Elevated Serum IgG4 Research Articles

Primary sclerosing cholangitis with moderately elevated serum-IgG4 - characterization and outcome of a distinct variant phenotype.

Immunoglobulin G4-associated cholangitis (IAC) is characterized by distinctly elevated immunoglobulin G4 in serum (sIgG4) and responds well to corticosteroid therapy. Primary Sclerosing Cholangitis (PSC) is a progressive liver disease without causal treatment options usually not responding to immunosuppression. Increased serum levels of sIgG4 in patients with PSC, that do not meet criteria of IAC, have been reported in 10%-25%. Therefore, we aimed to characterize this subgroup of patients in a retrospective, multicenter study. sIgG4 values of 289 patients with PSC from three German university hospitals were analysed. Patients with elevated sIgG4 levels were identified and further characterized by clinical and biochemical parameters and by cholangiographic presentation. Clinical endpoints, death and liver transplantation were compared between groups. Parameters associated with outcome were identified with Cox regression analysis. 14.5% of patients with PSC showed increased sIgG4 levels (PSC-IgG4), presented with significantly higher (P<.02) albumin, aspartate-aminotransferase, bilirubin and alkaline phosphatase and had a significant lower prevalence of a concomitant autoimmune hepatitis (P=.025). Cholangiogram obtained via ERC showed extrahepatic dominant strictures more often in the PSC-IgG4 subgroup (P=.047). The disease severity models Amsterdam-Oxford-Score (P=.018) and Mayo-Risk-Score (P=.025) predicted lower survival rates for the PSC-IgG4 subgroup. Transplant-free survival after first diagnosis of PSC was shorter in patients with elevated sIgG4 (11.6 vs 15.1years, P=.001). Patients with PSC and elevated sIgG4 should be considered as a distinct subgroup, characterized by different clinical and cholangiographical features and are associated with an inferior outcome.

Adenovirus-Vectored COVID-19 Vaccine-Induced Immune Thrombosis of Carotid Artery: A Case Report.

Venous thrombosis and thrombocytopenia after vaccination with the adenovirus-vectored COVID-19 vaccine ChAdOx1 nCov-19 (AstraZeneca) have been linked to serum antibodies against platelet factor 4 (PF4)-polyanion complexes. We here report vaccine-induced isolated carotid arterial thrombosis. Imaging and laboratory findings, treatment decisions, and outcome of this case are presented. Eight days after having received the first dose of ChAdOx1 nCov-19 vaccine, a 31-year-old man was admitted to our stroke unit with acute headache, aphasia, and hemiparesis. D-dimers were slightly elevated, but platelet count and fibrinogen level were normal. MRI-confirmed mainstem occlusion of middle cerebral artery resolved within 1 hour after the start of IV thrombolysis. A wall-adherent, nonoccluding thrombus in the ipsilateral carotid bulb was identified as the source of embolism. Cardiac or paradoxical (venous) embolism was excluded. Screening for the presence of heparin-induced thrombocytopenia-related antibodies was positive, and highly elevated serum IgG antibodies against PF4-polyanion complexes were subsequently proven. Treatment with aspirin and subcutaneous danaparoid, followed by phenprocoumon, led to thrombus shrinkage and dissolution within 19 days and favorable clinical outcome. Vaccine history is important in patients not only with venous but also with arterial thromboembolic events. Vaccine-induced immune thrombosis of brain-supplying arteries may well be handled.

Clinical characteristics of immunoglobulin G4-positive interstitial pneumonia.

This study suggests that IgG4+ IP with abundant IgG4+ cells and elevated serum IgG4 levels could be treated differently from IgG4-related respiratory disease due to potential differences in disease behaviour and response to corticosteroid therapy https://bit.ly/3dUo2cu

Renal Involvement in Retroperitoneal Fibrosis: Prevalence, Impact and Management Challenges.

Retroperitoneal fibrosis (RPF) is a rare disorder consisting of idiopathic and various secondary forms and characterized by chronic inflammatory infiltrates and marked fibrosis in the retroperitoneal space. In idiopathic RPF (IRPF), 35–60% of cases have been reported to be IgG4-related RPF, the retroperitoneal lesions of IgG4-related disease (IgG4-RD). IRPF can frequently lead to renal insufficiency mediated by urinary tract obstruction and hydronephrosis irrespective of being IgG4-related or not. Clinical pictures, laboratory and imaging findings, and location of the urinary tract obstruction are generally similar in IgG4-related and non-IgG4-related IRPF although multiple organ involvement and serum IgG4 elevation may be characteristic of the IgG4-related forms. Periaortic/periarterial lesions are the most frequent cause of renal insufficiency. Although the response to glucocorticoids is generally good, relapse does occur in a considerable proportion of patients, and may require an additional immunosuppressive agent and/or urological intervention in cases with multiple relapses or refractory obstructive uropathy. In general, the prognosis of patients with IRPF is good, but careful attention needs to be paid to chronic kidney disease as a major complication and rupture of the affected aorta/artery as a life-threatening one. Further studies are necessary to better understand the pathogenesis of the disease and to establish the optimal diagnostic and therapeutic strategies for it.

Immunoglobulin G4 (IgG4)‐related autoimmune hepatitis and IgG4‐hepatopathy: A histopathological and clinical perspective

AbstractImmunoglobulin G4 (IgG4)‐related disease (IgG4‐RD) is a chronic inflammatory disease that simultaneously or consecutively involves multiple organs of the body. It is characterized by elevated serum IgG4 levels and massive infiltration of IgG4+ plasma cells in the damaged tissues. IgG4‐related autoimmune hepatitis (IgG4‐AIH) and IgG4‐hepatopathy are relatively new entities that have been proposed as a phenotype of IgG4‐RD in the liver. Immunoglobulin G4‐AIH is defined as a disorder with serological, histopathological, and clinical features of both IgG4‐RD and AIH, simultaneously satisfying the diagnostic criteria of both classical AIH and IgG4‐RD. Although there are several case reports and studies of IgG4‐AIH among the published works, no consensus regarding the histopathological characteristics of IgG4‐AIH has been established, and its clinical implications remain obscure. Immunoglobulin G4‐hepatopathy is defined as a comorbidity of IgG4‐RD in the liver, and patients not meeting the diagnostic criteria of classical AIH could be diagnosed with IgG4‐hepatopathy. Numerous issues regarding these diseases, especially their epidemiology, histopathological and clinical characteristics, and treatment response to corticosteroids, remain unsolved, and need to be determined to establish the disease concepts of IgG4‐AIH and IgG4‐hepathopathy.

Immunoglobulin G4-Related Disease: What an Allergist Should Know.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory disorder that begins in 1 or more organs as inflammatory tumors that progress toward fibrosis. It is often accompanied by elevated serum IgG4. IgG4-RD was first described in 2003 as a new concept encompassing a number of immunoallergic diseases that had previously been considered unrelated. IgG4-RD mainly affects middleaged and older men. It consists of upregulation and expansion of CD4+ cytotoxic T lymphocytes, oligoclonal plasmablasts, and other inflammatory cells that infiltrate affected tissues and induce inflammation, organ dysfunction, and fibrosis. Symptoms depend on the location, severity, and extent of the disease. Virtually any organ can be affected, including the pancreas, salivary glands, lacrimal glands, thyroid gland, retro-orbital tissue, lymph nodes, retroperitoneum, mediastinum, lung, kidney, aorta, serosal surfaces, and meninges. Patients with widespread disease may present general symptoms. At least 30%-40% of patients are atopic or display atopic traits such as eosinophilia and elevated serum IgE levels. Additional laboratory features include increased serum IgG4 concentrations, increased blood IgG4-plasmablasts, hypergammaglobulinemia, and hypocomplementemia. Diagnosis of IgG4-RD is based on a clinicopathological correlation. Lymphoplasmacytic infiltrate with abundant IgG4-positive plasma cells, storiform-type fibrosis, obliterative phlebitis, and tissue eosinophilia are the pathological hallmarks. Therapy for IgG4-RD is based primarily on corticosteroids but may include additional immunomodulatory drugs and monoclonal antibodies such as rituximab. In individuals with allergic features, IgG4-RD should be suspected when a history of unexplained swelling is observed in 1 or more organs, particularly if they respond to corticosteroids and the patients are men in the sixth decade of life and beyond.

Idiopathic retroperitoneal fibrosis: clinical features, treatment modalities, relapse rate in Greek patients and a review of the literature.

Retroperitoneal fibrosis (RPF) is mostly idiopathic (iRPF); however, it can be secondary to drugs, malignancies, infections, or, as recently recognised, can be part of the IgG4-related diseases. The aim of our study was i) to describe the presenting clinical/laboratory/imaging features and treatment modalities used in patients with iRPF and ii) to evaluate factors potentially associated with disease relapse. The medical records of patients diagnosed with iRPF and followed in four tertiary medical units in Athens, Greece from 2000 to 2018 were retrospectively evaluated. Sixty-seven patients with iRPF were included in the study. Seventy-three per cent were males, with a mean age at diagnosis 56.0±9.2 years. Low-back pain (63%) and constitutional symptoms (57%) were the commonest presenting symptoms. Elevated acute-phase reactants (78%), anaemia (43%) and impaired renal function (41%) were the most common laboratory findings. Serum IgG4 at diagnosis was evaluated in 36/67 patients and 36% of them had elevated levels (mean 297.7±166.3mg/dL). Diagnosis was mainly based on abdominal CT and/or MRI. Clinical/laboratory/radiological presentation did not differ between patients with elevated and normal serum IgG4 levels. Steroids were used as first-line treatment in 98%. Relapse occurred in 28.6% after a mean of 43.1±31.8 months. Relapse did not associate to initial clinical/imaging findings or to any treatment used, however patients with increased serum IgG4 had a significantly higher relapse rate (75% vs. 25%, p=0.005). Relapse occurred in one-fifth of patients independently of the initial clinical/radiographic presentation or treatment used. iRPF patients with baseline elevated serum IgG4 levels have a higher relapse rate.

IgG4 as a Biomarker in Graves' Orbitopathy.

Immunoglobulin G4-related disease (IgG4-RD) is a chronic inflammatory disorder associated with fibrosis and abundant tissue lymphoplasmacytic infiltrations. It typically affects the pancreas, the salivary glands, and the retroperitoneal space. However, it might also involve multiple other organs, including the orbit and the thyroid. Recent studies have suggested that IgG4 plays a role in the pathophysiology of autoimmune thyroid diseases. This ultimately led to the establishment of new clinical entities called IgG4-related thyroid disease and thyroid disease with an elevation of IgG4. The aim of this paper is to describe the pathophysiological, histopathological, and clinical features of Graves' Disease (GD) and Graves' Orbitopathy (GO) with elevated IgG4 levels. Multiple studies have demonstrated higher IgG4 serum concentrations in GD patients than in healthy euthyroid controls. Depending on the studied population, elevated serum IgG4 levels occur in 6.4-23% (average: 10.3%) of all patients with GD, 8.3-37.5% (average: 17.6%) of patients with GO, and 0-9.8% (average: 5.4%) of patients with GD without GO, while GO patients comprise 37.5-100% (average: 65.8%) of all GD patients with elevated IgG4 levels. Characteristic features of GD with elevated IgG4 levels include lower echogenicity of the thyroid gland on ultrasound examination, peripheral blood eosinophilia, higher prevalence of orbitopathy, and better response to antithyroid drugs with a tendency to develop hypothyroidism when compared to patients with GD and normal levels of IgG4. Typical signs of GO accompanied by increased concentration of IgG4 include younger age at diagnosis, and more severe course of the disease with a higher Clinical Activity Score (CAS).. We strongly recommend considering the diagnosis of GO with elevated IgG4 in patients with an established diagnosis of GD, elevated serum IgG4 levels, and clinical features of ophthalmic disease overlapping with those of IgG4-related orbital disease.

Increased Expression of Activation-Induced Cytidine Deaminase in Sinus Mucosa from IgG4-Related Disease Patients with Comorbid Chronic Rhinosinusitis

Objective: IgG4-related disease (IgG4-RD) is a systemic condition characterized by an elevated serum IgG4 level, localized infiltration of IgG4-positive plasma cells, and lesions in various organs. IgG4-RD also shows high rates of complication with allergic diseases and is often accompanied by elevated serum IgE levels. Reports in recent years have also shown high rates of complication with chronic rhinosinusitis (CRS) and its characteristic nasal manifestations. Accordingly, we speculate that there may be a distinct form of CRS that, as an IgG4-RD, differs from other CRS. Here, we investigated whether the elevated levels of factors that are thought to be important in the pathogenesis of IgG4-RD are also seen in the sinus mucosa of IgG4-RD-associated CRS patients. Methods: Ethmoid sinus mucosa specimens from 9 IgG4-RD (6 Mikulicz disease and 3 Küttner’s tumor) patients with elevated serum IgG4 and IgE and from 22 control CRS patients were examined immunohistochemically for Treg cytokines (IL-10 and TGF-β), activation-induced cytidine deaminase (AID), and immunocompetent cells. The 22 control CRS patients were divided into 3 subgroups based on the serological findings for IgG4 and IgE. Quantitative real-time PCR was performed to examine the expression of AID. Results: The ethmoid sinus mucosa from patients with IgG4-RD-associated CRS showed, in comparison with the 3 CRS control subgroups, significantly elevated AID production. Their mucosa also showed significantly increased infiltration of CD-20-positive immunocompetent cells compared with the controls. On the other hand, immunohistochemical examination found no significant differences in the number of IL-10- or TGF-β-positive cells. Conclusion: Ethmoid sinus mucosa from IgG4-RD-associated CRS patients showed clearly increased AID production, suggesting AID involvement in class-switching to IgG4 in those local sites. This implies the existence of a distinct form of CRS that is an IgG4-RD.

AB0125 CLINICAL CHARACTERISTICS OF RHEUMATOID ARTHRITIS PATIENTS WITH IGG4-RELATED SYNOVITIS

Background:Elevated serum IgG4 (sIgG4) and IgG4+ plasma cell tissue infiltration are outstanding features of IgG4-related disease (IgG4-RD). However, elevated IgG4 is not specific for IgG4-RD. Our previous study reported elevated sIgG4 in 46% of rheumatoid arthritis (RA) patients (Mediators Inflamm 2014). Whether synovium from RA patients show similar characteristics of IgG4-RD and how about the clinical characteristics of RA patients with IgG4-related synovitis have not been reported yet.Objectives:To explore the serum and synovial IgG4 level and their correlation with disease indicators in RA.Methods:Active RA patients who underwent needle synovial biopsy with qualified synovium tissue were recruited. Demographic and clinical data were collected simultaneously. Synovium tissue were stained with H&amp;E for Krenn synovitis score and immunohistochemistry for positive cell densities of CD20, CD38, IgG and IgG4. Serum IgG4 level was detected by immunonephelometry.Results:Among 96 RA patients recruited, 74 (77.1%) were female, the median age was 55.0 (46.0~61.0) years, disease duration was 42.0 (12.0~120.0) months and SDAI was 31.2 (22.1~42.8).The median sIgG4 was 1.38 (0.86~2.42) g/L and 49(51.0%) patients had elevated sIgG4. Compared with those with normal sIgG4, RA patients with elevated sIgG4 had significantly higher levels of PrGA [7 (5~8) vs. 6 (4~7)], ESR [90 (64~116) mm/h vs. 61 (38~75) mm/h], CRP [46.20 (17.20~74.20) mg/L vs. 18.90 (9.46~49.20) mg/L], DAS28-ESR [6.3 (5.6~7.4) vs. 5.7 (4.7~6.4)], SDAI [34.2 (25.3~48.8) vs. 27.8 (18.9~35.9)] and HAQ-DI [1.70 (0.61~2.28) vs. 0.88 (0.40~1.75), all P&lt;0.05]. Meanwhile, they also showed significantly higher synovial counts of CD38+ plasma cells [1240(559~2290) /mm2 vs. 1020(354~1777) /mm2], IgG4+ plasma cells [106 (39~249) /mm2 vs. 68 (3~123) /mm2], and higher ratio of IgG4+/IgG+ plasma cells [26.3 (15.5~38.0) % vs. 15.2 (0.9~24.7) %, all P&lt;0.05].The median IgG4+ plasma cells count was 83 (10~192) /mm2 and median ratio of IgG4+/IgG+ plasma cells was 19.1 (8.4~31.5)%. Both of them correlated positively with ESR, CRP and sIgG4 (r=0.216~0.394, all P&lt;0.05). There were 46 (47.9%) patients with IgG4+ plasma cells &gt;10/HPF, who had significant higher ESR [86 (50~109) mm/h vs. 65 (40~84) mm/h] and CRP [43.35 (16.93~77.85) mg/L vs. 26.15 (9.54~52.53) mg/L, both P&lt;0.05] than those with IgG4+ plasma cells ≤10/HPF. There were 13 (13.5%) patients with the ratio of IgG4+/IgG+ plasma cells &gt;40%, and 11 (11.5%) patients with both IgG4+ plasma cells &gt;10/HPF and IgG4+/IgG+ plasma cells ratio &gt;40% (IgG4-related synovitis). RA patients with IgG4-related synovitis had significant higher ESR than the others [106 (53~125) mm/h vs. 69 (41~91) mm/h, P&lt;0.05].There were 10 (10.4%) patients showing elevated sIgG4 and IgG4-related synovitis. Four patients completed 1-year follow-up and all of them achieved remission at 6th month (SDAI≤3.3, Figure 1). Only one patient had radiographic progression at 12th month.Figure 1.Dynamic disease activity of 4 RA patients with elevated sIgG4 and IgG4-related synovitis during 1-year follow-up.Conclusion:IgG4-related synovitis can be found in RA patients. Their clinical significance in disease characteristics and outcomes are worth further study.Acknowledgements:This work was supported by National Natural Science Foundation of China (no. 81971527, 81801606 and 81801605), Guangdong Natural Science Foundation (no. 2018A030313541 and 2018A030313690), Guangdong Medical Scientific Research Foundation (no. A2018062), Guangdong Basic and Applied Basic Research Foundation (no. 2019A1515011928 and 2020A1515110061), and Science and Technology Program of Guangzhou (no. 201904010088).Disclosure of Interests:None declared

AB0853 IGG4-RELATED DISEASE CAUSING OCULAR NERVE PALSIES AND ORBITAL APEX SYNDROME: CASE REPORT AND LITERATURE REVIEW

Background:IgG4-Related Disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory condition. The epidemiology is not well defined: it usually affects adults from middle-age onwards, predominantly male. Both B and T-cells are central in IgG4-RD pathogenesis, as demonstrated by the efficacy of B-cell depletion therapy.IgG4-RD can affect multiple organs including the central and peripheral nervous system, producing a constellation of clinical symptoms and signs, depending on the organ structures involved.IgG4-related orbital disease is relatively rare can implicate all extra-ocular muscles, structures emerging from the Orbital apex, optic canal, or superior and inferior orbital fissure. Depending on the structures involved, it can produce different or sometimes subtle clinical presentations, posing diagnostic challenge. There were case reports of IgG4-related ophthalmic disease misdiagnosed as intraocular tumour.Objectives:IgG4-RD is increasingly recognised as an entity affecting the head and neck region. However, it rarely involves skull base and presents with orbital apex syndrome. In this current case report, we describe an interesting case of IgG-related orbital disease presenting with ocular nerve palsies and orbital apex syndrome.Methods:Case report.Results:A 36-year-old gentleman with cocaine and alcohol misuse presented with a 2-month history of left sided headache, diplopia, recurrent ear infections, otalgia and hearing loss. Initial imaging suggested left otomastoiditis and intravenous antibiotics were commenced. Contralateral partial third nerve palsy with pupil sparing was elicited. 2 months later, there was worsening right eye ptosis, proptosis, right relative afferent pupillary defect, reduced visual acuity and colour vision as well as a near-complete ophthalmoplegia. Subsequent imaging showed worsening soft tissue swelling centred on the upper left parapharyngeal and masticator space, with multiple perineural enhancement and lateral extension to right orbital apex and orbital fissures. Blood tests only revealed raised IgG4 subclass. Infectious aetiology was excluded. Left nasal mass biopsy performed showed no fungal organism or malignancy. There were lymphoplasmacytic proliferation but no storiform fibrosis or obliterative phlebitis. IgG4 immunostaining on two assessable fields revealed 22 and 17 positive plasma cells respectively, and an IgG4: IgG ratio of &lt;10%, and 50% in the other. Significant improvement was seen clinically and radiologically with antibiotics and a tapering regime of oral Prednisolone. Patient was commenced on Azathioprine as long term immunosuppression.Conclusion:A high degree of clinical suspicion is necessary to diagnose IgG4-RD when presenting with orbital apex syndrome and ocular nerve palsies,IgG4-RD can mimic mastoiditis of infectious aetiology. Other differentials may include cocaine-induced midline destructive lesions and granulomatosis with polyangiitis. The diagnosis can be supported by elevated serum IgG, elevated IgG index and pathognomonic histopathological findings. . The diagnosis of IgG4-related orbital disease should be deliberated on by a multidisciplinary group, with every effort being made to exclude an infectious aetiology, before embarking on immunosuppressive therapy.Primary treatment is with steroids. However, immunotherapy using azathioprine can be utilised in recurrent disease or patients with steroid intolerance.

IgG4-related disease in pediatric patients: a single-center experience.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic, immune-mediated, and fibroinflammatory disease that can affect almost any organ system. We aimed to present our single-center experience of pediatric patients with IgG4-RD, a rare disease in children. Pediatric patients diagnosed with IgG4-RD at the Hacettepe University between June 2014 and September 2020 were evaluated retrospectively. Patients with definite, probable, or possible diagnosis of IgG4-RD were included. A total of eight patients with a median age of 13.4 (IQR 9.5-15.0) years were included in the study. Clinical presentations were IgG4-related ophthalmic disease in six patients, IgG4-related lymphadenopathy in one patient, and IgG4-related sialadenitis and lymphadenopathy of several lymph nodes accompanied by pancreatitis, ulcerative colitis, and pulmonary manifestations in one patient. Elevated serum IgG4 was detected in three of eight patients (37.5%). The main histopathological feature was fibrosis and lymphoplasmacytic infiltrates. Corticosteroids were used as first-line treatment in almost all patients with or without steroid-sparing agents. Azathioprine, methotrexate and rituximab were used as steroid-sparing agents. Relapse occurred in two of seven patients. Radiotherapy was used as the last resort in one patient with severe orbital disease. IgG4 RD mainly presents with orbital manifestations in pediatric population but has wide phenotypic clinical variability. Although rare, early recognition and treatment are essential for a better outcome in these patients.

Association of Serum Immunoglobulins Levels With Specific Disease Phenotypes of Crohn's Disease: A Multicenter Analysis in China.

Background and Aim: Serum immunoglobulins were reported to be associated with clinical characteristics of inflammatory bowel disease. However, whether a difference exists in the serum immunoglobulins levels in patients with Crohn's disease (CD) with different disease location and behavior phenotypes remains unclear. Therefore, this study aimed to explore the associations of serum immunoglobulins levels with specific CD phenotypes.Methods: Patients with CD having recorded serum immunoglobulins levels were recruited through multicenter collaborative efforts. The associations between serum immunoglobulins levels and distinct phenotypes of CD were evaluated using multiple logistic regression models.Results: A total of 608 patients with CD were included in the study. Elevated (above the upper limit of normal) serum immunoglobulin G (IgG), IgA, IgM, and IgG4 were identified in 24.5, 17.4, 2.1, and 8.2% of patients, respectively. Elevated serum IgG4 levels negatively correlated with complicated disease behavior [odds ratio (OR) 0.49, 95% confidence interval (CI) 0.26–0.92]. Elevated serum IgG was linked to isolated ileal disease with an OR of 0.37 (95% CI 0.23–0.61). The ORs of isolated ileal disease progressively reduced across increasing quartiles of IgG (P for trend < 0.001). The adjusted ORs of isolated ileal disease for increasing quartiles of IgM were 1.82 (1.07–3.1), 1.92 (1.14–3.24), 1.17 (0.69–1.98), and 1 (P for trend = 0.008). Besides, serum IgA and IgG levels significantly correlated with several disease activity indices.Conclusions: These results suggested that certain serum immunoglobulins were associated with specific disease phenotypes of CD. Further investigations to account for the associations are warranted.

Clinical characteristics of igG4-related disease in the United Arab Emirates: A retrospective single-center study

Background: Demographic and clinical data of IgG4-related disease affecting solely the native population of the UAE, known as Emiratis, does not exist in the literature. Aim: To explore the demographic and clinical characteristics of IgG4-related disease in a well-defined population of Emirati patients attending Cleveland Clinic Abu Dhabi, a large tertiary center in the Middle East. Patients and Methods: The data presented is part of a retrospective cohort study, in which 15 Emirati patients with IgG4-related disease (IgG4-RD) were evaluated over 5 years from April 2015 to September 2020 at the rheumatology outpatient clinic at Cleveland Clinic Abu Dhabi. The demographic and clinical data were recorded. Descriptive statistics of the variables were applied. Results: Fifteen Emirati patients with an established diagnosis of IgG4-RD were assessed. There was a male predominance (53%) with a median age at the time of diagnosis of 47 ± 11.2 years. A 6-year lag period was noted from the initial presentation until a diagnosis of IgG4-RD was established. The most frequent comorbidities observed were hematological conditions (63%), hypertension (47%), diabetes mellitus (40%), and gastroesophageal reflux disease (40%). An elevated serum IgG4 was observed in the majority of patients at the initial presentation. Rheumatoid factor was detected in 13% and low titer of immunofluorescence antinuclear antibody in 7%. 86% of patients had a tissue biopsy with marked lymphocytic and plasmacytic infiltration being the most reported finding in 86%. Methotrexate, azathioprine, and rituximab were the most frequently prescribed disease-modifying agents. Conclusion: We report the first comprehensive analysis on a small cohort of Emirati patients with IgG4-RD. We describe disease features unique to UAE patients and demonstrate that IgG4-RD has a significant disease burden. Our results underscore the need for the IgG4-RD UAE-wide national registry to improve the quality of care of these patients.

Cut-off values of serum IgG4 among three reagents, including a novel IgG4 reagent: a multicenter study

Elevated serum IgG4 is a useful marker of IgG4-related disease (IgG4-RD) activity. However, there is no uniformity in the cut-off values of IgG4 among the various reagents. The aim of this study was to compare the measured and cut-off values of IgG4 assessed using three different reagents. This study enrolled 466 IgG4-RD and non-IgG4-RD patients who required measurement of serum IgG4 levels to diagnose or treat IgG4-RD. Serum IgG4 was measured using three reagents: N-assay LA IgG4 Nittobo (Nittobo), BS-NIA IgG4 (TBS), and N Latex IgG4 (Siemens). The values obtained using the three reagents were compared, and cut-off values were calculated for each. Although there was good correlation among the results with the three reagents, the measured and cut-off values were all different. The Nittobo values were 1.4 times the TBS values and the TBS values were almost half those of the Siemens values. ROC curve analysis showed cut-off values for the Nittobo, TBS, and Siemens reagents of 1.42, 1.31, and 2.38 g/L, respectively. The measured and cut-off values of serum IgG4 vary depending on the reagents used for the assay, although there is good correlation among the values measured by the three reagents.

Isolated middle mediastinal mass associated with immunoglobulin G4-related disease

BackgroundImmunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder predominantly occurring in middle-aged to elderly male patients characterized by multi-organ fibrosis, specific pathological findings of storiform fibrosis with IgG4-positive plasma cell infiltration, and elevated serum IgG4 level. We herein report a rare presentation of IgG4-RD forming an isolated mass in the middle mediastinum mimicking a mediastinal tumor and discuss the clinical significance of mediastinal IgG4-RD.Case presentationAn 82-year-old male patient without any symptom was referred due to left middle mediastinal mass (3.8 × 2.4 cm). Because of suspected lymphoma, Castleman’s disease, and lymphangitis due to tuberculosis, we performed a thoracoscopic resection for diagnosis and treatment. The mass was yellowish white with well-encapsulated, and storiform fibrosis with plasma cell infiltration, and obliterative phlebitis were observed microscopically. Additional immunohistochemical stain revealed IgG4-RD. Other radiological findings and serological results did not show evidence of other organs being affected from IgG4-RD nor autoimmune diseases. He is now followed at outpatient clinic without additional treatment for over a year, and an enhanced computed tomography does not show any recurrence.ConclusionIt was a rare presentation of IgG4-RD forming isolated middle mediastinal mass, which suggests that we might suspect IgG4-RD for undetermined mediastinal mass in case of middle to elderly male patient.

A case of episodic angioedema with eosinophilia in an elderly woman with primary biliary cholangitis

We present the case of a 56-year-old woman diagnosed with primary biliary cholangitis (PBC). She has continuously taken 600mg/day of ursodeoxycholic acid. Edema of the lower limbs manifested on July 20, 20XX; after 2weeks, she manifested rapid weight gain and nettle rash on the limbs and trunk. She was admitted to our hospital on August 22. She had marked eosinophilia, hypoalbuminemia, anemia, non-pitting lower limbs edema, and nettle rash of the limbs and the trunk. We ruled out other diseases that may have caused the edema and suspected her with episodic angioedema with eosinophilia (EAE). The peripheral blood eosinophil count rapidly decreased after the administration of 30mg prednisolone. The edema and nettle rash improved on the 7th day of admission, and the hypoalbuminemia and anemia improved on the 14th day. Prednisolone was tapered and discontinued, and there was no relapse of edema. We revised our diagnosis to non-recurrent EAE. She was diagnosed with asymptomatic PBC; therefore, anemia and hypoalbuminemia were considered not PBC but chronic inflammation and decrease in appetite. In this case, elevation of serum IgG4 was observed at onset and at remission. This suggests that IgG4 may be involved in the development of EAE in patients with chronic liver disease.

The pronounced lung lesions developing in LATY136F knock-in mice mimic human IgG4-related lung disease.

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a novel clinical disease entity characterized by an elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4-positive plasma cells. Pathological changes are most frequently seen in the pancreas, lacrimal glands, and salivary glands, but pathological changes in the lung also exist. Linker for activation of T cell (LAT)Y136F knock-in mice show Th2-dominant immunoreactions with elevated serum IgG1 levels, corresponding to human IgG4. We have reported that LATY136F knock-in mice display several characteristic features of IgG4-RD and concluded that they constitute an appropriate model of human IgG4-RD in salivary glands, pancreas, and kidney lesions. The aim of this study is to evaluate whether lung lesions in LATY136F knock-in mice can be a model of IgG4-related lung disease. Lung tissue samples from LATY136F knock-in mice (LAT) and wild-type mice (WT) were immunostained for IgG1 and obtained for pathological evaluation, and cell fractions and cytokine levels in broncho-alveolar lavage fluid (BALF) were analyzed. In the LAT group, IgG1-positive inflammatory cells increased starting at 4 weeks of age and peaked at 10 weeks of age. The total cell count and percentage of lymphocytes increased significantly in BALF in the LAT group compared to the WT group. In BALF, Th2-dominant cytokines and transforming growth factor-β were also increased. In the LAT group, marked inflammation around broncho-vascular bundles peaked at 10 weeks of age. After 10 weeks, fibrosis around broncho-vascular bundles and bronchiectasis were observed in LATY136F knock-in mice but not WT mice. LATY136F knock-in mice constitute an appropriate model of lung lesions in IgG4-RD.

Clinical characteristics of immunoglobulin IgG4-related sclerosing cholangitis: Comparison of cases with and without autoimmune pancreatitis in a large cohort

BackgroundThe clinical characteristics of IgG4-related sclerosing cholangitis (IgG4-SC) especially without autoimmune pancreatitis (AIP) have not been investigated in a large cohort. AimsTo clarify the clinical characteristics of IgG4-SC and IgG4-SC without AIP. MethodsWe retrospectively reviewed imaging, serology, other organ involvement (OOI) and histology of 872 patients with IgG4-SC who participated in a Japanese nationwide survey in 2019, and compared these items between IgG4-SC with and without AIP. ResultsAIP was present in 83.7% (730/872) of IgG4-SC. In IgG4-SC, bile duct wall thickening was observed on ultrasound (528/650; 81.2%), computed tomography (375/525; 71.4%) and magnetic resonance imaging or cholangiopancreatography (290/440; 65.9%). An elevated serum IgG4 level (≥ 135 mg/dL) was found in 88.0% (322/366). IgG4-related OOI other than AIP was observed in 25.2% (211/836). The proportion of females was significantly higher in IgG4-SC without AIP (28.9% vs. 20.1%; p = 0.025). Hilar stricture was the most common cholangiographic type in IgG4-SC without AIP (39/107; 36.4%).There were no significant differences between IgG4-SC with and without AIP in the rates of bile duct wall thickening, elevated serum IgG4 level, or IgG4-related OOI. ConclusionsThe clinical characteristics of IgG4-SC was similar between IgG4-SC with and without AIP in a large cohort.

IgG4-related disease

IgG4-related disease (ER-IgG4) is a recognised systemic disease. It was described after patients diagnosed with autoimmune pancreatitis showed signs of extra-pancreatic disease. The clinical manifestation of these patients is subacute and is manifested by the appearance of pseudotumoral lesions, or inflammatory or fibrous tumours. Sometimes it can be serious as in the case of patients with cholangitis or large vessel vasculitis. Diagnostic criteria include, among others, serum IgG4 elevation and/or histological parameters. The 18F-FDG-PET/CT is useful in the initial diagnosis, biopsy guidance as well as in the assessment of response to therapy. It usually responds to steroid therapy.