Rituximab is an effective treatment in patients with pemphigus vulgaris and demonstrates a steroid-sparing effect

Dermatologic adverse events caused by biologic treatments - Pathogenesis and management

Biologics are approved for various dermatologic, allergic, rheumatic, and gastroenterologic inflammatory diseases, as well as for numerous malignancies. The dermatologic adverse events from treatment with biologics may resemble primary inflammatory diseases but differ in pathogenesis. In this article, we describe five different pathogenic mechanisms of dermatologic adverse events. By studying these mechanisms, we hope to gain valuable insights into the pathogenesis of primary inflammatory diseases. In addition, in this article, we provide recommendations for the treatment and management of the dermatological adverse events induced by biologics.

Maintenance treatment of pemphigus with rituximab in real life: A single-center study of 50 patients

BACKGROUND

Following the RITUX 3 therapeutic trial, the French national diagnosis and care protocol (NDCP) for the treatment of pemphigus was updated in 2018. The updated protocol recommends initial treatment with rituximab (RTX) followed by maintenance therapy at 12 and 18 months, and potentially at 6 months where there are risk factors for early relapse. We evaluated these recommendations regarding the management of our own patients.

PATIENTS AND METHODS

Our single-center retrospective study included all patients with pemphigus diagnosed between 01/2015 and 10/2020 and receiving at least one initial infusion of RTX. We collected the following data: type of pemphigus, severity, levels of anti-desmoglein 1 and 3 antibodies at diagnosis and between 2 and 6 months after initial RTX, presence or absence of maintenance therapy and modalities, time to first relapse and duration of associated systemic corticosteroid therapy ≥5 mg/day. Maintenance treatment modalities were as follows: no maintenance treatment, maintenance "on demand" (MT1) i.e. not performed at the rate imposed by the NDCP, and maintenance "according to NDCP" (MT2).

RESULTS

Fifty patients were included (women 54%, median age 58 years, pemphigus vulgaris 68%, moderate to severe 68%). Initial RTX was combined with systemic corticosteroid therapy at 0.5 to 1 mg/kg in 74% of cases. Twenty-seven patients (54%) received no maintenance therapy, 13 were on an MT1 regimen (26%), and 10 were on an MT2 regimen (20%). Median follow-up was 42 months. At the last follow-up, 39 patients (78%) were in complete remission. A total of 25 patients (50%) relapsed: 18/27 (67%) patients without maintenance, 5/13 (38%) with MT1, and 2/10 (20%) with MT2 (p = 0.026). The probability of relapse over time was significantly lower in patients receiving maintenance therapy compared to those who receiving none (p = 0.022). The median time to relapse was 15 months in patients without maintenance, and 30 and 28 in those with maintenance (p = 0.27). The median duration of systemic corticosteroid therapy ≥ 5 mg/day in the no-maintenance group was 10 months, compared to 7 and 9 months respectively in MT1 and MT2 (p = 0.91).

CONCLUSION

Our study confirms the value of RTX maintenance therapy in pemphigus in real life.

Comparison of the Clinical Efficacy of Rituximab Infusion and Dexamethasone-Cyclophosphamide Pulse Therapy and Their Effect on Serum Th1, Th2, and Th17 Cytokines in Pemphigus Vulgaris-A Prospective, Nonrandomized, Comparative Pilot Study

Background

Rituximab infusion and dexamethasone-cyclophosphamide pulse (DCP) are the two most popular regimens used in pemphigus vulgaris (PV) in India.

Objective

The present study compared the clinical efficacy of rituximab and DCP in Indian PV patients and their effects on serum Th1,2, and 17 cytokine levels.

Materials and Methods

A total of 37 patients received DCP (Group A, n = 22) or rituximab (Group B, rheumatoid arthritis protocol (n = 15)) as per patients' preference. They were monitored for clinical response, adverse events (AEs), changes in serum anti-desmoglein-1,3 antibody titers and Th1,2 and 17 cytokine levels at baseline and weeks 20 and 52.

Results

The proportion of patients attaining disease control, remission, and relapse in groups A and B were 82% and 93%; 73% and 93%; and 27% and 50%, respectively, after a median duration of 2 months each for disease control; 4 and 4.5 months for remission; and 5 and 7 months for relapse post remission. The musculoskeletal AEs were the highest in the two groups. Significant and comparable decreases in anti-dsg1 and 3 titers from baseline to weeks 20 and 52 were observed in both groups. Th1 and Th17 cytokine levels decreased, while Th2 cytokines increased post-treatment in both groups. However, no correlation was found between change in body surface area of involvement by PV and anti-dsg titers and cytokine levels before and after therapy in both groups.

Conclusion

Comparable clinical efficacy between DCP and rituximab was observed.

Repurposing of rituximab biosimilars to treat B cell mediated autoimmune diseases

Rituximab, the first monoclonal antibody approved for the treatment of lymphoma, eventually became one of the most popular and versatile drugs ever in terms of clinical application and revenue. Since its patent expiration, and consequently, the loss of exclusivity of the original biologic, its repurposing as an off-label drug has increased dramatically, propelled by the development and commercialization of its many biosimilars. Currently, rituximab is prescribed worldwide to treat a vast range of autoimmune diseases mediated by B cells. Here, we present a comprehensive overview of rituximab repurposing in 115 autoimmune diseases across 17 medical specialties, sourced from over 1530 publications. Our work highlights the extent of its off-label use and clinical benefits, underlining the success of rituximab repurposing for both common and orphan immune-related diseases. We discuss the scientific mechanism associated with its clinical efficacy and provide additional indications for which rituximab could be investigated. Our study presents rituximab as a flagship example of drug repurposing owing to its central role in targeting cluster of differentiate 20 positive (CD20) B cells in 115 autoimmune diseases.

Cross-Reactivity of Antibodies to Rituximab with Other Therapeutic Anti-CD20 Antibodies

One reason for a lack of response to rituximab as well as infusion-related anaphylactic adverse events is the development of antidrug Abs to rituximab. Besides rituximab, a number of other therapeutic Abs targeting CD20 are nowadays available as alternatives. In this study, we investigated the potential cross-reactivity of (human) anti-rituximab Abs to three other anti-CD20 mAbs: ofatumumab, obinutuzumab, and ocrelizumab. In 25 cases of anti-rituximab Abs, cross-reactivity was examined using both direct binding assays and inhibition immunoassays. Although no cross-reactivity was observed to ofatumumab or obinutuzumab, 8 of 25 samples also showed reactivity toward ocrelizumab in at least one of the two assays. Furthermore, in three cases of anti-ocrelizumab Abs, cross-reactivity to rituximab was observed in an inhibition immunoassay, albeit not in a direct binding assay. Our results suggest that obinutuzumab or ofatumumab are safe anti-CD20 alternatives in case of the presence of anti-rituximab Abs. It is advisable to proceed cautiously if switching from rituximab to ocrelizumab (or vice versa) is considered in case these alternatives may not be available.

Rituximab in the Management of Autoimmune Bullous Diseases: A Treatment-Resistant Case Series from a Single Central European Referral Center

Background and Objectives: Rituximab (RTX) has been the predominant treatment for autoimmune bullous diseases (AIBDs). The objective of this research was to assess the advantages and safety characteristics of RTX treatment in individuals with AIBD. This assessment focused on clinical remission and a reduction in glucocorticosteroid usage, its effect on the titers of autoantibodies targeting desmoglein-1 (DSG-1) and desmoglein-3 (DSG-3), and adverse occurrences during a 12-month follow-up period in a dermatology department within a Central European university context. Materials and Methods: Our case series involved eleven patients, including eight patients with pemphigus vulgaris, two with pemphigus foliaceus, and one with epidermolysis bullosa acquisita. They received a 1 g dose of rituximab, repeated over a two-week interval. Results: The reduction in a prednisone-equivalent dosage after 2, 6, and 12 months following the second RTX infusion was 65.05%, 73.99%, and 76.93%, in that order. The titers of antibodies against DSG-1 exhibited reductions of 43.29%, 75.86%, and 54.02% at 2, 6, and 12 months, respectively. By contrast, the antibody concentrations targeting DSG-3 displayed a decrease of 27.88%, 14.48%, and 5.09% at the corresponding time points. Over the course of the 12-month monitoring period, 18.18% of patients experienced disease relapse, while the remaining individuals achieved either complete or partial remission with minimal or no therapy. Adverse effects were noted in 36.36% of the patient population; they were mild, and no serious adverse effects were reported. Conclusions: RTX represents an efficacious and well-tolerated therapeutic option for the management of AIBD and merits consideration in cases of refractory AIBD. However, further research is imperative to delineate the most optimal dosage, dosing frequency, and total quantity of maintenance infusions required. Additionally, there is a compelling need for studies that explore the impact of RTX on individuals with AIBD who do not exhibit a significant reduction in anti-desmoglein autoantibody levels.

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.

Efficacy and safety of Bruton's tyrosine kinase inhibitors in the treatment of pemphigus: A comprehensive literature review and future perspective

Bruton's tyrosine kinase (BTK) is a protein involved in B-cell-receptor signaling and B-cell proliferation. The pathophysiology of several autoimmune diseases, such as pemphigus disorder, relies on the BTK signaling pathway. Therefore, BTK inhibitors were found to be beneficial alternatives to conventional treatmentsThe current study aimed to assess the efficacy and safety of BTK inhibitors in treating pemphigus. A complete search was performed on databases including PubMed/MedLine, Scopus, Web of Science, as well as Google Scholar search engine for studies published by September 20th, 2023. The current review indicates that BTK inhibitors alone or in combination with conventional treatments are promising options in the management of pemphigus. The overall safety profile of BTK inhibitors has been acceptable, and the reported adverse reactions were not severe or life-threatening.

Current biologics in treatment of pemphigus foliaceus: a systematic review

Background

Pemphigus foliaceus (PF) differs from pemphigus vulgaris (PV) in that it affects only the skin and mucous membranes are not involved. Pemphigus is commonly treated with systemic corticosteroids and immunosuppressive agents (ISAs). More recently, biologics have been used. The current literature on biologic therapy often combines treatment of PF with PV, hence it is often difficult for clinicians to isolate the treatment of PF from PV. The purpose of this review was to provide information regarding the use of current biological therapy, specifically in PF.

Materials and methods

A search of PubMed, Embase, and other databases was conducted using keywords pemphigus foliaceus (PF), rituximab (RTX), intravenous immunoglobulin (IVIg), and biologics. Forty-one studies were included in this review, which produced 105 patients with PF, treated with RTX, IVIg, or a combination of both. Eighty-five patients were treated with RTX, eight patients with IVIg, and 12 received both RTX and IVIg.

Results

Most patients in this review had PF that was nonresponsive to conventional immunosuppressive therapies (CIST), and had significant side effects from their use. RTX treatment resulted in complete remission (CR) in 63.2%, a relapse rate of 39.5%, an infection rate of 19.7%, and a mortality rate of 3.9%. Relapse was greater in the lymphoma (LP) protocol than the rheumatoid arthritis (RA) protocol (p<0.0001). IVIg led to CR in 62.5% of patients, with no relapses or infections. Patients receiving both biologics experienced better outcomes when RTX was first administered, then followed by IVIg. Follow-up durations for patients receiving RTX, IVIg, and both were 22.1, 24.8, and 35.7 months, respectively.

Discussion

In pemphigus foliaceus patients nonresponsive to conventional immunosuppressive therapy or in those with significant side effects from CIST, RTX and IVIg appear to be useful agents. Profile of clinical response, as well as relapse, infection, and mortality rates in PF patients treated with RTX were similar to those observed in PV patients. The data suggests that protocols specific for PF may produce better outcomes, less adverse effects, and improved quality of life.

Case Report: Biological treatment of epidermolysis bullosa acquisita: report on four cases and literature review

Epidermolysis bullosa acquisita (EBA) is a chronic, recurrent autoimmune subepidermal bullous disease characterized by the presence of autoantibodies targeting type VII collagen -- basement membrane zone antigen. Standard therapy for EBA includes a combination of systemic corticosteroids and dapsone; however, severe cases may require advanced treatment. The current article reports on four EBA cases in which biologics: infliximab, rituximab (Rtx), and intravenous immunoglobulin (IVIG) were applied. All patients fulfilled the clinical and immunological criteria of EBA: they presented tense blisters healing with atrophic scars on the skin on traumatized areas and in mucous membranes. The diagnosis of EBA was established using numerous techniques: direct and indirect immunofluorescence, salt split skin, ELISA, Fluorescence Overlay Antigen Mapping using Laser Scanning Confocal Microscopy. Since all the patients did not achieve long-term remission on standard treatment (prednisone, dapsone) due to ineffectiveness or side effects of drugs, they eventually were treated with biologics leading to extraordinary skin improvement and stopping the disease for 1-3 years. Biologics in all patients were tolerated very well. No side effects were observed during application as well as multi-month follow-up. The presented cases provide a premise that biological drugs can be a valuable component of EBA therapy.

Janus kinase inhibitors in autoimmune bullous diseases

Autoimmune bullous disease (AIBD) is a severe skin disorder caused by autoantibodies that target intercellular or cell-matrix adhesion proteins. Currently, the preferred treatment for AIBD involves the use of glucocorticoids or traditional immunosuppressants. Additionally, the utilization of biological agents such as rituximab, omalizumab, and dupilumab is on the rise. However, effectively managing AIBD remains a challenge. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway has been implicated in various inflammatory diseases. In recent years, a range of drugs known as JAK inhibitors, which target this pathway, have been developed. Several studies have explored the efficacy and safety of JAK inhibitors for treating AIBD. Consequently, this review begins by examining the role of the JAK/STAT pathway in AIBD, summarizing the application of different JAK inhibitors in AIBD treatment, and emphasizing the importance of disease management in treating AIBD with JAK inhibitors. Furthermore, it highlights the need for a better understanding of the JAK/STAT pathway's role in AIBD, as well as the effectiveness and safety of JAK inhibitors for treating this disease.

Cotrimoxazole as a Preventative Intervention for Pneumocystis Pneumonia in Pemphigus Patients Treated with Rituximab: A Retrospective Study

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is a severe, life-threatening complication in patients treated with rituximab. However, there is no consensus on the primary prophylaxis for it in rituximab-treated pemphigus patients. Therefore, we sought to investigate the prophylactic efficacy and safety profile of cotrimoxazole for reducing the risk of developing PJP in pemphigus patients receiving rituximab.

METHODS

This single-center retrospective study investigated 148 pemphigus patients undergoing a first cycle of rituximab between 2008 and 2021 at a tertiary referral center in northern Taiwan. Patients were divided into the prophylaxis group (N = 113) and the control group (N = 35) according to whether or not cotrimoxazole was administered. The primary outcome was the 1-year incidence of PJP in the two groups, while the secondary outcome was the incidence of cotrimoxazole-related adverse events.

RESULTS

Of the 148 patients enrolled in this study, three patients, all in the control group, developed PJP during the 1-year follow-up. The incidence of PJP (8.6%) in the control group was significantly higher than that in the prophylaxis group (0%) (p = 0.012). The incidence of cotrimoxazole-related adverse events was 2.7%, and none of the cases were associated with life-threatening conditions. In addition, the cumulative prednisolone dose was associated with a trend of a higher risk of PJP (p = 0.0483).

CONCLUSIONS

Prophylactic cotrimoxazole significantly reduces the risk of PJP in a certain high-risk population and has a tolerable safety profile.

B-cell targeted therapy of pemphigus

Pemphigus is an autoimmune disease that causes blistering and erosion of the skin and mucous membranes because of autoantibodies against desmoglein, which plays an important role in adhesion between epidermal keratinocytes. Treatment of pemphigus has long been centered on corticosteroids, and the guidelines for management of pemphigus have recommended high-dose systemic corticosteroids as the first-line treatment. While guideline-based treatment has been shown to be beneficial in patients with pemphigus, it has also become clear that this treatment is accompanied by significant burden and risk. The challenge for future pemphigus treatment is to maximize efficacy while minimizing risk during the course of the disease. In this regard, treatment targeting B cells is expected to become increasingly important as autoreactive B cells in pemphigus patients are thought to play a major role in the production of autoantibodies, which form the basis of the pathogenesis. The recent expansion of insurance coverage to rituximab, a monoclonal antibody against CD20, for refractory pemphigus in the USA, Europe, and Japan has opened up a new era of pemphigus treatment by enabling treatment strategies with drugs targeting B cells in patients. Here, we discuss the current status and future prospects of pemphigus treatment, focusing on rituximab and Bruton's tyrosine kinase inhibitors, which are expected to become essential drugs for pemphigus treatment in the future.

Rituximab therapy for intractable pemphigus: A multicenter, open-label, single-arm, prospective study of 20 Japanese patients

This was a multicenter clinical trial of rituximab, a chimeric monoclonal IgG antibody directed against CD20, for the treatment of refractory pemphigus vulgaris and pemphigus foliaceus. In total, 20 patients were treated with two doses of rituximab (1000 mg; 2 weeks apart) on days 0 and 14. The primary end point was the proportion of patients who achieved complete or partial remission on day 168 following the first rituximab dose. Of the 20 enrolled patients, 11 (55%) and four (20%) achieved complete and partial remission, respectively; therefore, remission was achieved in a total of 15 patients (75.0% [95% confidence interval, 50.9%-91.3%]). It was demonstrated that the remission rate was greater than the prespecified threshold (5%). In addition, a significant improvement in clinical score (Pemphigus Disease Area Index) and decrease in serum anti-desmoglein antibody level were observed over time. Four serious adverse events (heart failure, pneumonia, radial fracture, and osteonecrosis) were recorded in two patients, of which only pneumonia was considered causally related with rituximab. The level of peripheral blood CD19-positive B lymphocytes was decreased on day 28 after rituximab treatment and remained low throughout the study period until day 168. Our results confirm the efficacy and safety of rituximab therapy for refractory pemphigus in Japanese patients.

Clinical severity scores as a guide for prediction of initial treatment responses in pemphigus and pemphigoid patients

Pemphigus and pemphigoid are autoimmune blistering diseases that affect mucosa and skin. Several clinical scoring systems, including the pemphigus disease area index (PDAI) and the bullous pemphigoid disease area index (BPDAI), have been validated for managing disease activity and severity. Current guidelines recommend that treatment response be evaluated with clinical scores and that additional second-line therapies be considered if initial treatment is insufficient for disease control. However, there have been few studies analyzing correlations between PDAI/BPDAI transitions and initial treatment effects. To investigate whether PDAI/BPDAI transitions during the treatment initiation phase correlate with initial treatment responses and whether such information can be used as a guide for necessary additional treatment, we retrospectively analyzed 67 pemphigus patients and 47 pemphigoid patients who received initial treatment at Keio University between 2012 and 2018. The clinical symptoms were evaluated weekly with PDAI/BPDAI. The patients were divided into two groups: in group A, disease was controlled only with oral corticosteroids and immunosuppressants (initial treatment), whereas in group B additional therapies were required due to insufficient responses. In pemphigus, the PDAI ratio of day 7/day 0 was significantly reduced in group A compared to group B (0.548 vs 0.761, P < 0.01) after initial treatment had started. In pemphigoid, the ratios of day 7/day 0 of BPDAI (erosion/blister) and BPDAI (urticaria/erythema) significantly decreased in group A compared to group B (0.565 vs 0.901 and 0.350 vs 0.760, respectively, P < 0.05). Receiver operating characteristic analyses on PDAI, BPDAI (erosion/blister) and BPDAI (urticaria/erythema) revealed that the cut-off values in the ratios of day 7/day 0 were 0.762, 0.675, and 0.568, respectively. Our results suggest that PDAI/BPDAI transitions during the initial phase of the treatments may be useful to predict the outcome of the treatment provided and the necessity of additional therapies to achieve disease control.

Applicability of glucocorticoid toxicity index in pemphigus: Comparison between two groups of rituximab-treated and rituximab-naïve patients

Rituximab (RTX) combined with short-term glucocorticoids (GC) is an effective therapeutic option for pemphigus. The newly developed Glucocorticoid Toxicity Index (GTI) tool provides the possibility to measure GC toxicities over time. To compare 1-year GTI between two groups of RTX-treated and RTX-naïve patients with pemphigus. The responsiveness of the GTI was also investigated. A prospective cohort of 129 adults with newly diagnosed pemphigus was conducted. GC-related toxicities were assessed at 3-month intervals according to Composite and Specific lists of the GTI. Of the patients, 76.7% (n = 99) received RTX. Throughout the time intervals, RTX-treated patients had lower GTI compared to RTX-naïve ones (p = 0.036). The mean GTI at 1-year was 34.3 in the RTX-treated group and 50.8 in the RTX-naïve group (p = 0.04). The most commonly observed GC-related toxicity was neuropsychiatric manifestations for 34% (224 events). The relapse rate of RTX-treated patients (1%) was significantly lower than RTX-naïve patients (10%) (p = 0.037). The GTI showed no correlation with cumulative GC consumption in both groups (p > 0.05, both). Patients treated with GC alone had remarkably higher GTI than patients treated with GC plus RTX. The GTI is an applicable tool to quantitatively capture GC toxicities at the patient level in pemphigus.

Nail Loss in Mild to Moderate Pemphigus Vulgaris

Introduction

Symptoms of pemphigus vulgaris (PV) rarely include nail findings. When ungual involvement does occur, the most common manifestations are paronychia and onychomadesis. Onycholysis is very uncommon, and complete nail loss has not been reported in the literature. Ungual involvement is thought to be closely correlated with disease severity, with only severe PV cases demonstrating nail symptoms.

Case Presentation

We report a case of a 34-year-old female presenting with mild to moderate PV yet severe onycholysis of her first toe leading to secondary nail loss in conjunction with paronychia of her bilateral thumbs. Oral tofacitinib and rituximab infusions led to strikingly rapid improvement in her nail symptoms.

Discussion/Conclusion

This case illustrates the importance of a thorough history and physical exam, as a primary complaint of nail symptoms in these patients may lead to unrecognized PV by even the most skilled practitioners. Tofacitinib and rituximab in combination may rapidly improve nail involvement.

Off-Label Uses of Rituximab in Dermatology

Purpose of Review

Rituximab has transformed the treatment of B-cell malignancies and rheumatoid arthritis in the past 2 decades. More recently, this anti-CD20 monoclonal antibody has seen increasing usage in the field of dermatology. This review highlights the evidence supporting its use in several important dermatologic conditions.

Recent Findings

Key recent findings include the 2018 FDA approval of rituximab for the treatment of moderate-to-severe pemphigus.

Summary

Data from randomized controlled trials have demonstrated the efficacy of rituximab in pemphigus, ANCA-associated vasculitis, and cryoglobulinemic vasculitis. More limited data suggests its use in recalcitrant cases of diseases such as pemphigoid, epidermolysis bullosa acquisita, and dermatomyositis. There is scarce evidence and mixed results for rituximab when studied in cutaneous polyarteritis nodosa and cutaneous lupus erythematosus.

Blasenbildende Autoimmundermatosen – Klinik, Diagnostik und neue Therapieansätze

Diese Arbeit gibt eine Übersicht über die Gruppe blasenbildender Autoimmundermatosen und stellt deren wichtigste Vertreter, das bullöse Pemphigoid, den Pemphigus vulgaris sowie den Pemphigus foliaceus, vor. Die häufigste der insgesamt seltenen blasenbildenden Autoimmundermatosen ist das bullöse Pemphigoid (BP). Es betrifft vor allem Patienten jenseits des 60. Lebensjahrs. Charakterisiert ist es typischerweise durch das Auftreten praller Blasen, die mit einem heftigen Juckreiz einhergehen. Ein längeres, sogenanntes prämonitorisches Stadium ohne Blasenbildung ist nicht ungewöhnlich. Es gibt außerdem Varianten mit anderem Erscheinungsbild wie das lokalisierte BP. Der diagnostische Goldstandard ist die direkte Immunfluoreszenzmikroskopie einer periläsional entnommenen Hautbiopsie, welche lineare Ablagerungen von IgG und C3 an der Basalmembran zeigt. Vervollständigt wird die Diagnostik durch die indirekte Immunfluoreszenzmikroskopie sowie weiterführende ELISA-Untersuchungen, mittels derer zirkulierende Autoantikörper im Patientenserum nachgewiesen werden können. Das wichtigste Zielantigen ist BP180, ein hemidesmosomales, von Keratinozyten exprimiertes Protein. Ergänzend kann eine histopathologische Untersuchung erfolgen, die allerdings nur Hinweise zur Spaltebene und zum (meist Eosinophilen-dominierten) Infiltratmuster geben kann und alleine nicht zur Diagnosestellung ausreicht. Die Pathogenese des BP ist Gegenstand der wissenschaftlichen Diskussion. Medikamente wie Dipeptidylpeptidase-4-Inhibitoren können Auslöser sein; Assoziationen zu neurologischen Erkrankungen finden sich häufig. Entsprechend aktueller Leitlinien wird das BP mit topischen bzw. systemischen Glukokortikoiden ggf. in Kombination mit Doxyzyklin, Dapson oder einem Immunsuppressivum behandelt. Bei Therapieresistenz werden intravenöse Immunglobuline oder der anti-CD-20-Antikörper Rituximab eingesetzt. Aufgrund einer vergleichsweise hohen Mortalität bedingt durch Patientenalter und iatrogener Immunsuppression werden neue Therapieansätze gesucht. Fallserien, Kohortenanalysen und Phase 1-/2-Studien mit anti-IgE-Antikörpern und Inhibitoren der eosinophilen Granulozyten sowie des Komplementsystems zeigen teils vielversprechende Effekte. Die wichtigsten Vertreter der Pemphiguserkrankungen sind der Pemphigus vulgaris (PV), der Pemphigus foliaceus (PF) und der sehr seltene paraneoplastische Pemphigus (PNP). Klinisch präsentiert sich der PV mit meist enoralen Schleimhauterosionen und teilweise zusätzlichen Erosionen an der freien Haut. Der PF manifestiert sich nur an der freien Haut. Wie beim BP wird die Diagnose mittels direkter Immunfluoreszenzmikroskopie gestellt, welche beim PV und PF netzförmige Ablagerungen von IgG und C3 innerhalb der Epidermis zeigt. Die häufigsten Zielantigene sind die Desmogleine 1 und 3. Genetische Prädispositionen für den PV und PF sind bekannt und Grund für eine global unterschiedliche Häufigkeit. Der PNP ist immer mit einer malignen Erkrankung assoziiert und von einem progredienten Verlauf mit hoher Mortalität geprägt. Therapeutisch erfordern die Pemphiguserkankungen oft aggressivere Ansätze als das BP. Neben systemischen Glukokortikoiden und Immunsuppressiva wird für den PV und PF der anti-CD-20-Antikörper Rituximab empfohlen. Neue Therapieansätze sind die Hemmung der Bruton-Tyrosinkinase sowie des neonatalen Fc-Rezeptors (FcRN). In einer Phase 2-Studie zeigte Efgartigimod, ein Antagonist des FcRN, eine hohe Therapieeffektivität für Patienten mit PV und PF.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.

IgG4 Autoantibodies in Organ-Specific Autoimmunopathies: Reviewing Class Switching, Antibody-Producing Cells, and Specific Immunotherapies

Organ-specific autoimmunity is often characterized by autoantibodies targeting proteins expressed in the affected tissue. A subgroup of autoimmunopathies has recently emerged that is characterized by predominant autoantibodies of the IgG4 subclass (IgG4-autoimmune diseases; IgG4-AID). This group includes pemphigus vulgaris, thrombotic thrombocytopenic purpura, subtypes of autoimmune encephalitis, inflammatory neuropathies, myasthenia gravis and membranous nephropathy. Although the associated autoantibodies target specific antigens in different organs and thus cause diverse syndromes and diseases, they share surprising similarities in genetic predisposition, disease mechanisms, clinical course and response to therapies. IgG4-AID appear to be distinct from another group of rare immune diseases associated with IgG4, which are the IgG4-related diseases (IgG4-RLD), such as IgG4-related which have distinct clinical and serological properties and are not characterized by antigen-specific IgG4. Importantly, IgG4-AID differ significantly from diseases associated with IgG1 autoantibodies targeting the same organ. This may be due to the unique functional characteristics of IgG4 autoantibodies (e.g. anti-inflammatory and functionally monovalent) that affect how the antibodies cause disease, and the differential response to immunotherapies of the IgG4 producing B cells/plasmablasts. These clinical and pathophysiological clues give important insight in the immunopathogenesis of IgG4-AID. Understanding IgG4 immunobiology is a key step towards the development of novel, IgG4 specific treatments. In this review we therefore summarize current knowledge on IgG4 regulation, the relevance of class switching in the context of health and disease, describe the cellular mechanisms involved in IgG4 production and provide an overview of treatment responses in IgG4-AID.

Pemphigus and Pemphigoid: From Disease Mechanisms to Druggable Pathways

Pemphigus and pemphigoid are paradigms for understanding the mechanisms of antibody-mediated autoimmune disease in humans. In pemphigus, IgG4-predominant autoantibodies cause intraepidermal blistering by direct interference with desmoglein interactions and subsequent disruption of desmosomes and signaling pathways. In pemphigoid, IgG1, IgG4, and IgE autoantibodies against basement membrane zone antigens directly interfere with hemidesmosomal adhesion, activating complement and Fc receptor‒mediated effector pathways. Unraveling disease mechanisms in pemphigus and pemphigoid has identified numerous opportunities for clinical trials, which hold promise to identify safer and more effective therapies for these potentially life-threatening diseases.

Early rituximab treatment is associated with increased and sustained remission in pemphigus patients: a retrospective cohort of 99 patients

OBJECTIVES

Rituximab is the front-line therapy for pemphigus disease. Although very effective, relapse rates are high. We assessed factors associated with disease remission and early relapse following the first rituximab cycle.

MATERIAL AND METHODS

A single center, retrospective cohort study of patients with pemphigus treated with rituximab (1000 mg days 0,14) at the Autoimmune Bullous Disease Clinic of the Division of Dermatology in Rabin Medical Center, Israel, between January 1, 1995 and March 31, 2020.

RESULTS

The cohort included 99 patients with a median follow-up of 37 months (range 12-155). After a single rituximab cycle, 74 patients (75%) achieved remission. Increased time to rituximab was associated with decreased remission rates (OR, 0.98 per month; 95%CI, 0.97-0.998). Of patients in remission with sufficient follow-up, 15/69 (22%) experienced an early relapse (≤12 months from remission). Prolonged time to rituximab and increased baseline disease severity, were associated with early relapse (OR, 1.02 per month; 95%CI, 1.001-1.04; OR, 1.04 per point; 95%CI, 1.01-1.08, accordingly).

CONCLUSIONS

Initiating rituximab early following diagnosis is recommended. Maintenance rituximab infusions, especially for patients with severe baseline disease, should be further investigated.

Applying Early Intervention Strategies to Autoimmune Skin Diseases. Is the Window of Opportunity Preclinical? A Dermato-Rheumatology Perspective

Many inflammatory skin diseases exhibit a chronic course with unsatisfactory long-term outcomes. Insights into early intervention approaches in other autoimmune contexts could improve the trajectory of lifelong diseases in terms of sustained remission or minimal disease activity, reduced requirement for therapy and medical resource use, and improved QoL. In both rheumatoid arthritis (RA) and psoriatic arthritis (PsA), we have learned that the timing and intensity of early interventions can influence later outcomes. Investigation into early RA, PsA, and systemic lupus erythematosus has shown that the optimal window of opportunity may even extend into asymptomatic preclinical phases of diseases. Notably, early and preclinical diseases may have pathogenic mechanisms and therapeutic targets that differ from those of the established disease. In this paper, we review the literature on these insights and discuss how similar research and therapeutic strategies may be investigated in cutaneous autoimmunity. We highlight the contribution of skin-resident cells to diseases that were previously thought to be initiated in the primary and secondary lymphoid organs of the immune system. We focus on two dermato‒rheumatology conditions-lupus and psoriasis-which share the commonality that effective early cutaneous disease therapy may have far-reaching implications on abrogating potentially severe systemic disease.

Insights into Modern Therapeutic Approaches in Pediatric Acute Leukemias

Pediatric cancers predominantly constitute lymphomas and leukemias. Recently, our knowledge and awareness about genetic diversities, and their consequences in these diseases, have greatly expanded. Modern solutions are focused on mobilizing and impacting a patient’s immune system. Strategies to stimulate the immune system, to prime an antitumor response, are of intense interest. Amid those types of therapies are chimeric antigen receptor T (CAR-T) cells, bispecific antibodies, and antibody–drug conjugates (ADC), which have already been approved in the treatment of acute lymphoblastic leukemia (ALL)/acute myeloid leukemia (AML). In addition, immune checkpoint inhibitors (ICIs), the pattern recognition receptors (PRRs), i.e., NOD-like receptors (NLRs), Toll-like receptors (TLRs), and several kinds of therapy antibodies are well on their way to showing significant benefits for patients with these diseases. This review summarizes the current knowledge of modern methods used in selected pediatric malignancies and presents therapies that may hold promise for the future.

Comparison of rituximab and intravenous immunoglobulin in the treatment of autoimmune bullous diseases: Real-life data from a single centre

BACKGROUND/AIM

Rituximab (RTX) and intravenous human immunoglobulin (IVIG) have been shown to be effective in the treatment of autoimmune bullous diseases (ABD), mainly pemphigus vulgaris (PV). The present study aimed to assess the clinical response of patients with ABD, mainly PV to RTX, IVIG and combined regimen of both. Whether adding IVIG to RTX therapy affects the achievement of complete remission off therapy (CR off), reduces time to CR off, time to steroid cessation, and decreases relapse rate was also investigated.

METHODS

Data of 33 patients with ABD [PV (93.9%)], including clinical response to treatment, steroid cessation time, time to CR off and relapse, were recruited from medical charts.

RESULTS

CR off and relapse rate, mean time to CR off and relapse was 86.7% (n = 13) vs 60.0% (n = 6) and 53.3% (n = 8) vs 40% (n = 4), 12.77 ± 9.30 vs 11.25 ± 13.40 and 24.1 ± 16.7 vs 13.0 ± 3.6 months in RTX and combination group, respectively. Older age (P = .005), younger age at the time of diagnosis (P = .004), lesser disease duration to the initiation of RTX (P = .004), lesser BMI (P = .026) and female gender (P = .037) were associated factors with CR off.

CONCLUSION

Adding IVIG to RTX did not increase CR off rates; it also did not decrease time to CR off, time to steroid cessation, relapse rates and did not increase time to relapse. Patient and disease characteristics, including age, younger age at the time of diagnosis, lesser disease duration before RTX treatment, lesser BMI and female gender, are factors associated with CR off.

Pemphigus-The Crux of Clinics, Research, and Treatment during the COVID-19 Pandemic

Pemphigus is a rare autoimmune disease characterised by the production of pathogenic autoantibodies in response to different desmosome proteins. The pathophysiological process leads to the development of blisters and erosions on mucosal and/or skin surfaces. The classical clinical variants of pemphigus are pemphigus vulgaris and pemphigus foliaceus. A diagnostic delay is very common in pemphigus, especially among patients with mucosal involvement. However, in recent years we have witnessed considerably fewer patients with extensive mucocutaneous manifestations, since patients with oral lesions are referred to dermatologists to start the treatment much sooner than they had been previously. Among non-classical variants of pemphigus, unusual cases with discrepancies between autoantibody profiles and clinics challenge the "desmoglein compensation theory". The identification of several other autoantigens that perform a role in the pathogenesis of different variants of pemphigus will progress immunodermatology towards an approach that will determine personalized pemphigus subtypes for each patient. Comorbidities among patients are primarily associated with the prolonged use of corticosteroids and other immunosuppressive agents. The SARS-CoV-2 pandemic raised concerns regarding the immunosuppressive effects of treatment and the risk of a more complicated COVID-19 infection, as well as on the ability to develop an adequate vaccine response.

Comparison of Guidelines for Management of Pemphigus: a Review of Systemic Corticosteroids, Rituximab, and Other Immunosuppressive Therapies

Pemphigus is a severe autoimmune bullous dermatosis that affects the skin and/or mucosa, and it may be life-threatening without proper treatment. The guidelines and/or consensus statements for treatment vary widely between groups. We selected 6 guidelines and consensus statements established by different associations about the management of pemphigus vulgaris (PV) and/or pemphigus foliaceus (PF) to review, compare, and contrast the similarities and differences of these recommendations and provide optimal management suggestions to physicians. Corticosteroids remain a first-line therapy for pemphigus, but there are many differences in initial dose, tapering schedule, and management of relapse between different guidelines. Rituximab is a monoclonal antibody targeting CD20-positive B lymphocytes that is approved as a first-line therapy in moderate-to-severe pemphigus. Immunosuppressive agents, such as azathioprine (AZA) and mycophenolate mofetil (MMF), are also widely used as corticosteroid-sparing drugs, but the adjuvant applications and dosage regimens of different recommendations are not standardized. We attribute these differences to the clinical scoring adopted, the standards for disease severity evaluation, the publication year of each guideline, and local and regional healthcare differences.

Rituximab versus Mycophenolate Mofetil in Patients with Pemphigus Vulgaris

BACKGROUND

Rituximab and mycophenolate mofetil are used to treat pemphigus vulgaris, but they have not been adequately compared in clinical trials.

METHODS

In a randomized, controlled trial, we assigned patients with moderate-to-severe pemphigus vulgaris in a 1:1 ratio to receive intravenous rituximab (1000 mg on days 1, 15, 168, and 182) or oral mycophenolate mofetil (2 g per day), in addition to an oral glucocorticoid administered on the same tapering schedule in the two groups. The primary end point was sustained complete remission at week 52, defined as the healing of lesions with no new active lesions, as reflected by a Pemphigus Disease Area Index (PDAI) activity score of 0 (on a scale of 0 to 250, with higher scores indicating greater disease severity), for at least 16 weeks without the use of glucocorticoids. Secondary end points were the cumulative dose of glucocorticoids, the number of disease flares, and the change from baseline in the score on the Dermatology Life Quality Index (DLQI; scores range from 0 to 30, with higher scores indicating greater impairment).

RESULTS

Of the 135 patients who underwent randomization, 67 were assigned to receive rituximab and 68 to receive mycophenolate mofetil. The primary outcome was assessed in the modified intention-to-treat population: 62 patients in the rituximab group and 63 in the mycophenolate mofetil group. The median PDAI activity scores at baseline were 22.7 in the rituximab group and 18.3 in the mycophenolate mofetil group. At week 52, sustained complete remission was observed in 25 patients (40%) in the rituximab group and in 6 (10%) in the mycophenolate mofetil group (difference, 31 percentage points; 95% confidence interval [CI], 15 to 45; P<0.001). The mean cumulative glucocorticoid dose during the 52-week treatment period was 3545 mg in the rituximab group and 5140 mg in the mycophenolate mofetil group (difference, -1595 mg; 95% CI, -2838 to -353; P<0.001). There were 6 disease flares in the rituximab group and 44 in the mycophenolate mofetil group (adjusted rate ratio, 0.12; 95% CI, 0.05 to 0.29; P<0.001). The mean change in DLQI score was -8.87 points and -6.00 points, respectively (difference, -2.87 points; 95% CI, -4.58 to -1.17; P = 0.001). Serious adverse events occurred in 15 of 67 patients (22%) in the rituximab group and in 10 of 68 (15%) in the mycophenolate mofetil group.

CONCLUSIONS

Rituximab was superior to mycophenolate mofetil in producing sustained complete remission at 52 weeks in patients with pemphigus vulgaris. Rituximab resulted in a greater reduction in glucocorticoid use than mycophenolate mofetil, but more patients in the rituximab group had serious adverse events. Further trials are needed to determine the comparative efficacy and safety of rituximab and mycophenolate mofetil beyond 52 weeks of treatment. (Funded by F. Hoffmann-La Roche; PEMPHIX ClinicalTrials.gov number, NCT02383589.).

Rituximab Therapy for Treatment of Pemphigus in Southeast Asians

Background

Rituximab provides more effective and less adverse effects than the standard dose of corticosteroids, but evidence on its efficacy and safety in the Thai population is lacking.

Objective

To evaluate the efficacy and safety of rituximab in the treatment of pemphigus and also to determine prognostic factors linked to the treatment outcomes.

Methods

Pemphigus patients who received rituximab from November 2017 to December 2020 were retrospectively reviewed. The outcome was evaluated by using early (end of consolidation phase [ECP]) and late endpoints (complete remission [CR] on/off therapy, immunological remission [IR], and relapse). Adverse events were noted. Prognostic factors associated with remission and relapse were analyzed.

Results

Of 53 pemphigus patients, all attained ECP within 1.61 months. Almost 80% achieved CR on therapy within a median time of 6.36 months, while 33.9% reached CR off therapy in 19.74 months. Nearly half had IR within a median time of 6.88 months. Relapse occurred in 33.3% with a median time of 14 months. In multivariate analysis, receiving rituximab within 12 months of disease duration was more likely to achieve CR off therapy and IR (hazard ratio [HR] 3.79; 95% confidence interval [CI] 1.38, 10.42; P = 0.01 and HR 2.74; 95% CI 1.12, 6.69; P = 0.027, respectively), whereas older patients and positive anti-desmoglein 1 levels at the time of CR were predictive indicators for relapse (HR 1.07; 95% CI 1.01, 1.13; P = 0.036 and HR 4.38; 95% CI 1.24, 15.46; P = 0.022, respectively). The treatment-related adverse effects occurred in 33.9%.

Conclusion

Rituximab is effective and safe in Thai pemphigus patients. Early administration of rituximab was a predictor of clinical and immunological remission. Older age and persistently positive anti-Dsg1 were correlated with disease relapse.

The evolving role of rituximab in the treatment of pemphigus vulgaris: a comprehensive state-of-the-art review

INTRODUCTION

Pemphigus vulgaris (PV) is a life-threatening autoimmune mucocutaneous blistering disease. Systemic corticosteroids (CS), while life-saving, have several serious side effects. To improve treatment and prognosis, recently rituximab (RTX), a chimeric monoclonal antibody against CD20 molecule on B cells, has become popular. This Expert Opinion discusses clinical and scientifically relevant aspects of RTX treating PV.

AREA COVERED

This presentation describes the mechanism of action, clinical efficacy, safety, adverse events, protocols used, and clinical outcomes. Concerns for infection, reactivation of latent or previous infections, and high relapse rate are discussed.

EXPERT OPINION

Use of RTX in PV is still a work in progress. There are many unanswered questions. FDA did not provide a protocol or guidelines. Whenever RTX is used, systemic corticosteroids are simultaneously used, albeit for a shorter duration and lower dose. Used in these doses for these durations they can cause immunosuppression. Would it be more appropriate if instead of 'First Line Therapy' it would be more advisable to use the term 'First Adjunctive Immunosuppressive Agent'?

Estimating the susceptibility to SARS-CoV-2 infection with rituximab use for pemphigus vulgaris

The occurrence of the COVID-19 pandemic has raised new uncertainties for dermatologists and their patients, importantly concerning initiation and continuation of immunosuppressants for dermatological conditions at this time. We review two phase III trials of rituximab, a chimeric CD20 monoclonal antibody, used for the treatment of pemphigus vulgaris. Without specific data studying rituximab use and susceptibility of SARS-CoV-2, we hope to utilize available data in order to assist clinician decision making for rituximab in the context of the pandemic.

Clinical and biological activity of rituximab in the treatment of pemphigus

B-cells are major effector cells in autoimmunity since they differentiate into plasmocytes that produce pathogenic auto-antibody such as anti-desmoglein antibodies in pemphigus patients. Major advances were obtained using whole B-cell depleting therapies including anti-CD20 antibodies in refractory pemphigus patients that lead to rituximab approval in pemphigus patients in EU and USA. This review summarizes the data supporting the efficacy of rituximab in pemphigus and provides an overview of the reported immunological changes underlying its therapeutic action. Short and long-term remission in pemphigus is explained by the removal of autoreactive B-cells involved in the production of pathogenic IgG auto-antibodies and by enhancement of the appearance of regulatory B-cells that could maintain long term immune tolerance.

Factors Associated With Short-term Relapse in Patients With Pemphigus Who Receive Rituximab as First-line Therapy: A Post Hoc Analysis of a Randomized Clinical Trial

Importance

Rituximab and short-term corticosteroid therapy are the criterion standard treatments for patients with newly diagnosed moderate to severe pemphigus.

Objective

To examine factors associated with short-term relapse in patients with pemphigus treated with rituximab.

Design, Setting, and Participants

This post hoc analysis of a randomized clinical trial (Comparison Between Rituximab Treatment and Oral Corticosteroid Treatment in Patients With Pemphigus [RITUX 3]) conducted from January 1, 2010, to December 31, 2015, included patients from 20 dermatology departments of tertiary care centers in France from the RITUX 3 trial and 3 newly diagnosed patients treated according to the trial protocol. Data analysis was performed from February 1 to June 30, 2019.

Exposure

Patients randomly assigned to the rituximab group in the RITUX 3 trial and the 3 additional patients were treated with 1000 mg of intravenous rituximab on days 0 and 14 and 500 mg at months 12 and 18 combined with a short-term prednisone regimen.

Main Outcomes and Measures

Baseline (pretreatment) clinical and biological characteristics (Pemphigus Disease Area Index [PDAI] score, ranging from 0-250 points, with higher values indicating more severe disease) and changes in anti-desmoglein (DSG) 1 and anti-DSG3 values as measured by enzyme-linked immunosorbent assay during the 3 months after rituximab treatment were compared between patients with disease relapse and those who maintained clinical remission during the first 12 months after treatment. The positive and negative predictive values of these factors were calculated.

Results

Among 47 patients (mean [SD] age, 54.3 [17.0] years; 17 [36%] male and 30 [64%] female) included in the study, the mean (SD) baseline PDAI score for patients with relapsing disease was higher than that of the patients with nonrelapsing disease (54 [33] vs 28 [24]; P = .03). At month 3, 7 of 11 patients with relapsing disease (64%) vs 7 of 36 patients with nonrelapsing disease (19%) had persistent anti-DSG1 antibody values of 20 IU/mL or higher and/or anti-DSG3 antibody values of 130 IU/mL or higher (P = .01). A PDAI score of 45 or higher defining severe pemphigus and/or persistent anti-DSG1 antibody values of 20 IU/mL or higher and/or anti-DSG3 antibody values of 130 IU/mL or higher at month 3 provided a positive predictive value of 50% (95% CI, 27%-73%) and a negative predictive value of 94% (95% CI, 73%-100%) for the occurrence of relapse after rituximab.

Conclusions and Relevance

The findings suggest that initial PDAI score and changes in anti-DSG antibody values after the initial cycle of rituximab might help differentiate a subgroup of patients with high risk of relapse who might benefit from maintenance rituximab infusion at month 6 from a subgroup of patients with low risk of relapse who do not need early maintenance therapy.

Trial Registration

NCT00784589.

Rituximab in practice: Clinical evaluation of patients with pemphigus after rituximab administration

Pemphigus Vulgaris (PV) is a rare autoimmune blistering disease, which mainly causes mucosal and/or cutaneous lesions. In June 2018, FDA approved Rituximab (RTX)-a B-cell depleting agent-for the management of patients with moderate-to-severe pemphigus. Although the majority of patients respond well to this drug, some do not reach complete remission with a single cycle of RTX. In this review, following an overview of RTX and its clinical outcomes, we have focused on the possible outcomes after RTX therapy in patients with PV. The response is defined into four main categories; complete responders, partial responders, nonresponders, and paradoxical reactions, based on three possibilities of reaching the consolidation phase after 3 months, reaching remission until 6 months, and the ability of corticosteroid tapering in 6 months after RTX administration. Concerning the safety of RTX, three categories of infusion reactions, short and long-term side effects are discussed. Additionally, we have suggested approaches for the evaluation of clinical and serological responses at different critical time-points, including 1, 2, 3, and 6 months after RTX administration. Finally, available markers to predict the response to RTX and research gaps in the field of RTX therapy have been summarized.

Novel Therapies for Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a severe chronic autoimmune blistering disease that affects the skin and mucous membranes. It is characterized by suprabasal acantholysis due to disruption of desmosomal connections between keratinocytes. Autoantibodies against desmosomal cadherins, desmoglein 3 and 1, have been shown to induce disease. Certain human leukocyte antigen (HLA) types and non-HLA foci confer genetic susceptibility. Until the discovery of corticosteroids in the 1950s, PV was 75% fatal. Since then, multiple PV treatments, such as systemic corticosteroids and adjunctive therapy with immunosuppressive medications (mycophenolate mofetil, azathioprine, cyclophosphamide, cyclosporine, methotrexate, gold, and others) have been introduced; however, none have led to long-term remissions and many have undesired adverse effects. Our growing understanding of the pathophysiologic mechanisms in PV is leading to development of new targeted therapies, such as intravenous immunoglobulin, anti-CD20 monoclonal antibodies, inhibitors of Bruton tyrosine kinase and neonatal Fc receptors, and adoptive cellular transfer, that may result in lasting control of this life-threatening disease.

A retrospective cohort study reporting rituximab treatment for 33 patients with immunobullous disease

BACKGROUND

Autoimmune bullous disorders, encompassing pemphigus and pemphigoid diseases, are associated with significant morbidity and mortality. This is in part due to high cumulative doses of corticosteroids in combination with immunosuppressant agents used in traditional treatment regimes. Rituximab is an antiCD20 monoclonal antibody which can induce complete remission, but it is currently unlicensed in the UK and approved only after other treatments have failed.

METHODS

We report a retrospective cohort study of 33 patients with pemphigus and pemphigoid diseases treated with rituximab from a single tertiary centre from 2013 to 2019.

RESULTS

"Complete remission off therapy" was achieved by 27.3% (n = 9), and a further 27.3% (n = 9) had complete remission on minimal therapy. Twenty-one per cent (n = 7) had "partial remission on minimal therapy"; 9.1% (n = 3) patients were in the "consolidation phase," and 12.1% (n = 4) had a "relapse/flare." A steady reduction in prednisolone doses was observed post-Rituximab infusion. Pre-Rituximab the median dose of prednisolone was 20mg (range 10-35, IQR 25), 15mg (range 9.5-22.5, IQR 13) at 1 month, 9mg (range 5-10, IQR 5) at 6 months, 4mg (range 0-5mg, IQR 5) at 12 months and 0 (0-4.35, IQR 4.25) at 18 months. Twelve per cent (n = 4) of patients had documented infusion reaction symptoms. Twelve per cent (n = 4) had later infective complications.

CONCLUSION

This real clinic data adds to the evidence that Rituximab is a safe and effective treatment for both pemphigus and pemphigoid autoimmune blistering conditions. Significantly, we were able to demonstrate a substantial reduction in corticosteroid dosage in our cohort of patients following rituximab treatment.

The ISCCA flow protocol for the monitoring of anti-CD20 therapies in autoimmune disorders

BACKGROUND

Anti-CD20 monoclonals (MoAbs) are used in a variety of autoimmune disorders. The aim is to eliminate memory B cells sustaining the tissue damage and the production of pathogenic autoantibodies, while preserving naïve cells. The disappearance of memory B cells and the repopulation by naïve cells correlate with good clinical response, while the reappearance of memory B cells and plasmablasts correlates with relapse or resistance to therapy. Anti-CD20 induce extremely low B cell levels, requiring high-resolution techniques. The immune monitoring protocol developed by ISCCA is described and validated, to provide a standardized method for the clinical decision-making process during anti-CD20 therapies in autoimmune diseases.

METHODS

A 10-marker, 8-color staining panel (CD20-V450, CD45-V500c, CD4-FITC + sIgM-FITC, CD38-PE, CD3-PerCP Cy5.5, CD19-PE-Cy7, CD27-APC, CD8-APC H7 + sIgG-APC-H7) is used to identify B cells, plasma cells/blasts, naïve and memory B cells, sIgM+ and sIgG-switched memory B cells, T and NK cells, with high-sensitivity analysis (>10⁶ CD45+ cells).

RESULTS

After an anti-CD20 dose, the B cell level is about zero in most patients. If B cells remain virtually absent (<0.1/μl), subsetting is not reliable nor meaningful. If B cells raise >0.3-0.5/μl, subsetting is possible and informative, acquiring >1.0-1.5 × 10⁶ CD45+ events. Further testings can follow the quality of B cell repopulation. If B cells become detectable (>1/μl), the prevalence of memory B cells indicates non-responsiveness or a possible relapse.

CONCLUSIONS

The ISCCA Protocol is proposed for a standardized prospective monitoring of patients with autoimmune disorders, to assist the safe and rational usage of anti-CD20 therapies.

Pemphigus Vulgaris and Bullous Pemphigoid: Update on Diagnosis and Treatment

Autoimmune bullous disorders are a heterogeneous spectrum of skin disorders characterized by the production of autoantibodies against adhesion molecules of the skin. The 2 major groups of diseases are "pemphigus diseases" and "autoimmune bullous diseases of the pemphigoid type." Pemphigus diseases are a group of autoimmune blistering diseases of the skin and mucous membranes characterized by intraepithelial cleft and acantholysis. The main subtypes of pemphigus include pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus. Diagnosis is based on clinical manifestations and confirmed with histological, immunofluorescence, and serological testing. Recently multivariant enzyme-linked immunosorbent assay systems have been developed as practical screening tools for patients with suspected autoimmune bullous dermatoses. The current first-line treatment of pemphigus is based on systemic corticosteroids that are often combined with immunosuppressive adjuvants, such as azathioprine, mycophenolate mofetil, and the anti-CD20 monoclonal antibody rituximab, usually at initiation of treatment. Rituximab efficacy is higher when it is administered early in the course of the disease. Therefore, it should be used as first-line treatment to improve efficacy and reduce cumulative doses of corticosteroids and their side effects. Treatment of bullous pemphigoid is based on disease extension. Localized and mild forms can be treated with superpotent topical corticosteroids or with nonimmunosuppressive agents. In patients with generalized disease or whose disease is resistant to the treatments described above, systemic corticosteroids are preferred and effective. Adjuvant immunosuppressants are often combined with steroids for their steroid-sparing effect.

Radiation-Associated Pemphigus Vulgaris in a Patient With Preceding Malignancy: Treatment With Rituximab as a Valuable Option

Pemphigus is a chronic autoimmune blistering disorder, characterized by (muco-)cutaneous erosions due to autoantibodies against desmoglein 3 and/or 1. Pemphigus induction might be associated with drugs, malignancy or radiation therapy (RT); the latter being only rarely described. A rigorous literature review revealed around 30 cases of RT-associated pemphigus, which had been primarily treated with topical and/or systemic steroids, in some cases also dapsone or few other immunosuppressive agents were given. The most common underlying cancer type was breast cancer. We here present a 63-year-old male patient, who was pre-treated with adjuvant RT for larynx carcinoma 3 months before admission. He developed extensive cutaneous, ocular, and oral erosions. Despite the clinical picture comparable to a paraneoplastic pemphigus, the diagnosis of pemphigus vulgaris of mucocutaneous type was established based on the direct immunofluorescence, showing positive cell surface IgG and discrete C3 deposits, with matching cell surface IgG pattern on monkey esophagus. Serum autoantibodies to desmoglein 1 and 3 were highly positive. No further autoantibodies were found, thus paraneoplastic pemphigus was excluded. The patient was treated with high dose prednisolone, partially given intravenously up to 2 mg/kg per day, as well as topical disinfectants and class IV steroid cream. To stabilize the disease rituximab 2 × 1,000 mg was given, leading to clinical and serological remission for up to 2 years now. We show that rituximab represents a good treatment option for the frequently treatment-refractory RT-associated pemphigus, a clinically and immunologically specific RT-induced skin disorder, resulting in long-term clinical, and serological remission.

Rituximab: A Review in Pemphigus Vulgaris

Rituximab (MabThera^®, Rituxan^®), a chimeric murine/human anti-CD20 monoclonal antibody administered by intravenous infusion, is indicated for the treatment of moderate to severe pemphigus vulgaris (PV), in combination with a tapering course of corticosteroids. Approval in the EU and USA was based on data for the subset of patients with newly-diagnosed, previously untreated PV participating in the randomized, controlled RITUX 3 study; rituximab plus short-course prednisone resulted in a > 3-fold higher rate of complete remission off prednisone therapy and a > 2-fold decrease in the rate of moderate/severe relapse compared with standard-dose prednisone in this patient subpopulation. In addition, rituximab plus short-term prednisone was steroid-sparing and resulted in fewer patients experiencing grade 3 or 4 corticosteroid-related adverse events compared with standard-dose prednisone. The adverse event profile of rituximab in patients with PV was consistent with that observed for the drug in other approved autoimmune disorders; no new safety concerns were identified. Notwithstanding there is some uncertainty over the optimum dosing schedule to achieve and maintain disease control, rituximab is a highly effective and generally well tolerated, steroid-sparing treatment for moderate to severe PV.