Dupilumab as a novel steroid-sparing treatment for IgG4-related disease

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

Pharmacological Management of IgG4-Related Disease: From Traditional to Mechanism-Based Targeted Therapies

IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by organ enlargement and dysfunction. The formation of tertiary lymphoid tissues (TLTs) in affected organs is crucial for understanding IgG4-RD, as T follicular helper (Tfh) 2 cells within TLTs drive IgG4+B cell differentiation, contributing to mass formation. Key cytokines IL-4 and IL-10, produced by Tfh2 cells, are essential for this process. Additionally, cytotoxic T cells and M2 macrophages significantly contribute to inflammation and fibrosis in the lesions. These insights into IgG4-RD have led to the development of innovative targeted therapies. While glucocorticoids are effective in many cases, they often cause disease flares during tapering and rarely result in long-term, treatment-free remissions. Long-term glucocorticoid use poses significant challenges owing to potential side effects, particularly in older patients who may already have complications such as diabetes and atherosclerotic diseases. In contrast, targeted therapies offer a promising alternative, potentially providing more effective disease control with fewer side effects. Current research is exploring several exciting approaches, including B-cell depletion, targeted immunomodulation of B cells, Bruton's tyrosine kinase inhibition, disruption of co-stimulation pathways, targeting the SLAMF7 cytokine or its receptor blockade (BAFF, IL-4, or IL-6), and JAK-STAT signaling pathway inhibition. These emerging strategies hold the promise of improving patient outcomes and advancing the management of IgG4-RD.

A case of immunoglobulin G4-related disease complicated by atopic dermatitis responsive to upadacitinib treatment

Immunoglobulin G4-related disease (IgG4-RD) is mainly treated with glucocorticoids. In many cases, this disease is resistant to glucocorticoids, and their toxicity can be a problem. We encountered a patient with IgG4-RD affecting multiple organs (such as the skin, lung, and lacrimal gland), who had comorbidities, including atopic dermatitis and diabetes. In this case, while glucocorticoid tapering was difficult, the introduction of upadacitinib resulted in the remission of both atopic dermatitis and IgG4-RD without glucocorticoid dose escalation. Peripheral blood flow cytometry analysis showed that the proportions of activated non-Th1/Th17 cell subset (Th2 cells), follicular helper T cells, and plasmocytes were increased before upadacitinib therapy, but all normalised after treatment. Interleukin-4 and interleukin-21 signals are important for the differentiation of CD4+ T cells into type 2 helper T or B cells in the peripheral blood. Our case suggested that inhibition of Janus kinase 1, which mediates these signals, might have contributed to improved pathological conditions in IgG4-RD.

IgG4-related Disease: Recent Topics on Immunological Aspects of This Disorder and Their Application in New Treatment Strategies

IgG4-related disease (IgG4-RD) is a systemic and chronic inflammatory disorder that can affect every part of the body. The formation of tertiary lymphoid tissues (TLT) in the affected organs may be a key phenomenon in understanding the pathogenesis of this disease because T follicular helper (Tfh) 2 cells play an important role in IgG4 class switching within TLT in the affected organs or tissues. TLT formation leads to the formation of masses or swelling of the affected organs. Interleukin (IL)-4 and IL-10 are critical cytokines for IgG4-class switching and are produced in TLT. Other factors, such as CD4-positive (CD4+) cytotoxic T cells, M2 macrophages, and LAG3+ Tfh cells, have been identified as disease-specific contributors to lesion formation. In this review, I describe the current knowledge necessary to understand the pathogenesis of this disease and recent developments in treatment strategies beyond B-cell depletion therapy.

Overview of Immunological Response in Urological Membranous Nephropathy: Focus on Cytokine and Treatment Options

Membranous nephropathy (MN) is an autoimmune disease that is caused by the production of autoantibody against glomerular podocyte antigens by immune cells due to the lack of self-tolerance mechanisms. Similar to many autoimmune diseases, the pathogenesis of MN is still vague and many experiments are being conducted to detect the antigens and genetic reasons for MN illness. Recently, new antigens, such as exotosin 1/exotosin 2, neural EGF-like-1, semaphorin 3B, and protocadherin 7 have been identified in MN patients who did not have presence of antiphospholipase A2 receptor antigen. What is more, cytokines, which are molecules that regulate immune responses, have been found to have harmful effects in various autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and MN. The role of cytokines and treatment strategies in MN patients is discussed in this article. As the understanding of the disease improves, targeted therapies that focus on specific antigens or cytokines may be developed to effectively manage MN.

Microbe-associated molecular patterns derived from fungi and bacteria promote IgG4 antibody production in patients with type 1 autoimmune pancreatitis

Enhanced IgG4 antibody (Ab) response is a prominent feature of type 1 autoimmune pancreatitis (AIP). Innate immune responses associated with IgG4 Ab production are poorly defined. We have previously reported that peripheral blood mononuclear cells (PBMCs) isolated from patients with type 1 AIP produce large amounts of IgG4 Abs upon stimulation with bacterial cell wall components. In addition, we showed that activation of plasmacytoid dendritic cells producing interferon (IFN)-α, interleukin (IL)-33, and B cell-activating factor (BAFF) upon sensing intestinal bacteria mediates the development of experimental AIP. In this study, we attempted to clarify the role of innate immunity against fungi in inducing enhanced IgG4 Ab responses in type 1 AIP. PBMCs isolated from healthy controls and patients with type 1 AIP were stimulated with a broad range of bacterial and fungal cell wall components. The concentrations of IgG1, IgG4, and cytokines were measured using enzyme-linked immunosorbent assays. Cell wall components derived from bacteria and fungi induced IgG1 and IgG4 Ab production in patients with type 1 AIP. Various types of microbe-associated molecular pattern motifs enhanced IgG4 Ab production in patients with type 1 AIP compared with the limited motifs in healthy controls. The enhanced IgG1 and IgG4 Ab production that followed in response to bacterial and fungal cell wall components was parallel to that of IFN-α, IFN-γ, IL-10, IL-33, and BAFF. In conclusion, cell wall components derived from fungi as well as bacteria promote IgG4 Ab responses in patients with type 1 AIP.

A case of IgG4-related disease associated with ulcerative colitis that was successfully treated with a JAK inhibitor

Glucocorticoids (GC) are the standard of care for the induction and maintenance of remission in immunoglobulin G4 (IgG4)-related diseases. However, IgG4-related diseases often relapse with GC dose reduction, not only making GC dose reduction difficult but also necessitating GC dose escalation in many cases. Therefore, other immunosuppressive drugs are required to maintain remission. Here, we report a 39-year-old man with ulcerative colitis and IgG4-related disease who experienced a relapse of both diseases despite treatment with tacrolimus and 6-mercaptopurine. Following the initiation of tofacitinib, a Janus-associated kinase inhibitor, it was possible to reduce the GC dose while maintaining remission of both diseases. This case highlights the potential utility of Janus-associated kinase inhibitors in managing complex cases of IgG4-related disease, especially those with concurrent conditions such as ulcerative colitis.

Pathogenic roles of follicular helper T cells in IgG4-related disease and implications for potential therapy

IgG4-related disease (IgG4-RD) is a recently described autoimmune disorder characterized by elevated serum IgG4 levels and tissue infiltration of IgG4+ plasma cells in multiple organ systems. Recent advancements have significantly enhanced our understanding of the pathological mechanism underlying this immune-mediated disease. T cell immunity plays a crucial role in the pathogenesis of IgG4-RD, and follicular helper T cells (Tfh) are particularly important in germinal center (GC) formation, plasmablast differentiation, and IgG4 class-switching. Apart from serum IgG4 concentrations, the expansion of circulating Tfh2 cells and plasmablasts may also serve as novel biomarkers for disease diagnosis and activity monitoring in IgG4-RD. Further exploration into the pathogenic roles of Tfh in IgG4-RD could potentially lead to identifying new therapeutic targets that offer more effective alternatives for treating this condition. In this review, we will focus on the current knowledge regarding the pathogenic roles Tfh cells play in IgG4-RD and outline potential therapeutic targets for future clinical intervention.

Current and future advances in practice: IgG4-related disease

IgG4-related disease (IgG4-RD) is an increasingly recognized cause of fibroinflammatory lesions in patients of diverse racial and ethnic backgrounds and is associated with an increased risk of death. The aetiology of IgG4-RD is incompletely understood, but evidence to date suggests that B and T cells are important players in pathogenesis, both of which are key targets of ongoing drug development programmes. The diagnosis of IgG4-RD requires clinicopathological correlation because there is no highly specific or sensitive test. Glucocorticoids are highly effective, but their use is limited by toxicity, highlighting the need for studies investigating the efficacy of glucocorticoid-sparing agents. B cell-targeted therapies, particularly rituximab, have demonstrated benefit, but no randomized clinical trials have evaluated their efficacy. If untreated or under-treated, IgG4-RD can cause irreversible organ damage, hence close monitoring and consideration for long-term immunosuppression is warranted in certain cases.

Immune dysregulation in immunoglobulin G4-related disease

(IgG4-RD) is an immune-mediated fibrotic disorder characterized by severe resolution of inflammation and dysregulation of wound healing. IgG4-RD has been considered a unique disease since 2003, and significant progress has been achieved in the understanding of its essential features. The central role of B cells in IgG4-RD has been demonstrated by the robust clinical responsiveness of IgG4-RD to B cell depletion and the identification of multiple self-antigens that promote B cell expansion. Studies have increasingly revealed critical roles of these B cells and T cells in the pathogenesis of IgG4-RD, and we and other authors further identified CD4⁺ cytotoxic T lymphocytes as the main tissue-infiltrating CD4⁺ T cell subset in IgG4-RD tissues. Additionally, T follicular helper cell subsets that play a role in IgG4 isotype switching have been identified. In this review, we discuss research on IgG4-RD and the roles of B cell and T cell subsets, as well as the functions of CD4⁺ cytotoxic T cells in IgG4-RD pathogenesis. We highlight our findings from ongoing research using single-cell analysis of infiltrating CD4⁺ cytotoxic T cells, CD4⁺ follicular helper T cells, and infiltrating B cells in IgG4-RD and propose a model for the pathogenesis of IgG4-RD.

Therapeutic Uses of Rituximab and Clinical Features in Immunoglobulin G4-Related Disease: A Systematic Review

This research presents a systematic review focusing on rituximab's therapeutic applications in immunoglobulin G4 (IgG4)-related disease (IgG4-RD), a rare condition characterized by immune-mediated systemic inflammation and tissue fibrosis, as well as the clinical features of IgG4-RD. While the disease commonly affects organs such as the bile ducts, lymph nodes, retroperitoneum, pancreas, and salivary glands, it can potentially involve other organs. This intricacy often leads to diagnostic challenges due to clinical overlaps with cancer, infections, and other autoimmune disorders. The diagnosis of IgG4-RD necessitates a comprehensive approach involving laboratory tests, imaging studies, and clinical assessments. Symptoms can vary, ranging from lymphadenopathy to jaundice, affecting multiple organs. Although elevated blood IgG4 levels and findings of tissue involvement and fibrosis on imaging can be suggestive, they lack the specificity for a definitive diagnosis. Early diagnosis is crucial for initiating corticosteroids and immunosuppressive to prevent further damage from IgG4-RD. This study highlights the therapeutic role of rituximab in managing this condition. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria, the research identifies and evaluates relevant literature across various electronic databases, including PubMed, ScienceDirect, and Google Scholar. This review includes 14 selected publications, comprising three systematic reviews, three observational studies, four narrative reviews, and four case reports. The study design ensures a comprehensive evaluation of rituximab's potential efficacy in treating IgG4-RD and its associated clinical characteristics. Based on this study, it can be concluded that IgG4-RD can potentially be treated with rituximab, particularly in cases of relapse and maintaining remission.

Pembrolizumab-associated expansion of radiation-induced morphoea responsive to dupilumab: a case report

Immune checkpoint inhibition (ICI) can induce progression of pre-existing radiation-induced morphoea beyond the irradiated field and into deeper structures including the muscle and fascia. Dupilumab, an interleukin-4 receptor antagonist, should be considered in patients with refractory radiation or ICI-induced morphoea and may allow for continued anticancer treatment.

Long-term efficacy of anti-IL-4 receptor antibody in a patient with aspirin-exacerbated respiratory disease and IgG4-related disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) and IgG4-related disease (IgG4RD) share a common pathway of Th2-mediated immune mechanism; there have been several cases of IgG4RD developed in patients with asthma, especially in those comorbid with chronic rhinosinusitis (CRS). IgG4RD has often been treated with systemic corticosteroids, rituximab, or immune-suppressive agents, but frequently failed with relapse.

CASE PRESENTATION

Here, we present a case of a 64-year-old male patient with severe AERD with CRS complicated with IgG4RD, who has been successfully treated and maintained with anti-IL-4 receptor antibody, dupilumab after achieving unsatisfactory responses with previous treatments including steroids, rituximab, omalizumab, and reslizumab. The patient's symptoms (periorbital swelling and asthmatic/nasal symptoms) were remarkably improved; serum levels of IgG4/IgE as well as plasmablast/eosinophil counts progressively decreased without any recurrence sign for over 2 years of dupilumab treatment.

CONCLUSION

These findings demonstrate that blocking the IL-4/IL-13 pathway with dupilumab can be an effective treatment with long-term safety in patients with severe AERD with CRS complicated by IgG4RD.

Implication of allergy and atopy in IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a chronic multi-organic immune fibrosing disease. It affects preferentially men around middle age and almost any organs can be involved; however, lymph nodes, submandibular and lacrimal glands, pancreas, and retroperitoneum are the most affected. The mainstay treatment is corticosteroids, sometimes adjuncts with DMARDs or rituximab as steroid sparing agents. Th2 inflammation is implicated in the pathophysiology of the disease. Several reports indicate that allergy and/or atopy often affect patients with IgG4-RD. The frequency varies greatly between studies with allergies/allergic diseases reported in 18-76% while atopy is reported in 14-46%. In studies including both, they affect 42 and 62% of patients. Rhinitis and asthma are the most frequent allergic diseases. IgE and blood eosinophiles are often elevated and few studies report that basophils and mast cells could participate in the disease pathogenesis; however, the implication of allergy and atopy remain unclear. No common allergen has been identified and IgG4 production seems to be polyclonal. Although a direct causal effect is unlikely, they could potentially shape the clinical phenotype. Allergies/allergic diseases and/or atopy are reported to be more frequent in IgG4-RD patients presenting head, neck, and thoracic involvement, with higher IgE and eosinophils and less frequent in retroperitoneal fibrosis; however, studies regarding allergy and atopy in IgG4-RD are highly heterogenous. The aim of this article is to review what is currently known about the allergy and atopy in the context of Ig4-RD.

Dupilumab in Inflammatory Skin Diseases: A Systematic Review

Dupilumab was first approved for the treatment of atopic dermatitis (AD) and blocks the signaling of interleukin (IL)-4 and -13. Several other chronic skin conditions share mechanistic overlaps with AD in their pathophysiology, i.e., are linked to type 2 inflammation. Most recently, dupilumab was approved by the U.S. Food and Drug Administration for prurigo nodularis (PN). Given its relatively good safety profile, effective off-label use of dupilumab has been reported for a multitude of dermatologic diseases and several clinical trials for dermatologic skin conditions are currently ongoing. We conducted a systematic review of applications of dupilumab in dermatology other than AD and PN by searching the databases PubMed/Medline, Scopus, Web of Science and Cochrane Library as well as the clinical trial registry ClinicalTrials.gov. We found several reports for effective treatment of bullous autoimmune diseases, eczema, prurigo, alopecia areata, chronic spontaneous urticaria, Netherton syndrome and a variety of other chronic inflammatory skin diseases.

Development of targeted therapies in IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic disease characterized by high serum IgG4 levels, infiltration of lymphocytes and IgG4-positive plasma cells into affected tissues, and subsequent fibrosis, forming mass, nodular, and thickened lesions in organs. Although glucocorticoids (GCs) are the first-line treatment for IgG4-RD, the disease often relapses during dose reduction or after discontinuation of GC. Long-term treatment with GC is associated with adverse effects such as infection, osteoporosis, and atherosclerosis. Therefore, there is an urgent need to develop a treatment strategy that specifically addresses the pathogenesis of IgG4-RD. As immunocompetent cells and immune-related molecules involved in the pathogenesis of IgG4-RD are increasingly being identified, there is a growing demand for new molecular-targeted drugs that target them. In particular, favourable results have been reported for drugs that target B cells, such as anti-cluster of differentiation (CD)20 and anti-CD19 antibodies. In addition, clinical trials are underway for new therapeutic agents, such as anti-signalling lymphocytic activation molecule family 7 antibodies that target T cells and other cells.

IgG4-related disease administered dupilumab: case series and review of the literature

Dupilumab (DUP) is a monoclonal antibody that acts on the interleukin (IL)-4 receptor alpha, which inhibits IL-4 and IL-13 signalling and is approved for type 2 inflammatory diseases such as asthma, chronic rhinosinusitis with nasal polyposis and atopic dermatitis; however, the efficacy of DUP to IgG4-related disease (IgG4-RD) is under discussion due to the controversial outcomes based on the several case reports. Here, we reviewed the efficacy of DUP in four consecutive patients with IgG4-RD in our institute and the previous literature.All patients administered DUP fulfilled the 2019 ACR/EULAR classification criteria for IgG4-RD complicated with severe asthma and chronic rhinosinusitis with nasal polyposis. Two cases were administered DUP without systemic glucocorticoids (GCs), and in 6 months, the volume of swollen submandibular glands (SMGs) was reduced by approximately 70%. Two cases receiving GCs successfully reduced their daily dose of GCs (10 and 50% reduction, respectively) with dupilumab in 6 months. In all four cases, serum IgG4 concentration and IgG4-RD responder index decreased in 6 months.DUP reduced the volume of the swollen SMGs, serum IgG4 levels, responder index and the daily dose of GCs in patients with IgG4-RD with severe asthma or eosinophilic rhinosinusitis in 6 months.The efficacy of DUP to IgG4-RD is under discussion due to the limited case reports with controversial outcomes. Here, we demonstrated that two patients with IgG4-RD treated by DUP without systemic GCs, showed volume reduction of swollen SMGs and two cases showed GC-sparing effects by DUP. DUP can ameliorate the disease activity and be a steroid-sparing agent in patients with IgG4-RD.

IgG4 related disease and aortitis: an up-to-date review

Aortic involvement in immunoglobulin G4-related disease (IgG4-RD) is extremely rare and is often overlooked during the aortitis work-up. IgG4-related aortitis differs from non-IgG4-related aortitis in its histopathological features, site of involvement, laboratory markers, and treatment options. The histopathological examination of the vessel walls characteristically reveals adventitial thickening with intimal sparing, typically affecting the infrarenal abdominal aorta. In addition, inadequate knowledge about the disease often leads to delayed or missed diagnosis and undermanagement of a potentially treatable condition. Hence, in this paper, we review the unique clinical manifestations, laboratory markers, diagnostic features, current treatment strategies, and novel experimental therapeutic options in the management of IgG4-related aortitis.

Reduced COVID-19 vaccine response in patient treated with dupilumab for IgG4-related disease

Dupilumab is a novel anti-IL-4 receptor-α mAb that targets the signaling pathways of IL-4 and IL-13. Thus far, the data about adequate humoral immune response after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients who are taking dupilumab have been limited.

Thoracic manifestations of IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a recently described rare systemic fibroinflammatory disease with an estimated incidence of less than 1 in 100,000 persons per year. The disease can affect virtually any organ and is characterized by unifying histopathological findings. Recently, four subgroups of patients have been characterized: hepatobiliary, head and neck, Mikulicz syndrome and retroperitoneal fibrosis, who illustrate the mainly abdominal and ENT tropism of the disease. Yet, thoracic involvement is not uncommon. It can be detected in up to 30% of patients with systemic IgG4-RD and is the exclusive manifestation of the disease in about 10% of cases. Clinical symptoms are nonspecific and may include dyspnoea, cough or chest pain. Chest CT findings are heterogeneous and primarily include peribronchovascular thickening, nodules, ground-glass opacities and lymphadenopathy. There is no specific diagnostic test for IgG4-RD thoracic involvement, which may mimic malignancy or vasculitis. Therefore, a cautious approach is needed to make an accurate diagnosis: a search for extra-thoracic manifestations, elevated serum IgG4 levels, circulating levels of plasmablasts and pathologic evidence of disease is warranted. Although very suggestive, neither the presence of a polyclonal IgG4 lymphoplasmacytic infiltrate, storiform fibrosis or obliterative phlebitis are sufficient to confirm the histological diagnosis. Steroids are recommended as first-line therapy. Rituximab or disease-modifying antirheumatic drugs may be used in relapsed or rare cases of steroid-refractory disease. In this review, we summarize current knowledge regarding the pathophysiology, epidemiology, diagnostic modalities (clinical-biological-imaging-histopathology) and treatment of IgG4-RD thoracic involvement.

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.

Therapy of immunoglonuline IgG4 related disease (IgG4-RD)

Immunoglobulin IgG4 related disease (IgG4-RD) is a heterogeneous disorder with multi-organ involvement recognised as a separate entity at the beginning of this century only. Evolving therapy is reviewed in this paper. Glucocorticoids are first choice drug but long administration of glucocorticoids is connected with many adverse effects. In case of combination glucocorticoids and immunosuppressive agents lower doses of glucocorticoids are needed, the response rate is higher and therapy is better tolerated. Rituximab is drug, that is possible use as monotherapy or in combination with glucocorticoids and immunosuppressive drugs. Only one study compared two immunosuporessive drugs, mycophenolate mofetil and cyclophosphamide. The response rated was similar but remissions were longer after glucocorticoids with cyclophosphamide then glucocorticoids with mycofenolat mofetil. No other comparative study of combination of various imunossupressive drugs with glucocorticoids was published. Rituximab has high number (90 %) of response rate in monotherapy, but can be used in combination with glucocorticoids and immunosuppressives. Rituximab is now preferred and recommended for maintenance therapy administered in 6-month interval. In case of advanced disease, we prefer therefore combination of rituximab, cyclofosphamide and dexamethasone for initial therapy followed by maintenance with rituximab in 6 months interval. There are two new drugs under investigation abatacept and dupilimab with promising results. Although we have very intensive therapies for good results of therapy early diagnosis before irreversible fibrotic changes in IgG4-RD involved organs is still needed.

Dupilumab as an adjunct treatment for a patient with steroid-dependent immunoglobulin G4-related disease complicated by asthma: a case report

Introduction: Immunoglobulin G4-related disease (IgG4-RD) responds well to glucocorticoids but is often associated with relapses. Interleukin (IL)-4 and IL-13 are involved in the pathogenesis of IgG4-RD. We present the first case in which dupilumab was an effective adjunct treatment for a patient with steroid-dependent IgG4-RD complicated by asthma.Case study: A 57-year-old man was referred to our hospital for further investigation and treatment of proptosis with neck swelling in 2019. He developed a cough and swelling of the neck in 2016. He was diagnosed with asthma in 2017 and started receiving inhaled glucocorticoids and a long-acting beta-agonist. The patient started receiving oral prednisolone at a dose of 20 mg/day. Oral prednisolone reduced his symptoms, but he relapsed when treatment was tapered to less than 10 mg/day. He was diagnosed with IgG4-RD through a parotid gland biopsy.Results: Azathioprine was given to reduce systemic glucocorticoids. The prednisolone dose was gradually tapered to 10 mg/day, resulting in the relapse of proptosis and an asthma attack. We added dupilumab, and his asthma symptoms and proptosis improved. Serum IgG4 levels continued to decrease, and the prednisolone dose was tapered to 2 mg.Conclusion: Dupilumab might be useful as an adjunctive treatment for patients with steroid-dependent IgG4-RD complicated by asthma. Serum IgG4 levels can be used as a marker to monitor dupilumab treatment in IgG4-RD.

Significance of high serum IgG4 in complete or non-full-fledged IgG4-related disease-a retrospective investigation of 845 patients and its clinical relevance

OBJECTIVE

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized heterogeneous, subacute, and usually silent autoimmune disease involving many organs with protean manifestations. However, high IgG4 in serum is not necessarily indicating an IgG4-RD. The aims of this study were to investigate the clinical relevance of high serum IgG4 level in IgG4-RD or non IgG4-RD patients, and to see if IgG4-RD in Taiwan differs from that in other parts of the world.

METHODS

Eight hundred forty-five patients with high IgG4 were retrospectively reviewed from January 2002 to May 2020 in Taipei Veteran General Hospital. Two hundred sixty-seven patients fulfilled IgG4-RD criteria and were categorized into pancreato-hepato-biliary disease, retroperitoneal fibrosis and/or aortitis, head/neck-limited disease, classic Mikulicz syndrome with systemic involvement, CNS-limited disease, sclerosing vasculitis, skin-limited disease, and sensorineural hearing disease. These manifestations were correlated to smoking, atopy, hyper-IgE/eosinophilia, aging, malignancies, and hypocomplementemia. Five hundred seventy-eight patients were not fulfilling the criteria but were also analyzed for the prevalence of allergy, malignancy, connective tissue diseases, lung diseases, and infections.

RESULTS

In IgG4-RD patients, 124 (46.4%) smoked. Top 4 clinical subtypes included Mikulicz syndrome with systemic involvement (33.3%), pancreato-hepatobiliary disease (31.4%), head/neck disease (19.4%), and retroperitoneal fibrosis/aortitis (12.7%). Top 4 co-morbid conditions included high serum IgE/eosinophilia (46.2%), hypocomplementemia (34%), malignancies (13.4%), and allergy (13.4%). Pancreato-biliary disease was associated with high IgE/eosinophilia (r² = 0.380, P = 0.025) and malignancy (r² = 0.211, P = 0.027), Miculicz syndrome with allergy (r² = 0.396, P < 0.01) and high IgE/eosinophil (r² = 0.396, P < 0.01), CNS diseases (r² = 0.973, P = 0.035) and sclerosing vasculitis (r² = 1, P < 0.01) with advanced age respectively, with the latter being also related to atopy and high IgE/eosinophilia (r² = 1, p < 0.01).

CONCLUSION

Smoking may precipitate IgG4-RD. IgG4-RD with pancreato-hepatobiliary disease is closely related to allergy and neoplasm, and those with Mikulicz syndrome may result from atopy. Elderly IgG4-RD patients tend to develop CNS pathology parallel to advancing of age. The disease may probably be originated from an unknown mechanism that may sporadically evolve into malignancies.

IgG4-related disease and idiopathic multicentric Castleman's disease: confusable immune-mediated disorders

IgG4-related disease (IgG4-RD) and idiopathic multicentric Castleman's disease (iMCD) are both rare systemic immune-mediated disorders. However, pathogenesis differs markedly between the two diseases, and differing therapeutic strategies are adopted: IgG4-RD is treated using a moderate dose of glucocorticoids or rituximab, while iMCD therapy involves an interleukin (IL)-6 targeted approach. Nonetheless, some clinical features of IgG4-RD and iMCD overlap, so differential diagnosis is sometimes difficult, even though the classification and diagnostic criteria of the diseases require careful exclusion of the other. The key findings in IgG4-RD are high IgG4/IgG ratio, allergic features, and germinal centre expansion involving T follicular helper cells, while iMCD involves polyclonal antibody production (high IgA and IgM levels), sheet-like mature plasma cell proliferation, and inflammatory features driven by IL-6. The distribution of organ involvement also provides important clues in both diseases. Particular attention should be given to differential diagnosis using combined clinical and/or pathological findings, because single features cannot distinguish IgG4-RD from iMCD. In the present review, we discuss the similarities and differences between IgG4-RD and iMCD, as well as how to distinguish the two diseases.

Treatment options for DOCK8 deficiency-related severe dermatitis

BACKGROUND

Cutaneous manifestations of dedicator of cytokinesis 8 gene (DOCK8) deficiency, a combined type of T and B cell immunodeficiency, previously designated as autosomal recessive hyper IgE syndrome, includes dermatitis and skin infections. There are limited treatment options for dermatitis related to the syndrome.

OBJECTIVE

To describe a cohort of patients with DOCK8 deficiency with a focus on the treatment of their cutaneous manifestations.

METHODS

A retrospective study on all children with the genetic diagnosis of DOCK8 deficiency treated at the Sheba Medical Center between 1/1/2003 and 1/1/2021 was preformed. Collected data included: demographic features, family history, laboratory, genetic testing, skin manifestations, treatment, and disease course. Description of two cases of severe recalcitrant dermatitis treated with dupilumab is detailed.

RESULTS

Nine children with a genetic diagnosis of DOCK8 deficiency were included, of whom six were girls (66%) with a median age of 8.5 (±2.2 SD) years. The median age at diagnosis was 2.8 (±2.6 SD) years. Six patients were born to consanguineous parents. Five out of six patients who received hematopoietic stem cell transplantation (HSCT) had a complete response, and one was recently transplanted. Of note, two patients, while awaiting HSCT, were treated with dupilumab for their severe dermatitis resulting in a marked improvement of the cutaneous manifestations and pruritus.

CONCLUSIONS

Hematopoietic stem cell transplantation is the gold standard and most effective therapy for patients with DOCK8 deficiency. Dupilumab, a biological therapy indicated for atopic dermatitis and other Th2 derived dermatoses, is an excellent option for dermatitis in patients with DOCK8 deficiency and can be used as a bridge before HSCT. Larger studies are needed to confirm this observation.

Biomarkers in autoimmune pancreatitis and immunoglobulin G4-related disease

Solitary organ autoimmune disorders, formerly known as autoimmune pancreatitis (AIP), autoimmune sialadenitis, and autoimmune sclerosing cholangitis, are now considered organ-specific manifestations of systemic immunoglobulin G4-related disease (IgG4-RD). AIP and IgG4-RD are characterized by elevated serum concentration of IgG4 antibody (Ab), accumulation of IgG4-expressing plasmacytes in the affected organs, and involvement of multiple organs. It is well established that enhanced IgG4 Ab responses are a hallmark of AIP and IgG4-RD for diagnosis and monitoring disease activity. However, a significant fraction of patients with AIP and IgG4-RD who develop chronic fibroinflammatory responses have normal serum concentrations of this IgG subtype. In addition, disease flare-up is sometimes seen even in the presence of normalized serum concentrations of IgG4 Ab after successful induction of remission by prednisolone. Therefore, it is necessary to identify new biomarkers based on the understanding of the pathophysiology of AIP and IgG4-RD. Recently, we found that activation of plasmacytoid dendritic cells producing both interferon-α (IFN-α) and interleukin-33 (IL-33) mediate murine AIP and human IgG4-RD. More importantly, we provided evidence that serum concentrations of IFN-α and IL-33 could be useful biomarkers for the diagnosis and monitoring of AIP and IgG4-RD activity after induction of remission in these autoimmune disorders. In this Frontier article, we have summarized and discussed biomarkers of AIP and IgG4-RD, including Igs, autoAbs, and cytokines to provide useful information not only for clinicians but also for researchers.

Emerging therapy options for IgG4-related disease

INTRODUCTION

Awareness of IgG4-related disease (IgG4-RD) is increasing worldwide and specialists are now familiar with most of its clinical manifestations and mimickers. IgG4-RD promptly responds to glucocorticoids and repeated courses are typically used to induce and maintain remission because the disease relapses in most patients. If left untreated, it can lead to organ dysfunction, organ failure and death. Advancement in our understanding of IgG4-RD pathogenesis is leading to the identification of novel therapeutic targets and emerging treatments are now setting the stage for personalized therapies for the future.

AREAS COVERED

This review focuses on emerging treatment options for IgG4-RD based on our advancing understanding of disease pathophysiology. Research was performed in the English literature on Pubmed and clinicaltrials.gov databases.

EXPERT OPINION

Glucocorticoids remain the first-line induction treatment for the multi-organ manifestations of IgG4-RD. Alternative immunosuppressive agents for maintaining remission are warranted in order to avoid long-term steroid toxicity, and to offer a more mechanistic and personalized therapeutic strategy. Targeting B and T-lymphocyte activation represents the most promising approach, but randomized controlled trials are eagerly awaited to confirm positive preliminary experiences reported in case series and small cohort studies.

The enigmatic immunoglobulin G4-related disease and its varied cardiovascular manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterised by multiorgan lymphoplasmacytic infiltration, obliterative phlebitis and storiform fibrosis. It can be associated with cardiovascular pathology. The objective of this narrative review is to summarise the published literature on cardiovascular manifestations of IgG4-RD and to provide a basis for diagnosis and management of the condition by the practising cardiologist.We propose the following categorisations of cardiovascular IgG4-RD: aortitis, medium-vessel arteritis, pulmonary vascular disease, phlebitis, valvulopathy, pericarditis, myocardial disease and antineutrophilic cytoplasmic antibody-associated vasculitis. We also review herein developments in radiological diagnosis and reported medical and surgical therapies. Cardiovascular lesions frequently require procedural and/or surgical interventions, such as aortic aneurysm repair and valve replacement. IgG4-RD of the cardiovascular system results in serious complications that can be missed if not evaluated aggressively. These are likely underdiagnosed, as clinical presentations frequently mimic cardiovascular disease due to more common aetiologies (myocardial infarction, abdominal aortic aneurysm and so on). While systemic corticosteroids are the mainstay of IgG4-RD treatment, biological and disease-modifying agents are becoming more widely used. Cardiologists should be aware of cardiovascular IgG4-RD as a differential diagnosis, and understand the roles of corticosteroids, disease-modifying agents and biologicals, as well as their integration with surgical approaches. There are several knowledge gaps, including diagnosis, risk factors, pathogenesis and appropriate management in Ig4-RD of the cardiovascular system. Areas lacking well-conducted randomized trials include safety of steroids in the setting of vascular aneurysms and the role of disease-modifying drugs and biological agents in patients with established cardiovascular complications of this multifaceted enigmatic disease.

Multi-organ IgG4-related disease continues to mislead clinicians: A case report and literature review

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a multisystemic mass forming immune-mediated disease that affects almost every organ and is a diagnostic challenge for every clinician. There is a lack of adequate epidemiological data worldwide, and evidence-based treatment recommendations are not yet established. We report the first case of IgG4-RD from Lithuania and the Baltic Sea region presented with thyroiditis, orbital myositis, orbitopathy, uveitis, scleritis, sialadenitis, autoimmune pancreatitis and prostatitis.

CASE SUMMARY

A 54-year-old Caucasian male was admitted to our tertiary Centre complaining of severe weight loss, diarrhoea, abdominal pain, salivary gland swelling, sicca symptoms and diplopia. On examination, bilateral palpable masses in the projection of major salivary glands, severe protrusion of the left eyeball and cachexia were noted. The patient was previously diagnosed with autoimmune thyroiditis and endocrine ophthalmopathy. The magnetic resonance imaging (MRI) of the head revealed enlarged extraocular muscles indicating orbital myositis. The biopsy from the salivary gland mass indicated sialadenitis. Abdominal MRI showed signs of autoimmune pancreatitis, and a serological test revealed the elevated serum IgG4 concentration. The patient was then diagnosed with IgG4-RD and successfully treated with prednisolone. There was a significant clinical, serological and radiological improvement after one month of treatment and no signs of relapse within twenty months. However, it took almost 18 years and the efforts of eight different medical specialists to establish the correct diagnosis.

CONCLUSION

A comprehensive approach to the patient is essential to improving the recognition of rare immune system conditions, such as IgG4-RD.

Advances in the diagnosis and management of IgG4 related disease

IgG4 related disease was recognized as a unified disease entity only 15 years ago. Awareness of IgG4 related disease has increased worldwide since then, and specialists are now familiar with most of its clinical manifestations. Involvement of the pancreato-biliary tract, retroperitoneum/aorta, head and neck, and salivary glands are the most frequently observed disease phenotypes, differing in epidemiological features, serological findings, and prognostic outcomes. In view of this multifaceted presentation, IgG4 related disease represents a great mimicker of many neoplastic, inflammatory, and infectious conditions. Histopathology remains key to diagnosis because reliable biomarkers are lacking. Recently released classification criteria will be invaluable in improving early recognition of the disease. IgG4 related disease is highly treatable and responds promptly to glucocorticoids, but it can lead to end stage organ failure and even death if unrecognized. Prolonged courses of corticosteroids are often needed to maintain remission because the disease relapses in most patients. Rapid advancement in our understanding of the pathophysiology of IgG4 related disease is leading to the identification of novel therapeutic targets and possible personalized approaches to treatment.