Current status of type 1 (IgG4-related) autoimmune pancreatitis

Defining pancreatic damage and symptom burden in IgG4-related autoimmune pancreatitis: A cross-sectional study of 118 patients from a single-center registry

OBJECTIVES

Type 1 autoimmune pancreatitis is a common manifestation of IgG4-related disease (IgG4-RD). However, there is a paucity of literature characterizing pancreatic damage and symptom burden in IgG4-RD.

METHODS

We performed a cross-sectional analysis of patients who fulfilled the ACR/EULAR IgG4-RD Classification Criteria. Disease features and complications were collected by medical record review. A survey regarding symptoms and disease history was distributed to all patients. Characteristics were compared between patients with and without autoimmune pancreatitis.

RESULTS

Of 303 patients who fulfilled Classification Criteria at the time of the chart review, 118 (39 %) had evidence of autoimmune pancreatitis. Overt indicators of acute pancreatitis (e.g., abdominal pain, nausea/emesis, elevated serum lipase) each occurred in fewer than 50 % of patients with autoimmune pancreatitis. Diabetes mellitus (DM), exocrine pancreatic insufficiency (EPI), or both were present in 47 %, 48 %, and 21 % of the autoimmune pancreatitis patients, respectively. After encouraging all patients to have fecal elastase measured, 40/49 (82 %) stool samples had low elastase concentrations. 9/118 (8 %) had undergone pancreatic resections before the diagnosis was established. 162/325 (50 %) completed surveys (n = 81 [50 %] with autoimmune pancreatitis). Patients with autoimmune pancreatitis reported a higher burden of abdominal pain, weight loss, and changes in stool than those without (all p < 0.05).

CONCLUSION

Despite an often subclinical presentation, autoimmune pancreatitis is associated with EPI, DM, or both in a high percentage of patients with IgG4-RD. While symptomatic acute pancreatitis may not be common, patient-reported symptom burden due to IgG4-related autoimmune pancreatitis or its complications is greater than previously appreciated.

'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.

A case of PLA2R-positive membranous nephropathy with subsequent development of IgG4-related disease

Membranous nephropathy (MN) is a common cause of adult-onset nephrotic syndrome. It is also known as a minor but established renal manifestation of Immunoglobulin G4-related disease (IgG4-RD). Previous reports suggest that MN can also be an initial manifestation of IgG4-RD, all of which are phospholipase A2 receptor (PLA2R)-negative MN. We describe a case of PLA2R-positive MN that subsequently developed other manifestations of IgG4-RD. A 60-year-old male with nephrotic syndrome was diagnosed as primary MN with positive staining for PLA2R on the initial renal biopsy, which remained in partial remission with supportive therapy using angiotensin II receptor blocker (ARB) without steroid. About 1 year later, a renal mass was detected during an annual checkup, and contrast-enhanced computed tomography revealed low-density masses in bilateral kidneys and the head of the pancreas. The findings of endoscopic biopsy of the pancreatic mass were consistent with autoimmune pancreatitis (AIP) and the second renal biopsy showed the findings of MN with tubulointerstitial nephritis, both of which led to a diagnosis of IgG4-RD. The second renal biopsy also showed positive PLA2R. The patient received oral glucocorticoid therapy for IgG4-RD, which improved IgG4-related AIP and renal masses and also resulted in complete remission of MN. To our knowledge, this is the first reported case of PLA2R-positive MN with subsequent development of IgG4-RD. It is sometimes difficult to determine whether PLA2R-positive MN occurring with IgG4-RD is primary MN or secondary MN associated with IgG4-RD. The possibility of developing IgG4-RD should be considered even when preceding MN is PLA2R-positive, suggesting of primary MN.

Unraveling the Microenvironment and the Pathogenic Axis of HIF-1α-Visfatin-Fibrosis in Autoimmune Pancreatitis Using a Single-Cell Atlas

Autoimmune pancreatitis (AIP) is identified as a severe chronic immune-related disorder in pancreas, including two subtypes. In this study, pancreatic lesions in patients diagnosed as either type 1 AIP or type 2 AIP are examined, and these patients' peripheral blood at single-cell level. Furthermore, flow cytometry, immunofluorescence, and functional assays are performed to verify the identified cell subtypes. In type 1 AIP, there is a notable increase in the amount of B cells and plasma cells, and IgG4+ plasma cells are key pathogenic cells of AIP. The differentiation path of naïve-stage B cells into IgG4+ produced plasma cells is observed, and an increased amount of T helper cells and T follicular helper (Tfh) cells. This study also reveals that HIF-1α, an activated transcriptional factor, can directly bind to promoter site of NAMPT, promoting higher levels of visfatin production in HIF1A+ classical monocytes. Pancreatic stellate cells can be activated by extracellular visfatin and promote the development of fibrotic response in pancreatic lesions across both AIP subtypes. The current findings shed light on the exploration of dynamic alterations in peripheral blood cells and cell subgroups in pancreatic lesions of AIP, while elucidating a pathogenic cell subset and potential fibrosis mechanism of AIP.

A Rare Case of Autoimmune Pancreatitis in a 9-Year-Old Male Patient: A Comprehensive Diagnosis and Successful Treatment

Autoimmune pancreatitis (AIP) is a rare and complex condition that can be difficult to identify due to its resemblance to malignancies. This case report presents a unique instance of AIP in a 9-year-old male patient who presented with painless jaundice and elevated liver function test results. His symptoms were persistent even after previous common bile duct stent placement, requiring additional investigation. The possibility of AIP was raised by further serological tests and imaging examinations. The diagnosis was then confirmed by multiple characteristic findings revealed through history, imaging, clinical examination, histology, and lab results. Treatment was initiated with corticosteroids, which resulted in a complete resolution of symptoms and remarkable recovery. This case emphasizes the significance of including AIP in the differential diagnosis of pancreatic disorders, even in pediatric patients.

Clinical characteristics, imaging diagnostic accuracy, and prognosis of autoimmune pancreatitis: A real-world study in China

OBJECTIVE

In this study we aimed to comprehensively evaluate the clinical features and treatment outcomes of Chinese patients with autoimmune pancreatitis (AIP) through a single-center real-world study.

METHODS

Patients diagnosed with AIP in Changhai Hospital, Naval Medical University from January 2014 to December 2021 were included. Baseline characteristics, laboratory test results, cross-sectional imaging and endoscopic ultrasound (EUS) findings, and long-term follow-up data were obtained. The differences in these characteristics between type 1 and type 2 AIP patients were analyzed.

RESULTS

Among all 320 patients, 271 (84.7%) and 49 (15.3%) had type 1 and type 2 AIP, respectively. The most common initial symptom was abdominal discomfort (58.1%), followed by obstructive jaundice (32.5%). Extrapancreatic organ involvement was identified in 126 (39.4%) patients, with the biliary system being the most commonly involved (36.6%). Elevated serum IgG4 level was rare in type 2 AIP patients. The diagnostic accuracy of computed tomography (CT), magnetic resonance imaging (MRI), and EUS for definitive and probable AIP were 78.0%, 68.7%, and 80.5%, respectively. EUS-guided tissue acquisition with immunohistochemical staining helped establish a final diagnosis in 39.7% of patients. During the follow-up period of 60 months, 18.6% of patients experienced relapse. The 1-, 3-, and 5-year relapse rates were higher in type 1 AIP patients, with an accumulated rate of 8.0%, 12.6%, and 15.1%, when compared with those with type 2 AIP.

CONCLUSIONS

Type 2 AIP is not uncommon in Chinese population. The diagnostic accuracy of CT and EUS for AIP might be superior to that of MRI.

IgG4-Related Autoimmune Pancreatitis Mimicking Pancreatic Cancer: A Report of Two Cases

IgG4-related autoimmune pancreatitis (AIP) is a rare inflammatory condition characterized by elevated IgG4-positive plasma cells and lymphoplasmacytic infiltration in the pancreas. This disease responds to steroid therapy but can be challenging to differentiate from pancreatic cancer. In this paper, we present two cases of IgG4-related AIP presenting as pancreatic masses. Our aim is to highlight the diagnostic complexities of this condition and emphasize the need for a multidisciplinary approach to avoid unnecessary surgical interventions and ensure appropriate treatment.

Recent advances in IgG4-related autoimmune pancreatitis

The incidence of IgG4-related autoimmune pancreatitis (IgG4-AIP) is high in Asia and other countries, and unnecessary treatment is often undertaken due to both missed diagnosis and misdiagnosis in clinical practice. Although IgG4-AIP has attracted increasing attention, the details of IgG4-AIP pathogenesis and systemic immune response, including its relationship to tumor pathogenesis, are still unclear. In recent years, research on serum immunological detection, pathological features, clinical manifestations, diagnosis and treatment measures for IgG4-AIP has gradually increased. It is of great importance to summarize and discuss the latest progress regarding IgG4-AIP disease.

Understanding autoimmune pancreatitis: Clinical features, management challenges, and association with malignancies

In this editorial we comment on the article by Jaber et al. Autoimmune pancreatitis (AIP) represents a distinct form of pancreatitis, categorized into AIP-1 and AIP-2, characterized by obstructive jaundice, lymphoplasmacytic infiltrate, and fibrosis. AIP-1, associated with elevated immunoglobulin G4 (IgG4) levels, exhibits higher relapse rates, affecting older males, while AIP-2 is less common and linked to inflammatory bowel disease. AIP is considered a manifestation of IgG4-related systemic disease, sharing characteristic histological findings. Steroids are the primary treatment, with emerging biomarkers like interferon alpha and interleukin-33. AIP poses an increased risk of various malignancies, and the association with pancreatic cancer is debated. Surgery is reserved for severe cases, necessitating careful evaluation due to diagnostic challenges. AIP patients may have concurrent PanINs but display favorable long-term outcomes compared to pancreatic cancer patients. Thorough diagnostic assessment, including biopsy and steroid response, is crucial for informed surgical decisions in AIP.

IgG4-related pancreatobiliary diseases could be associated with onset of pancreatobiliary cancer: A multicenter cohort study

BACKGROUND

The risk and prognosis of pancreatobiliary cancer and in patients with autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC) remain unclear. Therefore, we retrospectively investigated the risk of pancreatobiliary cancer and prognosis in patients with AIP and IgG4-SC.

METHODS

Patients with AIP and IgG4-SC at seven centers between 1998 and 2022 were investigated. The following data were evaluated: (1) the number of cancers diagnosed and standardized incidence ratio (SIR) for pancreatobiliary and other cancers during the observational period and (2) prognosis after diagnosis of AIP and IgG4-SC using standardized mortality ratio (SMR).

RESULTS

This study included 201 patients with AIP and IgG4-SC. The mean follow-up period was 5.7 years. Seven cases of pancreatic cancer were diagnosed, and the SIR was 8.11 (95% confidence interval [CI]: 7.29-9.13). Three cases of bile duct cancer were diagnosed, and the SIR was 6.89 (95% CI: 6.20-7.75). The SMR after the diagnosis of AIP and IgG4-SC in cases that developed pancreatobiliary cancer were 4.03 (95% CI: 2.83-6.99).

CONCLUSIONS

Patients with autoimmune pancreatitis and IgG4-SC were associated with a high risk of pancreatic and bile duct cancer. Patients with AIP and IgG4-SC have a worse prognosis when they develop pancreatobiliary cancer.

[Histopathologic diagnosis of solid and cystic pancreatic lesions with a focus on ductal adenocarcinoma : A vademecum for daily practice]

Pancreas pathology is constantly evolving and can present various challenges for pathologists. This paper is focused on providing helpful hints for daily routine diagnostics. During histopathological analysis of pancreas biopsies, pancreatic ductal adenocarcinoma must be distinguished not only from other solid neoplasms, but especially from its mimicker, autoimmune pancreatitis. This can be achieved by a systematic workup following clear diagnostic criteria. When analyzing samples from cystic pancreatic lesions, mucin-producing neoplasms must be detected due to their role as pancreatic cancer precursors; molecular analyses can help considerably with their detection and distinction. During frozen section examination, evaluation of the pancreatic neck margin and analysis of unclear lesions of the liver are two important tasks, which are explained further in this article. A special challenge is the evaluation of neoadjuvant treated pancreatic cancer, which requires a detailed macroscopic and microscopic workup. Finally, current advances in precision oncology and emerging approaches for pancreatic cancer within this field are discussed. With the advancement of technical possibilities and their increasingly broad implementation, the classification systems in pancreatic pathology will continue to gain in complexity, but also in accuracy.

Küttner's Tumor and Autoimmune Pancreatitis as Metachronous Manifestations of IgG4-Related Disease

Immunoglobulin G4-related disease (IgG4-RD) is a multiorgan, fibro-inflammatory condition that presents with painless organ swelling, lymphoplasmacytic infiltration, and obliterative phlebitis, often showing a favorable response to corticosteroid therapy. The most affected organs include the pancreas, kidneys, retroperitoneum, lacrimal glands, and salivary glands. Diagnosis relies on serological, imaging, and histopathological findings, with glucocorticoids as the primary treatment. Despite its reversible nature and good prognosis in many cases, long-term complications such as organ dysfunction or malignancy can still occur. International collaborative efforts have enhanced the understanding, diagnosis, and management of IgG4-RD, emphasizing the importance of comprehensive diagnostic criteria and appropriate therapeutic strategies. Herein, we present an interesting case of a geriatric male who was referred to our clinic because of concern for pancreatic cancer. We diagnosed the patient with autoimmune pancreatitis, a manifestation of IgG4-RD. The patient experienced a dramatic response to steroid therapy and is currently on maintenance therapy.

Autoimmune pancreatitis: A bibliometric analysis from 2002 to 2022

Background/Objectives

Autoimmune pancreatitis (AIP) is a distinct form of pancreatic inflammatory disease that responds well to glucocorticoid therapy. Knowledge on AIP has rapidly evolved over the past two decades. Based on bibliometric analysis, this study aimed to assess the research status of AIP over the past two decades and determine the research focus and emerging topics.

Methods

AIP-related publications published between January 1, 2002, and June 6, 2022, were retrieved from the Web of Science Core Collection. Bibliometric data were analyzed using HisCite, VOSviewer, CiteSpace, and bibliometrix package. Annual output, leading countries/regions, active institutions and authors, core journals and references, and keywords of AIP were evaluated.

Results

Overall, 1,772 publications were retrieved from 501 journals by 6,767 authors from 63 countries/regions. Japan published articles on AIP the most (n=728, 41.1%), followed by the United States (n=336, 19%), Germany (n=147, 8.3%), China (n=127, 7%), and Italy (n=107, 6%). The top three most prolific authors were Terumi Kamisawa from Tokyo Metropolitan Komagome Hospital (n=117), Kazuichi Okazaki from Kansai Medical University (n=103), and Shigeyuki Kawa from Matsumoto Dental University (n=94). Pancreas was the most productive journal regarding AIP research (n=95), followed by the Journal of Gastroenterology (n=67), Internal Medicine (n=66), Pancreatology (n=63), and World Journal of Gastroenterology (n=62). "Diagnosis" was the most mentioned keyword. "Risk," "malignancy," "outcome," "22-gauge needle," and "fine-needle aspiration" were recognized as emerging topics.

Conclusion

Japan was the leading country in AIP research. Research papers were mainly published in specialized journals. Diagnosis was the research focus. Long-term outcomes and pancreatic tissue acquisition were recognized as research frontiers for AIP.

The M-ANNHEIM-AiP-Activity-Score is useful for predicting relapse in patients with type 1 autoimmune pancreatitis

BACKGROUND/OBJECTIVES

Proper assessment of disease activity and prediction of relapse are crucial for the management of autoimmune pancreatitis (AIP). The M-ANNHEIM-AiP-Activity-Score (MAAS) has been proposed to determine disease activity and predict relapse in German and Swedish patients with AIP. MAAS is calculated using six categories: pain report, pain control, exocrine insufficiency, endocrine insufficiency, imaging, and complications. This study aimed to clarify the usefulness of MAAS to predict relapse in Japanese patients with type 1 AIP.

METHODS

We retrospectively analyzed 117 patients with type 1 AIP undergoing initial and maintenance steroid treatments at our institute between April 2006 and March 2021. AIP was diagnosed according to the Japanese Diagnostic Criteria for AIP 2018. We examined the association of MAAS with relapse during and after maintenance treatment.

RESULTS

MAAS (median, 8 points) at the start of the initial treatment was reduced after treatment (median, 4 points; P < 0.001). A MAAS ≥11 points at the start of the initial treatment was associated with relapse. The initial treatment-induced reduction of MAAS<60% was more frequent in patients with relapse (75.0%) than in patients without relapse (37.6%; P = 0.007). MAAS at the start of maintenance treatment was higher for patients with relapse (median, 5 points) than that for patients without relapse (median, 4 points; P = 0.007). MAAS ≥4 points at the start of maintenance treatment was associated with subsequent relapse.

CONCLUSIONS

MAAS is useful for predicting relapse in patients with type 1 AIP undergoing maintenance therapy.