The Clinicopathologic Spectrum of IgG4-Related Disease

IgG4 in the gut: Gastrointestinal IgG4-related disease or a new subtype of inflammatory bowel disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory condition characterized by tissue infiltration with IgG4-positive plasma cells, leading to fibrosis and organ dysfunction. While primarily affecting the pancreas, bile ducts, and salivary glands, IgG4-RD can also involve the gastrointestinal tract, raising questions about its relationship with inflammatory bowel disease (IBD). Recent studies suggest that patients with IBD may exhibit histological and serological features consistent with IgG4-RD, such as a dense lymphoplasmacytic infiltration, a storiform-type of fibrosis and a prominent IgG4 immune response. This overlap represents a diagnostic challenge, as differentiating between primary IBD and IgG4-RD involving the gut is crucial for appropriate treatment. Further research is essential to delineate the prevalence of tissue and serum IgG4 expression in patients with IBD. This approach could classify subtypes of IBD, enabling advancements in non-invasive diagnosis and monitoring as well as personalized therapies. The purpose of this review is to summarize the available evidence regarding intestinal involvement in IgG4-RD and the role of both serum and tissue IgG4 in inflammatory bowel diseases IBD.

T Cell Roles and Activity in Chronic Sclerosing Sialadenitis as IgG4-Related Disease: Current Concepts in Immunopathogenesis

IgG4-related disease is a multiorgan immunological fibroinflammatory disorder characterized by lymphoplasmacytic infiltration and fibrosis in multiple organs accompanied by high serum IgG4 levels. The salivary glands are the most common organs involved in this disease. Recently, chronic sclerosing sialadenitis affecting salivary glands, formerly known as Küttner's tumor, and Mikulicz's disease have been classified as a class of IgG4-related diseases. The etiopathobiology of IgG4-related disease is not fully understood. It has recently been hypothesized that the inflammatory and fibrotic process and the increased serum IgG4⁺ levels in IgG4-related disease are the result of an interaction between B cells and T helper cells, suggesting that T cells may play a key role in the pathogenesis of this disease. The aim of this review is to discuss the proposed roles of different T cell subsets in the pathogenesis of IgG4-related disease focusing on their roles in immunopathogenesis of IgG4-related sialadenitis.

A rare case of IgG4-related disease masquerading as periurethral malignancy and review of the literature

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease that typically manifests as mass lesions affecting almost any organ including the pancreas, lacrimal and salivary glands, liver, lung and kidney. However, IgG4-RD with urethra involvement is scarce. We describe a rare case of IgG4-RD involving the urethra mimicking urethral carcinoma and review the published literature. A 64-years-old female presented with progressive dysuria for more than 2 months. Pelvic gadolinium-enhanced magnetic resonance imaging revealed a huge mass encasing the urethra which showed obvious enhancement in the arterial phase. And contrast-enhanced ultrasound showed that the entire mass was heterogeneously enhanced and displayed a fast-forward and fast-out pattern, which was highly suggestive of malignant tumor. The diagnosis of IgG4-RD was finally established by ultrasound-guided transvaginal mass needle biopsy. The patient was treated with methylprednisolone and cyclophosphamide and dysuria disappeared in the first week of therapy. She has been followed up in our clinic for 1 year without recurrence. The diagnosis of IgG4-RD should be considered in the differential diagnosis of a periurethral mass. Ultrasound-guided transvaginal mass needle biopsy is a safe and well-established tissue sampling method and should be performed in order to avoid unnecessary surgery.

Recurrent Pleural Effusions, Lymphedema, and Abnormal Nails in a 61 Year Old Man

A 61 year old man with history of hypertension, coronary artery disease (CAD) with prior stent placement, and chronic obstructive pulmonary disease (COPD) presented with a four month history of recurrent pleural effusions and progressive diffuse edema. Four months prior to hospital presentation, the patient began to notice new onset dyspnea on exertion, fatigue, and chest pain. Initial evaluation with troponin and EKG were negative. A chest x-ray (CXR) was done which revealed a moderate sized left pleural effusion. He did not have a history of pleural effusions or heart failure. Therefore, he underwent diagnostic thoracentesis and fluid studies were consistent with an exudative pleural effusion without malignant cells or microbial growth.

IgG4 Related Kidney Disease with Extra-Renal Involvement Demonstrated on FDG PET/CT

Immunoglobulin G4 (IgG4)-related kidney disease is a relatively rare clinical entity and usually occurs as an extra-pancreatic manifestation of IgG4-related autoimmune pancreatitis. We describe here the imaging findings of a patient who presented with recurrent multiorgan IgG4-related disease, involving bilateral kidneys/ureters, proximal small bowel, and multiple abdominal and extra-abdominal lymph nodes.

[IgG4-associated lung disease with granulomatous lesions : Coexistence of two entities or the spectrum of one disease?]

A 54-year-old patient with a history of pulmonary tuberculosis and occupational exposure to dust in early adulthood presented with symptoms of coughing with sputum, weight loss, occasional night sweats, and thoracic pain. Non-necrotizing granulomatosis in lung and lymph-node biopsies indicated sarcoidosis. Combined immunosuppressive therapy did not lead to an improvement. An atypical lung resectate with fibroinflammatory changes and obliterative endothelialitis may finally lead to the diagnosis of IgG4-associated lung disease with a bronchovascular pattern of involvement. The question discussed here is whether this is a coexistence of IgG4-associated lung disease with sarcoidosis or the spectrum of one disease.

[IgG4-Related Orbitopathy as an Important Differential Diagnosis of Advanced Silent Sinus Syndrome. German version]

Hintergrund

Mit Immunglobulin (Ig)G4 assoziierte Erkrankungen werden als immunvermittelte Erkrankungen klassifiziert. Die Ätiologie dieser Krankheiten ist bisher noch nicht geklärt. Sie manifestieren sich auf verschiedene Weise, und die gleichzeitige Beteiligung mehrerer Organe ist nicht ungewöhnlich.

Kasuistik

Es wird der Fall eines Patienten vorgestellt, der in die Klinik der Autoren überwiesen wurde, nachdem mehrere erfolglose Nasennebenhöhlenoperationen bei ihm durchgeführt worden waren; bei Vorliegen eines Enophthalmus und einer resultierenden Durchwanderungskeratitis bestand die Verdachtsdiagnose eines Silent-Sinus-Syndroms. Der Erhalt der Orbita war nicht mehr möglich. Nach 5 Jahren ohne definitive Diagnose wurde nun die Diagnose einer IgG4-assoziierten Erkrankung gesichert.

Diskussion

IgG4-assoziierte Erkrankungen stellen einen wichtigen Baustein bei der Differenzialdiagnose chronischer fortgeschrittener Erkrankungen der Orbita und der Nasennebenhöhlen dar. Bei unklaren Krankheitszeichen sollte diese Diagnose in Erwägung gezogen werden. Zu den typischen histologischen Befunden gehören ein storiformes Muster der Fibrose, Vaskulopathie und Gewebeinfiltration durch IgG4-Plasmazellen.

Immunoglobulin G4-related Disease of the Genitourinary System: Spectrum of Imaging Findings and Clinical-Pathologic Features

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by focal or diffuse organ infiltration of IgG4-bearing plasma cells. The diagnosis of IgG4-RD is based on a combination of clinical, serologic, radiologic, and histopathologic findings. IgG4-RD has been reported to affect almost all organ systems. The kidney is the most frequently involved of the genitourinary organs. The most common renal manifestation of IgG4-RD is IgG4-RD tubulointerstitial nephritis, followed by membranous glomerulonephropathy and, less frequently, obstructive nephropathy involving the renal pelvis, ureter, or retroperitoneum. Renal parenchymal lesions may appear as multiple nodular lesions, diffuse patchy infiltrative lesions, or a single nodular lesion. Multiple small nodular cortical lesions are the most common imaging findings of IgG4-RD involving the kidney. Renal pelvic, sinus, or perinephric lesions can also occur. IgG4-RD involvement of other genitourinary organs including the ureter, bladder, urethra, and male and female reproductive organs is rare compared with kidney involvement but may show variable imaging findings such as a localized mass within or surrounding the involved organ or diffuse enlargement of the involved organ. Imaging findings of IgG4-RD involving the genitourinary system are nonspecific but should be differentiated from inflammatory and neoplastic lesions that mimic IgG4-RD. The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2020.

Inflammatory choroidal neovascularization associated with immunoglobulin G4-related disease: a case report

Background

Immunoglobulin G4-related disease is a recently recognized condition with pathologic features that are consistent across a wide range of organ systems. Orbital manifestations of this disease entity typically involve the lacrimal gland and lacrimal duct, extraocular muscles, orbital soft tissue, and sclera. Here, the authors report the first known case of inflammatory choroidal neovascular membrane associated with immunoglobulin G4-related disease and offer suggestions for clinical management of this enigmatic condition.

Case presentation

A 38-year-old Caucasian man with a history of recurrent tonsillitis presented with blurry vision in his left eye of 1-week duration and was diagnosed as having inflammatory choroidal neovascular membrane. An infectious workup was negative, but his serum immunoglobulin G4 level was elevated at 248 mg/dL (reference 4–86), and a subsequent tonsillectomy for a repeat episode of tonsillitis revealed increased immunoglobulin G4 staining on histopathology, thus confirming the diagnosis of immunoglobulin G4-related disease. The inflammatory choroidal neovascular membrane was treated with intravitreal bevacizumab injections and orally administered prednisone resulting in improved visual acuity and choroidal neovascular membrane regression. He later received rituximab infusions for immunoglobulin G4-related disease.

Conclusions

We report a case of choroidal neovascularization associated with immunoglobulin G4-related disease, a chronic inflammatory condition whose ophthalmic manifestations typically include dacryoadenitis, orbital myositis, or scleritis. This is the first reported instance of inflammatory choroidal neovascular membrane associated with immunoglobulin G4-related disease. Early detection of this disease is important to avoid organ damage and potential complications, so clinicians should maintain an index of suspicion for this condition when inflammatory choroidal neovascular membrane is observed.

IgG4 sclerosing disease of the esophagus: a case-based review

IgG4-related disease (IgG4-RD) is an inflammatory and fibrosing disease which causes tumor-like swelling of organs and commonly mimics symptoms of malignancy. It has been increasing in prevalence in the last decade, but esophageal involvement remains rare. IgG4-RD was first known to involve certain organs, such as the pancreas. It has, since, been described as a systemic disease process. IgG4-RD should be considered in patients presenting with dysphagia. Initiation of appropriate treatment with corticosteroids can avoid unnecessary procedures and improve outcomes. The aim of this review is to discuss 17 cases of IgG4-RD of the esophagus. Literature review was conducted using NCBI database (PMC and PubMed filters) using the keywords "IgG4 disease," "sclerosing," "esophagus" and "gastrointestinal." The search was narrowed to include cases describing IgG4 disease of the esophagus using the same filters. Literature review identified 16 documented cases of IgG4-RD involving the esophagus. Upon literature review, it remains clear that it is extremely rare for IgG4-RD to affect the esophagus. Sixteen cases have been reported. We present a 17th case and discuss the implications of IgG4-RD. It is important to keep a broad differential diagnosis that includes IgG4-RD for patients presenting with dysphagia, especially when symptoms are refractory.

IgG4-related orbitopathy as an important differential diagnosis of advanced silent sinus syndrome

BACKGROUND

Immunoglobulin (Ig)G4-related disease is classified as an immune-mediated disease. The etiology of this condition has not been explained to date. Manifestations of the disease are diverse, and simultaneous involvement of multiple organs is not unusual.

CASE REPORT

We report the case of a patient referred to us after multiple unsuccessful paranasal sinus operations who presented with enophthalmos and a resultant migratory keratitis with a suspected diagnosis of silent sinus syndrome. Preservation of the orbit was no longer feasible. After five years without a definitive diagnosis, we ascertained that this was a case of IgG4-related disease.

DISCUSSION

IgG4-related disease represents an important element in the differential diagnosis of chronic advanced diseases of the orbit and paranasal sinuses. The diagnosis should be considered in the case of unclear disease presentations. Typical histological findings include a storiform pattern of fibrosis, vasculopathy, and tissue infiltration by IgG4 plasma cells.

B Cell-Mediated Autoimmune Diseases

Extensive studies have suggested a central role of B cells in the autoimmune pathogenesis, as loss of B cell tolerance results in increased serum levels of autoantibodies, enhanced effector T cell response and tissue damages. Here, we provide an overview of dysregulated B cell responses in the development of autoimmunity. In addition to their presence in the target organs, autoreactive B cells can promote the formation of ectopic lymphoid structures and differentiate into plasma cells that produce large amounts of autoantibodies and cytokines. In animal models that recapitulate the key features of human autoimmune disease, mechanistic studies have indicated two categories of autoantibodies: (1) serological markers for disease diagnosis and prognosis; (2) effector molecules that induce organ hypofunction or damage directly in an epitope-specific manner, or indirectly by activating other immune cell subsets. Moreover, B cell-derived cytokines usually promote the autoreactive T cell response during autoimmune development, but there is compelling evidence that a subpopulation of B cells negatively regulates immune responses, also known as regulatory B cells via secreting anti-inflammatory cytokines (IL-10, IL-35, etc.) or a contact-dependent fashion. Although B cell depletion could eliminate most circulating B cells in the periphery, the clinical outcomes of B cell depletion therapy for autoimmune diseases vary among individuals due to differential activation or survival signals for B cells provided by tissue microenvironment. Thus, therapeutic combinations that target immune checkpoints and B cell activation may represent a promising strategy for the effective treatment of human autoimmune diseases.

Pancreatitis, Cholangitis, and Gastritis: The Triumvirate of Immunoglobulin G4-Related Disease Identified Simultaneously on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Immunoglobulin G4-related disease (IgG4) is an immune-mediated fibro-inflammatory entity which affects multiple organs, most frequently the pancreas. Although extrapancreatic inflammations are commonly seen in ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography of majority of these patients at follow-up, simultaneous involvement of the gastric/biliary tract at presentation is rare. Here, we present imaging findings of a patient who presented with obstructive jaundice and initially thought to be due to cholangiocarcinoma, but was subsequently diagnosed as an IgG4-related inflammation.