Management of pediatric pemphigus vulgaris with rituximab: A case report and review of the literature

Pemphigus vulgaris (PV), an acquired autoimmune bullous disease, is caused by autoantibodies targeting desmosomal proteins in the skin and mucous membranes. Recent data from the adult PV population supports the use of rituximab, a chimeric anti-CD20 IgG1 antibody, as a primary treatment strategy, but limited data exist regarding treatment in the pediatric population. We report the case of a 13-year-old male with PV treated successfully with systemic corticosteroids and rituximab, and review the literature supporting the treatment of pediatric PV with rituximab.

Burden of pemphigus vulgaris with a particular focus on women: A review

Pemphigus vulgaris is a chronic autoimmune mucocutaneous blistering disorder. Apart from the disease itself, other aspects of patients' life, including psychological, social, and financial, can be affected. Women are particularly more disposed to the impact of the disease due to their physiological characteristics, the specific periods of pregnancy and lactation as well as their social and familial role. In this review, we summarized the burden of pemphigus vulgaris on various aspects of women's lives. It is essential to understand these problems and provide appropriate support for patients with such a burdensome disease.

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.

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.

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 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.

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.

Intralesional injection of biosimilar rituximab in recalcitrant mucocutaneous lesions of patients with pemphigus vulgaris: A pilot study

The efficacy of intravenous rituximab (RTX) in patients with pemphigus have been shown in the previous studies. The study aimed to investigate the effectiveness of intralesional injection of RTX in the healing of pemphigus lesions, with lower doses and probable better safety profile than intravenous RTX. Eleven Pemphigus patients with recalcitrant lesions received two intralesional injections of biosimilar RTX, 5 mg/cm² . During 6 months follow-up, Pemphigus Disease Area Index, the patients' satisfaction, quality of life, the disease activity, the number and size of lesions, the anti-desmoglein (Dsg) 1 and 3 antibodies and the count of CD4+ and CD19+ cells were assessed. All patients were in partial remission on therapy. The absolute count of CD19+ B cells showed a statistically significant decline (P = .006). The percentage of CD4 + T lymphocytes increased 2 weeks after injection and decreased 2 weeks later (P = .01). The average number and size of lesions decreased. The concentration of anti-Dsg 3 antibody decreased insignificantly during the study. The severe pain during the injection was considered as the main complication. At the end of the study, two patients were in complete remission on therapy, and the other nine remained in partial remission on therapy. Few side effects resulting from intralesional injection of RTX and enhanced quality of life of the patients were considered as the valuable achievements of this study. The results showed that although a low dose of RTX leads to a significant decrease of CD19+ B lymphocytes, it did not show parallel clinical effectiveness.

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.

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.