Reducing relapse through maintenance steroid treatment can decrease the cancer risk in patients with IgG4-sclerosing cholangitis: Based on a Japanese nationwide study.

OBJECTIVE: IgG4-related sclerosing cholangitis (IgG4-SC) is recognized as a benign steroid-responsive disease; however, little is known about the risk of development of cancer in patients with IgG4-SC and about how to counter this risk. DESIGN: We conducted a retrospective review of the data of 924 patients with IgG4-SC selected from a Japanese nationwide survey. The incidence, type of malignancy, and risk of malignancy in these patients were examined. Then, the standardized incidence ratio (SIR) of cancer in patients with IgG4-SC was calculated. RESULTS: Relapse was recognized in 19.7% (182/924) of patients, and cancer development was noted in 15% (139/924) of patients. Multivariate analysis identified only relapse as an independent risk factor for the development of cancer. In most of these patients with pancreato-biliary cancer, the cancer developed within 8 years after the diagnosis of IgG4-SC. The SIR for cancer after the diagnosis of IgG4-SC was 12.68 (95% confidence interval [CI] 6.89-8.79). The SIRs of cancers involving the biliary system and pancreas were 27.35 and 18.43, respectively. The cumulative survival rate was significantly better in the group that received maintenance steroid treatment (MST) than in the group that did not; thus, MST influenced the prognosis of these patients. CONCLUSION: Among the cancers, the risk of pancreatic and biliary cancers is the highest in these patients. Because of the elevated cancer risk, surveillance after the diagnosis and management to prevent relapse are important in patients with IgG4-SC to reduce the risk of development of cancer.

The Role of Symptom Duration and Serologic Factors in the Relapse of IgG4-Related Ophthalmic Disease following Surgery: A Retrospective Cohort Study.

IgG4-related disease (IgG4-RD) affects multiple organs and is characterized by immune-mediated inflammation and fibrosis; IgG-RD affecting orbital tissue is known as IgG4-related ophthalmic disease (IgG4-ROD). This research is aimed at exploring whether symptom duration and common serologic factors, such as IgG, IgE, and eosinophils, are potential risk factors for IgG4-ROD patient relapse after surgery and identifying possible causes of the positive correlation between symptom duration and relapse. This retrospective cohort study included 40 IgG4-ROD patients after surgery. Auxiliary inspection results were obtained before surgery and during follow-up, and relapse risk factors were identified based on previous studies. We used the Spearman rank correlation test to reveal the relationship between symptom duration and relapse time and identified the optimal cutoff value for symptom duration by X-tile. Then, we divided the patients into the long-duration and short-duration groups. Kaplan-Meier survival analyses and log-rank tests were performed to identify the relationship between symptom duration and relapse using X-tile software. Finally, we studied the relationship between previously studied relapse risk factors and symptom duration. The survival curves of the long-duration and short-duration groups were obviously different, and the baseline serum IgG, IgE, and eosinophil levels and asthma concomitant rate were significantly different between the long-duration and short-duration groups. Furthermore, the baseline serum IgG (r = 0.485, P = 0.002), IgE (r = 0.350, P = 0.037), and eosinophil (r = 0.6535, P < 0.0001) levels were positively correlated with symptom duration. Our study shows that IgG4-ROD symptom duration is significantly positively correlated with relapse rate and negatively correlated with relapse time. Symptom duration was positively correlated with serum baseline IgG4, IgE, and eosinophil levels and asthma history, which were potential risk factors for disease relapse. We recommended that IgG4-ROD patients with symptom durations greater than 96 months continue to receive maintenance steroid therapy longer than 1 year postsurgery to reduce the relapse rate.

Overexpression of IgG2 in patients resembling IgG4-related disease with normal IgG4.

IgG4-Related Disease (IgG4-RD) results from tissue infiltration by IgG4-expressing plasma cells and lymphocytes, leading to fibrosis and organomegaly. Clinical presentation is remarkably variable according to organ involvement, and high IgG4 serum concentration, initially considered a diagnostic hallmark of IgG4-RD, tends to be forgone as an indispensable criterion for its diagnosis; it can indeed be absent in some patients, highlighting the diversity of presentation of this dysimmune condition. Nevertheless, elevation of IgG4 serum concentration in suggestive settings remains an argument in favour of IgG4-RD, and while other IgG subclasses can be elevated, this biological feature lacks any diagnostic value. We retrospectively studied 9 patients (5 females, 4 males, 31-81 years old) for whom a diagnosis of IgG4-RD had been considered, based on clinical, imaging or histological criteria, but appeared to display abnormally high serum IgG2 while IgG4 levels were normal. Increased serum IgG1 in one case and increased IgG3 in another one were also noticed. Immunohistochemical analyses of intracellular immunoglobulins could be performed on tissue lymph node biopsies from 2 patients, which demonstrated strong infiltration with IgG2-expressing plasma cells. Thus, overexpression of IgG2 subclass may highlight cases of dysimmune disorders resembling IgG4-RD, although the disease trigger might be different, notably infectious. We suggest measuring all serum IgG subclass levels in patients with features consistent with IgG4-RD.

Immunoglobulin G4-related disease and idiopathic multicentric Castleman's disease: confusable immune-mediated disorders.

IgG4-related disease (IgG4-RD) and idiopathic multicentric Castleman's disease (iMCD) are both rare systemic immune-mediated disorders. However, the pathogenesis differs markedly between the two diseases and differing therapeutic strategies are adopted: IgG4-RD is treated using a moderate dose of glucocorticoids or rituximab, while iMCD therapy involves an IL-6-targeted approach. Nonetheless, some clinical features of IgG4-RD and iMCD overlap, so differential diagnosis is sometimes difficult, even though the classification and diagnostic criteria of the diseases require careful exclusion of the other. The key findings in IgG4-RD are high IgG4:IgG ratio, allergic features and germinal centre expansion involving T follicular helper cells, while iMCD involves polyclonal antibody production (high IgA and IgM levels), sheet-like mature plasma cell proliferation and inflammatory features driven by IL-6. The distribution of organ involvement also provides important clues in both diseases. Particular attention should be given to differential diagnosis using combined clinical and/or pathological findings, because single features cannot distinguish IgG4-RD from iMCD. In the present review, we discuss the similarities and differences between IgG4-RD and iMCD, as well as how to distinguish the two diseases.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Accompanied by IgG4-Tubulointerstitial Nephritis with Underlying Sjögren Syndrome: A Case Report and Review of Literature.

OBJECTIVE: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of autoimmune multisystemic diseases characterized by necrotizing inflammation of small vessels and the presence of circulating ANCA. The prevalence of overlap AAV with other autoimmune diseases was low. CASE REPORT: We report a case of a 54-year-old woman who presented with a 20-year-history of sicca symptoms, the presence of anti-Ro/SS-A, anti-La/SS-B antibodies, myeloperoxidase -ANCA (MPO-ANCA), significant increase of serum IgG4 level, microscopic hematuria, non-nephrotic proteinuria, and progressive renal dysfunction. A renal biopsy showed pauci-immune necrotizing glomerulonephritis with crescents with severe tubulointerstitial nephritis (TIN) which shows extensive infiltration of IgG4-positive plasma cells. Considering these findings and the clinical course, the disease was considered more likely to be MPO-ANCA-associated vasculitis accompanied by IgG4-TIN with underlying primary Sjögren syndrome (pSS). CONCLUSION: This report shows a possible unusual disease overlap of MPO-ANCA-associated vasculitis and IgG4-TIN with underlying pSS.

Peripheral B-Cell Immunophenotyping Identifies Heterogeneity in IgG4-Related Disease.

Objectives: To elucidate heterogeneity of IgG4-related disease (IgG4-RD) based on B cell immunophenotyping. Methods: Immunophenotyping of 4 B-cell subsets in peripheral blood from patients with active IgG4-RD (aIgG4-RD, n=105) was performed using flow cytometry to get preliminary B-cell heterogeneity spectrum. Then 10 B-cell subsets were characterized in aIgG4-RD (n = 49), remissive IgG4-RD (rIgG4-RD, n = 49), and healthy controls (HCs, n = 47), followed by principal components analysis (PCA) and cluster analysis to distinguish B-cell immunophenotypes and classify IgG4-RD patients into subgroups. Results: Cluster analysis identified two endotypes in 105 aIgG4-RD patients based on 4 B-cell subsets: Group1 with higher Breg and naive B cells (n = 48), and Group2 with higher plasmablasts and memory B cells (MBCs) (n = 57). PCA indicated that aIgG4-RD consisted of plasmablast-naive B cell and MBCs-Breg axes abnormalities. There was a negative relationship between naive B cells and disease activity. Both plasmablasts and MBCs were positively associated with serological biomarkers. Cluster analysis stratified aIgG4-RD patients into 3 subgroups based on 10 B-cell subsets: subgroup1 with low MBCs and normal Breg, subgroup2 with high MBCs and low Breg, and subgroup3 with high plasmablasts and low naive B cells. Patients in subroup2 and subgroup3 were more likely to be resistant to treatment. Conclusion: Patients with aIgG4-RD can be divided into 3 subgroups based on B cell heterogeneity. The B cell immunophenotyping could help elucidate the pathogenesis of IgG4-RD, identify patients with potential refractory IgG4-RD, and provide important information for the development of new therapies.

Immune Dysregulation in IgG4-Related Disease.

Immunoglobin G4-related disease (IgG4-RD) is one of the newly discovered autoimmune diseases characterized by elevated serum IgG4 concentrations and multi-organ fibrosis. Despite considerable research and recent advances in the identification of underlying immunological processes, the etiology of this disease is still not clear. Adaptive immune cells, including different types of T and B cells, and cytokines secreted by these cells play a vital role in the pathogenesis of IgG4-RD. Antigen-presenting cells are stimulated by pathogens and, thus, contribute to the activation of naïve T cells and differentiation of different T cell subtypes, including helper T cells (Th1 and Th2), regulatory T cells, and T follicular helper cells. B cells are activated and transformed to plasma cells by T cell-secreted cytokines. Moreover, macrophages, and some important factors (TGF-ß, etc.) promote target organ fibrosis. Understanding the role of these cells and cytokines implicated in the pathogenesis of IgG4-RD will aid in developing strategies for future disease treatment and drug development. Here, we review the most recent insights on IgG4-RD, focusing on immune dysregulation involved in the pathogenesis of this autoimmune condition.

Regional disturbance of the distribution of T regulatory cells and T helper cells associated with irregular-shaped germinal centers in immunoglobulin G4-related sialadenitis.

Although many germinal centers (GCs) have been reported in immunoglobulin (Ig) G4-related disease, the significance of GCs in IgG4-related disease has not received attention. Both T follicular regulatory cells (Tfr), which are regulatory T cells (Treg) in GCs, and T follicular helper cells (Tfh) produce the cytokine interleukin (IL)-10 and regulate GC development. In whole-slide image analysis in surgical specimens using immunohistochemistry, IgG4-related sclerosing sialadenitis (IgG4-SS, n = 17) was characterized by markedly numerous, large, and irregular-shaped GCs with increased IL-10 + cells and Tfr and Tfh in the total area of the salivary gland compared with controls, including patients with chronic sialadenitis (n = 17) and Sjögren syndrome (n = 15). In particular, the central area of GC in IgG4-SS showed a higher Tfr number and Tfr/Tfh ratio than controls. The number of Tfr in the central area was significantly correlated with the number of IgG4 + plasmacytes and the number, size, and irregularity of GCs. In the mantle area, which surrounds GCs, IgG4-SS showed a higher Treg number and Treg/T helper cells (Th) ratio than controls. In IgG4-SS, the Treg/Th ratio was highest in the mantle area outside GCs and the Tfr/Tfh ratio was highest in the central area inside GCs. However, in controls, the Treg/Th ratio gradually decreased from outside to inside GCs. Our findings reveal that the morphological abnormality of GCs and the characteristic localization and altered balance of Treg and Th in the different compartments of inside and outside GCs would be the novel hallmarks of IgG4-SS.

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.

Immunoglobulin G4-Related Disease Responder Index Correlates With the Risk of 1-Year Relapse in Type 1 Autoimmune Pancreatitis.

OBJECTIVES: Type 1 autoimmune pancreatitis (AIP) is a manifestation of immunoglobulin G4-related diseases (IgG4-RD). To evaluate the activity of the disease, the IgG4-RD responder index (RI) has been created. This study evaluated the IgG4-RD RI as prognostic factor of 1-year disease relapse. METHODS: Patients diagnosed with type 1 AIP between January 2012 and December 2016, with available magnetic resonance imaging and IgG4 dosage, were enrolled. Immunoglobulin G4-RD RI was calculated at baseline (time 0), and at 3 to 6 and 12 to 18 months after the end of steroid therapy (time 1 and time 2, respectively). RESULTS: Thirty-three patients were included in the study. Immunoglobulin G4-RD RI was 8.9 (standard deviation [SD], 3.8) at time 0, 2.4 (SD, 3.1) at time 1 (P < 0.0001 vs time 0), and 4.2 (SD, 3.9) at time 2 (P = 0.02 vs time 1). Fourteen patients who relapsed within 1 year showed a higher mean value of IgG4-RD RI at time 0 (10.9; SD, 4.3) versus 19 who did not (7.4; SD, 2.6; P = 0.012). This difference was observed also at time 2 (6.8 vs 2.1; P = 0.002). CONCLUSIONS: Immunoglobulin G4-RD RI correlates with type 1 AIP disease activity, and it predicts disease relapse within 1 year.

Immunoglobulin G4-Related Aortitis and Severe Aortic Valve Stenosis Treated With Transcatheter Aortic Valve Replacement and Immunosuppression.

IgG4-related disease is an immune-mediated fibro-inflammatory disorder with multisystemic involvement. Aortitis and peri-aortitis are the most common cardiovascular manifestations of the disease. We present the case of a 65-year-old man with symptomatic severe aortic stenosis and concomitant IgG4 aortitis. The diagnosis was confirmed by IgG4 serum levels, positive positron emission computed tomography (PET-CT) scans, and pathology from mediastinal dissection. Surgical aortic valve replacement (SAVR) was unfeasible owing to extensive mediastinal fibrosis, and transcatheter aortic valve replacement (TAVR) was successfully performed. As ascending aorta access for SAVR in IgG4 aortitis with long-run fibrosis entails a high risk of mortality, TAVR could be considered in certain suitable patients.

Co-occurrence of IgA nephropathy and IgG4-Tubulointersitial nephritis effectively treated with tacrolimus: a case report.

BACKGROUND: Cases of concurrent immunoglobulin A nephropathy (IgAN) and IgG4-related tubulointerstitial nephritis (IgG4-TIN) are rare and previous case reports have lacked important data. KDIGO suggests a treatment with systemic glucocorticoids in IgAN patients. Glucocorticoids are recommended as the first-line therapy for IgG4-TIN. The use of tacrolimus as a long-term maintenance treatment has not been described. We report the case of a man who developed IgAN and IgG4-TIN without abnormalities in extra-renal tissue, without renal function abnormalities or impairment as well, and was treated by tacrolimus as a long-term maintenance during 45 months follow-up. CASE PRESENTATION: A 56-year-old Chinese man first presented to our hospital with the chief complaint of foamy urine for 1 year and hematuria for 3 months, with a medical history of hypertension. Testing revealed a notable increase in serum IgG4 level without abnormalities in renal function or imaging, or in dysfunction other organs. Renal biopsy showed mesangial extracellular matrix proliferation, increased mesangial cell numbers and infiltration of plasma cells. Immunofluorescence showed mesangial positivity for IgA and C3. Immunohistochemistry staining showed widespread IgG4 and increased CD38 and CD138 expression. Electron microscopy showed immune complexes located on the tubular basement membrane. He was diagnosed with IgAN and IgG4-TIN. He received glucocorticoids, leflunomide and tacrolimus to induce remission. He was given tacrolimus as long-term maintenance treatment. When tacrolimus was temporarily withdrawn, proteinuria recurred. After resuming tacrolimus therapy, he again entered complete remission. After 45 months of therapy, he remains in complete remission and the serum IgG4 level is normal. CONCLUSIONS: The finding of concurrent IgAN and IgG4-TIN without abnormalities in renal function, imaging or extra-renal tissue is rare and their coexistence may be coincidental. Long-term treatment with tacrolimus proved effective and he has remained in remission during 45 months follow-up.

Allergic Aspects of IgG4-Related Disease: Implications for Pathogenesis and Therapy.

IgG4-related disease (IgG4-RD) is a rare systemic fibroinflammatory disease frequently associated with allergy. The pathogenesis of IgG4-RD is poorly understood, and effective therapies are limited. However, IgG4-RD appears to involve some of the same pathogenic mechanisms observed in allergic disease, such as T helper 2 (Th2) and regulatory T cell (Treg) activation, IgG4 and IgE hypersecretion, and blood/tissue eosinophilia. In addition, IgG4-RD tissue fibrosis appears to involve activation of basophils and mast cells and their release of alarmins and cytokines. In this article, we review allergy-like features of IgG4-RD and highlight targeted therapies for allergy that have potential in treating patients with IgG4-RD.

Coronary (peri)-arteritis in patients with IgG4-related disease: A case series from the Central Anatolia Region of Turkey.

OBJECTIVE: Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized fibro-inflammatory disease which affects many systems, as well as the cardiovascular system. Identifying the coronary involvement like periaortitis, coronary periarteritis and pericarditis is important, as they often cause unfavorable outcomes. METHODS: Eighty-one patients with IgG4-RD were retrospectively evaluated for symptomatic coronary artery involvement from Hacettepe University Vasculitis Research Center (HUVAC) database. The demographic, laboratory, radiologic and clinical characteristics of the patients were assessed. RESULTS: Among 81 patients with IgG4-RD, 6 patients (M/F:5/1) had coronary artery involvement. The patients' median age was 57 and serum IgG4 levels were above normal except for one case. All patients with coronary arteritis revealed an increased coronary vessel wall thickening and stenotic lesions. The coronary aneurysm and pericarditis were observed in half of the patients. Immunosuppressive treatments were given to all the patients and most of them followed in stable condition. CONCLUSION: Coronary arteritis is a rare but notable manifestation of IgG4-RD. Although coronary periarteritis can cause significant morbidity and mortality, it seems better results can be achieved with early diagnosis and treatment.

T-Cell-Driven Fibroinflammation Inducing Follicular Dedifferentiation in Alopecia Areata and IgG4-Modified Disease.

ABSTRACT: The definition of IgG4-related diseases incorporates a broad range of systemic diseases particularly a subset dominated by fibroinflammation. CD4+cytotoxic T cells have emerged as the major driving force for the fibroinflammation, and the pathogenetic role of IgG4 still remains to be determined. Cutaneous involvement is uncommon and is not well defined as elevated tissue IgG4 plasma cells are not a specific marker and prominent cutaneous fibroinflammation is often absent in cutaneous disease. We report the case of a patient with longstanding alopecia universalis and severe atopic dermatitis who presented with diffuse induration and mottled dyspigmentation of his scalp. Multiple scalp biopsies revealed diffuse interfollicular fibroinflammation and IgG4 plasma cells with induction of distinctive dedifferentiated follicles not seen in alopecia areata. This complex case may provide insight into the role of specific subsets of T cells not only in respect to the fibroinflammation linked to IgG4-related diseases but also the capacity to modify disease, follicular stem cell activation, immune privilege, cytotoxicity in alopecia areata, and the presence of atopy that may have contributed to the pathogenesis of this case.

Proteomic analyses of plasma-derived exosomes in immunoglobulin (Ig) G4-related disease and their potential roles in B cell differentiation and tissue damage.

OBJECTIVE: To investigate the proteomic profiles of plasma exosomes isolated from patients with immunoglobulin (Ig) G4-related disease (IgG4-RD) and to determine their potential roles in B cell differentiation and tissue damage. METHODS: One hundred untreated IgG4-RD patients and 135 sex- and age-matched healthy controls (HCs) were enrolled in this study. A combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and tandem mass tag (TMT)-label quantitation was used for proteomic profiling. Differentially expressed proteins were validated by Western blot, enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR) analyses. B cell activation, apoptosis, differentiation and reactive oxygen species (ROS) production were analyzed by flow cytometry. We also analyzed the correlations between differentially expressed complement proteins and laboratory parameters. RESULTS: A total of 178 differentially expressed proteins were identified in plasma exosomes in IgG4-RD patients compared with HCs, and these proteins were enriched predominantly in the complement cascade pathway. Furthermore, reduced expression levels of complement components C3 and C5 in IgG4-RD were correlated with clinical parameters. Following stimulation with IgG4-RD plasma exosomes, the percentages of naïve B cells decreased, while those of memory B cells and plasmablasts increased; the levels of cytochrome c, somatic (CYCS) and downstream complement system activation also increased. Moreover, ROS production was greater in B cells of IgG4-RD patients than in those of HCs. In affected submandibular glands, the BCR signalling pathway was activated, and exosomes were enriched. CONCLUSION: Proteomic profiling revealed that plasma exosome proteins may participate in the pathogenesis of IgG4-RD through complement activation and may be involved in B cell differentiation and activation of the B cell auto-oxidative damage pathway.