The impact of intravenous immunoglobulin on kidney functions and thromboembolic events in dermatology patients

Although intravenous immunoglobulin (IVIG) treatment is generally well tolerated, some adverse effects, ranging from mild to severe, can occur. Nephrotoxicity and thromboembolism are the significant adverse effects of IVIG. However, data on the frequency of thromboembolism and the impact of continuous treatment on renal functions in dermatology patients is limited. This retrospective study was conducted in a cohort of patients who received at least one high-dose (2 g/kg) IVIG cycle due to different dermatological indications, including pemphigus vulgaris, bullous pemphigoid, Stevens-Johnson syndrome, pyoderma gangrenosum, hidradenitis suppurativa and toxic epidermal necrolysis at a university hospital. Demographic and clinical information, thromboembolic events, and kidney function tests were systematically extracted from patient records. The study included 48 patients who received a total of 196 IVIG cycles with a mean dose of two cycles (range 1-41). A significant difference in renal function was observed between baseline and post-treatment in patients who received three or more IVIG cycles. In comparison, no significant difference was found in those receiving one or two IVIG cycles. Five patients (10.4%) experienced a decline of ≥ 20% in the estimated glomerular filtration rate (eGFR). In multivariate analysis, cumulative IVIG dose emerged as the sole independent predictor for a ≥ 20% decline in eGFR (OR 1.61, 95% CI 1.05-2.46, p = 0.02). Thromboembolism occurred in five patients (10.4%), with three cases arising during the first cycle. Thromboembolism, especially during the initial IVIG cycles, and decline in kidney functions related to cumulative IVIG dose were the common and significant side effects in this cohort of dermatology patients.

Epitomic profiling and functional characteristics of pemphigus vulgaris autoantibody binding to keratinocyte M3 muscarinic acetylcholine receptor

Patients with pemphigus vulgaris (PV) develop IgG autoantibodies (AuAbs) binding to keratinocyte desmogleins (Dsg), acetylcholine (ACh) receptors, mitochondrial proteins, and some other self-antigens. In this study, we identified linear and discontinuous peptide tetrameric epitope segments (ES) of M3 muscarinic ACh receptor (M3AR) targeted by different anti-M3AR AuAbs. As positive controls, we identified Dsg1 and Dsg3 ES targeted by PV sera. Healthy individuals also possessed natural antibodies targeting M3AR, Dsg1 and Dsg3 epitopes that were different from those targeted by AuAbs produced by patients with PV. The two targeted M3AR pentameric ES encompass the 10 amino acids-long epitope LSEPTITFGT included the tetramer TFGT containing Thr235 which is a part of the ACh-binding pocket. Previously, it has been demonstrated that the anti-M3AR AuAb produces an agonist-like effect on downstream signaling, but its long-term effect is receptor desensitization. In this study, we compared the functional consequences of binding anti-M3AR AuAbs that target the ACh-binding pocket with that of AuAbs that target M3AR outside of its ACh-binding pocket. While the former AuAbs induced a very high elevation of phospholipase C, inositol triphosphate and diacylglycerol, which represents an agonist-like effect, the latter AuAbs produced a much weaker signaling response. These results indicate that patients with PV develop two types of anti-M3AR AuAbs. One type attaches to orthosteric, i.e., ACh-binding, site and elicits a strong signaling response comparable to that induced by a full pharmacologic agonist, whereas another type binds to an allosteric site and elicits submaximal signaling response comparable to that induced by a partial (allosteric) agonist.

Clinical Characteristics, Comorbidities, and Treatment in Patients with Pemphigus-A Single-Center Retrospective Study

BACKGROUND/OBJECTIVES

Pemphigus comprises a diverse group of disorders within the autoimmune bullous dermatoses (AIBDs) spectrum. Among these, pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are the most commonly encountered variants. Despite its rarity, this condition can pose a life-threatening risk. We aimed to assess clinical characteristics, comorbidities, medication, as well as the treatment of various types of pemphigus in pemphigus patients.

METHODS

We gathered data from 69 patients treated in the Department of Dermatology in the years 2016-2023. The investigation included sex, age at diagnosis, type of pemphigus, comorbidities and medications, presence of neoplasms and treatment of pemphigus, as well as enzyme-linked immunosorbent assay (ELISA) and direct immunofluorescence (DIF) results. The data were statistically analyzed with the p-value set at 0.05.

RESULTS

The study group comprised 69 patients, including 41 women and 28 men. The mean age at diagnosis was 56.89 years +/- 15.42 years. A total of 79.31% of the patients were diagnosed with PV and the following 26.09% with PF. The most common comorbidities were arterial hypertension, hypercholesterolemia, and diabetes mellitus. The dominant treatment regimen was the systemic use of glucocorticosteroids (GCSs; 90% and 94% of PV and PF patients, respectively). More than half of the patients received at least one GCS-sparing treatment, including dapsone and rituximab. We observed a significantly frequent presence of IgG deposits in DIF in patients with PF (p = 0.0217) and a subsequent correlation between the concurrent presence of IgG deposits in DIF and anti-DSG1 antibodies in ELISA testing (p = 0.0469). The combination of IgG, IgG1, IgG4, and C3 deposits was more often existent in PF patients (p = 0.0054) and the combination of IgG4 and C3 deposits in PV patients (p = 0.0339). We also found a positive correlation between the level of anti-DSG1 antibodies and the age at diagnosis (p = 0.0298).

CONCLUSIONS

Patients with pemphigus are very often diagnosed with significant comorbidities and take diverse medication, which shows that the treatment of pemphigus should follow a multidisciplinary approach. Accurate analysis of the clinical condition of the patients, as well as the results of the ELISA panel or DIF, is crucial for a successful diagnostic and therapeutic process.

Pemphigus relapse: Mechanisms, risk factors, and agents associated with disease recurrence

Pemphigus represents a spectrum of potentially life-threatening autoimmune-mediated skin blistering conditions caused by antibody production against desmoglein 1 and 3 (anti-DSG 1 and 3) in keratinocytes. Greater than 50% of pemphigus patients experience relapse, which complicates long-term medical management, including risks associated with re-treatment and complications such as infection and dehydration. This review aims to elucidate mechanisms, risk factors, and medications associated with pemphigus relapse. Mechanisms of relapse include the persistence of auto-reactive B-cell populations post-treatment and CD20- B-cell populations that reactivate after B-cell depletion therapy. Risk factors for relapse include high body surface area (BSA) of pemphigus involvement, high body mass index, high severity according to the Pemphigus Disease Area Index (PDAI) at onset, treatment delay, and high anti-DSG1 and DSG3 titers post-treatment. Targeted B-cell localization is associated with better clinical outcomes, including less frequent relapses. Rituximab is currently the gold standard of treatment for moderate-severe pemphigus and has relapse rates of 11%-44% in selected studies, with a mean time to relapse of 5.8 months to 36 months following treatment. Relapse rates across lymphoma dosing (375 mg/m2) versus rheumatoid arthritis dosing (1 g dosing weekly) was inconsistent; however, more frequent dosing, earlier treatment, and higher cumulative dosing were associated with lower relapse rates. Alternative agents that have clinical efficacy include corticosteroid monotherapy, mycophenolate mofetil, azathioprine, and intravenous immunoglobulin. Future studies should include head-to-head comparators over long follow-up periods to identify the best treatment agents associated with the least relapse risk.

Effect of opioid receptor antagonist on mitigating tumor necrosis factor-like weak inducer of apoptosis (TWEAK)-induced apoptolysis in pemphigus pathogenesis

Pemphigus is a severe autoimmune blistering disease characterized by acantholysis triggered by autoantibodies against desmoglein 1 and 3 (DSG1/3). Apoptosis plays a pivotal role in facilitating acantholysis, yet the precise underlying mechanism remains obscure. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is known to promote apoptosis and disrupt cell junctions, although its involvement in pemphigus pathogenesis remains ambiguous. Our study observed decreased DSG1/3 expression alongside increased TWEAK/fibroblast growth factor-inducible 14 (Fn14) expression and keratinocyte apoptosis in both lesional and perilesional skin. In vitro experiments revealed that TWEAK-stimulated keratinocytes exhibited enhanced apoptosis, STAT1 phosphorylation, and reduced intercellular DSG1/3 expression. Notably, bulk-RNA sequencing unveiled that CASPASE-3 was responsible for mediating the DSG1/3 depletion, as confirmed by direct interaction with DSG1/3 in a co-immunoprecipitation assay. Naloxone, known for preserving cellular adhesion and preventing cell death, effectively reduced apoptosis and restored DSG1/3 levels in TWEAK-stimulated keratinocytes. The anti-apoptotic properties of naloxone were further validated in a murine pemphigus model. Our findings elucidate that TWEAK facilitates keratinocyte apoptosis by augmenting caspase-3 activity, leading to DSG1/3 depletion and apoptosis in pemphigus. Importantly, naloxone can counter TWEAK-induced apoptosis in pemphigus pathogenesis, offering a potential therapeutic intervention.

Restoring immune tolerance in pemphigus vulgaris

Intravenous immunoglobulin (IVIg), a preparation of polyclonal serum IgG pooled from numerous blood donors, has been used for nearly three decades and is proving to be an efficient treatment for many autoimmune blistering diseases, including pemphigus vulgaris (PV). Despite its widespread use and therapeutic success, its mechanisms of action are not completely understood. Some of its anti-inflammatory and immunomodulatory actions have been studied. In this study, the authors present a twenty-year follow-up of 21 patients with clinical and immunopathological confirmed PV, treated with IVIg as monotherapy, according to an established published protocol. IVIg therapy produced long-term sustained, clinical, serological, and immunopathological remission. For 20 y, these patients received no drugs and experienced no disease. This observation suggests that there was the establishment of immune balance or restoration of immune regulation in these PV patients. Twelve (57%) patients experienced no relapse during follow-up. Six (29%) patients experienced a relapse due to acute stress or post-coronavirus infection and/or vaccination. Reinstitution of IVIg resulted in prompt sustained recovery. Three (14.2%) patients, in clinical and serological remission, died due to unrelated causes. No severe adverse effects from IVIg were documented in all 21 patients. The simultaneous or sequential anti-inflammatory and immunomodulatory effects of IVIg may have influenced the long-term clinical remission observed. This study provides a human prototype to examine the pathophysiology of autoimmunity and a model to study immune regulation and mechanisms that can facilitate restoring immune tolerance.

Intravenous Immunoglobulin for Autoimmune Bullous Diseases: A Case Series from a Central European Referral Center

Background and Objectives: Autoimmune bullous diseases (AIBDs) may be treated with intravenous immunoglobulin (IVIG) infusions. This study aimed to evaluate the benefits and safety profiles of high-dose IVIG therapy in AIBD patients, as determined by clinical remission, the glucocorticosteroid-sparing effect, and adverse events at 12 months follow-up in a Central European university dermatology department setting. Materials and Methods: Our case series included 10 patients: five patients with pemphigus vulgaris, one with pemphigus herpetiformis, one with pemphigus foliaceus, one with bullous pemphigoid, two with epidermolysis bullosa acquisita. They underwent 4-12 monthly cycles of IVIG therapy at a dose of 2 g/kg per cycle. Results: The prednisone dosage reduction after 2, 6, and 12 months following the final IVIG course was 65.45%, 70.91%, and 76.37%, respectively. During the 12-month observation period, disease relapse was observed in 20% of patients, while others achieved complete or partial remission without or with minimal therapy. Side effects were seen in 80% of patients; they were transient and did not necessitate discontinuation of IVIG. Conclusions: IVIG demonstrates effectiveness as a treatment with a favorable safety profile. Nevertheless, its high cost remains a significant drawback, particularly in low-income countries. IVIG should be considered, especially in patients opposed to standard therapies or with contraindications to their use.

A systematic review on efficacy, safety and treatment durability of intravenous immunoglobulin in autoimmune bullous dermatoses: Special focus on indication and combination therapy

Autoimmune bullous diseases (AIBDs) are a group of rare blistering dermatoses of the mucous membrane and/or skin. The efficacy, safety and treatment durability of intravenous immunoglobulin (IVIg) as an alternative treatment should be explored to systematically review the available literature regarding treatment outcomes with IVIg in AIBD patients. The predefined search strategy was incorporated into the following database, MEDLINE/PubMed, Embase, Scopus and Web of Science on 18 July 2022. Sixty studies were enrolled using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The use of IVIg alone or combined with rituximab was reported in 500 patients with pemphigus, 82 patients with bullous pemphigoid, 146 patients with mucous membranes pemphigoid and 19 patients with epidermolysis bullosa acquisita. Disease remission with IVIg therapy and RTX + IVIg combination therapy were recorded as 82.8% and 86.7% in pemphigus, 88.0% and 100% in bullous pemphigoid and 91.3% and 75.0% in mucous membrane pemphigoid, respectively. In epidermolysis bullosa acquisita, treatment with IVIg led to 78.6% disease remission; no data were available regarding the treatment with RTX + IVIg in this group of patients. Among all the included patients, 37.5% experienced at least one IVIg-related side effect; the most common ones were headaches, fever/chills and nausea/vomiting. The use of IVIg with or without rituximab had a favourable clinical response in patients with AIBDs. IVIg has no major influence on the normal immune system, which makes its utilization for patients with AIBDs reasonable.

The Role of Non-Neuronal Acetylcholine in the Autoimmune Blistering Disease Pemphigus Vulgaris

The importance of acetylcholine (ACh) in keratinocyte adhesion and acantholysis has been investigated over the last three decades, particularly in the pathophysiology of autoimmune blistering dermatoses. Pemphigus vulgaris (PV) is an autoimmune blistering skin disease where autoantibody-mediated suprabasilar intraepidermal splitting causes flaccid blisters and non-healing erosions of the oral mucosa and sometimes also of the skin. Historically, acantholysis in PV was thought to be driven by anti-desmoglein (Dsg) antibodies. Herein, we describe the role of autoantibodies against keratinocyte muscarinic and nicotinic acetylcholine receptors, as well as the annexin-like molecule pemphaxin that also binds ACh, in the immunopathogenesis of PV. The identification of targets in this disease is important, as they may lead to novel diagnostic and therapeutic options in the future for this potentially deadly disease.

Mitochondrial Autoantibodies and the Role of Apoptosis in Pemphigus Vulgaris

Pemphigus vulgaris (PV) is an IgG autoantibody-mediated, potentially fatal mucocutaneous disease manifested by progressive non-healing erosions and blisters. Beyond acting to inhibit adhesion molecules, PVIgGs elicit a unique process of programmed cell death and detachment of epidermal keratinocytes termed apoptolysis. Mitochondrial damage by antimitochondrial antibodies (AMA) has proven to be a critical link in this process. AMA act synergistically with other autoantibodies in the pathogenesis of PV. Importantly, absorption of AMA inhibits the ability of PVIgGs to induce blisters. Pharmacologic agents that protect mitochondrial function offer a new targeted approach to treating this severe immunoblistering disease.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Chronic exposure to the anti-M3 muscarinic acetylcholine receptor autoantibody in pemphigus vulgaris contributes to disease pathophysiology

Pemphigus vulgaris (PV) is a potentially lethal autoimmune mucocutaneous blistering disease characterized by binding of IgG autoantibodies (AuAbs) to keratinocytes (KCs). In addition to AuAbs against adhesion molecules desmogleins 1 and 3, PV patients also produce an AuAb against the M3 muscarinic acetylcholine (ACh) receptor (M3AR) that plays an important role in regulation of vital functions of KCs upon binding endogenous ACh. This anti-M3AR AuAb is pathogenic because its adsorption eliminates the acantholytic activity of PV IgG; however, the molecular mechanism of its action is unclear. In the present study, we sought to elucidate the mode of immunopharmacologic action of the anti-M3AR AuAb in PV. Short-term exposures of cultured KCs to PV IgG or the muscarinic agonist muscarine both induced changes in the expression of keratins 5 and 10, consistent with the inhibition of proliferation and upregulated differentiation and in keeping with the biological function of M3AR. In contrast, long-term incubations induced a keratin expression pattern consistent with upregulated proliferation and decreased differentiation, in keeping with the hyperproliferative state of KCs in PV. This change could result from desensitization of the M3AR, representing the net antagonist-like effect of the AuAb. Therefore, chronic exposure of KCs to the anti-M3AR AuAb interrupts the physiological regulation of KCs by endogenous ACh, contributing to the onset of acantholysis. Since cholinergic agents have already demonstrated antiacantholytic activity in a mouse model of PV and in PV patients, our results have translational significance and can guide future development of therapies for PV patients employing cholinergic drugs.

Autoimmune Pemphigus: Latest Advances and Emerging Therapies

Pemphigus represents a group of rare and severe autoimmune intra-epidermal blistering diseases affecting the skin and mucous membranes. These painful and debilitating diseases are driven by the production of autoantibodies that are mainly directed against the desmosomal adhesion proteins, desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1). The search to define underlying triggers for anti-Dsg-antibody production has revealed genetic, environmental, and possible vaccine-driven factors, but our knowledge of the processes underlying disease initiation and pathology remains incomplete. Recent studies point to an important role of T cells in supporting auto-antibody production; yet the involvement of the myeloid compartment remains unexplored. Clinical management of pemphigus is beginning to move away from broad-spectrum immunosuppression and towards B-cell-targeted therapies, which reduce many patients’ symptoms but can have significant side effects. Here, we review the latest developments in our understanding of the predisposing factors/conditions of pemphigus, the underlying pathogenic mechanisms, and new and emerging therapies to treat these devastating diseases.

Transient lymphadenopathy during intravenous immunoglobulin (IVIg) in a patient with pemphigus vulgaris

This is the first case of transient cervical lymphadenopathy as an adverse event during IVIg infusion. IVIg plays a vital role in the treatment of many dermatological conditions and identification of adverse events can facilitate patient counseling.

Intraepithelial autoimmune bullous dermatoses disease activity assessment and therapy

Intraepithelial autoimmune blistering dermatoses are a rare group of skin disorders characterized by disruptions of inter-keratinocyte connections within the epidermis through the action of autoantibodies. The second article in this continuing medical education series presents validated disease activity scoring systems, serologic parameters of disease, treatments, and clinical trials for pemphigus and its subtypes.

Review of indications for immunoglobulin (IG) use: Narrowing the gap between supply and demand

Cellular blood components and plasma-derived medicinal products (PDMPs) are obtained from blood donated by volunteers. In a growing number of countries, in line with World Health Organization advice issued since the mid-1970s, donors are not remunerated. In recent decades, considerable efforts have been made to restrict the indications for labile blood components to those based on evidence, to ensure efficacy and safety. By contrast, the producers of PDMPs have developed pathogen reduction techniques for inactivating the microorganisms in (pooled) plasma, but little attention has been paid to the pertinence of the clinical indications for these products. The use of blood, and of erythrocytes in particular, has declined by almost 40%, but the use of immunoglobulins (IG) tripled between 2004 and 2018, making it necessary to pay donors to obtain sufficient blood to meet the market demand for these products. We analyzed the reasons for this increase to unsustainable levels of use, by investigating (practice) guidelines, recommendations, Cochrane data analyses and systematic reviews for clinical indications for IG over time. We found no new evidence explaining the huge increase up to 2018 or the predicted 5-7% yearly annual increase until 2024. For some former evidence-based indications, biologics have largely replaced IG, but the administration of IG for doubtful indications (up to 40%) has not decreased in recent decades. The main development since 2004 is that IG use in Europe has become market-driven rather than evidence-guided. As transfusion specialists and blood therapists, we must raise the alarm that this situation is likely to continue in the absence of good clinical studies determining the place of IG alongside other treatments, and for as long as market profitability remains the dominant driving force. We discuss here approaches for reversing this trend and moving towards European self-sufficiency through non-remunerated voluntary blood donation.

Autoimmune mucocutaneous blistering diseases in the south of Italy: a 25-year retrospective study on 169 patients

BACKGROUND

Autoimmune mucocutaneous blistering diseases (AMBDs) represent a heterogeneous group of organ-specific and potentially life-threatening diseases. We sought to determine the relationship between clinical remission and therapeutic regimens with clinical type and phenotype of AMBDs, as well as clinical outcomes achieved based on different therapeutic regimens.

METHODS

A retrospective single-center study on 169 AMBDs patients, including pemphigus vulgaris (PV), mucous membrane pemphigoid (MMP), paraneoplastic autoimmune multiorgan syndrome (PAMS), and lichen planus pemphigoides (LPP), was performed from 1994 to 2019 in an oral medicine tertiary center, where we collected sociodemographic data, clinical type and phenotype, prescribed therapies, and related outcomes.

RESULTS

The mean age of AMBDs patients was 55.0 ± 16.4 years. They were followed for a mean of 8.4 ± 5.8 years. The majority of these patients (62.1%) were successfully managed with conventional immunosuppressive therapy (CIST) alone. However, 37.9% of patients required additional biological treatments, either because they were non-responders or developed severe side effects from CIST, or because of the rapid and severe progression of the disease. Overall, complete clinical remission was achieved in 92.3% of patients. A statistically significant difference was noted between the frequency distribution of AMBDs patients among different therapeutic regimens (P = .002), of different clinical phenotype and type of AMBDs patients and clinical remission (P = .012 and P = .005, respectively). No difference was reported regarding clinical outcomes and different therapeutic regimens.

CONCLUSIONS

AMBDs' management may be challenging, nonetheless CIST and biologic regimens introduced, when needed as reliable alternatives to CIST, result in a very high percentage of CCR.

Rationale for including intravenous immunoglobulin in the multidrug protocol of curative treatment of pemphigus vulgaris and development of an assay predicting disease relapse

Analysis of reported outcomes of treatment of pemphigus vulgaris (PV) patients demonstrated that the multidrug approach offers a lower relapse rate compared to the FDA-approved prednisone/rituximab regimen. The multidrug protocol protects keratinocytes from autoantibody attack by systemic corticosteroids and mitochondrion-protecting drugs, selectively eliminates pathogenic autoantibodies by intravenous immunoglobulin (IVIg) and inhibits autoantibody production by cytotoxic immunosuppressors. Therefore, IVIg should be always added to the prednisone/rituximab regimen that does not eliminate circulating autoantibodies. To decrease risk for relapse to a minimum, PV should be maintained in full clinical remission until the critical mass of autoreactive plasma cells dies off. The two major factors that determine patient's risk for a relapse are the composition of the pool of pathogenic autoantibodies and the innate abilities of keratinocytes to sustain an autoantibody attack. As it is currently impossible to evaluate the risk for a relapse, development of a biomarker assay that could do so would be helpful in a long-term management of PV patients. We compared the magnitude of cytochrome c (CytC) release in keratinocytes by serum from PV patients in acute disease stage vs. remission and identified very strong positive correlation with disease severity. PV patients whose serum contained autoantibodies requiring higher amounts of normal IgG to neutralize their ability to release CytC were found to be at a higher risk for disease relapse. However, lack of very strong statistical correlation suggested that CytC is not an ideal biomarker to predict disease relapse, which should prompt a search for alternative candidates.

Pemphigus Vulgaris: Short Time to Relapse in Patients Treated in a Danish Tertiary Referral Center

Pemphigus vulgaris is an autoimmune skin disorder with development of blisters in the skin and mucosa, and it can be a life-threatening disease if not treated. Corticosteroids have been a cornerstone for treating PV, but because of side effects the treatment is combined with other conventional immune modulating drugs and rituximab. The Danish treatment protocol for pemphigus vulgaris is similar to the other Scandinavian countries, and therefore this study is of importance for clinicians in the Scandinavian countries as well as other European countries. We retrospectively identified all patients with Pemphigus vulgaris in our tertiary center over a 7-year period in order to register patient characteristics, treatment, adverse events, comorbidities and the effect of prednisolone dose on remission. In this study 19 patients met the inclusion criteria and remission was seen after a mean of 19.9 weeks, and relapse was seen in 50% after the mean time of 15 weeks. Time to relapse in our study is relatively short compared to studies in which rituximab is used as a first-line drug in treating pemphigus vulgaris.

From bench to bedside: evolving therapeutic targets in autoimmune blistering disease

Autoimmune blistering diseases comprise a group of heterogenous conditions characterized by the loss of tolerance and subsequent development of autoantibodies targeting epidermal and subepidermal adhesion proteins. Blisters and erosions form on the skin and mucous membranes leading to significant morbidity and mortality. Traditional therapies rely on systemic immunosuppression. Advancements in our understanding of the pathophysiology of pemphigus and pemphigoid have led to the development of molecules which target specific pathways involved in induction and perpetuation of disease. In this review, we outline the novel therapeutic strategies including B-cell depletion, T-regulatory cell repletion, cell signalling inhibitors and small molecular inhibitors, inhibitory monoclonal antibodies, as well as complement inhibition. We additionally review their current level of clinical evidence. We lastly review therapeutics targets gleaned from the experimental epidermolysis bullosa acquisita mouse model. These emerging treatments offer an exciting progression from basic science discoveries that have the potential to transform the treatment paradigm in autoimmune blistering diseases.

Synergy among non-desmoglein antibodies contributes to the immunopathology of desmoglein antibody-negative pemphigus vulgaris

Pemphigus vulgaris (PV) is a potentially lethal mucocutaneous blistering disease characterized by IgG autoantibodies (AuAbs) binding to epidermal keratinocytes and inducing this devastating disease. Here, we observed that non-desmoglein (Dsg) AuAbs in the sera of patients with Dsg1/3 AuAb-negative acute PV are pathogenic, because IgGs from these individuals induced skin blistering in neonatal mice caused by suprabasal acantholysis. Serum levels of AuAbs to desmocollin 3 (Dsc3), M3 muscarinic acetylcholine receptor (M3AR), and secretory pathway Ca2+/Mn2+-ATPase isoform 1 (SPCA1) correlated with the disease stage of PV. Moreover, AuAb absorption on recombinant Dsc3, M3AR, or SPCA1 both prevented skin blistering in the passive transfer of AuAbs model of PV in BALB/c mice and significantly decreased the extent of acantholysis in a neonatal mouse skin explant model. Although acantholytic activities of each of these immunoaffinity-purified AuAbs could not induce a PV-like phenotype, their mixture produced a synergistic effect manifested by a positive Nikolskiy sign in the skin of neonatal mice. The downstream signaling of all pathogenic non-Dsg AuAbs involved p38 mitogen-activated protein kinase (MAPK)-mediated phosphorylation and elevation of cytochrome c release and caspase 9 activity. Anti-Dsc3 and anti-SPCA1 AuAbs also activated SRC proto-oncogene, nonreceptor tyrosine kinase (SRC). Of note, although a constellation of non-Dsg AuAbs apparently disrupted epidermal integrity, elimination of a single pathogenic AuAb could prevent keratinocyte detachment and blistering. Therefore, anti-Dsg1/3 AuAb-free PV can be a model for elucidating the roles of non-Dsg antigen-specific AuAbs in the physiological regulation of keratinocyte cell-cell adhesion and blister development.