Immunoglobulin G4 Research Articles

Anti-MET Antibody Therapies in Non-Small-Cell Lung Cancer: Current Progress and Future Directions.

Background/Objectives: Non-small-cell lung cancer (NSCLC) remains a leading cause of cancer mortality globally, though advances in targeted therapies have improved treatment outcomes. The mesenchymal-epithelial transition (MET) gene plays a significant role in NSCLC, often through protein overexpression, exon 14 skipping mutations, and gene amplification, many of which arise as resistance mechanisms to other oncogenic drivers like epidermal growth factor receptor (EGFR) mutations. This review examines the development and clinical efficacy of anti-MET antibody therapies. Methods: A comprehensive literature search was conducted using major medical databases looking at key relevant studies on anti-MET antibody studies. Both authors reviewed the literature, assessed study quality, and interpreted the results from each study. Results: Amivantamab, a bispecific EGFR/MET antibody was approved to treat EGFR exon 20 insertion and now has recently been extended to target classical EGFR mutations with progression on osimertinib. Other important anti-MET targeted therapies in development include antibody drug conjugates such as telisotuzumab vedotin, REGN5093-M114, and AZD9592 and emibetuzumab, which is a humanized immunoglobulin G4 monoclonal bivalent MET antibody. Conclusions: MET plays a significant role in NSCLC and amivantamab along with other anti-MET targeted therapies play a role in directly targeting MET and addressing acquired resistance to oncogenic drivers. Future research should focus on developing novel MET antibody drugs and exploring new therapeutic combinations to enhance treatment efficacy and overcome resistance in NSCLC. Refining biomarker-driven approaches to ensure precise patient selection is also critical to optimizing treatment outcomes.

7229 A Rare Case of Igg4 Hypophysitis Presenting as Hypogonadotropic Hypogonadism

Abstract Disclosure: C. Dimech: None. G. Jaiswal: None. Hypophysitis is a rare pituitary disorder including a broad range of inflammatory processes which affect the pituitary gland and infundibulum. Previously reported as 1 per 9 million individuals, the true incidence of hypophysitis per year is largely unknown due to the increase of novel etiologies such as immunoglobulin G4 (IgG4)- related disease. IgG4-related hypophysitis (IgG4-RH) was first clinically described in 2004 and later biopsy proven in 2007. The main clinical features are elevated serum IgG4 level and IgG4-positive lymphocyte infiltration of tissues on histopathology. IgG4-RH is reported to account for 1.3% of primary hypophysitis with 3.2:1 incidence ratio of men to women, in the 6th decade of life. Here we present a case of a 68-year-old Caucasian male who presented for evaluation of hypogonadotropic hypogonadism. As fasting morning testosterone levels were significantly low, MRI pituitary was completed which revealed a homogenously enhancing pituitary gland with thickened, nodular enhancement of the pituitary infundibulum. Subsequent lab work-up revealed normal function of remaining anterior pituitary without evidence of central vasopressin deficiency. Evaluation of underlying etiologies was unremarkable except for significantly elevated IgG4 levels (472mg/dL). Based on the significantly elevated IgG-4 levels (>135 mg/dl) and the radiographic findings of the pituitary infundibulum, the diagnosis of possible IgG4-RH was made. The patient was initiated on treatment with rituximab and glucocorticoid therapy with prednisone. Following 3 months of medical therapy, MRI pituitary showed resolution of stalk inflammation, confirming diagnosis of IgG4- RH. Presentation: 6/1/2024

Humoral signatures of Caspr2-antibody spectrum disorder track with clinical phenotypes and outcomes.

Immunoglobulin (Ig) G4 auto-antibodies (Abs) against contactin-associated protein-like 2 (Caspr2), a transmembrane cell adhesion protein expressed in the central and peripheral nervous system, are found in patients with a broad spectrum of neurological symptoms. While the adoptive transfer of Caspr2-specific IgG induces brain pathology in susceptible rodents, the mechanisms by which Caspr2-Abs mediate neuronal dysfunction and translate into clinical syndromes are incompletely understood. We use a systems-level approach combined with high-dimensional characterization of Ab-associated immune features to deeply profile humoral biosignatures in patients with Caspr2-Ab-associated neurological syndromes. We identify two signatures strongly associated with two major clinical phenotypes, limbic encephalitis (LE) and predominant peripheral nerve hyperexcitability without LE (non-LE). Caspr2-IgG Fc-driven pro-inflammatory features, characterized by increased binding affinities for activating Fcγ receptors (FcγRs) and C1q, along with a higher prevalence of IgG1-class Abs, in addition to IgG4, are strongly associated with LE. Both the occurrence of Caspr2-specific IgG1 and higher serum levels of interleukin (IL)-6 and IL-15, along with increased concentrations of biomarkers reflecting neuronal damage and glial cell activation, are associated with poorer clinical outcomes at 1-year follow-up. The presence of IgG1 isotypes and Fc-mediated effector functions control the pathogenicity of Caspr2-specific Abs to induce LE. Biologics targeting FcR function might potentially restrain Caspr2-Ab-induced pathology and improve clinical outcomes. This study was funded by a German-French joint research program supported by the German Research Foundation (DFG) and the Agence Nationale de la Recherche (ANR) and by the Interdisciplinary Centre for Clinical Research (IZKF) Münster.

A rare pathology that mimics lung cancer: IgG4-related vasculitis.

Immunoglobulin-G4 (IgG4)-related disease is essentially a fibro-inflammatory disease that can affect any organ simultaneously or at different times. The disease usually presents with organ growth that mimics a tumour and can affect the lacrimal glands, major salivary glands, pancreas, bile ducts, retroperitoneal area, lungs, kidneys, aorta, meninges and thyroid gland. The immunopathogenesis behind this new disease has not yet been elucidated. Histopathological distinguishing features of the disease include dense lymphoplasmocytic infiltrates dominated by IgG4 positive plasma cells, storiform fibrosis and obliterative phlebitis. The likelihood of developing with immunoglobulin G4 (IgG4-RD) is a recently identified rare systemic fibroinflammatory disease with an estimated incidence of less than 1 in 100,000 people worldwide. We present our case, which was diagnosed with IGG4-related vasculitis by lung fine needle aspiration biopsy, which is very rare in the literature.

Nivolumab and Cabozantinib Immunotherapy Induced Thyroid Dysfunction Detected on 18 F-FDG PET/CT in Renal Cell Carcinoma.

Targeted immunotherapy became the most advanced approach for cancer treatment. Programmed death-1 (PD-1) expressed on activated T cells can reverse immune suppression and cause T-cell activation. Nivolumab, a PD-1 immune checkpoint inhibitor antibody that is a fully human immunoglobulin G4, blocks PD-1 and promotes antitumor immunity. Cabozantinib (tyrosine kinase inhibitor) inhibits the tyrosine kinase activity of vascular endothelial growth factor receptors 1, 2, and 3. As a result of enhancing immune response in normal tissues, immune-related adverse events can occur. Thyroid dysfunction is a common form of immune-related adverse event and seen on 18 F-FDG PET/CT scans post therapy.

Steroid-resistant immunoglobulin G4-related coronary arteritis: A case report

Abstract Background Immunoglobulin G4 (IgG4)-related diseases are systemic fibroinflammatory disease characterized by extensive infiltration of IgG4-positive plasma cells in the affected tissue(s), with high plasma levels of IgG4. However, coronary involvement is rare. Case Summary A 70-year-old man was diagnosed with IgG4-related coronary arteritis, pancreatitis, and cholangitis during full-body contrast computed tomography (CT) examination prior to surgery for an iliac artery aneurysm. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT showed increased uptake of 18F-FDG in the pancreas, extrahepatic bile ducts, and proximal right coronary artery (RCA). Despite the patient being asymptomatic, the RCA showed severe stenosis. The patient was administered a conservative treatment with prednisolone, 30 mg/day, gradually tapered to 5 mg/day, for 6 months. Two years later, contrast CT showed improvement of the pancreatic and bile duct lesions; however, the steroid therapy had not improved the coronary artery lesions, and gradual progression of the lesions was observed. Percutaneous coronary intervention was performed with a cutting balloon in the RCA, and good patency was maintained for 1 year after the procedure. Discussion Steroid therapy is the first-line treatment for IgG4-related diseases; however, there may be some refractory cases. The stenotic and aneurysmal type IgG4-related coronary arteritis are life-threatening; therefore, we performed revascularization using balloon angioplasty. Determining the optimal revascularization technique for drug-refractory cases requires further investigation.

Immunoglobulin G4 in primary Sjögren's syndrome and IgG4-related disease - connections and dissimilarities.

Primary Sjögren's syndrome (pSS) is an autoimmune disease, with B cell hyperactivation and autoantibody production as its immunological hallmarks. Although the distinction between immunoglobulin G4-related disease (IgG4-RD) and pSS, based on the presence or absence of certain autoantibodies, seems easy to make, possibility of elevated serum IgG4 concentration and often similar organ involvement may lead to a misdiagnosis. The increased serum concentration of IgG4 in IgG4-RD is not clearly linked to the pathogenesis of IgG-RD and it has been suggested that it may constitute just an epiphenomenon. The aim of this article is to discuss the presence of IgG4 in pSS and IgG4-RD and its potential significance for these two diseases.

Deep humoral profiling coupled to interpretable machine learning unveils diagnostic markers and pathophysiology of schistosomiasis.

Schistosomiasis, a highly prevalent parasitic disease, affects more than 200 million people worldwide. Current diagnostics based on parasite egg detection in stool detect infection only at a late stage, and current antibody-based tests cannot distinguish past from current infection. Here, we developed and used a multiplexed antibody profiling platform to obtain a comprehensive repertoire of antihelminth humoral profiles including isotype, subclass, Fc receptor (FcR) binding, and glycosylation profiles of antigen-specific antibodies. Using Essential Regression (ER) and SLIDE, interpretable machine learning methods, we identified latent factors (context-specific groups) that move beyond biomarkers and provide insights into the pathophysiology of different stages of schistosome infection. By comparing profiles of infected and healthy individuals, we identified modules with unique humoral signatures of active disease, including hallmark signatures of parasitic infection such as elevated immunoglobulin G4 (IgG4). However, we also captured previously uncharacterized humoral responses including elevated FcR binding and specific antibody glycoforms in patients with active infection, helping distinguish them from those without active infection but with equivalent antibody titers. This signature was validated in an independent cohort. Our approach also uncovered two distinct endotypes, nonpatent infection and prior infection, in those who were not actively infected. Higher amounts of IgG1 and FcR1/FcR3A binding were also found to be likely protective of the transition from nonpatent to active infection. Overall, we unveiled markers for antibody-based diagnostics and latent factors underlying the pathogenesis of schistosome infection. Our results suggest that selective antigen targeting could be useful in early detection, thus controlling infection severity.

Efficacy and Safety of Iparomlimab, an Anti-PD-1 Antibody, in Patients with Advanced Solid Tumors: A Phase 1c Study.

Iparomlimab (QL1604) is a humanized immunoglobulin G4 mAb against programmed cell death protein 1 (PD-1). Here, we report the preliminary efficacy, safety, pharmacokinetics, and immunogenicity of iparomlimab in patients with advanced solid tumors. In this open-label, phase 1c study, patients with advanced or metastatic solid tumors, either failed or had no standard therapies available, were enrolled and received intravenous iparomlimab at 3mg/kg once every 3weeks. The primary efficacy endpoint was the objective response rate (ORR) assessed by the investigator per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Between July 20, 2020, and September 6, 2021, 71 patients were enrolled and received at least one dose of iparomlimab. The ORR was 9.9% (7/71) and disease control rate was 36.6% (26/71). Median duration of response of all responders was 10.7months [95% confidence interval (CI), 1.4-not estimable]. Additionally, the median time to progression, progression-free survival, and overall survival were 1.4months (95% CI, 1.4-2.8), 1.4months (95% CI, 1.4-2.7), and 9.7months (95% CI, 7.2-15.3), respectively. A total of 52 (73.2%) patients experienced treatment-related adverse events (TRAEs) (grade≥3, 19.7%). The most common TRAE (≥10%) was anemia (18.3%). A total of 20 (28.2%) experienced immune-related adverse events (grade≥3, 7.0%). TRAEs leading to discontinuation of study drug occurred in 4 (5.6%) patients, including immune-mediated myocarditis (2 patients), Guillain-Barré syndrome (1 patient), and diarrhea (1 patient). Iparomlimab showed preliminary clinical activity and had a manageable safety profile in patients with advanced solid tumors. These results support further investigation of iparomlimab as monotherapy or in combination therapy in advanced solid tumors. ClinicalTrials.gov identifier, NCT05801094. Retrospectively registered in 2023-03-24.

Efficacy and safety of two fixed doses of ibalizumab plus optimized background regimen in treatment-experienced HIV-positive individuals.

Sustained viral suppression in patients with multidrug-resistant (MDR) human immunodeficiency virus (HIV) infection remains difficult; accordingly, agents targeting different steps in the HIV life cycle are needed. Ibalizumab, a humanized immunoglobulin G4 monoclonal antibody, is a cluster of differentiation (CD4)-directed post-attachment inhibitor. In this Phase IIb study, 113 individuals with MDR HIV-1 and limited treatment options were assigned an optimized background regimen (OBR) and randomized to either 800 mg ibalizumab every two weeks (q2wk; n=59) or 2,000 mg ibalizumab every four weeks (q4wk; n=54) up to Week 24. Viral loads (VL) below the detection limit were achieved in 44% and 28% of patients in the 800 mg q2wk and 2,000 mg q4wk groups, respectively, at Week 24. Mean (standard deviation) VL (log10 copies/mL) decreased from Baseline (4.6(0.8), 800 mg q2wk; 4.7(0.7), 2,000 mg q4wk) to Week 2, with the reduction maintained through Week 24 (2.9(1.5), 800 mg q2wk; 3.2(1.4), 2,000 mg q4wk). Baseline CD4+ counts were 80.5 and 54.0 cells/μL in the 800 mg q2wk and 2,000 mg q4wk groups, respectively. Mean CD4+ T-cell count was increased at Week 24 in both groups. No serious adverse events were related to ibalizumab. In heavily treatment-experienced patients with HIV (PWH) at a more advanced baseline disease severity, clinically significant response rates at Week 24 were achieved with ibalizumab plus OBR. Ibalizumab's unique mechanism of action and lack of cross-resistance to other antiretroviral agents make it an important component of combination treatment regimens for PWH with limited treatment options.

Factors related to elevated serum immunoglobulin G4 (IgG4) levels in a Japanese general population

BackgroundElevated serum immunoglobulin G4 (IgG4) concentrations are one of the characteristic findings in IgG4-related disease (IgG4-RD). This study investigated the frequency of elevated serum IgG4 levels and associated factors in a general Japanese population.MethodsSerum IgG4 concentrations were measured in 1,201 residents of Ishikawa prefecture who underwent general medical examinations. Factors associated with elevated serum IgG4 concentrations were assessed by logistic regression analysis. Participants with elevated serum IgG4 were subjected to secondary examinations.ResultsThe mean serum IgG4 concentration was 44 mg/dL, with 42 (3.5%) participants having elevated serum IgG4 levels. Age- and sex-adjusted logistic regression analyses showed that male sex, older age, and lower intake of lipids and polyunsaturated fatty acids and higher intake of carbohydrates in daily diet were associated with elevated serum IgG4 concentration. Subgroup analyses in men showed that older age, lower estimated glomerular filtration rates based on serum cystatin C (eGFR-cysC) levels, and higher hemoglobin A1c (HbA1c) levels were associated with elevated serum IgG4 concentration. Analyses in women showed that lower intake of lipids and fatty acids and higher intake of carbohydrates were significantly associated with elevated serum IgG4 concentration. One of the 15 participants who underwent secondary examinations was diagnosed with possible IgG4-related retroperitoneal fibrosis.ConclusionsElevated serum IgG4 levels in a Japanese general population were significantly associated with older age, male gender, and dietary intake of nutrients, with some of these factors identical to the epidemiological features of IgG4-RD.

Relationship between MRI findings and renal histopathology in IgG4-related tubulointerstitial nephritis.

MRI is expected to be a valuable tool for evaluating disease activity in immunoglobulin G4 (IgG4)-related tubulointerstitial nephritis (IgG4-TIN). However, the correlation between MRI findings and renal histopathological findings remains to be elucidated. This study aimed to clarify the correlation between MRI findings and renal histopathological findings in IgG4-TIN. This retrospective cross-sectional study investigated 26 patients with biopsy-proven IgG4-TIN who underwent simultaneous percutaneous kidney biopsies and abdominal MRI examinations at Toranomon Hospital or Toranomon Hospital Kajigaya between December 2007 and November 2022. We reviewed kidney biopsy specimens and scored the degree of inflammatory cell infiltration and interstitial fibrosis. We assessed abdominal MRI, specifically examining T1WI, T2WI, and DWI, for the presence of abnormal signals in the inferior pole of the kidney on the side where the kidney biopsy was performed. Spearman's correlation coefficient test was conducted to examine the relationship between the images and histological findings. For T1WI, eight cases showed a positive low-intensity signal, and 18 cases were negative. For T2WI, 19 cases were positive for a low-intensity signal, and seven cases were negative. In DWI, 23 cases were positive for a high-intensity signal, and one was negative. T1WI low-intensity signal and T2WI low-intensity signal were significantly correlated with interstitial fibrosis score (correlation coefficient 0.52 and 0.64). DWI revealed IgG4-TIN detected IgG4-TIN lesions with the highest sensitivity; however, the correlation with inflammatory cell infiltration score was not significant. Low-intensity signal on T2WI is useful for predicting the degree of fibrosis in IgG4-TIN.

IgG4-related sclerosing cholangitis associated with essential thrombocythemia: A case report

BACKGROUND The complexity of immunoglobulin G4 (IgG4)-related diseases and their potential connection to hematologic malignancies remains unclear. This article provided a review of the diagnosis and treatment of a patient with IgG4-related sclerosing cholangitis (SC) and essential thrombocythemia (ET), along with an analysis of relevant literature to enhance comprehension of this disease. CASE SUMMARY A 56-year-old male was admitted to two hospitals with deteriorating jaundice and pruritus prior to hospitalization. Beyond our expectations, the patient was first diagnosed with IgG4-SC and ET with the Janus kinase 2 V617F mutation. Interestingly, the administration of acetate prednisone significantly resulted in improvements in both IgG4-SC and ET. Clinicians need to pay attention to immune disorders and inflammation as they contribute to the development of various disease phenotypes. CONCLUSION When IgG4-SC is suspected without histopathological evidence, diagnostic therapy and long-term regular follow-up can lead to positive treatment outcomes. Clinicians should be mindful of the potential presence of concurrent hematologic diseases in patients with immune disorders.

Mass Forming Autoimmune Pancreatitis, Misdiagnosed as Pancreatic Cancer: Case Report

Autoimmune pancreatitis is characterized by infiltration of the pancreas parenchyma by immunoglobulin G4 (IgG4)-positive plasma cells, chronic inflammation, and fibrosis. It can affect the entire body depending on the subtype. Distinguishing mass-forming type autoimmune pancreatitis from pancreatic cancer can often be challenging. A 60-year-old male presented to our outpatient clinic with abdominal discomfort. Computed tomography revealed a 4.8 cm mass in the pancreatic head obstructing the common bile duct. Endoscopic ultrasound-guided fine needle biopsy and endoscopic retrograde cholangiopancreatography with biliary drainage were performed. Pathological examination revealed no malignant cells, but more than 20 IgG4-positive cells were observed. Following two weeks of steroid treatment, the patient’s symptoms improved, and follow-up imaging showed a reduction in the size of the pancreatic head mass. Herein, we report a case of mass-forming autoimmune pancreatitis initially misdiagnosed as pancreatic cancer.

The role of tissue IgG4 levels in steroid therapy in patients with idiopathic granulomatous mastitis

Idiopathic granulomatous mastitis (IGM) is a benign, chronic inflammatory lesion of the breast. Immunoglobulin G4 (IgG4) associated disease is rare in the breast. In our study, we aimed to evaluate the efficacy of steroid treatment on IgG4 levels in tissue in patients diagnosed with IGM. Between 2008 and 2017, 55 patients diagnosed with IGM in our clinic were included in the study. Demographic, clinical, microbiologic and histopathologic characteristics, treatment modality and recovery time were evaluated retrospectively. Patients were divided into 3 groups according to tissue IgG4 levels: negative (Group I), infrequently and slightly positive (Group II), and highly positive (Group III). Group I patients had a complete response rate of 77.8%. In the rest of the patients (22.2%), insufficient response was detected from the beginning of the treatment. In Group II, the response rate was 91.3% and the permanent success rate after treatment was 87.0%. Although group III patients had a complete response at the beginning (95.65%), they relapsed in a short period of time (26.1%) after discontinuation of steroid treatment. At least one steroid-related side effect was observed in 47 (85.8%) patients in all groups. There is no consensus on the dose and duration of immunosuppressive treatment in IGM. In this study, responses to steroid treatment according to IgG4 concentration in pathologic breast tissue and recurrences after the end of treatment were determined. We think that high IgG4 concentration in the tissue is associated with recurrence and other immunosuppressive drugs should be added as maintenance after steroid treatment.

Efficacy and Safety of Bleselumab in Preventing the Recurrence of Primary Focal Segmental Glomerulosclerosis in Kidney Transplant Recipients: A Phase 2a, Randomized, Multicenter Study.

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage kidney disease and frequently recurs after kidney transplantation. Recurrent FSGS (rFSGS) is associated with poor allograft and patient outcomes. Bleselumab, a fully human immunoglobulin G4 anti-CD40 antagonistic monoclonal antibody, disrupts CD40-related processes in FSGS, potentially preventing rFSGS. A phase 2a, randomized, multicenter, open-label study of adult recipients (aged ≥18 y) of a living or deceased donor kidney transplant with a history of biopsy-proven primary FSGS. The study assessed the efficacy of bleselumab combined with tacrolimus and corticosteroids as maintenance immunosuppression in the prevention of rFSGS >12 mo posttransplantation, versus standard of care (SOC) comprising tacrolimus, mycophenolate mofetil, and corticosteroids. All patients received basiliximab induction. The primary endpoint was rFSGS, defined as proteinuria (protein-creatinine ratio ≥3.0 g/g) with death, graft loss, or loss to follow-up imputed as rFSGS, through 3 mo posttransplant. Sixty-three patients were followed for 12 mo posttransplantation. Relative decrease in rFSGS occurrence through 3 mo with bleselumab versus SOC was 40.7% (95% confidence interval, -89.8 to 26.8; P = 0.37; absolute decrease 12.7% [95% confidence interval, -34.5 to 9.0]). Central-blinded biopsy review found relative (absolute) decreases in rFSGS of 10.9% (3.9%), 17.0% (6.2%), and 20.5% (7.5%) at 3, 6, and 12 mo posttransplant, respectively; these differences were not statistically significant. Adverse events were similar for both treatments. No deaths occurred during the study. In at-risk kidney transplant recipients, bleselumab numerically reduced proteinuria occurrence versus SOC, but no notable difference in occurrence of biopsy-proven rFSGS was observed.

Primary sclerosing cholangitis with IgG4-positive plasma cells in bile duct biopsies - Frequency and characterization.

Patients diagnosed with primary sclerosing cholangitis (PSC) but with characteristics of immunoglobulin G4 (IgG4)-associated cholangitis (IAC) have been described. IAC often presents with biliary IgG4-positive plasma cell (IgG4+ PC) infiltration and responds to corticosteroids. In PSC, the frequencies or implications of biliary IgG4+ PC are unknown. We aimed to characterize the phenomenon of biliary IgG4+ PC in patients with an established PSC diagnosis. Bile duct biopsies from 191 surveillance or therapeutic endoscopic retrograde cholangiography of 58 PSC patients were retrospectively analyzed for IgG4+ PC infiltration. Patients with ≥10 IgG4+ PC per high-power field (HPF) were identified and characterized by clinical parameters, including serum IgG4 and cholangiographic presentations. Altogether 39.7% of the PSC patients showed ≥10 IgG4+ PC/HPF in bile duct biopsies. Patients with biliary IgG4+ PC infiltration were significantly younger at diagnosis of PSC (P = 0.023). There was no association between biliary IgG4+ PC infiltration and transplant-free survival (P = 0.618). Patients with IgG4+ PC infiltration in bile duct biopsies showed significantly higher baseline (P = 0.002) and maximum (P = 0.001) serum IgG4 compared to those without. Biliary IgG4+ PC infiltration was associated with high-grade bile duct strictures (P = 0.05). IgG4-positive plasma cell infiltrations were found multifocally in 72.7% of this subgroup of PSC patients. IgG4+ PC ≥10/HPF can be found abundantly in bile duct biopsies in PSC. Histological findings correlated with serum IgG4, age, and high-grade bile duct strictures. IgG4+ PC was located multifocally, hinting at a systemic biliary phenotype.

Clinical and serological characteristics of patients allergic to LTP.

Allergy to lipid transfer proteins (LPT) is common in Mediterranean Europe, and it causes severe reactions in patients and affects multiple foods, impairing the quality of life. This study aimed to describe the clinical and sensitization profile of patients with LTP syndrome and to determine a clinical pattern of severity. Molecular diagnosis is shown in a broad population through microarrays. This study was performed at the LTP Allergy Consultation of the Reina Sofia Hospital in Murcia, Spain. We analyzed the patients' characteristics, reactions, cofactors, food implicated, quality of life, skin prick test to food and aeroallergens, and serologic parameters, such as total immunoglobulin E, peach LTP (Pru p 3 IgE) and immunoglobulin G4, and microarray Immuno Solid-phase Allergen Chip (ISAC). We related the severity of the reactions with other variables. We presented a series of 236 patients diagnosed with LTP allergy, 54.66% suffering from anaphylaxis, 36.02% from urticaria angioedema, and 9.32% from oral allergy syndrome. The most frequently implicated food was peach, producing symptoms in 70% of patients, followed by walnut in 55%, peanut in 45%, hazelnut in 44%, and apple in 38% patients. Regarding the food that provoked anaphylaxis, walnut was the most frequent instigator, along with peach, peanut, hazelnut, almond, sunflower seed, and apple. According to the severity of LPT reaction, we did not discover significant differences in gender, age, food group involved, and serologic parameters. We found differences in the presence of cofactors, with 48.84% of cofactors in patients with anaphylaxis, compared to 27.1% in patients without anaphylaxis and in family allergy background (P < 0.0001). In our series of patients, 54% presented anaphylaxis, and the foods that most frequently produced symptoms were peaches, apples, and nuts. Cofactors and family allergy backgrounds were associated with the severity of LPT reaction.

IgG4-related orbital disease presenting as optic neuropathy: A rare presentation and review of literature

A 74-year-old male presented with a sudden drop of vision in the left eye for 5 days. He had a relative afferent pupillary defect and visual acuity of counting finger at 1 m in the left eye. Fundus showed a hyperaemic disc in the left eye. Ocular movements were full. He had uncontrolled diabetes mellitus. A possibility of anterior ischemic optic neuropathy was considered. The patient was lost for follow-up and came back 2 months later with visual acuity of perception of light in the left eye with features suggestive of orbital apex syndrome. Histopathology was confirmatory of immunoglobulin G4 (IgG4) disease. IgG4 disease presenting as optic neuropathy can be an early manifestation of orbital involvement.

Hypertrophic Pachymeningitis, Associated with Eosinophilic Granulomatosis with Polyangiitis, and ANCA-Negative Serology.

Hypertrophic pachymeningitis (HP) is a disease with diverse aetiologies, including the autoimmune one, either associated with antineutrophil cytoplasmic antibodies or immunoglobulin G4. A 65-year-old woman with a history of systemic arterial hypertension, presented with intense progressive headaches. HP and hemispheric vasogenic oedema were observed by nuclear magnetic resonance (NMR) study. During the six months before the headache, she had developed progressive hearing loss which she attributed to age. A biopsy of dura mater showed necrotising vasculitis with peripheral inflammatory infiltrate, made up of accumulations of epithelioid cells and multinucleated giant cells, and abundant eosinophils. A final diagnosis of HP with eosinophilic granulomatosis with polyangiitis (EGPA) was made. The patient had eosinophilic granulomatosis with polyangiitis (EGPA) histology, ANCA-negative serology and HP. This case is important because it shows that EGPA seems to have a spectrum of clinical diseases, including HP with negative serology, and bilateral sensorineural hearing loss. We are facing a wide spectrum of EGPA, breaking the paradigm of only systemic involvement. Hypertrophic pachymeningitis (HP) has several aetiologies; if the systemic investigation is not contributory to a diagnosis, a meningeal biopsy is necessary.This is the first case report of HP, associated with eosinophilic granulomatosis with polyangiitis (EGPA), and ANCA-negative serology.EGPA is probably a spectrum of diseases with predominant systemic involvement, but there may be cases where there is histological evidence, without the systemic context or positive serology.