International Consensus Guidance Statement on the Management and Treatment of IgG4-Related Disease

Burden of Glucocorticoid Use and Risk of Toxicities Among Patients with Immunoglobulin-G4-Related Disease: A Retrospective US-Based Claims Study

INTRODUCTION

Glucocorticoids are commonly used to treat immunoglobulin G4-related disease (IgG4-RD), but there is limited real-world evidence describing glucocorticoid-related toxicities in this population. This study assessed glucocorticoid use and toxicities during the first year after diagnosis among patients with IgG4-RD.

METHODS

The IQVIA PharMetrics® Plus database was used to identify adults with IgG4-RD using a validated algorithm. Patients were stratified according to glucocorticoid use during the 12-month study period following the first observed IgG4-RD-related diagnosis (index date): low glucocorticoid use (prednisone equivalent daily dose [PEDD] < 5 mg/day) or high glucocorticoid use (PEDD ≥ 5 mg/day). Incident glucocorticoid-related toxicities were assessed during the study period and incidence was compared between groups using Chi-square tests.

RESULTS

Among 295 patients with IgG4-RD, 150 (50.8%) had low glucocorticoid use, and 145 (49.2%) had high glucocorticoid use during the study period. In each glucocorticoid group, mean PEDD was highest in the 3 months post-index and subsequently decreased. At 12 months post-index, 24.7% of the low glucocorticoid use group and 60.7% of the high glucocorticoid use group were receiving glucocorticoids. The high glucocorticoid use group had a significantly higher mean (± standard deviation) number of incident glucocorticoid-related toxicities (1.8 ± 1.7 vs. 1.2 ± 1.3) and more frequently had ≥ 3 glucocorticoid-related toxicities (29.0% vs. 13.3%; both p < 0.01) compared to the low glucocorticoid use group. Specifically, cardiovascular- (29.0% vs. 18.7%), gastrointestinal- (29.7% vs. 16.0%), and infection-related (31.0% vs. 17.3%) toxicities were significantly more common in the high glucocorticoid use group than the low glucocorticoid use group (all p < 0.05).

CONCLUSIONS

In this retrospective, claims-based analysis, high glucocorticoid use was seen in half of patients with IgG4-RD during the first year following diagnosis. Patients with high glucocorticoid use experienced significantly more incident glucocorticoid-related toxicities than those with low use during this first year.

'Can we cure IgG4-related diseases?'

IgG4-related disease (IgG4-RD), recognized as a novel clinical entity, is a rare, chronic, immune-mediated systemic fibroinflammatory disorder of unknown origin with either synchronous or metachronous multi-organ involvement. Although the pathogenic mechanism remains unclear, possible multipathogenic factors such as genetic backgrounds, disease-specific or related antigens, and abnormal innate or adaptive immunity may be involved. Many immunocytes, including neutrophil extracellular trap, M2 macrophage, plasmablast, B cells, and T-cells (Th2-CD4+T, follicular helper T cells, and CD4+SLAMF7+cytotoxic T cells) play important roles in the pathogenesis. Conventional therapies with glucocorticoid or rituximab in combination with/without immunomodulators are recommended in all symptomatic patients with active IgG4-RD. Because of a few of randomized clinical trials, the comprehensive management for IgG4-RD has not been established yet. Targeted treatment approaches against the plasmablast to B cell lineage and the CD4+SLAMF7+cytotoxic T cell seem to be promising for the future-directed treatment.

IgG4-related disease in the nervous system

IgG4-related disease (IgG4-RD) is a recently described multisystemic disorder with a spectrum of manifestations that continue to be described. Nonetheless, there are recognised distinct patterns of disease. Neurological involvement is rare, particularly in isolation, but IgG4-RD may present with orbital disease, hypophysitis or pachymeningitis. Typically, it is highly responsive to treatment. This review highlights neurological manifestations of IgG4-RD and emphasises the importance of a high index of clinical suspicion to facilitate investigation and appropriate management, avoiding irreversible tissue damage and neurological dysfunction. We present a treatment algorithm for suggested management of IgG4-RD affecting the nervous system.

IgG4-related Ophthalmic Disease: A Nationwide Multicenter Study in Korea

PURPOSE

To investigate the clinical characteristics and treatment outcomes of IgG4-related ophthalmic disease (IgG4-ROD) in Korean patients.

DESIGN

A multicenter, retrospective case series study.

PARTICIPANTS

Three hundred and forty-one patients with IgG4-ROD from 24 hospitals in Korea.

METHODS

The medical records of all patients with IgG4-ROD were reviewed, which were consistent with comprehensive diagnostic criteria. The demographic, clinical, histopathological, and laboratory data were also collected.

MAIN OUTCOME MEASURES

Frequencies of extra-lacrimal gland and extraorbital involvement, and treatment outcomes with potential predisposing factors.

RESULTS

Among the 341 patients with IgG4-ROD who were enrolled, 155 (45.5%) had definite IgG4-ROD. Extra-lacrimal gland involvement was observed in 53 patients (34.2%) and associated with older age, male sex, unilaterality, and higher serum IgG4 levels. Extraorbital involvement was observed in 52 of 77 (67.5%) patients with definite IgG4-ROD who underwent adequate systemic evaluation. Regarding treatment outcomes, 130 with definite IgG4-ROD who were followed up for more than 6 months were included for the analysis; 93 (71.5%) achieved remission, and 40 (30.8%) attained steroid-free remission. Surgical debulking was significantly associated with remission and steroid-free remission, whereas initial use of an immunomodulator with a steroid showed no significant association with the treatment outcome. The highest serum IgG4 tertile was negatively associated with steroid-free remission. Relapses occurred in 24 (28.6%) of 86 patients who experienced remission, and underlying diabetes was an associated risk factor.

CONCLUSIONS

Extraorbital involvement was detected in more than half of the patients with definite IgG4-ROD, emphasizing that broad systemic evaluation is warranted for these patients. Disease remission was achieved in 71.5% of patients, but relapse occurred in a significant number of patients. Steroid-free remission was positively associated with surgical debulking. These findings suggest that the surgical debulking of the lesions and patient tolerability to steroid therapy may affect treatment outcomes in IgG4-ROD.

Ipomoea carnea Jacq. ameliorates formalin-induced paw inflammation in rats through modulation of oxidative and inflammatory pathways

Ipomoea carnea Jacq. (I. carnea) belongs to Convolvulaceae family, that is being for the management of pain and inflammation. Since long current research was conducted to study anti-inflammatory potential of aqueous methanolic extract of Ipomoea carnea (ICE). Preliminary proximate study and HPLC were carried out for the phytochemical characterization. The safety of ICE was ensured by acute oral toxicity study. In vitro anti-inflammatory potential of ICE was evaluated using BSA denaturation methods and egg albumin. In vivo inflamed paw rat model using formalin was done at doses of 150, 300, and 600 mg/kg. Diameter of the Paw, weight changes in the body, and biochemical and hematological markers were quantified. By means of ELISA IL-6, PGE-2, TNF-α, HSP-70, SOD, CAT, and MDA levels were measured. The mRNA expression of different inflammatory genes was evaluated by qRT-PCR. Effects of ICE were noted by histological and radiological findings. Phytochemistry of ICE identified the presence of different secondary metabolic constituents and HPLC identified the various phenolic compounds in the extract. Acute oral toxicity results showed that LD50 of the plant was greater than 2000 mg/kg. ICE demonstrated significant inhibition of egg albumin denaturation and protein denaturation in BSA. In vivo formalin-induced paw inflammation model demonstrated that ICE substantially decreased the severity of inflammation, in a dose-dependent manner. Hematological and biochemical parameters were improved and histological examination revealed reduction in paw inflammation, pannus formation, and bone degradation dose-dependently. The expression of pro-inflammatory genes was down-regulated with simultaneous up-regulation of anti-inflammatory genes by ICE. This study revealed that ICE possesses potent anti-inflammatory capacity thus backup its traditional use in the treatment of inflammation.

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

Unusual Presentation of an Orphan Syndrome Masquerading as Castleman Disease in a Young Adult: Diagnostic Challenges and Clinical Implications: A Case Report

IgG4-related disease (IgG4-RD) is a rare and diagnostically challenging fibroinflammatory condition characterized by diverse clinical presentations. We present the case of a 33-year-old male with a progressively enlarging right groin swelling over 6 months. A similar episode occurred 4 years prior in Nepal, with an inconclusive biopsy. Initial investigations pointed to chronic subcutaneous infectious granulomatous disease with lymphadenopathy. Following multiple missed appointments, the patient underwent excision of a soft tissue mass and lymph nodes. Histopathology revealed features consistent with IgG4-RD, including follicular hyperplasia and a Castleman disease-like pattern, negative for malignancy. This case underscores the diagnostic challenges of IgG4-RD and the importance of considering it in the differential diagnosis of chronic lymphadenopathy. Timely follow-up, histological evaluation, and awareness of IgG4-RD diagnostic criteria are crucial for proper management and avoiding delayed treatment.

Epidemiological and economical burden of cholestatic liver disease

The main cholestatic liver diseases comprise primary sclerosing cholangitis, primary biliary cholangitis, and IgG4-related cholangitis. Despite being classified as rare diseases, these are becoming gradually more important in the field of hepatology since their incidence is slowly rising while the viral hepatitis burden is declining. Cholestatic liver diseases now rank among the 3 most frequent indications for liver transplantation in many Western countries. An accurate understanding of the epidemiology and burden of disease on both the individual and society of cholestatic diseases is of great importance. This review aims to provide a comprehensive overview of the current literature on the epidemiology, health-related quality of life, and economic burden of primary sclerosing cholangitis, primary biliary cholangitis, and IgG4-related cholangitis.

Inflammatory Aneurysm of the Common Iliac Artery With Elevated Serum Levels of Immunoglobulin G4 Manifesting After Endovascular Aneurysm Repair: A Case Report

Inflammatory aneurysms (IAs) are characterized by the thickening of the arterial wall and fibrosis of periarterial tissues. Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is related to IAs, and about half of IA cases are considered IgG4-related. Although some cases of inflammation after endovascular aneurysm repair (EVAR) have been reported, its relationship with the serum levels of IgG4 has rarely been discussed. Here, we report on a patient diagnosed with and treated for an IA with elevated serum levels of IgG4 following EVAR. An 83-year-old man presented with a bilateral common iliac artery aneurysm. We observed no inflammatory features in his vital signs, laboratory test results, or computed tomography (CT) images. The patient was diagnosed with a non-inflammatory bilateral common iliac artery aneurysm. EVAR was performed using an infrarenal bifurcated stent graft (diameter, 31 mm; length, 15 cm; GORE EXCLUDER AAA Endoprosthesis (WL Gore & Associates, Inc., Flagstaff, AZ, USA)), with an ipsilateral limb stent graft (diameter, 12 mm; length, 7 cm; GORE EXCLUDER) deployed in the left external iliac artery and a contralateral limb stent graft (diameter, 12 mm; length, 14 cm; GORE EXCLUDER) deployed in the right external iliac artery. The patient was discharged in good condition. However, signs of inflammation were observed approximately one month after EVAR. CT images demonstrated the periarterial thickening of the common iliac arteries, and 18F-fluorodeoxyglucose positron emission tomography-CT revealed increased metabolic activity overlying the thickened periarterial tissue. The serum levels of IgG4 and soluble interleukin-2 receptor (sIL-2R) were elevated. The patient underwent steroid therapy based on the suspicion of IgG4-related IA of the common iliac arteries, resulting in reductions of inflammatory signs and periarterial thickening. However, when steroids were reduced, hydronephrosis, periarterial thickening, and increased serum IgG4 and sIL-2R levels were observed. The patient was diagnosed with a relapsed IA and treated with an increased steroid dosage. IAs may occur following EVAR. Steroid therapy may be an effective treatment for post-EVAR IAs, similar to common IAs. Long-term follow-up is desirable to monitor patients for the recurrence of inflammation during the treatment of post-EVAR IAs.

Differences in Fibroinflammatory Activity Shown on 68Ga-FAPI-04 and 18F-FDG PET/CT in the Two Subtypes of IgG4-Related Disease

IgG4-related disease (IgG4-RD) is a highly heterogeneous autoimmune disease. Recently, 2 subtypes of IgG4-RD, proliferative and fibrotic, were defined according to patients' clinicopathologic characteristics. The purpose of this study was to determine the difference in fibroinflammatory activity shown on 68Ga-FAPI-04 and 18F-FDG PET/CT in the proliferative and fibrotic IgG4-RD subtypes. Methods: Thirty-seven newly diagnosed IgG4-RD patients (29 of the proliferative subtype and 8 of the fibrotic subtype) who had undergone 68Ga-FAPI-04 and 18F-FDG PET/CT were enrolled. SUVmax and target-to-background ratio (TBR) of IgG4-RD lesions were measured. To evaluate the weight of fibroinflammatory activity, the PET index of a lesion was calculated as the quotient of SUVmax or TBR of 68Ga-FAPI-04 and that of 18F-FDG. For the assessment of the global disease in an individual patient, the PET index was defined as the ratio of SUVmean of all involved lesions in 68Ga-FAPI-04 PET/CT to that in 18F-FDG. Results: The 18F-FDG uptake values of the most prominent lesions in the proliferative and fibrotic subtypes were similar; however, the proliferative subtype showed significantly higher uptake of 68Ga-FAPI-04 than did the fibrotic subtype (SUVmax, 17.67 ± 7.46 vs. 10.93 ± 2.22, P = 0.005; TBR, 15.49 ± 8.23 vs. 9.25 ± 3.00, P = 0.015). The PET index of proliferative-subtype patients was higher than that of fibrotic-subtype patients (1.46 ± 0.41 vs. 1.14 ± 0.39, P = 0.039). The PET index of pancreatobiliary disease was significantly higher than that of head-and-neck disease, fibrosis or aortitis, lymph nodes, and another disease subtype (P < 0.05). After first-line treatment, patients with a PET index of at least 1.5 had significantly shorter relapse-free survival than those with a PET index of less than 1.5 (22.0 mo vs. not reached, P < 0.0001; hazard ratio, 13.46; 95% CI, 2.236-81.03). Conclusion: The proliferative subtype of IgG4-RD had a greater weight of fibroinflammatory activity than that of the fibrotic subtype. The PET index, a marker of the weight of fibroinflammatory activity, is predictive of relapse-free survival of IgG4-RD.

A Case of IgG4-Related Disease Presenting With Concurrent Uveitis, Posterior Scleritis, Serous Retinal Detachment, and Choroidal Thickening Mimicking Intraocular Lymphoma

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition characterized by tumor-like lesions, dense lymphoplasmacytic infiltrates rich in IgG4-positive plasma cells, and often elevated serum IgG4 levels. Ocular involvement is common, typically affecting the lacrimal glands and extraocular muscles. However, intraocular manifestations such as uveitis and scleritis are less frequent. We report the case of a 66-year-old Japanese man presenting with bilateral uveitis, posterior scleritis, serous retinal detachment, and choroidal thickening, initially mimicking intraocular lymphoma. His serum IgG4 and soluble interleukin-2 receptor levels were markedly elevated. Magnetic resonance imaging showed posterior eyeball wall thickening with restricted diffusion and diffuse thickening of the nasal mucosa and hard palate mucosa. Computed tomography revealed an asymptomatic retroperitoneal mass around the aorta. Salivary gland biopsy confirmed dense lymphoplasmacytic infiltration with increased IgG4-positive plasma cells (80/HPF) and an elevated IgG4/IgG ratio (~50%), consistent with IgG4-RD. The patient responded well to oral corticosteroid therapy with improvement in visual acuity. This case highlights the rare but important presentation of intraocular manifestations in IgG4-RD.

Inebilizumab for Treatment of IgG4-Related Disease

BACKGROUND

IgG4-related disease is a multiorgan, relapsing, fibroinflammatory, immune-mediated disorder with no approved therapy. Inebilizumab targets and depletes CD19+ B cells and may be effective for treating patients with IgG4-related disease.

METHODS

In this phase 3, multicenter, double-blind, randomized, placebo-controlled trial, adults with active IgG4-related disease underwent randomization in a 1:1 ratio to receive inebilizumab (300-mg intravenous infusions on days 1 and 15 and week 26) or placebo for a 52-week treatment period. Participants in both groups received identical glucocorticoid tapers. Glucocorticoids were allowed to treat disease flares, but background immunosuppressants were not permitted. The primary end point was the first treated, adjudicated disease flare during the treatment period, assessed in a time-to-event analysis. Key secondary end points were the annualized flare rate and treatment-free and glucocorticoid-free complete remission.

RESULTS

A total of 135 participants with IgG4-related disease underwent randomization: 68 participants were assigned to receive inebilizumab and 67 were assigned to receive placebo. Treatment with inebilizumab reduced flare risk; 7 participants (10%) in the inebilizumab group had at least one flare, as compared with 40 participants (60%) in the placebo group (hazard ratio, 0.13; 95% confidence interval [CI], 0.06 to 0.28; P<0.001). The annualized flare rate was lower with inebilizumab than with placebo (rate ratio, 0.14; 95% CI, 0.06 to 0.31; P<0.001). More participants in the inebilizumab group than in the placebo group had flare-free, treatment-free complete remission (odds ratio, 4.68; 95% CI, 2.21 to 9.91; P<0.001) and flare-free, glucocorticoid-free complete remission (odds ratio, 4.96; 95% CI, 2.34 to 10.52; P<0.001). Serious adverse events occurred during the treatment period in 12 of the participants (18%) who received inebilizumab and 6 of the participants (9%) who received placebo.

CONCLUSIONS

Inebilizumab reduced the risk of flares of IgG4-related disease and increased the likelihood of flare-free complete remission at 1 year, confirming the role of CD19-targeted B-cell depletion as a potential treatment for IgG4-related disease. (Funded by Amgen; MITIGATE ClinicalTrials.gov number, NCT04540497.).

Comparison of clinical features between patients with and without renal involvement in IgG4-related disease

OBJECTIVE

The kidney is one of the organs most frequently affected in immunoglobulin G4-related disease (IgG4-RD). Early identification of IgG4-RD with renal injury by clinical features is a current challenge. There is a paucity of data regarding the clinical features of renal involvement in IgG4-RD.

MATERIALS

Patients with the diagnosis of IgG4-RD with and without renal injury were included in the retrospective cohort study. Cox regression analyses were used to investigate the risk factors for disease relapse and to construct the nomogram model.

RESULTS

From December 2014 to February 2022, 54 patients with IgG4-RD were retrospectively enrolled. Renal involvement in IgG4-RD was observed in 55.6% of the patients. The differences of age and lacrimal gland accumulation were statistically significant (P < 0.001, and P = 0.034, respectively). Age was significantly higher in the kidney injury group. Regarding laboratory findings, basophil counts, hemoglobin levels, and serum cholinesterase level were significantly lower in patients with renal involvement (P = 0.033, P = 0.006 and P = 0.019). Erythrocyte sedimentation rate level was significantly higher in patients with renal involvement (P = 0.017). Seven (23.4%) patients in the kidney injury group relapsed during follow-up with mean recurrence time 9.86 ± 7.08 months. Early diagnosis plays a key role in patient outcomes. Female, elevated erythrocyte sedimentation rate level, and elevated complement component 4 are the risk factors for the disease relapse of IgG4-RD patients. Moreover, an effective nomogram model has been developed to predict disease relapse in patients with IgG4-RD.

Clinical characterization of aortitis and periaortitis: study of 134 patients from a single university hospital

Aortitis and periaortitis refer to the inflammation of the aortic wall and the surrounding tissues. Both conditions are associated with various diseases and express nonspecific manifestations. Early diagnosis and treatment are crucial to improve the prognosis of the disease. This study aimed to assess the causes and main clinical features of aortitis and periaortitis in patients from a single centre in Spain. Observational, retrospective study of patients diagnosed with aortitis or periaortitis at a Spanish referral center over the last decade. 134 patients (87 female; mean age of 55.1 ± 9.1 years) were recruited, 132 of which had aortitis and two periaortitis. Aortitis was associated with giant cell arteritis (n = 102), Takayasu's arteritis (n = 6), IgG4-related disease (n = 6), infectious diseases (n = 3), malignancy (n = 1), drugs (n = 1), isolated aortitis (n = 1), and other immune-mediated inflammatory diseases (IMIDs) (n = 12). IMIDs included were Sjögren's syndrome (n = 2), sarcoidosis (n = 2), rheumatoid arthritis (n = 2), axial spondyloarthritis (n = 2), inflammatory bowel disease (n = 1), primary biliary cirrhosis (n = 1), idiopathic pulmonary fibrosis (n = 1), and polyarteritis nodosa (n = 1). Periaortitis was due to idiopathic retroperitoneal fibrosis in both cases. Imaging techniques used for diagnosis included 18F-FDG PET/CT scan (n = 133), CT-angiography (n = 44), and/or MRI-angiography (n = 33). Polymyalgia rheumatica (52.2%) and asthenia (53.7%) were the most common manifestations, followed by limb claudication (23.9%) and inflammatory back pain (26.9%). Acute-phase reactants were typically increased. Aortitis is a common condition and may be associated with multiple non-infectious diseases. Its clinical presentation is often unspecific, requiring a high level of suspicion to get an early diagnosis and treatment.

Collapsing Focal Segmental Glomerulosclerosis With Concurrent IgG4 Nephropathy

A 41-year-old male with a history of chronic kidney disease, hypertension, and psoriasis was referred to the nephrologist for worsening kidney function associated with nephrotic range proteinuria. The patient had no symptoms, but the initial workup showed elevated erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), positive double-stranded DNA antibody(anti-DsDNA) but normal complement levels, normal antinuclear antibody (ANA) and negative beta-glycoprotein-1 IgG, IgM, and IgA. Further, the workup revealed the patient had elevated total immunoglobulin as well as elevated IgG subsets 2, 3, and 4. He was also found to have a high variant of apolipoprotein L1 (APOL1). A renal biopsy revealed diffuse active, subacute, and chronic interstitial inflammation, plasma cell-rich (25% IgG4 positive), confirming IgG4-related tubulointerstitial nephritis with concomitant IgG4 dominant, PLA2R negative membranous glomerulonephritis. There was also a severe podocytopathy in the form of diffuse segmental/global collapsing glomerulopathy with sclerosing changes as well as global glomerulosclerosis, extensive tubular atrophy with mild interstitial changes suggestive of a variant of focal segmental glomerulosclerosis (FSGS). A diagnosis of APOL-1 collapsing glomerulopathy with IgG4 nephropathy was made based on clinical and pathological findings. The patient's kidney function stabilized, and IgG4 levels returned to normal after the patient was initiated on 60 mg daily prednisolone. The steroid was tapered off and the patient was started on mycophenolate mofetil 1000 mg twice daily. To our knowledge, this is the first reported case of IgG4-related kidney disease with concurrent severe APOL1-associated collapsing glomerulopathy.

Clinical and Imaging Pulmonary Manifestations in IgG4-Related Disease

OBJECTIVES

The aims of this study were to describe the frequency of pleuropulmonary computed tomography (CT) findings in patients with IgG4-related disease (IgG4-RD) and to compare clinical and laboratory characteristics between patients with and without pleuropulmonary involvement in chest CT.

METHODS

This is a study conducted within the IgG4-RD study group of the Argentine Society of Rheumatology (GESAR IgG4) cohort of patients with IgG4-RD. Member centers of the group were requested to submit pulmonary CT scans of the patients. Lung lesions were classified into 4 subtypes: (1) nodules, (2) ground-glass opacity, (3) interstitial-alveolar involvement, and (4) bronchovascular involvement. The presence of pleural involvement and mediastinal adenopathy was also assessed.

RESULTS

We examined data from 28 patients, with 17 (61%) showing pulmonary involvement. The subtypes of pulmonary involvement, in order of frequency, were as follows: type 4 (n = 17, 100%), type 3 (n = 10, 59%), type 2 (n = 6, 36%), and type 1 (n = 5, 29%). Pleural lesions were observed in 2 (12%) cases, and mediastinal adenopathies were found in 4 (23%) cases. No demographic, clinical, or laboratory differences were noted between patients with and without pulmonary involvement, except for serum levels of IgG4, which were higher among patients without pulmonary involvement (339.0 [293.1-1592.1 mg/dL] vs 2869 [1156.3-4037.4 mg/dL]; p = 0.022).

CONCLUSIONS

In this case series, the predominant subtype of pulmonary involvement was septal thickening and increased bronchovascular tissue. Patients with and without pleuropulmonary involvement exhibited similar clinical and laboratory manifestations, except for serum IgG4, which was higher in patients without pleuropulmonary involvement.

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

BACKGROUND

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

CASE PRESENTATION

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

DISCUSSION

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

CONCLUSION

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

Thalidomide can effectively prevent relapse in IgG4-related disease outweighing its side effects: a multicentre, randomised, double-blinded, placebo-controlled study

OBJECTIVES

To investigate the effects of thalidomide in preventing disease relapse with 'zero' glucocorticoids (GCs) usage in IgG4-related disease (IgG4-RD).

METHODS

This was a multicentre, randomised, double-blinded, placebo-controlled study, in which eligible patients in disease active status were randomised into 2 groups (group 1: GCs+Thalidomide; group 2: GCs+Placebo) at a 1:1 ratio. The primary outcome of this trial was the disease relapse rate at month 12, whereas the secondary outcomes were the disease remission rate at month 12 and the incidence of adverse events (AEs).

RESULTS

A total of 60 patients were randomised, and 57 patients (GCs+Thalidomide: 29; GCs+Placebo: 28) finished the study per protocol. The relapse rates of the GCs+Thalidomide and GCs+Placebo groups at month 12 were 13.8% and 67.8%, respectively. A 100% response rate was observed in both treatment group, while the remission rates of the GCs+Thalidomide and GCs+Placebo groups were 75.8% and 32.1%, respectively. In total. 49 AEs were recorded in 35 participants, in which 4 were graded as moderate, and 45 were graded as mild. The risk-benefit analysis based on the evaluation of rates of disease relapse and moderate AEs within the 12-month follow-up showed a NNT (number needed to treat) of 2 and a NNH (number needed to harm) of 8 for thalidomide treatment.

CONCLUSIONS

Thalidomide can effectively prevent relapse in IgG4-RD outweighing its side effects, which indicating that thalidomide can be a potential safe therapeutic option for disease relapse prevention in parallel with steroid sparing in IgG4-RD.

The Management of IgG4-Related Disease in Children: A Systematic Review

Background/Objectives: IgG4-related disease (IgG4-RD) is a multi-organ disease with greatly varying therapeutic approaches and a lack of specific treatment algorithms. This systematic review aimed to determine the therapeutic approaches for pediatric IgG4-RD in real-word practice. Methods: We searched PubMed and Google Scholar for articles on pediatric IgG4-RD cases published in English from 2012 to August 2024, focusing on treatments and outcomes. Study type, treatment(s), dose/regimen, age and sex, organ(s) involved, and treatment outcomes were manually extracted from each study. Results: Of the 219 studies identified, we analyzed 81 studies, including 114 pediatric IgG4-RD cases. Fifty-seven percent of patients suffered from multi-organ disease and required several treatment schemes. Around 75% received steroids, alone or in combination, regardless of the organ affected. The treatment outcomes were positive in most cases, although relapses occurred in approximately 30% of patients, usually upon steroid tapering. Other common therapeutic approaches included immunosuppressants, often used as steroid-sparing agents, with azathioprine and mycophenolate mofetil being the most common; surgery for localized disease; and biologics, mainly rituximab, used in more severe/refractory cases. Uncommon but effective therapies included adalimumab and ruxolitinib. Drug combinations seemed to be more efficacious than monotherapies across studies. Patients > 10 years old more frequently received aggressive approaches (surgery and rituximab) and more often experienced relapses. Relapse rates were higher among females. Conclusions: This review highlights the use of systemic steroids as an effective first-line treatment for pediatric IgG4-RD, but also underscores the use of non-steroid-based alternatives in combination with steroids or other immunosuppressants for the effective management of IgG4-RD.

Multicentre, 26-week, open-label phase 2 trial of the JAK inhibitor filgotinib in Behçet's disease, idiopathic inflammatory myopathies and IgG4-related disease: DRIMID study protocol

INTRODUCTION

Research into novel therapies for rare, immune-mediated inflammatory diseases (IMIDs) faces significant challenges, including small patient populations, complex clinical trial design and difficulties in patient recruitment. Patients with Behçet's disease (BD), idiopathic inflammatory myopathies (IIM) and IgG4-related disease (IgG4-RD) typically undergo treatment involving prolonged administration of high-dose glucocorticoids and immunosuppressants. Both are associated with an increased risk of infection. Additionally, glucocorticoids carry long-term toxicity risks. Thus, there is an urgent need to develop more targeted and effective anti-inflammatory treatments. Given the activation of the type 1 interferon pathway in BD, IIM and IgG4-RD, inhibition of the Janus kinase (JAK) STAT pathway emerges as a promising therapeutic strategy. The Drug Rediscovery in IMIDs (DRIMID) consortium aims to conduct a prospective pilot basket trial to investigate the effects of filgotinib, a JAK1 preferential inhibitor approved for ulcerative colitis and rheumatoid arthritis, on disease activity, quality of life and safety in patients with refractory BD, IIM and IgG4-RD.

METHODS AND ANALYSIS

In this investigator-initiated, multicentre, open-label phase 2 study, up to 60 patients with rare IMIDs will be enrolled for a 26-week treatment period with filgotinib 200 mg once daily. The trial consists of two stages, each involving a consecutively treated cohort of up to 20 patients per disease. An interim analysis is conducted between these stages, where the trial will proceed only in diseases showing potential effectiveness. Baseline, 3-month and 6-month assessments will include data on quality of life, disease activity, corticosteroid toxicity and biomarkers. The coprimary endpoints are disease activity and quality of life across and within each disease.

ETHICS AND DISSEMINATION

The study received approval from the Medical Research Ethics Committee in Utrecht, Netherlands. A Data Safety Monitoring Board has been established to monitor the trial's safety and progress.

TRIAL REGISTRATION NUMBER

NCT06285539.

IgG4-RD-Associated Mikulicz Syndrome Without Classic Systemic Involvement-A Case Report

Background: IgG4-related disease is a rare, chronic inflammatory disorder characterized by lymphoplasmacytic infiltration, 'storiform' fibrosis, and elevated IgG4 levels in affected tissues. This disease has a broad and heterogeneous clinical spectrum that includes four main phenotypes: pancreatic-hepatobiliary disease, retroperitoneal/aortic fibrosis, head and neck disease, and Mikulicz syndrome. Case Description: An 85-year-old male patient with a clinical presentation, which is unusual outside Asia, of IgG4-related disease phenotype Mikulicz syndrome, characterized by bilateral dacryoadenitis, orbital pseudotumor, and no evidence of significant systemic participation. Despite extensive involvement in the orbital and glandular region, the patient did not develop serious organ complications, a behavior rarely documented in the literature. Despite the serum IgG4 levels being normal (<135 mg/dL), the clinical and radiological picture suggested IgG4-RD, emphasizing the need for a biopsy for a definitive diagnosis. Histopathological examination revealed a dense lymphoplasmacytic infiltrate, storiform fibrosis, and more than 40% IgG4-positive cells, confirming the diagnosis. Results: Treatment with prednisone was initiated alongside azathioprine for long-term control. Calcium and vitamin D3 supplementation were added to prevent glucocorticoid-induced osteoporosis. Remarkable clinical improvement was observed within 24 h, with progressive orbital and glandular symptoms resolution. Over a year, the patient exhibited complete resolution of the orbital tumors, total recovery of vision, and no relapses. The only sequelae observed were dry eye. Conclusions: This case highlights the need to consider IgG4-RD with normal serum IgG4 levels, the importance of histopathology for diagnosis, and the efficacy of steroids as first-line treatment. A multidisciplinary approach is essential for timely treatment.

Pharmacological Management of IgG4-Related Disease: From Traditional to Mechanism-Based Targeted Therapies

IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by organ enlargement and dysfunction. The formation of tertiary lymphoid tissues (TLTs) in affected organs is crucial for understanding IgG4-RD, as T follicular helper (Tfh) 2 cells within TLTs drive IgG4+B cell differentiation, contributing to mass formation. Key cytokines IL-4 and IL-10, produced by Tfh2 cells, are essential for this process. Additionally, cytotoxic T cells and M2 macrophages significantly contribute to inflammation and fibrosis in the lesions. These insights into IgG4-RD have led to the development of innovative targeted therapies. While glucocorticoids are effective in many cases, they often cause disease flares during tapering and rarely result in long-term, treatment-free remissions. Long-term glucocorticoid use poses significant challenges owing to potential side effects, particularly in older patients who may already have complications such as diabetes and atherosclerotic diseases. In contrast, targeted therapies offer a promising alternative, potentially providing more effective disease control with fewer side effects. Current research is exploring several exciting approaches, including B-cell depletion, targeted immunomodulation of B cells, Bruton's tyrosine kinase inhibition, disruption of co-stimulation pathways, targeting the SLAMF7 cytokine or its receptor blockade (BAFF, IL-4, or IL-6), and JAK-STAT signaling pathway inhibition. These emerging strategies hold the promise of improving patient outcomes and advancing the management of IgG4-RD.

IgG4 Related Disease Presenting With Eosinophilic Pleural Effusion

A 56-year-old man presented with right-sided pleuritic chest pain and intermittent cough for 4 months, with a background history of well-controlled asthma and allergic rhinitis. Chest radiographs revealed right-sided pleural effusion, the fluid chemistry showed an exudate effusion with negative cytology and abundant eosinophils. Thoracoscopic pleural biopsy showed moderate lymphoplasmacytic chronic inflammation. Immunohistochemistry showed IgG4 staining up to 90 plasma cells/hpf (> 10% diagnostic), and the IgG4: IgG ratio was 40% (> 40% diagnostic), confirming the diagnosis of IgG4-related disease (IgG4-RD). Elevated serum IgG4 level (300 mg/dL; normal range: 3-201 mg/dL), further supported the diagnosis. While eosinophilic pleural effusion (EPE) accounts for 5%-16% of all exudative pleural effusions, IgG4-related pleural disease is an extremely rare cause of EPE.

Discriminative features of immunoglobulin G4-related disease (IgG4-RD) and associated autoimmune rheumatic diseases (ARDs) in a nationwide observational cohort: study from the Egyptian College of Rheumatology

OBJECTIVE

The objective of this study is to present the clinical characteristics of immunoglobulin G4-related diseases (IgG4-RD) patients and describe associated overlap with autoimmune rheumatic diseases (ARDs).

PATIENTS AND METHODS

This cross-sectional study included 81 patients with IgG4-RD who were recruited from 13 specialized rheumatology departments and centers across the country in collaboration with the Egyptian College of Rheumatology (ECR). Patients underwent a thorough history-taking and clinical examination. We reviewed patients' medical records and recorded the medications they used. The presence of comorbidities or cumulative manifestations was determined. Laboratory investigations, imaging, and biopsy histopathology were assessed.

RESULTS

The mean (SD) age was 41.4 (14.6) years with 60 females and 21 males (F/M 2.9:1). The diagnosis was definite in 50 (61.7%), probable in 19 (23.5%), and possible in 12 (14.8%). The most common cumulative clinical features are IgG4-related respiratory disease in 19 (23.5%), autoimmune pancreatitis (AIP) in 18 (22.2%), and Riedel's thyroiditis in 17 (21.0%). Approximately 80% were administered corticosteroids, whereas 40% received azathioprine as adjunct therapy. Approximately 16% developed a relapse with this combination and transitioned to an alternative steroid-sparing treatment. Twelve individuals (14.7%) required rituximab. Fifty percent of patients receiving rituximab (six patients) exhibited complete improvement, while the remaining had partial improvement. Ten (12.3%) patients had associated ARDs: five (6.2%) with systemic lupus erythematosus (SLE), four (4.9%) with rheumatoid arthritis (RA), and one with vasculitis. Of the four patients with associated RA, three were rheumatoid factor (RF) negative. IgG4 was in all cases, RF was positive in 18.5%, and antinuclear antibody was in 14.7%.

CONCLUSION

IgG4-RDs exhibit a wide range of presentations, closely associated with ARDs. Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis, which is essential to prevent damage to critical organs. Key Points • IgG4-RDs have a myriad spectrum of presentation with a close link to rheumatic diseases. • Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis. • The lack of reliable biomarkers for this condition has been an important hurdle for diagnosis.

Update on Autoimmune Pancreatitis and IgG4-Related Disease

Autoimmune pancreatitis is an increasingly recognized inflammatory type of subacute pancreatitis; two subtypes of autoimmune pancreatitis have been identified so far: the "lymphoplasmacytic" type 1 variant and the "neutrophilic" type 2 variant. Type 1 autoimmune pancreatitis represents the most common manifestation of IgG4-related disease, a fibro-inflammatory disorder characterized by elevated IgG4 levels in the serum and affected tissues. Type 2 autoimmune pancreatitis is a pancreas-specific disorder that frequently occurs in the context of inflammatory bowel diseases. Due to the complexity of both diseases, a comprehensive work up with imaging, laboratory, and histological studies is required to achieve a diagnosis and rule out malignancies. Glucocorticoids represent the cornerstone of the treatment, often supported by other immunosuppressive drugs in case of steroid intolerance or aggressive disease. Maintenance treatment is often employed in type 1 autoimmune pancreatitis because of the higher relapse rate compared with type 2 autoimmune pancreatitis. In this review, we summarize the key concept of autoimmune pancreatitis, delve into the differential diagnosis between the two subtypes, and cover the recent relevant research findings and pressing unmet needs.

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

PURPOSE

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

METHODS

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

DISCUSSION

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

CONCLUSIONS

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

Clinical and Radiologic Differences in Lung Involvement Between IgG4-Related Disease and Plasma Cell-Type Idiopathic Multicentric Castleman Disease

PURPOSES

Immunoglobulin G4-related disease (IgG4-RD) and plasma cell-type idiopathic multicentric Castleman disease (PC-iMCD) have many overlapping features. Their differential diagnosis is challenging and crucial for clinical management due to their different prognoses and treatments. However, reports that compare these conditions are scarce, especially for patients with lung involvement. In this study, we attempted to clarify the clinical and radiologic differences in lung involvement between IgG4-RD and PC-iMCD.

METHODS

Patients with IgG4-RD or PC-iMCD who exhibited lung involvement were enrolled. Clinical and chest CT findings at baseline were compared.

RESULTS

A total of 178 patients with IgG4-RD and 61 patients with PC-iMCD exhibited lung involvement. The IgG4-RD group consisted of older patients (P < 0.001) and had a higher male‒female ratio (P = 0.004). Patients with PC-iMCD were more inclined to present constitutional and respiratory symptoms, anemia, thrombocytosis and hypoalbuminemia (all P < 0.001). Although IgG4 levels were commonly elevated in both diseases, they were significantly greater in the IgG4-RD (median: 16,100 mg/L) than in the PC-iMCD (median: 3130 mg/L) (P < 0.001). Patients with IgG4-RD showed significantly lower levels of IgG, IgA, IgM (median: 21.59 g/L, 1.70 g/L, and 0.68 g/L, respectively) than in the PC-iMCD (median: 34.42 g/L, 4.85 g/L, and 2.11 g/L, respectively) (all P < 0.001). The levels of CRP, ESR and IL-6 were significantly greater in the PC-iMCD (median: 72.15 mg/L, 103 mm/h, and 18.30 pg/mL, respectively) than that in the IgG4-RD (median: 1.54 mg/L, 22 mm/h, and 2.85 pg/mL, respectively) (all P < 0.001). Although both nodular lesions and thickened bronchovascular bundles were common in these two diseases, PC-iMCD patients presented more extensive nodular lesions (P < 0.001), and IgG4-RD patients presented more diffuse thickened bronchovascular bundles (P < 0.001). Cysts were almost exclusively observed in PC-iMCD patients.

CONCLUSIONS

Compared with IgG4-RD, PC-iMCD is a more aggressive condition, associated with more common symptoms and more severe inflammation. Radiologically, extensive nodular lesions or cysts suggest a diagnosis of PC-iMCD, whereas diffuse thickened bronchovascular bundles indicate a diagnosis of IgG4-RD.

IgG4-related retroperitoneal fibrosis presenting as a peripancreatic mass: a case series

Introduction

IgG4-related disease (IgG4-RD) is a chronic, immune-mediated disorder characterized by widespread inflammation and fibrosis, leading to potential organ dysfunction if untreated. Often underdiagnosed due to subtle and varied symptoms, the disease can affect multiple organ systems. This case series highlights two patients who were diagnosed as cases of IgG4-related retroperitoneal fibrosis.

Methods

A total of two patients were included in this prospective case series who presented to the gastroenterology department of a tertiary care hospital with the same signs and symptoms and were diagnosed with IgG4-related retroperitoneal fibrosis (IgG4-RPF).

Case summary

Two patients were included in our case series, aged 25 and 26 years. The chief complaints included dull, radiating epigastric pain, other symptoms include diffuse abdominal pain, intensified, accompanied by nausea, vomiting, and episodic diarrhea, and a history of B-cell lymphoproliferative disorder. Endoscopic ultrasound (EUS)-)-guided biopsies were performed, showing findings consistent with (IgG4-RPF). Both patients were started on a regimen of prednisolone, pantoprazole, and vitamin D, which they tolerated well without adverse effects. They were advised to follow up with a CT scan after one month.

Conclusion

IgG4-related disease (IgG4-RD) is a rare, chronic condition often presenting as retroperitoneal fibrosis (RPF) and affecting multiple organs. Serum IgG4 levels can be normal in certain cases, histopathological and radiological investigations are necessary for the correct diagnosis. Early initiation of immunosuppressive drugs are necessary for the disease control.

IgG4-related Disease: Recent Topics on Immunological Aspects of This Disorder and Their Application in New Treatment Strategies

IgG4-related disease (IgG4-RD) is a systemic and chronic inflammatory disorder that can affect every part of the body. The formation of tertiary lymphoid tissues (TLT) in the affected organs may be a key phenomenon in understanding the pathogenesis of this disease because T follicular helper (Tfh) 2 cells play an important role in IgG4 class switching within TLT in the affected organs or tissues. TLT formation leads to the formation of masses or swelling of the affected organs. Interleukin (IL)-4 and IL-10 are critical cytokines for IgG4-class switching and are produced in TLT. Other factors, such as CD4-positive (CD4+) cytotoxic T cells, M2 macrophages, and LAG3+ Tfh cells, have been identified as disease-specific contributors to lesion formation. In this review, I describe the current knowledge necessary to understand the pathogenesis of this disease and recent developments in treatment strategies beyond B-cell depletion therapy.

Successful rituximab treatment in IgG4-related coronary periarteritis: a case-based review

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated disorder characterized by elevated serum IgG4 levels and the enlargement and fibrosis of organs. As a rare manifestation, coronary arteries can be affected by IgG4-RD as coronary periarteritis, leading to serious complications such as stenosis or aneurysm. Although coronary periarteritis poses a life-threatening condition, optimal treatment strategies remain unclear due to its extreme rarity. While glucocorticoids have shown efficacy in several reported cases of IgG4-related coronary periarteritis, many cases experience relapse during glucocorticoid tapering. Furthermore, long-term use of glucocorticoids promotes atherosclerosis and increases the risk of major adverse cardiovascular events. Given that rituximab has been reported to be effective in treating IgG4-RD, it may be a potential treatment option for this condition. We present a case of IgG4-related coronary periarteritis, in which the patient achieved and maintained remission with rituximab. Furthermore, our review of the literature identified 17 cases of IgG4-related coronary periarteritis, all of which were successfully treated with rituximab. These findings suggest that rituximab serves as a viable option for both induction and maintenance therapy in IgG4-related coronary periarteritis.

Immunoglobulin G4-related disease of the testis masquerading as a testicular mass: a clinical dilemma

Immunoglobulin G4 (IgG4)-related disease is a rare immune-mediated fibro-inflammatory disorder with many clinical manifestations. Most commonly affected sites include the pancreas, salivary glands, kidneys, lachrymal glands, biliary tree, aorta and retroperitoneum; testicular involvement is a rare entity. This report describes a man in his 20s who presented with a persistent painless mass in his left testis. After a thorough examination he underwent orchiectomy to rule out any malignancy of the testis. Histopathology and immunohistochemistry were suggestive of IgG4-related disease. Systemic evaluation showed normal IgG4 levels with no other site of involvement. This is a unique presentation of this rare diagnosis and remains a diagnostic challenge which is difficult to distinguish from the more common testicular malignancy. We conducted a review of the current literature regarding IgG4-related disease to complement the case discussion and provide a comprehensive review regarding this diagnostic dilemma.

An Unusual Case of Overlapping Immunoglobulin G4-Related Disease and Systemic Lupus Erythematosus

Immunoglobulin G4-related disease (IgG4-RD) and systemic lupus erythematosus (SLE) are multisystemic autoimmune disorders that can present with renal manifestations. Overlapping cases of these diseases are extremely rare and present both diagnostic and therapeutic challenges. We report the case of a 70-year-old male with a history of autoimmune pancreatitis, who was admitted with fatigue, weight loss, and worsening kidney function. Laboratory tests revealed anemia with a positive Coombs test, leucopenia, elevated IgG4, hypocomplementemia, and positive results for ANA, anti-double-stranded DNA (dsDNA), anti-nucleosome, anti-RP11 antibodies, and rheumatoid factor. A spot urine sample showed subnephrotic proteinuria without hematuria. The patient met the criteria for both SLE and possible IgG4-RD, but the cause of the worsening renal function remained unclear, prompting a kidney biopsy. The biopsy revealed a lymphoplasmacytic infiltrate, storiform fibrosis, and IgG4-positive staining, consistent with IgG4-related tubulointerstitial nephritis, but without evidence of lupus nephritis. The patient was treated with prednisolone, resulting in improvement of both his symptoms and kidney function. However, significant leukopenia, anemia, and elevated anti-dsDNA titers persisted, which were presumed to be secondary to the overlapping SLE. Hydroxychloroquine and azathioprine were added to the treatment regimen, leading to improvement in cytopenias at the three-month follow-up. This case underscores the importance of kidney biopsy in suspected overlapping autoimmune diseases for identifying kidney involvement and guiding treatment, although evidence regarding optimal therapy remains limited.

An Unusual Case of Chylous Ascites

Chylous ascites occur when the lymphatic flow is blocked or disrupted, causing a leakage of fluid into the peritoneal space. It can be caused by a number of etiologies and identifying the exact cause can be challenging. We present the case of a 77-year-old man who presented with chylous ascites. An abdominal computed tomography scan revealed an abnormal spiculated mass and lymph nodes in the central mesentery encasing the pancreas, raising suspicion of pancreatic malignancy. A subsequent mesenteric biopsy indicated sclerosing mesenteritis characterized by dense fibrous tissue and positive Immunoglobulin G4 (IgG4) staining, leading to a final diagnosis of IgG4-related disease (IgG4-RD). The patient responded positively to a treatment regimen that included systemic steroids and rituximab. This case, with its atypical presentation of IgG4-RD, contributes to our understanding of this rare disease, providing valuable insights for future diagnosis and treatment.

IgG4-related disease mimicking a liver abscess

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

Immunoglobulin G4-related spinal pachymeningitis: A case report

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a complex immune-mediated condition that causes fibrotic inflammation in several organs. A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis, which manifests as inflammation of the dura mater in intracranial or spinal regions. Although IgG4-RD can affect multiple areas, the spine is a relatively rare site compared to the more frequent involvement of intracranial structures.

CASE SUMMARY

A 70-year-old male presented to our hospital with a two-day history of fever, altered mental status, and generalized weakness. The initial brain magnetic resonance imaging (MRI) revealed multiple small infarcts across various cerebral regions. On the second day after admission, a physical examination revealed motor weakness in both lower extremities and diminished sensation in the right lower extremity. Electromyographic evaluation revealed findings consistent with acute motor sensory neuropathy. Despite initial management with intravenous immunoglobulin for presumed Guillain-Barré syndrome, the patient exhibited progressive worsening of motor deficits. On the 45th day of hospitalization, an enhanced MRI of the entire spine, focusing specifically on the thoracic 9 to lumbar 1 vertebral level, raised the suspicion of IgG4-related spinal pachymeningitis. Subsequently, the patient was administered oral prednisolone and participated in a comprehensive rehabilitation program that included gait training and lower extremity strengthening exercises.

CONCLUSION

IgG4-related spinal pachymeningitis, diagnosed on MRI, was treated with corticosteroids and a structured rehabilitation regimen, leading to significant improvement.

A Review of IgG4-related Sclerosing Cholangitis (IgG4-SC)

IgG4-related sclerosing cholangitis (IgG4-SC) is a unique, steroid-responsive, fibroinflammatory condition that is more commonly found in older men and is strongly associated with autoimmune pancreatitis (AIP). It may pose a diagnostic challenge at times due to closely mimicking hepatobiliary diseases such as primary sclerosing cholangitis (PSC), secondary sclerosing cholangitis (SSC), and cholangiocarcinoma. IgG4-SC has an excellent prognosis when promptly diagnosed and treated with steroids. Literature search strategy: The authors searched PubMed and Google Scholar, for articles with the search terms "autoimmune cholangiopathy" and "IgG4 cholangiopathy."

Aortoduodenal Fistula With IgG4-Related Periaortitis: A Case Report

A 77-year-old woman with a history of endovascular aneurysm repair (EVAR) for an abdominal aortic aneurysm (AAA) presented with melena. She had been recently diagnosed with IgG4-related periaortitis and started on prednisone. Physical examination revealed pallor conjunctiva and melena on the rectal examination, with laboratory results indicating anemia (hemoglobin: 7.4 g/dl). Abdominal CT showed air within the aneurysmal sac, and endoscopy confirmed an aortoduodenal fistula. The patient underwent urgent stent removal, vessel replacement, and duodenal repair. She recovered well and was discharged on day 30 with ongoing prednisone therapy. The risk of fistula formation in IgG4-related periaortitis necessitates careful monitoring, especially in patients with pre-existing aortic pathology.

IgG4-related Breast Disease: Review of the Literature

IgG4-related disease (IgG4-RD) is a rare illness with inflammatory and fibrotic changes in affected organs such as pancreas, thyroid, salivary or lacrimal glands, and retroperitoneal space; rarely other organs may be involved. IgG4-related breast disease (IgG4-BD) is very rare and generally presents as a lump or mastitis. IgG4-BD as a presenting feature of IgG4-RD is extremely rare. Hence, this paper reviews the known (n=48) IgG-BD cases reported in the literature to date. The majority of cases were diagnosed on routine mammography or during assessment for other clinically significant features. The absence of a lump border, and especially the absence of calcifications on ultrasonography, mammography, or computed tomography, is typical for IgG4-BD. Characteristic IgG4-BD pathological findings were dense lymphoplasmacytic infiltration with stromal fibrosis, and more than 10% IgG4+ plasma cells/high-power field (HPF); the mean percentage of IgG4+/IgG+ plasma cells was 54.2%, and only one-third of the patients had all "classical" signs of IgG4-BD including storiform fibrosis and obliterative phlebitis. Most of the cases had a benign course and responded to surgical excision with or without steroid therapy.

Omics in IgG4-related disease

ABSTRACT

Research on IgG4-related disease (IgG4-RD), an autoimmune condition recognized to be a unique disease entity only two decades ago, has processed from describing patients' symptoms and signs to summarizing its critical pathological features, and further to investigating key pathogenic mechanisms. Challenges in gaining a better understanding of the disease, however, stem from its relative rarity-potentially attributed to underrecognition - and the absence of ideal experimental animal models. Recently, with the development of various high-throughput techniques, "omics" studies at different levels (particularly the single-cell omics) have shown promise in providing detailed molecular features of IgG4-RD. While, the application of omics approaches in IgG4-RD is still at an early stage. In this paper, we review the current progress of omics research in IgG4-RD and discuss the value of machine learning methods in analyzing the data with high dimensionality.

IgG4-Related Disease Involving the Ear: A Case Report

IgG4-related disease is a chronic inflammatory disease with widespread clinical presentation. It mimics various malignant, infectious, and inflammatory conditions, leading to confusion in diagnosis and management. Otological manifestations, though relatively rare, can lead to significant complications. A 45-year-old male with a recent history of ventilation tube placement in the right ear presented with a sensation of imbalance associated with profound hearing loss. He was managed in line of acute otitis media with labyrinthitis with steroids and antibiotics and removal of the ventilation tube. He returned in one week and presented with right-sided lower motor neuron-type facial paresis. Computed tomography images of the temporal bone showed a soft tissue density lesion in the right middle ear cavity extending to the mastoid antrum. He underwent a right cortical mastoidectomy with decompression of the facial nerve. Histopathology and immunohistochemistry of granulation tissues from the middle ear and the mastoid revealed evidence suggestive of probable IgG4 disease. IgG4-related disease is a relatively new entity, and its pathogenesis has not been properly understood. IgG4 subclass has been involved in this disease resulting in fibro-inflammatory conditions leading to tumor-like masses or fibrosis of the affected organs. Treatment includes glucocorticoids and immunosuppressant medications.

New insights into predictors of autoimmune pancreatitis relapse after steroid therapy

OBJECTIVES

While autoimmune pancreatitis (AIP) responds well to steroid therapy, the high relapse rate in type 1 AIP remains a critical problem. The present study examined predictors of relapse of type 1 AIP following steroid therapy.

MATERIALS AND METHODS

Nine factors potentially predictive of relapse were analyzed in 81 AIP patients receiving steroid therapy with follow-up ≥ 12 months. The rate of serum IgG4 decrease following steroid therapy was calculated by dividing the difference between serum IgG4 values before and at two months after the start of steroid by the IgG4 value before steroid.

RESULTS

A relapse occurred in 11 patients (13.5%) during a median of 38 months. Multivariate analysis revealed that the presence of IgG4-related retroperitoneal fibrosis (HR: 5.59; 95% CI: 1.42-22.0; p = 0.014) and the low rate of serum IgG4 decrease after steroid therapy (HR: 0.048; 95% CI: 0.005-0.46; p = 0.008) were significant, independent predictors of AIP relapse. The cut-off value based on receiver operating characteristic curve data for the rate of serum IgG4 decrease before and at two months after steroid therapy distinguishing patients with and without a relapse was 0.65. Using this cut-off value, the area under the curve, sensitivity, and specificity were found to be 0.63, 0.73, and 0.60, respectively.

CONCLUSION

The low rate of serum IgG4 decrease after the start of steroid therapy and the presence of IgG4-related retroperitoneal fibrosis were predictive of type 1 AIP relapse. Cautious, gradual tapering of steroid dosage and longer maintenance therapy are recommended for patients with these factors.

IgG4-related disease: Effectiveness evaluation through Umehara-Okazaki 2011 and ACR/EULAR 2019 diagnostic criteria

BACKGROUND

IgG4-related disease (IgG4-RD) is a rare, systemic immune-mediated fibro-inflammatory condition with an unclear etiology and pathophysiology, potentially affecting multiple organs. It presents with common clinical, radiological, and serological characteristics. This study aims to compare the latest two IgG4-RD classification and diagnostic criteria: Umehara-Okazaki 2011 and ACR/EULAR 2019.

MATERIAL AND METHODS

In a retrospective cross-sectional study conducted across two centers from January 2010 to July 2023, we included patients suspected of having IgG4-RD from various hospital departments. Patients finally diagnosed with other pathologies were excluded. The remaining suspected IgG4-RD cases were evaluated using both Umehara-Okazaki 2011 and ACR/EULAR 2019 criteria.

RESULTS

Out of 34 patients with a clinical diagnosis of IgG4-RD, the Umehara-Okazaki 2011 classified 20 patients: 5 as definitive, 7 as probable, and 8 as possible cases. Applying the ACR/EULAR 2019 criteria to the same cohort resulted in the diagnosis of 9 patients. Notably, retroperitoneal fibrosis and aortitis were the most prevalent form of presentation, accounting for 25% and 22.2% of cases classified under the 2011 and 2019 criteria, respectively.

DISCUSSION

The more recent and stringent ACR/EULAR 2019 criteria focus on histopathology, various forms of presentation, and analytical data, allow for a more accurate classification of patients.

Coronary Artery Aneurysm or Ectasia as a Form of Coronary Artery Remodeling: Etiology, Pathogenesis, Diagnostics, Complications, and Treatment

Coronary artery aneurysm or ectasia (CAAE) is a term that includes both coronary artery ectasia (CAE) and coronary artery aneurysm (CAA), despite distinct phenotypes and definitions. This anomaly can be found in 0.15-5.3% of coronary angiography. CAE is a diffuse dilatation of the coronary artery at least 1.5 times wider than the diameter of the normal coronary artery in a patient with a length of over 20 mm or greater than one-third of the vessel. CAE can be further subdivided into diffuse and focal dilations by the number and the length of the dilated vessels. Histologically, it presents with extensive destruction of musculoelastic elements, marked degradation of collagen and elastic fibers, and disruption of the elastic lamina. Conversely, CAA is a focal lesion manifesting as focal dilatation, which can be fusiform (if the longitudinal diameter is greater than the transverse) or saccular (if the longitudinal diameter is smaller than the transverse). Giant CAA is defined as a 4-fold enlargement of the vessel diameter and is observed in only 0.02% of patients after coronary. An aneurysmal lesion can be either single or multiple. It can be either a congenital or acquired phenomenon. The pathophysiological mechanisms responsible for the formation of CAAE are not well understood. Atherosclerosis is the most common etiology of CAAE in adults, while Kawasaki disease is the most common in children. Other etiological factors include systemic connective tissue diseases, infectious diseases, vasculitis, congenital anomalies, genetic factors, and idiopathic CAA. Invasive assessment of CAAE is based on coronary angiography. Coronary computed tomography (CT) is a noninvasive method that enables accurate evaluation of aneurysm size and location. The most common complications are coronary spasm, local thrombosis, distal embolization, coronary artery rupture, and compression of adjacent structures by giant coronary aneurysms. The approach to each patient with CAAE should depend on the severity of symptoms, anatomical structure, size, and location of the aneurysm. Treatment methods should be carefully considered to avoid possible complications of CAAE. Simultaneously, we should not unnecessarily expose the patient to the risk of intervention or surgical treatment. Patients can be offered conservative or invasive treatment. However, there are still numerous controversies and ambiguities regarding the etiology, prognosis, and treatment of patients with coronary artery aneurysms. This study summarizes the current knowledge about this disease's etiology, pathogenesis, and management.

The clinical outcomes and healthcare resource utilization in IgG4-related disease: a claims-based analysis of commercially insured adults in the United States

OBJECTIVES

IgG4-related disease (IgG4-RD) can affect nearly any organ and is often treated with glucocorticoids, which contribute to organ damage and toxicity. Comorbidities and healthcare utilization in IgG4-RD are poorly understood.

METHODS

We conducted a cohort study using claims data from a US managed care organization. Incident IgG4-RD cases were identified using a validated algorithm; general population comparators were matched by age, sex, race/ethnicity and index date. The frequency of 21 expert-defined clinical outcomes associated with IgG4-RD or its treatment and healthcare-associated visits and costs were assessed 12 months before and 36 months after the index date (date of earliest IgG4-RD-related claim).

RESULTS

There were 524 cases and 5240 comparators. Most cases received glucocorticoids prior to (64.0%) and after (85.1%) the index date. Nearly all outcomes, many being common glucocorticoid toxicities, occurred more frequently in cases vs comparators. During follow-up, the largest differences between cases and comparators were seen for gastroesophageal reflux disease (prevalence difference: +31.2%, P < 0.001), infections (+17.3%, P < 0.001), hypertension (+15.5%, P < 0.01) and diabetes mellitus (+15.0%, P < 0.001). The difference in malignancy increased during follow-up from +8.8% to +12.5% (P < 0.001). Some 17.4% of cases used pancreatic enzyme replacement therapy during follow-up. Over follow-up, cases were more often hospitalized (57.3% vs 17.2%, P < 0.01) and/or had an emergency room visit (72.0% vs 36.7%, P < 0.01); all costs were greater in cases than comparators.

CONCLUSIONS

Patients with IgG4-RD are disproportionately affected by adverse outcomes, some of which may be preventable or modifiable with vigilant clinician monitoring. Glucocorticoid-sparing treatments may improve these outcomes.

Advances in understanding and management of IgG4-related ophthalmic disease

Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) is an emerging, immune-mediated fibroinflammatory orbital disease, characterized by tumefactive lesions with noticeable IgG4+ plasma cell infiltration and distinctive pathohistological features. This disease is often associated with elevated serum IgG4 concentrations. IgG4-ROD may affect any ophthalmic tissues, particularly the lacrimal gland, extraocular muscles, and trigeminal nerves. Although the exact pathogenic role of IgG4 antibodies remains unclear, B-cell depleting agents have been reported to be an effective treatment. The diverse clinical manifestations of IgG4-ROD complicate diagnosis, and without prompt treatment, visual-threatening complications such as optic neuropathy may arise. Recent advances in understanding and managing IgG4-ROD have revolutionized the diagnosis and treatment of this emerging disease. This review article aims to provide a comprehensive overview of the latest advancements in the field of IgG4-ROD.

Efficacy and safety of rituximab induction therapy and effect of rituximab maintenance for IgG4-related disease: a systematic review and meta-analysis

BACKGROUND

Previous studies have reported that rituximab (RTX) therapy might be beneficial in reducing relapse rates in patients with IgG4-related disease (IgG4-RD). Therefore, we aimed to systematically assess the efficacy and safety of RTX induction treatment and the effect of RTX maintenance in patients with IgG4-RD.

METHODS

The protocol was registered in the PROSPERO (CRD42023427352). PubMed, Embase, the Cochrane database, Scopus, and the Web of Science were interrogated to identify studies that evaluated the impact of RTX on prognosis in IgG4-RD. We explored the impact of various subgroups of factors on relapse outcomes and focused on the possible role of maintenance therapy in reducing relapse rates. The pooled incidence of adverse events of RTX therapy and the influencing factors have also been evaluated.

RESULTS

Eighteen studies comprising 374 patients (mean age 56.0 ± 8.7 years; male 73.7 %) with a mean follow-up duration of 23.4 ± 16.3 months were included. The pooled estimate of the response rate, complete remission rate, overall relapse rate, adverse event rate, and serious adverse event rate of RTX induction therapy were 97.3 % (95 % CI, 94.7 %-99.1 %), 55.8 % (95 % CI, 39.6 %-71.3 %), 16.9 % (95 % CI, 8.7 %-27.1 %), 31.6 % (95 % CI, 16.7 %-48.9 %) and 3.9 % (95 % CI, 0.8 %-8.9 %), respectively. In subgroup analysis, the pooled relapse rate was significantly lower in studies with maintenance than without maintenance (2.8% vs 21.5 %, p < 0.01). Pooled Kaplan-Meier relapse curves also demonstrated that RTX maintenance therapy provided a better prognosis.

CONCLUSIONS

RTX induction therapy appears to have satisfactory efficacy in the induction of remission in IgG4-RD. In addition, prophylactic RTX maintenance therapy after induction may be beneficial in preventing relapse of IgG4-RD.

Assessing IgG4-related ophthalmic disease and its mimics: a comparison of ACR/EULAR, organ-specific and revised comprehensive diagnostic criteria

AIMS

Diagnosis of IgG4-related ophthalmic disease (IgG4-ROD) rests on the correlation of clinical features, serological testing and histopathology, using internationally accepted diagnostic criteria for objective interpretation; however, several mimickers of IgG4-RD overlap in clinical presentation and histopathology. We assess histopathological features in a series of presumptive IgG4-ROD cases, with emphasis on histopathological mimics and comparison of three IgG4-ROD diagnostic/classification criteria (organ-specific (OS), revised comprehensive diagnostic (RCD) and American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) criteria).

METHODS

The histopathology database was screened for cases with clinical/histopathological suspicion of IgG4-ROD. Slides were reviewed, OS, RCD and ACR/EULAR criteria were applied, and the final clinicopathological diagnosis was recorded.

RESULTS

37 patients (24 females, 13 males; 19-73 years) were diagnosed as either IgG4-ROD (n=18) or non-IgG4-related disease (n=19). Non-IgG4-related disease group showed elevated serum IgG4 (55.5%), fibrosis (100%), dense lymphoplasmacytic inflammation (92.8%), with an increase in tissue IgG4+plasma cells (57.1%) and elevated IgG4:IgG+plasma cell ratio (14.3%). ACR/EULAR missed 50% (9/18, sensitivity-52.8%) of true IgG4-ROD cases, while OS and RCD criteria missed 11.1% (2/18, sensitivity-88.9%) of IgG-ROD cases. ACR/EULAR criteria mislabelled 7.14% (1/14, specificity-90.9%) while OS and RCD criteria wrongly categorised 71.4% (10/14, specificity-47.4%) and 50% (7/14, specificity-63.2%) specific non-IgG4-ROD cases as IgG4-ROD. Storiform fibrosis, obliterative phlebitis, increased IgG4:IgG+plasma cell ratio and elevated serum IgG were statistically significant in distinguishing IgG4-ROD from its mimics.

CONCLUSION

ACR/EULAR criteria showed high specificity but were cumbersome and sensitivity was low, while RCD and OS criteria showed low specificity. Stringent clinicopathological correlation to exclude mimics is critical in avoiding diagnostic errors in IgG4-ROD.

Sino-Orbital IgG4 Related Disease- An Uncommon Entity

IgG4 related disease (IgG4-RD) is an auto immune fibro-inflammatory condition, characterised by presence of IgG4 positive lymphoplasmacytic infiltrates and extensive fibrosis of the involved organ. It commonly affects pancreas, biliary tract and salivary glands. Sino-orbital involvement is a relatively rare presentation. There is extensive fibrosis of the involved organ. Biopsy is often diagnostic and it shows extensive necrosis and lymphoplasmocytic infiltrates. They show dramatic response to steroid therapy. Here we present three cases of IgG4-RD disease involving orbit and para nasal sinuses who were evaluated and treated in a tertiary care teaching hospital over a period of 2 years.