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

Clinical characteristics and outcomes of autoimmune blistering diseases in Japan

Autoimmune blistering diseases (AIBDs), including pemphigoid and pemphigus, are intractable dermatological disorders clinically characterized by blistering and erosion affecting mucosal membranes and the skin. Due to their rarity and the limited coverage for less severe cases under Japanese medical subsidies, comprehensive epidemiological analyses encompassing less severe cases have not been conducted in Japan. In this study, we analyzed the epidemiology of AIBDs in Japan, utilizing data from a Japanese nationwide database. We identified 9796 cases of bullous pemphigoid (BP), 62 cases of epidermolysis bullosa acquisita (EBA), 871 cases of pemphigus vulgaris (PV), and 578 cases of pemphigus foliaceous (PF). BP patients exhibited an older age distribution compared to EBA, PV, and PF, with median ages of 81, 72, 65, and 70 years, respectively. Higher rates of comorbidities such as Alzheimer's disease, spondylopathies, and extrapyramidal and movement disorders were observed only in BP cases, while other neurodegenerative disorders such as polyneuropathies, unspecified dementia, and schizophrenia were frequent in both BP and EBA. Dipeptidyl peptidase-4 inhibitors were more commonly prescribed before the onset of BP and EBA compared to PV and PF. Treatment patterns indicated that PV patients were more frequently administered higher doses of oral corticosteroids compared to other AIBDs. Additionally, aggressive therapies, including steroid pulse, intravenous immunoglobulin, and plasmapheresis therapies, were more frequently applied in PV cases. In-hospital mortality rates were higher in BP and EBA at 8.0% and 11.3%, respectively, compared to PV and PF at 2.8% and 5.9%, respectively. Kaplan-Meier analysis indicated that BP and EBA reached a 5-year in-hospital mortality rate of approximately 0.21 and 0.34, while PV and PF rates were approximately 0.07 and 0.11, respectively. The Cox hazard model revealed that higher age is the risk factor for in-hospital mortality in all diseases. Kaplan-Meier analysis indicated a cumulative steroid cessation probability of 0.25 at 3 years for BP, and at 6 and 5 years for PV and PF, respectively. The Cox hazard model revealed that higher age and lower maximum corticosteroid dose contribute to the steroid cessation probability in BP, PV, and PF. This study provides insights into the epidemiology, treatment patterns, comorbidities, and outcomes of AIBDs in Japan.

Association of Dipeptidiyl Peptidase-4 Inhibitors and Bullose Pemphigoid: A Report of Four Cases

Dipeptidyl-peptidase 4 inhibitors (DPP4i) are commonly used as antidiabetic medications. Although these drugs are generally recognized for their favorable clinical safety profile, emerging evidence points to the potential for adverse events associated with DPP4i. Notably, cases of bullous pemphigoid (BP) linked to DPP4i therapy have recently been documented in the medical literature. This report presents four cases of BP in elderly patients resulting from DPP4i treatment, involving two cases with ligandliptin and two with vildagliptin use. Successful remission was achieved in all cases through discontinuation of the implicated medication and implementation of topical corticosteroid therapy. It is imperative for clinicians to be vigilant about the potential risk of BP development when employing DPP4i drugs, particularly in the context of elderly patients with diabetes.

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.

Glucose as a Potential Key to Fuel Inflammation in Rheumatoid Arthritis

Glucose is the most important source of energy and homeostasis. Recent investigations are clarifying that glucose metabolism might be altered in rheumatoid arthritis (RA), which would play a role in the inflammatory phenotype of rheumatoid synovial fibroblasts. It may also play a role in a variety of autoimmune diseases’ pathophysiology by modulating immune responses and modifying autoantigen expressions. The research into glucose and its metabolism could lead to a better understanding of how carbohydrates contribute to the occurrence and duration of RA and other autoimmune diseases.

Case Report: Appearance of Various Disease-Specific Antibodies After the Onset of Dipeptidyl Peptidase-4 Inhibitor-Associated Bullous Pemphigoid

Bullous pemphigoid (BP) is a rare autoimmune blistering disease, and the prevalence of type 2 diabetes mellitus (T2DM) is relatively high in subjects with BP. It is known that dipeptidyl peptidase-4 inhibitor (DPP-4i), one kind of antidiabetic drugs, can cause BP, although precise mechanism of DPP-4i-related BP remains unclear. In this report, we showed a case with appearance of various disease-specific antibodies after the onset of DPP-4i-related BP. Furthermore, various disease-specific antibodies became positive and showed high titers two years after the onset of DPP-4i-related BP and discontinuation of DPP-4i. These data showed that it is possible for immune tolerance to be broken after the onset of DPP-4i-related BP, and it may be important to check autoimmune antibodies in DPP-4i-related BP subjects even when BP symptoms are improved.

Low levels of soluble DPP4 among Saudis may have constituted a risk factor for MERS endemicity

Most of the cases of Middle East respiratory syndrome coronavirus (MERS-CoV) were reported in Saudi Arabia. Dipeptidyl peptidase-4 (DPP4) was identified as the receptor for the virus. The level of soluble DPP4 (sDPP4) was found to be reduced in MERS-CoV infected patients while high levels of sDPP4 were suggested to be protective against MERS-CoV in animal models. We investigated whether the Saudi population has lower levels of sDPP4 which makes them more susceptible to MERS-CoV infection and, therefore, could explain the larger number of cases from the country. Blood samples were collected from 219 Saudi blood donors and 200 blood donors from other ethnic groups. The plasma level of sDPP4 was measured by ELISA and the following SNPs in the DPP4 gene; rs35128070, rs1861978, rs79700168, and rs17574, were genotyped by TaqMan SNP genotyping assay. The average level of plasma sDDP4 was significantly lower in Saudis than other Arabs and non-Arabs (P value 0.0003 and 0.012, respectively). The genotypes AG of rs35128070 and GT of rs1861978 were significantly associated with lower sDPP4 among Saudis (P value 0.002 for each). While both genotypes AA and AG of rs79700168 and rs17574 were associated with significantly lower average sDPP4 level in Saudis compared to other ethnic groups (P value 0.031 and 0.032, and 0.027 and 0.014, respectively). Herein, we report that the Saudi population has lower levels of plasma sDPP4 than other ethnic groups, which is associated with genetic variants in the DPP4 gene. This may have contributed to increase the susceptibility of the Saudi population to MERS-CoV infection and could be a factor in the long-lasting persistence of the virus in the country.

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.