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

Pemphigus Disease and Area Index: Unmet needs in the real-world management of pemphigus

Over the past few decades, a number of scoring instruments have been developed to assess the severity and activity of autoimmune bullous diseases (AIBDs) (Daneshpazhooh et al., 2019; Nili et al., 2020; Nili et al., 2021; Nili et al., 2022). The Pemphigus Disease Area Index (PDAI), developed by the International Pemphigus Definitions Group, is an easy-to-use, quick, and reliable method for determining pemphigus severity. As a reliable and effective tool in clinical trials, PDAI may also have some limitations and might require some revisions to be used on a daily basis. Here, we propose some recommendations to improve the use of PDAI in the clinical setting.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

Combination therapy for management of pemphigus patients with unexpected therapeutic response to rituximab: A report of five cases

Key Clinical Message

The immunosuppressant agents should be considered earlier in the course of treatment with rituximab, possibly after the unfavorable response at first cycle of treatment, especially in male patients and those with high BMI.

Abstract

Rituximab (RTX) has recently been proposed as an alternative first-line therapy for pemphigus patients. However, there are some rare reports of worsening of pemphigus following RTX therapy in the literature. This study aimed to evaluate the efficacy and safety of using a combination treatment of mycophenolate mofetil or dapsone and methotrexate in case of nonresponse, exacerbation or development of allergic reactions following rituximab therapy in pemphigus patients. In this case series, archive files of pemphigus patient in a tertiary care hospital from 2016 to 2021 who were treated with rituximab were reviewed and those with failure in treatment process including nonresponsiveness, exacerbation or development of allergic reactions to rituximab were identified and assessed. The study includes five patients out of 1245 RTX-treated patients, who did not respond to RTX (one patient) or experienced an exacerbation of disease (two patients) or development of allergic reactions (two patients). Male patients with high BMI (BMI > 25) whose response to rituximab was not good at first cycle and happened to receive rituximab later in the course of disease, had highest number of relapses and benefited the most from this combination immunosuppressive treatment as an alternative for repeating rituximab cycles. The lower risk of relapse and a better chance of remission might indicate the efficacy of adjuvant immunosuppressant therapy in patients with no-response, exacerbation, or allergic reaction to rituximab. These therapeutic effects were better observed in patients who received lower doses of rituximab which could suggest that the immunosuppressant agents should be considered earlier in the course of the disease, possibly after the first failed trial of rituximab therapy.

Adverse outcome and severity of COVID-19 in patients with autoimmune bullous diseases: A historical cohort study

The ongoing COVID-19 pandemic has raised concerns regarding the outcome of this infection in patients with autoimmune bullous dermatoses (AIBDs) due to effect of drugs used to treat these disorders. This investigation was performed from the onset of the pandemic to June 1, 2021. Patients with AIBDs who contracted COVID-19 were evaluated. A generalized linear model was employed to find the predictors of severe COVID-19 among patients with AIBDs. Ninety-three patients with AIBDs with a mean age of 50.3 years were evaluated. The most COVID-19 related symptoms were tiredness (76.3%) myalgia (69%), and cough (63.4%). During follow-up, the rate of hospitalization and death were 45.2% and 4.3%, respectively. Previous comorbidities (β = 0.61) and mean prednisolone dosage above 10 mg/day in the last 3 months (β = 1.10) significantly increased COVID-19 severity. Also, vaccination against SARS-CoV-2 (β = -1.50) and each passing month from the last rituximab dose decreased severity (β = -0.02). Notably, 19.3% of the patients developed AIBD flare-ups following COVID-19 infection. Higher prednisone dose and the shorter interval from the last rituximab infusion were determinants of severe COVID-19. Physicians should assess the risk versus the benefits when prescribing the medications. Moreover, vaccination could successfully attenuate COVID-19 severity.

Factors associated with the healing time of pemphigus vulgaris oral lesions: a prospective study

OBJECTIVES

This study determines the healing time of lesions on different locations and the contributing factors to the healing time in patients with pemphigus.

METHODS

In this prospective study, newly diagnosed patients with mucosal lesions were included. A dermatologist evaluated the lesions, disease status, side effects and assigned the PDAI. Follow-up visits were conducted monthly until the patient reached complete remission and every three months thereafter. A Tzanck smear was performed on lesions clinically suspected to be herpetic in origin.

RESULTS

Sixty patients enrolled in the study with a mean age of 45.9 ± 11.7 years. The buccal lesions took the longest to resolve(73[33.5-105.5] days). However, the posterior pharynx lesions showed the shortest healing time(20[13.0-25.5] days). The likelihood of improvement in buccal and soft palate lesions decreased by 5% and 3% with each additional year of age, respectively. Also, the resolution duration of soft palate lesions was significantly shorter in female patients than males(median of 24.0 days vs. 38.5 days). In contrast, lower gingival lesions resolve significantly faster in male patients by a median of 9 days. HSV infection increases the healing time of lesions by 26 days(median of 55 days vs. 29 days, hazard ratio 2.62, 95%CI:1.04-5.92).

CONCLUSIONS

Buccal and lower gingival lesions are more recalcitrant to treatment, while posterior pharynx lesions heal most rapidly. Furthermore, older age was also associated with a lower rate of lesion improvement.

Secondary Dysgammaglobulinemia in Children with Hematological Malignancies Treated with Targeted Therapies

Targeted therapies have emerged as innovative treatments for patients whose disease does not respond to conventional chemotherapy, and their use has widely expanded in the field of pediatric hematologic malignancies in the last decade. While they carry the promise of improved disease control and survival and are currently investigated in first-line treatment protocols for patients with poor prognostic markers, they are associated with a considerable incidence of specific toxicities, including cytokine-release syndrome, neurotoxicity, hepatotoxicity, nephrotoxicity, cardiotoxicity, endocrine adverse events, and infectious complications. Iatrogenic or secondary dysgammaglobulinemia is a main consequence of targeted therapies using monoclonal antibodies and other antibody-derived treatments that target specific antigens on lymphoid cells (blinatumomab, inotuzumab ozogamicin, rituximab), chimeric antigen receptor T cells, tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib) and, to a lesser extent, checkpoint inhibitors (pembrolizumab, nivolumab). This review discusses the diagnosis and incidence of secondary or iatrogenic dysgammaglobulinemia in children treated with targeted therapies for leukemias and lymphomas, and options for monitoring and treatment.

Current status and prospects for the diagnosis of pemphigus vulgaris

Introduction: Pemphigus vulgaris (PV) is an intraepidermal autoimmune bullous disease (AIBD) characterized by autoantibodies against desmosomal adhesion proteins, most commonly desmoglein (Dsg)3, leading to the suprabasal cleft formation and acantholysis.Areas covered: Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) studies display the intercellular deposition of IgG/C3 throughout the epidermis and presence of circulating autoantibodies respectively, as a net-like pattern. However, the target antigen remains unknown using immunofluorescence techniques. Thanks to the development of Dsg ELISA, using recombinant technology, circulating antibodies against Dsg1 and 3 could be detected sensitively. It is possible to differentiate PV from pemphigus foliaceus (PF) using this assay. BIOCHIP mosaic and multivariant ELISA are two novel serologic methods with the added value of the ability to screen several AIBDs simultaneously.Non-Dsg1/3 antigens are also involved in the pathogenesis of PV and investigated more deeply thanks to the protein microarrays technique. Additionally, patients with high values of anti-Dsg1/3 may be lesion-free, suggesting the presence of nonpathogenic autoantibodies.Expert opinion: Newer diagnostic methods to replace traditional techniques should possess high sensitivity and specificity and be widely available, noninvasive, and relatively cheap. The newly developed methods need to be further evaluated before being recommended for routine use.

Therapeutic approaches and targets for treatment of autoimmune bullous diseases

Autoimmune bullous diseases are a heterogeneous group of diseases characterized by the development of cutaneous and mucosal vesicles, blisters, and finally erosions. The common pathogenetic mechanism is the presence of autoantibodies targeting structural proteins of the skin and mucous membranes (demosomes and hemidesmosomes): in the case of pemphigus, the antigens are intraepidermal, whereas in the case of pemphigoid, dermatitis herpetiformis, and epidermolysis bullosa acquisita they are subepidermal. Mucosal involvement typically affects the oral and ocular mucosa, but in some cases, the upper airways or the upper digestive tract are affected. The burden on patients' lives could be severe due to the impairment of normal feeding or breathing. In other cases, they may represent paraneoplastic syndromes. Since autoimmune bullous diseases may result in significant morbidity and mortality, depending on the grade of cutaneous and mucosal involvement, a prompt therapeutic approach is mandatory and, in recalcitrant cases, may be challenging. The first line therapy consists of corticosteroids, both topical and systemic. Once remission or control of the acute phase is obtained, adjuvant therapies need to be introduced in order to spare the corticosteroid load and minimize side effects such as iatrogenic diabetes or osteoporosis. Herein, we describe all current therapeutic approaches to autoimmune bullous diseases, also including emerging therapies.

Modifications of the BAFF/BAFF-Receptor Axis in Patients With Pemphigus Treated With Rituximab Versus Standard Corticosteroid Regimen

The efficacy of the B-cell-depleting agent rituximab has been reported in immune diseases but relapses are frequent, suggesting the need for repeated infusions. The B-cell activating factor (BAFF) is an important factor for B cell survival, class switch recombination and selection of autoreactive B cells, as well as maintaining long-lived plasma cells. It has been hypothesized that relapses after rituximab might be due to the increase of serum BAFF levels. From the Ritux3 trial, we showed that baseline serum BAFF levels were higher in pemphigus patients than in healthy donors (308 ± 13 pg/mL versus 252 ± 28 pg/mL, p=0.037) and in patients with early relapse compared who didn't (368 ± 92 vs 297 ± 118 pg/mL, p=0.036). Rituximab and high doses of CS alone have different effects on the BAFF/BAFF-R axis. Rituximab led to an increase of BAFF levels associated to a decreased mRNA (Day 0: 12.3 ± 7.6 AU vs Month 36: 3.3 ± 4.3 AU, p=0.01) and mean fluorescence intensity of BAFF-R in non-autoreactive (Day 0: 3232 vs Month 36: 1527, mean difference: 1705, 95%CI: 624 to 2786; p=0.002) as well as on reappearing autoreactive DSG-specific B cells (Day 0: 3873 vs Month 36: 2688, mean difference: 1185, 95%CI: -380 to 2750; p=0.20). Starting high doses of corticosteroids allowed a transitory decrease of serum BAFF levels that re-increased after doses tapering whereas it did not modify BAFF-R expression in autoreactive and non-autoreactive B cells. Our results suggest that the activation of autoreactive B cells at the onset of pemphigus is likely to be related to the presence of high BAFF serum levels and that the decreased BAFF-R expression after rituximab might be responsible for the delayed generation of memory B cells, resulting in a rather long period of mild pemphigus activity after rituximab therapy. Conversely, the incomplete B cell depletion and persistent BAFF-R expression associated with high BAFF serum levels might explain the high number of relapses in patients treated with CS alone.