International Consensus Guidance Statement on the Management and Treatment of IgG4-Related Disease

Overlap of IgG4-related Disease and Multicentric Castleman's Disease in a Patient with Skin Lesions

A 59-year-old man presented with multiple dark red erythemas with induration, anemia, and polyclonal hypergammaglobulinemia. A skin biopsy revealed the infiltration of lymphocytes and plasma cells and he was initially diagnosed with multicentric Castleman's disease (MCD). Glucocorticoid treatment was only partially effective. Four years later, the patient's bilateral lacrimal glands gradually became enlarged and a biopsy revealed dense lymphocyte and plasma cell infiltration with an IgG4+/IgG+ plasma cell ratio of 70%. The patient was diagnosed with IgG4-related disease (RD). Rituximab only had a slight effect. This case demonstrates that overlapping features of IgG4-RD and MCD may present in a single patient, which suggests a shared pathogenesis.

International consensus for the treatment of autoimmune pancreatitis

BACKGROUND AND AIMS

The International Consensus Diagnostic Criteria (ICDC) for AIP has proposed two distinctive type of AIP, type 1 and type 2, and enabled us first to differentiate two types of AIP each other. By initial steroid treatment for induction of remission, remission can be successfully induced in almost all subjects with type 1 and type 2 AIP. As relapse rate in type 1 AIP is significantly higher than in type 2 AIP, there has been ongoing debate on how to treat effectively relapse of type 1 AIP.

METHODS

By a modified Delphi approach, a panel of international experts has proposed an international consensus on the treatment of AIP after intense discussion and deliberation during an international consensus symposium of the International Association of Pancreatology (IAP) 2016.

RESULTS

Individual statements for nine clinical questions with recommendation levels and the therapeutic strategy have been proposed.

CONCLUSION

The recommendations are based on the available evidence, and eastern and western experts' opinions to find standard treatment of AIP worldwide. These recommendations can be tailored according to the local expertise and context in the management of individual patients.

Recent advances in knowledge regarding the head and neck manifestations of IgG4-related disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder, characterized by elevated serum IgG4 levels as well as abundant infiltration of IgG4-positive plasmacytes and fibrosis in various organs, including the head and neck region. In particular, the salivary glands, orbit, and thyroid are common sites of disease involvement. IgG4-RD is diagnosed based on various clinical, serological, and histopathological findings, none of which are pathognomonic. Hence, various differential diagnoses, which exhibit elevated serum IgG4 levels and infiltration of IgG4-postive cells into tissues, need to be excluded, especially malignant diseases and mimicking disorders. Systemic corticosteroids are generally effective in inducing IgG4-RD remission; however, recurrent or refractory cases are common. In addition, although the pathogenic mechanisms of IgG4-RD remain unclear, an antigen-driven inflammatory condition is believed to be involved. Recent studies have indicated the important pathogenic role of B cell/T cell collaboration and innate immunity in this disease. Nevertheless, additional research and discussions are needed to resolve many remaining questions. In this review, we provide an overview of the recent insights on the history, clinical features, diagnosis, and treatment of IgG4-RD in the head and neck region. Furthermore, we have also addressed the pathogenesis of this disease.

An orphan disease: IgG4-related spinal pachymeningitis: report of 2 cases

IgG4-related disease is relatively new disease entity and a rare one, and our knowledge of this entity continues to evolve. It was first described in the pancreas and since then has been described in virtually every organ. Spinal involvement resulting in pachymeningitis is rare, and there are only 8 reported cases of the same to date, with the cervicothoracic spine being the most commonly affected region.

The authors describe 2 cases in which the patients presented with spinal compression resulting in myeloradiculopathy (Case 1) and radiculopathy (Case 2). Imaging of spine in both cases revealed an ill-defined contrast-enhancing lesion at the lumbar level. Preoperatively, a diagnosis of spinal tumor was made, but intraoperatively no spinal tumor was found. The diagnosis was established histopathologically.

The disease has no particular defining features clinically or radiologically and can mimic common spinal tumors. It is important to accurately diagnose this rare entity because of its multisystem involvement and progressive course. Strict treatment guidelines have yet to be formulated. Although histologically this disease can mimic other inflammatory conditions, the presence of storiform fibrosis and an increased number of IgG4-positive plasma cells can help in clarifying the diagnosis.

Factors related to renal cortical atrophy development after glucocorticoid therapy in IgG4-related kidney disease: a retrospective multicenter study

Background

In immunoglobulin G4-related kidney disease (IgG4-RKD), focal or diffuse renal cortical atrophy is often observed in the clinical course after glucocorticoid therapy. This study aimed to clarify the factors related to renal atrophy after glucocorticoid therapy in IgG4-RKD.

Methods

We retrospectively evaluated clinical features including laboratory data and computed tomography (CT) findings before and after glucocorticoid therapy in 23 patients diagnosed with IgG4-RKD, all of whom were followed up for more than 24 months.

Results

Seventeen patients were men, and six were women (average age 62.0 years). Average follow-up period was 54.9 months. The average estimated glomerular filtration rate (eGFR) at diagnosis was 81.7 mL/min/1.73 m². All patients had had multiple low-density lesions on contrast-enhanced CT before glucocorticoid therapy, and showed disappearance or reduction of these lesions after it. Pre-treatment eGFR and serum IgE level in 11 patients in whom renal cortical atrophy developed 24 months after the start of glucocorticoid therapy were significantly different from those in 12 patients in whom no obvious atrophy was found at that time (68.9 ± 30.1 vs 93.5 ± 14.1 mL/min/1.73 m², P = 0.036, and 587 ± 254 vs 284 ± 263 IU/mL, P = 0.008, respectively). Pre-treatment eGFR and serum IgE level were also significant risk factors for renal atrophy development 24 months after the start of therapy with an odds ratio of 0.520 (per 10 mL/min/1.73 m², 95% confidence interval (CI) 0.273–0.993, P = 0.048) and 1.090 (per 10 IU/mL, 95% CI: 1.013–1.174, P = 0.022), respectively, in age-adjusted, sex-adjusted, serum IgG4 level-adjusted logistic regression analysis. Receiver operating characteristic curve analysis showed that eGFR of less than 71.0 mL/min/1.73 m² and serum IgE of more than 436.5 IU/mL were the most appropriate cutoffs and yielded sensitivity of 63.6% and specificity of 100%, and sensitivity of 90.9% and specificity of 75.0%, respectively, in predicting renal atrophy development.

Conclusions

This study suggests that pre-treatment renal insufficiency and serum IgE elevation predict renal atrophy development after glucocorticoid therapy in IgG4-RKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1175-y) contains supplementary material, which is available to authorized users.

Differential diagnosis of IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis

Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p=0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p<0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton's duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p<0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.

Interesting case of base of skull mass infiltrating cavernous sinuses

A man aged 35 years presented with chronic headache and earache of 1-year duration. He had progressive vision loss and diplopia since last 9 months. He also had pain over the face and episodic profuse epistaxis. On examination, perception of light was absent in the right eye and hand movements were detected at 4 m distance in the left eye. Imaging revealed a lobulated mass in the nasopharynx extending into the bilateral cavernous sinuses and sphenoid sinus with bony erosions. Biopsy of the nasopharyngeal mass revealed pathological features which are characteristic of IgG4 disease. His serum IgG4 levels and acute inflammatory markers were also elevated. The patient was started on oral corticosteroid therapy. Fever, headache and earache resolved early and there was gradual improvement in the vision of the left eye. After 6 months, visual acuity in the left eye was 6/9, but right eye visual acuity had no change. Follow-up imaging revealed a significant reduction in the size of the mass.

Diagnostic Challenges in a Case of IgG4-RD Affecting the Temporal Bone

Introduction:

Immunoglobulin G4–related disease (IgG4-RD) is a recently described fibroinflammatory condition with a characteristic histology. While IgG4-RD can affect a great variety of anatomical sites, it has been seldom described in the temporal bone.

Methods:

Herein, a case IgG4-RD occurring in the temporal bone of a 35-year-old woman is reported.

Discussion:

This case of IgG4-RD of the temporal bone proved a uniquely challenging diagnosis due to slightly atypical histology falling outside of “highly suggestive” criteria.

Conclusions:

We suggest that IgG4-RD remains a challenging diagnosis to reach despite increased awareness of the condition. We further suggest that clinicopathologic correlation remain the cornerstone of diagnosis as the spectrum of presentations of this newly described disease may be wider than previously anticipated.

IgG4-related disease causing facial nerve and optic nerve palsies: Case report and literature review

IgG4-related disease (IgG4-RD) is increasingly being recognized as an entity effecting the head and neck region. Although most commonly seen with salivary gland or paranasal sinus involvement, IgG4-RD may also involve the temporal bone and skull base. We report a rare care of a 61-year-old female with IgG4-RD presenting as synchronous lesions of the middle ear and middle cranial fossa with polyneuropathy of cranial nerves II, VI, and VII. Initial histopathological evaluation of her resected ear mass suggested a benign inflammatory process but no specific diagnosis. Her symptoms progressed over 10months prompting re-evaluation of the specimen and consideration of the IgG4-RD diagnosis. Key pathologic features included prominent lymphoplasmacytic population, storiform fibrosis, obliterative phlebitis, and IgG4 specific staining. The patient was treated with high-dose intravenous and oral steroids but was transitioned to azathioprine secondary to steroid-induced myopathy. Radiographic studies before and after treatment reveal marked improvement of the intracranial and extracranial disease. Correspondingly, her cranial neuropathies resolved. A high degree of clinical suspicion is necessary to diagnosis IgG4-RD. The diagnosis can be supported by elevated serum IgG, elevated IgG index, and pathognomonic histopathological findings. Primary treatment is with corticosteroids. However, immunotherapy using azathioprine or rituximab can be utilized in recurrent disease or patients with steroid intolerance.

Myocardial ischemia as presenting manifestation of IgG4-related disease: a case-based review

Coronary involvement in IgG4-related disease (IgG4-RD) has been scarcely reported, and myocardial ischemia as its presenting feature is even rarer. Here, we describe an additional case with novel and relevant observations. The patient was a previously healthy, middle-aged woman who presented to the clinic with new-onset typical angina. One tumefactive lesion encasing the left anterior descending artery was found during her workup. The most common underlying malignancies with secondary cardiac involvement were rationally ruled out. Symptoms persisted despite medical treatment, and she was therefore referred to surgery. Tumor excision was successfully performed, and she received coronary bypass grafting. IgG4-related coronary arteritis with pseudotumor formation was subsequently diagnosed following the comprehensive diagnostic criteria. This condition was clinically classified as active and circulating plasmablasts were found to be increased (5480/mL), even when these were determined 38 days after surgery. A PET/CT revealed an additional hypermetabolic lymph node. She was therefore treated with rituximab as induction therapy (two 1000 mg doses, administered 15 days apart). Three months later, her disease remained clinically inactive. Circulating plasmablasts were repeated and these had dropped to 0/mL. We thereafter review the current and pertinent literature on the topic, emphasizing the previous cases with similar presenting features (n = 7). We lastly suggest that IgG4-RD should be part of the differential diagnosis of any patient with tumefactive lesions surrounding the coronary arteries, since it can initially presented as sudden cardiac death.

IgG4-related hepatobiliary disease: an overview

IgG4-related hepatobiliary diseases are part of a multiorgan fibroinflammatory condition termed IgG4-related disease, and include IgG4-related sclerosing cholangitis (IgG4-SC) and IgG4-related hepatopathy. These diseases can present with biliary strictures and/or mass lesions, making them difficult to differentiate from primary sclerosing cholangitis (PSC) or other hepatobiliary malignancies. Diagnosis is based on a combination of clinical, biochemical, radiological and histological findings. However, a gold standard diagnostic test is lacking, warranting the identification of more specific disease markers. Novel assays - such as the serum IgG4:IgG1 ratio and IgG4:IgG RNA ratio (which distinguish IgG4-SC from PSC with high serum IgG4 levels), and plasmablast expansion to recognize IgG4-SC with normal serum IgG4 levels - require further validation. Steroids and other immunosuppressive therapies can lead to clinical and radiological improvement when given in the inflammatory phase of the disease, but evidence for the efficacy of treatment regimens is limited. Progressive fibrosclerotic disease, liver cirrhosis and an increased risk of malignancy are now recognized outcomes. Insights into the genetic and immunological features of the disease have increased over the past decade, with an emphasis on HLAs, T cells, circulating memory B cells and plasmablasts, chemokine-mediated trafficking, as well as the role of the innate immune system.

Sporadic occurrence of non-diagnosed IgG4-related disease in lymphoma patients with a previous Sjögren's syndrome diagnosis

BACKGROUND

IgG4-related disease (IgG4-RD) is a recently recognized fibro-inflammatory disorder, which may affect many organs, and often comes to clinical attention due to tumor-like organ swelling or is identified incidentally by specific biopsy findings. Typical histopathology of IgG4-RD is lymphoplasmacytic infiltration rich in IgG4 + plasma cells (PCs), storiform fibrosis, and obliterative phlebitis. Patients with sicca symptoms can be misdiagnosed as primary Sjögren's syndrome (pSS) instead of IgG4-RD because of clinical and histopathological similarities. Moreover, an association with lymphoma development is described in both diseases. This study investigated signs of IgG4-RD in a population-based cohort of patients diagnosed with pSS complicated by lymphoma.

METHODS

Patients with pSS and lymphoma diagnoses and available lymphoma specimens were identified by linkage with the Swedish Patient Register 1964-2007 and the Cancer Register 1990-2007 (n = 79). Clinical data and lymphomas were reviewed and the diagnoses evaluated. All lymphoma tissues and available minor salivary gland biopsies (n = 11) were immunostained for IgG4 + PCs and evaluated for other histopathological signs of IgG4-RD. In a case with specific findings of IgG4-RD, other available tissue specimens of the same patient were investigated for IgG4-RD.

RESULTS

Only one patient of 79 (1.3%) had >10 IgG4 + PCs/high power field (HPF) in the lymphoma tissue, an unspecified low-grade B-cell lymphoma localized in the submandibular gland. This patient also had other histopathological features of IgG4-RD in the lymphoma and a surgical lung biopsy taken five years before lymphoma diagnosis and, therefore, fulfilled the criteria for IgG4-RD. Occasional IgG4 + PCs (<10/HPF) without signs of IgG4-RD were observed in another six lymphomas. No IgG4 + PCs were identified in the minor salivary gland biopsies.

CONCLUSION

Histopathological findings of IgG4-RD may co-exist with low malignant B-cell lymphoma in patients with initially suspected pSS and may be associated with an underlying IgG4-RD.

Immunoglobulin G4-related disease mimicking an epidural spinal cord tumor: case report

The authors report a case of immunoglobulin G4-related disease (IgG4-RD) presenting as a paraspinal, epidural mass. This disease encompasses a host of autoimmune conditions that were previously thought to be separate entities. It is characterized by fibrosis, mediated by the aberrant proliferation and tissue invasion of IgG4-positive plasma cells, which can occur in any organ. As with other autoimmune conditions, it tends to be responsive to steroids and other immunosuppressants. It can rarely present as a tumefactive lesion of the central nervous system, creating the potential for misdiagnosis (given its similar radiological appearance to malignancy) and mistreatment. In 2015, a panel of experts convened to set forth guidelines for the diagnosis and treatment of IgG4-RD. In the case presented here, the patient initially presented with pain and weakness in the left upper extremity. Initial neuroimages revealed a contrast-enhancing mass extending from C-4 to T-1, invading the epidural spinal canal, encasing the exiting nerve roots, infiltrating the paraspinal musculature, and surrounding the left vertebral artery. A PET scan confirmed the mass was hypermetabolic, but results of fine-needle aspiration and CT-guided biopsy were inconclusive. Open biopsy yielded fibrotic tissue that met the pathological criteria for IgG4-RD: lymphoplasmacytic infiltrate, fibrosis in a storiform pattern, and obliterative phlebitis. The patient was treated with 2 doses of 4 mg of dexamethasone (Decadron) and then 50 mg of prednisone per day. Within 2 weeks, the mass was radiologically shown to have drastically decreased in size. The prednisone dose was decreased to 40 mg per day, and 100 mg of azathioprine per day was added. The patient continued to improve and the mass continued to decrease over the next 6 months. Currently, she has been weaned from all steroids and will be maintained on a daily dose of 100 mg of azathioprine.

Immunoglobulin G4-Related Ophthalmic Disease Involving the Sclera Misdiagnosed as Intraocular Tumor: Report of One Case

AIMS

Immunoglobulin G4 (IgG4)-related disease is known to have diverse clinical manifestations. We report a case of IgG4-related ophthalmic disease misdiagnosed as intraocular tumor.

METHODS

Case report.

RESULTS

A 41-year-old man was referred to our department with a diagnosis of intraocular tumor, presumably choroidal melanoma. Although MR imaging was compatible with choroidal melanoma, he had been observed periodically without treatment because fundus findings were not typical of melanoma and visual function was preserved. He was again referred to us 15 years later due to increased tumor size and visual field disturbance. Transscleral biopsy of the intraocular tumor was attempted to make a histopathological diagnosis. During the biopsy procedure, thick placoid tissue adhering to the sclera was found at a location consistent with the site of the elevated intraocular lesion. Histopathological examination of this extraocular material revealed proliferation of dense fibrous tissue with follicular proliferation of lymphocytes and plasmacytes. The plasmacytes were diffusely positive for IgG and IgG4. Serum IgG4 level was slightly elevated and no extraocular lesion was detected. Despite administration of systemic corticosteroids after biopsy, the intraocular mass was not reduced. Visual acuity of 20/20 has been maintained as of the last follow-up.

CONCLUSION

IgG4-related disease should be included in the differential diagnosis of intraocular elevated lesion.

Infraorbital nerve involvement on magnetic resonance imaging in European patients with IgG4-related ophthalmic disease: a specific sign

OBJECTIVES

To measure the frequency of infraorbital nerve enlargement (IONE) on magnetic resonance imaging (MRI) in European patients suffering from an IgG4-related ophthalmic disease (IgG4-ROD) as compared to patients suffering from non-IgG4-related ophthalmic disease (non-IgG4-ROD).

METHODS

From January 2006 through April 2015, 132 patients were admitted for non-lymphoma, non-thyroid-related orbital inflammation. Thirty-eight had both pre-therapeutic orbital MRI and histopathological IgG4 immunostaining. Fifteen patients were classified as cases of IgG4-ROD and 23 patients as cases of non-IgG4-ROD. Two readers performed blinded analyses of MRI images. The main criterion was the presence of an IONE, defined as the infraorbital nerve diameter being greater than the optic nerve diameter in the coronal section.

RESULTS

IONE was present in 53% (8/15) of IgG4-ROD cases whereas it was never present (0/23) in cases of non-IgG4-ROD (P < 0.0001). IONE was only present in cases where, on MRI, the inflammation of the inferior quadrant was present and in direct contact with the ION canal.

CONCLUSIONS

In European patients suffering from orbital inflammation, the presence of IONE on an MRI is a specific sign of IgG4-ROD. Recognition of this pattern may facilitate the accurate diagnosis for clinicians and allow for the adequate management and appropriate care of their patients.

KEY POINTS

• IONE on an MRI is a specific sign of IgG4-ROD. • IONE recognition allows for a quicker diagnosis and appropriate management. • IONE appears when inflammation is in direct contact with the ION canal.

Recognizing IgG4-related tubulointerstitial nephritis

PURPOSE OF THE REVIEW

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder affecting nearly all organs, including the kidney. Tubulointerstitial nephritis (IgG4-TIN) is the most common form of IgG4-related kidney disease (IgG4-RKD) and is the focus of this concise review.

OBJECTIVE

The study aims to describe when IgG4-TIN should be suspected and to summarize the diagnosis, treatment, and natural history of the disease.

SOURCES OF INFORMATION

Ovid MEDLINE, Google Scholar, and PubMed were searched for full-text English language articles up to January 2016. References included in the manuscript were chosen at the authors' discretion based on their relevance to the subject of the review.

FINDINGS

IgG4-TIN should be considered in patients presenting with abnormal urinalysis, abnormal kidney function, renal lesions on imaging, and elevated IgG, IgE, or hypocomplementemia. Diagnosis of IgG4-TIN requires a combination of histologic features (plasma cell-enriched TIN with >10 IgG4+ plasma cells/hpf, +/- TBM immune complex deposits in many cases) and at least one of the following:Characteristic radiologic findings (small peripheral low-attenuation cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement)Elevated serum IgG4 levelCharacteristic findings of IgG4-RD in other organs Other conditions such as lupus, vasculitis, diabetic nephropathy, and lymphoma must be excluded, as these can also present with IgG4+ plasma cells in the renal parenchyma. IgG4-TIN is generally responsive to steroids and B cell depletion with rituximab, but relapses are common and patients require close long-term follow-up.

LIMITATIONS

Available data on IgG4-TIN are from retrospective observational studies.

IMPLICATIONS

IgG4-TIN is a distinct and emerging subtype of interstitial nephritis. Nephrologists must be aware of this entity and how to definitively diagnose and treat it. Prospective studies and ideally multi-center clinical trials are needed to study the epidemiology, treatment, and natural history of this disease.

IgG4-related sialadenitis and Sjögren's syndrome

IgG4-related disease (IgG4-RD) has emerged as a new entity in the last decade. It comprises numerous conditions previously thought to be unrelated. Macroscopically, these diseases cause diffuse organ swelling and formation of pseudotumorous masses. Histopathologically, they are characterized by a lymphoplasmacytic infiltrate with increased IgG4+ plasma cells and storiform fibrosis. Despite rapid progress within the last years, our knowledge on these conditions is still fragmented. To date, more than forty organs have been reported to be included in IgG4-RD, and salivary gland involvement is amongst the most common organs affected [IgG4-related sialadenitis (IgG4-RS)]. Interestingly, IgG4-RS shares commonalities with Sjögren's syndrome (SS), like glandular enlargement, sicca symptoms, arthralgias, hypergammaglobulinemia, hypocomplementemia, and circulating antinuclear antibodies. Nonetheless, they differ in that the incidence of anti-Ro and anti-La reactivity is not frequently found in patients with IgG4-RS, their salivary glands are infiltrated by a large number of IgG4+ plasma cells and IgG4-RS symptoms respond promptly to steroids. The aim of this review was to describe the clinical, serological, histopathological and pathophysiological aspects of IgG4-RS in the context of IgG4-RD and highlight the differences between IgG4-RS and SS.

Immunoglobulin G4-related disease: a rare disease with an unusual presentation

IgG4‐RD can also present in the skeletal muscle, mimicking several other diseases. It is unusual for this relatively new classification of diseases to present in the muscles and can be mistakenly diagnosed as other autoimmune diseases rendering a delay in the appropriate management and progression of the disease.

Adult bile duct strictures: differentiating benign biliary stenosis from cholangiocarcinoma

Biliary epithelial cells preferentially respond to various insults under chronic pathological conditions leading to reactively atypical changes, hyperplasia, or the development of biliary neoplasms (such as biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and cholangiocarcinoma). Moreover, benign biliary strictures can be caused by a variety of disorders (such as IgG4-related sclerosing cholangitis, eosinophilic cholangitis, and follicular cholangitis) and often mimic malignancies, despite their benign nature. In addition, primary sclerosing cholangitis is a well-characterized precursor lesion of cholangiocarcinoma and many other chronic inflammatory disorders increase the risk of malignancies. Because of these factors and the changes in biliary epithelial cells, biliary strictures frequently pose a diagnostic challenge. Although the ability to differentiate neoplastic from non-neoplastic biliary strictures has markedly progressed with the advance in radiological modalities, brush cytology and bile duct biopsy examination remains effective. However, no single modality is adequate to diagnose benign biliary strictures because of the low sensitivity. Therefore, understanding the underlying causes by compiling the entire clinical, laboratory, and imaging data; considering the under-recognized causes; and collaborating between experts in various fields including cytopathologists with multiple approaches is necessary to achieve an accurate diagnosis.

Autoimmune Pancreatitis - A Riddle Wrapped in an Enigma

Autoimmune pancreatitis (AIP) was recognized as a clinical entity, at least in the West little more than 10 years ago. Since then, studies globally, and international collaboration, have led to important advances in our understanding of its clinical features, disease course, and management, although the aetiopathogenesis of this curious disease remains to be fully elucidated. Types 1 and 2 AIP have been described, of which type 1 is the commonest form, and best defined. International consensus now recognizes it as one of the many clinical manifestations of IgG4-related disease, and is now termed IgG4-related pancreatitis (IgG4-RP). The disease is not confined to a particular race, gender, or age, but often presents after the fifth decade in men. A common presentation is with jaundice due to low bile duct obstruction related to diffuse pancreatic enlargement (historically often leading to a misdiagnosis of cancer). Acute pancreatitis is unusual. Other organ involvement is a particular feature, including biliary disease, retroperitoneal fibrosis, generalized lymphadenopathy, renal, and lung involvement. No single test makes the diagnosis, and diagnostic criteria for type 1 AIP/IgG4-RP, which incorporate clinical, laboratory, radiological, pathological, and therapeutic parameters should be applied. A particular attempt should be made to make a histological diagnosis, which is characterized by an IgG4-positive lymphoplasmacytic infiltrate. Management is not based on randomized studies, but corticosteroids are the mainstay of treatment, providing rapid clinical and radiological benefit. However, clinical relapse is common (particularly in type 1 AIP, and in those with associated other organ involvement). Additional immunosuppression may be required, including azathioprine, and rituximab may play an emerging role. The disease course is variable, but loss of organ function (especially pancreatic exocrine failure and pancreatic atrophy) may occur.

Therapeutic approach to IgG4-related disease: A systematic review

To review the reported evidence on the therapeutic management of IgG4-related disease (IgG4-RD) in clinical practice.A systematic search of the literature was conducted. The primary outcome measured was the rate of efficacy of first-line therapeutic approaches. Secondary outcomes measured included the rate of disease relapse, the outcome of untreated patients, the rate of patients without drug therapy at the end of follow-up, the rate of side effects, and mortality. The MOOSE, AHRQ, STROBE, and GRACE recommendations/statements were followed.The results of the systematic search strategy yielded 62 studies that included a total of 3034 patients. Complete information about first-line therapeutic regimens was detailed in 1952 patients, including glucocorticoid-based regimens in 1437 (74%), drug-free regimens in 213 (11%), and other therapies in 38 (2%). No therapy (wait and see management) was reported in 264 (13%) patients. The efficacy of monotherapy with glucocorticoids was specified in 1220 patients, of whom 97% had a therapeutic response. Relapses, however, were reported in 464/1395 (33%) patients despite typically short follow-up periods. Therapeutic efficacy was reported in 219/231 (95%) of relapses treated with glucocorticoids, 56/69 (81%) of those treated with azathioprine, 16/22 (72%) of those treated with other immunosuppressive agents, and in the 9 cases treated with rituximab (100%). In 14 studies, the authors detailed the outcome of 159/246 patients with wait-and-see management; spontaneous improvement or resolution was reported in 68 (43%) cases. Wide heterogeneity was observed with respect to the first-line therapeutic approaches used for the different organ-specific disease subsets, including significant differences in the mean dose of glucocorticoids used.Nearly 70% of reported IgG4-RD patients are treated with oral glucocorticoids in monotherapy. However, the therapeutic management is heavily influenced by geographical, epidemiological, and clinical factors, especially with respect to the predominant organ affected. The frequency of glucocorticoid failure to induce sustained remissions both during and after treatment and the assessment of glucocorticoid toxicity in IgG4-RD require further study.

IgG4-related disease involving vital organs diagnosed with lip biopsy: A case report and literature review

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized new disease entity characterized by elevated serum IgG4 and infiltration of IgG4 plasma cells in affected tissues. Histological examination is essential for definitive diagnosis, as other pathological conditions can also present with serum IgG4 elevation. However, IgG4-RD frequently involves vital or internal organs that are difficult to perform biopsies. We herein report a unique case of IgG4-RD involving vital organs that could be successfully diagnosed by alternative lip biopsy, an accessible, little invasive procedure, despite no apparent manifestation demonstrating the involvement in labial salivary gland.A 60-year-old man with swelling of both submandibular glands and elevated serum creatinine level visited our hospital. His labial salivary glands appeared normal. His blood test showed high serum IgG4, and positron-emission computed tomography revealed abnormal uptake in submandibular glands, periaorta, and left kidney with hydronephrosis. We suspected him of IgG4-RD; however, the involved organs were difficult to approach for histological examination. Alternatively, we performed lip biopsy and proved massive infiltration of IgG4 plasma cells leading to the diagnosis with IgG4-RD. Treatment with prednisolone resulted in the remarkable improvement of organ involvements and the normalization of serum IgG4 level after 3 months. Prednisolone was gradually tapered without the relapse of disease.The early recognition and diagnosis of IgG4-RD is clinically important because delay in the treatment initiation leads to fibrosis with irreversible organ damage. Our case highlights the possibility that lip biopsy is a promising option for histological examination in patients with IgG4-RD in whom affected organs are difficult to access, leading to early diagnosis with appropriate treatment.

IgG4 deposits in pure and combined membranous lupus nephritis

The aim of this study is to determine the frequency and prognosis of IgG4 deposits in renal biopsy of patients with membranous lupus nephritis (MLN). This is a retrospective cohort study in which we included patients with class V alone or combined (III/V or IV/V) of lupus nephritis according to the 2004 ISN/RPS. All the patients included must have availability of renal tissue for immunohistochemistry analyses. We excluded other classes of lupus nephritis. The renal tissue was examined by a nephro-pathologist. We included 65 patients with MLN; of these, 24 (37 %) were class V, and the other had proliferative concomitant with membranous patterns. Seven renal specimens had IgG4 deposits (10 %). Patients with IgG4 deposits had higher levels of eosinophils in serum. All of the patients with IgG4 had renal involvement as first manifestations of systemic lupus erythematosus. The rate of renal failure was 42 and 43 % in IgG4 positive and negative, respectively, 28 % of IgG4 required renal replacement therapy. From a histological view, 42 % of IgG4 had evidence of arteriolar vasculitis in renal biopsies. Lupus patients with IgG4 deposits were more likely to have renal involvement as a first manifestation of systemic lupus erythematosus, and they course with a worse prognosis since they required more dialysis. Also, they have more probability of vascular inflammation on the renal biopsy.

Erdheim-Chester Disease as a Mimic of IgG4-Related Disease: A Case Report and a Review of a Single-Center Cohort

Immunoglobulin-G4 (IgG4)-related disease (IgG4RD) is a fibro-inflammatory disorder characterized by tissue-infiltrating IgG4 plasma cells, and, often, high serum IgG4. Several autoimmune, infectious, or proliferative conditions mimic IgG4RD. Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis, characterized by foamy histiocytic infiltration, fibrosis, and chronic inflammation. ECD and IgG4RD manifestations may overlap.A patient presented with huge fibrous retroperitoneal masses causing compression on neighboring structures; the case posed the challenge of the differential diagnosis between IgG4RD and ECD mainly because of a prominent serum and tissue IgG4 response.Retroperitoneal biopsy led to the diagnosis of ECD; the V600E BRAF mutation was found. Treatment with the BRAF inhibitor vemurafenib was started.Treatment failed to induce mass regression and the patient died after 3 months of therapy. Prompted by this case, we examined serum and tissue IgG4 in a series of 15 ECD patients evaluated at our center, and found that approximately one-fourth of the cases have increased IgG4 in the serum and often in the tissue.The differential diagnosis between IgG4RD and ECD can be challenging, as some ECD patients have prominent IgG4 responses. This suggests the possibility of common pathogenic mechanisms between ECD and IgG4RD.

Immunoglobulin G4-associated autoimmune hepatitis later complicated by autoimmune pancreatitis: A case report

Immunoglobulin G4 (IgG4)-associated autoimmune hepatitis (AIH) is a new disease entity with elevated levels of serum IgG4 and marked IgG4 positive plasma cell infiltration of the liver, and its clinical course remains unknown. A patient with IgG4-associated AIH who later developed autoimmune pancreatitis (AIP) is reported. A 73-year-old man was admitted to our hospital due to elevated liver transaminase levels, hypergammaglobulinemia and positive antinuclear antibody. A liver biopsy specimen showed severe interface hepatitis with marked lymphoplasmacytic infiltration without damage to the interlobular bile ducts, and a diagnosis of AIH was made. Abdominal computed tomography showed no abnormalities in the pancreas. Prednisolone therapy normalized the transaminase levels. Two years later, the patient developed AIP, which recurred after 5 years due to a reduction in the prednisolone dose. Three years later, he had a recurrence of AIH after discontinuation of prednisolone treatment. Evaluation of serum IgG4 levels and IgG4-bearing plasma cell infiltration of the liver at both the onset and recurrence of AIH showed that the serum IgG4 levels were 284 and 208 mg/dL, respectively, and the IgG4-bearing plasma cell infiltration levels were 30-40 cells/high-power field (HPF) per portal area and 4-10 cells/HPF per portal area, respectively. From these results, this case was finally diagnosed as IgG4-associated AIH. The course of this patient demonstrates two important clinical lessons: (i) IgG4-associated AIH can later be complicated by AIP; and (ii) discontinuation of prednisolone treatment can cause recurrence of IgG4-associated AIH.

IgG4-related retroperitoneal fibrosis: a newly characterized disease

Retroperitoneal fibrosis (RPF) is a rare disease characterized by chronic, nonspecific inflammatory and sclerotic or fibrotic tissue in the periaortic or periiliac retroperitoneum that encases adjacent structures. There will be a series of clinical manifestations once the proliferated fibrous tissues encase the abdominal aorta, iliac arteries and urinary duct. RPF is generally divided into two types: idiopathic retroperitoneal fibrosis (IRPF) without identified pathogenesis, making up about two-thirds of cases, and secondary retroperitoneal fibrosis. Recent studies on Immunoglobulin G4-related disease (IgG4-RD) reveal that abundant infiltration of IgG4 positive plasma cells is found in biopsies on the mass of RPF of some IRPF patients, which is identified as one spectrum of IgG4-RD and is named IgG4-related RPF. IgG4-related RPF is often misdiagnosed as retroperitoneal visceral malignancy and is treated with surgery. In addition, because of its good response to glucocorticoid, early detection and treatment is important. We review the definition, epidemiology, clinical features, diagnostic criteria, treatment and prognosis of IgG4-related RPF in this article to raise awareness of this newly characterized disease.

IgG4 Related Lung Disease

IgG4 related disease is a poorly understood immune mediated condition. Lung involvement is rare and difficult to diagnose and can mimic primary lung malignancy on imaging. A patient who was found to have an incidental lung lesion with risk factors for primary pulmonary malignancy is reported.

IgG4-related disease: a systematic review of this unrecognized disease in pediatrics

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition with an unclear pathophysiological mechanism affecting different parts of the body. If untreated, the disease can lead to fibrosis and irreversible organ damage. IgG4-RD mostly has been described in adults, hence it is generally unknown among pediatricians. This systematic search of the literature provides an overview of all reports published on IgG4-RD in children in order to create awareness of IgG4-RD in pediatrics and to emphasize the broad clinical presentation of this disease.

METHODS

A systematic literature search of Embase, Medline, Web-of-Science, PubMed publisher, Cochrane and Google Scholar was performed for case reports on IgG4-RD in children.

RESULTS

Of total 740 articles identified by the search, 22 case reports including 25 cases of IgG4-RD in children were found. The median age of the children was 13 years, of which 64 % were girls. IgG4-related orbital disease (44 %) and autoimmune pancreatitis type 1/IgG4-related pancreatitis (12 %) predominantly occurred. Less frequently, other manifestations as pulmonary manifestation, cholangitis and lymphadenopathy were also found. Almost all cases were histologically proven. Prednisone was the first choice of treatment leading to favorable clinical response in 83 % of the cases. Maintenance therapy with steroid sparing agents was required in 43 % of the cases needing therapy. Rituximab was successful in all 4 cases, whereas, the disease modifying rheumatic drugs (DMARDs) mycophenolate mofetil, azathioprine and methotrexate were effective in almost 50 % of the cases.

CONCLUSION

IgG4-RD in children is a generally unknown disease among pediatricians, but several pediatric cases have been described. Prednisone is the first choice of treatment leading to disease remission in the majority of the cases. DMARDs and rituximab are alternative effective steroid sparing agents with more positive evidence for the latter.

IgG4-related nephropathy

IgG4-related disease (IgG4-RD) is a recently recognized disorder, often with multiple organ involvement, characterized by dense tissue infiltration of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis and frequently elevated serum IgG4 concentration. The kidney can be involved either directly or indirectly. The most frequent direct renal manifestations of IgG4-RD are IgG4-related tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy. Retroperitoneal fibrosis (RPF) is another condition that is frequently IgG4-related and that can indirectly affect the kidney causing ureteral obstruction and hydronephrosis. Contrast-enhanced computerized tomography, magnetic resonance imaging and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography show different imaging findings and are useful tools for monitoring therapeutic response. Steroid treatment is the first line of therapy, but relapsing or refractory forms of the disease are frequently observed and require more aggressive therapeutic approaches. At our centre, we treated three cases of aggressive IgG4-related TIN and two cases of IgG4-related RPF with an intensified, immune suppressive protocol, obtaining good results without severe adverse effects.

Serum Concentrations of IgG4 in the Spanish Adult Population: Relationship with Age, Gender, and Atopy

Background and Aim

Serum IgG4 concentrations are commonly measured in clinical practice. The aim of this study was to investigate serum IgG4 concentrations in adults and their potential relationship with demographic, lifestyle, metabolic, and allergy-related factors.

Methods

Serum IgG4 concentrations were measured with a commercial assay in 413 individuals (median age 55 years, 45% males) who were randomly selected from a general adult population.

Results

Median IgG4 concentration was 26.8 mg/dL. Five out of the 413 individuals (1.2%) exhibited IgG4 concentrations >135 mg/dL, and 17 out of 411 (4.1%) exhibited an IgG4/total IgG ratio >8%. Serum IgG4 concentrations were significantly higher in males than in females and decreased with age. After adjusting for age and sex, serum IgG4 concentrations were not significantly influenced by alcohol consumption, smoking or common metabolic abnormalities (obesity and the related metabolic syndrome). Serum IgG4 concentrations were not significantly correlated with serum concentrations of proinflammatory cytokines and inflammation markers. Serum IgG4 concentrations were significantly correlated with IgE concentrations. Serum IgG4 concentrations tended to be higher in atopics (individuals with IgE-mediated sensitization to aeroallergens) than in non-atopics, particularly among atopics without respiratory symptoms. Serum IgG4 concentrations were not significantly correlated with total eosinophil blood count. Cases of IgG4-related disease were neither present at baseline nor detected after a median of 11 years of follow-up.

Conclusions

Studies aimed at defining reference IgG4 values should consider partitioning by age and sex. Further studies are needed to confirm the potential influence of atopy status on serum IgG4 concentrations.

IgG4-related disease: current challenges and future prospects

Immunoglobulin G4-related disease (IgG4-RD) represents an immune-mediated fibroinflammatory condition with a characteristic histopathological appearance that can affect various organs. Although numerous single-organ manifestations have been described more than a century ago, its systemic nature and unique features were only discovered in the last 2 decades, when IgG4-RD emerged as a new entity of disease. IgG4-RD is usually considered a rare disease, but its true epidemiology has not yet been fully clarified. Also, despite recent advances in the identification of the underlying immunological processes, its pathophysiology is only incompletely understood till now. The diagnostic workup of IgG4-RD is complex and usually requires a combination of clinical examination, imaging, histological, and serological analyses. However, no finding alone is specific for IgG4-RD. Therefore, its diagnosis requires careful interpretation of examination results in context with the patient’s clinical appearance as well as the exclusion of a broad variety of differential diagnoses. The past years brought rapid advances concerning this novel disease entity: diagnostic criteria, further insights into the underlying immunological processes, new biomarkers, and novel therapeutic approaches were proposed and widened the knowledge in the field of IgG4-RD. Still, a greater number of questions remain unanswered, and many recent developments require further discussion and proof from clinical trials. This review should give an overview on current knowledge and future perspectives in epidemiology, pathophysiology, diagnosis, and therapy of IgG4-RD.

Recovery of renal function after glucocorticoid therapy for IgG4-related kidney disease with renal dysfunction

BACKGROUND

Although renal dysfunction in IgG4-related kidney disease (IgG4-RKD) shows rapid resolution with glucocorticoid therapy, little is known about the appropriate initial glucocorticoid dose for induction therapy or long-term renal outcome.

METHODS

We retrospectively examined the differences in recovery of renal function according to the dose of glucocorticoid used for induction therapy and the long-term renal outcome in 43 patients with definite IgG4-RKD (mostly IgG4-tubulointerstitial nephritis), in whom the estimated glomerular filtration rate (eGFR) before glucocorticoid therapy was <60 ml/min.

RESULTS

Most patients were treated with glucocorticoid alone and had been maintained on glucocorticoid. The initial dose of prednisolone employed was ≤0.6 mg/kg/day (mean 0.47) in 27 patients (group L), and >0.6 mg/kg/day (mean 0.81) in 16 patients (group H). In both groups, the pretreatment eGFR was significantly improved at 1 month after the start of glucocorticoid therapy and the degree of improvement showed no significant inter-group difference. Relapse of IgG4-RKD occurred in 16.7% of the group L patients and 13.3% of the group H patients (p = 0.78). Among 29 patients who were followed up for over 36 months (mean 74 months) and had been maintained on glucocorticoid, none showed progression to end-stage renal disease and there was no significant difference between eGFR at 1 month after treatment and eGFR at the last review.

CONCLUSION

In glucocorticoid monotherapy for IgG4-RKD, a moderate dose is sufficient for induction, and recovery of renal function can be maintained for a long period on low-dose maintenance, although relapse can occur even in patients receiving maintenance therapy.