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.

Association between serum 25-hydroxyvitamin D concentration and severity of first-diagnosed bullous pemphigoid in older adults.

BACKGROUND: Higher vitamin D status has been associated with symptom improvement and decreased risk of various autoimmune disorders. Our objective was to determine whether higher serum 25-hydroxyvitamin D (25OHD) concentration correlated with less severe first-diagnosed bullous pemphigoid (BP) in older inpatients. METHODS: This cross-sectional study was performed from November 2012 to February 2014 among 30 consecutive older inpatients (21 women; mean ± SD, 83 ± 7 years; all Caucasian) with a de novo diagnosis of active BP recruited in the Department of Dermatology of Angers University Hospital, France. The severity of BP was graded clinically on the basis of i) the number of bullae during the first three days of hospitalization (grade 0-4, worse), and ii) the extent of the lesions (grade 0-5, worse). RESULTS: Sixteen participants had ≤ 5 bullae at the time of diagnosis, 8 had 6-20 bullae, 3 had 20-50 bullae, and 3 had >50 bullae. The lesions were spread over 5 cutaneous areas in 5 participants (17%). The median 25OHD concentration was 23 [IQR, 16-42] nmol/L. Serum 25OHD concentration was inversely correlated with the bullae grade (ρ = - 0.38, p = 0.04) and the lesion extension grade (ρ = - 0.50, p = 0.005). CONCLUSIONS: Higher serum 25OHD concentration correlated with less severe BP prior to initiation of treatment among our sample of older inpatients. This result suggests that vitamin D may be involved in the pathophysiology of BP and could serve as prognostic biomarker of BP.

Bullous pemphigoid with dipeptidyl peptidase-4 inhibitors: Clinical features and pathophysiology.

It is strongly suggested that dipeptidyl peptidase-4 inhibitors are associated with increased risk of bullous pemphigoid onset, especially in the elderly. Heightened clinical vigilance for bullous pemphigoid associated with dipeptidyl peptidase-4 inhibitor use is required in daily diabetes care.

A case of bullous pemphigoid exacerbated by irradiation after breast conservative radiotherapy.

We present a case, considered to be a form of the Koebner phenomenon, of bullous pemphigoid that was exacerbated mainly within the irradiated field after breast conservative radiotherapy. In May 2009, a 60-year-old woman was diagnosed with bullous pemphigoid, which was treated with steroid therapy. The following month, she was diagnosed with breast cancer (invasive ductal carcinoma, pT1cN0M0). After breast conservative surgery in December 2009, conservative radiotherapy to the right breast was performed (50 Gy in 25 fractions). Portal skin showed no serious change (up to grade 1 skin erythema) and no bullous neogenesis during conservative radiotherapy. However, 2 months after conservative radiotherapy, new blisters became exacerbated mainly within the irradiated field but also in the area outside the irradiated field. Increasing the dosage of oral steroid and minocycline resulted in relief of bullous pemphigoid, although patchy skin pigmentation remained especially in the irradiated skin.

Complementary peptides against the major epitope in the NC16A domain of BP180 show no specificity as vaccines to bullous pemphigoid.

A stretch of 14 amino acids (542-555) (MCW-1) in the NC16A domain of BP180 has been shown to be an immunogenic and pathogenic epitope for bullous pemphigoid (BP). Therefore, it provides an excellent target for treatment through a complementary peptide approach, which has been established in other autoimmune diseases, including experimental autoimmune myasthenia gravis. We examined two synthetic complementary peptides BP3CP5 and BP5CP3 against this region. These peptides were derived, respectively, by reading the antisense RNA of this region of BP180 in 3'-5' and 5'-3' directions. We found evident complementarities in hydropathic scores between MCW-1 and both complementary peptides. However, by enzyme-linked immunosorbent assay (ELISA), the complementary peptides BP3CP5 and BP5CP3 did not bind to either synthetic peptide BPNP or glutathione-S-transferase (GST) fusion proteins BP180NC16a and GST-BP-1050. BPNP, BP180NC16a and GST-BP-1050 cover the MCW-1 region of BP180 and were used as the natural peptides in this study. In addition, neither BP3CP5 nor BP5CP3 blocked the reaction between BPNP and anti-BPNP antibody, nor did they block immunofluorescent staining of the basement membrane zone by BP sera. Pre-incubation with BP3CP5 and BP5CP3 did not block the binding of BP sera to the BP18NC16a fusion protein in immunoblotting. Furthermore, rabbit antisera raised against BP3CP5 and BP5CP3 did not bind BP sera in ELISA. Pre-incubation with these rabbit antisera did not inhibit or reduce the binding of BP sera to the autoanltigen in either imnmunoblotting or immunofluorescence. Thus, we concluded that complementary peptides against this particular epitope in BP180 NC16A domain showed no specificity as vaccines to BP, although this approach should be tried for other epitopes in various autoimmune bullous diseases.