Fibrotic phenotype of IgG4-related disease.

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

Decreased absolute number of peripheral regulatory T cells in patients with idiopathic retroperitoneal fibrosis.

Objective: In order to determine whether the immune balance of T helper 17(Th17)/regulatory T(Treg) is related to the pathogenesis of idiopathic retroperitoneal fibrosis (IRPF), we analyzed the differences in peripheral blood lymphocytes, CD4+T cell subsets and cytokines between patients with IRPF and healthy people to clarify the CD4+T cell subsets, especially Treg cell subsets, and the role of cytokines in the pathogenesis of IRPF. Methods: This study included 22 patients with IRPF, 36 patients with IgG4-related diseases (IgG4-RD) without retroperitoneal fibrosis (RPF), and 28 healthy controls. The absolute numbers and percentage of peripheral blood lymphocyte subsets and CD4+T cell subsets in each group were detected by flow cytometry, and the serum cytokine level was detected by flow cytometric bead array (CBA). Results: Compared with the healthy group, the absolute value of B cells in peripheral blood of IRPF patients was significantly decreased, and T, natural killer (NK), CD4+ and CD8+ were not significantly abnormal. The absolute numbers of Th2 cells were lower than healthy group(p=0.043). In particular, the absolute numbers of Treg cells were significantly lower than healthy group(p<0.001), while the absolute numbers of Th17 cells increased(p=0.682). Th17/Treg was significantly higher than healthy group (p< 0.001). Cytokine analysis showed that the level of interleukin (IL)-4 in IRPF patients was higher than healthy group(p=0.011), IL-6, IL-10, IL-17, TNF-α and IFN-γ were significantly higher than healthy group (all p<0.001). Receiver operating characteristic (ROC) curves showed that IL-10 and TNF-α could distinguish bilateral ureteral dilatation in IRPF patients, with areas under the ROC curve (AUCs) of 0.813 (95% CI:0.607-1.000, p=0.026) and 0.950 (95% CI:0.856-1.000, p=0.001), respectively. IL-6 could distinguish bilateral ureteral obstruction, with an AUC of 0.861 (95% CI: 0.682-1.000, p=0.015). Conclusions: Our study showed that IRPF patients had reduced Treg cells and indeed had Th17/Treg imbalance, which may be related to the pathogenesis of the disease. The levels of IL-6, IL-10 and TNF-α appear to be associated with the progression of IRPF.

Surgical strategy of IgG4-related inflammatory abdominal aortic aneurysm with preoperative steroid therapy: A case report.

Immunoglobulin G4 (IgG4)-related disease, characterized by high serum IgG4 concentrations and IgG4-positive plasma cell infiltration, often presents as an inflammatory aneurysm. We herein report the case of a 78 year-old man, presenting with elevated inflammatory markers and IgG4 concentrations, who was diagnosed with IgG4-related inflammatory abdominal aortic aneurysm with dense perianeurysmal fibrosis. Before the surgical intervention, steroid therapy was administered to resolve his perianeurysmal inflammatory fibrosis. Half a year after the initiation of steroid therapy, there was an improvement in serum inflammatory markers and IgG4 concentrations, and the perianeurysmal fibrosis had regressed. Thus, we performed a surgical intervention including resection of the aneurysm and interposition with a prosthetic graft. Histopathological examination demonstrated few IgG4-positive plasma cells were distributed in the adventitia, which was suspected to be associated with the preoperative steroid therapy. This case study suggests preoperative steroid therapy is a useful therapeutic strategy for IgG4-related abdominal aortic aneurysm because it allows the use of open surgical procedures with reduced surgical risk.

Standardized approach to idiopathic retroperitoneal fibrosis: a comprehensive review of the literature.

BACKGROUND: Idiopathic retroperitoneal fibrosis (iRPF) is a rare fibro-inflammatory disease, characterized by inflammation of the abdominal aorta and its surrounding structures. The exact pathophysiology remains unclear. Diagnosis is often troublesome due to the non-specific and highly variable clinical presentation. Standardized treatment protocols are lacking. OBJECTIVE: This article presents a review on iRPF, addressing clinical and diagnostic modalities as well as its pathophysiology and the possible inclusion within the IgG4-related disease (IgG4-RD) spectrum. Finally, a diagnostic-therapeutic algorithm for a standardized approach to iRPF is proposed. METHODS: The PubMed Internet database was searched. Articles were selected based on the relevance of abstract, article type and impact of the journal. RESULTS: iRPF and IgG4-RD share a common autoimmune aetiology. Diagnostics are multimodal and based on imaging. Ruling out malignancy should be of primary concern. Complications are mostly of renal or vascular origin due to compression of retroperitoneal structures. Corticosteroids remain the first-line treatment regimen and are mostly successful, but evidence supporting alternative immunosuppressive and anti-inflammatory treatments is growing. Long-term therapy, as well as follow-up, is paramount in this chronic and often relapsing disease.

A Case of Immunoglobulin (Ig) G4-related Sclerosing Periaortitis Mimicking Mediastinal Malignant Tumor.

Sclerosing mediastinitis was first described by Oulmont in 1855. The aggressive fibro-inflammatory process that occurs in the mediastinum is the end result of a number of inflammatory processes. It is thought that hypersensitivity reactions to various antigens, autoimmune reactions, and idiopathic fibro-inflammatory responses play a role in the etiology of the disease. It has been shown in recent years that immonoglobulin (Ig) G4-related autoimmune diseases may lead to sclerosing mediastinitis. In this study, a rare case of Ig G4-related sclerosing periaortitis is presented in a 50-year male patient. The disease responded well to steroid treatment, but soon recurred following stoppage of the treatment. The treatment with deflazacort was started again; and he responded well. The lesion disappeared within six months of retreatment.

Concomitant presentation of IgG4-negative idiopathic retroperitoneal fibrosis and Addison's disease.

We describe a patient who was admitted to our medical centre with acute renal failure, hyponatraemia and hyperkalaemia. CT of the abdomen and pelvis showed a retroperitoneal mass with bilateral ureteral obstruction. Biopsy revealed fibrosis with inflammatory infiltrate, but rare IgG4-positive plasma cells. After placement of bilateral pigtail nephrostomy catheters, renal failure improved but metabolic derangements remained. Morning serum cortisol level was equivocal, but with blunted response on cosyntropin stimulation testing indicating adrenal insufficiency. Serology for 21-hydroxylase antibodies was strongly positive, supporting the diagnosis of Addison's disease. In addition to nephrostomy catheters for obstructive uropathy, idiopathic retroperitoneal fibrosis was treated with mycophenolate mofetil. Physiological doses of hydrocortisone and fludrocortisone for Addison's disease were also initiated. The patient continues to be monitored for regression of the mass. Based on review of the literature, this is the first reported case of IgG4-negative idiopathic retroperitoneal fibrosis presenting with autoimmune primary adrenal insufficiency.

Characteristics and prognosis of IgG4-related periaortitis/periarteritis: A systematic literature review.

OBJECTIVE: Immunoglobulin G4 (IgG4)-related disease is a systemic chronic fibroinflammatory disease that can affect almost every organ of the body. IgG4-related periaortitis/periarteritis is a newly recognized subset of IgG4-related disease, and its characteristics and prognosis remain unclear. We investigated the clinical characteristics and prognosis of IgG4-related periaortitis/periarteritis. METHODS: We performed a systematic literature review of IgG4-related periaortitis/periarteritis. Additionally, we have summarized the characteristics and prognosis of IgG4-related coronary arteritis. RESULTS: We investigated 248 patients with IgG4-related periaortitis/periarteritis. All studies reported the condition in elderly patients, and male predominance was observed. The infra-renal abdominal aorta and iliac arteries were the most commonly affected sites. Most reports showed the serum C-reactive protein elevation in this disease entity, in contrast to non-vascular IgG4-related disease. Based on radiological findings observed in 27 patients with IgG4-related coronary arteritis, vasculitic lesions were classified into 3 types: stenotic (67% of patients), aneurysmal (42%), and diffuse wall thickening type (92%). Serum IgG4 level, but not C-reactive protein level, was associated with the number of affected organs in IgG4-related coronary arteritis. Corticosteroid treatment with or without cardiac surgery or percutaneous coronary intervention was effective in most patients with IgG4-related coronary arteritis; however, 33% of patients showed an unfavorable clinical course including disease progression, relapse, or death. Pre-treatment stenosis and/or aneurysms were associated with progression of stenosis or aneurysm after corticosteroid treatment. CONCLUSION: Most clinical characteristics were similar between the IgG4-related periaortitis/periarteritis and the non-vascular IgG4-related disease groups; however, serum C-reactive protein level elevation was observed only in the former. Although corticosteroid treatment was effective, this disease can be life-threatening secondary to myocardial infarction, aortic dissection, and aneurysmal rupture. Pre-treatment evaluation of stenosis or aneurysms is important for predicting progression of stenosis or aneurysm after corticosteroid treatment.

IgG4-related Retroperitoneal Fibrosis: An Emerging Masquerader With a Sinister Presentation.

OBJECTIVE: Retroperitoneal fibrosis (RPF) is a rare proliferative fibro-inflammatory disease involving the soft tissues of the retroperitoneum. IgG4 related retroperitoneal fibrosis is an emerging entity which needs to be distinguished from idiopathic RPF. We describe a clinical case of IgG4 related RPF highlighting the importance of clinching this diagnosis. METHODS: A 70 year old female was referred to the outpatient department of our institute with complaints of fatigue, bilateral flank pain and loss of appetite for the past 1 month. The CT and PET scan demonstrated a uniformly enhancing bulky retroperitoneal mass causing bilateral hydroureteronephrosis. The biopsy from the mass lesion revealed IgG4 related disease. The patient was started on corticosteroids after percutaneous nephrostomy placement. RESULTS: Three months post induction of therapy, repeat PET-CT shows resolution of the mass with no FDG avid lesion. Serum IgG4 levels were reduced to normal (27 mg/dL) suggestive of response to treatment. The percutaneous nephrostomies were removed and the patient is doing well on maintenance dose of corticosteroids for her disease. CONCLUSION: The availability of serum IgG4 levels for monitoring treatment response and follow-up can curtail the repeated radiological imaging and associated contrast exposure as compared to idiopathic RPF. Secondly, the diagnosis of IgG4-related RPF shall alert the clinician to look out for extra-retroperitoneal diseases on follow up of this multi-organ disease.

Fibrocytes in Chronic Periaortitis: A Novel Mechanism Linking Inflammation and Fibrosis.

OBJECTIVE: Chronic periaortitis (CP) is a rare disease characterized by periaortic and periiliac fibroinflammatory tissue. The pathogenic mechanisms leading to tissue accumulation and activation of fibroblasts are unclear. This study was undertaken to explore the role of fibrocytes, circulating precursors of tissue fibroblasts, in patients with CP. METHODS: We studied 44 patients with newly diagnosed CP and 30 healthy controls. Circulating fibrocytes were identified as Col1+CD45+ cells using flow cytometry. Retroperitoneal tissue biopsy samples from 9 CP patients were stained with anti-type I procollagen, anti-CXCR4, and anti-CD45 antibodies and analyzed by confocal microscopy to detect tissue-infiltrating fibrocytes. Circulating levels and tissue expression of CXCL12, a CXCR4 ligand that promotes fibrocyte homing, were investigated using enzyme-linked immunosorbent assay and immunohistochemistry, respectively. We also characterized T helper polarization in biopsy samples from CP patients and measured serum levels of a panel of cytokines that are hallmarks of T helper responses and capable of influencing fibrocyte differentiation. RESULTS: The frequency of circulating Col1+CD45+ fibrocytes was higher in patients than in controls (P = 0.0371). CD45+proCol1+ and CXCR4+proCol1+ cells were detected in all examined biopsy samples from CP patients. Serum levels of CXCL12 were also higher in CP patients than controls (P = 0.0056), and tissue-infiltrating inflammatory cells intensely expressed CXCL12. Increased serum levels of Th2 cytokines (e.g., interleukin-13 [IL-13] and IL-10) were found in patients, and immunohistochemistry revealed a dominant infiltration of GATA-3+ cells, also indicating Th2 polarization; Th2-skewed responses are known to promote fibrocyte differentiation. CONCLUSION: Our findings indicate that fibrocytes are enriched in the peripheral blood of CP patients and infiltrate target lesions. The accumulation of fibrocytes in the pathologic tissue might be driven by CXCL12, and Th2-skewed immune responses are likely to facilitate their differentiation.

Chronic Periaortitis: an Update.

PURPOSE OF REVIEW: We aim to review traditional concepts and recent developments on the nosology, pathophysiology, clinical phenotypes and treatment of chronic periaortitis (CP). RECENT FINDINGS: CP is a rare disorder hallmarked by a periaortic fibro-inflammatory tissue. It can present as an isolated disease, but it can also be associated with other autoimmune and fibro-inflammatory lesions (e.g., fibrosing mediastinitis, sclerosing pancreato-cholangitis) that are part of the spectrum of IgG4-related disease. In a subgroup of patients, it also involves the thoracic aorta (so-called "diffuse periaortitis"), which supports the notion of an inflammatory disorder of large arteries. The pathogenesis of CP is multifactorial: recent studies have elucidated the predisposing role of immunogenetic variants and exposures to environmental agents such as smoking and asbestos. CP is a rare immune-mediated disease that affects the abdominal aorta and the iliac arteries and, in some cases, the thoracic aorta. It may overlap with manifestations of IgG4-related disease, and its treatment comprises glucocorticoids, conventional and biological immunosuppressive agents.

A Case of Aortic Stenosis with Serum IgG4 Elevation, and IgG4-Positive Plasmacytic Infiltration in the Aortic Valve, Epicardium, and Aortic Adventitia.

A 74-year-old man was admitted for preoperative screening of aortic stenosis. Five months before this admission, he was found to have elevated serum immunoglobulin G4 (IgG4; 2,010 mg/dL). Computed tomography (CT) showed a soft tissue mass surrounding the abdominal aorta, suggestive of IgG4-related periaortitis. CT coronary angiography showed perivascular thickening of the right coronary artery, and subsequent coronary angiography showed a multi-vessel disease. The patient underwent aortic valve replacement and coronary bypass surgery. Immunohistochemical analysis showed IgG4-positive plasmacytic infiltration in specimens from the aortic valve, epicardium, and aortic adventitia, suggestive of the possible role of IgG4-related immune inflammation for the pathogenesis.

Medical mirroring: granulomatosis with polyangiitis (formerly Wegener's) mimicking immunoglobulin-G4 related disease.

Granulomatosis with polyangiitis (GPA; formerly Wegener's) can present with clinical and histopathological features similar to those of immunoglobulin-G4 related disease (IgG4-RD), a recently described fibro-inflammatory condition. The ability of these two distinct entities to mimic each other closely creates significant pitfalls in diagnosis. We present a unique case in which GPA presented as a peri-aortic fibrotic mass in the retroperitoneum. The patient's other clinical features also overlapped with classic IgG4-RD disease manifestations, but the histopathology in two organs and the serological data confirmed the diagnosis of GPA. Rigorous histopathological review remains the gold standard for the diagnosis of GPA and the distinction of this entity from IgG4-RD and other mimickers.

A case of IgG4-related retroperitoneal fibrosis with multiple involvement.

To increase awareness of IgG4-related retroperitoneal fibrosis (IgG4-RRPF) and reduce clinical misdiagnosis. We report a 79-year-old man with multiple organs involvement of IgG4-RRPF, who developed right lower extremity edema, hemoptysis and fever. The abdomen computed tomography (CT) scan image showed lymph nodes enlargement. The positron emission tomography/CT scan image showed pancreatic malignancy with multiple nodal lymph node metastasis, lung fibroblast proliferation, and right lung apex bullae. The chest CT scan image showed pulmonary multiple lymph nodes with calcification in the mediastinum. Posterior peritoneum magnetic resonance imaging showed the body and tail of the pancreas parenchymatous mass. The serum IgG4 concentration was high. The fibrous connective tissue with IgG4-positive plasma cells infiltration in the left supraclavicular lymph node biopsy was found. Fiberoptic bronchoscopy showed diffuse alveolar hemorrhage, and the transbronchial lung biopsy found no cancer cells. The patient was treated with glucocorticoids and immunosuppressive agents. After 2 months treatment, the patient showed rapid improvement. This is a case of IgG4-RRPF with multiple organs involvement. Glucocorticoid is the first-line treatment.

Idiopathic Mediastinal Fibrosis: a Systemic Immune-Mediated Disorder. A Case Series and a Review of the Literature.

Mediastinal fibrosis is a rare disease characterised by fibrous proliferation in the mediastinum. It can be idiopathic or secondary to several conditions such as infections and malignancies. Anecdotal reports have described idiopathic mediastinal fibrosis (IMF) in association with other fibro-inflammatory or autoimmune diseases. We report nine new IMF cases recently seen at our Fibro-Inflammatory Disease Clinic and reviewed the IMF cases reported in the English language literature throughout 2006-2016. The purposes of our literature search were to assess the frequency of the association between IMF and other immune-mediated disorders and to analyse which disorders most often coexist with IMF. Of our nine IMF cases, one was associated with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, one with large-vessel arteritis, three with idiopathic retroperitoneal fibrosis (one of which was IgG4-related), one with pancreatitis and one with IgG4-related seminal vesicle involvement. The remaining two cases, in which IMF was not associated with any other disease, were both classifiable as IgG4-related. The literature review showed that, of the 84 IMF cases identified, 27 (32 %) were associated with other idiopathic autoimmune or fibro-inflammatory disorders, particularly small-vessel vasculitis, Behçet disease, retroperitoneal fibrosis and other conditions belonging to the IgG4-related disease spectrum. Based on our own data and the literature review, we conclude that IMF is often associated with other autoimmune or fibro-inflammatory diseases; therefore, its clinical management requires an accurate screening of associated conditions. Immune-mediated mechanisms may be shared by these disorders.

IgG4 Related Syndrome: Another Multiorgan Disease in the Interest Field of Internal Medicine.

BACKGROUND: IgG4-related disease is a rare, clinical and pathologic disease entity of unknown etiology. Its main features are increased serum concentrations of IgG4 > 1,35 g/l, lymphocyte and IgG4+plasma-cell infiltration within tissues, fibrosis or sclerosis. The classical presentation of IgG4-RSD is pancreatitis which is combined with the involvement of biliary ducts in 74 percent of patients. Extrapancreatic manifestations include: abdominal or mediastinal lymphadenopathy; the involvement of salivary glands and lacrimal glands, kidneys, lung, retroperitoneum. Since IgG4-related disease is a multiorgan lymphoproliferative syndrome, it requires a careful differential diagnosis from other distinct disorders (sarcoidosis, immune rheumatic diseases, hematologic diseases, malignancies). Another distinctive feature is a fairly fast response to steroids, that represents the first-choice therapy. Immunosuppressant drugs (azathioprine, mycophenolate mofetil, methotrexate) might be chosen as glucocorticoid-sparing medications or to maintain steroid-induced remission (Fig. 1). METHODS: We report the case of a 70-year-old man and we performed a brief review of loiterature. RESULTS: Our patient has a clinical history including bronchial asthma, aortic aneurysm, histologically confirmed retroperitoneal fibrosis causing hydroureteronephrosis, prostatitis, interstitial pulmonary fibrosis, sclerosing chronic pancreatitis (histologically documented), previous chronic cholecystitis (histologically confirmed), previous pericarditis, xeroftalmia, polyclonal hypergammaglobulinemia, eosinophilia. His serum IgG4 levels were significantly increased (5560 mg/dl). In regard to the above mentioned elements a systemic disease characterized by elevated serum levels of IgG4 and IgG4-positive lymphoplasmacytic infiltrative lesions in several tissues, was suspected. Immune-rheumatic diseases and infectious diseases were excluded. Steroid treatment was started achieving a significant swift response. CONCLUSION: Until now IgG4 related disease has been considered rare in the West and exclusive of Japanese and Korean countries, our case report leads us to reflect on the necessity to take into account this disease in patients with multisystemic involvement.

Chronic Tubulo-interstitial Pyelonephritis with Retroperitoneal Fibrosis.

A large proportion of patients with retroperitoneal fibrosis (RPF) have been labelled as having idiopathic RPF historically. Recent reports of a subset of these patients having a fibro-inflammatory condition with characteristic histology and good response to therapy has helped in renewed understanding of an old disease. A 40 year old man presented with vague abdominal discomfort of 5 months duration. Ultrasound examination revealed soft tissue thickening with calcification over lower abdominal aorta. CT scan characterized the lesion as a retroperitoneal mass encasing the aorta with an associated lesion in upper pole of left kidney. A laparoscopic surgery and biopsy of the mass lesions were performed. It was reported as chronic tubulo-interstitial disease with retroperitoneal fibrosis. In the post-operative period, patient developed fever with weight loss. An 18F-FDG PET-CT done revealed FDG-avid retroperitoneal mass lesion. Serum IgG-4 levels were elevated and review of biopsy revealed features of IgG4 related disease. Patient had good response to treatment with steroids and azathioprine.

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.

Liposarcoma masquerading as an inflammatory pseudotumor: a case report.

BACKGROUND: Distinguishing an atypical lipomatous tumor/well-differentiated liposarcoma from a benign lipomatous tumor on morphology alone can be difficult and there is an established role for MDM2 fluorescent in situ hybridization studies in making this differential diagnosis. There is no literature on the role for MDM2 fluorescent in situ hybridization studies in distinguishing between a well-differentiated liposarcoma with extreme fibrosis and a fibrosing inflammatory pseudotumor. CASE PRESENTATION: We report the case of a 76-year-old Australian woman initially diagnosed by an excision biopsy with a retroperitoneal fibrosing inflammatory pseudotumor. She was then diagnosed 5 years later with a pleomorphic undifferentiated sarcoma. Upon review of the original resection specimen, we were able to show that the tumor demonstrated MDM2 amplification. MDM2 amplification was also present in some adjacent bland adipose tissue, and also in the tumor recurrence as a pleomorphic undifferentiated sarcoma. CONCLUSION: Taken together, our findings provide strong evidence that the original tumor was a misdiagnosed well-differentiated liposarcoma with extreme fibrosis, and the pleomorphic undifferentiated sarcoma represented a recurrence of the same tumor with dedifferentiation.