Pemphigoid

Inflammation is largely implicated in bullous pemphigoid (BP), the most frequent skin auto-immune blistering disease. IL-17, essentially IL-17A/F, has been involved in blister formation through regulation of protease production, and its specific serum profile within BP was related to disease outcome. However, relationships between IL-17 family ligands and receptors are quite complex with six different IL-17 isoforms, and five different receptors. We here aimed at clarifying the contribution of the IL-17 axis in BP by characterizing not only the expression of IL-17 receptor (IL-17R) members within immune cells isolated from BP patients (PMNs, n = 9; T-lymphocytes, n = 10; and monocytes, n = 10) but also the expression of IL-17 isoforms in sera (n = 83), and blister fluid (n = 31) of BP patients. We showed that at diagnosis, IL-17RA and IL-17RC expression were significantly increased in monocytes isolated from BP patients as compared to those from control subjects (p = 0.006 and p = 0.016, respectively). Notably, both IL-17RA and IL-17RC mRNA expression remained elevated in BP monocytes at time of relapse. We further demonstrated a significant increase of all IL-17 isoforms tested in BP blister fluid compared with BP serum (IL-17A, p < 0.0001; IL-17A/F, p < 0.0001; IL-17B, p = 0.0023; IL-17C, p = 0.0022; IL-17E, p < 0.0001). Among all, IL-17B was the only cytokine for which a significant decreased concentration within blister fluid was observed in BP patients with severe disease compared to patients with moderate disease (p = 0.012). We further evidenced a significant negative correlation between IL-17B levels and blister/erosion BPDAI subscore (r = −0.52, p = 0.003). We finally identified mast cells as a potential target of IL-17B in lesional skin of BP patients. In conclusion, we showed here that IL-17RA and IL-17RC expression in monocyte was associated with disease activity and evidenced in situ a negative correlation between BP disease activity and IL-17B, whose effects could be mediated by IL-17RB expressed by mast cell in BP lesional skin.

Association of Transient Palmoplantar Keratoderma With Clinical and Immunologic Characteristics of Bullous Pemphigoid

Importance

Development of transient palmoplantar keratoderma (PPK) with bullous pemphigoid (BP) has only been described in 2 isolated case reports. The clinical significance and the pathophysiologic mechanisms of this association are unknown.

Objective

To examine the clinical characteristics and immunological profile of patients with BP who develop transient PPK and analyze therapeutic options and outcomes.

Design, Setting, and Participants

In this case series, patients with BP who developed acquired, transient PPK, and were treated at a single institution from January 1, 2015, through December 31, 2017, were studied.

Main Outcomes and Measures

Clinical and immunological activity of BP, treatment administrated before and after PPK appearance, and patient outcomes.

Results

Six patients with BP and transient PPK were identified and included in the study. There were 5 women and 1 man with a mean age of 72 years. At baseline, all patients had a generalized, multibullous BP and high serum anti-BP180 antibodies (mean, 130 U/mL; range, 73-150), whereas anti-BP230 antibodies were elevated in only 1 case. The PPK appeared a mean 6.2 (range, 2-12) months after BP diagnosis, following a prolonged period of disease activity with recurrent flares. When the PPK occurred, BP was uncontrolled on therapy (mean Bullous Pemphigoid Disease Activity Index [BPDAI] score, 57; range, 34-105; mean anti-BP180 antibodies titer, 122 U/mL; range, 81-150). On administration of additional systemic immunosuppressive therapies, the PPK healed progressively in a mean 4.3 months (range, 2-9), along with BP clinical remission in 4 of 6 patients. No relationship was found between PPK occurrence and anti-BP180/230 antibodies profiles. In contrast, blister fluids collected at the time of PPK displayed a much higher level of interleukin 1β (IL-1β) compared with those collected in the absence of PKK. Expression of IL-17A, IL-17F, and IL-22 was also enhanced in the blister fluid of patients with BP who had PPK.

Conclusions and Relevance

To our knowledge, this is the first report of 6 cases of BP with transient PPK with extensive immunological investigation. The PPK appeared after a prolonged period of clinical BP activity punctuated with recurrent relapses, was transient, and healed after BP control with additional immunosuppressive therapy. Enhanced expression of a particular cytokine panel in the blister fluid at time of PPK could support keratinocyte proliferation as described in patients with psoriasis. Transient PPK could represent a clinical marker of severe, treatment-resistant BP.

The Diagnosis and Blistering Mechanisms of Mucous Membrane Pemphigoid

Mucous membrane pemphigoid (MMP) is a mucous membrane-dominated autoimmune subepithelial blistering disease that is caused by autoantibodies against various autoantigens in basement membrane zone (BMZ) proteins, including collagen XVII (COL17). Clinicians face diagnostic problems in detecting circulating antibodies and targeted antigens in MMP. The diagnostic difficulties are mainly attributed to the low titers of MMP autoantibodies in sera and to heterogeneous autoantigens. Additionally, no unanimous diagnostic criteria have been drawn for MMP, which can result in delayed diagnoses or misdiagnoses. This review aims to integrate and present currently available data to clarify diagnostic strategies and to present diagnostic criteria for MMP. The ultimate blistering mechanism in MMP has not been elucidated, and such mechanism is especially obscure in COL17-type MMP. In bullous pemphigoid (BP), which is the most common autoimmune subepidermal blistering disease, some patients show oral lesion as well as predominant skin lesions. However, there is no fundamental explanation for the onset of oral lesions in BP. This article summarizes innovative research perspectives on the pathogenesis of oral lesions in pemphigoid. Finally, we propose a potential pathogenesis for COL17-type MMP.

Diagnosis of Autoimmune Blistering Diseases

Autoimmune skin blistering diseases (AIBD) are characterized by autoantibodies that are directed against structural proteins in the skin and adjacent mucous membranes. Some clinical signs are typical for a specific AIBD, however, correct diagnosis requires the detection of tissue-bound or circulating autoantibodies. The gold standard for diagnosis of AIBD is the detection of autoantibodies or complement component 3 by direct immunofluorescence (DIF) microscopy of a perilesional biopsy. Circulating antibodies can be detected via indirect immunofluorescence (IIF) microscopy of different tissue substrates including human skin, monkey esophagus, and more recently, recombinant forms of the different target antigens. Latter are also employed in various commercial ELISA systems and by immunoblotting in in-house assays available in specialized laboratories. ELISA systems are also particularly valuable for monitoring of the disease activity during the disease course which can be helpful for treatment decisions. Exact diagnosis is essential for both treatment and prognosis, since some AIBD are associated with malign tumors such as paraneoplastic pemphigus and anti-laminin 332 mucous membrane pemphigoid. This review presents clinical and immunopathological features of AIBD for the state-of the art diagnosis of these disorders.

Anti-Type VII Collagen Antibodies Are Identified in a Subpopulation of Bullous Pemphigoid Patients With Relapse

Bullous pemphigoid (BP) is an autoimmune bullous skin disease characterized by anti-BP180 and anti-BP230 autoantibodies (AAbs). Mucous membrane involvement is an uncommon clinical feature of BP which may evoke epidermolysis bullosa acquisita, another skin autoimmune disease characterized by anti-type VII collagen AAbs. We therefore evaluated the presence of anti-type VII collagen AAbs in the serum of BP patients with and without mucosal lesions at time of diagnosis and under therapy. Anti-BP180, anti-BP230, and anti-type VII collagen AAbs were measured by ELISA in the serum of unselected patients fulfilling clinical and histo/immunopathological BP criteria at baseline (n = 71) and at time of relapse (n = 24). At baseline, anti-type VII collagen AAbs were detected in 2 out of 24 patients with BP presenting with mucosal involvement, but not in patients without mucosal lesions (n = 47). At the time of relapse, 10 out of 24 BP patients either displayed a significant induction or increase of concentrations of anti-type VII collagen AAbs (P < 0.01), independently of mucosal involvement. Those 10 relapsing BP patients were also characterized by a sustained high concentration of anti-BP180 AAb, whereas the serum anti-BP230 AAb concentrations did not vary in BP patients with relapse according to the presence of anti-type VII collagen AAbs. Thus, our study showed that anti-type VII collagen along with anti-BP180 AAbs detection stratified BP patients at time of relapse, illustrating a still dysregulated immune response that could reflect a potential epitope spreading mechanism in those BP patients.