Linagliptin‐associated bullous pemphigoid that was most likely caused by IgG autoantibodies against the midportion of BP 180

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.

Clinical Phenotypes and the Clinical Course of Bullous Pemphigoid Receiving Dipeptidyl Pepitidase-4 Inhibitor Treatment: An Analysis of Cases in a Single Japanese Center

Objective Several studies have shown an increased risk of bullous pemphigoid (BP) when receiving dipeptidyl pepitidase-4 inhibitor (DPP-4i) treatment. The present study explored the associations of DPP-4i treatment with the clinical phenotypes and clinical course of BP. Methods We analyzed data of 146 patients with BP at Tokai University School of Medicine from December 1, 2009, to December 31, 2021. We obtained data by a retrospective medical record review and compared the bullous pemphigoid disease area index (BPDAI) between diabetes patients receiving DPP-4i treatment and those not receiving DPP-4i treatment. We employed multivariable linear regression models to explore the association between the DPP-4i treatment and the BPDAI scores. Results Among 53 BP patients with diabetes, 33 had developed BP during treatment with DPP-4i agents, among which vildagliptin was the most frequently used. The urticaria/erythema scores of the BPDAI were significantly lower in patients who developed BP while receiving DPP-4i treatment than among others. Of note, 69.2% of the patients who stopped DPP-4i treatment experienced complete remission, and the clinical course was more favorable in patients with lower scores for urticaria/erythema than among others. Conclusion These findings suggest that, in patients who developed BP while receiving DPP-4i treatment, a noninflammatory phenotype may indicate a high likelihood that DPP-4i treatment contributes to the development of BP. The discontinuation of DPP-4i should be carefully considered in close consultation with dermatologists.

Efficacy and safety of tetracyclines for pemphigoid: a systematic review and meta-analysis

The aim of this review was to evaluate the efficacy and safety of tetracyclines for treatment of pemphigoid. We searched PubMed, EMBASE, Ovid, Web of Science, and the Cochrane Library for studies involving pemphigoid patients treated with tetracyclines published in English before 29 February 2020. References of included studies were also screened to widen the scope of the literature search. Data regarding predefined clinical outcomes of 341 patients from 77 studies were extracted and analyzed. A meta-analysis was conducted on the basis of 4 studies including 2 randomized controlled trials and 2 comparative studies. The patients had a mean age of 74.60 ± 13.18 years, 45.4% were males, and 54.6% were females. There were 185 patients with mild-to-moderate and 143 patients with severe disease. The average initial doses were 1.62 ± 0.39 g/day for tetracycline, 0.20 ± 0.01 g/day for doxycycline, and 0.11 ± 0.05 g/day for minocycline. The average time on tetracyclines was 3.74 ± 5.99 months, and 261 (81.3%) patients reported partial or complete remission. Relapses occurred in 72 (28.3%) cases. Adverse effects were experienced by 130 (41.9%) patients. The pooled ORs for short-term effectiveness, relapse, adverse effects, and 1-year survival in patients treated with oral tetracyclines vs. systemic corticosteroids were 0.40 (95% CI, 0.22-0.76), 0.69 (95% CI, 0.44-1.10), 0.47 (95% CI, 0.27-0.82) and 2.02 (95% CI, 1.16-3.50), respectively. Compared to doxycycline and minocycline, tetracycline was significantly associated with better treatment outcomes and fewer adverse effects (p < 0.05). This review revealed tetracyclines' efficacy and safety in pemphigoid treatment and may offer support for clinical use of tetracyclines in pemphigoid.

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.

Dipeptidyl peptidase-4 inhibitor-related bullous pemphigoid: A comparative study of 100 patients with bullous pemphigoid and diabetes mellitus

Dipeptidyl peptidase-4 inhibitor (DPP4i)-associated bullous pemphigoid (BP) has been emerging but whether it has genotype or phenotype differences from idiopathic BP (IBP) remains to be determined. We aimed to compare clinical characteristics, genetic susceptibility, laboratory features, disease activity, and outcomes between DPP4i-associated BP (DBP) and IBP occurring among patients with diabetes mellitus type 2 (T2DM). Medical records of patients diagnosed with BP and T2DM from January 2009 to December 2019 were retrospectively reviewed, and patients were categorized into DBP or IBP groups. Of 100 patients, 23 had DBP and 77 had IBP. There was no difference in the Bullous Pemphigoid Disease Activity Index score between the two groups; however, the score for urticaria and erythema was less in DBP (p < 0.001), indicating a non-inflammatory phenotype. The HLA-DQB1*03:01 allele was more commonly present in the DBP than IBP cases (odds ratio = 5.33 [95% confidence interval, 1.11-28.59], p = 0.016). The absolute eosinophil count was significantly lower in the DBP group (p = 0.002). Likewise, eosinophilic spongiosis was found less frequently in DBP cases (p = 0.005). Patients in the DBP group had a significantly higher percentage of complete remission on therapy compared to the IBP counterpart (p = 0.026) after DPP4i discontinuation. Moreover, the mean maximum dosage of prednisolone administrated per patient was significantly lower in drug-related cases (p = 0.012). In conclusion, our cohort in Thai patients with T2DM confirms the differences between phenotype and genotype characteristics of DBP and IBP. We emphasize the importance of drug discontinuation in all DPP4i-related cases because doing so may lead to a better disease outcome.

Bullous Pemphigoid and Diabetes medications: A disproportionality analysis based on the FDA Adverse Event Reporting System

Background: The world's first Diabetes Medications (Insulin) was marketed in October 1923. Some studies suggested the association of diabetes medications with Bullous Pemphigoid (BP), especially the Dipeptidyl Peptidase 4 (DPP-4) inhibitors. The study aims to detect an association between diabetes medications (focusing on DPP-4 inhibitors) and bullous pemphigoid based on FDA Adverse Event Reporting System (FAERS). Methods: All spontaneous reports of diabetes medications inhibitors-related BP recorded in the FAERS between March 2004 and August 2020 were included in the present study. Disproportionality analysis was performed to find the signal between diabetes medications and BP. The Chi-Squared with Yates' correction (χ² _Yates), proportional reporting ratio (PRR) and the lower limit of the 95% confidence interval of the Reporting Odds Ratio (ROR₀₂₅) were calculated as a measure. A signal was detected when ROR₀₂₅ > 1, PRR > 2, χ² _Yates > 4 and at least 3 cases. Results: There were 3770 reports for BP in FAERS. The strongest signal for diabetes medications-BP association were DDP-4 inhibitors (ROR₀₂₅: 13.700, PRR: 15.408), followed by Meglitinides (ROR₀₂₅: 12.708, PRR: 16.777), Non-sulfonylureas (ROR₀₂₅: 6.434, PRR: 7.016), Alpha-glucosidase inhibitors (ROR₀₂₅: 6.105, PRR: 10.738), Sulfonylureas (ROR₀₂₅:2.655, PRR: 3.200). Conclusions: This study detected a strong signal between BP and DDP-4 inhibitors, alpha-glucosidase inhibitors, meglitinides, non-sulfonylureas, and sulfonylureas in FAERS. The signal was significantly higher with alogliptin than with the other DPP-4 inhibitors. The study doesn't suggest the association between the incretin mimetics, insulin, SGLT-2 inhibitors, thiazolidinediones and BP in FAERS.

The role of Dipeptidyl Peptidase-4 in cutaneous disease

Dipeptidyl peptidase-4 (DPP4) is a multifunctional, transmembrane glycoprotein present on the cell surface of various tissues. It is present in multiple molecular forms including cell surface and soluble. The role of DPP4 and its inhibition in cutaneous dermatoses have been a recent point of investigation. DPP4 exerts a notable influence on T-cell biology, the induction of skin-specific lymphocytes, and the homeostasis between regulatory and effector T cells. Moreover, DPP4 interacts with a broad range of molecules, including adenosine deaminase, caveolin-1, CXCR4 receptor, M6P/insulin-like growth factor II-receptor and fibroblast activation protein-α, triggering downstream effects that modulate the immune response, cell adhesion and chemokine activity. DPP4 expression on melanocytes, keratinocytes and fibroblasts further alters cell function and, thus, has crucial implications in cutaneous pathology. As a result, DPP4 plays a significant role in bullous pemphigoid, T helper type 1-like reactions, cutaneous lymphoma, melanoma, wound healing and fibrotic disorders. This review illustrates the multifactorial role of DPP4 expression, regulation, and inhibition in cutaneous diseases.

Bullous Pemphigoid: Trigger and Predisposing Factors

Bullous pemphigoid (BP) is the most frequent autoimmune subepidermal blistering disease provoked by autoantibodies directed against two hemidesmosomal proteins: BP180 and BP230. Its pathogenesis depends on the interaction between predisposing factors, such as human leukocyte antigen (HLA) genes, comorbidities, aging, and trigger factors. Several trigger factors, such as drugs, thermal or electrical burns, surgical procedures, trauma, ultraviolet irradiation, radiotherapy, chemical preparations, transplants, and infections may induce or exacerbate BP disease. Identification of predisposing and trigger factors can increase the understanding of BP pathogenesis. Furthermore, an accurate anamnesis focused on the recognition of a possible trigger factor can improve prognosis by promptly removing it.

Clinical and immunological profile of patients with dipeptidyl peptidase-4 inhibitor-associated bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune blistering disease caused by antibodies against the hemidesmosomal BP180 and/or BP230 proteins. There is an increasing evidence that the use of dipeptidyl peptidase-4 inhibitors, also known as gliptins, increases the risk for BP. The gliptins more frequently associated with BP are vildagliptin and sitagliptin. Clinical, immunological and pathological features of gliptin-associated BP have been reported to be distinct, compared to classic BP.

METHODS

In this study, 15 gliptin-associated BP (g-BP) cases have been compared with 16 consecutive idiopathic BP (i-BP) to clarify whether g-BP has distinctive clinical and immunopathological characteristics. Comorbidities, concomitant treatments, latency of the onset of the disease and the time to achieve the remission were also considered.

RESULTS

The mean latency from drug intake to g-BP appearance was 9.4 months (median 10, inter-quartile range [IQR] 6-12). There were no differences in sex and age prevalence between the two groups (g-BP median age 77 years, IQR: 70-84; i-BP: 81 years, IQR: 72-86). There were no differences as far clinical presentation including disease severity, lesions types (urticarial and bullous) or mucosal involvement between g-BP and i-BP cases. The median antibody anti-BP180 and anti-BP230 titers was also similar between the two groups with 29.1 UI/mL (IQR: 12.9-65.3) and 11.8 UI/mL (IQR: 1.7-26.3), respectively. Gliptins were withdrawn in ten out of 15 patients and remission was achieved with systemic corticosteroids (0.3-0.7 mg/Kg daily) alone or in association with doxycycline (100-200 mg daily) within a mean of 8 months.

CONCLUSIONS

A non-inflammatory phenotype with less erythema, fewer urticarial lesions and fewer eosinophils in skin lesions has been associated with gliptins in selected Japanese BP populations. As reported in European studies, no significant differences among the considered variables in the g-BP and i-BP cases have been found in our study.

Bullous pemphigoid associated with dipeptidyl peptidase-4 inhibitors. A case series and analysis of cases reported in the Spanish pharmacovigilance database

BACKGROUND

Bullous pemphigoid (BP) has been associated with dipeptidyl peptidase-4 inhibitors (DPP4i). Clinical features, outcomes, and risk of BP for new DPP4i (linagliptin, saxagliptin, and alopgliptin) are not well established. Comparison of risk of BP appearance for DPP4i and other oral antidiabetic drugs (OADs) such as sodium glucose cotransporter 2 inhibitors has not been studied to date.

OBJECTIVES

To describe the prevalence, sociodemographic, clinical, and histopathological characteristics, and outcome after drug withdrawal in DPP-4i-associated BP cases from our hospital. To review all Spanish spontaneous notifications of BP where DPP4i or OADs were included as suspected drugs and calculate the reporting odds ratios (RORs).

METHODS

A retrospective observational study was performed examining the association between DDP4i and BP. Clinical features and RORs were analyzed. Data from the Spanish Pharmacovigilance System (SEFV) are included.

RESULTS

In our center, 28 of 89 patients with BP (31.5%) were under DPP4i treatment; 53.6% were male, and mean age was 80.8 years. BP debuted the first year after DPP4i in 57.2%. BP control was achieved within 3.7 months after drug withdrawal. Regarding SEFV, 22 of 972 spontaneous notifications were related to BP and DPP4i. RORs were superior for DPP4i compared to other OADs. Vildagliptin had the highest ROR.

CONCLUSIONS

We present the largest DPP4i-induced BP case series in a single center, with a detailed study of the sociodemographic, clinical, and histopathological characteristics of each patient, and their treatment and outcome. Vildagliptin had the highest risk. DPP4i-associated BP does not seem to have specific clinical characteristics.

Linagliptin-associated bullous pemphigoid treated with rituximab

Dipeptidyl peptidase 4 (DPP-4) inhibitors are increasingly used these days in management of diabetes. There has been reported in a few case reports of increasing association between DPP-4 inhibitor use and bullous pemphigoid (BP). We report a case of association between linagliptin use and BP and subsequent treatment with rituximab.

Dipeptidyl Peptidase-4 Inhibitor-Associated Bullous Pemphigoid

Bullous pemphigoid (BP) is an organ-specific autoantibody-mediated blistering skin disease that mainly affects the elderly. Typical clinical features include the widespread blisters, often preceded by and/or associated with itchy urticarial or eczema-like lesions. BP patients have circulating autoantibodies against BP180 and/or the plakin family protein BP230 both of which are components of hemidesmosomes in basal keratinocytes. Most BP autoantibodies particularly target the epitopes within the non-collagenous NC16A domain of BP180. Clinical findings and murine models of BP have provided evidence of a pathogenic role of anti-NC16A autoantibodies. However, it is largely unknown what triggers the breakage of immunotolerance against BP180 in elderly individuals. The incidence of BP has been increased over the past two decades in several countries. Aside from aging populations, the factors behind this phenomenon are still not fully understood. Neurodegenerative diseases such as multiple sclerosis, Parkinson's disease, and certain dementias are independent risk factors for BP. Recently several case reports have described BP in patients with diabetes mellitus (DM) patients who have been treated with dipeptidyl peptidase-4 inhibitors (DPP-4i or gliptins), which are a widely used class of anti-DM drugs. The association between the use of DPP-4is, particularly vildagliptin, and BP risk has been confirmed by several epidemiological studies. Evidence suggests that cases of gliptin-associated BP in Japan display certain features that set them apart from cases of “regular” BP. These include a “non-inflammatory” phenotype, targeting by antibodies of different immunodominant BP180 epitopes, and a specific association with the human leukocyte antigen (HLA) types. However, recent studies in European populations have found no major differences between the clinical and immunological characteristics of gliptin-associated BP and “regular” BP. The DPP-4 protein (also known as CD26) is ubiquitously expressed and has multiple functions in various cell types. The different effects of the inhibition of DPP-4/CD26 activity include, for example, tissue modeling and regulation of inflammatory cells such as T lymphocytes. Although the pathomechanism of gliptin-associated BP is currently largely unknown, investigation of the unique effect of gliptins in the induction of BP may provide a novel route to better understanding of how immunotolerance against BP180 breaks down in BP.

Cutaneous Adverse Effects of Diabetes Mellitus Medications and Medical Devices: A Review

Diabetes mellitus is one of the most prevalent chronic diseases in the USA. If uncontrolled, diabetes can lead to devastating complications. Diabetes medications and medical devices largely contribute to the significant financial expense that the disease inflicts on affected individuals and society. Alongside significant economic burden, there are numerous cutaneous adverse effects associated with diabetes medications and medical devices. Despite the large and increasing number of individuals living with diabetes and the wide use of the related medications and medical devices, there is limited literature that comprehensively documents their cutaneous adverse effects. These cutaneous adverse effects are significant as they can worsen glycemic control, increase disease distress, and may increase risk of associated complications. Thus, it is important that providers can recognize these cutaneous adverse effects, identify the culprit agents, and can properly manage them. In this article, we provide a critical review of the cutaneous adverse effects of medications and devices used in the management of diabetes and provide insight into risk factors and prevention and an overview of therapeutic management. An emphasis is placed on clinical recognition and treatment for use of the medical providers who, regardless of practice setting, will treat patients with diabetes.

Higher Frequency of Dipeptidyl Peptidase-4 Inhibitor Intake in Bullous Pemphigoid Patients than in the French General Population

Dipeptidyl peptidase-4 inhibitors have been suspected to induce bullous pemphigoid (BP). The objective of this study was to compare the observed frequency of gliptin intake in a large sample of 1,787 BP patients diagnosed between 2012 and 2015 in France, with the expected frequency after indirect age standardization on 225,412 individuals extracted from the database of the National Healthcare Insurance Agency. The secondary objective was to assess the clinical characteristics and the course of gliptin-associated BP, depending on whether gliptin was continued or stopped. The observed frequencies of intake of the whole gliptin class and that of vildagliptin in the BP population were higher than those in the general population after age standardization (whole gliptin class: 6.0%; 95% confidence interval = 4.9-7.1% vs. 3.6%, observed-to-expected drug intake ratio = 1.7; 95% confidence interval = 1.4-2.0; P < 0.0001; vildagliptin = 3.3%; 95% confidence interval = 2.5-4.1% vs. 0.7%, ratio = 4.4; 95% confidence interval = 3.5-5.7; P < 0.0001). The association of any gliptin+metformin was also higher than in the general population, ratio = 1.8 (95% confidence interval = 1.3-2.4; P < 0.0001). Gliptin-associated BP had no specific clinical characteristics. Gliptin was stopped in 48 (45.3%) cases. Median duration to achieve disease control, rate, and delay of relapse were not different whether gliptin was stopped or continued. This study strongly supports the association between gliptin intake, particularly vildagliptin, and the onset of BP.

Bullous pemphigoid induced by dipeptidyl peptidase-4 inhibitors. Eight cases with clinical and immunological characterization

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors have increasingly been identified as causative agents of bullous pemphigoid. The clinical and immunological characteristics of this pemphigoid variant are still unclear. The objective of our study was to analyze the clinical and immunological features of patients with pemphigoid induced by DPP-4 inhibitors.

METHODS

All patients diagnosed with DPP-4 inhibitor-associated bullous pemphigoid at dermatology departments in three Spanish centers during the period 2013 to 2015 were included. ELISA assays for the NC16A domain of BP180 and BP230 were performed. Immunoblot studies using epidermal/dermal extracts and the C-terminal, NC16A and LAD-1 regions of BP180 were also carried out.

RESULTS

A total of eight patients were identified (5 treated with vildagliptin, 2 with linagliptin, and one with sitagliptin). Of these, four presented the classical inflammatory phenotype of bullous pemphigoid and four a noninflammatory phenotype. The ELISA for BP180 (NC16A domain) was positive in six patients at diagnosis. Most patients reacted to more than one BP180 antigenic site (LAD-1 and/or C-terminal domain) on the immunoblot. Two patients showed no reaction against the NC16A domain of BP180 on either the ELISA or immunoblot but recognized either LAD-1 or both LAD-1 and the C-terminal domain. Only one of the NC16A-negative patients had a noninflammatory subtype of bullous pemphigoid.

CONCLUSIONS

Patients with DPP-4 inhibitor-induced BP may present either an inflammatory or a noninflammatory phenotype of BP. IgG response against other BP180 regions different from the NC16A domain, such as LAD-1 and the C-terminal domain, could be pathogenically relevant to the onset of DPP-4 inhibitor-induced BP.

Gliptin Accountability in Mucous Membrane Pemphigoid Induction in 24 Out of 313 Patients

Mucous membrane pemphigoids (MMPs) and bullous pemphigoid (BP) are autoimmune bullous diseases that share physiopathological features: both can result from autoantibodies directed against BP180 or BP230 antigens. An association has been reported between BP and intake of gliptins, which are dipeptidyl peptidase-IV inhibitors used to treat type 2 diabetes mellitus. Clinical and immunological differences have been reported between gliptin-induced BPs and classical BPs: mucosal involvement, non-inflammatory lesions, and target BP180 epitopes other than the NC16A domain. Those findings accorded gliptins extrinsic accountability in triggering MMP onset. Therefore, we examined gliptin intrinsic accountability in a cohort of 313 MMP patients. To do so, we (1) identified MMP patients with gliptin-treated (challenge) diabetes; (2) selected those whose interval between starting gliptin and MMP onset was suggestive or compatible with gliptin-induced MMP; (3) compared the follow-ups of patients who did not stop (no dechallenge), stopped (dechallenge) or repeated gliptin intake (rechallenge); (4) compared the clinical and immunological characteristics of suggestive-or-compatible-challenge patients to 121 never-gliptin-treated MMP patients serving as controls; and (5) individually scored gliptin accountability as the trigger of each patient's MMP using the World Health Organization-Uppsala Monitoring Center, Naranjo- and Begaud-scoring systems. 17 out of 24 gliptin-treated diabetic MMP patients had suggestive (≤12 weeks) or compatible challenges. Complete remission at 1 year of follow-up was more frequent in the 11 dechallenged patients. One rechallenged patient's MMP relapsed. These 17 gliptin-treated diabetic MMP patients differed significantly from the MMP controls by more cutaneous, less buccal, and less severe involvements and no direct immunofluorescence IgA labeling of the basement membrane zone. Multiple autoantibody-target antigens/epitopes (BP180-NC16A, BP180 mid- and C-terminal parts, integrin α6β4) could be detected, but not laminin 332. Last, among the 24 gliptin-treated diabetic MMP patients, five had high (I4-I3), 12 had low (I2-I1) and 7 had I0 Begaud intrinsic accountability scores. These results strongly suggest that gliptins are probably responsible for some MMPs. Consequently, gliptins should immediately be discontinued for patients with a positive accountability score. Moreover, pharmacovigilance centers should be notified of these events.

Bullous Pemphigoid Triggered by Thermal Burn Under Medication With a Dipeptidyl Peptidase-IV Inhibitor: A Case Report and Review of the Literature

Bullous pemphigoid (BP) is a common autoimmune blistering disease in which autoantibodies mainly target the hemidesmosomal component BP180 (also known as type XVII collagen) in basal keratinocytes. Various triggering factors are known to induce BP onset, including radiotherapy, burns, ultraviolet exposure, surgery, and the use of dipeptidyl peptidase-IV inhibitors (DPP4i), which are widely used antihyperglycemic drugs. Here, we present a case of BP triggered by a thermal burn under medication with DPP4i. A 60-year-old man with type II diabetes had been treated with the DPP4i linagliptin for 1 year. After the right forearm experienced a thermal burn, blisters developed around the burned area and gradually spread over the whole body with the production of autoantibodies targeting the non-NC16A domain of BP180. The diagnosis of BP was confirmed by immunohistopathological examination. Upon withdrawal of linagliptin and treatment with topical steroid and minocycline, complete remission was achieved after 4 months. Previously, 13 cases of BP that developed after thermal burns have been reported, and our case shared some of the clinical features of these thermal burn-induced BP cases. Interestingly, the present case also showed the typical clinical, histopathological, and immunological features of the non-inflammatory type of DPP4i-associated BP (DPP4i-BP). Although the pathogenesis of BP remains uncertain, the present case suggests that DPP4i may trigger the onset of BP similarly to a thermal burn. In addition, the clinical and histopathological features of DPP4i-BP may be distinct from other types of BP.

Bullous pemphigoid associated with dipeptidyl peptidase-4 inhibitors: A report of five cases

Bullous pemphigoid (BP) is an autoimmune blistering skin disorder. Recently, BP induced by dipeptidyl peptidase-4 (DPP-4) inhibitors has been a concern. Although DPP-4 inhibitors are commonly used in the Asian population because of their safety and efficacy, BP associated with DPP-4 inhibitors is sometimes seen in clinical settings. Here, we report five Japanese cases of BP associated with the agents. In the present cases, BP occurred in older adults using four different DPP-4 inhibitors, which showed various clinical manifestations in terms of latency period for BP, sex, glycemic control and diabetes duration. Withdrawal of DPP-4 inhibitors was effective in improving BP, and achieved remission even in cases requiring oral steroid administration and intravenous immunoglobulin therapy. Clinicians should note the importance of early diagnosis of this clinical condition and initiate prompt withdrawal of DPP-4 inhibitors.

BP180 Is Critical in the Autoimmunity of Bullous Pemphigoid

Bullous pemphigoid (BP) is by far the most common autoimmune blistering dermatosis that mainly occurs in the elderly. The BP180 is a transmembrane glycoprotein, which is highly immunodominant in BP. The structure and location of BP180 indicate that it is a significant autoantigen and plays a key role in blister formation. Autoantibodies from BP patients react with BP180, which leads to its degradation and this has been regarded as the central event in BP pathogenesis. The consequent blister formation involves the activation of complement-dependent or -independent signals, as well as inflammatory pathways induced by BP180/anti-BP180 autoantibody interaction. As a multi-epitope molecule, BP180 can cause dermal-epidermal separation via combining each epitope with specific immunoglobulin, which also facilitates blister formation. In addition, some inflammatory factors can directly deplete BP180, thereby leading to fragility of the dermal-epidermal junction and blister formation. This review summarizes recent investigations on the role of BP180 in BP pathogenesis to determine the potential targets for the treatment of patients with BP.

Autoantibodies of non-inflammatory bullous pemphigoid hardly deplete type XVII collagen of keratinocytes

Type XVII collagen (COL17) and the non-collagenous 16A (NC16A) domain is regarded as the major pathogenic domains for bullous pemphigoid (BP). Some patients with BP have autoantibodies against parts of COL17 outside the NC16A domain (hereinafter the non-NC16A domain) and show less inflammatory manifestations. There were no significant differences in titres and IgG subclasses between NC16A-BP and non-NC16A-BP as determined by indirect immunofluorescent microscopy. The neutrophil activation capacities determined by ROS release did not differ between NC16A-BP and non-NC16A-BP. However, NC16A-BP IgG depleted COL17 in a dose-dependent manner. Treatment with NC16A-BP IgG, but not with non-NC16A-BP IgG, significantly decreased the adhesion strength. We speculate that the differences in clinical severity between NC16A-BP and non-NC16A-BP relate to the degree of COL17 depletion.

Bullous Pemphigoid Associated with the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin in a Patient with Liver Cirrhosis Complicated with Rapidly Progressive Hepatocellular Carcinoma

A 78-year-old man presented with cutaneous blisters of the limbs and abdominal distension. He had been treated for various diseases, including liver cirrhosis. He had begun receiving sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, for diabetes mellitus three years before the hospitalization. A skin biopsy demonstrated bullous pemphigoid. Ultrasonography (US) revealed multiple liver tumors, although he had been receiving regular US studies. We stopped sitagliptin and started insulin and corticosteroids. However, his renal dysfunction progressed, and he died 14 days after the hospitalization. We should therefore be careful of various complications, including bullous pemphigoid and progression of tumors, when using DPP-4 inhibitors.