Emerging therapy options 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.

B cell depletion after treatment with rituximab predicts relapse of IgG4-related disease

OBJECTIVES

B cell depletion therapy with rituximab is effective in most patients with IgG4-related disease (IgG4-RD) but requires repeated cycles to prevent disease flares. We here aimed to assess B cells after rituximab to predict relapse of IgG4-RD and guide retreatment.

METHODS

Patients with active IgG4-RD included in this retrospective study fulfilled the ACR/EULAR Classification Criteria. Total CD19+ B cells, plasmablasts, naïve and memory B cells were measured on peripheral blood by flow-cytometry at baseline and 6 months after rituximab. All patients were treated with two 1 g infusions of rituximab 15 days apart and monitored for 48 months. Disease response was assessed using the IgG4-RD Responder Index.

RESULTS

Thirty-three patients were included. Six months after rituximab, disease response was observed in all patients. Complete depletion of CD19+ B cells, plasmablasts, naïve and memory B cell depletion was achieved in 30%, 55%, 39% and 42% of cases, respectively. Twenty-three relapses (70%) were observed at a median time of 24 months after rituximab. Relapse rate was significantly higher in patients who failed to achieve complete depletion of CD19+ cells (60% vs 17%, P = 0.02), naïve B cells (54% vs 15%, P = 0.01), or memory B cells (50% vs 16%, P = 0.03) 6 months after rituximab. The median relapse free survival time was shorter in patients who failed to achieve complete depletion of CD19+ cells (19 vs 38 months, P = 0.02), naïve B cells (16 vs 38 months, P = 0.01), or memory B cells (19 vs 38 months, P = 0.03) 6 months after rituximab.

CONCLUSION

The degree of B cell depletion 6 months after rituximab may predict disease flare and may instruct on the pacing of B cell depletion therapy in IgG4-RD.

Multicentre, 26-week, open-label phase 2 trial of the JAK inhibitor filgotinib in Behçet's disease, idiopathic inflammatory myopathies and IgG4-related disease: DRIMID study protocol

INTRODUCTION

Research into novel therapies for rare, immune-mediated inflammatory diseases (IMIDs) faces significant challenges, including small patient populations, complex clinical trial design and difficulties in patient recruitment. Patients with Behçet's disease (BD), idiopathic inflammatory myopathies (IIM) and IgG4-related disease (IgG4-RD) typically undergo treatment involving prolonged administration of high-dose glucocorticoids and immunosuppressants. Both are associated with an increased risk of infection. Additionally, glucocorticoids carry long-term toxicity risks. Thus, there is an urgent need to develop more targeted and effective anti-inflammatory treatments. Given the activation of the type 1 interferon pathway in BD, IIM and IgG4-RD, inhibition of the Janus kinase (JAK) STAT pathway emerges as a promising therapeutic strategy. The Drug Rediscovery in IMIDs (DRIMID) consortium aims to conduct a prospective pilot basket trial to investigate the effects of filgotinib, a JAK1 preferential inhibitor approved for ulcerative colitis and rheumatoid arthritis, on disease activity, quality of life and safety in patients with refractory BD, IIM and IgG4-RD.

METHODS AND ANALYSIS

In this investigator-initiated, multicentre, open-label phase 2 study, up to 60 patients with rare IMIDs will be enrolled for a 26-week treatment period with filgotinib 200 mg once daily. The trial consists of two stages, each involving a consecutively treated cohort of up to 20 patients per disease. An interim analysis is conducted between these stages, where the trial will proceed only in diseases showing potential effectiveness. Baseline, 3-month and 6-month assessments will include data on quality of life, disease activity, corticosteroid toxicity and biomarkers. The coprimary endpoints are disease activity and quality of life across and within each disease.

ETHICS AND DISSEMINATION

The study received approval from the Medical Research Ethics Committee in Utrecht, Netherlands. A Data Safety Monitoring Board has been established to monitor the trial's safety and progress.

TRIAL REGISTRATION NUMBER

NCT06285539.

Update on Autoimmune Pancreatitis and IgG4-Related Disease

Autoimmune pancreatitis is an increasingly recognized inflammatory type of subacute pancreatitis; two subtypes of autoimmune pancreatitis have been identified so far: the "lymphoplasmacytic" type 1 variant and the "neutrophilic" type 2 variant. Type 1 autoimmune pancreatitis represents the most common manifestation of IgG4-related disease, a fibro-inflammatory disorder characterized by elevated IgG4 levels in the serum and affected tissues. Type 2 autoimmune pancreatitis is a pancreas-specific disorder that frequently occurs in the context of inflammatory bowel diseases. Due to the complexity of both diseases, a comprehensive work up with imaging, laboratory, and histological studies is required to achieve a diagnosis and rule out malignancies. Glucocorticoids represent the cornerstone of the treatment, often supported by other immunosuppressive drugs in case of steroid intolerance or aggressive disease. Maintenance treatment is often employed in type 1 autoimmune pancreatitis because of the higher relapse rate compared with type 2 autoimmune pancreatitis. In this review, we summarize the key concept of autoimmune pancreatitis, delve into the differential diagnosis between the two subtypes, and cover the recent relevant research findings and pressing unmet needs.

Exploring cardiovascular involvement in IgG4-related disease: a case series approach with cardiovascular magnetic resonance

BACKGROUND

IgG4-related disease (IgG4-RD) is a relapsing-remitting, fibroinflammatory, multisystem disorder. Cardiovascular involvement from IgG4-RD has not been systematically characterised. In this study, we sought to evaluate consecutive patients with IgG4-RD using a detailed multiparametric cardiovascular magnetic resonance (CMR) imaging protocol.

METHODS

We prospectively enrolled 11 patients with histology-confirmed IgG4-RD; with active disease at time of scan. We undertook a detailed multiparametric CMR imaging protocol at 1.5T including cine imaging, native T1 and T2 mapping, stress perfusion imaging with inline quantitation of myocardial blood flow and late gadolinium enhancement (LGE) imaging.

RESULTS

All patients exhibited at least one abnormality on CMR imaging. Abnormal elevation of global or segmental left ventricular myocardial T1 and T2 values was present in four patients, suggesting myocardial oedema or inflammation. Abnormal LGE, suggesting myocardial scar fibrosis, was present in nine patients, with eight displaying a non-ischaemic pattern, and one showing an ischaemic pattern. Four patients fulfilled both Lake Louise Criteria for active myocardial inflammation, while a further six fulfilled one criterion. Myocardial perfusion reserve was normal in all evaluable patients. Ten patients had normal ventricular volumes, mass and systolic function. In addition, thoracic aortitis was identified in three patients who underwent 18F-flourodeoxyglucose PET/CT imaging, with resolution following anti-B-cell treatment.

CONCLUSIONS

In this cohort of patients with histology-confirmed IgG4-RD, multiparametric CMR revealed no changes in gross cardiac structure and function, but frequent myocardial tissue abnormalities. These data suggest a plausible pathophysiological link between IgG4-RD and cardiovascular involvement.

Coexistence of immunoglobulin G4-related kidney disease and acute hematogenous disseminated pulmonary tuberculosis: a case report

Background

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibrous inflammatory disease. Recently, an association between IgG4-RD and tuberculosis (TB) has been reported.

Case summary

We report a 56-year-old man complaining of a cough and poor appetite for 2 months and oliguria for 1 day. The patient was diagnosed with TB due to a manifestation of lymphatic TB and the radiological alterations of acute miliary pulmonary TB. He also presented with greatly elevated serum creatinine, non-albumin proteinuria, immunoglobulin subgroup IgG4, and immunoglobulin free light chain (FLC) levels. A diagnosis of IgG4-RKD was suggested by a renal biopsy. We then administered the patient glucocorticoid and anti-TB treatment for 4 months. The patient's renal function was completely restored and the manifestations of TB were alleviated.

Conclusion

The necessity and complexity of differential diagnosis in patients with coexisting IgG4-RD and TB remains challenging. Early recognition and timely treatment are important for averting its progression. Long-term monitoring is required to assess for recurrence of IgG4-RD and TB activity.

IgG4-related disease mimicking a liver abscess

IgG4-related disease (IGRD) is a complex medical condition affecting multiple organs, including the liver. The condition is characterized by excessive production of IgG4 antibodies, leading to chronic inflammation and tissue damage. We present a case of a 37-year-old man with a history of chronic pancreatitis was diagnosed with a liver mass. Initial treatment included piperacillin and tazobactam, but the patient's condition worsened. An ultrasound-guided biopsy revealed increased IgG4 positive cells, leading to the diagnosis of an inflammatory pseudotumor associated with IGRD. The patient was treated with prednisone taper therapy, and the liver mass resolved after six months of corticoid treatment.

Omics in IgG4-related disease

ABSTRACT

Research on IgG4-related disease (IgG4-RD), an autoimmune condition recognized to be a unique disease entity only two decades ago, has processed from describing patients' symptoms and signs to summarizing its critical pathological features, and further to investigating key pathogenic mechanisms. Challenges in gaining a better understanding of the disease, however, stem from its relative rarity-potentially attributed to underrecognition - and the absence of ideal experimental animal models. Recently, with the development of various high-throughput techniques, "omics" studies at different levels (particularly the single-cell omics) have shown promise in providing detailed molecular features of IgG4-RD. While, the application of omics approaches in IgG4-RD is still at an early stage. In this paper, we review the current progress of omics research in IgG4-RD and discuss the value of machine learning methods in analyzing the data with high dimensionality.

Sino-Orbital IgG4 Related Disease- An Uncommon Entity

IgG4 related disease (IgG4-RD) is an auto immune fibro-inflammatory condition, characterised by presence of IgG4 positive lymphoplasmacytic infiltrates and extensive fibrosis of the involved organ. It commonly affects pancreas, biliary tract and salivary glands. Sino-orbital involvement is a relatively rare presentation. There is extensive fibrosis of the involved organ. Biopsy is often diagnostic and it shows extensive necrosis and lymphoplasmocytic infiltrates. They show dramatic response to steroid therapy. Here we present three cases of IgG4-RD disease involving orbit and para nasal sinuses who were evaluated and treated in a tertiary care teaching hospital over a period of 2 years.

Fibrotic phenotype of IgG4-related disease

A prompt response to glucocorticoids is a clinical hallmark of IgG4-related disease. However, manifestations characterised by prominent tissue fibrosis on histological examination can be less responsive to glucocorticoid therapy than other types of IgG4-related disease. These manifestations include retroperitoneal fibrosis, fibrosing mediastinitis, Riedel thyroiditis, orbital pseudotumor, and hypertrophic pachymeningitis, among others. To explain this discrepancy, a preliminary distinction into proliferative and fibrotic phenotypes of IgG4-related disease has been proposed on the basis of clinical presentation, pathological features, and response to immunosuppressive therapy. Implications of this classification for patient management remain an important area of investigation. In this Series paper, we aim to dissect the pathophysiology of tissue fibrosis in IgG4-related disease and discuss how clinicians should approach the management of fibrotic manifestations of IgG4-related disease based on the most recent diagnostic and therapeutic developments.

Challenges and pitfalls in the diagnosis of IgG4-related disease

IgG4-related disease (IgG4-RD) is a relatively novel fibroinflammatory condition characterized typically by dense lymphoplasmacytic inflammation, storiform fibrosis and obliterative venulitis, together with prominent IgG4+ plasma cells and an IgG4+/IgG+ plasma cell ratio of >40 %. The diagnosis is usually made on a combination of clinical and serological features together with characteristic radiological and histological appearances. The condition may be limited to a single tissue/organ (e.g., autoimmune pancreatitis) or may be multicentric in nature - four clinical 'patterns' of disease distribution have recently been described. The diagnosis of IgG4-RD can be challenging, particularly when the clinical presentation is unusual and/or when the histological features are not typical. A diagnosis of IgG4-RD may still be achieved in these situations, after careful clinicopathological discussion e.g., at a specialist multidisciplinary team meeting. However, a wide range of other conditions (neoplastic and non-neoplastic) can mimic IgG4-RD, clinically and/or on histological examination. The relationship between IgG4-RD and non-IgG4-RD associated conditions in some clinical situations is particularly complex. This review describes the role of histological examination in the diagnosis of IgG4-RD, discusses some of the practical difficulties that may be encountered and provides an insight into the range of non-IgG4-RD associated conditions that can mimic IgG4-RD on clinical and/or histological grounds. The requirement for interpretation of histological features in the context of the global clinical picture of the patient is highlighted and emphasized.

Enfermedad relacionada con inmunoglobulina G4, un diagnóstico a tener en cuenta: a propósito de un caso

La enfermedad relacionada con inmunoglobulina G4 (ER-IgG4) es una condición inmunomediada y multisistémica asociada al desarrollo de lesiones fibroinflamatorias en cualquier órgano. El diagnóstico se realiza bajo la suma de criterios clínicos, serológicos, radiológicos e histopatológicos; sin embargo, este suele ser difícil debido a su similitud con neoplasias, infecciones u otras enfermedades inmunomediadas. El tratamiento se basa en corticosteroides, en una posible combinación con inmunomoduladores. El presente caso trata de un varón de 59 años con historia de síndrome ictérico y baja de peso, admitido por sospecha de neoplasia maligna de la vía biliar. Las imágenes revelaron estenosis con dilatación de las vías biliares intrahepáticas, páncreas prominente, estenosis del conducto pancreático y lesiones nodulares renales. Debido al antecedente de submandibulectomía izquierda 2 años antes de la enfermedad actual e histología compatible con tumor de Küttner, más los valores elevados de IgG4 sérico, se estableció el diagnóstico de ER-IgG4. Inició tratamiento con corticosteroides y cursó asintomático durante el seguimiento.

The spectrum of B cells in the pathogenesis, diagnosis and therapeutic applications of immunoglobulin G4-related disease

Immunoglobulin G4 (IgG4)-related disease is a chronic fibroinflammatory disease mediated by immune disorders. Given the challenging clinical diagnosis and treatment, knowledge of the pathogenesis of IgG4-related disease is important. The typical elevation of serum IgG4 concentrations and infiltration of IgG4-positive plasma cells in the involved tissues indicate the involvement of B lymphocytes in the pathogenesis of IgG4-related disease. Mass production of autoantibodies reflects abnormal activation of B cells, which causes tissue damage. Circulating plasmablasts are recently discovered markers that correlate with serum IgG4 concentration, the extent of organ involvement and disease activity. B-cell depletion therapy is an emerging curative strategy that can significantly alleviate clinical manifestations and achieve remission in patients with IgG4-related disease. These findings highlight the potential role of B cells in IgG4-related disease. In this review, we discuss the pathogenic impact of B lymphocytes on IgG4-related disease and describe novel therapies targeting B cells.

IgG4-related digestive diseases: diagnosis and treatment

IgG4-related digestive diseases encompass a group of chronic inflammatory disorders characterized by autoimmune reactions and fibrosis affecting multiple digestive organs. These diseases are identified by elevated serum levels of IgG4 and the presence of IgG4-positive plasma cell infiltration in the affected sites, along with storiform fibrosis, obliterative phlebitis, and eosinophilic infiltration. Although extensive research has been conducted, a comprehensive understanding of these conditions remains elusive. Current clinical diagnosis often relies on the application of integrated diagnostic criteria for IgG4-related diseases, combined with specific organ involvement criteria. Distinguishing them from malignancies poses considerable challenges. Moreover, further investigations are required to elucidate the underlying pathogenic mechanisms and explore potential therapeutic interventions. This review provides a systematic classification of IgG4-related digestive diseases while discussing their diagnostic strategies, clinical presentations, and treatment modalities. The comprehensive insights shared herein aim to guide clinicians in their practice and contribute to the advancement of knowledge in this field.

Coronary artery ectasia associated with IgG4-related disease: a case report and literature review

BACKGROUND

Coronary artery ectasia is defined as a local or diffuse dilatation of the coronary artery more than 1.5 times the diameter of the adjacent normal segment. The etiology of coronary artery ectasia is diverse, and rarely complicated with immunoglobulin G4-related disease (IgG4-related disease). A limited number of cases have been reported, with insidious onset, slow progression but poor prognosis.

CASE PRESENTATION

we report a patient with coronary artery ectasia combined with IgG4-related disease. He has been diagnosed with IgG4-related disease 5 years after his first percutaneous coronary intervention (PCI). Despite routine treatment with steroids, he develops a large coronary aneurysm and eventually died.

CONCLUSIONS

It is suggested that a thorough evaluation should be performed when coronary artery ectasia is diagnosed. The factors such as manifestations of coronary artery thickening, typical imaging features, other aortas involvement, increased serum IgG4 level, etc. should be considered for early diagnosis of key etiologies.

B-Cell depletion therapy in IgG4-related disease: State of the art and future perspectives

IgG4-related disease (IgG4-RD) is an increasingly recognized immune-mediated fibroinflammatory disorder that promptly responds to glucocorticoids but commonly relapses during steroid tapering or after discontinuation. In the last few years, B-cell depletion therapy with rituximab (RTX) proved to be effective in the induction of remission and maintenance treatment of IgG4-RD, providing a new powerful tool in the management of this emerging condition. In this review, we outline the pathogenetic rationale for using B-cell depleting agents in IgG4-RD, we summarize available clinical experience with RTX in this disease, and we describe future possible therapies targeting B-lymphocytes that are now in the pipeline.

Perspectives on current and emerging therapies for immunoglobulin G4-related disease

Understanding of the pathophysiology of immunoglobulin G4-related disease (IgG4-RD) over the last dozen years has opened the door to a variety of targeted treatment approaches. Glucocorticoids are an effective treatment for IgG4-RD if used at a sufficiently high dose, but disease flares are common during or after glucocorticoid tapers and these medications seldom lead to long-term, treatment-free remissions. Moreover, their long-term use in a disease that frequently affects middle-aged to elderly individuals and often causes major pancreatic damage leads to a narrow therapeutic index. Biological therapies offer the possibility of effective disease control with fewer treatment-associated side effects. Promising avenues of investigation include B-cell depletion, immunomodulation of B-cell subsets, interference with co-stimulation, Bruton's tyrosine kinase inhibition, and Signaling lymphocytic activation molecule F7-directed treatment.

Orbital Proptosis and Sinusitis in a Middle-aged Woman

A 48-year-old woman presented with 3 days of worsening right orbital swelling, eye pain, blurry vision, and 3 months of bilateral photophobia, with rhinorrhea, congestion, and headaches. What is your diagnosis?

Development of an algorithm for IgG4-related disease management

OBJECTIVES

IgG4-related disease (IgG4-RD) is a rare fibro-inflammatory condition affecting multiple organs lacking standardized management. In this article, we review the evidence available to provide European expert-based statements on the management of IgG4-RD which were integrated in a final algorithm.

METHODS

A panel of nine European experts in IgG4-RD from different specialties was asked to elaborate a set of consensus statements through a Delphi exercise. Three rounds of survey were taken. Consensus was reached when ≥75% of the responders agreed with a statement.

RESULTS

Thirty-one statements on induction treatment, maintenance treatment, non-pharmacological treatment, and general considerations were assessed. Patients should be treated promptly in situations when there is an immediate organ threatened, or when organ damage is anticipated. Glucocorticoids (GC) are considered the first line of treatment and should be progressively tapered. Maintenance treatment is recommended for patients with high disease activity or with risk factors for relapse. Rituximab is effective for induction and maintenance of remission, but its use can be limited by economics. Low dose GC with or without GC-sparing agents can be used for maintenance therapy. Stenting or surgery should be ancillary to pharmacological treatment. Follow up should be based on physical examination, blood works, and imaging studies. Furthermore, it should be tailored on individual patient clinical history. 18-fluorodeoxyglucose positron emission tomography/computerized tomography may provide additional information over other imaging modalities.

CONCLUSIONS

These new statements and algorithm reached a high degree of agreement and may help guiding the clinical management of IgG4-RD.

Bibliometric analysis of IgG4-related disease research from 2003 to 2022 based on Web of Science Core Collection Databases

This study aimed to perform a bibliometric analysis of the IgG4-related disease (IgG4-RD) research field over the past 20 years to explore its research hotspots and trends. The literature of IgG4-RD published in the Web of Science Core Collection databases was reviewed from January 1, 2003, to April 30, 2022. A bibliometric analysis was carried out using CiteSpace software to evaluate and visualize the evolving dynamics and hotspots in the field of IgG4-RD. A total of 3174 IgG4-RD articles were reviewed. Since 2011, there has been a rapid increase in published literature. Japan is the highest yielding country and Kanazawa University the highest yielding institution. The USA has the highest centrality (0.34) and plays a critical role in cooperation and communication of IgG4-RD research. Nine highly connected clusters of IgG4-RD were observed by keyword analysis. Research hotspots included IgG4-RD involved organs and differentiation from Rosai-Dorfman disease and primary sclerosing cholangitis. Further research topics include pathogenesis, relapse, and malignancy. As a cross-discipline systemic disease, IgG4-RD requires attention by clinicians in multiple fields. This bibliometric analysis can help researchers grasp trends and provide new perspectives for future research on IgG4-RD.

Potential roles of non-lymphocytic cells in the pathogenesis of IgG4-related disease

Studies have confirmed the involvement of a variety of lymphocyte subsets, including type 2 helper T lymphocytes (Th2) and IgG4+ B lymphocytes, in the pathogenesis of IgG4-related disease (IgG4-RD). Those lymphocytes contribute to the major pathogenetic features of IgG4-RD. However, they are not the only cellular components in the immunoinflammatory environment of this mysterious disease entity. Recent studies have suggested that various non-lymphocytic components, including macrophages and fibroblasts, may also play an important role in the pathogenetic process of IgG4-RD in terms of contributing to the chronic and complex progress of the disease. Therefore, the potential role of non-lymphocyte in the pathogenesis of IgG4-RD is worth discussing.

Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study

Background

IgG4 is associated with two emerging groups of rare diseases: 1) IgG4 autoimmune diseases (IgG4-AID) and 2) IgG4-related diseases (IgG4-RLD). Anti-neuronal IgG4-AID include MuSK myasthenia gravis, LGI1- and Caspr2-encephalitis and autoimmune nodo-/paranodopathies (CNTN1/Caspr1 or NF155 antibodies). IgG4-RLD is a multiorgan disease hallmarked by tissue-destructive fibrotic lesions with lymphocyte and IgG4 plasma cell infiltrates and increased serum IgG4 concentrations. It is unclear whether IgG4-AID and IgG4-RLD share relevant clinical and immunopathological features.

Methods

We collected and analyzed clinical, serological, and histopathological data in 50 patients with anti-neuronal IgG4-AID and 19 patients with IgG4-RLD.

Results

A significantly higher proportion of IgG4-RLD patients had serum IgG4 elevation when compared to IgG4-AID patients (52.63% vs. 16%, p = .004). Moreover, those IgG4-AID patients with elevated IgG4 did not meet the diagnostic criteria of IgG4-RLD, and their autoantibody titers did not correlate with their serum IgG4 concentrations. In addition, patients with IgG4-RLD were negative for anti-neuronal/neuromuscular autoantibodies and among these patients, men showed a significantly higher propensity for IgG4 elevation, when compared to women (p = .005). Last, a kidney biopsy from a patient with autoimmune paranodopathy due to CNTN1/Caspr1-complex IgG4 autoantibodies and concomitant nephrotic syndrome did not show fibrosis or IgG4+ plasma cells, which are diagnostic hallmarks of IgG4-RLD.

Conclusion

Our observations suggest that anti-neuronal IgG4-AID and IgG4-RLD are most likely distinct disease entities.

Update on classification, diagnosis, and management of immunoglobulin G4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized chronic fibro-inflammatory autoimmune disease, and its recognition has been constantly increasing worldwide over the last few years. A correct and timely recognition, as well as appropriate intervention, is crucial for the treatment of IgG4-RD. For certain subtypes of IgG4-RD, organ-specific criteria are formulated to make the diagnosis more accurate. New biomarkers have emerged in the recent years to aid the disease diagnosis, its prognosis prediction, as well as therapy response monitoring. Although recurrence is very common in IgG4-RD, glucocorticoid is still the first-line treatment for the majority of patients. The factors that affect the likelihood of disease relapse are multifaceted. The selection strategy of various steroid-sparing agents is still being explored. Besides, when patients have special sites involvement leading to severe clinical conditions, surgical operation or interventional therapy should also be considered. An update on classification, diagnosis, and management of IgG4-RD is provided in the current study to fully elucidate the recommended clinical practice of this mysterious disease.

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.

Immunoglobulin G4-related lymph node disease with an orbital mass mimicking Castleman disease: A case report

BACKGROUND

Immunoglobulin (Ig) G4-associated diseases are a group of systemic diseases involving multiple organs and are also known as IgG4-associated sclerosing diseases. IgG4-associated lymphadenopathy occurring in the lymph nodes is characterized by a lack of specificity due to its clinicopathological characteristics and must be differentiated from a variety of lesions, such as Castleman disease, lymphatic follicular reactive hyperplasia, and lymphoma.

CASE SUMMARY

A 65-year-old male patient, with Guillain-Barre syndrome for 5 years, presented to our hospital complaining of bilateral orbital mass for 2 years. After hospitalization, the results of the patient’s laboratory tests showed that immunoglobulin subgroup IgG4 was 33.90 g/L and IgG was 30.30 g/L, but serum interleukin-6 was normal. The pathological morphology of orbital mass and cervical lymph node were consistent, which showed that a large number of plasma cells and eosinophils were observed in the lymphatic follicles, and the interstitial fibrous tissue was proliferative. Immunohistochemistry showed that CD20 (B cells) (+), CD3 (T cells) (+), CD38 (+), IgG (+), IgG4 positive cells > 100/high powered field, and IgG4/IgG > 40%. Combined with clinical and immunohistochemical results, lymphadenopathy was consistent with Castleman disease-like IgG4-associated sclerosing disease. Prednisone acetate treatment was given at 40 mg/d. After 2 wk, the superficial lymph nodes and orbital masses shrank, and the IgG4 level decreased. As prednisone acetate was regularly used at a reduced dosage, no recurrence of the disease has been observed.

CONCLUSION

This case suggested that it is necessary to proceed cautiously in clinical practice with such patients, and immunoglobulin, complement, interleukin-6, C-reactive protein, and other examinations should be performed to confirm the diagnosis.

Clinical Perspectives on IgG4-Related Disease and Its Classification

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease. Since its discovery nearly two decades ago, our understanding of its pathophysiology and clinical manifestations has grown substantially. Early diagnosis and treatment of this elusive disease can prevent substantial organ damage from end-stage fibrosis, emphasizing the need for prompt recognition and accurate characterization of IgG4-RD. The classification criteria endorsed by the American College of Rheumatology and the European Alliance of Associations for Rheumatology in 2019 provide a framework for establishing the diagnosis in the clinical setting. This process involves recognizing the typical manifestations of the disease and incorporating clinical, radiological, serological, and histopathological information as well as excluding disease mimickers. Glucocorticoids and rituximab are effective at inducing remission in IgG4-RD in most patients, but the optimal approach to long-term management of IgG4-RD remains an area of active clinical research. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.