The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4‐Related Disease

IgG4-related disease presenting with profound bilateral orbital and adnexal inflammation

Purpose

IgG4-related disease is an immune-mediated fibroinflammatory condition that can affect almost every major organ system. Orbital and adnexal involvement in IgG4-related disease though not uncommon can be varied depending on the site of the lymphoplasmacytic infiltration. This case of profound bilateral orbital inflammation is presented to demonstrate the significant clinical manifestations of IgG4-related ophthalmic disease.

Observations

A 52-year-old man with a remote and seemingly unrelated history of lymphadenopathy presented to the Oculoplastics clinic with massive bilateral upper and lower lid swelling and induration. Hematologic testing demonstrated an elevation in serum IgG4 - a non-specific finding seen in various infectious, inflammatory, and malignant processes. Imaging demonstrated diffuse enlargement of orbital structures, including the lacrimal glands and extraocular muscles, as well as inflammatory changes of the adnexal and retrobulbar soft tissue. Orbital biopsy was required to confirm the diagnosis of IgG4-related ophthalmic disease.

Conclusions and Importance

IgG4-related ophthalmic disease presents with various non-specific clinical signs and symptoms. The most common presentations include dacryoadenitis, enlarged orbital nerves, and orbital fat involvement; however, the extent of involvement both locally and systemically varies greatly. Clinical findings and imaging are helpful in narrowing the differential diagnosis; however, biopsy for histopathologic examination is essential to confirm IgG4-related disease. Physicians must maintain a high level of suspicion for the disease for proper management.

IgG4-related hypophysitis: A monocentric experience from North India

Background

Immunoglobulin (Ig)G4-related disease is a systemic fibroinflammatory disease characterized by dense infiltration of IgG4-positive plasma cells in the affected tissue(s) with or without elevated plasma levels of IgG4. Hypophysitis itself is a very rare disease with reported prevalence in the operative specimens are around 0.2-0.88%. IgG4-related hypophysitis (IgG4-RH) may account for a substantial percentage of cases previously regarded as idiopathic hypophysitis.

Methods

This study is a registry-based, retrospective, and cohort study from a tertiary care hospital in North India. The medical records and clinical data of biopsy-proven and suspected IgG4-RH patients registered were retrospectively analyzed. Treatment outcome of cases was also explored during this analysis.

Results

Two thousand and six sellar area space-occupying lesions have been operated-on since 2006, among them only four patients had IgG4-RH on histopathological specimen. One case was diagnosed on clinical suspicion. Mean age of the patients was 31.8 ± 6.32 years. Most frequent presenting complaint was headaches. Extracranial manifestations were present in four patients. The most common pituitary dysfunction was cortisol deficiency. 18 F-fluorodeoxyglucose positron emission tomography (18F FDG PET) was helpful in three cases for diagnosis of hypophysitis and other organ involvement. Classical histological findings with storiform fibrosis, obliterative phlebitis seen in two cases, and IgG4-positive plasma cell infiltration were positive in four cases. Surgery was the primary modality of treatment in all four cases. Only one patient received steroids as a primary therapeutic modality.

Conclusion

IgG4-RH is rare. High index of suspicion is required to diagnosis the case precisely. FDG PET is helpful in diagnosing hypophysitis and extrapituitary lesions.

Pulmonary IgG4-related disease with favourable response to rituximab: A case report

Pulmonary involvement of IgG4-associated disease is a rare condition with no codified treatment apart from steroid administration. We report here the case of a patient with pulmonary involvement of IgG4-RD successfully managed with Rituximab, in induction and maintenance therapy. This original case could support the use of Rituximab in rare situations of steroid-resistant or steroid-dependent pulmonary IgG4-RD.

The landscape of T and B lymphocytes interaction and synergistic effects of Th1 and Th2 type response in the involved tissue of IgG4-RD revealed by single cell transcriptome analysis

OBJECTIVES

To investigate the landscape of T-B cell interaction, immune receptor profiles and effects of different types of immune responses in the involved tissues of IgG4-RD.

METHODS

Single cell RNA sequencing, bulk sample RNA sequencing, immune receptor repertoire analysis (both BCR and TCR), multi-color flow cytometry, and in-vitro assays with model cells (e.g. EBV-immortalized B cells from IgG4-RD patient) and histologic methods were applied to investigate the immunopathological features of IgG4-RD from multiple aspects.

RESULTS

Ectopic germinal center formation was observed in IgG4-RD patients at advanced disease stage, and a large part of B cells in involved tissue were germinal center B cell-like. Germinal center reaction in IgG4-RD led to the irregularities of both TCR and BCR clones in the involved tissues, and limited clonal overlaps among different samples. Enhanced Th1- and Th2-type responses were observed in involved tissues of IgG4-RD and patients with both increased Th1- and Th2-type response related cell subsets possessed more severe inflammatory indices. Analyses to the origin of IGHG4 transcripts in IgG4-RD indicated that IgG4 could be switched from IgM directly, or from other IgG subclasses. In vitro assays with EBV-immortalized B cells, fibroblasts and epithelial cells revealed the effects of Th1-type and Th2-type responses on germinal center reaction, ectopic expression of MHC-II molecules, and formation of tertiary lymphoid structures.

CONCLUSIONS

Synergistic effects of Th1- and Th2-type responses were involved in the pathogenesis of IgG4-RD via their influences on both acute inflammatory processes and the chronicity and complexity of IgG4-RD.

Vascular/perivascular inflammation in IgG4-related disease

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is characterized by the infiltration of IgG4-positive plasma cells and fibrosclerotic inflammation in multiple organs. Although vascular complications are present in some patients with IgG4-RD, vascular and/or perivascular inflammatory activity compared to control subjects remains unknown. This study sought to investigate vascular/perivascular inflammation in IgG4-RD patients compared to control subjects using 18F-fluorodeoxyglucose-positron emission tomography combined with computed tomography (FDG-PET/CT).

METHODS

We examined 37 consecutive patients diagnosed as IgG4-RD (29 males, mean age of 64.3 ± 8.3 years old), who underwent FDG-PET/CT. Thirty-seven age- and gender-matched subjects without IgG4-RD were employed as controls. Vascular/perivascular inflammation was quantified by blood-normalized standardized uptake value, known as a target-to-background ratio (TBR).

RESULTS

All IgG4-RD patients presented with multiple region involvements. Twelve (32.4%) of the IgG4-RD patients had vascular complications, all of which appeared in the abdominal aorta. IgG4-RD patients had significantly higher TBR values in the descending aorta, abdominal aorta, and common iliac artery than control subjects. Also, IgG4-RD patients with vascular complication exhibited higher TBR values in the infra-renal aorta and common iliac artery than those without vascular complication.

CONCLUSIONS

We found that vascular FDG activity is significantly elevated in IgG4-RD patients regardless of vascular complication than control subjects. FDG-PET/CT is a useful modality for assessing vascular/perivascular inflammation, which may contribute vascular complication in IgG4-RD patients.

Comparison of Clinical Manifestations and Pathology between Kimura Disease and IgG4-Related Disease: A Report of Two Cases and Literature Review

Kimura disease (KD) is a rare, chronic proliferative condition presenting as a subcutaneous mass predominantly located in the head and neck region; it is characterized by eosinophilia and elevated serum IgE levels. IgG4-related disease (IgG4RD) is a fibroinflammatory condition characterized by swelling in single or multiple organs and the infiltration of IgG4 plasma cells. Herein, we presented two cases. Case 1 is a 38-year-old man with a painless mass in his right postauricular region, and Case 2 is a 36-year-old man with painless lymphadenopathy in his bilateral postauricular region. After surgical excision, they showed good recovery with no relapse. Although Cases 1 and 2 shared several overlapping pathological manifestations, there were a few differences that allowed the differentiation of KD and IgG4RD.

Multimodality Imaging Evaluation of Coronary IgG4-Related Disease: A "Tumor-Like" Cardiac Lesion

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibro-inflammatory disorder. Coronary IgG4-RD has been scarcely reported and may present as "tumor-like" lesions. These pseudo-masses may be underdiagnosed mainly due to a vague clinical picture that can vary from complete lack of symptoms to acute coronary syndrome or sudden cardiac death. Early recognition of coronary IgG4-RD is essential to monitor disease activity and prevent life-threatening complications. We report a comprehensive non-invasive imaging evaluation of a patient affected by coronary IgG4-RD, which was diagnosed as an incidental finding during routine pre-laparoscopic cholecystectomy checkup. Non-invasive imaging revealed the presence of a peri-coronary soft-tissue mass that was stable at 12 months follow-up.

Curative Pericardiectomy in Interpheron-Resistant Severe Pericardial Erdheim-Chester Disease

Erdheim-Chester disease is a rare clonal non-Langerhans cell histiocytosis with multisystemic involvement. It affects bones, large vessels, and retroperitoneum. Cardiac involvement is one of the main mortality predictors.¹ We present an unusual case that debuted with cardiac tamponade and pericardial constriction requiring pericardiectomy for definitive control. (Level of Difficulty: Intermediate.).

A rare case report of primary Sjögren’s syndrome with clinical characteristics similar to those of CLIPPERS

Background

Primary Sjögren’s syndrome (pSS) is an autoimmune inflammatory disease characterized by dryness of the eyes, mouth and other mucous membranes. Patients with pSS can also present with extraglandular manifestations, such as pulmonary, kidney and nervous system involvement. Central nervous system (CNS) manifestations have rarely been described in pSS.

Case presentation

A 33-year-old man was admitted with a one-month history of dizziness, speech disturbance, and walking instability. His brain enhanced magnetic resonance imaging (MRI) showed symmetrical, enhanced “salt-and-pepper-like” speckled lesions in the brainstem, basal ganglia, and subcortical regions, and his diagnosis was considered possible chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS). Further examination revealed that anti-SSA antibody was positive, and the Schirmer test and labial salivary gland histopathology were abnormal, which supported the diagnosis of pSS.

Conclusion

pSS is a chronic systemic autoimmune disease that involves neurological complications. This case suggests that CNS lesions of pSS can present with clinical and MRI findings similar to those of CLIPPERS.

Pulmonary and coronary arterial abnormalities in patients with IgG4-related disease

IgG4-related disease (IgG4-RD) is an immune-mediated multiorgan fibroinflammatory disorder with variable clinical presentations. IgG4-RD cardiovascular involvement is considered rare, with pulmonary arterial involvement reported in a small subset of cases. Known pulmonary artery manifestations include pulmonary arteritis, pulmonary artery stenoses and central pulmonary artery aneurysms. Here we report 2 different patients with multifocal dilatation of the segmental and subsegmental pulmonary arteries with differing degrees of severity. Both patients also had coronary arterial abnormalities.

Case report: IgG4-related intracranial lesions mimicking multiple sclerosis in a 14-year-old girl

Objectives

IgG4-related disease (IgG4-RD) is distinguished by the infiltration of IgG4-positive plasma cells in a variety of tissues and organs. Even so, central nervous system lesions associated with IgG4-RD are scarce. We present a case of IgG4-related brain parenchymal lesions that mimics multiple sclerosis in a young girl.

Methods

The patient was followed by our neurology and rheumatology teams. Clinical information was recorded, and the brain was screened using magnetic resonance imaging (MRI). During follow-up, we examined serum IgE, IgG and IgG4 and lymph node biopsy.

Results

Here, we presented details of a 14-year-old Chinese girl suffering from diplopia, left eyelid ptosis, right facial numbness, and right lower limb weakness admitted to our institute. Brain MRI revealed multiple sclerosis-like lesions in the brain parenchyma and spinal cord. During the follow-up, she developed lymphadenopathy. Elevation of serum, IgG, IgG4 and IgE and lymph node biopsy favors a diagnosis of IgG4-RD. The patient had a good response to glucocorticoids and mycophenolate mofetil. The literature review summarized eight previously reported IgG4-RD involving brain parenchyma.

Discussion

Our case expands the known age spectrum of IgG4-RD. The intracranial IgG4-RD is rare and could mimic multiple sclerosis. Careful examination and dynamic review of disease history are crucial in the differential diagnosis.

Report of Two Cases of Pediatric IgG4-Related Lymphadenopathy (IgG4-LAD): IgG4-Related Disease (IgG4-RD) or a Distinct Clinical Pathological Entity?

IgG4-related disease (IgG4-RD) is a recently discovered immune-mediated fibroinflammatory condition, uncommon in the pediatric population, that could involve multiple organs and induce cancer-like lesions and organ damage. Its main features are multiple injuries in different sites, a dense lymphoplasmacytic infiltrate rich in IgG4 plasma cells, storiform fibrosis, and often high serological concentrations of IgG4. Autoimmune pancreatitis is the most common manifestation, mainly in adults. Two cases of IgG4-RD in children with lymph node localization of disease are reported. Localized or systemic lymph node involvement is common, but lymph node enlargement as the first and only manifestation of IgG4-RD is unusual, and therefore, hard to differentiate from other diseases. IgG4-related lymphadenopathy (IgG4-LAD) is most likely a distinct disease, described as isolated lymphadenopathy, related to the presence of elevated numbers of IgG4-positive plasma cells. Both disorders are likely to be misdiagnosed in children because they are characterized by rare and polymorphic features. IgG4-RD and IgG4-LAD should be considered in the differential diagnosis of disorders characterized by lymphadenopathy of uncertain etiology.

Autoimmune Pancreatitis and Immunoglobulin G4-related Sclerosing Cholangitis: Past, Present, and Future

The emergence of glucocorticoid-responsive autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC), a new disease entity, has attracted considerable interest within the international gastroenterology community. The typical manifestations of AIP/IgG4-SC are obstructive jaundice and pancreatic enlargement in the elderly, which may mimic the presentations of pancreatobiliary malignancies. The timely diagnosis of AIP/IgG4-SC can lead to adequate glucocorticoid treatment, whereas a misdiagnosis can result in unnecessary major surgery. The diagnostic criteria used to diagnose AIP include several cardinal features of AIP that can be detected via pancreatic parenchymal imaging, ductal imaging, serum IgG4 levels, histopathology, other organ involvement, and response to glucocorticoid therapy. The differential diagnosis of AIP/IgG4-SC may include pancreatobiliary malignancies and primary sclerosing cholangitis. Although most patients with AIP/IgG4-SC respond well to glucocorticoid therapy, there is a frequent relapse of the disease in the long term. This review describes the evolution of the concept of AIP and IgG4-related disease, including the development of diagnostic criteria, discusses the current practice for diagnosis and treatment, and suggests prospects for research.

Idiopathic Multicentric Castleman Disease with Strikingly Elevated IgG4 Concentration in the Serum and Abundant IgG4-Positive Cells in the Tissue: A Case Report

Idiopathic multicentric Castleman disease (iMCD) can be challenging to distinguish clinically and histopathologically from Immunoglobulin G4-related disease (IgG4RD). A 73-year-old man was referred to a rheumatologist for suspected autoimmune-related polyclonal hypergammaglobulinemia. The patient had a history of multiple lymphadenopathies in the neck for over 20 years. Laboratory data showed elevated serum immunoglobulin G4 (IgG4) levels, hypergammaglobulinemia, high C-reactive protein (CRP) levels, marked anemia, and positivity for several autoantibodies. Additionally, imaging studies revealed multiple enlarged lymph nodes and multifocal, ill-defined, small patchy opacities over the lung. Biopsies of the neck lymph node and right lung revealed typical features of multicentric Castleman disease (MCD). Immunohistochemical staining was negative for human herpesvirus-8 (HHV-8) in both lymph nodes and the right lung, sub-classified as iMCD, whereas the IgG4/IgG ratio was >40%, which raised the suspicion of IgG4RD. However, serological cytokine analysis demonstrated an increased interleukin-6 (IL-6) level, alongside systemic inflammatory and histopathological features, distinguishing MCD from IgG4RD in this patient. The patient was treated with short-term glucocorticoids and regular infusion of an anti-IL-6 receptor monoclonal antibody (tocilizumab), with satisfactory clinical and radiographic responses. Notably, differentiating MCD from IgG4RD is crucial for optimal treatment. Clinical and pathological features may assist in distinguishing between these two diseases.

Laboratory characteristics of IgG4-related disease: A retrospective study from a single tertiary medical center

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition with unique histopathological features that can affect most organs, making diagnosis challenging. This study characterized detailed laboratory characteristics of IgG4-RD. Baseline clinical and laboratory features of 33 patients with IgG4-RD were reviewed, including serum IgG4 concentrations, serum free light chains (sFLCs), IgGĸ- and IgGλ-heavy/light chains (HLCs), capillary serum protein electrophoresis (SPE), and immunofixation electrophoresis (IFE) of IgG4 subclass. The cohort of 33 patients showed male predominance (94%), with 8 (24%) exhibiting multiple organ involvement. Most patients (88%) had an elevated IgG4 concentration, and 67% had elevated erythrocyte sedimentation rate and IgE levels. Median IgG4 concentration at baseline was significantly higher in patients with >2 organs involved than those with ≤2. Furthermore, erythrocyte sedimentation rate was significantly correlated with serum IgG4 concentrations at baseline. SPE results demonstrated polyclonal gammopathy in most patients. Half of the patients had an increased κ/λ sFLC ratio, 42% had an increased IgGκ/IgGλ HLC ratio. Most patients exhibited hypergammaglobulinemia in the anodal end of the ɤ region on SPE. This study describes detailed laboratory features of IgG4-RD. Although none of these tests are considered diagnostically sufficient by itself, the provided laboratory characteristics can increase awareness of this disorder and help distinguish it from other IgG4-RD mimics.

Granulomatosis with Polyangiitis Overlapping with IgG4-Related Disease

IgG4-related disease and granulomatosis with polyangiitis share several features as well as the presence of ANCA antibodies and serum IgG4 immunoglobulins. It is often difficult to distinguish between two entities. We hereby report the case of a patient portraying the clinical conundrum with clinical and biological features of the two diseases.

IgG4-related disease associated with the primary manifestation of recurrent cerebral venous thrombosis: A rare case report

Nervous system involvement in IgG4-related systemic disease (IgG4-RD) is rarely reported and manifests as hypertrophic pachymeningitis and hypophysitis. In this report, a 33-year-old woman with neurological manifestations was diagnosed with IgG4-RD by biopsy. The patient showed improvement in symptoms after treatment.

IgG4-Related Sclerosing Disease of the Temporal Bone: A Systematic Review

OBJECTIVE

IgG4-related disease (IgG4-RD) involving the temporal bone is an uncommon and underrecognized pathology often mistaken for malignancy. This systematic review is the first that aims to thoroughly analyze IgG4-RD of the temporal bone.

DATABASES REVIEWED

Ovid MEDLINE, EMBASE, Cochrane Library, and Google Scholar.

METHODS

We used the following search keywords: "lgG4-RD," "skull," "skull base," "cranial," "temporal bone," "inner ear." We additionally manually searched the bibliographies of relevant articles. The JBI Critical Appraisal Checklist for Case Reports and Case Series was used to assess the risk of bias; because of the scarcity of the reports, data were available through limited case series and reports; thus, data synthesis was not possible.

RESULTS

We identified 17 studies with 22 cases with temporal bone involvement. The most common presenting symptoms were hearing loss, otalgia, and headache. The mastoid and petrous bone were the most affected anatomical areas. Both computed tomography and magnetic resonance imaging were used. Biopsies showed the characteristic lymphoplasmacytic infiltrate in all cases, with histopathology being the diagnostic modality that set the diagnosis. Most patients were treated with corticosteroids ± surgery or a combination of corticosteroids and immunosuppressants with 95.5% symptomatic response and disease control.

CONCLUSION

IgG4-RD of the temporal bone radiologically manifests as space-occupying, lytic lesions; clinically, it presents with vague otological symptoms. Diagnosis involves a thorough workup, with histopathology being crucial in setting a definite diagnosis. IgG4-RD tends to respond well to systemic corticosteroids, whereas surgery is mostly required for diagnostic purposes.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis With Immunoglobulin G4 Involvement in Lacrimal Sac Squamous Cell Carcinoma

Lacrimal sac squamous cell carcinoma is a rare but life-threatening disease that is often a delayed diagnosis secondary to difficulty in differentiating from other causes of dacrocystitis and acquired nasolacrimal duct obstruction. Chronic inflammation, including that of an underlying autoimmune disease, prior instrumentation, and poor wound healing, may be risk factors in the development to lacrimal sac squamous cell carcinoma. The authors present the first case of lacrimal sac squamous cell carcinoma associated with antineutrophil cytoplasmic antibody-associated vasculitis and immunoglobulin G4 positivity. Rather than an overlap syndrome between antineutrophil cytoplasmic antibody-associated vasculitis and immunoglobulin G4-related disease, high immunoglobulin G4 positivity may be considered an inflammatory marker of disease severity in the setting of antineutrophil cytoplasmic antibody-associated vasculitis and underlying malignancy. Inflammation-mediated tumorangiogenesis should be considered in the development of malignancy and red flags of chronic uncontrolled inflammation should warrant a lower threshold for further workup.

Tubarial gland involvement in IgG4-related diseases

BACKGROUND

Tubarial glands (TGs) are a collection of unidentified salivary glands overlying the torus tubarius in the nasopharyngeal wall. Immunoglobulin G4-related disease (IgG4-RD) is a chronic fibroinflammatory state that often has multiple organ involvement. Involvement of the head and neck, especially the salivary glands, is common in IgG4-RD.

AIMS/OBJECTIVES

This study aimed to elucidate the clinical significance of TGs in IgG4-RD.

MATERIALS AND METHODS

We investigated the local findings of TGs in ten patients with IgG4-RD.

RESULTS

Nasopharyngeal endoscopic examination revealed oedematous swelling of the nasopharyngeal wall surrounding the TGs, which improved after steroid treatment. Moreover, sonotubometry showed a stenotic pattern in three out of seven patients with IgG4-RD.

CONCLUSIONS AND SIGNIFICANCE

TGs may be involved in IgG4-RD. The swollen TGs may be responsible for obstructive Eustachian tube dysfunction. Further studies are required to clarify the clinical significance and physiological roles of TGs in IgG4-RD.

The glucocorticoid toxicity index: Measuring change in glucocorticoid toxicity over time

Glucocorticoids (GCs) have been the cornerstone of treating dozens of inflammatory conditions for more than seven decades. GC toxicity is ubiquitous in both clinical trials and clinical practice, and toxicities associated with GC use are central to the experience of most patients being treated for immune-mediated conditions. These conditions span the full range of medical specialties, including rheumatology, nephrology, gastroenterology, neurology, pulmonology, ophthalmology, and others. One of the goals of novel therapies for inflammatory disease must be to diminish the effects of GC toxicity in clinically important ways, thereby differentiating these new treatments from existing approaches. Despite the importance of glucocorticoids in the treatment of inflammatory disease for more than 70 years, no reliable means of calculating the degree to which GC toxicity has worsened or improved over the course of treatment has been available. The Glucocorticoid Toxicity Index (GTI), developed by an international group of subspecialty physician experts as a clinician-facing clinical trials outcome measure, is a standardized, validated measure of the phenomenon known as GC toxicity. The purpose of the instrument is to measure change in GC toxicity between two points in time: for example, between the baseline visit and the time of the primary efficacy outcome assessment. The instrument is designed to quantify both worsening and improvement in GC toxicity. The GTI has been validated in both real-world experiences and clinical trials, including a phase 3, label-enabling trial in ANCA associated vasculitis. This article reviews the history and rationale for the development of the GTI, describes key data from validation studies, considers the minimum clinically important difference, and provides instructions for use of the instrument.

IgG4-Related Disease: A Rare Case of Simultaneous Lung and Retroperitoneal Involvement

Immunoglobin G4-related disease is a progressive immune-mediated fibroinflammatory condition that can affect any organ, causing a tumor-like swelling appearance. We present a case of a 57-year-old male who presented with a one-month history of weight loss, constant abdominal pain with dorsal irradiation, night sweats, and respiratory symptoms. CT scan revealed multiple mediastinal and retroperitoneal adenopathies, right pulmonary consolidation, and retroperitoneal fibrosis. Transthoracic pulmonary biopsy and excisional cervical lymph node biopsy revealed fibroinflammatory disease related to IgG4, with normal serum IgG4. The patient presented a good response to glucocorticoids, a clinical characteristic of this disease. The diagnosis of immunoglobin G4-related disease is challenging, due to the nonspecific clinical manifestations, requiring a high level of suspicion in order to perform the appropriate immunohistochemical examination.

Magnetic Resonance Imaging of Head and Neck Emergencies, a Symptom-Based Review, Part 1: General Considerations, Vision Loss, and Eye Pain

Use of magnetic resonance (MR) imaging in the emergency department continues to increase. Although computed tomography is the first-line imaging modality for most head and neck emergencies, MR is superior in some situations and imparts no ionizing radiation. This article provides a symptom-based approach to nontraumatic head and neck pathologic conditions most relevant to emergency head and neck MR imaging, emphasizing relevant anatomy, "do not miss" findings affecting clinical management, and features that may aid differentiation from potential mimics. Essential MR sequences and strategies for obtaining high-quality images when faced with patient motion and other technical challenges are also discussed.

The disturbance of the distribution of T helper cell subsets in the mantle area surrounding germinal centers in immunoglobulin G4-related sclerosing sialadenitis

The function of germinal centers (GCs) is an important factor in the pathogenesis of immunoglobulin G4 (IgG4)-related disease, in which inflammatory and fibrotic processes are controlled by type 2 helper T (Th) cells and regulatory T cells. T follicular helper cells (Tfh), which are present in GCs, regulate GC development, and they consist of Tfh1, Tfh2, and Tfh17 subsets. This study examined the association of Th cell subsets in IgG4-RD and pathogenesis of the disease using whole-slide image analysis for immunohistochemistry. IgG4-related sclerosing sialadenitis (IgG4-SS, n = 19) was characterized by higher numbers of Tfh2 and Tfh17 cells than Tfh1 cells compared to the findings in patients with chronic sialadenitis (n = 18) or Sjögren syndrome (n = 17). The number of Tfh2 cells was significantly associated with all parameters of GC structures and the number of IgG4 + plasmacytes, whereas the number of Tfh1 cells was inversely associated with the aforementioned parameters. Concerning extrafollicular helper T (Teh) cells, among three groups, the Tfh2/Teh2 ratio was highest and the Tfh1/Teh1 ratio was lowest in the IgG4-SS group, which exhibited a characteristically regional distribution of Tfh and Teh subsets, especially higher numbers of Teh2 cells and lower numbers of Teh1 cells in the mantle areas surrounding GCs. Mantle Teh2 cells and central Tfh17 cells were significantly correlated with morphological abnormalities of GCs. Our results indicated that the peculiar regional distribution and altered balance of Tfh and Teh subsets are novel hallmarks of IgG4-SS that are associated with GC formation in IgG4-SS.

Respiratory lesions in IgG4-related disease: Classification using 2019 ACR/EULAR criteria

In 2019, the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) proposed classification criteria for IgG4-related disease (IgG4-RD) [1,2]. IgG4-RD can cause fibroinflammatory lesions characterised by infiltration of abundant IgG4-positive plasma cells with fibrosis and an elevated serum IgG4 concentration [3–5]. Approximately 35% of patients with IgG4-RD present with intrathoracic lesions, including those involving the mediastinal lymph nodes, bronchial walls and peribronchovascular bundles [6–8]. To increase diagnostic sensitivity and specificity, we previously proposed diagnostic criteria for IgG4-related respiratory disease (IgG4-RRD) [9].

In this study, ILDs involving IgG4-positive plasma cell infiltration were classified using the 2019 ACR/EULAR criteria. Most IgG4-positive interstitial pneumonia cases were excluded, suggesting the need for a unique treatment strategy.https://bit.ly/38GiUJM

Supraglottic Localization of IgG4-Related Disease—Rare and Challenging Equity

Supraglottic stenosis is a rare symptom, particularly in fibroinflammatory multifocal diseases, such as IgG4-related disease (IgG4-RD). There is still an inconsistency in the diagnosis of less-common locations of IgG4-RD, which causes a delay in the diagnosis and treatment. Our paper aims to analyze different aspects of IgG4-RD presenting as supraglottic stenosis, including the possible overlap with ANCA-associated vasculitis. We compare the usefulness of the recently revised ACR/EULAR and Comprehensive criteria and discuss treatment options. The review was performed according to PRISMA guidelines using the MEDLINE Pubmed and Scopus databases. The analysis includes nine papers describing supraglottic laryngeal stenosis in 13 patients. Furthermore, we present a case of a woman with ongoing supraglottic stenosis presenting with cough, temporary dyspnea and stridor as the symptoms of localized IgG4-RD. At the time of writing, the patient remains in remission while receiving treatment with cyclophosphamide and methylprednisolone. The symptoms of supraglottic localization of IgG4-RD may be severe; however, at that point, clinicians should suspect autoimmune etiology and attempt to modulate the autoimmune response instead of performing dilatation surgery—the effects of which may not result in extended intervals between interventions. The ACR/EULAR criteria show great specificity; however, when IgG4-RD is presumed, the specific treatment should be implemented.

The levels of IL-1β and soluble IL-1 receptors in patients with IgG4-related periaortitis/periarteritis

PURPOSE

IgG4-related disease (IgG4-RD) is a chronic fibrotic inflammatory and an immune-mediated disease characterized by high serum IgG4 concentration and IgG4-bearing plasma cell infiltration in affected organs. IgG4-related periaortitis/periarteritis is a recently identified disease entity in IgG4-RD that affects the cardiovascular system, and its pathogenesis and characteristics remain unclear. The inflammatory cytokine IL-1β is involved in a variety of cellular activities including inflammation, fibrosis, and angiogenesis. The present study compared the levels of the inflammatory cytokine IL-1β and two soluble IL-1 receptors, IL-1R1 and IL-1R2, between IgG4-RD patients with and without IgG4-related periaortitis/periarteritis.

METHODS

The patients with IgG4-related periaortitis/periarteritis (n ​= ​38), those without (n ​= ​66) and healthy (n ​= ​33) were recruited to measure cytokines of IL-1β and soluble receptors (sIL-1R1 and sIL-1R2) in sera by ELISA assay.

RESULTS

Serum IgG4 was significantly higher in patients with periaortitis/periarteritis compared to non-periaortitis/periarteritis (p ​= ​0.0074), while serum IL-1β was significantly lower in patients with periaortitis/periarteritis (p ​= ​0.00037). The three groups did not show significant difference in sIL1-R1, while sIL-1R2 in the periaortitis/periarteritis and healthy group was higher than in the group without periaortitis/periarteritis (p ​= ​0.00001).

CONCLUSIONS

The characteristic changes in IL-1β, sIL-1R1, and sIL-1R2 levels in IgG4-RD patients with and without IgG4-related periaortitis/periarteritis may indicate an active phase of the inflammatory process in these diseases.

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.

[Immunoglobulin-G4-related disease]

After years of confusion about apparently distinct clinical disease symptoms, the term IgG4-related disease (IgG4-RD) has been coined in 2001, uniting these fibroinflammatory clinical entities with a tendency for tumorous enlargement and tissue fibrosis. Over the past two decades, experimental and clinical studies could make astounding progress in the understanding of this elusive disease. By now, we have a reasonable idea of the pathophysiological mechanisms, which opens up new avenues for therapeutic approaches. It seems like a dense lymphoplasmacytic cell infiltrate, consisting of B‑cells, IgG4⁺ plasma cells, follicular T‑helper cells, CD4⁺ cytotoxic T‑cells and M2 macrophages induces a smoldering inflammatory reaction with a fibrogenic cytokine milieu. This stimulates fibroblasts to secrete extracellular matrix components, leading to the histopathologically characteristic storiform fibrosis and obliterative phlebitis. Macroscopically, this reaction results in diffuse organ swelling and tumorous lesions. The macroscopic and histological differentiation from conditions mimicking IgG4-RD can be challenging. This is especially true for granulomatous diseases, such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The situation is further complicated by the fact that ANCAs can be positive in IgG4-RD and, vice versa IgG4 antibodies can be elevated in numerous differential diagnoses, such as infections, AAV, sarcoidosis, and malignancies. This article provides an overview of the multifaceted clinical condition of IgG4-RD with respect to the pathophysiology, diagnostic steps and treatment. Furthermore, an overview of the differential diagnoses is discussed especially with respect to granulomatous diseases.

A Case of Hepatic Immunoglobulin G4-Related Disease Presenting as an Inflammatory Pseudotumor and Sclerosing Cholangitis

An inflammatory pseudotumor is a benign disease characterized by tumor-like lesions consisting of inflammatory cells including plasma cells and fibrous tissue. Recently, some inflammatory pseudotumor cases proved to be a form of Immunoglobulin G4-related disease (IgG4-RD). This novel clinical entity, recognized as a fibroinflammatory condition, is characterized by lymphoplasmacytic infiltration with a predominance of IgG4-positive plasma cells, storiform fibrosis, and often elevated serum IgG4 concentrations. We report a case of IgG4-RD in the form of an inflammatory pseudotumor in the liver with combined sclerosing cholangitis. We recommend that for diagnosing IgG4-RD accurately, it is important to obtain adequate tissue samples and follow-up the lesion in clinical practice.

Prognostic implication of IgG4 and IgG1-positive cell infiltration in the lung in patients with idiopathic interstitial pneumonia

Immunoglobulin (Ig) G4-positive cells are rarely observed in the lungs of patients with idiopathic interstitial pneumonias (IIPs). IgG1 may be more pathogenic than IgG4, with IgG4 having both pathogenic and protective roles in IgG4-related disease (IgG4-RD). However, the role of both IgG1 and IgG4 in IIPs remains unclear. We hypothesized that patients with IgG4-positive interstitial pneumonia manifest different clinical characteristics than patients with IgG4-RD. Herein, we identified the correlation of the degree of infiltration of IgG1- and IgG4-positive cells with IIP prognosis, using a Japanese nationwide cloud-based database. We included eighty-eight patients diagnosed with IIPs after multidisciplinary discussion, from April 2009 to March 2014. IgG4-positive cell infiltration was identified in 12/88 patients with IIPs and 8/41 patients with idiopathic pulmonary fibrosis (IPF). Additionally, 31/88 patients with IIPs and 19/41 patients with IPF were diagnosed as having IgG1-positive cell infiltration. IgG4-positive IIPs tended to have a better prognosis. Conversely, overall survival in cases with IgG1-positive IPF was significantly worse. IIPs were prevalent with IgG1- or IgG4-positive cell infiltration. IgG1-positive cell infiltration in IPF significantly correlated with a worse prognosis. Overall, evaluating the degree of IgG1-positive cell infiltration may be prognostically useful in cases of IPF.

Clinical and pathological predictors of relapse in IgG4-related disease

OBJECTIVES

In IgG4-related disease, the relationship between pathological findings and relapse has not been well established. This study aimed to identify the clinical and pathological predictors of disease relapse in IgG4-RD.

METHODS

Patients with newly diagnosed IgG4-RD (n = 71) were enrolled between January 2011 and April 2020; all cases were pathologically confirmed. The clinical and pathological features were recorded in a database at baseline and each follow-up visit. Patients were followed up at least once a month via outpatient clinic examinations and telephone calls. Univariate and multivariate Cox regression analyses and receiver operating curve (ROC) analysis were used to identify the predictors of disease relapse and to assess their predictive value.

RESULTS

Over a median follow-up of 26 (range, 6-123) months, 3/71 (4.2%) patients died. Of the remaining 68 patients, 47 (69.1%) patients had achieved clinical remission and 21 (30.9%) had suffered relapse at the last follow-up. The independent predictors of relapse were IgG4 ≥ 6.5 g/L (HR = 2.84, 95% CI: 1.11-7.23), IgG ≥ 20.8 g/L (HR = 4.11, 95% CI: 1.53-11.06), IgG4-RD responder index (RI) ≥ 9 (HR = 3.82, 95% CI: 1.28-11.37), and severe IgG4+ plasma cell infiltration (HR = 6.32, 95% CI: 1.79-22.41). A prognostic score developed using three of the identified predictors (IgG ≥ 20.8 g/L, IgG4-RD RI ≥ 9, and severe IgG4+ plasma cell infiltration) showed good value for predicting impending relapse (AUC, 0.806).

CONCLUSIONS

In patients with IgG4-RD, IgG4 ≥ 6.5 g/L, IgG ≥ 20.8 g/L, IgG4-RD responder index (RI) ≥ 9, and severe IgG4+ plasma cell infiltration are predictors of relapse.

IgG4-related hypophysitis: a retrospective cohort study

Purpose

IgG4-related hypophysitis (IgG4-RH) is a rare chronic inflammatory condition of the pituitary gland. This study reports the presentation, management and outcomes for patients with histologically proven IgG4-related hypophysitis.

Methods

A prospectively maintained electronic database was searched over a 14-year period from 1 January 2007 to 31 December 2020 at a single academic centre to identify all patients with a histological diagnosis of IgG4-RH. A retrospective case note review from electronic health records was conducted for each case to extract data on their presentation, management and outcomes.

Results

A total of 8 patients (5 male) with a median age of 51 years were identified. The most common presenting symptoms were headache (4/8; 50%), fatigue (3/8; 37.5%) and visual impairment (2/8; 25%). Three patients were initially treated with high-dose steroids aiming for reduction of the pituitary mass. However, ultimately all patients underwent transsphenoidal surgery. Post-operative changes included radiological reduction in pituitary mass in all patients that had imaging (7/7; 100%), improvement in vision (1/2; 50%), residual thick pituitary stalk (5/7; 71.4%), persistent anterior hypopituitarism (4/8; 50%) and panhypopopituitarism including diabetes insipidus (3/8; 37.5%).

Conclusions

IgG4-RH is an increasingly recognised entity presenting with a variety of symptoms and signs. Clinical presentation is similar to other forms of hypophysitis. It is therefore important to consider IgG4-RH as a differential and to have a low threshold for pituitary biopsy, the diagnostic gold standard. The diagnosis of IgG4-RH will guide decisions for additional workup for IgG4-related disease, multi-disciplinary team involvement and follow-up.

Isolated esophageal IgG4-related disease presenting with progressive dysphagia and weight loss in a middle-aged man

Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognized immune-mediated condition that results in inflammation, stricturing and mass formation. It causes a wide spectrum of disease and clinical presentations depending on the organ system involved. Isolated esophageal IgG4-RD is rare and diagnosis can be difficult. It is highly responsive to corticosteroids, and early identification and instigation of management is key.We describe the case of a 47-year-old man who presented with a food bolus obstruction on a background of progressive dysphagia and weight loss. Imaging and gastroscopy demonstrated diffuse esophageal thickening with a benign appearing stricture. Following non-specific histologic findings on biopsy and a non-diagnostic endoscopic ultrasound guided fine needle aspiration, he underwent video-assisted thoracoscopic surgery with esophageal core biopsy. This confirmed the diagnosis of IgG4-RD. Initial treatment was with corticosteroids. However, due to recurrence of symptoms upon weaning of corticosteroids, azathioprine maintenance therapy was instituted. Azathioprine has previously been used in systemic cases of IgG4-RD but has not been reported for isolated esophageal disease.This case highlights the difficulties in the diagnosis and treatment of esophageal IgG4-RD and the need to consider it as a differential diagnosis when histology reveals esophagitis with lymphoplasmacytic infiltration.

Derivation and Validation of Algorithms to Identify Patients With Immunoglobulin-G4-Related Disease Using Administrative Claims Data

OBJECTIVE

Immunoglobulin-G4-related disease (IgG4-RD) is a systemic autoimmune disease that can affect nearly any organ, but its epidemiology remains poorly understood. Validated algorithms to identify cases in claims data will enable studies to describe IgG4-RD epidemiology in the general population.

METHODS

Potential claims-based algorithms were developed by IgG4-RD experts using a combination of International Classification of Diseases, Ninth Revision (ICD-9) and International Classification of Diseases, 10th Revision (ICD-10) codes, dispensed medications, and procedure codes for immunoglobulin G (IgG) subclass testing. Algorithms were tested using Medicare Parts A, B, and D linked to medical records (2007-2017). Classification of cases as IgG4-RD was determined using the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) classification criteria for IgG4-RD. We estimated the positive predictive value (PPV) of each algorithm; sensitivity was determined using a cohort of patients with IgG4-RD also enrolled in Medicare Parts A, B, and D during the study period.

RESULTS

We identified seven algorithms that used a combination of ICD-9 and ICD-10 codes, medication prescriptions, and/or IgG subclass tests to identify patients with IgG4-RD. The PPV of algorithms in the derivation cohort ranged from 57% to 100%, and sensitivity ranged from 0% to 58%. The best performing algorithm in the validation cohort had a PPV of 81% and a sensitivity of 58%. Typical IgG4-RD manifestations were observed in the cohort (n = 36) assembled by this algorithm, including 50% with sialadenitis, 64% with pancreatic disease, 31% with renal disease, and 59% with an elevated IgG4 concentration.

CONCLUSION

We derived and validated a well-performing algorithm to identify IgG4-RD cases with typical manifestations of the disease. The claims-based algorithm can be used in research studies of IgG4-RD.

Eosinophilic granulomatosis with polyangiitis exhibits T cell activation and IgG4 immune response in the tissue; comparison with IgG4-related disease

Objective

To study the pathophysiological differences of EGPA and IgG₄-related disease (RD) by clarifying their clinical, pathological and immunological features.

Methods

Clinical and pathological findings were compared in patients with EGPA and IgG₄-RD. Peripheral blood mononuclear cells were used for comprehensive flow cytometric analysis.

Results

An elevation of the IgG4 level was found in all EGPA cases, with the accompanying pathological findings of lymphocytic infiltration and fibrosis observed in 30.8% patients, and the elevation of IgG₄/IgG ratio in 61.5% patients. However, actual IgG₄ levels, as well as the degree of the infiltration of IgG₄-positive plasma cells, were still higher in patients with IgG₄-RD than patients with EGPA. Examination by ACR/EULAR classification criteria showed only 13.6% of the EGPA patients met entry criteria, while all of them met the exclusion criteria. In regard to the immunophenotyping, EGPA patients had increases in activated CD4 and CD8 T cells compared with the healthy controls. However, no such similar changes occurred in IgG₄-RD patients. On the other hand, both the EGPA and IgG₄-RD patient groups had correlated increased plasmablasts and Tfh. These results indicate the presence of two axes: namely, the activation of T cells and that of B cells. Both axes are present in EGPA, but the T cell activation axis was not observed in IgG₄-RD.

Conclusions

The elevation of serum IgG₄ as well as pathological IgG₄ infiltration are not specific. Meanwhile, EGPA and IgG4-RD differ in immunological phenotypes, indicating the possible importance of the predominant activation of T cells in the development of vasculitis.

Case Report: Dual-Energy Computed Tomography of Cardiac Changes in IgG4-Related Disease

Background

Dual-energy computed tomography (DECT) is used in coronary plaque characterization, myocardial perfusion imaging, and pulmonary embolism diagnosis; however, there is no relevant research on DECT in IgG4-related diseases (IgG4-RD) involving the coronary artery. We are the first to report DECT findings of cardiac morphology and function in IgG4-RD.

Patient Findings

Multimodality cardiovascular imaging from a 63-year-old male patient, who presented with IgG4-related pancreatitis, was analyzed. An iodine map and spectral curves were obtained from the DECT, which can help to distinguish between non-calcified plaques and IgG4 lesions of the coronary artery, noninvasive FFR_CT (fractional flow reserve derived from coronary computed tomography angiography) and ECV (extracellular volume fraction) demonstrated myocardial ischemia and myocardial fibrosis, respectively.

Conclusion

The DECT can detect coronary artery tumor-like lesions caused by IgG4-RD and simultaneously assess the morphological, functional, and histological characteristics of the myocardium. This may help to guide individualized and timely treatment and avoid potentially life-threatening complications.

A Case of M-Type Phospholipase A2 Receptor-Associated Membranous Nephropathy With IgG4-Positive Cells Infiltration in the Interstitium

A 70-year-old man was referred to our department for evaluation of nephrotic syndrome. Renal biopsy revealed membranous nephropathy (MN). Immunohistochemical analysis demonstrated IgG4-positive staining in the glomeruli and interstitial cells. The presence of serum anti-phospholipase A2 receptor (PLA2R) antibody and enhanced staining of PLA2R in the glomeruli was noted. Computed tomography unidentified the extrarenal lesions of IgG4-related disease. He was diagnosed with PLA2R-associated MN possibly complicated with IgG4 related kidney disease (IgG4-RKD). Storiform fibrosis, a typical manifestation of IgG4-RKD, was not apparent. We herein describe a case of serologically and histologically confirmed PLA2R-associated MN with IgG4+ cell infiltration into the interstitium without any signs of IgG4-RD.

Orchestration of Immune Cells Contributes to Fibrosis in IgG4-Related Disease

This review summarizes recent progress in understanding the pathogenesis of IgG4-related disease (IgG4-RD), with a focus on fibrosis. Several studies reported that CD4+ T cells with cytotoxic activity promoted by the secretion of granzyme and perforin, cytotoxic CD4+ T cells (CD4+CTLs), and disease-specific activated B cells, infiltrated inflamed tissues and cooperated to induce tissue fibrosis in autoimmune fibrotic diseases such as IgG4-RD, systemic sclerosis, and fibrosing mediastinitis. An accumulation of cells undergoing apoptotic cell death induced by CD4+CTLs and CD8+CTLs followed by macrophage-mediated clearing and finally tissue remodeling driven by cytokines released by CD4+CTLs, activated B cells, and M2 macrophages may contribute to the activation of fibroblasts and collagen production. In IgG4-RD, this process likely involves the apoptosis of non-immune, non-endothelial cells of mesenchymal origin and subsequent tissue remodeling. In summary, CD4+CTLs infiltrate affected tissues where they may cooperate with activated B cells, CD8+CTLs, and M2 macrophages, to induce apoptosis by secreting cytotoxic cytokines. These immune cells also drive fibrosis by secreting pro-fibrotic molecules in IgG4-RD.

The Role of IgG4 in Autoimmunity and Rheumatic Diseases

The distinguishing of the IgG4-related disease (IgG4-RD) from among other rheumatic diseases has brought attention to the IgG4 subclass of immunoglobulins. It is the least numerous subclass among immunoglobulins G. In general, IgG4 is considered to be non-inflammatory and tolerance inducing, due to its unique structure. However, in IgG4-RD this antibody plays a pathogenic role in activation of the fibrinogenesis and of the inflammatory process; there are also suggestions that it may be a marker of an abnormal inflammatory response. The importance of IgG4 for the pathogenesis of allergic diseases, with a vital role of its ratio to immunoglobulin E (IgE/IgG4 ratio), has been known for years. The role of IgG4 in the course and pathogenesis of rheumatic diseases is still being researched and is not yet fully understood. Increased IgG4 levels have been revealed in rheumatoid arthritis, although no clear link between this phenomenon and disease activity has been demonstrated. There are articles on the potential importance of IgG4 concentration (of both elevated and decreased serum levels) in Sjogren’s syndrome. Additionally, anti-nuclear IgG4 antibody significant titers have been detected in SLE patients, and it has been suggested that the effect of these antibodies on complement consumption and the production of proinflammatory cytokines may play a role in inhibiting the progression of SLE. IgG4 plays a role in autoimmune diseases other than rheumatic diseases, such as pemphigus, bullous pemphigoid, idiopathic membranous glomerulonephritis, or myasthenia gravis, but also in helmints infections. Research shows the importance of IgG4 in malignancy of neoplasms. Melanoma cells are known to stimulate IgG4 production through a modified Th2-based inflammatory response. The role of this immunoglobulin in cholangiocarcinoma is also considered as possible. The aim of this review article is to discuss the current knowledge of IgG4 not only from the perspective of the IgG4-RD but also from a point of view of other autoimmune diseases with particular emphasis on rheumatic diseases.

Diffuse Large B-Cell Lymphoma 18 Years After Bilateral Lacrimal Gland IgG4-Related Disease: Case Report and Literature Review

IgG4-related disease is a recently established clinical entity. The disease might serve as the background for later development of systemic lymphoma. This study aims to confirm the diagnosis of IgG4-related disease by re-staining lacrimal gland lesions diagnosed previously with low-grade lymphoma in a patient who developed systemic diffuse large B-cell lymphoma (DLBCL) 18 years later. A 53-year-old man developed bilateral lacrimal gland swelling and right submandibular gland swelling and was diagnosed by excision as low-grade lymphoma. In follow-up, positron emission tomography showed high uptake in the median hyoid 11 years later but no malignancy was detected by laryngeal submucosal biopsy. He was well with no treatment until 18 years later when he had palatal swelling and was diagnosed with DLBCL by oral floor biopsy. He had systemic lymphadenopathy, infiltration in paranasal sinuses, hypopharynx, small intestine, kidney, and prostate. He underwent 8 courses of R-CHOP and 3 courses of high-dose methotrexate and achieved complete remission with no relapse for 1 year thereafter. Re-immunostaining of paraffin blocks of bilateral lacrimal gland lesions showed IgG and IgG4-positive lymphocytes and plasma cells among lymphoid follicles separated by fibrous bundles, with 10 or more IgG4-positive cells in high-power field. The IgG4/IgG-positive cell ratio was 100% and the number of κ chain-positive cells and λ chain-positive cells was the same. The bilateral lacrimal lesions were thus re-diagnosed as IgG4-related disease. In conclusion, systemic DLBCL occurred approximately 20 years after lacrimal gland IgG4-related disease. Literature review revealed 12 patients with IgG4-related disease, including the present patient, who later developed lymphoma in the other organs.

Immunoglobulin G4-related Disease: A New Systemic Disease Emerging in Japan

Immunoglobulin G4-related disease (IgG4-RD) is a fibro-inflammatory disease characterized by organ enlargement and elevated serum IgG4 levels. In 2003, IgG4-RD was proposed as a distinct form of IgG4-related systemic disease based on a histopathological study involving patients with autoimmune pancreatitis. IgG4-RD occurs mainly in older men and can affect almost any organ simultaneously or metachronously. Pathophysiologically, IgG4-RD occurs when an autoantigen triggers an immune response characterized by Th2 predominance with increased production of cytokines, such as interleukin 4 (IL-4), IL-5, IL-10, IL-13, and tumor growth factor-β (TGF-β), in the affected organ. IL-10 and TGF-β produced by the increased number of regulatory T cells induce a switch from B cells to IgG4-producing plasma cells and fibrosis, respectively. The characteristic histological features consist of dense infiltration of lymphocytes and IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. IgG4-RD is diagnosed based on a combination of clinical, serological, radiological, and histopathological findings. Differentiating IgG4-RD from malignant tumors or similar inflammatory diseases in the affected organs is important. The 2019 America College of Rheumatology/European League against Rheumatism classification criteria for IgG4-RD have high diagnostic sensitivity and specificity. IgG4-RD generally responds well to treatment with steroids, and a swift response is reassuring and provides further diagnostic confirmation. However, relapses are common during tapering or after cessation of steroids. In Japan, low-dose steroid maintenance therapy is usually given to prevent a relapse. B-cell depletion with rituximab is effective in patients resistant to or dependent on steroids. Most patients with IgG4-RD who receive steroid therapy show good short-term clinical, morphological, and functional outcomes. However, long-term outcomes, such as relapse, fibrosis development, and associated malignancies, have not been clearly defined. Therefore, novel treatment strategies, including rituximab, need to be tested in international randomized controlled clinical trials.

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.