Dipeptidyl peptidase-4 inhibitors and bullous pemphigoid: A systematic review and adjusted meta-analysis

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.

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.

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.

Prevalence of diabetes mellitus in bullous pemphigoid patients in the absence of dipeptidyl peptidase-4 inhibitors: a systematic review and meta-analysis

Bullous pemphigoid (BP) has been associated with dipeptidyl peptidase-4 inhibitor (DDP-4i) use in patients with diabetes mellitus (DM). The prevalence and association of DM in BP patients independent of DPP-4i use has not been investigated by meta-analysis. To perform a systematic review and meta-analysis on the association between diabetes and bullous pemphigoid. The goal was to determine the prevalence and pooled odds ratio of BP patients with DM in the absence of DDP-4i use compared to the general population prevalence of diabetes mellitus. OVID Medline, EMBASE, Cochrane Central and Web of Science were searched for relevant studies published from inception to April 2020. Case-control, case-series, cohort, and cross-sectional studies that included the association of BP and DM without DDP-4i's, in any language. PRISMA guidelines were followed for data extraction and the Newcastle-Ottawa Scale for risk of bias evaluation. Three reviewers independently performed data extraction. Pooled odds ratio and prevalence were calculated using the random effects model. The odds ratio and prevalence of BP patients with DM. Overall, 8 studies out of 856 identified publications through data base searches were included. The pooled prevalence of diabetes in patients with BP was 20.0% [95% CI 14%-26%; p = 0.00]. Within the comparative non-BP control population, 13% had diabetes. BP patients were more likely to have diabetes compared to a control population without BP [OR 2.10, 95% CI 1.22-3.60; p = 0.01]. This study found that twice the number of BP patients have DM (20%) compared to the general population reported as 10.5%, warranting monitoring of blood glucose levels in BP patients who may have yet undeclared or undiagnosed DM when initiating systemic steroids.

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.

Case Report: Localized bullous pemphigoid induced by local triggers: a case series and a proposal for diagnostic criteria based on a literature review

Introduction

Localized bullous pemphigoid (LBP) is an infrequent bullous pemphigoid (BP) variant restricted to a body region. According to the most compelling evidence, LBP occurs in patients with pre-existent serum antibodies against the basement membrane zone, which occasionally acquire the capacity to induce disease after the influence of different local factors acting as triggers.

Methods

We hereby present a multicenter cohort of 7 patients with LBP developed after local triggers: radiotherapy, thermal burns, surgery, rosacea, edema and a paretic leg. In addition, we conducted a review of the literature, and we propose a set of diagnostic criteria for LBP, also based on our case series and the 2022 BP guidelines from the European Academy of Dermatology and Venereology.

Results

During follow-up, three of the patients from our series evolved to a generalized BP, with only one requiring hospitalization. Our literature search retrieved 47 articles including a total of 108 patients with LBP, with a 63% with a potential local precipitating factor previous to their diagnosis. LBP mostly affected older females, and a subsequent generalized progression occurred in 16.7% of the cases. The most frequently involved areas were the lower limbs. Radiation therapy and surgery were responsible for the inducement of nearly 2 in 3 cases of LBP. We observed a significantly higher risk of generalization in cases where the trigger led to the developing of LBP earlier (p=0.016). Our statistical analysis did not detect any other prognosis factor for generalization when assessing direct immunofluorescence, histological and serological results, or other patient related factors.

Conclusion

LBP should be suspected in patients with recurrent localized bullous eruptions. The presence of a trauma history in the same anatomic area is reported in most cases.

Lisinopril prevents bullous pemphigoid induced by dipeptidyl peptidase 4 inhibitors via the Mas receptor pathway

Recent studies have suggested that dipeptidyl peptidase 4 (DPP4) inhibitors increase the risk of development of bullous pemphigoid (BP), which is the most common autoimmune blistering skin disease; however, the associated mechanisms remain unclear, and thus far, no therapeutic targets responsible for drug-induced BP have been identified. Therefore, we used clinical data mining to identify candidate drugs that can suppress DPP4 inhibitor-associated BP, and we experimentally examined the underlying molecular mechanisms using human peripheral blood mononuclear cells (hPBMCs). A search of the US Food and Drug Administration Adverse Event Reporting System and the IBM^® MarketScan^® Research databases indicated that DPP4 inhibitors increased the risk of BP, and that the concomitant use of lisinopril, an angiotensin-converting enzyme inhibitor, significantly decreased the incidence of BP in patients receiving DPP4 inhibitors. Additionally, in vitro experiments with hPBMCs showed that DPP4 inhibitors upregulated mRNA expression of MMP9 and ACE2, which are responsible for the pathophysiology of BP in monocytes/macrophages. Furthermore, lisinopril and Mas receptor (MasR) inhibitors suppressed DPP4 inhibitor-induced upregulation of MMP9. These findings suggest that the modulation of the renin-angiotensin system, especially the angiotensin1-7/MasR axis, is a therapeutic target in DPP4 inhibitor-associated BP.

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.

Association between sodium-glucose co-transporter 2 inhibitors and risk of bullous pemphigoid in patients with type 2 diabetes: A nationwide population-based cohort study

BACKGROUND

Certain anti-diabetic agents have been linked to the development of bullous pemphigoid (BP). However, the relationship between BP and sodium-glucose co-transporter 2 inhibitors (SGLT2is) remains inconclusive.

OBJECTIVE

To investigate the association between SGLT2i usage and BP.

METHODS

Participants were recruited from the Taiwan National Health Insurance Database between 2007 and 2018. A total of 149,060 patients with diabetes receiving SGLT2i were matched 1:2 with diabetic patients without SGLT2i usage. Factors such as age, sex, duration of diabetes condition, DPP4i usage, insulin usage, and selected comorbidities were included in the multivariate analysis.

RESULTS

Compared with the control, the 2-year-cumulative incidence was significantly low in patients using SGLT2i after adjustment for competing mortality. Patients with diabetes receiving SGLT2i had a low risk (adjusted hazard ratio [HR] 0·56, 95% confidence interval [CI], 0·33-0·96) for BP after adjustment for potential confounders. Age (HR, 1·06), renal disease (HR, 1·79), cerebrovascular disease (HR, 3·23), epilepsy (HR, 3·07), DPP4i users (HR: 2·55), and insulin users (HR: 2·56) were significant risk factors for BP.

CONCLUSIONS

The risk of BP did not increase in patients receiving SGLT2i. Thus, SGLT2i could be a safe choice for patients with diabetes having additional risk factors or a history of BP.

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.

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.

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.

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.

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.

The association between clinical and laboratory findings of bullous pemphigoid and dipeptidyl peptidase-4 inhibitors in the elderly: a retrospective study

Aim

To evaluate the association between the use of dipeptidyl peptidase-4 inhibitors (DPP4I) and clinical and laboratory findings of bullous pemphigoid (BP) in patients treated at the European Reference Network – Skin Reference Centre in Croatia.

Methods

This retrospective study enrolled 82 patients treated for BP at the Department of Dermatovenereology, University Hospital Center Zagreb from January 2015 to December 2019. Clinical features of BP, presence of comorbidities, and laboratory findings of anti-BP antibodies and eosinophilia were analyzed in three groups of BP patients: 1) diabetes mellitus (DM) type II patients treated with DPP4I, 2) DM type II patients not treated with DPP4I, and 3) non-DM type II patients.

Results

The average age and anti-BP180 titer were similar in all three groups. DPP4I group had a slightly lower eosinophil level in both peripheral blood (4.89%) and biopsy specimens (87.5%), but the difference was not significant. The prevalence of inflammatory BP in DPP4I group was 76.5%. DPP4I group had significantly higher percentage of patients with chronic renal failure and dementia (52.9% and 11.8%, respectively) compared with non-DPP4I DM (14.3% and 0%, respectively) and non-DM type II patients (15.7% and 0%, respectively).

Conclusion

BP patients treated with DPP4I and those not treated with DPP4Is did not significantly differ in laboratory findings. However, DPP4I treatment was associated with an inflammatory subtype of BP and a higher prevalence of dementia and chronic renal failure. These findings warrant further research into the association of BP and DM with dementia and chronic renal failure.

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.

Dipeptidyl peptidase-4 inhibitor-associated bullous pemphigoid, likely triggered by scabies, in a hemodialysis patient with human leukocyte antigen-DQB1*03:01

Bullous pemphigoid (BP) is the most common autoimmune subepidermal bullous diseases. Autoantibodies against hemidesmosomal adhesion proteins might be involved in the developing process. BP usually affects the elderly with high mortality whereas the drug-induced BP is often improved and rarely relapses after the withdrawal of the suspected drug. An accumulated evidence suggests that dipeptidyl peptidase-4 inhibitor (DPP-4I), which has been widely used as the antidiabetic drug improves glycemic control with little risk for hypoglycemia, could be an inducer of DPP-4I-associated BP (DPP-4I-BP). While the precise mechanism remains unclear, a unique immunological profile with human leukocyte antigen (HLA)-DQB1*03:01 could be a biomarker of genetic susceptibility to DPP-4I-BP. Here, we encountered an interesting case of DPP-4I-BP with HLA-DQB1*03:01, which was likely triggered by scabies. A 56-year-old Japanese male with type 2 diabetes on hemodialysis was referred to our hospital due to worsened blisters. Prior to his admission, he had been on linagliptin, a DPP-4I, for 5 months. He then suffered from scabies 2 weeks before his admission while the treatment with ivermectin failed to improve his symptom. Based on his clinical symptom, positive for anti-BP180 autoantibody in serum, and the pathological alterations of skin biopsy specimens, he was diagnosed with DPP-4I-BP. Importantly, he also carried an HLA-DQB1*03:01 allele. Oral prednisolone was subsequently administered after the discontinuation of linagliptin, and his symptom gradually disappeared. Given the fact that the DPP-4I-BP could be a life-threating disease, we should be cautious of prescribing DPP-4I in hemodialysis patients, whose immune system could be impaired.

Increased risk of bullous pemphigoid in dipeptidyl peptidase 4 inhibitors: A nationwide, population-based, cohort study in Taiwan

Recent studies revealed the risk of bullous pemphigoid (BP) in patients with diabetes mellitus (DM) taking dipeptidyl peptidase 4 (DPP-4) inhibitors. To clarify the relationship between taking DPP-4 inhibitors and the risk of BP among patients with DM, we conducted a cohort study by using the National Health Insurance Research Database of Taiwan from 1 January 2009 to 31 December 2015. We identified 6340 patients with DM taking DPP-4 inhibitors and 25 360 DM patients who had not taken DPP-4 inhibitors during the 7-year follow-up period. Compared with the non-DPP-4 inhibitor group, patients taking DDP-4 inhibitors had a higher risk of BP (adjusted hazard ratio [aHR], 2.382; 95% confidence interval (CI), 1.163-4.883; P = 0.017]. Among the DPP-4 inhibitors available in Taiwan, vildagliptin showed the highest risk of BP (aHR, 2.849; 95% CI, 1.893-4.215; P < 0.001), followed by saxagliptin (aHR, 2.657; 95% CI, 1.770-3.934; P < 0.001). Subgroup analysis revealed that the higher risk of BP was observed in patients older than 65 years (aHR, 2.403; 95% CI, 1.590-3.627; P < 0.001). This study revealed that treatment with DPP-4 inhibitors, especially vildagliptin, was significantly associated with an increased risk of BP among DM patients.