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.

Analysis of the Clinical Characteristics of Dipeptidyl Peptidase-4 Inhibitor-Induced Bullous Pemphigoid.

OBJECTIVE: To analyze and discuss the clinical characteristics of dipeptidyl peptidase-4 inhibitor (DPP4i)-induced bullous pemphigoid (BP). DATA SOURCES: We collected case reports of DPP4i-induced BP by searching databases from 2006 to mid-May 2021, as a retrospective analysis. STUDY SELECTION AND DATA EXTRACTION: Relevant case reports and case analyses of DPP4i-induced BP were included. DATA SYNTHESIS: The median time of symptom onset was 9 months (range 0.5-59 months). BP most often occurred in patients receiving vildagliptin (52.63%) followed by linagliptin (27.19%) and sitagliptin (17.54%). Tense bullae and blisters (85.51%) and erythema (82.61%) on the extremities and trunk were the most common presenting symptoms. In total, 64.06% of BP patients were anti-BP180 autoantibody positive, 58.97% were BP180NC16a autoantibody positive, and 31.25% were anti-BP230 autoantibody positive. Skin biopsy revealed subepidermal bulla eosinophil infiltration in 93.85% of BP patients, lymphocyte infiltration in 56.93%, and neutrophil infiltration in 44.62%. Direct immunofluorescence was positive in 98.94% of BP patients with linear deposition of IgG (97.80%) and/or complement C3 (98.94%) along the basement membrane zone. Indirect immunofluorescence was positive in 87.88% of BP patients. Complete remission of BP was achieved in 83.64% of patients on DPP4i withdrawal and after 4 months (range 0.13-72 months) of follow-up. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This review analyzes and discusses the clinical characteristics of DPP4i-induced BP and provides a reference for the safe and reasonable clinical application of DPP4i. CONCLUSIONS: DPP4i drugs are related to the occurrence of BP in diabetic patients, especially elderly men taking vildagliptin.

Challenges and pitfalls between lichen planus pemphigoides and bullous lichen planus.

Lichen planus pemphigoides (LPP) and bullous lichen planus (BLP) are rare dermatoses, which are characterised by blisters and lichenoid lesions. Their clinical presentation is heterogenous, displaying overlapping features or mimicking other dermatological diseases. Therefore, diagnosis can often be challenging, requiring a thorough dermatological examination along with distinctive histological and immunopathological characteristics. Lichenoid degeneration of the basal epidermis exposes various antigens of the dermal-epidermal junction in LPP, resulting in the breakdown of immune tolerance, hence, the production of autoantibodies against type XVII collagen. Conversely, no pathogenic autoantibodies are detected in BLP. However, some cases of mucosal lichen planus might display immunopathological features suggestive of autoimmune blistering diseases. Therefore, a better understanding of the pathophysiology of these two distinct dermatoses is imperative. The aim of this review was to provide a summary of the current knowledge on the clinical hallmarks, diagnosis and available therapeutic options in LPP and BLP.

Bullous Pemphigoid-Associated Mortality Rate in a Canadian Tertiary Referral Centre.

BACKGROUND: Bullous pemphigoid (BP) is the most common autoimmune blistering disorder in adults. Most individuals with BP are over the age of 60. Its worldwide incidence has been increasing owing to population aging. Observational studies published over the last 2 decades highlight the non-negligible, albeit variable overall mortality of BP patients, with reported 12-month mortality rates of 10.8% to 40.8%, and 24-month mortality rates of 20.1% to 51.0%. Data in the Canadian population are lacking. OBJECTIVES: We aimed to estimate the 12- and 24-month overall mortality rate of Canadian patients diagnosed with BP, and to identify independent risk factors adversely impacting overall survival. METHODS: A retrospective cohort study of 166 patients with a diagnosis of BP between 2010 and 2020 was carried out at Centre hospitalier de l'Université de Montréal (CHUM), a tertiary referral center in Montréal, Québec, Canada. Cumulative mortality was calculated using the Kaplan-Meier estimator, and independent prognostic factors were identified using a Cox proportional hazards regression model. RESULTS: Eighty-five patients (51.2%) in our study were female. The median age was 79.1 years old, and 80 patients (48.2%) were 80 years old or older. Mortality at 12 and 24 months in our study cohort was 16.2% (CI95% = 10.5 - 21.8) and 27.6% (CI95% = 20.5 - 34.7), respectively. In a multivariate analysis, patients who were male, 80 years old or older, and/or had a diagnosis of a major neurocognitive disorder had a poorer overall survival. CONCLUSIONS: The all-cause mortality of patients with BP in our study population compared favorably with international data reported in the literature.

Autoantibody Detection for Diagnosis in Direct Immunofluorescence-Negative Mucous Membrane Pemphigoid: Ocular and Other Sites Compared.

PURPOSE: To assess whether a panel of serum pemphigoid autoantibody tests could be used to confirm an immunopathologic diagnosis of mucous membrane pemphigoid (MMP) in direct immunofluorescent negative (DIF-) MMP patients. DESIGN: Prospective cross-sectional study. PARTICIPANTS: Seventy-six patients with multisite MMP with 45 matched control participants. METHODS: Enzyme-linked immunosorbent assays (ELISAs) for BP180 and BP230 (MBL International), immunoglobulin A (IgA) A and immunoglobulin G indirect immunofluorescence (IIF) on human salt-split skin and the keratinocyte footprint assay for anti-laminin 332 antibodies. MAIN OUTCOME MEASURES: Sensitivity and specificity of autoantibody detection and significant differences for individual tests and test combinations for MMP involving different sites. RESULTS: All DIF- patients (24/73 [31.8%]) had either ocular-only disease or ocular involvement in multisite disease. Serum pemphigoid autoantibodies were detected in 29 of 76 MMP patients (38.2%) compared with 3 of 45 control participants (6.7%). Autoantibody reactivity detected by any 1 or more of the tests was present in 6 of 24 DIF- patients (25%) compared with 22 of 49 DIF positive (DIF+) patients (44.9%). Ocular-only MMP serum reactivity was not significantly different for any test or test combination compared with control participants, whereas DIF- multisite ocular MMP differed for 1 ELISA and 3 of 7 test combinations. By contrast, for DIF+ nonocular MMP patients, all the individual tests, apart from IgA IIF, and all test combinations were significantly different compared with those for control participants. For the entire MMP cohort, the sensitivity of all individual tests was low, having a maximum of 21.05% for BP180 reactivity but increasing to 38.16% for an optimal test combination. Disease activity was associated strongly with positive serologic findings. CONCLUSIONS: Pemphigoid serum autoantibody tests did not provide immunopathologic evidence of MMP in ocular-only MMP patients but showed limited value in DIF- multisite ocular MMP patients. The requirement for immunopathologic confirmation of MMP by autoantibody detection is inappropriate for DIF- ocular-only MMP patients, resulting in missed diagnoses, delayed therapy, and poor outcomes. Alternative diagnostic criteria for ocular-only MMP are required to exclude the other causes of scarring conjunctivitis until more sensitive and specific immunopathologic tests become available.

Autoimmune bullous skin diseases, pemphigus and pemphigoid.

Autoimmune bullous skin diseases, such as pemphigus and pemphigoid, may enable clarification of the mechanisms of immune regulation in the skin. Pemphigus and pemphigoid are mediated by essentially IgG autoantibodies against structural proteins of the desmosomes at cell-cell junctions and hemidesmosomes at epidermal-dermal junctions, respectively, and are characterized by blisters and erosions in the skin and/or mucous membranes. Intensive investigation over the last 3 decades has identified their target antigens and developed serological diagnostic tools as well as mouse models to help us understand their pathophysiology. Based on these advances, several new therapeutic approaches have become available, and more effective and less toxic targeted approaches are under development.

Disruption of dystonin in Schwann cells results in late-onset neuropathy and sensory ataxia.

Dystonin (Dst) is a causative gene for Dystonia musculorum (dt) mice, which is an inherited disorder exhibiting dystonia-like movement and ataxia with sensory degeneration. Dst is expressed in a variety of tissues, including the central nervous system and the peripheral nervous system (PNS), muscles, and skin. However, the Dst-expressing cell type(s) for dt phenotypes have not been well characterized. To address the questions whether the disruption of Dst in Schwann cells induces movement disorders and how much impact does it have on dt phenotypes, we generated Dst conditional knockout (cKO) mice using P0-Cre transgenic mice and Dst gene trap mice. First, we assessed the P0-Cre transgene-dependent Cre recombination using tdTomato reporter mice and then confirmed the preferential tdTomato expression in Schwann cells. In the Dst cKO mice, Dst mRNA expression was significantly decreased in Schwann cells, but it was intact in most of the sensory neurons in the dorsal root ganglion. Next, we analyzed the phenotype of Dst cKO mice. They exhibited a normal motor phenotype during juvenile periods, and thereafter, started exhibiting an ataxia. Behavioral tests and electrophysiological analyses demonstrated impaired motor abilities and slowed motor nerve conduction velocity in Dst cKO mice, but these mice did not manifest dystonic movements. Electron microscopic observation of the PNS of Dst cKO mice revealed significant numbers of hypomyelinated axons and numerous infiltrating macrophages engulfing myelin debris. These results indicate that Dst is important for normal PNS myelin organization and Dst disruption in Schwann cells induces late-onset neuropathy and sensory ataxia. MAIN POINTS: Dystonin (Dst) disruption in Schwann cells results in late-onset neuropathy and sensory ataxia. Dst in Schwann cells is important for normal myelin organization in the peripheral nervous system.

The use of BIOCHIP mosaics in diagnostics of bullous pemphigoid: Evaluation and comparison to conventional multistep procedures.

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering disease associated with autoantibodies against BP180 and/or BP230 antigens. The immunoassays available for serological diagnostics include indirect immunofluorescence (IIF) on monkey esophagus (ME), salt-split skin (SSS), and enzyme-linked immunosorbent assay (ELISA) for BP180-NC16a and BP230. Only a few studies validated innovative BIOCHIP mosaic, but none compared agreement between BIOCHIP substrates with conventional methods separately. METHODS: We evaluated the agreement between BIOCHIP and conventional methods and assessed sensitivity and specificity in BP diagnosis. The study comprised 51 BP patients and 39 controls. RESULTS: Analysis showed very good agreement between BIOCHIP-SSS vs classic IIF-SSS (0.933, P < 0.001) and for BIOCHIP-BP180-NC16a vs ELISA-BP180-NC16a (0.933, P < 0.001). A good strength of agreement between BIOCHIP-ME vs classic IIF-ME was observed (0.694, P < 0.001) similar to BIOCHIP-BP230 vs ELISA-BP230 (0.793, P < 0.001). BIOCHIP-ME sensitivity was 51.0%, whereas IIF-ME was 76.5%. Epidermal reaction on BIOCHIP-SSS was found in 94.1% of BP patients and in all patients on IIF-SSS (sensitivity 100%). BIOCHIP-BP180-NC16a sensitivity was lower than in ELISA-BP180-NC16a (76.5% vs 82.4%). BP230 sensitivity of both methods was similar (45.1% vs 43.1%). The specificity for all antigens was 100%. CONCLUSION: BIOCHIP mosaic is a useful method presenting satisfactory agreement with conventional immunoassays.

Autoantibody Profile of a Cohort of 54 Italian Patients with Linear IgA Bullous Dermatosis: LAD-1 Denoted as a Major Auto-antigen of the Lamina Lucida Subtype.

Linear IgA bullous dermatosis (LABD) is characterized by presence of multiple IgA autoantibodies, and a comparatively lesser number of IgG antibodies, directed against different hemidesmosomal antigens. The main autoantigens are LAD-1, LABD-97, BP180 and BP230, type VII collagen and laminin 332. We retrospectively studied the serology of 54 Italian patients with LABD using enzyme-linked immunosorbent assay (ELISA), immunoblotting assay, and indirect immunofluorescence on monkey oesophagus and salt-split skin. Among these, indirect immunofluorescence of salt-split skin elicits the greatest sensitivity. Sixty-three percent of the sera were observed to be positive, with a lamina lucida pattern observed in 48%, a sub-lamina densa pattern in 2% and a mixed pattern in 13% of the cases. IgA reactivity to LAD-1 on immunoblotting was found in 52% of sera, to BP180-NC16A by ELISA in 32% and to BP230 in 26%. Only 17% of patients possessed circulating IgG autoantibodies. LAD-1 was determined to be a major autoantigen of the lamina lucida subtype. Combined serological assays demonstrated a high sensitivity (82%), suggesting that this approach could support diagnosis when a biopsy is not feasible or direct immunofluorescence results are negative.

BPAG1 in muscles: Structure and function in skeletal, cardiac and smooth muscle.

BPAG1, also known as Dystonin or BP230, belongs to the plakin family of proteins, which has multiple cytoskeleton-binding domains. Several BPAG1 isoforms are produced by a single BPAG1 genomic locus using different promoters and exons. For example, BPAG1a, BPAG1b, and BPAG1e are predominantly expressed in the nervous system, muscle, and skin, respectively. Among BPAG1 isoforms, BPAG1e is well studied because it was first identified as an autoantigen in patients with bullous pemphigoid, an autoimmune skin disease. BPAG1e is a component of hemidesmosomes, the adhesion complexes that promote dermal-epidermal cohesion. In the nervous system, the role of BPAG1a is also well studied because disruption of BPAG1a results in a phenotype identical to that of Dystonia musculorum (dt) mutants, which show progressive motor disorder. However, the expression and function of BPAG1 in muscles is not well studied. The aim of this review is to provide an overview of and highlight some recent findings on the expression and function of BPAG1 in muscles, which can assist future studies designed to delineate the role and regulation of BPAG1 in the dt mouse phenotype and in human hereditary sensory and autonomic neuropathy type 6 (HSAN6).

Regulatory T-cell dysfunction induces autoantibodies to bullous pemphigoid antigens in mice and human subjects.

BACKGROUND: Regulatory T (Treg) cells play a crucial role in peripheral immune tolerance in multiple organs, including the skin. Thus far, the effect of peripheral immune tolerance failure on autoantibody-related autoimmune reactions to the skin is unclear. OBJECTIVE: We sought to elucidate the target autoantigens in the skin under the condition of Treg cell dysfunction caused by forkhead box P3 (Foxp3) gene mutations in scurfy mice and patients with immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. METHODS: Sera and skin from scurfy mice and sera from patients with IPEX syndrome were analyzed to detect target autoantigens by using immunofluorescence studies, ELISAs, and immunoblotting. The pathogenicity of scurfy IgG was examined by using a passive transfer experiment. CD4+ T cells from scurfy mice were transferred to immunodeficient mice to examine their pathogenicity. Signal transducer and activator of transcription 6 (Stat6)-/- scurfy mice were analyzed to further clarify the molecular pathway of autoantibody production. Follicular helper T-cell counts are measured in Stat6-/- scurfy mice and scurfy mice. RESULTS: Scurfy mice spontaneously generated IgG autoantibodies to the dermal-epidermal junction, which had been class-switched from IgM within 12 days after birth. The target autoantigens were murine BP230 and type XVII collagen (COL17). The scurfy polyclonal autoantibodies did not induce skin fragility in neonatal mice. Autoantibody production was induced by CD4+ T cells from scurfy mice and was ameliorated by Stat6 gene knockout in association with a decrease of follicular helper T cells. We also identified autoantibodies to COL17 and BP230 in patients with IPEX syndrome and found an association between production of autoantibodies to COL17 and an eczematous skin phenotype. CONCLUSIONS: Dysregulation of Treg cells generates autoantibodies to COL17 and BP230 in vivo.

One gene but different proteins and diseases: the complexity of dystonin and bullous pemphigoid antigen 1.

Since the immunochemical identification of the bullous pemphigoid antigen 230 (BP230) as one of the major target autoantigens of bullous pemphigoid (BP) in 1981, our understanding of this protein has significantly increased. Cloning of its gene, development and characterization of animal models with engineered gene mutations or spontaneous mouse mutations have revealed an unexpected complexity of the gene encoding BP230. The latter, now called dystonin (DST), is composed of at least 100 exons and gives rise to three major isoforms, an epithelial, a neuronal and a muscular isoform, named BPAG1e (corresponding to the original BP230), BPAG1a and BPAG1b, respectively. The various BPAG1 isoforms play a key role in fundamental processes, such as cell adhesion, cytoskeleton organization, and cell migration. Genetic defects of BPAG1 isoforms are the culprits of epidermolysis bullosa and complex, devastating neurological diseases. In this review, we summarize recent advances of our knowledge about several BPAG1 isoforms, their role in various biological processes and in human 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.

A case of pemphigoid gestationis with concurrent IgG antibodies to BP180, BP230 and type VII collagen.

A 22-year-old primigravida had a pruritic, erythematous, bullous eruption on the skin during the 26th week of gestation. After delivery the eruption flared up. The diagnosis of pemphigoid gestationis was confirmed based on histopathological and immunofluorescence findings. The result of immunoblotting showed IgG autoantibodies which reacted against BP230 in epidermal extracts and 290 kDa type VII collagen in dermal extracts. The BP180 antibodies were also detected by an enzyme-linked immunosorbent assay BP180NC16a diagnosis kit. Pulsed corticosteroid and cyclophosphamide resulted in a favourable response at the acute stage. The patient was cured in 2 years. The analysis of the patient's autoantibodies provides strong evidence for the involvement of epitope spreading in her autoimmune disease.

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.

Roles of dystonin isoforms in the maintenance of neural, muscle, and cutaneous tissues.

Dystonin (DST), also known as bullous pemphigoid antigen 1 (BPAG1), encodes cytoskeletal linker proteins belonging to the plakin family. The DST gene produces several isoforms, including DST-a, DST-b, and DST-e, which are expressed in neural, muscle, and cutaneous tissues, respectively. Pathogenic DST mutations cause hereditary sensory and autonomic neuropathy type 6 (HSAN-VI) and epidermolysis bullosa simplex (EBS); therefore, it is important to elucidate the roles of DST isoforms in multiple organs. Recently, we have used several Dst mutant mouse strains, in which the expression of Dst isoforms is disrupted in distinct patterns, to gain new insight into how DST functions in multiple tissues. This review provides an overview of the roles played by tissue-specific DST isoforms in neural, muscle, and cutaneous tissues.

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.

Bullous pemphigoid (BP) patients with selective IgG autoreactivity against BP230: Review of a rare but valuable cohort with impact on the comprehension of the pathogenesis of BP.

Bullous pemphigoid (BP) is the most common autoimmune blistering disease. BP is characterized by the development of tense blisters induced by tissue-bound specific autoantibodies directed against the major autoantigens bullous pemphigoid autoantigen 180 (BP180, also called BPAG2 or Collagen XVII) and bullous pemphigoid autoantigen 230 (BP230, also called BPAG1 or dystonin). The vast majority of BP patients have autoantibodies targeting BP180, or both, BP180 and BP230. The hemidesmosomal protein BP180 is regarded as the main autoantigen, whereas the pathophysiologic relevance of intracellularly-located BP230 is controversial. A small subpopulation of BP patients selectively reveals autoantibodies against BP230 (BP230+ patients) strongly supporting that BP230 autoantibodies might be sufficient to induce skin pathology. In line, BP animal models have been developed, which successfully mimic a human BP phenotype by targeting BP230. In this context, our group has recently shown that a murine autoantibody targeting BP230 induces subepidermal blisters in vivo. This finding suggests that blister formation in the population of patients with selective autoreactivity against BP230 may share pathophysiologic features of pathogenic anti-BP230 autoantibodies in our murine model. This review summarizes the clinical features of BP patients with selective autoreactivity against BP230, enlightens the currently available BP mouse models targeting BP230 and discusses the potential pathophysiological mechanism of BP230 autoantibodies.