Factors Associated With Complete Remission After Rituximab Therapy for Pemphigus

Direct immunofluorescence on plucked hair outer root sheath can predict relapse in pemphigus vulgaris

BACKGROUND

Prospective research is lacking on the utility of plucked hair outer root sheath direct immunofluorescence (ORS DIF) in the prediction of relapse in pemphigus vulgaris (PV) and the correlation of ORS DIF positivity with serum desmoglein antibody titers.

METHODS

We performed a prospective cohort study enrolling 80 PV patients in complete clinical remission at a tertiary care center in North India. Study participants underwent ORS DIF at baseline, which was repeated every 3 months. Skin biopsy DIF was done at study inclusion, repeated at 3 months, and upon clinical relapse. An antidesmoglein antibody titer was assessed concurrently with ORS DIF in a subset of patients. Patients on adjuvant therapy had their adjuvant therapy withdrawn either at the initial visit, at 3 months, or at a 6-month follow-up. Our objectives were to determine the association between positive ORS DIF and clinical relapse, the correlation between positive ORS DIF and skin biopsy DIF, and between positive ORS DIF and positive antidesmoglein antibody titers (when concurrently done).

RESULTS

Twenty-two patients (27.5%) had a clinical relapse. Baseline immunological markers significantly associated with relapse are ORS DIF positivity with IgG (16/36 [45.44%] P = 0.005) and C3 (12/29 [41.37%] P = 0.047) and greater intensity of baseline IgG and C3 positivity in ORS DIF (IgG, P = 0.002; C3, P = 0.033). Notably, a significant correlation was observed between baseline positive ORS DIF and skin biopsy DIF (IgG, ρ = 0.695; C3, ρ = 0.498). Positive ORS DIF strongly correlated with positive anti-Dsg3 antibody titers (φs = 0.815; P < 0.01). Early withdrawal of adjuvant immunosuppressant (within 3 months) (P = 0.007) and positive ORS DIF were also associated with relapse (P = 0.017).

CONCLUSION AND RELEVANCE

ORS DIF is a reliable predictor of PV clinical relapse and demonstrated robust correlations with skin biopsy DIF and antidesmoglein antibody titers. Periodic assessment of ORS DIF aids in determining new-onset positivity that heralds clinical relapse.

Biomaterial engineering strategies for B cell immunity modulations

B cell immunity has a penetrating effect on human health and diseases. Therapeutics aiming to modulate B cell immunity have achieved remarkable success in combating infections, autoimmunity, and malignancies. However, current treatments still face significant limitations in generating effective long-lasting therapeutic B cell responses for many conditions. As the understanding of B cell biology has deepened in recent years, clearer regulation networks for B cell differentiation and antibody production have emerged, presenting opportunities to overcome current difficulties and realize the full therapeutic potential of B cell immunity. Biomaterial platforms have been developed to leverage these emerging concepts to augment therapeutic humoral immunity by facilitating immunogenic reagent trafficking, regulating T cell responses, and modulating the immune microenvironment. Moreover, biomaterial engineering tools have also advanced our understanding of B cell biology, further expediting the development of novel therapeutics. In this review, we will introduce the general concept of B cell immunobiology and highlight key biomaterial engineering strategies in the areas including B cell targeted antigen delivery, sustained B cell antigen delivery, antigen engineering, T cell help optimization, and B cell suppression. We will also discuss our perspective on future biomaterial engineering opportunities to leverage humoral immunity for therapeutics.

Involvement of palms and soles in patients with autoimmune bullous diseases: a comparative analysis of a diagnostically relevant localization

Introduction

The involvement of palms and soles is variable among disease entities belonging to autoimmune bullous diseases (AIBD). We present our own clinical-laboratory experience concerning presentations of skin lesions on palms and soles in the pemphigus diseases group, pemphigoid diseases group, epidermolysis bullosa acquisita (EBA), and lichen planus pemphigoides (LPP) and discuss the pertinent literature.

Methods

Lesions on palms and soles were assessed retrospectively on the basis of just photographic archives from the beginning of 2014 to March 2023. We comparatively evaluated 462 Slavic patients with AIBD.

Results

Palmoplantar involvement was observed in only 21 patients with AIBD (12 females and 9 males). There was no statistically significant difference between palmoplantar involvement in the pemphigus diseases group compared to the pemphigoid diseases group and no statistically significant difference between the pemphigus diseases group compared to the subepithelial AIBD.

Discussion

Nevertheless, particularly in LPP and EBA, and occasionally in pemphigus diseases and pemphigoid diseases groups of AIBD, localization on palms and soles may be diagnostically important at the clinical level.

Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus and pemphigoid are two potentially life-threatening groups of autoimmune diseases, characterized by autoantibodies targeting structural components of desmosomes or hemidesmosomes, respectively. Affected patients typically show itchy/painful plaques or blistering skin lesions and/or impairing mucosal blistering and erosions, which may strongly impact their quality of life. Since the milestone work of Walter Lever in 1953, who differentiated these two groups of diseases by histopathological analysis of the level of antibody-mediated skin cleavage, enormous progresses occurred. Achievements made in laboratory diagnostics now allow to identify antigen specific structural proteins of the skin that are targeted by pathogenic autoantibodies. These progresses were accompanied by an increased understanding of the pathogenesis of these diseases thanks to the establishment of animal models reproducing disease and on studies on skin and blood of affected individuals, which have been leading to novel and disease-specific treatments. Yet, given their phenotypical overlap with more common dermatological diseases, correct diagnosis and appropriate treatment are often delayed, in some cases leading to irreversible sequelae, including organ dysfunction (i.e., loss of vision in mucous membrane pemphigoid). Here, we provide a concise overview of the clinical appearance, diagnosis and therapeutic management of pemphigus and pemphigoid diseases.

Pemphigus- und Pemphigoid-Erkrankungen: Klinik, Diagnostik und Therapie: Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus und Pemphigoid sind seltene Autoimmunkrankheiten der Haut mit potenziell lebensbedrohlichem Verlauf. Autoantikörper gegen epidermale und junktionale Strukturproteine (Desmosomen sowie Hemidesmosomen) führen bei Betroffenen typischerweise zu juckenden, schmerzhaften Plaques oder Blasen an der Haut und/oder Blasenbildung und Erosionen der Schleimhäute mit möglicher Einschränkung der Lebensqualität. Seit der bahnbrechenden Arbeit von Walter Lever im Jahr 1953, dem es gelang, mittels histopathologischer Untersuchung diese beiden Krankheitsgruppen anhand des Musters der Antikörper‐vermittelten Blasenbildung zu differenzieren, wurden enorme Fortschritte im Verständnis der Erkrankungen erzielt. Die Errungenschaften in der Labordiagnostik ermöglichten die Identifikation von Zielstrukturen zur präzisen Unterscheidung verschiedener Varianten der bullösen Autoimmunerkrankungen. Diese Fortschritte gingen dank der Entwicklung von Tiermodellen mit einem besseren Verständnis der Pathogenese einher. Außerdem haben Studien an Haut und Blut betroffener Patienten zu neuen und krankheitsspezifischen Behandlungen geführt. Aufgrund ihrer Seltenheit und der klinischen Ähnlichkeit mit anderen dermatologischen Erkrankungen verzögern sich die korrekte Diagnosestellung und die Einleitung einer entsprechenden Therapie häufig, was in einigen Fällen zu irreversiblen Folgeerscheinungen, einschließlich Funktionsstörungen von Organen (zum Beispiel Verlust des Sehvermögens beim Schleimhautpemphigoid) führt. Wir geben hier einen Überblick über das klinische Erscheinungsbild, den Diagnosealgorithmus und das therapeutische Management von Pemphigus‐ und Pemphigoid‐Erkrankungen.

Targeting therapy in pemphigus: Where are we now and where are we going?

Pemphigus is a heterogeneous group of autoimmune skin disorders characterized by blistering of the skin and mucosal membranes, potentially affecting the quality of life if left unchecked. The current mainstay of treatment is systemic corticosteroids and immunosuppressive agents. Nevertheless, long-term use of these drugs can easily cause infections and other life-threatening adverse reactions. Thus, currently, researchers are trying to develop new and safer therapeutic approaches. Specifically, targeted therapies to pathogenic immune pathways have been gradually introduced and used for the treatment of pemphigus or in clinical trials, such as monoclonal anti-CD20 antibody, BAFF inhibitor, BTK inhibitor, CAAR-T therapy, FcRn antagonist, and TNF-α inhibitor. In addition, IL-4Rα antibody, IL-17 blockade, mTOR pathway inhibitor, CTLA-4Ig, and p38 MAPK inhibitors are theoretically promising treatment for pemphigus. Here, we review the research progress on the mechanism of targeted therapies for pemphigus.

Review of an Anti-CD20 Monoclonal Antibody for the Treatment of Autoimmune Diseases of the Skin

Biologic therapies targeting B-cells are emerging as an effective strategy to treat a variety of immune-mediated diseases. One of the most studied B-cell-targeted therapies is rituximab, an anti-CD20 monoclonal antibody that exemplifies B-cell depletion therapy and has served as the prototype for other anti-CD20 monoclonal antibodies and the development of biosimilars. While there are multiple studies on the use of rituximab in dermatology, a comprehensive review of rituximab therapy in autoimmune skin conditions is lacking. In this literature review, we summarize indications, treatment efficacy, and safety of rituximab among common autoimmune diseases of the skin: pemphigus vulgaris, cutaneous lupus erythematous, dermatomyositis, systemic sclerosis, thyroid dermopathy, autoimmune pemphigoid diseases, and cutaneous vasculitis diseases. Existing data on rituximab support the approach of rituximab, biosimilars, and newer B-cell-targeting therapies in immune-mediated cutaneous diseases. Overall, rituximab, which targets CD20, provides an effective alternative or concomitant option to traditional immunosuppressants in the management of various autoimmune diseases of the skin. Further studies are necessary to expand the understanding and possible utility of B-cell-targeted therapies among autoimmune skin diseases.

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.

Evaluation of Clinical Relevance and Biological Effects of Antirituximab Antibodies in Patients With Pemphigus

Importance

The clinical relevance of antirituximab antibodies (ARAs) in patients with pemphigus who are treated with rituximab (RTX) is currently unknown.

Objective

To determine the prevalence of ARAs in patients with pemphigus who are treated with RTX and their association with complete remission (CR) and relapse.

Design, Setting, and Participants

This post hoc analysis of the Ritux3 trial was conducted from January 2010 to December 2015 in 25 dermatology departments in France and included 42 patients with moderate-to-severe pemphigus who were randomized to receive treatment with RTX. Five additional patients were recruited for an ancillary study. The proportions of patients who achieved CR or relapsed after an initial treatment cycle of RTX were compared depending on whether patients had ARAs.

Exposures

Patients were treated with 1000 mg of RTX on days 1 and 15 and 2 maintenance infusions of 500 mg at months 12 and 18.

Main Outcomes and Measures

Rates of relapse and sustained CR at month 36. Levels of ARAs, antidesmoglein 1/3 antibodies, RTX serum concentrations, and peripheral blood CD19+ B-cell frequency were measured.

Results

Of 42 participants with vs without ARAs, the mean (SD) age was 55 (17) years and 56 (17) years, respectively; 25 (59.5%) were women. Antirituximab antibodies were detected in the serum samples of 13 of 42 patients (31%) during the first year. Nine patients who experienced relapse before month 12 were excluded because they received additional infusions and could not be further analyzed. Among the 33 remaining patients, 2 patients (6.1%) experienced relapse after month 12, and 31 (95.9%) maintained a sustained CR until month 36. The rate of sustained CR was not different whether patients had ARAs (11 of 13 [85%]) or not (20 of 20 [100%]) (P = .15). Both groups (ARA+ vs ARA-) also had similar CD19+ B-cell depletion and RTX levels, but patients with ARAs had higher anti-desmoglein 3 antibody (DSG3 Abs) levels compared with those without ARAs (mean [SD], 30.1 [50.9] AU/mL vs 4.0 [4.3] AU/mL; P = .03). The 2 patients with ARAs who experienced relapse after month 12 had an undetectable RTX level, incomplete B-cell depletion, and higher anti-DSG3 Abs level than the 11 patients who maintained a sustained CR with ARAs (RTX mean [SD] concentration, 0 ug/mL vs 12.5 [2.2] ug/mL; P = .03; incomplete B-cell depletion, 2 of 2 vs 4 of 11; P = .19; mean [SD] anti-DSG3 Abs levels, 103.5 [61.5] AU/mL vs 19.5 [11.0] AU/mL; P = .001) or patients without ARAs (mean [SD] RTX concentration, 0 ug/mL vs 13.5 [1.8] ug/mL; P = .02; incomplete B-cell depletion, 2 of 2 vs 5 of 20; P = .09; mean [SD] anti-DSG3 Abs level, 103.5 [61.5] AU/mL vs 4.0 [1.0] AU/mL; P < .001).

Conclusions and Relevance

The results of this cohort study suggest that ARAs are frequently detected in patients with pemphigus who are treated with RTX and generally are not associated with patient outcomes. Only a few patients with the combination of ARAs, low RTX concentration, incomplete B-cell depletion, and persistent serum anti-DSG3 Abs seem at high risk of relapse.

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.

Clinical Effectiveness and Safety of Initial Combination Therapy with Corticosteroids and Rituximab in Bullous Pemphigoid: A Retrospective Cohort Study

BACKGROUND

Rituximab is a potential initial adjuvant therapy for bullous pemphigoid, yet clinical experience is scarce.

OBJECTIVE

We aimed to examine the clinical outcomes and safety of initial combination therapy with systemic corticosteroids and adjuvant rituximab for the treatment of bullous pemphigoid.

METHODS

A retrospective cohort study was performed on 84 patients with bullous pemphigoid, who received systemic corticosteroids with or without initial adjuvant rituximab therapy (defined as rituximab use within 12 weeks after initiation of systemic corticosteroids).

RESULTS

Among the 84 patients included (37 received systemic corticosteroids with rituximab and 47 were treated with systemic corticosteroids without rituximab), the median time to complete remission on minimal therapy or off therapy was 215 days (95% confidence interval 176.9-253.1) in patients receiving rituximab vs 529 days (95% confidence interval 338.6-719.4) in those not receiving rituximab. A Cox regression analysis showed an increased probability of reaching complete remission on minimal therapy or off therapy with the combined therapy (hazard ratio = 2.28 [1.28-4.07], p = 0.005) after age, Bullous Pemphigoid Disease Activity Index score, and underlying diseases were controlled. In multivariate logistic/linear regressions, initial adjuvant rituximab therapy was associated with a higher complete remission rate (odds ratio = 6.63 [2.09-21.03]) and lower cumulative prednisolone (mg)/body weight (kg) (B = -24.86 [-44.06 to -8.29]) within 48 weeks. Risk of hospitalization for infection was not elevated in the group treated with adjuvant rituximab.

CONCLUSIONS

Rituximab use as adjuvant therapy within 12 weeks after initiation of systemic corticosteroids was associated with a faster and higher rate of achieving complete remission on minimal therapy or off therapy, as well as a significant corticosteroid-sparing effect and a comparable safety profile in this retrospective study. Hence, initial combination therapy with corticosteroids and adjuvant rituximab could serve as an effective treatment option for bullous pemphigoid, but this requires confirmation in randomized controlled studies.

Rituximab - Progress but Still Not a Final Resolution for Pemphigus Patients: Clinical Report From a Single Center Study

Pemphigus is a rare autoimmune disease characterized by the production of pathogenic autoantibodies against desmosomal adhesion proteins, desmoglein 1 and 3. The pathophysiological process leads to the development of blisters and erosions on mucosal and/or skin surfaces as the main clinical manifestation of the disease. Rituximab emerged as the first-line therapeutic option for pemphigus due to its ability to induce remission by depleting peripheral B lymphocytes. Our aim was to assess the efficacy of rituximab in the treatment of patients in Croatia. A single-center, retrospective study was conducted on 19 patients treated with rituximab following a rheumatoid arthritis dosing protocol between October 2015 and March 2021, with a mean follow-up of 24.1 months. After the first rituximab cycle, two patients achieved complete remission off therapy (10.5%), and six patients achieved complete remission on minimal therapy (31.6%). Partial remission was observed among ten patients (52.6%). Eight patients (44.4%) relapsed after the first rituximab cycle. The mean relapse time was 21 months. Seven patients received two rituximab cycles, and three patients received three cycles. Overall, 13 out of 19 patients experienced complete remission at some point during the study, while there were no non-responders after the rituximab treatment. No statistically significant associations were observed between age, sex, type of disease involvement and clinical remission, either on or off therapy. A steady decrease in anti-desmoglein 1 and anti-desmoglein 3 levels was measured among all patients following rituximab treatment. One patient experienced a treatment-related adverse event of infectious etiology (cellulitis). One patient died following the first rituximab cycle, with the cause of death likely not to be associated with the treatment. Rituximab is an effective disease-modifying agent in the treatment of pemphigus with the main benefit of reducing corticosteroid exposure and steroid-related side effects among pemphigus patients. However, a feature of rituximab therapy is high relapse rates and the need for repeated treatment cycles to achieve complete remission. Developing an optimal protocol for rituximab treatment and finding suitable markers for predicting relapse will improve the management of pemphigus patients.

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.

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.

Experience of Rituximab Therapy in Pemphigus: A Three-Year Retrospective Study from a Sub-Himalayan State

Background

Pemphigus is a group of auto-immune blistering disorders, characterised clinically by mucocutaneous blisters and erosions and histopathologically by intra-epidermal acantholysis. It was traditionally associated with high morbidity and mortality. The use of rituximab has brought upon a new dawn in the treatment of pemphigus.

Aim

A retrospective analysis to ascertain the efficacy, tolerance, adverse effect profile, remission, and relapse with the use of rituximab.

Material and Methods

A retrospective analysis of all diagnosed pemphigus patients who received rituximab therapy over a period of 3 years was performed. The patient's baseline characteristics, disease duration, clinical presentations, mucosal involvement, disease-severity assessment, and adverse events with rituximab were noted. The outcomes were evaluated based on the definitions of the disease-outcome parameters as early and late endpoints.

Results

Of the 17 pemphigus patients, there were 14 females (82.4%) and three males (17.6%) with a mean age of 35.9 ± 16.5 years (range: 9-65 years). Pemphigus vulgaris (PV) was the predominant type in 11 (64.7%) patients. After rituximab infusion, the 17 patients attained the end of consolidation phase (ECP) within 15 days to 3 months, and the mean duration was 1.24 months. The complete remission (CR on/off) ranged from 0.5 to 35 months, and the mean duration of remission was 21.7 months. Within a median time of 4.2 months, almost 80% patients achieved CR on therapy. Nine (53%) patients were in CR without any therapy till the end of the study period, and eight (47%) were in remission while on minimal therapy.

Conclusion

Rituximab is an efficacious therapeutic agent for pemphigus and is better tolerated and safer to all the previous medications used in the treatment.

Multiple cycles of rituximab therapy for pemphigus: A group of patients with difficult- to-treat disease or a consequence of late rituximab initiation?

Pemphigus is a serious autoimmune disease with few appropriate therapeutic options. Although rituximab (RTX) has recently shown great promise in this regard, the best protocol of its administration is remains to be elucidated. This study aimed to evaluate the patients who need at least 3 cycles of treatment with RTX to identify hard-to-treat patients' characteristics, which might lead to consider more prompt protocols for treatment of them. A retrospective cross-sectional study was conducted on 45 patients with pemphigus vulgaris who received at least 3 cycles of RTX. Their demographic, clinical, and laboratory data as well as details of treatment protocol and final clinical situation of patients were evaluated. Totally, 45 patients (21 men and 24 women) with mean age of 44.33 years were included in this paper. Women were about 8 years older than men (mean age: 48.1 years versus 40.1 years, p: 0.011) and needed RTX approximately 2 years later in their course of disease (gap: 41.04 months vs. 14.85 months, p: 0.003). Buccal, truncal, and scalp regions were the most frequent sites of involvement respectively. A significant decrease in both anti-Dsg1, 3 was seen at last visit compared to baseline. However, the amount of this decrement was not significantly different between them (p: 0.083). Partial remission in 31.11%, complete remission in 24.44%, relapse in 15.56%, partial remission on treatment in 15.56% and complete remission on treatment in 13.33% were seen at the last follow-up session. RTX is an effective medication for PV even in patients with refractory disease and its therapeutic effect is increased with each subsequent cycle. Male gender, severe oral mucosal involvement on disease onset and extensive scalp and truncal lesions as first cutaneous manifestation of disease are more likely to be signs of refractory PV. Hence, it is reasonable to consider more prompt protocols for treatment of these cases. Moreover, late prescription of RTX during the course of disease might play a role in presence of more resistant form of disease.

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.

Temporal outcomes after rituximab therapy for pemphigus vulgaris

Pemphigus vulgaris is an autoimmune blistering disease characterized by autoantibodies that target desmoglein adhesion proteins. Rituximab and corticosteroids are FDA-approved therapies for pemphigus vulgaris. As newer treatments for pemphigus enter clinical trials, analysis of clinical and serologic outcomes after rituximab therapy as a function of time is essential to guide clinical trial design. Here, we report detailed temporal and serological outcomes of rituximab treatment of pemphigus vulgaris. The maximal prevalence of complete remission off oral systemic therapy after a single cycle of rituximab was 32.4% at 12 months, or 43.1% by 36 months including additional rituximab cycles. Using receiver operating characteristic curves to develop prediction models for complete remission after a single cycle of rituximab, >90.7% reduction in average desmoglein 3 ELISA titers from baseline to months 3-9 was 94% sensitive, and an average absolute titer ≤130 RU/mL between months 3-9 was 96% specific, for achievement of complete remission off oral systemic therapy. All patients with negative titers at 6-9 months ultimately achieved complete remission off oral systemic therapy. This dataset of clinical and serological outcomes for pemphigus vulgaris patients after rituximab therapy will facilitate clinical trial planning and also guide clinician and patient expectations after rituximab therapy.

An Updated Review of Pemphigus Diseases

Clinicians may encounter a variety of skin conditions that present with vesiculobullous lesions in their everyday practice. Pemphigus vulgaris, pemphigus foliaceus, IgA pemphigus, and paraneoplastic pemphigus represent the spectrum of autoimmune bullous dermatoses of the pemphigus family. The pemphigus family of diseases is characterized by significant morbidity and mortality. Considering the risks associated with a delayed diagnosis or misdiagnosis and the potential for overlap in clinical features and treatment, evaluation for suspected pemphigus disease often requires thorough clinical assessment and laboratory testing. Diagnosis is focused on individual biopsies for histopathology and direct immunofluorescence. Additional laboratory methods used for diagnosis include indirect immunofluorescence and enzyme-linked immunosorbent assay. Recent advancements, including anti-CD20 therapy, have improved the efficacy and reduced the morbidity of pemphigus treatment. This contribution presents updates on the pathophysiology, clinical features, diagnostic work-up, and medical management of pemphigus. Improved strategies for diagnosis and clinical assessment are reviewed, and newer treatment options are discussed.

On the road to eliminating long-lived plasma cells-"are we there yet?"

Central to protective humoral immunity is the activation of B cells and their terminal differentiation into antibody-secreting plasma cells. Long-lived plasma cells (LLPC) may survive for years to decades. Such long-lived plasma cells are also responsible for producing pathogenic antibodies that cause a variety of challenges such as autoimmunity, allograft rejection, and drug neutralization. Up to now, various therapeutic strategies aimed at durably eliminating pathogenic antibodies have failed, in large part due to their inability to efficiently target LLPCs. Several antibody-based therapies have recently gained regulatory approval or are in clinical phases of development for the treatment of multiple myeloma, a malignancy of plasma cells. We discuss the exciting potential of using these emerging cancer immunotherapies to solve the antibody problem.

Systems Approaches to Unravel T Cell Function and Therapeutic Potential in Autoimmune Disease

Producing Ag-specific immune responses constrained to target tissues or cells that can be engaged or disengaged at will is predicated on understanding the network of genes governing immune cell function, defining the rules underlying Ag specificity, and synthesizing the tools to engineer them. The successes and limitations of chimeric Ag receptor (CAR) T cells emphasize this goal, and advances in high-throughput sequencing, large-scale genomic screens, single-cell profiling, and genetic modification are providing the necessary data to bring it to fruition-including a broader application into the treatment of autoimmune diseases. In this review, we delve into the implementation of these developments, survey the relevant works, and propose a framework for generating the next generation of synthetic T cells informed by the principles learned from these systems approaches.

Biologics in autoimmune bullous diseases: Current scenario

Autoimmune bullous diseases can be intraepidermal (pemphigus group of disorders) or subepidermal (pemphigoid group of disorders). The treatment of these disorders chiefly comprises corticosteroids and immunosuppressant adjuvants like azathioprine and mycophenolate mofetil. Autoantibodies are the main mediators of these diseases. Rituximab, a chimeric anti-CD20 monoclonal antibody targeting B-cells, has emerged as an excellent treatment option for refractory pemphigus vulgaris in the last decade. Since then, many new biologics have been proposed/explored for managing autoimmune bullous diseases. These hold potential for greater efficacy and lesser adverse effects than conventional immunosuppressants. In this review, we discuss the role of various biologics in the treatment of autoimmune bullous diseases, followed by a brief discussion on the drawbacks to their use and new developments in this area.

Long-term experience with rituximab therapy for treatment-resistant moderate-to-severe pemphigus

BACKGROUND

Rituximab appears to be effective for treating pemphigus, although there are limited long-term data.

METHODS

This retrospective single-center study evaluated patients with conventional treatment-resistant pemphigus who received rituximab during September 2010-December 2019. The first rituximab cycle was based on the rheumatoid arthritis protocol in all patients except one patient, and additional single doses (500 mg or 1000 mg) were administered after clinical and/or serological relapse. The consensus definitions were used for complete remission off therapy, complete remission on minimal therapy, and clinical relapse. Serological relapse was defined as a progressive ≥2-fold increase in anti-desmoglein titers (vs. previous the measurement).

RESULTS

The study included 52 patients with pemphigus vulgaris and 1 patient with pemphigus foliaceus. The mean number of infusions was 5 and the average follow-up after the first infusion was 56 months. The average time to clinical and/or serological relapse was 12 months. Complete remission was achieved in 84.9% of patients, including after the first rituximab cycle in 25 patients (47.1%). Two patients died during the follow-up period.

CONCLUSION

Additional rituximab cycles may help achieve and prolong remission in patients with moderate-to-severe pemphigus resistant to conventional therapies. However, prospective trials are needed to identify the optimal dosing protocol.

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'?

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.

Treatment of Pemphigus with Rituximab: Real-Life Experience in a Cohort of 117 Patients in Israel

BACKGROUND

A combined regimen of rituximab with corticosteroids for the treatment of pemphigus was effective in a prospective randomized controlled trial.

OBJECTIVE

To assess real-life response to rituximab in patients with pemphigus.

METHODS

A retrospective cohort of patients with pemphigus treated with ≥1 rituximab cycles (1,000 mg on days 0 and 14). The primary outcome was remission rate after 1 cycle. For efficacy analyses, a minimal 6-month follow-up was required. Adverse events were assessed in all patients.

RESULTS

The cohort included 117 patients for safety analysis, 108 for efficacy analysis (median follow-up of 33 months). All but one received concomitant corticosteroids, a third also received adjuvants. Overall, 80/108 patients (74%) achieved remission after the first rituximab cycle at a median of 5.5 months. Relapses occurred in 39 patients (49%) at a median of 18 months. Repeating treatment in relapsed patients increased remission rates to 75 and 88% after the second and third cycles, respectively. Adverse events were similar to those of previous publications. Two elderly patients died of infections attributable to rituximab combined with high-dose corticosteroids.

CONCLUSION

In a large real-life long-term cohort, rituximab with corticosteroids ± adjuvants induced remission in most patients with pemphigus, with relatively favorable safety. Repeating treatment following relapse or remission failure was beneficial.

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.

Antigen-specific B cell depletion for precision therapy of mucosal pemphigus vulgaris

Desmoglein 3 chimeric autoantibody receptor T cells (DSG3-CAART) expressing the pemphigus vulgaris (PV) autoantigen DSG3 fused to CD137-CD3ζ signaling domains, represent a precision cellular immunotherapy approach for antigen-specific B cell depletion. Here, we present definitive preclinical studies enabling a first-in-human trial of DSG3-CAART for mucosal PV. DSG3-CAART specifically lysed human anti-DSG3 B cells from PV patients and demonstrated activity consistent with a threshold dose in vivo, resulting in decreased target cell burden, decreased serum and tissue-bound autoantibodies, and increased DSG3-CAART engraftment. In a PV active immune model with physiologic anti-DSG3 IgG levels, DSG3-CAART inhibited antibody responses against pathogenic DSG3 epitopes and autoantibody binding to epithelial tissues, leading to clinical and histologic resolution of blisters. DSG3 autoantibodies stimulated DSG3-CAART IFN-γ secretion and homotypic clustering, consistent with an activated phenotype. Toxicology screens using primary human cells and high-throughput membrane proteome arrays did not identify off-target cytotoxic interactions. These preclinical data guided the trial design for DSG3-CAART and may help inform CAART preclinical development for other antibody-mediated diseases.

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.

B-cell targeted therapies in pemphigus

Pemphigus is a rare autoimmune disease of the skin, characterized by autoantibodies targeting adhesion proteins of the epidermis, in particular desmoglein 3 and desmoglein 1, that cause the loss of cell-cell adhesion and the formation of intraepidermal blisters. Given that these autoantibodies are both necessary and sufficient for pemphigus to occur, the goal of pemphigus therapy is the elimination of autoreactive B-cells responsible for autoantibody production. Rituximab, an anti-CD20 monoclonal antibody, was the first targeted B-cell therapy approved for use in pemphigus and is now considered the frontline therapy for new onset disease. One limitation of this treatment is that it targets both autoreactive and non -autoreactive B-cells, which accounts for the increased risk of serious infections in treated patients. In addition, most rituximab-treated patients experience disease relapse, highlighting the need of new therapeutic options. This review provides a concise overview of rituximab use in pemphigus and discusses new B-cell and antibody-directed therapies undergoing investigation in clinical studies.

Treatment of Pemphigus Vulgaris and Foliaceus with Adjuvant Rituximab Compared to Immunosuppression Alone: Real-Life Experience

INTRODUCTION

In a randomized prospective trial, adjuvant rituximab was more efficacious than corticosteroids alone in the treatment of pemphigus; however, real-life data are limited. Rituximab treatment for pemphigus has only recently been introduced to the Israeli health basket. Previously, patients received rituximab if they paid out of pocket or through private insurance, separating patients into 2 treatment groups, mostly based on economic capability.

METHODS

A retrospective cohort study of the 12-month clinical response of pemphigus vulgaris/foliaceus patients. We compared patients after a single cycle (1,000 mg on days 0 and 15 or weekly 375 mg/m2 for 4 weeks) of adjuvant rituximab with systemic corticosteroids ± steroid-sparing agents, to patients who were prescribed rituximab, could not obtain it, and received systemic corticosteroids ± steroid-sparing agents.

RESULTS

Forty-five patients were included (adjuvant rituximab, n = 29; immunosuppression alone, n = 16). At baseline, rituximab patients had a higher mean pemphigus disease area index (PDAI) (p = 0.07) and higher mean daily dosages of prednisone (1.51 vs. 1.16 mg/kg, p = 0.39). All patients but 1 in the rituximab group continued systemic steroids, and 31% in the rituximab group versus 50% in the immunosuppression-alone group received systemic adjuvants. At 12 months, partial or complete remission rates (on or off maximum 40 mg/day prednisone equivalent) were nonsignificantly higher in the rituximab group (62 vs. 50%, p = 0.53); however, patients on rituximab showed faster remissions (3.4 ± 1.9 vs. 5.9 ± 3.6 months; p = 0.03) with a trend for a greater PDAI reduction (p = 0.051). Adverse events were comparable.

CONCLUSIONS

In this real-life study, a single cycle of rituximab achieved more remissions and sooner compared to conventional immunosuppression, but the differences were not significant, probably due to a small sample size and severe baseline disease in the rituximab group. Future real-life studies on larger groups are needed.

Long-term outcomes of rituximab therapy in pemphigus

BACKGROUND

Rituximab induces a rapid remission in most patients with pemphigus.

OBJECTIVE

Our aim was to assess the long-term efficacy of rituximab in this disease.

METHOD

We conducted a retrospective study of 59 patients with pemphigus treated with rituximab and observed over a median period of 104 months.

RESULTS

The rate of complete remission off therapy (CRoff) after the first rituximab cycle was 39%, increasing to 61% with additional rituximab courses. Long-term CRoff was achieved in 27% of patients. The recurrence rate after the first rituximab cycle was 63%, decreasing to approximately 40% with subsequent rituximab cycles. Median time to relapse after the first and subsequent rituximab cycles was 25 months. Renewed rituximab therapy reinduced complete remission in 94% of cases. Baseline anti-desmoglein antibody levels of ≤250 U/mL were significantly associated with the outcome of CRoff. In paired serum samples obtained before the first and six months after the last rituximab therapy, significant reductions of desmoglein-specific autoantibodies were observed. Patients relapsing after a complete remission induced by the first rituximab cycle were more likely to achieve CRoff than patients relapsing after a less favourable outcome and non-responders. There was no significant difference in age, sex, pemphigus subtype, rituximab dosing and disease duration between patients achieving CRoff and those not meeting this end point.

CONCLUSIONS

Lower desmoglein-specific antibody levels at baseline were predictive of CRoff. In patients receiving multiple rituximab cycles, complete remission after the first cycle was associated with a favourable long-term outcome. Repeated rituximab courses were highly effective for relapsed disease and improved the overall outcome.

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.