Maintenance steroid therapy is associated with decreased risk of malignancy and better prognosis of patients with autoimmune pancreatitis: A multicenter cohort study in Japan

What Is the Latest in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is a steroid-responsive fibroinflammatory disorder with 2 clinically distinct subtypes known as type 1 autoimmune and type 2 autoimmune pancreatitis. Type 1 AIP is considered the pancreatic manifestation of immunoglobulin G4-related disease, a systemic disease often presenting with other organ involvement. Advances in understanding the unique clinical presentation, imaging findings, histopathology, and clinical course of this relatively uncommon disease have led to international consensus regarding diagnosis and treatment. While corticosteroids remain the mainstay of treatment, several emerging novel therapies have been explored primarily in the context or relapsing and refractory cases.

Endoscopic ultrasound-guided fine-needle biopsy needle can facilitate histological diagnosis of type 1 autoimmune pancreatitis

BACKGROUND

The choice between 22-gauge endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) and EUS-guided fine-needle aspiration (EUS-FNA) for histological diagnosis of type 1 autoimmune pancreatitis (AIP) is unclear. We retrospectively examined the detection rate of histological findings for AIP using EUS-FNA/FNB.

METHODS

Patients diagnosed with type 1 AIP using EUS-FNB (Franseen needle) or EUS-FNA (conventional needle) with 22-gauge needles at our hospital between 2012 and 2023 were included in this study. AIP was diagnosed according to International Consensus Diagnostic Criteria (ICDC). The detection rates of level 1 findings, which included storiform fibrosis and/or obliterative phlebitis, and level 2 histological findings were evaluated according to the ICDC.

RESULTS

The EUS-FNB and EUS-FNA groups included 25 and 24 patients, respectively. No significant differences in patient background were noted between the two groups. The detection rates of prominent filtration of lymphocytes and plasma cells along with fibrosis were 56.0% in the EUS-FNB group and 12.5% in the EUS-FNA group (p = .001). The detection rates of more than 10 IgG4-positive plasma cells per high-power microscopic field were 68.0% and 29.2% in the EUS-FNB and EUS-FNA groups, respectively (p = .007). The histological findings for levels 1 and 2 were significantly higher in the EUS-FNB group (56.0% vs. 12.5%; p = .001). Mild pancreatitis was observed in the EUS-FNB group; however, no other serious adverse events occurred.

CONCLUSION

The 22-gauge EUS-FNB yielded a higher rate of histological findings than 22-gauge EUS-FNA, suggesting that 22-gauge EUS-FNB is suitable and safe for the histological diagnosis of type 1 AIP.

Serum IgG4-negative and IgG4-positive type 1 autoimmune pancreatitis present with different clinicopathological features: An analysis of a nationwide survey in Japan

BACKGROUND/OBJECTIVE

Elevated serum IgG4 (sIgG4) is a useful diagnostic marker of type 1 autoimmune pancreatitis (AIP). This study aimed to clarify the clinicopathological characteristics of the type 1 AIP patients without elevated sIgG4 levels.

METHODS

We analyzed the clinical data of patients registered in a nationwide epidemiological survey in Japan. AIP was diagnosed according to the International Consensus Diagnostic Criteria. Patients with sIgG4 levels ≥135 mg/dl at the diagnosis were classified as sIgG4-positive AIP, and those with sIgG4 levels <135 mg/dl were as sIgG4-negative AIP.

RESULTS

A total of 1285 patients with AIP were enrolled in this study; 1128 (87.8 %) had sIgG4-positive AIP and 157 (12.2 %) had sIgG4-negative AIP. Compared to patients with sIgG4-positive AIP, those with sIgG4-negative AIP more frequently experienced inflammatory bowel diseases (3.8 % vs. 0.4 %), and less frequently developed extrapancreatic lesions (53.5 % vs. 72.3 %), including sclerosing cholangitis (30.6 % vs. 40.7 %) and sialadenitis/dacryoadenitis (5.1 % vs. 24.7 %). Histopathological examinations were performed more frequently in patients with sIgG4-negative AIP. The criterion of abundant IgG4-positive plasma cells was less frequently fulfilled by patients with sIgG4-negative AIP (28.0 % vs. 43.1 %). A Kaplan-Meier analysis showed that relapse occurred less frequently in patients with sIgG4-negative AIP (P = 0.006). Results were similar even if the patients with AIP-not otherwise specified (n = 45) were excluded.

CONCLUSIONS

Patients with sIgG4-negative type 1 AIP and those with sIgG4-positive type 1 AIP present with different clinicopathological features which suggests heterogeneity of patients with type 1 AIP. Low serum IgG4 levels could indicate low disease activity in type 1 AIP.

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.

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.

Pancreatic Ductal Adenocarcinoma with Autoimmune Pancreatitis: A Case Report and Literature Review

A 50-year-old man was diagnosed with type 1 autoimmune pancreatitis (AIP) following endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and a histopathological examination. After six months of untreated follow-up, the serum IgG4 level decreased, and the diffuse pancreatic enlargement improved; however, a pancreatic head mass became apparent. EUS-FNA of this mass revealed pancreatic ductal adenocarcinoma (PDAC) with IgG4-positive plasma cells. In addition, the resected specimen revealed PDAC, without any features of AIP. After pancreatoduodenectomy, AIP did not recur. The development of AIP in this case could be related to paraneoplastic syndrome.

Association of autoimmune pancreatitis and intraductal papillary mucinous neoplasm. A retrospective analysis from a tertiary care referral center

BACKGROUND

Autoimmune Pancreatitis (AIP) is a rare chronic inflammatory disease affecting the pancreas. Chronic pancreatic inflammation represents a risk factor for pre-neoplastic conditions such as Intraductal Papillary Mucinous Neoplasia (IPMN). Due to the rarity of AIP, the incidence, and clinical features of IPMN occurring in AIP patients remains unknown.

AIMS

In the present study we aimed to explore the relationship between AIP and IPMN and to characterize the clinical features and outcomes of IPMN occurring in the context of AIP.

METHODS

We retrospectively (2008-2020) analyzed the clinical and radiological records of a large single center cohort of patients with AIP and investigated the prevalence of IPMN. We then compared the clinical, laboratory and radiological characteristics of patients with IPMN and AIP with a cohort of patients with isolated IPMN.

RESULTS

Five hundred and nineteen patients were included in this retrospective study. Sixteen patients had concomitant IPMN and AIP(3%); 61 patients had isolated AIP (12%); 442 patients had isolated IPMN (85%). The prevalence of IPMN in patients with AIP was higher than that observed in the general population (21%vs8-10%). Worrisome Features and High-Risk Stigmata were more frequently observed in IPMN occurring together with AIP compared to isolated IPMN(p < 0.05). Based on radiological features IPMN in the context of AIP was more frequently of main-duct type compared to isolated IPMN(p < 0.05).

CONCLUSION

Our data suggest that AIP represents a chronic inflammatory condition that might favor IPMN development with high-risk features. Prolonged surveillance of these patients and longitudinal studies are required to further test the association with AIP and malignant and pre-malignant conditions.

A case report of IgG4-related hepatic inflammatory pseudotumor in a 3-year old boy

Background

Hepatic Inflammatory Pseudotumor (IPT) is an infrequent condition often masquerading as a malignant tumor, resulting in misdiagnosis and unnecessary surgical resection. The emerging concept of IgG4-related diseases (IgG4-RD) has gained widespread recognition, encompassing entities like IgG4-related hepatic IPT. Clinically and radiologically, corticosteroids and immunosuppressive therapies have proven effective in managing this condition.

Case Presentation

A 3-year-old Chinese boy presented to the clinic with an 11-month history of anemia, fever of unknown origin, and a tender hepatic mass. Blood examinations revealed chronic anemia (Hb: 6.4 g/L, MCV: 68.6 fl, MCH: 19.5 pg, reticulocytes: 1.7%) accompanied by an inflammatory reaction and an elevated serum IgG4 level (1542.2 mg/L). Abdominal contrast-enhanced computed tomography unveiled a 7.6 cm low-density mass in the right lateral lobe, while magnetic resonance imaging demonstrated slight hypointensity on T1-weighted images and slight hyperintensity on T2-weighted images, prompting suspicion of hepatic malignancy. A subsequent liver biopsy revealed a mass characterized by fibrous stroma and dense lymphoplasmacytic infiltration. Immunohistochemical analysis confirmed the presence of IgG4-positive plasma cells, leading to the diagnosis of IgG4-related hepatic IPT. Swift resolution occurred upon initiation of corticosteroid and mycophenolate mofetil therapies.

Conclusion

This study underscores the diagnostic approach to hepatic IPT, utilizing histopathology, immunostaining, imaging, serology, organ involvement, and therapeutic response. Early histological examination plays a pivotal role in clinical guidance, averting misdiagnosis as a liver tumor and unnecessary surgical interventions.