Association of Bullous Pemphigoid With Dipeptidyl-Peptidase 4 Inhibitors in Patients With Diabetes: Estimating the Risk of the New Agents and Characterizing the Patients

Skin-Related Adverse Reactions Induced by Oral Antidiabetic Drugs-A Review of Literature and Case Reports

Type 2 diabetes (T2DM) is a chronic metabolic disease with a steadily increasing prevalence worldwide. Diabetes affects the function of many organs, including the skin. Pharmacotherapy for T2DM is mainly based on oral hypoglycemic drugs. The therapeutic strategy is chosen taking into account the individual patient's characteristics, among other comorbidities. Antidiabetic drugs can induce cutaneous adverse reactions (CADRs) ranging in severity from mild erythema to serious disorders such as DRESS or Stevens-Johnson syndrome. CADRs can result from hypersensitivity to the drug but can also be related to the mechanism of action of the drug or cross-reactivity with drugs of similar structure. This paper reviews CADRs induced by oral antidiabetic drugs, considering their dermatological manifestations and possible pathomechanisms. Particular attention was paid to specific dermatological conditions such as dipeptidylpeptidase 4 inhibitor-associated bullous pemphigoid or Fournier's gangrene associated with sodium-glucose cotransporter 2 inhibitor therapy. Knowledge of the dermatological manifestations of CADRs is important in clinical practice. Recognition of a skin lesion resulting from an adverse drug reaction allows for appropriate management, which in this case is primarily related to drug discontinuation. This is particularly important in the treatment of T2DM since this disease has a high prevalence in the elderly, who are at higher risk of adverse drug reactions.

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.

Dermatological side effects of dipeptidyl Peptidase-4 inhibitors in diabetes management: a comprehensive review

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of drugs that enhance the incretin-insulin pathway and offer effective glycemic control in type 2 diabetes mellitus. However, these drugs may be associated with various dermatological side effects, ranging from mild to severe. This review article summarizes the current literature on the dermatological side effects of DPP-4 inhibitors, including bullous pemphigoid, severe cutaneous adverse drug reactions, fixed drug eruptions, and other mucocutaneous reactions. The review also discusses the possible mechanisms, risk factors, diagnosis, and management of these side effects. This review aims to increase the awareness and vigilance of healthcare providers in recognizing and managing the dermatological side effects of DPP-4 inhibitors and to emphasize the need for further research and surveillance to optimize diabetes care and patient safety.

An Urticarial and Acral Manifestation of Bullous Pemphigoid After Vildagliptin Therapy: A Case Report

Drug-induced bullous pemphigoid (DBP) may present identical to an idiopathic type of illness. Thus, DBP should be considered as a differential diagnosis when evaluating the cause of bullous pemphigoid (BP) in elderly individuals with diabetes. We present the case of a 65-year-old "young-elderly" female who developed bullous lesions after initiation of medication. This case report casts light on a commonly prescribed antidiabetic drug, a dipeptidyl peptidase-4 inhibitor, vildagliptin, and its unforeseen complication in the elderly. The long-term complication is BP. With long-term use, there is an increased likelihood of encountering such cases among the elderly. Thus, we recommend that DBP be considered an important early differential diagnosis among elderly diabetics presenting with initial signs and symptoms of BP.

Proteomic changes related to actin cytoskeleton function in the skin of vildagliptin-treated mice

BACKGROUND

Vildagliptin, a dipeptidyl peptidase-4 inhibitor (DPP-4i) is a widely used type 2 diabetes medication that is associated with an up-to 10-fold increased risk for the development of bullous pemphigoid (BP), an autoimmune skin disease. The mechanism by which vildagliptin promotes the development of BP remains unknown.

OBJECTIVE

To elucidate effects of vildagliptin treatment on the mouse cutaneous proteome.

METHODS

We analyzed the cutaneous proteome of nondiabetic mice treated for 12 weeks with vildagliptin using label-free shotgun mass spectrometry (MS), two-dimensional difference gel electrophoresis (2D-DIGE), immunohistochemistry, immunoblotting, and quantitative real-time polymerase chain reaction.

RESULTS

Although vildagliptin treatment did not cause any clinical signs or histological changes in the skin, separate MS and 2D-DIGE analyses revealed altered cutaneous expression of several proteins, many of which were related to actin cytoskeleton remodeling. Altogether 18 proteins were increased and 40 were decreased in the vildagliptin-treated mouse skin. Both methods revealed increased levels of beta-actin and C->U-editing enzyme APOBEC2 in vildagliptin-treated mice. However, elevated levels of a specific moesin variant in vildagliptin-treated animals were only detected with 2D-DIGE. Immunohistochemical staining showed altered cutaneous expression of DPP-4, moesin, and galectin-1. The changed proteins detected by MS and 2D-DIGE were linked to actin cytoskeleton remodeling, transport, cell movement and organelle assembly.

CONCLUSION

Vildagliptin treatment alters the cutaneous proteome of nondiabetic mice even without clinical signs in the skin. Cytoskeletal changes in the presence of other triggering factors may provoke a break of immune tolerance and further promote the development of BP.

Ocular cicatricial pemphigoid following Dipeptidyl Peptidase-4 inhibitor use: A case report

Purpose

To report a rare Ocular Cicatricial Pemphigoid (OCP) case in a patient taking a Dipeptidyl Peptidase-4 Inhibitor (DPP-4 inhibitor), a medication used for the management of type 2 diabetes, for at least six years.

Observations

A 64-year-old male presented with refractory bilateral conjunctival inflammation and ocular discharge that had persisted for two months, despite multiple prior therapies for presumed bacterial conjunctivitis. Upon initial examination, clinical findings strongly suggested OCP, and he had elevated levels of anti-BP180 antibodies. Despite receiving systemic treatments such as steroid pulse therapy and therapeutic plasma exchange after discontinuing DPP-4 inhibitors, his condition progressively worsened, with manifestations such as forniceal shortening in his left eye. Consequently, the patient required keratoepithelioplasty, amniotic membrane transplantation in his left eye, and bilateral eyelid entropion surgery. His condition initially worsened for a time after discontinuing the DPP-4 inhibitor, but it gradually improved over time, and ocular surface surgical intervention was not required in the right eye.

Conclusions and Importance

The findings in this study demonstrate that severe refractory OCP may occur while taking the DPP-4 inhibitor, thus indicating that a detailed interview regarding medications is essential for patients with ocular pemphigoid, especially those with type 2 diabetes.

Accurate diagnosis of bullous pemphigoid requires multiple health care visits

Introduction

Accurate use of diagnostic codes is crucial for epidemiological and genetic research based on electronic health record (EHR) data.

Methods

This retrospective study validated the International Classification of Diseases (ICD)-10 diagnostic code L12.0 for bullous pemphigoid (BP) using EHR data from two Finnish university hospitals. We found 1225 subjects with at least one EHR entry of L12.0 between 2009 and 2019. BP diagnosis was based on clinical findings characteristic of BP and positive findings on direct immunofluorescence (DIF), BP180-NC16A enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence (IIF) assay.

Results

True BP was found in 901 patients; the positive predictive value (PPV) for L12.0 was 73.6% (95% CI 71.0-76.0). L12.0 was more accurately registered in dermatology units than any specialized health care units (p<0.001). Including patients with multiple L12.0 registrations (≥3), increased the accuracy of the L12.0 code in both dermatology units and other settings.

Discussion

One diagnostic code of L12.0 is not enough to recognize BP in a large epidemiological data set; including only L12.0 registered in dermatology units and excluding cases with <3 L12.0 record entries markedly increases the PPV of BP diagnosis.

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.

The effect of dipeptidyl peptidase-4 inhibitor on incidence and clinical course in bullous pemphigoid patients in a tertiary medical center

Several studies have reported an association between dipeptidyl peptidase 4 inhibitor (DPP4i), a commonly prescribed second-line oral antihyperglycemic drug, and bullous pemphigoid (BP). However, the benefits of DPP4i withdrawal in patients with BP remain controversial. This study primarily aimed to evaluate the clinical severity of DPP4i-associated BP by comparing it to those without Type 2 diabetes mellitus (DM). The secondary objective was to determine whether cessation of DPP4i is necessary for all patients with BP. This retrospective case-control study included 83 patients. The participants were divided into three groups according to their diabetic status and the status of discontinuance or continuance of DPP4i. The 12-month follow-up of the monthly dosage of systemic steroids per body weight (kg) and the percentage of systemic steroid off-therapy in these participants were recorded since the diagnosis of BP. Compared to patients with BP without DM, the 1st, 3rd, and 12th systemic prednisolone doses were significantly lower in the DPP4i group (p = 0.01684, 0.02559, and 0.009336, respectively). The 12th systemic prednisolone dose was significantly lower in patients who discontinued DPP4i (p = 0.0338). Nevertheless, several spontaneous remissions with systemic steroid off-therapy were also noted in the DPP4i-continuance group within 12 months of follow-up. This article supports the favorable impact of DPP4i withdrawal in patients with BP and shows that DPP4i may incite or aggravate BP, resulting in a milder disease course.

Targeting type 2 inflammation in bullous pemphigoid: current and emerging therapeutic approaches

Bullous pemphigoid (BP) is one of the most common autoimmune bullous diseases and mainly affects an elderly population with multi-morbidity. Due to the frailty of many BP patients, existing treatment options are limited. The blisters associated with BP result from IgG and IgE autoantibodies binding to the central components of hemidesmosome, BP180, and BP230, stimulating a destructive inflammatory process. The known characteristic features of BP, such as intense pruritus, urticarial prodrome, peripheral eosinophilia, elevated IgE, as well as recent expanding evidence from in vitro and in vivo studies implicate type 2 inflammation as an important driver of BP pathogenesis. Type 2 inflammation is an inflammatory pathway involving a subset of CD4+ T cells that secrete IL-4, IL-5, and IL-13, IgE-secreting B cells, and granulocytes, such as eosinophils, mast cells, and basophils. It is believed that effectors in type 2 inflammation may serve as novel and effective treatment targets for BP. This review focuses on recent understandings of BP pathogenesis with a particular emphasis on the role of type 2 inflammation. We summarize current clinical evidence of using rituximab (B-cell depletion), omalizumab (anti-IgE antibody), and dupilumab (anti-IL-4/13 antibody) in the treatment of BP. The latest advances in emerging targeted therapeutic approaches for BP treatment are also discussed.

Bullous Pemphigoid Associated With Dipeptidyl Peptidase-4 Inhibitors: A Case Report and Review of Current Evidence

Dipeptidyl peptidase-4 inhibitors (DPP-4i), or gliptins, are a widely used glucose-lowering agents. A growing amount of evidence pointed to a possible role of DPP-4i in the induction of bullous pemphigoid (BP), which is an auto-immune skin blistering disease that mainly affects the elderly. In this article we discuss a case of DPP-4i associated BP and we provide an updated review of the current knowledge regarding this emerging entity. Use of DPP-4i, particularly vildagliptin, was found to significantly increase the risk of BP. BP180 would be in the center of the aberrant immune response. DPP-4i induced BP is thought to be associated with male gender, mucosal involvement, and milder inflammatory phenotype especially in Asian population. Generally, patients may not remit fully after DPP-4i withdrawal only and require either topical or systemic glucocorticoid courses.

Bullous pemphigoid and dipeptidyl peptidase-4 inhibitors: evaluation of clinical course and treatment response

BACKGROUND

Dipeptidyl peptidase-4 inhibitors (DPP4is), drugs used to treat type 2 diabetes mellitus (DM2), show a significant association with bullous pemphigoid (BP) development.

OBJECTIVES

To evaluate the clinical course and development of BP among patients with DM2 treated with DPP4is.

METHODS

This retrospective cohort study included all the patients with BP and comorbid DM2 who visited Sheba Medical Center during 2015-2020.

RESULTS

Among 338 patients with BP, 153 were included in our study. In 92 patients, BP diagnosis was attributed to the use of DPP4is. The patients with DPP4i-associated BP had fewer neurological and cardiovascular comorbidities and higher blistered body surface area (BSA) at first presentation, with noticeable upper and lower limb involvement. These patients were younger and more responsive to treatment, with a greater reduction in their BSA score after 2 months of treatment.

CONCLUSIONS

The clinical features of patients with BP treated with DPP4is were initially more severe; however, during follow-up, a marked clinical improvement was noticed, especially among patients who had ceased the drug. Therefore, although withdrawal of the drug may not impose disease remission, it can alleviate the disease course and avert the need for treatment escalation.

Comorbidity in bullous pemphigoid: up-date and clinical implications

Bullous pemphigoid is the most common autoimmune blistering disease in industrialized countries and particularly affects the elderly. In this patient population, comorbid diseases are frequent and may complicate management and treatment of bullous pemphigoid. A better understanding why distinct diseases are more frequent in bullous pemphigoid patients may lead to new pathophysiological insights and - as a consequence - result in better patient care. The association of bullous pemphigoid with neurological and psychiatric diseases is well known and confirmed by several case-control studies. Association with further diseases such as malignancy and metabolic diseases are still discussed controversially. In recent years new relationships between bullous pemphigoid and autoimmune as well as inflammatory skin diseases have been reported. This review provides a systematic overview on studies addressing comorbidity in bullous pemphigoid patients. Increasing the awareness of both, common and rare comorbid diseases, may enable clinicians to optimize patient support and individualized treatment of bullous pemphigoid.

Researching trends in pemphigoid diseases: A bibliometric study of the top 100 most cited publications

Background

In the field of autoimmune and inflammatory disorders, different approaches were applied to provide information regarding disease activity, comorbidities, epidemiological reports and risk factors. However, no previous studies had thoroughly analyzed the research trend in the field, and the bibliometric analysis focusing on pemphigoid diseases was available. The objective of the current study was to evaluate the current research trend in the field.

Methods

A search has been conducted for the Web of Science database based on various subcategories of pemphigoid diseases. Detailed information including articles' publication types, Author information, citation, and publication information was attained for further analysis.

Results

Within the 6,995 studies, the top 100 most-cited articles were extracted for analysis. Among the top 100 studies, 70% of the studies focused on bullous pemphigoid. More than 60% of the top 100 studies were studies with original data. Furthermore, 30% of the studies were guidelines and narrative reviews. For the issues primarily focused on, most of the high-impact studies described the molecular mechanism of pemphigoid diseases (26%), managements (19%), risk factors of pemphigoid diseases (17%). Additionally, some other studies provided general review or discussed about the issue of epidemiology, diagnosis/definition, comorbidities and clinical characteristics of pemphigoid diseases.

Conclusion

This comprehensive bibliographic study of pemphigoid diseases provided an overview of current research focuses in the field. Topics such as disease management, molecular mechanism of pathogenesis, and drug-inducing pemphigoid diseases were highly mentioned in the most-cited studies. For researchers and clinicians, the researching trend and study focus in the top-100 cited studies could serve as a potential reference for future investigation and patient management.

Dipeptidyl Peptidase 4 Inhibitor‒Associated Bullous Pemphigoid Is Characterized by an Altered Expression of Cytokines in the Skin

Dipeptidyl peptidase 4 inhibitors (DPP4is), commonly used drugs for treatment of type 2 diabetes, increase the risk for bullous pemphigoid (BP). Currently, the mechanism leading to the loss of immunological tolerance of the cutaneous adhesion molecule BP180 as well as similarities and differences in disease progression between DPP4i-associated BP (DPP4i-BP) and DPP4i-independent regular BP are largely unknown. We analyzed the expression of 32 cytokines and two proteases by Luminex and ELISA assays in samples taken from lesional and nonlesional skin of patients with regular BP or DPP4i-BP and healthy controls. Cytokines mediating B-cell survival and targeting such as BAFF, CCL4, CXCL12, and IL-6 were expressed at a higher level in the lesional regular BP skin than the levels in the lesional DPP4i-BP skin. The DPP4i-BP samples had increased levels of eosinophilic cytokines CCL1, CCL17, CCL26, and IL-5, which correlated with the serum level of anti-BP180 NC16A IgG autoantibodies. The mRNA expression of BAFF, IL6, CCL1, CCL17, CCL26, and IL5 measured by qPCR correlated with the protein levels. Taken together, the cutaneous cytokine profiles were found to provide distinctive molecular fingerprints between regular BP and DPP4i-BP.

Dipeptidyl-peptidase IV inhibitor (DPP4i) confers increased odds of bullous pemphigoid even years after drug initiation

The timing pattern in which dipeptidyl-peptidase IV inhibitors (DPP4i) confer the risk of bullous pemphigoid (BP) is unknown. To investigate the odds of BP following exposure to DPP4i and to perform a duration-response analysis evaluating the risk of BP in relation to the duration of exposure to the culprit drug. A population-based nested case-control study was performed comparing diabetic patients with BP (n = 1458) with age-, sex- and ethnicity-matched diabetic control subjects (n = 6051) with respect to the prevalence of exposure to DPP4i. Adjusted odds ratios (ORs) were estimated by logistic regression. Overall exposure to DPP4i was associated with an 80% increase in the odds of subsequent BP (OR, 1.81; 95% CI, 1.46-2.08; P < 0.001). In an intraclass analysis, the odds of BP were increased in association with vildagliptin (OR, 3.40; 95% CI, 2.69-4.29; P < 0.001) and sitagliptin (OR, 1.56; 95% CI, 1.33-1.84; P < 0.001). In a duration-response analysis, the highest likelihood of BP was found 1-2 years after commencing the drug (OR, 2.66; 95% CI, 1.97-3.59; P < 0.001). The odds of BP were increased across all time periods and retained its statistical significance even ≥ 6 years after the drug initiation (OR, 1.44; 95% CI, 1.09-1.91; P = 0.011). Relative to other diabetic patients with BP, patients with DPP4i-associated BP were more likely to be admitted to inpatient dermatologic wards (OR, 1.66; 95% CI, 1.30-2.13; P < 0.001) and had higher mean(SD) numbers of outpatient dermatologist visits (14.7[14.8] vs. 12.3[13.2], respectively; P = 0.006). DPP4i should be suspected as a predisposing factor for BP even numerous years after the drug initiation.

Dipeptidyl Peptidase-4 Inhibitor-Related Bullous Pemphigoid: Clinical, Laboratory, and Histological Features, and Possible Pathogenesis

Dipeptidyl peptidase-4 inhibitor (DPP4i) is a widely used antidiabetic agent. Emerging cases of DPP4i-associated bullous pemphigoid (DBP), whose pathogenesis remains unclear, have been reported. Thus, a retrospective study was conducted from January 2016 to June 2021 to determine the clinical, laboratory, and histopathological features of DBP and idiopathic bullous pemphigoid (IBP). We set up in vitro experiments using vildagliptin-treated HaCaT keratinocytes to validate what we found by analyzing published RNA sequencing data about the genes related to the dermal-epidermal junction. We also observed IL-6 expression by HaCaT cells treated with vildagliptin. We enrolled 20 patients with DBP and 40 patients with IBP. The total Bullous Pemphigoid Disease Area Index (BPDAI) score was similar in both groups. However, the BPDAI score of erosions and blisters in DBP was significantly higher than that in IBP (24.6 vs. 16.68, p = 0.0189), and the score for urticaria and erythema was lower in DBP (12 vs. 19.05, p = 0.0183). The pathological features showed that the mean infiltrating eosinophil number per high-power field was significantly lower in DBP than in IBP (16.7 vs. 27.08, p = 0.023). The expression of LAMA3, LAMB3, LAMC2, DST, and COL17A1 decreased significantly in vildagliptin-treated human keratinocytes. On the other hand, IL-6, the hallmark cytokine of bullous pemphigoid (BP) severity, was found to be upregulated in HaCaT cells by vildagliptin. These experimental findings imply less of a requirement for eosinophil infiltration to drive the inflammatory cascades in DBP blistering. Both immunologic and non-immunologic pathways could be employed for the development of DBP. Our findings may help explain the higher incidence of non-inflammatory BP that was observed in DBP.

Type XVII collagen: Relevance of distinct epitopes, complement-independent effects, and association with neurological disorders in pemphigoid disorders

Pemphigoid diseases (PD) are autoimmune skin blistering diseases characterized by autoantibodies directed against proteins of the cutaneous basement membrane zone (BMZ). One of the major antigens is type XVII collagen (BP180), a transmembrane glycoprotein, which is targeted in four PDs: bullous pemphigoid, mucous membrane pemphigoid, linear IgA dermatosis, and pemphigoid gestationis. To date, different epitopes on BP180 have been described to be recognized by PD disease patients’ autoantibodies. Different BP180 epitopes were associated with distinct clinical phenotypes while the underlying mechanisms are not yet fully understood. So far, the main effects of anti-BP180 reactivity are mediated by Fcγ-receptors on immune cells. More precisely, the autoantibody–antigen interaction leads to activation of complement at the BMZ and infiltration of immune cells into the upper dermis and, by the release of specific enzymes and reactive oxygen species, to the degradation of BP180 and other BMZ components, finally manifesting as blisters and erosions. On the other hand, inflammatory responses independent of Fcγ-receptors have also been reported, including the release of proinflammatory cytokines and internalization and depletion of BP180. Autoantibodies against BP180 can also be found in patients with neurological diseases. The assumption that the clinical expression of PD depends on epitope specificity in addition to target antigens, autoantibody isotypes, and antibody glycosylation is supported by the observation that epitopes of PD patients differ from those of PD patients. The aim of the present review is to describe the fine specificities of anti-BP180 autoantibodies in different PDs and highlight the associated clinical differences. Furthermore, the direct effects after binding of the autoantibodies to their target are summarized.

The significance of preclinical anti-BP180 autoantibodies

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease. Although the pathomechanism of BP onset has yet to be elucidated in detail, BP autoantibodies targeting two hemidesmosomal components, BP180 and BP230, are known to play a pivotal role in BP pathogenesis. Thus, the detection and measurement of BP autoantibodies are necessary for diagnosing BP and monitoring the disease activity. Immune assays such as immunofluorescence microscopy, immunoblotting, and ELISAs using BP180 and BP230 detect BP autoantibodies in most BP cases with high specificity; however, BP autoantibodies are sometimes detected in BP patients before the onset of this disease. BP autoantibodies that are detected in patients without typical tense blisters are defined as “preclinical BP autoantibodies”. These preclinical BP autoantibodies are detected even in a low percentage of normal healthy individuals. Although the importance of preclinical BP autoantibodies remains elusive, these autoantibodies might be a potential risk factor for subsequent BP development. Therefore, previous comparative epidemiological studies have focused on the prevalence of preclinical BP autoantibodies in populations susceptible to BP (e.g., the elderly) or in diseases with a higher risk of comorbid BP. This mini-review summarizes the literature on the prevalence of preclinical BP autoantibodies in patients with various conditions and diseases, and we discuss the significance of preclinical BP autoantibody detection.

Use of gliptins reduces levels of SDF-1/CXCL12 in bullous pemphigoid and type 2 diabetes, but does not increase autoantibodies against BP180 in diabetic patients

The use of dipeptidyl peptidase 4 (DPP4) inhibitors, (also known as gliptins), is associated with an increased risk of bullous pemphigoid (BP), an autoimmune blistering skin disease. To explore the mechanism behind gliptin-associated BP we investigated circulating autoantibodies against the major BP autoantigen BP180 in serum samples from patients with type 2 diabetes (T2D) with preceding gliptin medication (n = 136) or without (n = 136). Sitagliptin was the most frequently prescribed gliptin (125/136 patients). Using an ELISA assay, we showed that IgG autoantibodies against the immunodominant NC16A domain of BP180 were found in 5.9% of gliptin treated and in 6.6% of non-gliptin treated T2D patients. We found that 28% of gliptin treated patients had IgG autoantibodies recognizing the native full-length BP180 in ELISA, but among non-gliptin treated the seropositivity was even higher, at 32%. Further ELISA analysis of additional serum samples (n = 57) found no major changes in the seropositivity against BP180 during a follow-up period of about nine years. In immunoblotting, full-length BP180 was recognized by 71% of gliptin treated and 89% of non-gliptin treated T2D patients, but only by 46% of the age-and sex-matched controls. The chemokine stromal derived factor-1(SDF-1/CXCL12) is one of the major substrates of DPP4. Immunostainings showed that the expression of SDF-1 was markedly increased in the skin of BP patients, but not affected by prior gliptin treatment. We found that the use of gliptins decreased the serum level of SDF-1α in both BP and T2D patients. Our results indicate that the autoantibodies against the linear full-length BP180 are common in patients with T2D, but seropositivity is unaffected by the use of sitagliptin.

Bullous pemphigoid in India: Review of cases registered in an autoimmune bullous disease clinic

Background

Information on bullous pemphigoid in an Indian context is scarce.

Aim

To report clinico-demographic profile, associated comorbidities and prescription pattern of bullous pemphigoid patients in India.

Methods

This was a retrospective study, where past records of all bullous pemphigoid patients diagnosed and treated between November 2013 and October 2019 were accessed and analysed. Patients having a compatible clinical presentation with either histopathological and/or direct immunofluorescence evidence of bullous pemphigoid were included.

Results

There were 96 bullous pemphigoid patients, with a male: female ratio of 1.6:1. The mean age at diagnosis was 62.5 ± 2.2 years, with mean duration of illness 27.5 ± 4.5 months before presentation. Comorbidities were present in 80 (83%) patients, with type 2 diabetes mellitus (38.5%), hypertension (36.4%) and neurological illness (16.7%) being the commonest ones. Clinically, blisters were the predominant presentation in 81 (84.4%) patients. The majority (87.5%) of patients showed a predominant eosinophilic infiltrate on histopathology. Direct immunofluorescence revealed immunoglobulin G deposits with complement C3 in 77 (80.2%) cases. The majority of patients (77.1%) were treated with oral prednisolone, either alone (11.5%) or in combination (65.6%) with other topical and systemic agents. Topical steroids were used in 29.1%, azathioprine in 28%, dapsone in 16.7% and omalizumab in 6.2% of patients.

Limitations

The study is retrospective. Immunofluorescence on salt split skin, direct immunofluorescence serration pattern analysis, and immunoblotting were not performed. Hence, there is a possibility that a few included cases were suffering from other subepidermal autoimmune bullous diseases like epidermolysis bullosa acquisita or anti-p200 pemphigoid.

Conclusion

Bullous pemphigoid patients in this study had a younger age of onset and showed male preponderance. Comorbidities like type 2 diabetes, hypertension and neurological disorders were frequent. Cutaneous blisters were the most frequent clinical presentation. Systemic corticosteroids comprised the mainstay of therapy.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Clinical features of dipeptidyl peptidase-4 inhibitor-associated bullous pemphigoid in Japan: A nationwide retrospective observational study

Many cases of bullous pemphigoid (BP) have been reported in patients taking dipeptidyl peptidase-4 inhibitors (DPP-4i), which are the most widely used antidiabetic drug for type 2 diabetes mellitus. However, no large-scale survey has been conducted in Japan. This retrospective study investigated the incidence, clinical presentation, and clinical course of DPP-4i-associated BP (DPP-4i-BP) using epidemiological data from a nationwide registry for BP. In 2016, 713 new BP patients at 94 dermatological institutes were registered, 243 (34.1%) with DPP-4i-BP and 461 (64.7%) with non-DPP-4i-BP. The male-to-female ratio was 1.9 and 0.84, respectively. Patients with DPP-4i-BP were predominantly male. Non-inflammatory BP was more common in DPP-4i-BP (33.3%) than in non-DPP-4i-BP (14.6%), while inflammatory BP was common in both. No specific subtype or difference in disease severity was evident in DPP-4i-BP. The most common gliptins administered to DPP-4i-BP patients were vildagliptin (37.2%) and linagliptin (23.8%). DPP-4i intake was discontinued in 79.9% of cases after diagnosis. Some DPP-4i-BP patients (17.6%) achieved spontaneous remission after discontinuing DPP-4i without requiring the use of systemic corticosteroids and/or adjuvant therapy. Mean duration to achieve disease control was 2.87 months. The odds ratio for non-inflammatory BP requiring systemic corticosteroids and/or adjuvant therapy was low (0.52), suggesting that remission was achieved easily with supportive care in that phenotype. Non-inflammatory and mild cases of DPP-4i-BP may resolve spontaneously with supportive care, including the discontinuation of DPP-4i and no oral corticosteroid therapy.

Emerging Role of Dipeptidyl Peptidase-4 in Autoimmune Disease

Dipeptidyl-peptidase IV (DPP4), originally identified as an aminopeptidase in 1960s, is an ubiquitously expressed protease presented as either a membrane-bound or soluble form. DPP4 cleaves dipeptide off from the N-terminal of its substrates, altering the bioactivity of its substrates. Subsequent studies reveal that DPP4 is also involved in various cellular processes by directly binding to a number of ligands, including adenosine deaminase, CD45, fibronectin, plasminogen, and caveolin-1. In recent years, many novel functions of DPP4, such as promoting fibrosis and mediating virus entry, have been discovered. Due to its implication in fibrotic response and immunoregulation, increasing studies are focusing on the potential role of DPP4 in inflammatory disorders. As a moonlighting protein, DPP4 possesses multiple functions in different types of cells, including both enzymatic and non-enzymatic functions. However, most of the review articles on the role of DPP4 in autoimmune disease were focused on the association between DPP4 enzymatic inhibitors and the risk of autoimmune disease. An updated comprehensive summary of DPP4’s immunoregulatory actions including both enzymatic dependent and independent functions is needed. In this article, we will review the recent advances of DPP4 in immune regulation and autoimmune rheumatic disease.

Association between dipeptidyl peptidase-4 inhibitors and increased risk for bullous pemphigoid within 3 months from first use: A 5-year population-based cohort study using the Japanese National Database

AIMS/INTRODUCTION

We assessed the association between dipeptidyl peptidase-4 inhibitors (DPP-4is) and bullous pemphigoid (BP) and time-dependent changes in the risk for developing BP after DPP-4i initiation.

MATERIALS AND METHODS

The present population-based, real-world study was carried out using the Japanese National Database dataset collected between 2013 and 2018. To assess independent correlations between DPP-4is and the development of BP, the self-controlled case series method was used.

RESULTS

Among the cohort followed up for a median of 1,540 days, 53,027 patients were likely to develop BP. The possible incidence rate of BP in all 150,328,339 patients was 10.4/100,000 person-years. Among the 9,705,814 patients with type 2 diabetes, 15,634 were likely to develop BP. The possible incidence rate of BP in patients with type 2 diabetes was 38.1/100,000 person-years, whereas that in patients with type 2 diabetes who did and did not use DPP-4is was 40.7 and 30.0/100,000 person-years, respectively. Analysis of the 28,705 patients with type 2 diabetes likely to develop BP after initial DPP-4i use showed a risk ratio of 2.15 (95% confidence interval [CI] 1.75-2.63), 1.70 (95% CI 1.37-2.11), 1.44 (95% CI 1.15-1.82), 1.25 (95% CI 0.98-1.59), 0.84 (95% CI 0.63-1.10), 0.84 (95% CI 0.64-1.11) and 1.05 (95% CI 0.92-1.20), for the risk period of ≤30, 31-60, 61-90, 91-120, 121-150, 151-180 and 181-365 days, respectively.

CONCLUSIONS

Although DPP-4is were associated with increased risk for BP, the risk was particularly significant within 3 months from first use.

Severe edema and blood blisters of the lower extremities caused by sitagliptin, a dipeptidyl peptidase-4 inhibitor

Severe edema and blood blisters can occur as adverse events associated with sitagliptin. A history of dipeptidyl peptidase-4 inhibitors should be considered when examining patients with edema and blood blisters of uncertain cause.

Gliptin-associated bullous pemphigoid shows peculiar features of anti-BP180 and -BP230 humoral response: results from a multicenter study

BACKGROUND

Recently, several case-control studies demonstrated an association between gliptins and bullous pemphigoid (BP) occurrence. Data on clinical and immunological features of gliptin-associated bullous pemphigoid (GABP) are controversial.

OBJECTIVE

This study aims to clinically and immunologically characterize a large cohort of GABP patients to get insight into the pathophysiology of this emerging drug-induced variant of BP.

METHODS

Seventy-four GABP patients were prospectively enrolled and characterized from nine different Italian Dermatology Units between 2013 and 2020.

RESULTS

Our findings demonstrate that in GABP patients: i) the non-inflammatory phenotype which is characterized by low amounts of circulating and skin infiltrating eosinophils is frequently found; ii) IgG, IgE and IgA humoral response to BP180 and BP230 antigens is reduced in frequency and titers when compared with idiopathic BP; iii) IgG reactivity targets multiple BP180 epitopes other than NC16A.

LIMITATIONS

A limitation of the study is the control group that did not comprise only type 2 diabetes mellitus BP patients.

CONCLUSIONS

GABP patients show peculiar features of anti-BP180 and -BP230 humoral response laying the foundations for diagnostic improvements and to get novel insights into understanding the mechanism of BP onset.

Bullous pemphigoid in diabetic patients treated by gliptins: the other side of the coin

Bullous pemphigoid (BP) is the most common autoimmune bullous skin disease that affects primarily patients older than 60 years. The majority of BP cases are spontaneous, but BP can also be triggered by certain drugs’ exposures. Since 2011, a growing number of observations has been reporting cases of BP in Type 2 diabetic patients. These forms have been linked to the use of a new category of anti-diabetic drugs called dipeptidyl peptidase inhibitors (DPP-4i) or gliptins, but to date, the exact pathophysiological mechanisms underlying this association are not completely elucidated. Although conventional and gliptin-associated BP are thought to share similar clinical and histopathological features, our thorough review of the most recent literature, shows that these 2 forms are quite distinct: DPP-4-i-associated BP seems to appear at an earlier age than spontaneous BP, it may manifest either as a noninflammatory or inflammatory phenotype, while the conventional form presents with a typical inflammatory phenotype. Additionally, an important distinctive histological feature was recently shown in Gliptin-associated BP: these forms may present a less significant eosinophils infiltrate in the upper dermis of peri-blister lesions compared to the skin of patients with spontaneous BP, and this seems a specific feature of the clinically non-inflammatory forms. In accordance with previous literature, we found that the direct immunofluorescence (DIF) gives identical findings in both DPP-4i-associated and conventional forms of BP which is an IgG and complement C3 deposition as a linear band at the dermal–epidermal junction in perilesional skin. Indirect immunofluorescence shows the presence of IgG circulating autoantibodies in the patient's serum which titer does not differ between spontaneous and DPP-4i-associated BP, while the specificity of these autoantibodies, may be different in spontaneous, induced non-inflammatory and induced inflammatory forms, epitope spreading phenomenon seems to play a role in determining these specificities. Further research, based on integrated epidemiological, clinical, histo-immunological and pharmacogenomic approaches, may give more insight into these forms of BP. This combined approach will allow to better define BP endotypes and to unveil the mechanism of spontaneous or drug-induced breakage of the immunotolerance to skin self-antigens.

The pathogeneses of pemphigus and pemphigoid diseases

Autoimmune bullous diseases (AIBDs) are skin disorders which are mainly induced by autoantibodies against desmosomal or hemidesmosomal structural proteins. Previous studies using patients' samples and animal disease models identified target antigens and elucidated the mechanisms of blister formation. Pemphigus has been the subject of more active clinical and basic research than any other AIBD. These efforts have revealed the pathogenesis of pemphigus, which in turn has led to optimal diagnostic methods and novel therapies, such as rituximab. In bullous pemphigoid (BP), studies with passive-transfer mouse models using rabbit anti-mouse BP180 antibodies and studies with passive-transfer or active mouse models using autoantigen-humanized mice elucidated the immune reactions to BP180 in vivo. Recently, dipeptidyl peptidase-4 inhibitors have attracted attention as a trigger for BP. For epidermolysis bullosa acquisita (EBA), investigations using mouse models are actively under way and several molecules have been identified as targets for novel therapies. In this review, we give an overview and discussion of the recent progress in our understanding of the pathogenesis of pemphigus, BP, and EBA. Further studies on the breakdown of self-tolerance and on the identification of key molecules that are relevant to blister formation may expand our understanding of the etiology of AIBDs and lead to the development of novel therapeutic strategies.

DPP-4 Inhibitors and Increased Reporting Odds of Bullous Pemphigoid: A Pharmacovigilance Study of the FDA Adverse Event Reporting System (FAERS) from 2006 to 2020

BACKGROUND

In recent years, an association between dipeptidyl peptidase-4 (DPP-4) inhibitors and bullous pemphigoid has been detected in pharmacovigilance studies in European and Asian countries; however, no pharmacovigilance data have been published yet in the USA.

OBJECTIVE

The objective of this study was to examine the relationship between bullous pemphigoid and DPP-4 inhibitors and other oral diabetes mellitus medications in the FDA Adverse Event Reporting System (FAERS).

METHODS

Case/non-case analyses were performed in the FAERS using data from 2006 to 2020 to examine the reporting odds ratio (ROR) signal for bullous pemphigoid for all classes of oral diabetes medications. These analyses were performed under multiple conditions to control for bias: (1) comparison to all other drugs in the FAERS; (2) comparison to other diabetes medications; and (3) comparison to all other diabetes medications where only a single agent was implicated.

RESULTS

A statistically significant ROR for bullous pemphigoid was found for DPP-4 inhibitors under all conditions: (1) 109.79 (95% confidence interval [CI] 101.61-118.62); (2) 74.46 (95% CI 60.58-91.52); and (3) 35.94 (95% CI 27.91-46.28). A larger signal was seen for non-US Food and Drug Administration (FDA)-approved (anagliptin, vildagliptin, teneligliptin) vs FDA-approved DPP-4 inhibitors (alogliptin, linagliptin, saxagliptin, sitagliptin), likely because of an overestimation of the ROR for non-FDA-approved drugs. The largest signal was seen under conditions 1 and 2 with vildagliptin (1) 1022.83 (95% CI 909.45-1150.35) and (2) 158.84 (95% CI 127.01-198.66) followed by anagliptin (1) 628.63 (95% CI 221.36-1785.24) and (2) 60.64 (95% CI 20.98-175.26), alogliptin, teneligliptin, linagliptin, sitagliptin, and saxagliptin. Under condition 3, the largest signal was seen with linagliptin 122.25 (95% CI 93.96-159.07). Both metformin and the sulfonylureas had a significant ROR under condition 2 [3.42 (95% CI 3.01-3.89) and 2.07 (95% CI 1.66-2.57) respectively]; however, this association was not present under condition 3 as only confounded cases occurred, and a large majority of reported cases had concurrent exposure to a DPP-4 inhibitor.

CONCLUSIONS

Our findings support an association between DPP-4 inhibitors and bullous pemphigoid. This association was maintained under controls to limit bias and falsely elevated signal, including controlling for disease state and cases with multiple drug exposures. Non-FDA-approved DPP-4 inhibitors had a larger ROR compared with FDA-approved DPP-4 inhibitors, likely owing to fewer reported adverse effects overall for non-FDA-approved drugs in FAERS.

Atypical Bullous Pemphigoid After Linagliptin Intake

BACKGROUND Bullous pemphigoid is a common pruritic skin lesion reported in elderly patients. It is caused by an immunologic reaction between autoantibodies and hemidesmosome proteins of epithelial cells. The disease is characterized by a symmetrical blister distribution on the body. Diagnosis should be suspected in elderly patients presenting with a tense blister on normal-appearing skin or on an erythematous base. In the literature, several forms of typical bullous pemphigoid after treatment with linagliptin have been reported. However, this is the first reported case of atypical nonbullous pemphigoid after linagliptin intake. CASE REPORT A 77-year-old woman presented with multiple erythematous papules and nodules on the upper extremities and trunk. The patient was being treated with linagliptin for diabetes. Diagnosis was made with biopsy and histopathological studies, followed by direct immunofluorescence. The histopathological study showed a subepidermal blister with an underlying polymorphous infiltrate, mainly of an eosinophilic profile. Direct immunofluorescence showed linear IgG and C3 antibodies to hemidesmosomes at the lamina lucida of the basement membrane. Thus, the diagnosis of atypical nonbullous pemphigoid was made. CONCLUSIONS This report emphasizes the great variety of bullous pemphigoid presentation and the need for a greater level of awareness of the adverse effects of linagliptin. Thus, atypical nonbullous pemphigoid should be considered among the potential differential diagnoses in patients with multiple erythematous papules and nodules on the upper extremities and trunk.

Dipeptidyl peptidase-4 inhibitor-induced autoimmune diseases: Current evidence

Dipeptidyl peptidase-4 inhibitors (DPP-4i) have an important place in the management of type 2 diabetes. The DPP-4 enzyme is ubiquitously distributed throughout the human body and has multiple substrates through which it regulates several important physiological functions. DPP-4 regulates several immune functions, including T-cell activation, macrophage function, and secretion of cytokines. Studies have reported an increase in autoimmune diseases like bullous pemphigoid, inflammatory bowel disease, and arthritis with DPP-4i use. The relationship of DPP-4i and autoimmune diseases is a complex one and warrants further research into the effect of DPP-4 inhibition on the immune system to understand the pathogenesis more clearly. Whether a particular cluster of autoimmune diseases is associated with DPP-4i use remains an important contentious issue. Nevertheless, a heightened awareness from the clinicians is required to identify and treat any such diseases. Through this review, we explore the clinical and pathophysiological characteristics of this association in light of recent evidence.

The impact of diabetes mellitus on medical complication and mortality rates among inpatients with bullous pemphigoid

BACKGROUND

There is currently limited population-based data on the effect of type 2 diabetes mellitus (T2DM) on bullous pemphigoid (BP) inpatients.

AIMS

To evaluate the relative comorbidities, medical complications, and mortality rates between BP inpatients with and without T2DM.

METHODS

All inpatients with a primary BP diagnosis in the National Inpatient Sample from 2003 to 2012 were queried. BP inpatients with or without T2DM were compared to identify disparities in relative comorbidities and medical complications. Comorbidities were established using the Agency for Healthcare Research and Quality standardized values. Medical complications were classified using ICD-9 codes.

RESULTS

Of the 1978 BP patients identified, 660 (33.4%) had a concurrent diagnosis of T2DM. These patients had significantly higher rates of concurrent comorbidities, including chronic renal failure, congestive heart failure, iron deficiency anemia, hypertension, obesity, and peripheral vascular disease. On bivariate analysis, T2DM patients also had significantly higher rates of medical complications including acute kidney injury (14.5% vs. 10.1%, p = 0.004) and venous thromboembolism (1.8% vs. 0.5%, p = 0.012). On multivariable-adjusted analysis, the odds of venous thromboembolism (OR = 3.01, p = 0.027) remained increased. Inpatient mortality did not differ between the groups.

CONCLUSIONS

Our findings suggest that BP inpatients with T2DM have a greater medical comorbidity and complication burden. However, inpatient mortality was not increased.

Dipeptidyl peptidase 4 inhibitor-associated mucous membrane pemphigoid

Dipeptidyl peptidase 4 inhibitors (DPP-4i) are associated with an increased risk of developing bullous pemphigoid (BP) in patients with diabetes. Autoantibodies targeting epitopes on the processed BP180, 120-kDa (LAD-1), and 97-kDa (LABD97) linear immunoglobulin (Ig)A dermatosis antigens are the major autoantibodies in DPP-4i-associated BP. However, no case of mucous membrane pemphigoid (MMP) developing during treatment with DPP-4i has been reported. We report a case of MMP associated with DPP-4i. A man in his late 70s presented with oral mucous membrane erosion and a few blisters on his upper chest and back. He had used linagliptin for diabetes for over 1 year when he presented. The immunological characteristics were similar to DPP4i-associated BP: higher reactivity to LAD-1 and LABD97 than to the full-length BP180. The aphthae achieved remission after oral linagliptin was replaced with sitagliptin. However, 6 months later, the aphthae relapsed and any DPP-4i was discontinued. The aphthae disappeared, and now he is completely free from lesions associated with MMP. This case suggests that the DPP-4i may have shared roles in the production of IgG antibodies to LAD-1 or to LABD97 in the pathogenesis of DPP-4i-associated BP and MMP. Our case highlights the possibility of overlooking the mild MMP in DPP-4i-treated diabetes patients with mucosal lesions.

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.

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.

Defining dipeptidyl peptidase-4 inhibitors-related bullous pemphigoid: A single-centre retrospective study

BACKGROUND

Many studies have corroborated the association of dipeptidyl peptidase-4 inhibitors (DPP4i) use with bullous pemphigoid (BP). It has been speculated that this drug-induced variant presents with a different clinical spectrum than conventional BP.

OBJECTIVE

To determine the prevalence of DPP4i-induced cases of BP and to evaluate whether gliptin-related BP has specific clinicopathological and immunological features.

METHODS

We conducted a retrospective, observational study of BP cases attended at our centre between January 2000 and June 2020. Epidemiological, clinical, histopathological and laboratory data were collected.

RESULTS

A total of 257 cases of BP were collected; 51 (24.3%) were on treatment with DPP4i. When analysing DPP4i-induced BP cases, generalized BP was the predominant pattern and scalp/mucosal involvement was found in 13 patients. Gliptin-related BP cases were associated to a decrease in the eosinophilic infiltrate (p = 0.000) and both the detection rate and concentration of anti-BP180 IgG were lower (p = 0.004, p = 0.001, respectively) than non-DPP4i cases.

LIMITATIONS

Retrospective, single-centre study.

CONCLUSION

Our large DPP4i-induced BP case series has highlighted that DPP4i-induced BP is characterized by generalized lesions and scalp involvement. Lower titres of anti-BP180 antibodies and a decrease in eosinophils infiltrating into the skin may be distinct features of DPP4i-related BP.

Immunobullous disease

Immunobullous diseases are blistering cutaneous disorders that are caused by pathogenic antibodies binding to protein targets within the skin. There are a range of immunobullous disorders with characteristic morphology that relates to the structural properties of the target protein. In this article we will describe the pathogenesis, clinical features and treatment of the most common immunobullous disorders.

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).

Evaluation of Risk of Bullous Pemphigoid With Initiation of Dipeptidyl Peptidase-4 Inhibitor vs Second-generation Sulfonylurea

Importance

Despite several recent reports on the elevated risk of bullous pemphigoid in patients with type 2 diabetes treated with dipeptidyl peptidase-4 (DPP-4) inhibitors, evidence on the absolute risk and comparative safety against other antidiabetics is limited.

Objective

To characterize the incidence rate of bullous pemphigoid associated with DPP-4 inhibitor use compared with second-generation sulfonylureas.

Design, Setting, and Participants

This cohort study used data from 2 large commercial insurance claims databases (Optum Clinformatics Data Mart from October 17, 2006, to December 31, 2018, and IBM MarketScan Research Database from October 17, 2006, to December 31, 2017) and Medicare data from January 1, 2006, to December 31, 2016. Patients with type 2 diabetes who initiated treatment with DPP-4 inhibitors or second-generation sulfonylurea were included.

Main Outcomes and Measures

The primary outcome of the study was bullous pemphigoid, identified using diagnosis codes. After 1:1 propensity score matching, the incidence rates of bullous pemphigoid and the hazard ratios (HRs) with 95% CIs comparing patients who initiated DPP-4 inhibitor and second-generation sulfonylurea therapy were estimated. Subgroup analyses by age, sex, race, and individual DPP-4 agents were performed. The results from each database were pooled using inverse-variance fixed-effects meta-analysis.

Results

A total of 1 664 880 patients who initiated DPP-4 inhibitors (51.0% female; mean [SD] age, 63.9 [9.7] years) and sulfonylurea (50.4% female; mean [SD] age, 63.9 [9.9] years) were included. The incidence rate of bullous pemphigoid per 1000 person-years was 0.42 in the DPP-4 inhibitor group vs 0.31 in the sulfonylurea group (HR, 1.42; 95% CI, 1.17-1.72). Higher rates per 1000 person-years for DPP-4 inhibitor vs sulfonylurea groups were seen in those who were 65 years or older (0.79 vs 0.49; HR, 1.62; 95% CI, 1.32-1.99), white (0.93 vs 0.54; HR, 1.70; 95% CI, 1.30-2.24), and treated with linagliptin (1.20 vs 0.55; HR, 1.68; 95% CI, 1.16-2.43).

Conclusions and Relevance

This study found that patients who initiated DPP-4 inhibitor therapy had higher risk of bullous pemphigoid than those who initiated second-generation sulfonylurea therapy. Clinicians should be aware of this rare adverse effect of DPP-4 inhibitors in subgroups of patients who are older, white, and linagliptin users.

Clinical, Laboratory and Histological Features of Dipeptidyl Peptidase-4 Inhibitor Related Noninflammatory Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease of elderly patients that has shown increasing incidence in the last decades. Higher prevalence of BP may be due to more frequent use of provoking agents, such as antidiabetic dipeptidyl peptidase-4 inhibitor (DPP4i) drugs. Our aim was to assess DPP4i-induced bullous pemphigoid among our BP patients and characterize the clinical, laboratory and histological features of this drug-induced disease form. In our patient cohort, out of 127 BP patients (79 females (62.2%), 48 males (37.7%)), 14 (9 females and 5 males) were treated with DPP4i at the time of BP diagnosis. The Bullous Pemphigoid Disease Area Index (BPDAI) urticaria/erythema score was significantly lower, and the BPDAI damage score was significantly higher in DPP4i-BP patients compared to the nonDPP4i group. Both the mean absolute eosinophil number and the mean periblister eosinophil number was significantly lower in DPP4i-BP patients than in nonDPP4i cases (317.7 ± 0.204 vs. 894.0 ± 1.171 cells/μL, p < 0.0001; 6.75 ± 1.72 vs. 19.09 ± 3.1, p = 0.0012, respectively). Our results provide further evidence that DPP4i-associated BP differs significantly from classical BP, and presents with less distributed skin symptoms, mild erythema, normal or slightly elevated peripheral eosinophil count, and lower titers of BP180 autoantibodies. To our knowledge, this is the first case series of DPP4i-related BP with a non-inflammatory phenotype in European patients.

Dipeptidyl peptidase-4 inhibitor treatment and the risk of bullous pemphigoid and skin-related adverse events: A systematic review and meta-analysis of randomized controlled trials

AIMS

This meta-analysis aimed to evaluate the risk of developing bullous pemphigoid (BP) and other skin-related adverse events (AEs) in patients with type 2 diabetes (T2DM) undergoing dipeptidyl peptidase-4 inhibitor (DPP-4i) treatment in randomized controlled trials (RCTs).

METHODS

In this meta-analysis, the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were searched for RCTs, which involve patients with T2DM reporting skin-related AEs. RCTs that comparatively evaluated the effects of DPP-4i treatment and placebo on patients with T2DM and reported skin-related AEs were included in the analysis. The odds ratio (OR) and 95% confidence interval (CI) were calculated using the Peto's methods. The GRADE approach was used to rate the quality of evidence.

RESULTS

A total of 46 randomized placebo-controlled trials, including 3 trials with reports of BP (n = 38 011), that reported skin-related AEs were included (n = 59 332). Compared to the placebo group, the risk of developing BP was significantly higher in the DPP-4i treatment group (OR = 7.38, 95% CI 2.00-27.25, I² = 0%, P = .003; quality rating: very low). Additionally, DPP-4i treatment was associated with an increased overall risk of developing skin-related AEs (OR = 1.22, 95% CI 1.02-1.46, I² = 32%, P = .03; quality rating: moderate).

CONCLUSIONS

This meta-analysis suggested that treatment with DPP-4is, including sitagliptin, saxagliptin, and linagliptin, was associated with an increased risk of developing BP. Additionally, the risk of developing skin-related AEs increased when all DPP-4is were combined. Skin lesion, especially BP, should be monitored in patients with diabetes undergoing DPP-4i treatment. Future studies should evaluate the susceptible population and develop strategies for early detection of skin-related AEs.

A History of Asthma Increases the Risk of Bullous Pemphigoid: Insights from a Large Population-Based Study

BACKGROUND

Bullous pemphigoid (BP) and asthma both share a pathogenic role of eosinophils and immunoglobulin E (IgE) and favorable response for corticosteroids and omalizumab. However, the association between these conditions is yet to be investigated. We sought to estimate the risk of having BP among patients previously diagnosed with asthma and to characterize patients with coexistent BP and asthma.

METHODS

Utilizing the dataset of Clalit Health Services, a population-based case-control study was conducted comparing BP patients (n = 3,924) with age-, sex-, and ethnicity-matched control subjects (n = 19,280) regarding the presence of asthma. Logistic regression models were utilized for univariate and multivariate analyses.

RESULTS

The prevalence of preceding asthma was higher in patients with BP than in control subjects (11.1 vs. 7.9%, respectively; p < 0.001). A history of asthma was associated with a 50% increase in the risk of BP (OR 1.45; 95% CI 1.30-1.62). The association was not altered greatly after adjusting for demographics (adjusted OR 1.43; 95% CI 1.28-1.61) as well as for demographics and comorbidities (adjusted OR 1.40; 95% CI 1.25-1.57). The average (SD) latency between the diagnosis of asthma and the development of BP was 12.5 (14.7) years. When compared with other patients with BP, those with a dual diagnosis of BP and asthma were older, had higher BMI, and were more frequently managed by corticosteroids and immunosuppressive and immunomodulatory adjuvants.

CONCLUSIONS

Asthma confers a predisposition to the development of BP. Awareness of this association may be of help for physicians managing patients with BP and asthma. Further research is required to elucidate the mechanism underlying this observation.