Serum autoantibody reactivity in bullous pemphigoid is associated with neuropsychiatric disorders and the use of antidiabetics and antipsychotics: a large, prospective cohort study.

BACKGROUND: Bullous pemphigoid (BP), the by far most frequent autoimmune blistering skin disease (AIBD), is immunopathologically characterized by autoantibodies against the two hemidesmosomal proteins BP180 (collagen type XVII) and BP230 (BPAG1 or dystonin). Several comorbidities and potentially disease-inducing medication have been described in BP, yet a systematic analysis of these clinically relevant findings and autoantibody reactivities has not been performed. OBJECTIVE: To determine associations of autoantibody reactivities with comorbidities and concomitant medication. METHODS: In this prospective multicenter study, 499 patients diagnosed with BP in 16 European referral centers were included. The relation between anti-BP180 NC16A and anti-BP230 IgG ELISA values at the time of diagnosis as well as comorbidities and concomitant medication collected by a standardized form were analysed. RESULTS: An association between higher serum anti-BP180 reactivity and neuropsychiatric but not atopic and metabolic disorders was observed as well as with the use of insulin or antipsychotics but not with dipeptidyl peptidase-4 (DPP4) inhibitors, inhibitors of platelet aggregation and L-thyroxine. The use of DPP4 inhibitors was associated with less anti-BP180 and anti-BP230 reactivity compared with BP patients without these drugs. This finding was even more pronounced when compared with diabetic BP patients without DPP4 inhibitors. Associations between anti-BP180 and anti-BP230 reactivities were also found in patients using insulin and antipsychotics, respectively, compared with patients without this medication, but not for the use of inhibitors of platelet aggregation, and L-thyroxine. CONCLUSION: Taken together, these data imply a relation between autoantibody reactivities at the time of diagnosis and both neuropsychiatric comorbidities as well as distinct concomitant medication suggesting a link between the pathological immune mechanisms and clinical conditions that precede the clinically overt AIBD.

Expression of PD-1 and Tim-3 is increased in skin of patients with bullous pemphigoid and pemphigus vulgaris.

BACKGROUND: Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are common autoimmune bullous dermatoses (AIBD) characterized by blisters and erosions. Treatment options are limited and often insufficient. Immune checkpoint receptors play critical roles in immune homoeostasis and self- tolerance. Targeting checkpoint receptors is highly efficient in treatment of various cancers, but often also associated with autoimmune side effects. OBJECTIVES: We therefore aimed to investigate the expression of immune checkpoint receptors in patients with BP and PV. METHODS: We analysed expression of the checkpoint receptors programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin domain 3 (Tim-3) and lymphocyte activation gene 3 (Lag-3) in lesional skin of patients with BP and PV compared to healthy control skin as well as the expression patterns of PD-1 and Tim-3 on various infiltrating immune cells in skin sections of AIBD by immunohistochemistry and immunofluorescence. We also measured serum levels of soluble PD-1, Tim-3 and Lag-3 in AIBD patients by ELISA. RESULTS: We report on increased expression of PD-1 and Tim-3, but not Lag-3, in lesional skin of patients with BP and PV. Investigating the expression pattern of PD-1 and Tim-3 on different cutaneous immune cells, we observed significant upregulation of PD-1 predominantly on infiltrating CD8 T cells and upregulation of Tim-3 on CD8 T cells as well as macrophages. CONCLUSIONS: Our results suggest exploring immune checkpoint receptors as novel therapeutic targets using an agonistic approach in autoimmune bullous diseases.

Severe bullous pemphigoid associated with pembrolizumab therapy for metastatic melanoma with complete regression.

Bullous pemphigoid (BP) is considered to be a humorally mediated autoimmune disease, but autoreactive T-cells and T-regulatory cells (Tregs) have also been implicated in this disease. Tregs and the programmed death-1 (PD-1) : programmed death ligand (PD-L) pathway are both critical in terminating immune response, and elimination of either can result in breakdown of tolerance and development of autoimmunity. We report a patient with metastatic malignant melanoma (MM), who underwent pembrolizumab (anti-PD-1) therapy following unsuccessful treatment with ipilimumab [anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4]. The patient developed BP with increasing serum titres of anti-BP180 IgG autoantibodies and increasing disease severity during pembrolizumab therapy. High doses of corticosteroids and methotrexate were needed to control the BP. Following the termination of pembrolizumab therapy, imaging showed complete regression of all metastatic sites. This result may indicate a crucial role for T-cell suppressive activity in controlling and preventing BP.

Epicatechin selectively prevents nitration but not oxidation reactions of peroxynitrite.

The flavanol (-)-epicatechin has been found to protect against damage inflicted by peroxynitrite, an inflammatory intermediate. Here, epicatechin was tested in systems of increasing complexity. The compound efficiently protected against nitration of protein tyrosine residues by peroxynitrite (IC(50) approximately 0.02 mol epicatechin/mol peroxynitrite). However, at epicatechin concentrations completely preventing nitration of tyrosine by peroxynitrite, protection against the oxidative inactivation of glyceraldehyde-3-phosphate dehydrogenase or soybean lipoxygenase-1 was marginal (IC(50) > 1 mol epicatechin/mol peroxynitrite), approximately two orders of magnitude less. Likewise, epicatechin was relatively ineffective against oxidation of thiols in cell lysates, and against the oxidation of 2',7'-dichlorodihydrofluorescein in cultured cells. The activation of the kinases Akt/protein kinase B, ERK1/2 and p38-MAPK by peroxynitrite in murine aorta endothelial cells was not altered by epicatechin, suggesting that activation of these kinases is due to processes other than tyrosine nitration.