IgG4-related disease: Advances in the diagnosis and treatment

Symmetrical polyarthritis in IgG4-related sialadenitis: a diagnostic challenge with seronegative rheumatoid arthritis

BACKGROUND

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition characterized by elevated IgG4 serum levels and tissue infiltration by IgG4-positive plasma cells. While often presenting with organ-specific involvement, such as sialadenitis or pancreatitis, its rheumatologic manifestations are rare and poorly understood. IgG4-RD often overlaps with autoimmune diseases such as rheumatoid arthritis (RA), posing a diagnostic challenge, particularly in seronegative presentations.

CASE PRESENTATION

We report a 48-year-old male presenting with progressive symmetrical polyarthritis mimicking rheumatoid arthritis. Laboratory findings showed elevated serum IgG4 levels and inflammatory markers, while autoantibodies (RF, ACPA, ANA, ANCA) were negative. A biopsy of a submandibular gland revealed dense lymphoplasmacytic infiltrates + fibrosis and IgG4-positive plasma cells, confirming the diagnosis of IgG4-RD. The patient responded well to a combination of glucocorticoids and methotrexate, with complete symptom resolution within one month and normalization of inflammatory markers.The therapeutic response observed in this case demonstrates the effectiveness of immunosuppression therapy in IgG4-RD management, while emphasizing the need for long-term follow-up.

DISCUSSION

This case underscores the diagnostic challenges in recognizing arthritis in a patient with biopsy-confirmed IgG4-related sialadenitis particularly when seronegative rheumatoid arthritis (RA) remains a plausible differential diagnosis.The overlapping clinical features and shared treatment responses make it challenging to attribute the arthritis to a single etiology.This report emphasizes the importance of considering IgG4-RD in the differential diagnosis of atypical arthritis presentations, particularly in patients with systemic manifestations. Histopathological confirmation, supported by clinical and serological evaluation, remains pivotal in guiding diagnosis and management. Long-term follow-up is essential to monitor for evolving features, including the potential development of overlapping conditions, and to ensure optimal treatment outcomes. Early recognition and tailored interventions are critical to preventing complications and improving patient quality of life.

CONCLUSION

IgG4-related disease (IgG4-RD) must be considered in the differential diagnosis of seronegative arthritis, especially when systemic symptoms or organ involvement are present. This case underscores the growing recognition of IgG4-RD in rheumatologic practice and the importance of a multidisciplinary approach to diagnosis and management. Clinicians should maintain heightened awareness of the overlap between IgG4-RD and rheumatoid arthritis (RA), advocating for the integration of histopathology, imaging, and serological testing to ensure accurate diagnosis. Additionally, long-term follow-up is essential to monitor disease progression, recurrence, development of new symptoms, and treatment response, ultimately enhancing patient care and outcomes.

Are there atypical sites of IgG4 related disease in head and neck region? Personal experience and literature review

PURPOSE

Immunoglobulin G4-related disease (IgG4-RD) is a complex systemic fibroinflammatory condition with different clinical manifestations affecting multiple organ systems. Despite its rarity, the disease presents diagnostic and therapeutic challenges due to its mimicry of malignancies and other immune-mediated disorders. The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease is the current state of art to confirm the diagnosis of IgG4-RD even in the absence of histological analysis. However, this classification excludes atypical sites, focusing on the more typical ones, even in case of histological confirmation. In the ENT field, several localizations of this disease have been described.

METHODS

We report two clinical cases at the Otolaryngology Unit of IRCCS San Martino Hospital, Genoa affected by IgG4-RD arising in atypical sides of the head and neck region. Additionally, we perform a clinical review of the current literature.

DISCUSSION

The review provides an extensive overview of IgG4-RD, encompassing epidemiology, clinical manifestations, diagnostic approaches, and therapeutic strategies. We discuss the evolution of diagnostic criteria, emphasizing the necessity of interdisciplinary collaboration among clinicians, radiologists, and pathologists for accurate diagnosis. Diagnostic imaging plays a crucial role, with characteristic radiological patterns aiding in the identification of affected organs. However, definitive diagnosis often requires histopathological confirmation, highlighting the importance of biopsy in challenging cases. We also focus on the treatment of IgG4-RD which poses significant challenges, with glucocorticoids remaining the cornerstone of therapy. Emerging steroid-sparing agents such as rituximab and Dupilumab, show promising results in refractory or recurrent disease.

CONCLUSIONS

IgG4-RD is a multisystemic fibroinflammatory disease that can potentially affect any part of the body. The 2019 ACR/EULAR 3-stage classification criteria for IgG4-RD considers only a few head and neck sites. Therefore, it is of paramount importance that neurosurgeons, head and neck surgeons, and oral and maxillofacial pathologists are familiar with the clinicopathological manifestations of IgG4-RD in these sites to avoid misdiagnosis and inappropriate treatment, which can lead to a decrease in patients' quality of life. To our knowledge, there are no risk factors or genetic predispositions. Further studies are needed to elucidate the pathophysiology of IgG4-RD with the aim of providing a targeted therapy that could spare steroid-related effects and reduce relapses.

IgG4-related disease mimicking a liver abscess

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

IgG4-Related disease with diffuse myopericardial involvement- value of CMR: a case report and literature review of cardiac involvement

BACKGROUND

IgG4-related disease is a fibro-inflammatory disorder with an unknown etiology, which can affect multiple organ systems, including the cardiovascular system. While most reported cases of cardiovascular involvement are primarily associated with the aorta, there have been sporadic reports of isolated cardiac involvement.

CASE PRESENTATION

This paper presents a documented case of IgG4-related systemic disease with symptoms indicative of restrictive cardiomyopathy. Subsequent Cardiac Magnetic Resonance imaging revealed diffuse myopericardial involvement, characterized by pericardial thickening and enhancement, accompanied by subepicardial and myocardial infiltration. Considering the rarity of cardiac involvement in our case, we conducted a thorough review of the existing literature pertaining to various patterns of cardiac involvement in IgG4-related disease, as well as the diagnostic modalities that can be employed for accurate identification and assessment.

CONCLUSIONS

This case report sheds light on the importance of recognizing and evaluating cardiac manifestations in IgG4-related systemic disease to facilitate timely diagnosis and appropriate management.

Immune-Mediated Hypertrophic Pachymeningitis and its Mimickers: Magnetic Resonance Imaging Findings

Hypertrophic pachymeningitis (HP) is a rare and chronic inflammatory disorder presenting as localized or diffuse thickening of the dura mater. It can be idiopathic or an unusual manifestation of immune-mediated, infectious, and neoplastic conditions. Although some cases may remain asymptomatic, HP can lead to progressive headaches, cranial nerve palsies, hydrocephalus, and other neurological complications, which makes its recognition a fundamental step for prompt treatment. Regarding the diagnosis workup, enhanced MRI is the most useful imaging method to evaluate dural thickening. This article addresses the MR imaging patterns of immune-mediated HP, including immunoglobulin G4-related disease, neurosarcoidosis, granulomatosis with polyangiitis, rheumatoid pachymeningitis, and idiopathic HP. The main infectious and neoplastic mimicking entities are also discussed with reference to conventional and advanced MR sequences.

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

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

Lung and Pleural Immunoglobulin G4-Related Disease: Two Contrasting Case Reports

Immunoglobulin G4-related disease (IgG4-RD) is an immunomediated disease that can virtually affect any organ. Despite the pancreas being known as the most frequently involved organ, pulmonary and pleural IgG4-RD is being increasingly reported. The authors present two cases of IgG4-RD diagnosed in the same year, with different presentations and outcomes, in which the lung and pleural involvement were essential for the diagnosis. Recognizing IgG4-RD as a possible cause of chronic pleural effusion and/or thickening and lung abnormalities is important for an early diagnosis and prognosis improvement.

American College of Rheumatology and the European League Against Rheumatism classification criteria for IgG4-related disease: an update for radiologists

IgG4-related disease (IgG4-RD) is an immune-mediated, multiorgan, chronic inflammatory disease. The three-step classification criteria proposed in 2019 by the American College of Rheumatology and the European League Against Rheumatism (ACR/EULAR) encompass a wide range of clinical, radiological, serological, and histopathological findings. The ACR/EULAR proposed a three-step classification process, i.e., entry step, exclusion step, and scoring system. Radiologists need to know that the radiological findings observed in the five domains of the lacrimal and salivary glands, chest, pancreas and biliary ducts, kidney, and retroperitoneum are independently weighted with different points in the scoring system. A total score < 20 points indicates that the patient should not be classified as having IgG4-RD; conversely, a total score ≥ 20 points indicates that the patient should be classified as having IgG4-RD. In this review, the 2019 ACR/EULAR classification criteria are discussed, focusing on the interpretation of each radiological item, with the aim of applying them to the diagnosis of IgG4-RD in clinical practice.

Sellar germinoma mimicking IgG4-related hypophysitis: a case report

BACKGROUND

The differential diagnosis of IgG4-related hypophysitis and other inflammatory diseases or tumors involving sellar region is challenging even after sellar biopsy. Sellar germinoma is usually infiltrated by lymphocytes or plasma cells, and may be confused with hypophysitis.

CASE PRESENTATION

A 36-year-old man with diabetes insipidus, elevated serum IgG4 level (336 mg/dl), and sellar mass was suspected to have IgG4-related hypophysitis, and no other lesion of IgG4-related disease was detected. After treated by prednisone and mycophenolate mofetil, the serum IgG4 decreased to 214 mg/dl. However, after withdrawal of the drugs, the IgG4 level increased to 308 mg/dl. Endocrine assessments revealed panhypopituitarism, and the sellar mass enlarged. Transsphenoidal sellar exploration and biopsy was conducted. Pathological examination showed that the lesion was germinoma with lymphocytes and plasma cells infiltration, and IgG4-staining was positive (70/HPF, IgG4/IgG ratio = 10%). The patient was then treated by cisplatin and etoposide. After four cycles of chemotherapy, the serum IgG4 was 201 mg/dl, and the sellar mass was invisible.

CONCLUSION

Sellar germinoma can mimic the clinical characteristics of IgG4-related hypophysitis. Poor response to glucocorticoids can be used as an exclusion criterion in the clinical diagnosis of IgG4-related hypophysitis.

Use of MRI signal intensity ratio to differentiate between autoimmune pancreatitis and pancreatic ductal adenocarcinoma

AIM

To evaluate the accuracy of the lesion-to-erector spinae signal intensity ratio (SIR) on magnetic resonance imaging (MRI) for distinguishing autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDA).

MATERIALS AND METHODS

The MRI data of 21 patients with AIP and 27 patients with PDA were analysed retrospectively, and the signal intensity in pancreatic lesions and erector spinae muscles at the same level on T2-weighted imaging (T2WI), arterial phase (AP) imaging, and delayed phase (DP) imaging was measured for calculation of SIRs.

RESULTS

The mean SIRs of the pancreatic lesions and erector spinae from T2WI, AP, and DP images of AIP patients were 0.96, 1.27, and 1.42, respectively, while those of PDA patients were 1.35, 0.80, and 0.91, respectively. The differences in the SIRs between the AIP and PDA groups were statistically significant (p<0.001), with corresponding area under curve (AUC) values of 0.925, 0.906, and 0.961, respectively. The optimal cut-off values for the SIRs on T2WI, AP and DP images were 1.21, 1.01, and 1.08, respectively. SIR values < 1.21 on T2WI, >1.01 on AP imaging, and >1.08 on DP imaging identified AIP with sensitivities of 85.7%, 90.5%, and 90.5%, respectively, and specificities of 81.5%, 74.6%, and 81.5%, respectively. The AUC values for SIRs did not differ significantly between T2WI and DP imaging or AP and DP imaging (Z = 0.778, p=0.436; Z = 1.279, p=0.201).

CONCLUSION

The SIRs of pancreatic lesions and erector spinae on T2WI, AP, and DP images can be used to differentiate AIP from PDA.

IgG4-Related Disease With Renal and Pulmonary Involvement

Immunoglobulin G4-related disease (IgG4-RD) is a rare immune-mediated disease affecting multiple organs and tissues. There is often the presence of elevated serum Ig4 subtype with histological evidence of lymphoplasmacytic infiltration, fibrosis, and phlebitis. The mainstay of treatment is steroids therapy. We report the case of a 66-year-old man presenting with acute on chronic renal failure and pulmonary nodules seen on PET-CT scan. He also had elevated serum IgG4 subclass and histological features in keeping with IgG4-RD. He failed steroid therapy but responded subsequently to rituximab with complete resolution of his symptoms.

Pericarditis as a manifestation of IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic, immune-mediated fibro-inflammatory disease that can affect virtually every organ system. It is usually insidious in onset and often mimics malignant or other inflammatory disorders. Diagnosis frequently requires a combination of clinical, serological, radiographic, and histopathological features, including increased serum-IgG4 levels and tissue infiltration of IgG4-positive plasma cells with associated fibrosis. Unlike more frequently affected sites, including the hepatobiliary system, salivary glands and retroperitoneum, pericardial involvement of IgG4-RD has only rarely been described. We report the case of a 76-year-old woman presenting with refractory pericarditis and imminent cardiac tamponade, successfully treated with therapeutic pericardiectomy. A diagnosis of IgG4-RD was made based on elevated serum-IgG4 levels and the presence of typical pericardial histopathological findings, meeting all 3 of the 2011 comprehensive diagnostic criteria for IgG4-RD. Following pericardiectomy, the patient remained in remission without a need for glucocorticoids or additional immunosuppressive therapy. Adding to this case, we reviewed the literature for previously described cases of IgG4-RD presenting with pericarditis and described their characteristics and the available treatment options. Our case-based literature review provides a clear overview of the diagnostic process for IgG4-RD and the need to apply classification criteria with the necessary caution, particularly in the case of rare disease manifestations, including pericarditis.

IgG4-related disease: an atypical presentation of steroid-responsive renal mass

IgG₄-related disease (IgG₄-RD) is a systemic fibroinflammatory disease characterised by dense lymphoplasmacytic infiltration rich in IgG₄-positive plasma cells, storiform fibrosis and obliterative phlebitis. Serum IgG₄ levels are typically elevated but half of the patients had normal serum IgG₄ levels. IgG₄-RD represents a spectrum of diseases that involve various organs such as the pancreas, liver, kidneys, and salivary glands often manifesting as diffuse organ enlargement or a mass-like lesion mimicking cancer. An increased incidence of malignancy among patients with IgG₄-RD has been reported. Thus, differentiating malignancy from IgG₄-RD manifestation is important as the treatment differs. Glucocorticoids are considered first-line therapy and should be started early to prevent fibrosis. Patients usually have an excellent clinical response to steroids, and poor steroid response is indicative of an alternative diagnoses such as malignancy. This case report describes a case of IgG₄-RD with renal mass in a young man that resolved with glucocorticoid therapy alone.

A Follow-Up Study of a European IgG4-Related Disease Cohort Treated with Rituximab

OBJECTIVES

IgG4-related disease (IgG4-RD) is a chronic fibro-inflammatory disorder affecting virtually any organ. Type 1 autoimmune (type 1 AIP) is its pancreatic manifestation. To date, steroids are considered the first-line pancreatitis treatment. The CD20-binding antibody rituximab (RTX) appears a promising steroid-sparing therapy, although long-term data are lacking. We aimed to bridge this gap with a cohort of IgG4-RD patients treated with RTX and to assess the potential value of the Responder Index (RI) as a discriminatory score for disease activity.

METHODS

We retrospectively evaluated 46 patients from a tertiary referral centre who were diagnosed with IgG4-RD and/or type 1 AIP according to the International Consensus Diagnostic Criteria or Unifying-AIP criteria between June 2006 and August 2019.

RESULTS

Patients resembled previous cohorts in terms of characteristics, diagnosis, and therapeutic response. Thirteen of the 46 patients with IgG4-RD/type 1 AIP were treated with RTX pulse therapy due to relapse, adverse reactions to steroids, or high-risk constellations predicting a severe course of disease with multi-organ involvement. Median follow-up after diagnosis was 52 months for all subjects, and 71 months in IgG4-RD patients treated with RTX. While patients in the RTX group showed no significant response to an initial steroid pulse, clinical activity as measured by the RI significantly decreased in the short-term after RTX induction. Within 16 months, 61% of patients relapsed in the RTX group but responded well to re-induction. Clinical and laboratory parameters improved equally in response to RTX.

CONCLUSION

RTX therapy in patients with IgG4-RD is an effective and safe treatment to induce treatment response and possible long-term remission. Repeated RTX administration after 6-9 months may be of value in reducing the risk of relapse. The RI appears to be a reasonable index to assess disease activity and to identify patients with IgG4-related disease who may benefit from B-cell-depleting therapy.

IgG4-related disease of the thyroid gland

IgG4-thyroid-related disease (TRD) represents an uncommon spectrum of diseases, with four subcategories established so far, IgG4-related Hashimoto's thyroiditis, fibrosing variant of Hashimoto's thyroiditis, Riedel's thyroiditis and Graves disease with elevated IgG4 levels. We report the case of a 59-year-old woman presenting with painless cervical swelling and hypothyroidism. Thyroid gland was enlarged and distinctively very hard, with reduced mobility. Neck ultrasonography showed multiple nodularity and diffuse thyroid enlargement, which on CT scan conditioned slight deviation of the airway. Fine-needle aspiration of the biggest nodule was suggestive of lymphocytic thyroiditis. She developed compressive symptoms and was submitted to total thyroidectomy. Histology of the thyroid revealed extensive areas of fibrosis, oncocytic cells and lymphoplasmacytic infiltrates. Immunohistochemistry confirmed the predominance of IgG4-secreting plasma cells. IgG4-TRD is characterised by a rapidly progressive and destructive thyroiditis process. Typical presentation can often mimic malignancy; hence, an opportune recognition of IgG4-TRD may avoid unnecessary burdens.

Long-term effects of intensive B cell depletion therapy in severe cases of IgG4-related disease with renal involvement

IgG4-related disease (IgG4-RD) is an immune-mediated disorder often showing elevated serum IgG4 concentrations, dense T and B lymphocyte infiltration, and IgG4-positive plasma cells and storiform fibrosis. We prospectively evaluated for 4 years 5 patients with histologically proven IgG4-RD of whom 3 had tubulointerstitial nephritis (TIN) and 2 had retroperitoneal fibrosis (RPF). They received an intensive B depletion therapy with rituximab. The estimated glomerular filtration rate of TIN patients after 1 year increased from 9 to 24 ml/min per 1.73 m2. IgG/IgG4 dropped from 3236/665 to 706/51 mg/dl, C3/C4 went up from 49/6 to 99/27 mg/dl, and the IgG4-RD responder index fell from 10 to 1. CD20+ B cells decreased from 8.7 to 0.5%. A striking drop in interstitial plasma cell infiltrate as well as normalization of IgG4/IgG-positive plasma cells was observed at repeat biopsy. Both clinical and immunological improvement persisted over a 4-year follow-up. Treating these patients who were affected by aggressive IgG4-RD with renal involvement in an effort to induce a prolonged B cells depletion with IgG4 and cytokine production decrease resulted in a considerable rise in eGFR, with IgG4-RD RI normalization and a noteworthy improvement in clinical and histological features. Furthermore, the TIN subgroup was shown not to need for any maintenance therapy.

Levels of serum IgG subclasses in patients with liver disease: A retrospective study

Viral and alcoholic liver disease, drug induced liver disease (DILD), primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) are among the most common liver diseases observed in clinical practice. These diseases lack unique clinical characteristics at the beginning of pathogenesis, which renders specific diagnosis difficult. Immunoglobulin G (IgG) subclasses are the main isoform of antibodies that can be found in the serum that serve important protective roles in immunity. The present study aimed to investigate the serum IgG subclass distribution in patients with the five common liver diseases aforementioned. The present study retrospectively recorded and analyzed the serum IgG subclass levels of different patients, who were grouped according to their clinical diagnosis. Serum IgG subclass levels were measured using immunonephelometric assays. IgG3 levels were found to be significantly increased whereas IgG4 levels were significantly decreased in patients with PBC. In patients with AIH, IgG1 levels were significantly increased. By contrast, IgG1/IgG level ratios in patients with viral liver disease were significantly increased. No clear pattern in the distribution characteristics of IgG subclasses could be observed in cohorts with alcoholic liver disease and DILD in the present study. Additionally, model for end-stage liver disease scores regarding IgG1 in patients with AIH shared a synergistic relationship. Anti-mitochondrial antibody subtype M2 (AMA-M2) and IgG3 in patients with PBC demonstrated a synergistic relationship. These results suggested that IgG subclasses may be used as biomarkers to further the understanding of liver disease, which could allow for early diagnosis.

Primary Immunoglobulin G4-Related Laryngeal Disease: A Case Series and Review of Literature

Objective:

Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognised cause of various systemic fibro-inflammatory conditions. However, laryngeal involvement as a primary feature is extremely rare. We aimed to report on a case series of such patients and examine the global literature relating to laryngeal involvement.

Methods:

Having previously reported a case of IgG4-RD laryngeal pseudotumour, we describe a case series of further 4 patients with primary laryngeal IgG4-RD managed by our UK quaternary airway service and provide a brief overview of laryngeal IgG4-RD.

Results:

Including our cases, 14 cases of primary laryngeal IgG4-RD have been reported. Vocal cord involvement is relatively uncommon. Repeat biopsies may be required to achieve histological diagnosis. Remission is achievable by commencement of immunomodulatory treatment, following which laryngeal reconstruction may be necessary.

Conclusion:

Laryngeal involvement is a rare presentation of IgG4-RD, itself a rare and difficult-to-diagnose condition. A high and prolonged index of suspicion is necessary from both surgical and pathological specialists for correct diagnosis and management.

The eosinophilic esophagitis and IgG4-related disease involving the esophagus

The study of eosinophilic esophagitis has become a dynamic field with an evolving understanding of the pathogenesis, diagnosis, and treatment. Immunoglobulin G4 (IgG4)-related disease exhibits systemic involvement but very rarely involves the esophagus. The article presents a clinical case: the history of ulcer and stricture of the esophagus in a young man of 17 years. The patient was finally diagnosed with IgG4-related and eosinophilic esophagitis and showed a good response to corticosteroid therapy. We herein report a rare case of dysphagia associated with IgG4-related disease and eosinophilic. We presented a review of modern data on the relationship of eosinophilic esophagitis and pathological IgG4-response.

Clinical manifestations, clinical course, and outcomes of immunoglobulin G4-related disease

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is an uncommon chronic systemic autoimmune disease, pathologically characterized by lymphoplasma cell and IgG4 plasma cell infiltration with storiform fibrosis. IgG4-RD is a new disease and is not yet widely recognized. The aim of this study was to describe the clinical manifestations and outcomes in Thai patients with IgG4-RD.

METHODS

This multicenter retrospective cohort study included patients aged ≥ 18 years who were diagnosed with IgG4-RD, according to the 2011 comprehensive or consensus diagnostic criteria, between 2000 and 2019 in four academic centers in Thailand. Baseline characteristics, laboratory and pathologic findings, treatments, and outcomes were systematically reviewed.

RESULTS

The study included 110 patients (71% male) with a mean age (SD) of 59.6 (13.3) years and median disease duration (interquartile range [IQR]) of 28.8 (14.6-53.5) months. Single organ involvement was observed in 60 patients (54.5%). Most patients (96%) had an IgG4 level of more than 135 mg/dL at presentation. Also, most (92%) were treated with corticosteroid (CS) alone or in combination with immunosuppressive agents. The most commonly used immunosuppressive agents were azathioprine (47%) and methotrexate (11%). Additionally, 20% required surgery, and 6.4% underwent stent insertion. One-quarter (26%), 37%, and 29% were in remission with successfully tapering CS, complete and partial response. Nevertheless, 22% relapsed, with a median time to relapse (IQR) of 22.2 (12.8-41.1) months.

CONCLUSION

IgG4-RD is a chronic systemic autoimmune disease with diverse manifestations, response to treatment, and outcomes. Most patients responded well to treatments but with a notable relapse rate.

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

BACKGROUND

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

CASE SUMMARY

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

CONCLUSION

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

Comparison of the Effects of Cyclophosphamide and Mycophenolate Mofetil Treatment Against Immunoglobulin G4-Related Disease: A Retrospective Cohort Study

Background: Although there are multiple ways to manage immunoglobulin G4-related disease (IgG4-RD), including treatment with glucocorticoids, "steroid-sparing" immunosuppressive drugs, or biologic agents, few clinical trials on IgG4-RD have been conducted. This study aimed to compare the efficacy and safety of glucocorticoids (GCs) combined with cyclophosphamide (CYC) or mycophenolate mofetil (MMF) in IgG4-RD patients. This cohort study was registered at ClinicalTrials.gov (ID: NCT01670695). Methods: This retrospective study included 155 IgG4-RD patients who received GCs with CYC or MMF at the Department of Rheumatology at Peking Union Medical College Hospital between January 2012 and July 2018. Propensity score matching (PSM) was conducted to match two groups of patients based on their baseline clinical characteristics. Treatment response, relapse rate, and drug safety were analyzed. The treatment response was evaluated based on complete response (CR), partial response (PR), and no change (NC), and the cumulative relapse rate and adverse events in each treatment group were compared using Kaplan-Meier curves and log-rank test, respectively. Results: Of the 155 IgG4-RD patients, 90 were treated with GCs plus CYC (group I) and 65 with GCs plus MMF (group II). After propensity score-matched (PSM) analysis, 108 patients were selected (54 in each group), 49 of whom had "definite" IgG4-RD, 8 "probable" IgG4-RD, and 51 "possible" IgG4-RD. At the last follow-up, the total response in groups I and II was 98.15 and 96.3%, respectively, and within 12 months, the cumulative relapse rate in group II was significantly higher than that in group I (14.8 vs. 3.7%, P = 0.046). Recurrence occurred at the paranasal sinus, lacrimal glands, skin, lung, pancreas, and bile ducts, and the relapsed patients achieved remission after switching immunosuppressants or/and increasing the GC dose. Conclusions: In IgG4-RD patients with internal organ involvement, GCs plus CYC or MMF are both effective with similar effects in disease response, while GCs plus CYC reduced the relapse rate better than GCs plus MMF.

IgG4-positive plasma cells in Hashimoto thyroiditis: IgG4-related disease or inflammation-related IgG4-positivity?

Despite the interest of researchers in IgG4-related disease (IgG4-RD), many questions still remain unanswered regarding the thyroid gland. We aimed to clarify the relationship between IgG4-positive plasma cells and the histopathological pattern in the Hashimoto thyroiditis (HT) in a Finnish series. HT specimens (n = 280) were retrieved from the Department of Pathology, Fimlab Laboratories. After re-evaluation, 82 (29%) cases (72 females and 10 males, 52 ± 17 years) with significant fibrosis were selected. CD38, IgG and IgG4 positivity in plasma cells was evaluated by immunohistochemistry. Adjusted IgG4-positive plasma cells per HPF > 20 and IgG4- to IgG-positive plasma cell ratio > 30% were adopted as threshold criteria and related to other morphological features. IgG4-positive HT group included 13 cases (15% from fibrotic HT, 4.6% from all HT, 50 ± 15 years, 11 females) with adjusted HPF count 30 ± 5 (23-40) IgG4-positive cells. IgG4-positivity significantly correlated with the presence of lobulation, oncocytic metaplasia and certain type of fibrosis, fibrosis spread outside the gland, lymphocytes/plasma cells epithelial penetration, the predominance of microfollicles and follicular atrophy in the present study. Despite the persisting uncertainty whether HT is IgG4-RD, HT with IgG4-positive plasma cells is histopathologically distinct entity with some geographic variability.

IgG4-related disease: a clinical perspective

IgG4-related disease (IgG4-RD) is a recently recognized fibro-inflammatory disorder that can affect almost any organ. Common presentations include major salivary and lacrimal gland enlargement, orbital disease, autoimmune pancreatitis, retroperitoneal fibrosis and tubulointerstitial nephritis. The main histopathological features are a dense, polyclonal, lymphoplasmacytic infiltrate rich in IgG4+ plasma cells, storiform fibrosis and obliterative phlebitis. The precise pathogenic mechanisms of IgG4-RD are still unclear. CD4+ T and B cells, including IgG4-expressing plasmablasts, constitute the major inflammatory cell populations and are believed to cause organ damage and tissue fibrosis. The diagnosis of the disease may be challenging and should be based on specific histopathological findings, typical laboratory and radiological aspects and an appropriate clinical context. The first-line treatment of IgG4-RD is based on glucocorticoids, which are usually efficacious. However, B cell depletion induced by rituximab has also been found to induce remission in steroid-resistant disease or has been used as steroid-sparing agent for relapsing disease. This review provides an update on clinical and therapeutic aspects of IgG4-RD.

Eosinophilic pancreatitis versus pancreatitis associated with eosinophilic gastroenteritis - a systematic review regarding clinical features and diagnosis

BACKGROUND

Over the past years, eosinophil infiltration involving the gastrointestinal tract and pancreas leading to eosinophilic pancreatitis, eosinophilic gastroenteritis and hypereosinophilic syndrome has been reported in the literature. We aimed to analyze and compare the features involving patients with eosinophilic pancreatitis and pancreatitis associated with eosinophilic gastroenteritis and to determine if there is a connection between the two disorders or if they in fact meet the diagnostic criteria for hypereosinophilic syndrome.

MATERIAL AND METHODS

The following search was performed in March 2019 on PubMed (MEDLINE) database using the medical terms "pancreatitis", "eosinophilic pancreatitis", "eosinophilic gastroenteritis" and "hypereosinophilic syndrome".

RESULTS

The search revealed 119 publications from 1970 onwards. A total of 83 papers were excluded, and the remaining 36 publications, consisting in case reports and case series, were analyzed. From 45 patients, 20 subjects with eosinophilic gastroenteritis developed pancreatitis, 20/45 had eosinophilic pancreatitis, and 5/45 hypereosinophilic syndrome involving the pancreas. There was no significant difference regarding clinical, laboratory and imaging features between the three groups, despite the multiple theories that explain the association of pancreatic and gastrointestinal eosinophilic infiltration. Although there was a strong resemblance between the three groups, histological evidence of eosinophilic gastrointestinal infiltration guided the treatment towards a less invasive way, while subjects with eosinophilic pancreatitis underwent pancreatic surgery to exclude potentially malignant lesions.

CONCLUSION

Although there are various theories that explain pancreatitis development in patients with eosinophilic gastroenteritis, hypereosinophilia diagnostic work-up should be taken into account in all patients with high number of blood eosinophils, even in those with eosinophilic pancreatitis in order to establish the diagnosis using a minimally invasive approach and to apply an adequate treatment.

An Overlapping Case of IgG4-Related Disease and Systemic Lupus Erythematosus

We are reporting a case of a 63-year-old Chinese female who presented to the rheumatology clinic with positive antinuclear antibody and unintentional weight loss along with lymphadenopathy. Further workup revealed eosinophilia, elevated anti–double stranded DNA, serum protein, and serum IgG4 (immunoglobulin G4). The patient was diagnosed with systemic lupus erythematosus. Due to the raised IgG4 level along with eosinophilia and diffuse lymphadenopathy, IgG4-related systemic disease was suspected. It was confirmed with IgG4 staining on lymph node biopsy. Our case is presenting the fact that systemic lupus erythematosus and IgG4-related disease can be present in the same patient with multiple overlapping features making accurate diagnosis challenging.

Identifying clinical subgroups in IgG4-related disease patients using cluster analysis and IgG4-RD composite score

Background

To explore the clinical patterns of patients with IgG4-related disease (IgG4-RD) based on laboratory tests and the number of organs involved.

Methods

Twenty-two baseline variables were obtained from 154 patients with IgG4-RD. Based on principal component analysis (PCA), patients with IgG4-RD were classified into different subgroups using cluster analysis. Additionally, IgG4-RD composite score (IgG4-RD CS) as a comprehensive score was calculated for each patient by principal component evaluation. Multiple linear regression was used to establish the “IgG4-RD CS” prediction model for the comprehensive assessment of IgG4-RD. To evaluate the value of the IgG4-RD CS in the assessment of disease severity, patients in different IgG4-RD CS groups and in different IgG4-RD responder index (RI) groups were compared.

Results

PCA indicated that the 22 baseline variables of IgG4-RD patients mainly consisted of inflammation, high serum IgG4, multi-organ involvement, and allergy-related phenotypes. Cluster analysis classified patients into three groups: cluster 1, inflammation and immunoglobulin-dominant group; cluster 2, internal organs-dominant group; and cluster 3, inflammation and immunoglobulin-low with superficial organs-dominant group. Moreover, there were significant differences in serum and clinical characteristics among subgroups based on the CS and RI scores. IgG4-RD CS had a similar ability to assess disease severity as RI. The “IgG4-RD CS” prediction model was established using four independent variables including lymphocyte count, eosinophil count, IgG levels, and the total number of involved organs.

Conclusion

Our study indicated that newly diagnosed IgG4-RD patients could be divided into three subgroups. We also showed that the IgG4-RD CS had the potential to be complementary to the RI score, which can help assess disease severity.

The 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-related disease

IgG4-related disease (IgG4-RD) can cause fibroinflammatory lesions in nearly any organ. Correlation among clinical, serological, radiological and pathological data is required for diagnosis. This work was undertaken to develop and validate an international set of classification criteria for IgG4-RD. An international multispecialty group of 86 physicians was assembled by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). Investigators used consensus exercises; existing literature; derivation and validation cohorts of 1879 subjects (1086 cases, 793 mimickers); and multicriterion decision analysis to identify, weight and test potential classification criteria. Two independent validation cohorts were included. A three-step classification process was developed. First, it must be demonstrated that a potential IgG4-RD case has involvement of at least one of 11 possible organs in a manner consistent with IgG4-RD. Second, exclusion criteria consisting of a total of 32 clinical, serological, radiological and pathological items must be applied; the presence of any of these criteria eliminates the patient from IgG4-RD classification. Third, eight weighted inclusion criteria domains, addressing clinical findings, serological results, radiological assessments and pathological interpretations, are applied. In the first validation cohort, a threshold of 20 points had a specificity of 99.2% (95% CI 97.2% to 99.8%) and a sensitivity of 85.5% (95% CI 81.9% to 88.5%). In the second, the specificity was 97.8% (95% CI 93.7% to 99.2%) and the sensitivity was 82.0% (95% CI 77.0% to 86.1%). The criteria were shown to have robust test characteristics over a wide range of thresholds. ACR/EULAR classification criteria for IgG4-RD have been developed and validated in a large cohort of patients. These criteria demonstrate excellent test performance and should contribute substantially to future clinical, epidemiological and basic science investigations.

IgG4-related pleural disease in a patient with a history of unknown origin acute pancreatitis: a case report and review of the literature

Immunoglobulin G4-related disease is a rare autoimmune systemic disease with the capability of involving every organ. The disease is microscopically defined by a diffuse tissular inflammation with an infiltration of IgG4 positive plasma cells in the affected organs. IgG4 disease has an increasing incidence in the last few years with a growing interest in its pathophysiology still misunderstood to date. Despite the growing recognition of this pathology, the literature still does not allow to propose a simple diagnostic algorithm. In this article, we present a case of a 56-year-old man with a history of unknown etiology acute pancreatitis and a unilateral pleural effusion.

Patterns of B Cell Repletion Following Rituximab Therapy in a Pediatric Rheumatology Cohort

Objective

To investigate the association between demographic characteristics, disease characteristics, the number of rituximab (RTX) rounds, and concurrent immunosuppression on B cell level repletion following RTX therapy.

Methods

A retrospective chart review of 112 children who met inclusion criteria and were treated with RTX at a single institution was performed. Demographic, clinical, and laboratory data were extracted and compared. CD19 levels were reviewed at 6 and 12 months post‐RTX with depletion defined as fewer than 10 cells/μL and complete repopulation to normal levels defined as 170 cells/μL or more.

Results

Among patients with CD19 levels, 48% of patients remained depleted at 6 months, 89% were repleted with 10 cells/μL or more by 12 months, and 46% remained below normal levels at 12 months following infusion. There was no significant association between the number of RTX rounds or underlying disease and persistent depletion below normal levels at 12 months following RTX infusion. Depletion at 6 months was associated with a 79% chance of persistent depletion below normal levels at 12 months. The association between concurrent cyclophosphamide (CYC) and repletion of 10 cells/μL or more at 6 (P = 0.091) and 12 months (P = 0.087) trended toward significance with no significant association between CYC and persistent depletion below normal levels.

Conclusion

RTX therapy for pediatric rheumatic diseases is well‐tolerated and results in variable repletion and normalization of B cell numbers at 6 and 12 months. B cell repletion in children is variable and independent of underlying disease and of the number of RTX infusions.

Pleomorphic Pulmonary Manifestations of IgG4-Related Disease

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory disorder which has been first reported in 2001 by Hamano and colleagues in a patient with autoimmune sclerosing pancreatitis. Almost every organ in the human body can be affected by IgG4-RD from infiltration with IgG4-positive plasma cells. Involvement of lungs with IgG4 is reported previously, but still, there is no clear picture of the pathophysiology behind lung involvement. Here, we are presenting a patient who has IgG4-RD presenting as pseudotumor of the lungs.

Retrospective single-centre analysis of IgG4-related disease patient population and treatment outcomes between 2007 and 2017

Objective

The aim was to gain a better understanding of the prevalence, organ involvement, clinical characteristics and long-term outcomes of medical and surgical treatments of IgG4-related disease (IgG4-RD).

Methods

Query of the Cleveland Clinic pathology database for IgG4 plasma cell staining between 2007 and 2017 yielded 1481 results, of which 57 cases were identified as highly likely (n = 28; 49%) or probable (n = 29; 51%) IgG4-RD by histopathological criteria and IgG4 serum concentrations. Patient demographics, type of treatment and outcomes were retrieved from medical records. Patients were designated as being in remission if indicated in the chart and/or symptom- and objective finding-free for >6 months, relapsed if symptoms/findings recurred after remission, active if no remission was achieved during follow-up, and as unable to determine if the duration of follow-up was <60 days or they were lost to follow-up.

Results

Of all patients who met the IgG4 staining criteria (n = 119), half (n = 57) satisfied the IgG4-RD histopathological criteria; 63% were males, age 57.9 ± 14.8 years. The average follow-up was 2.7 ± 2.2 years. The pancreas was the most affected organ in our cohort (26.4%). Almost half of the patients (45.6%; n = 26) were managed surgically, 21.1% (n = 12) medically, and 24.6% (n = 14) received both types of treatment. Medical treatment included prednisone (45.6%), MTX (5.3%), AZA (7%) and rituximab (8.8%). Remission was achieved by 77% of patients receiving surgical, 67% receiving medical and 72% receiving both treatments.

Conclusion

A histological diagnosis of IgG4-RD could be made in half of the patients who had IgG4⁺ plasma cells ≥10/high-power field or IgG4⁺/IgG⁺ ratio >40%. In our cohort, surgical treatment compared with medical treatment had a higher proportion of remission according to our outcome classification.

DIAGNOSIS OF ENDOCRINE DISEASE: IgG4-related thyroid autoimmune disease

IgG4-related disease (IgG4-RD) is fibro-inflammatory, immune-mediated, systemic disease recognized as a defined clinical condition only in 2001. The prevalence of IgG4-RD is 6/100 000, but it is likely to be underestimated due to insufficient awareness of the disease. The diagnostic approach is complex because of the heterogeneity of clinical presentation and because of rather variable diagnostic criteria. Indeed, high concentrations of IgG4 in tissue and serum are not a reliable diagnostic marker. The spectrum of IgG4-RD also includes well-known thyroid diseases including Riedel's thyroiditis, Hashimoto's thyroiditis and its fibrotic variant, Graves' disease and Graves' orbitopathy. Results from clinical studies indicate that a small subset of patients with the above-mentioned thyroid conditions present some features suggestive for IgG4-RD. However, according to more recent views, the use of the term thyroid disease with an elevation of IgG4 rather than IgG4-related thyroid diseases would appear more appropriate. Nevertheless, the occurrence of high IgG4 levels in patients with thyroid disease is relevant due to peculiarities of their clinical course.

IgG4-related disease in a patient with HIV infection

A 47-year-old HIV-positive man with good immune and virological status presented with chronic multiple enlarged lymph nodes, lung disease and eosinophilia. Radiologic tests showed enlarged cervical, thoracic and axillary lymph nodes, with interstitial lung damage. After several non-specific histologic studies, an elevated serum IgG4 level led us to request immunohistochemistry of a lymph node sample. The test confirmed the diagnosis of IgG4-related disease.

Temporal bone involvement of IgG4-related disease: a rare condition misleading to petrous apicitis causing lateral rectus palsy

IgG4-related disease (IgG4-RD) of temporal bone is rare and clinical manifestation mimics infection. A 19-year-old female presented with progressive left earache and intermittent left nasal obstruction. Then, she rapidly developed left lateral rectus palsy. The physical examination revealed mild redness of left tympanic membrane and a small nasal polyp from the left middle meatus. CT scan showed left petrous apicitis and enhancing sinonasal mucosa. Therefore, Gradenigo's syndrome was first considered. The empirical intravenous antibiotic was immediately prescribed and surgery was performed. The intraoperative pale soft tissue mass in middle ear and polyp in the left nasal cavity were sent for pathological examination and found positive immunohistochemical stains for IgG4 in plasma cells. Systemic corticosteroid, the first-line treatment, was started and her symptoms were finally recovery.

IgG4-related disease in endocrine practice

IgG4-related disease is a set of symptoms resulting from a chronic, usually multiple organ inflammatory condition which affects various organs. It consists of lymphoplasmacytic infiltrations with attendant fibrosis and deep vein thrombosis. Frequently observed tissue lesions are accompanied by elevated IgG4 levels in serum. The etiopathogenesis of the lesions is of multifactor character and the clinical manifestation of the disease is highly diverse. The diagnostic process is based on the patient's medical history, clinical examination and additional tests, including a histopathological examination of the infected organ's tissues. Almost forty different locations of the disease have been reported, including disorders of the endocrine system. IgG4-related endocrinopathies are quite rare. However, it is likely that the diagnosis is under-reported due to lack of awareness of this clinical entity. Despite increasing interest in the subject, there are not enough reliable studies evaluating the link between IgG4-RD and endocrine disorders.

Sex disparities in clinical characteristics and prognosis of immunoglobulin G4–related disease: a prospective study of 403 patients

Objectives

To study the impact of sex on the clinical presentation of IgG4-related disease (IgG4-RD).

Methods

We prospectively enrolled 403 newly diagnosed IgG4-RD patients. We compared the demographic features, clinical manifestations, organ involvement, laboratory tests and treatment outcomes between female and male patients. The organs involved were divided into superficial organs (salivary glands, lacrimal glands, orbit, sinus and skin) and internal organs (all the other organs). The patients treated with glucocorticoids with or without additional immunosuppressants were included in the assessment of treatment outcomes, and potential confounding factors were corrected by propensity score matching or multivariate Cox regression analysis.

Results

Female patients showed younger age at both symptom onset and diagnosis, and a longer interval between symptom onset and diagnosis. Allergy history, Mikulicz’s disease and thyroiditis were more common in female patients, while autoimmune pancreatitis, sclerosing cholangitis and retroperitoneal fibrosis were more common in male patients. In accordance, female patients more frequently presented with superficial organ involvement, while male patients more frequently had internal organ involvement, and the discrepancy was more prominent in the patients with older age. Male sex was associated with higher peripheral eosinophils, CRP and IgG4 levels at baseline. In response to glucocorticoid-based therapies, male sex was associated with a higher IgG4-RD responder index during follow-up as well as a greater risk of relapse (hazard ratio 3.14, P = 0.003).

Conclusion

Our study revealed the sex disparities in clinical characteristics of IgG4-RD, and indicated that male sex was independently associated with worse prognosis in response to glucocorticoid-based therapies.

IgG4-related sclerosing mesenteritis, a rare condition that causes abdominal pain

The identification of IgG4-related disease as a distinct immune-mediated condition encompassing disorders that were traditionally seen as idiopathic has been a revolution in the diagnostic and therapeutic algorithm in several medical fields. This condition usually involves multiple organs (isolated organ involvement is uncommon except in the pancreas) with characteristic histopathological findings. We report a case that was assessed due to abdominal pain and subsequently diagnosed with IgG4-related sclerosing mesenteritis. A comprehensive work-up of the case ruled out other conditions and a diagnosis of IgG4-related sclerosing mesenteritis was made according to radiographic and histopathological criteria.

IgG4-related disease mimicking pancreatic cancer: Case report and review of the literature

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Pancreatic masses pose a diagnostic challenge, and cancer has to be always considered.

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IgG4-related disease is a rare cause of pancreatic masses.

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Biopsy from the pancreas is not always required if histopathology from a more accessible peripheral site lesion confirms the diagnosis.

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Multiorgan involvement and aortitis should raise suspicion of IgG4-related disease.

Introduction

Most patients with pancreatic masses pose a diagnostic challenge when a benign lesion is suspected, and often, resection is needed before a benign diagnosis is confirmed.

Presentation of case

A 57 years old male patient presented with a pancreatic head mass, obstructive jaundice and submandibular lymph node enlargement. He also had a history of recurrent eye pain and redness, skin lesions, and benign prostatic hypertrophy. MRI showed a pancreatic head mass with double duct sign, aortic thickening, bilateral renal lesions, diffuse lymph node enlargement, and prostatic enlargement. FDG-PET/CT demonstrated abnormal uptake corresponding to the MRI lesions, and there were elevated IgG4 levels on blood investigations. Biopsy of an inguinal lymph node revealed infiltrates with IgG4 plasma cells, consistent with the diagnosis of IgG4 disease. The patient was treated with IV steroids and showed significant improvement.

Discussion

IgG4 related disease is a rare entity that is characterized by lesions that show heavy infiltration with IgG4 positive plasma cells, storiform fibrosis, and obliterative phlebitis. The pancreas is the most commonly involved organ, but several other organ systems are involved, and this helps in clinical suspicion of the diagnosis. A biopsy from any easily accessible site that shows the characteristic histological features is sufficient for diagnosis. Patients respond quickly to steroids, but recurrence is frequent.

Conclusion

IgG4 related disease is a rare cause of pancreatic tumorous lesions that need a high index of suspicion for diagnosis and should be differentiated from pancreatic neoplastic lesions.

IgG4-related disease: review of the histopathologic features, differential diagnosis, and therapeutic approach

Immunoglobulin G4-related disease (IgG4-RD) is an uncommon disorder that demonstrates characteristic clinicopathologic features including sclerosing lesions with storiform fibrosis, increased IgG4+ plasma cells with an increased IgG4+/IgG+ plasma cell ratio, obliterative phlebitis, and often an increased serum IgG4 level. This review summarizes the characteristic histopathologic and clinical features of IgG4-RD with detailed discussion of the histopathologic characteristics of the most commonly involved anatomic sites. We also present recent advances in our understanding of the pathophysiologic mechanisms of IgG4-RD and discuss updates on the treatment, prognosis, and outcomes of this rare disease, including discussion of the possible association between IgG4-RD and malignancy.

IgG4-related kidney disease: the effects of a Rituximab-based immunosuppressive therapy

IgG4-related disease (IgG4-RD) is a recently recognized disorder, characterized by elevated serum IgG4 concentrations, dense tissue infiltration of IgG4-positive plasma cells and storiform fibrosis. Treatment is usually based on steroids, however, relapses and long-term adverse effects are frequent. We prospectively studied 5 consecutive patients with histologically-proven IgG4-RD and renal involvement, treated with an extended Rituximab protocol combined with steroids. Two doses of intravenous cyclophosphamide were added in 4 patients. Five patients with IgG-RD were investigated: three had tubulointerstitial nephritis (TIN), while two had retroperitoneal fibrosis (RPF). In the patients with TIN, renal biospy was repeated after 1 year. In the patients with TIN, estimated glomerular filtration rate (eGFR) at 12 months increased from 9 to 24 ml/min per 1.73 m²; IgG/IgG4 decreased from 3,236/665 to 706/51 mg/dl; C3/C4 increased from 49/6 to 99/27 mg/dl; CD20⁺ B-cells decreased from 8.7% to 0.5%; Regulatory T-cells decreased from 7.2% to 2.5%. These functional and immunologic changes persisted at 24 months and in two patients at 36 months. A repeat renal biopsy in the patients with TIN showed a dramatic decrease in interstitial plasma cell infiltrate with normalization of IgG4/IgG positive plasma cells. The patients with RPF showed a huge regression of retroperitoneal tissue. In this sample of patients with aggressive IgG4-RD and renal involvement, treatment aimed at depleting B cells and decreasing antibody and cytokine production was associated with a substantial, persistent increase in eGFR, and a definite improvement in immunologic, radiologic and histological parameters.