Involvement of the biliary system in autoimmune pancreatitis: a follow-up study

Japanese clinical guidelines for autoimmune pancreatitis

OBJECTIVES

As the patients with autoimmune pancreatitis (AIP) are increasing in Japan, the practical guideline for managing AIP is required to be established.

METHODS

Three committees (the professional committee for making clinical questions [CQs] and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators) were organized. Fifteen specialists for AIP extracted the specific clinical statements from a total of 871 literatures by PubMed search (approximately 1963-2008) and from a secondary database and made the CQs and statements. The expert panelists individually rated these clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid.

RESULTS

The professional committee made 13, 6, 6, and 11 CQs and statements for the concept and diagnosis, extrapancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded them as valid after a 2-round modified Delphi approach.

CONCLUSIONS

After evaluation by the moderators, the Japanese clinical guideline for AIP has been established. Further studies for the international guideline are needed after international consensus for diagnosis and treatment.

Presentation and management of post-treatment relapse in autoimmune pancreatitis/immunoglobulin G4-associated cholangitis

BACKGROUND & AIMS

Autoimmune pancreatitis (AIP) is a multisystem disorder that often has extrapancreatic manifestations such as immunoglobulin G4-associated cholangitis (IAC). Patients respond rapidly to steroids but can relapse after therapy. We assessed the clinical management of relapse in a group of patients with AIP/IAC.

METHODS

We performed a prospective study of patients diagnosed with AIP from 2004-2007 who received steroids. Treatment outcome was defined clinically, radiologically, and biochemically as response to steroids, remission after steroids, failure to wean steroids, and relapse. Steroids +/- azathioprine (AZA) were used to treat patients who failed, relapsed, or could not be weaned from steroids.

RESULTS

Twenty-eight patients with AIP were studied; 23 (82%) had IAC. All patients responded within 6 weeks to prednisolone therapy. Twenty-three patients achieved remission after a median of 5 months of treatment (range, 1.5-17 months), whereas 5 patients (18%) could not be weaned because of a disease flare. Of the patients who achieved remission, 8 of 23 (35%) subsequently relapsed. Overall, 13 of 23 patients (57%) with AIP/IAC relapsed, compared with 0 of the 5 with isolated AIP (P = .04, Fisher exact test). Steroids were increased/restarted in all patients who relapsed; 10 also received AZA. Remission was achieved and maintained in 7 patients; they remain on AZA monotherapy at a median of 14 months (range, 1-27 months).

CONCLUSIONS

Relapse or failure to wean steroids occurred in 46% of patients with AIP. Patients with IAC are at particularly high risk of relapse. AZA appears to be effective in patients with post-treatment relapse or who cannot be weaned from steroids. To view this article's video abstract, go to the AGA's YouTube Channel.

IgG4-associated cholangitis: a comparative histological and immunophenotypic study with primary sclerosing cholangitis on liver biopsy material

IgG4-associated cholangitis is a steroid-responsive hepatobiliary inflammatory condition associated with autoimmune pancreatitis that clinically and radiologically mimics primary sclerosing cholangitis. In this study, we conducted a morphological and immunohistochemical analysis of liver material obtained from individuals with IgG4-associated cholangitis, and compared these with well-characterized cases of primary sclerosing cholangitis. The study group consisted of 10 patients (9 biopsy and 1 hepatectomy case) with IgG4-associated cholangitis and 17 patients with primary sclerosing cholangitis (16 needle biopsy and 1 hepatectomy case). All patients with IgG4-associated cholangitis had pancreatic involvement as well, and six pancreatectomy samples revealed characteristic histopathological features of autoimmune pancreatitis. Primary sclerosing cholangitis cases were defined by the presence of a characteristic ERCP appearance. Clinical, pathological, radiological, and follow-up data were recorded for all cases. Portal and periportal inflammation was graded according to Ishak's guidelines. Immunohistochemical stains for IgG and IgG4 were performed. The cohort of patients with IgG4-associated cholangitis (mean age: 63 years) was older than individuals with primary sclerosing cholangitis (mean age: 44 years). Seven of these cases showed intrahepatic biliary strictures. IgG4-associated cholangitis liver samples showed higher portal (P=0.06) and lobular (P=0.009) inflammatory scores. Microscopic portal-based fibro-inflammatory nodules that were composed of fibroblasts, plasma cells, lymphocytes, and eosinophils were exclusively observed in five of the IgG4-associated cholangitis cases (50%). More than 10 IgG4-positive plasma cells per HPF (high power field) were observed in 6 of the IgG4-associated cholangitis cases (mean: 60, range: 0-140 per HPF), whereas all primary sclerosing cholangitis cases showed significantly lesser numbers (mean: 0.08, range: 0-1 per HPF). On a liver biopsy, the histological features of IgG4-associated cholangitis may be distinctive, and in conjunction with IgG4 immunohistochemical stain, may help distinguish this disease from primary sclerosing cholangitis.

Diagnostic utility of biopsy specimens for autoimmune pancreatitis

BACKGROUND AND AIMS

Infiltration of IgG4-positive plasma cells in the pancreas and other organs is characteristic of autoimmune pancreatitis (AIP). However, it is undetermined whether needle or forceps biopsy of pancreas or other organs is indeed useful for the diagnosis of AIP. We aimed to clarify this point.

METHODS

Among 39 AIP patients, tissue sampling without laparotomy was performed in 27. Biopsy of pancreas, gastric mucosa, liver, bile duct, and duodenal papilla was performed in 15, 17, 11, 5 and 7, respectively. The obtained specimens were examined for IgG4-positive plasma cells. We also examined gastric mucosa of 18 patients with pancreatic cancer as controls. When the number of IgG4-positive plasma cells was more than 10 per high-power field, we regarded it as diagnostic.

RESULTS

Diagnostic sensitivity in pancreas, gastric mucosa, liver, bile duct, and duodenal papilla was 47% (7/15), 47% (8/17), 36% (4/11), 0% (0/5), and 57% (4/7), respectively.

CONCLUSIONS

Sensitivity of IgG4 immunostaining was unsatisfactory when tissue sampling was performed by needle or forceps biopsy. Biopsy of gastric mucosa might be a good subsidiary diagnostic tool.

Autoimmune pancreatitis in Japan: overview and perspective

Since the rediscovery and definition of autoimmune pancreatitis (AIP) by Yoshida et al. in 1995, the disease has been attracting attention because of its unique clinical features and practical issues. This disease shows very impressive imaging findings, serological changes, and characteristic histopathology. It occurs most commonly in elderly males with painless jaundice or mild abdominal pain; resemblance in imaging findings between AIP and pancreatobiliary cancers poses an important practical issue of differentiation. With increasing recognition of AIP and accumulation of cases, another important feature of this disease has been revealed, i.e., association of extrapancreatic organ involvements. Initially misunderstood because it can be accompanied by other autoimmune disorders, such as Sjögren's syndrome or primary sclerosing cholangitis (PSC), AIP is now known to be associated with unique types of sialadenitis and cholangitis distinct from Sjögren's syndrome or PSC. Now the concept of "IgG4-related sclerosing disease" has become widely accepted and the list of organs involved continues to increase. With worldwide recognition, an emerging issue is the clinical definition of other possible types of autoimmune-related pancreatitis called "idiopathic duct-centric chronic pancreatitis (IDCP)" and "AIP with granulocyte epithelial lesion (GEL)" and their relation to AIP with lymphoplasmacytic sclerosing pancreatitis (LPSP). The time has arrived to establish clinical diagnostic criteria of AIP based on international consensus and to discuss regional and racial differences in the clinicopathological features of AIP. Consensus guidelines are also required for the ideal use of steroids in the treatment of AIP to suppress recurrence efficiently with minimal side effects. There are many issues to be settled in AIP; international collaboration of experts in the pancreas field is necessary to clarify the entire picture of this unique and important disease.

Autoimmune pancreatitis/IgG4-associated cholangitis and primary sclerosing cholangitis--overlapping or separate diseases?

Autoimmune pancreatitis is a recently described fibroinflammatory disease which is characterised by raised serum levels of IgG4 (in >70% of cases), and an IgG4-positive lymphoplasmacytic tissue infiltrate. A favourable and rapid clinical response to oral steroid therapy is often seen. Biliary involvement is common, and the term IgG4-associated cholangitis has recently been coined. The cholangiographic appearances of IgG4-associated cholangitis and primary sclerosing cholangitis can be difficult to differentiate. Moreover, raised levels of serum IgG4 have been recently found in 9% of patients with primary sclerosing cholangitis (a much higher frequency than for other gastrointestinal diseases), and those with raised levels appear to progress more rapidly to liver failure. Here we review the similarities and differences between the biliary disease in autoimmune pancreatitis and primary sclerosing cholangitis, and address the issue of disease overlap. Improvements in understanding the relationship between these conditions might lead to an enhanced understanding of the aetiopathogenesis, and improved treatment of both conditions.

Characteristic findings in images of extra-pancreatic lesions associated with autoimmune pancreatitis

PURPOSE

Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by a variety of extra-pancreatic involvements which are frequently misdiagnosed as lesions of corresponding organs. The purpose of this study was to clarify the diagnostic imaging features of extra-pancreatic lesions associated with autoimmune pancreatitis.

MATERIALS AND METHODS

We retrospectively analyzed diagnostic images of 90 patients with autoimmune pancreatitis who underwent computer-assisted tomography, magnetic resonance imaging, and/or gallium-67 scintigraphy before steroid therapy was initiated.

RESULTS

AIP was frequently (92.2%) accompanied by a variety of extra-pancreatic lesions, including swelling of lachrymal and salivary gland lesions (47.5%), lung hilar lymphadenopathy (78.3%), a variety of lung lesions (51.2%), wall thickening of bile ducts (77.8%), peri-pancreatic or para-aortic lymphadenopathy (56.0%), retroperitoneal fibrosis (19.8%), a variety of renal lesions (14.4%), and mass lesions of the ligamentum teres (2.2%). Characteristic findings in CT and MRI included lymphadenopathies of the hilar, peri-pancreatic, and para-aortic regions; wall thickening of the bile duct; and soft tissue masses in the kidney, ureters, aorta, paravertebral region, ligamentum teres, and orbit.

CONCLUSIONS

Recognition of the diagnostic features in the images of various involved organs will assist in the diagnosis of autoimmune pancreatitis and in differential diagnoses between autoimmune pancreatitis-associated extra-pancreatic lesions and lesions due to other pathologies.

[A case of autoimmune pancreatitis combined with extensive involvement of biliary tract]

Autoimmune pancreatitis is a distinct disease characterized by the presence of autoantibodies and hypergammaglobulinemia, inflammation of the pancreatic parenchyma, and irregular stricture of the pancreatic duct. The involvement of distal common bile duct is frequently observed, but intrahepatic bile duct involvement is very rare, which seem to have similar feature to primary sclerosing cholangitis. We report a case of the patient with autoimmune pancreatitis combined with extensive involvement of extrahepatic and intrahepatic bile duct, which had a favorable response to steroid therapy.

The role of Movat pentachrome stain and immunoglobulin G4 immunostaining in the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis is highly responsive to steroid therapy, but because it mimics pancreatic cancer, it often precipitates unnecessary surgery. Adequate diagnostic tests are needed to permit appropriate medical therapy. Lymphocytic and obliterative phlebitis are reported in the majority of cases, as are elevated IgG4-positive plasma cells, indicating their high sensitivity. Their specificities, especially when used in conjunction, however, remain largely unknown. Movat pentachrome vascular and IgG4 immunohistochemical stains were performed on a total of 15 autoimmune pancreatitis cases (11 pancreatic resections and 4 biopsies), 39 usual-type alcoholic or idiopathic chronic pancreatitis cases, 35 pancreatic ductal adenocarcinoma-associated chronic pancreatitis cases, and 29 normal pancreata. Marked and diffuse lymphocytic and obliterative venulitis were detected in all 15 cases of autoimmune pancreatitis on Movat staining (100% sensitivity). Only a single carcinoma-associated chronic pancreatitis case among all of the controls showed diffuse benign venulitis that was nonobliterative (99% specificity). Nine of 13, 9 autoimmune pancreatitis cases showed marked IgG4 immunopositivity at >or=10 positive plasma cells per x 400 field (69% sensitivity). No increased IgG4 plasma cells were found in any of 103 controls (100% specificity). In combination, all of the autoimmune pancreatitis cases had at least one (13/13) and most had both markers (9/13), whereas none of the controls had both markers. Overall, these combined stains show very promising diagnostic utility and should be considered in combination with clinical and serologic analyses in the evaluation of chronic pancreatitis suspicious for malignancy. Future validating studies on preoperative biopsies with outcome data following steroid therapy will be essential.

Autoimmune pancreatitis and IgG4-associated sclerosing cholangitis

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis characterised by a high serum IgG4 concentration and complications that include various extrapancreatic manifestations, one of which is sclerosing cholangitis. In AIP patients, infiltration of abundant IgG4-positive plasma cells and dense fibrosis are commonly observed in the pancreas and wall of the bile duct and gallbladder. The major symptom at onset of AIP is obstructive jaundice caused by stricture of the bile duct, and this requires differential diagnosis of AIP from pancreato-biliary malignancies and primary sclerosing cholangitis (PSC). Recently, there have been reports of particular cases of sclerosing cholangitis with a high serum IgG4 level and cholangiographic and pathological findings comparable to those observed in AIP patients. Being apparently different from PSC and similar to that in AIP, sclerosing cholangitis with and without AIP shows a clinical response to steroid therapy and thus is designated as 'IgG4-associated sclerosing cholangitis'. The pathogenesis of AIP and IgG4-associated sclerosing cholangitis remains at yet undetermined.

Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: A systematic literature review and meta-analysis

High circulating serum immunoglobulin G4 (IgG4) levels have been proposed as a marker of autoimmune pancreatitis (AIP). The aim of the present study was to review the data existing in the English literature on the usefulness of the IgG4 serum levels in the diagnosis and follow up of patients with AIP. A total of 159 patients with AIP and 1099 controls were described in seven selected papers reporting the usefulness of serum IgG4 in diagnosing AIP. In total, 304 controls had pancreatic cancer, 96 had autoimmune diseases, and the remaining 699 had other conditions. The summary receiver-operating characteristic curve analysis was carried out by means of Meta-DiSc open-access software. Serum IgG4 showed good accuracy in distinguishing between AIP and the overall controls, pancreatic cancer and other autoimmune diseases (area under the curve [+/- SE]: 0.920 +/- 0.073, 0.914 +/- 0.191, and 0.949 +/- 0.024, respectively). The studies analyzed showed significantly heterogeneous specificity values in each of the three analyses performed. The analysis of the four studies comparing AIP and pancreatic cancers also showed significantly heterogeneous values of sensitivities and odds ratios. Regarding the usefulness of IgG4 as a marker of efficacy of steroid treatment, a decrease in the serum concentrations of IgG4 was found in the four available studies. The serum IgG4 subclass is a good marker of AIP, and its determination should be included in the diagnostic workup of this disease. However, the heterogeneity of the studies published until now means that more studies are necessary in order to better evaluate the true accuracy of IgG4 in discriminating AIP versus other autoimmune diseases.

Review of 67 patients with autoimmune pancreatitis in Korea: a multicenter nationwide study

OBJECTIVES

The ideal diagnostic criteria of autoimmune pancreatitis (AIP) are still challenging. Therefore, we investigated the clinical features of AIP in Korea and assessed the clinical use of new Korean diagnostic criteria.

METHODS

We reviewed 67 patients with AIP enrolled in 16 hospitals via a multicenter study. The diagnosis was confirmed according to the Korean diagnostic criteria that included pancreatic imaging, laboratory findings, histopathology, and response to steroid.

RESULTS

Mean age of the patients was 56 years, and 73% were men. Obstructive jaundice (52%) was the most common symptom, and 14 patients (21%) had other organ involvement. Fifty-four patients (81%) revealed diffuse swelling of the pancreas. Either immunoglobulin (Ig)G or IgG4 was elevated in 76%. According to the Korean criteria, 65 patients had definite diagnostic criteria, and 2 patients had probable criteria. Fifteen patients were fulfilled with image, serological, and histopathologic criteria, and 4 patients could be diagnosed with image and steroid responsiveness. Ten patients experienced recurrent attacks of AIP during the mean 20-month follow-up.

CONCLUSIONS

Among 67 cases of AIP, either IgG or IgG4 was elevated in 76% of patients, and 14 patients (21%) had other organ involvement. New Korean diagnostic criteria are useful for diagnosis of AIP.

Recent advances in autoimmune pancreatitis: concept, diagnosis, and pathogenesis

Recent advances support the concept of autoimmune pancreatitis (AIP) as a unique systemic disease, because it shows occasional extrapancreatic lesions such as sclerosing cholangitis, sclerosing sialoadenitis, and retroperitoneal fibrosis, pathological features similar to those of fibrosis, and abundant infiltration of IgG4-positive plasma cells, and it is steroid responsive. Based on these findings, several diagnostic criteria have been proposed. Although AIP is accepted worldwide as a unique clinical entity, its pathogenetic mechanism remains unclear. To clarify its pathogenesis, its genetic background, humoral immunity, candidate target antigens including self-antigens and molecular mimicry by microbes, and cellular immunity including regulatory T cells, the complement system, and experimental models are reviewed. On the basis of this review, we hypothesize that the pathogenesis of AIP involves a biphasic mechanism consisting of "induction" and "progression." In the early stage, the initial response to self-antigens [lactoferrin, carbonic anhydrase (CA)-II, CA-IV, pancreatic secretory trypsin inhibitor, and alpha-fodrin] and molecular mimicry (Helicobacter pylori) are induced by decreased naïve regulatory T cells (Tregs), and T-helper (Th) 1 cells release proinflammatory cytokines [interferon-gamma, interleukin (IL)-1beta, IL-2, and tumor necrosis factor alpha]. In the chronic stage, progression is supported by increased memory Tregs and Th2 immune responses. The classical complement system pathway may be activated by the IgG1 immune complex. As Tregs seem to play an important role in progression as well as in induction of the disease, further studies are necessary to clarify the pathogenesis of AIP.

Clinical features of primary sclerosing cholangitis with onset age above 50 years

BACKGROUND

Although there are two peaks in the age distribution of primary sclerosing cholangitis (PSC) in Japan, the clinical differences between the patients with an older or younger onset age have not been reported.

METHODS

We compared clinical features of 18 patients with onset age less than 50 years (younger group) and ten PSC patients with onset age above 50 years (older group).

RESULTS

An association with ulcerative colitis (UC) was recognized in six patients in the younger group and in one in the older group. High serum IgE (>170 IU/ml) was observed more frequently in the older than in the younger group (1/10 vs. 7/8, P = 0.0029). Mean serum IgM tended to be higher in the younger group (198 vs. 119 mg/dl, P = 0.083). More patients received liver transplantation or continuous bile drainage, or developed liver failure or cholangiocellular carcinoma in the younger than in the older group (11/18 vs. 1/10, P = 0.016).

CONCLUSIONS

Older PSC patients have higher IgE, possibly less association with UC, lower IgM, and a better prognosis. The pathogenesis of PSC may be different between older and younger patients.

Abdominal extrapancreatic lesions associated with autoimmune pancreatitis: Radiological findings and changes after therapy

PURPOSE

To evaluate imaging findings of abdominal extrapancreatic lesions associated with autoimmune pancreatitis (AIP) and changes after steroid therapy.

METHODS AND MATERIALS

This study included nine AIP patients with abdominal extrapancreatic lesions, which were determined by retrospective radiological review. CT (initial and follow-up, n=9) and MR imaging (initial, n=5) were reviewed by two radiologists in consensus to determine imaging characteristics (i.e., size, number, attenuation or signal intensity, and contrast enhancement of the lesions, and the presence of overlying capsule retraction) and evaluate changes with steroid therapy of abdominal extrapancreatic lesions associated with AIP.

RESULTS

The most common abdominal extrapancreatic lesion associated with AIP was retroperitoneal fibrosis (RPF) in six patients. In five patients, CT and MR imaging revealed single or multiple, round- or wedge-shaped, hypoattenuating or hypointense, enhancing lesions in the renal cortex or pelvis. Other lesions included a geographic, ill-defined, hypoattenuating lesion with or without overlying capsule retraction in the liver in two and bile duct dilatation with or without bile duct wall thickening in four. Over a follow-up period of 6-81 months, CT exams of eight patients demonstrated partial or complete improvement of the abdominal extrapancreatic lesions, albeit their improvement in general lagged behind that of the pancreatic lesion.

CONCLUSION

On CT or MR imaging, the abdominal extrapancreatic lesions associated with AIP are various in the retroperitoneum, liver, kidneys and bile ducts, and are reversible with steroid therapy.

Autoimmune cholangitis mimicking periductal-infiltrating cholangiocarcinoma

We report here on the imaging findings of a case of autoimmune cholangitis that involved a segmental bile duct of the liver. Abdominal computed tomogram showed ill-defined low-attenuation lesion at the hilar portion of the right hepatic lobe, and this was associated with peripheral intrahepatic bile duct dilatation. Gadolinium enhanced liver magnetic resonance imaging (MRI) showed wall thickening with periductal enhancement along the segmental tributaries of the right intrahepatic bile duct. The pathologic findings revealed lymphoplasmacytic infiltration and severe fibrosis, indicating autoimmune cholangitis.

Autoimmune pancreatitis

Autoimmune pancreatitis is the pancreatic manifestation of a systemic disorder that affects various organs, including the bile duct, retroperitoneum, kidney, and parotid and lacrimal glands. It represents a recently described subset of chronic pancreatitis that is immune mediated and has unique histologic, morphologic, and clinical characteristics. A hallmark of the disease is its rapid response to corticosteroid treatment. Although still a rare disease, autoimmune pancreatitis is increasingly becoming recognized clinically, leading to evolution in the understanding of its prognosis, clinical characteristics, and treatment.

Immunoglobulin G4-associated cholangitis

PURPOSE OF REVIEW

Immunoglobulin G4-associated cholangitis is a recently identified clinical entity characterized by infiltration of immunoglobulin G4 -bearing plasma cells in bile ducts and other affected tissues. This review is focused mainly on the most recent studies published during the last 2 years that have increased our understanding of this clinical entity.

RECENT FINDINGS

Investigations concerning the immune mechanisms, liver histology in immunoglobulin G4-associated cholangitis and reports of clinical and radiological features of the condition as well as medical therapy are discussed.

SUMMARY

Immunoglobulin G4-associated cholangitis was found to be characterized by overproduction of T helper 2 cells, and regulatory cytokines (interleukin-10 and transforming growth factor-beta) were upregulated in the affected tissues. Immunoglobulin G4 immunostaining in a range of clinically involved tissues in patients with immunoglobulin G4-associated cholangitis and autoimmune pancreatitis was found to be important for diagnostic purposes, which is probably most useful in cases with normal immunoglobulin G4 levels. It has become apparent that multiple measurements of immunoglobulin G4 levels in patients with clinically suspected immunoglobulin G4-associated cholangitis are important, revealing abnormally high levels in patients with normal immunoglobulin G4 on initial testing. Most patients respond to steroids initially but disease relapse seems to be common. A significant proportion of primary sclerosing cholangitis patients have elevated immunoglobulin G4 levels.

Update on the diagnosis and treatment of autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is the pancreatic manifestation of a systemic fibroinflammatory disease (IgG4-related systemic disease) in which affected organs demonstrate dense lymphoplasmacytic infiltration with abundant IgG4-positive cells. The diagnosis of AIP and its differentiation from pancreatic cancer, its main differential diagnosis, remains a clinical challenge. The five cardinal features of AIP are characteristic histology, imaging, and serology; other organ involvement; and response to steroid therapy. Recent advances in our understanding of these features have resulted in enhanced recognition and diagnosis of this benign disease. This in turn has resulted in the avoidance of unnecessary surgical procedures for suspected malignancy. This article reviews recent updates in the diagnosis and treatment of autoimmune pancreatitis.

Inflammatory abdominal aortic aneurysm: close relationship to IgG4-related periaortitis

Inflammatory abdominal aortic aneurysm (AAA) is a member of a family of disorders referred to as "chronic periaortitis" together with retroperitoneal fibrosis. Retroperitoneal fibrosis is included in IgG4-related disease, which is characterized by numerous infiltrating IgG4-positive plasma cells and high serum IgG4 concentrations. However, the relationship between IgG4-related disease and inflammatory AAA has not been documented. In this study, we examined the clinicopathologic characteristics of inflammatory (10 cases) and atherosclerotic (22 cases) AAAs, based on the hypothesis that inflammatory AAA might be related to IgG4-related disease. Cases of inflammatory AAA could be classified into 2 groups based on immunostaining of IgG4. Four patients showed diffuse infiltration of abundant IgG4-positive plasma cells (IgG4-related cases), whereas the remaining 6 cases of inflammatory AAA and all cases of atherosclerotic AAA had only a few IgG4-positive plasma cells (non-IgG4-related cases). IgG4-related inflammatory AAA was pathologically characterized by the frequent infiltration of eosinophils, lymph follicle formation, perineural inflammatory extension, and inconspicuous infiltration of neutrophils compared with non-IgG4-related inflammatory AAA. Obliterative phlebitis, which is venous occlusion with inflammatory cell infiltration, is observed in all IgG4-related cases. In addition, serum IgG4 concentrations were significantly higher in IgG4-related inflammatory AAA (109 to 559 mg/dL, normal range: 4 to 110 mg/dL) than non-IgG4-related inflammatory AAA (32 to 59 mg/dL) and all atherosclerotic AAA (12 to 83 mg/dL). In conclusion, inflammatory AAAs might be classified into 2 groups: IgG4-related or nonrelated. The former might be one of the IgG4-related diseases, and could be included in IgG4-related periaortitis together with retroperitoneal fibrosis.

Immunoglobulin G4-associated cholangitis: clinical profile and response to therapy

BACKGROUND & AIMS

Immunoglobulin (Ig)G4-associated cholangitis (IAC) is the biliary manifestation of a steroid-responsive multisystem fibroinflammatory disorder in which affected organs have a characteristic lymphoplasmacytic infiltrate rich in IgG4-positive cells. We describe clinical features, treatment response, and predictors of relapse in IAC and compare relapse rates in IAC with intrapancreatic vs proximal bile duct strictures.

METHODS

We reviewed clinical, serologic, and imaging characteristics and treatment response in 53 IAC patients.

RESULTS

IAC patients generally were older (mean age, 62 y) men (85%), presenting with obstructive jaundice (77%) associated with autoimmune pancreatitis (92%), increased serum IgG4 levels (74%), and abundant IgG4-positive cells in bile duct biopsy specimens (88%). At presentation, biliary strictures were confined to the intrapancreatic bile duct in 51%; the proximal extrahepatic/intrahepatic ducts were involved in 49%. Initial presentation was treated with steroids (n = 30; median follow-up period, 29.5 months), surgical resection (n = 18; median follow-up period, 58 months), or was conservative (n = 5; median follow-up period, 35 months). Relapses occurred in 53% after steroid withdrawal; 44% relapsed after surgery and were treated with steroids. The presence of proximal extrahepatic/intrahepatic strictures was predictive of relapse. Steroid therapy normalized liver enzyme levels in 61%; biliary stents could be removed in 17 of 18 patients. Fifteen patients treated with steroids for relapse after steroid withdrawal responded; 7 patients on additional immunomodulatory drugs remain in steroid-free remission (median follow-up period, 6 months).

CONCLUSIONS

IAC should be suspected in unexplained biliary strictures associated with increased serum IgG4 and unexplained pancreatic disease. Relapses are common after steroid withdrawal, especially with proximal strictures. The role of immunomodulatory drugs for relapses needs further study.

Autoimmune pancreatitis

Autoimmune pancreatitis is a form of chronic pancreatitis of presumed autoimmune aetiology. The disease is characterised with clinical, serological, histomorphological and imaging features. Autoimmune pancreatitis is recognised as a T-cell-mediated specific disease with lymphoplasmatic infiltration of pancreatic tissue and pancreatic parenchyma fibrosis. Serum immunoglobulin IgG or IgG4 and antibodies (rheumatoid factor, lactoferrin antibodies, carbonic anhydrase II, etc) are usually increased. But the lack of specific biochemical markers is a major drawback in the diagnosis of autoimmune pancreatitis. The Japan Pancreas Society proposed diagnostic criteria for autoimmune pancreatitis as the presence antibodies, pancreas enlargement and pancreatic duct narrowing, lymphoplasmatic infiltration, response to corticosteroid therapy, and association with other autoimmune diseases such as autoimmune hepatitis, sclerosing cholangitis, primary biliary cirrhosis, sialoadenitis, inflammatory bowel disease and Sjögren syndrome. New criteria (HISORt Criteria) incorporate imaging changes, organ involvement, specific elevation of IgG4 subclass and histopathological markers. Autoimmune pancreatitis could be associated with diabetes mellitus and exocrine pancreatic dysfunction. Clinically, autoimmune pancreatitis is a disease with mild symptoms; severe attacks of abdominal pain are not typical. Typically, pancreatic calcifications and pseudocyst are absent; on the other hand jaundice and/or pancreatic mass are frequent signs, and both make differential diagnosis with pancreatic cancer difficult. From a practical point of view, in an elderly male presenting with obstructive jaundice and pancreatic mass, autoimmune pancreatitis is one of the differential diagnoses to avoid unnecessary surgical therapy.

Pancréatite auto-immune

Chronic autoimmune pancreatitis is an entity distinct from all other forms of chronic pancreatitis. It is expressed by signs of acute or chronic pancreatitis, sometimes associated with cholestatic jaundice. In imaging, it may appear as diffuse (duct destructive) or pseudotumoral lesions. These 2 aspects are probably different clinical forms of chronic autoimmune pancreatitis. Some autoimmune diseases are associated with chronic autoimmune pancreatitis, but not consistently. One such disease involves a bile disorder very similar to primary sclerosing cholangitis but responsive to corticosteroid treatment. Pancreatitis may be a sign of intestinal inflammatory diseases (and vice versa): testing for Crohn's disease and ulcerative rectocolitis is justified in patients with idiopathic pancreatitis. Chronic autoimmune pancreatitis must be routinely considered in patients with a pancreatic tumor that is for a clinical, epidemiologic, serologic or imaging reason not completely consistent with pancreatic adenocarcinoma. A short corticosteroid therapy (< 4 weeks) is probably less harmful in a patient with pancreatic adenocarcinoma than pancreatectomy (or chemotherapy) in patients with chronic autoimmune pancreatitis. Diagnosis depends on a body of clinical and radiologic evidence. The diagnostic value of serologic markers and especially of autoantibodies must be clarified in the future.

Sclerosing cholangitis associated with autoimmune pancreatitis

Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by irregular narrowing of the pancreatic duct, pancreatic swelling, and a favorable response to corticosteroids, in which the autoimmune mechanism is postulated in the pathogenesis. High serum immunoglobulin (Ig)G4 concentrations and various types of extrapancreatic involvement are prominent features of this disease. Sclerosing cholangitis is a major extrapancreatic lesion of autoimmune pancreatitis that has been regarded as primary sclerosing cholangitis (PSC) complicating chronic pancreatitis. Because sclerosing cholangitis associated with autoimmune pancreatitis (SC-AIP) also favorably responds to corticosteroid therapy, it should be differentiated from PSC. Useful points regarding the differentiation between SC-AIP and PSC are as follows: (i) PSC occurs in younger and SC-AIP in older individuals; (ii) obstructive jaundice is more frequently seen in SC-AIP; (iii) PSC is complicated with inflammatory bowel disease, whereas SC-AIP is complicated with so called extrapancreatic lesions of AIP; (iv) high serum IgG4 concentrations are frequently seen in SC-AIP; (v) a cholangiogram may differentiate the two conditions to some extent; (vi) abundant IgG4-bearing plasma cell infiltration is seen in SC-AIP; and (vii) steroid therapy is effective for SC-AIP. IgG4-related sclerosing cholangitis without pancreatic lesion may be a metachronous phenotype of SC-AIP, and also should be differentiated from PSC. The pathogenesis of AIP and SC-AIP remains unclear. The complement activation system of the classical pathway may be contributing in some cases.

Tubulointerstitial nephritis associated with IgG4-related autoimmune disease

Autoimmune pancreatitis is a chronic fibroinflammatory condition primarily affecting the pancreas. Recent accumulating evidence suggested that autoimmune pancreatitis is a systemic autoimmune disease (immunoglobulin G4 [IgG4]-related autoimmune disease) affecting various organs with dense infiltration of IgG4-positive mononuclear cells. Tubulointerstitial nephritis is still a mysterious disease with an unknown cause. We report 2 cases of tubulointerstitial nephritis associated with autoimmune pancreatitis. In these patients, dense infiltrations of IgG4-positive mononuclear cells were observed in renal interstitium, with high serum IgG4 levels. Furthermore, in patient 1, who had sclerosing cholangitis, serum alkaline phosphatase and serum creatinine levels changed synchronously. Steroid therapy was followed by improved renal function and serum IgG4 levels in both patients. Because tubulointerstitial nephritis associated with IgG4-related autoimmune disease shows a favorable response to steroids and the renal dysfunction and pancreatic dysfunction are reversible, awareness of this entity is necessary for early diagnosis and prompt treatment. In addition, these cases support the hypothesis that IgG4-related autoimmune disease could be one cause of tubulointerstitial nephritis.

Immunoglobin G4-hepatopathy: association of immunoglobin G4-bearing plasma cells in liver with autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is characterized by high serum immunoglobin (Ig) G4 concentrations, lymphoplasmacytic inflammation, and a favorable response to corticosteroid treatment. Since liver dysfunction is frequently seen in AIP patients, we investigated hepatic histopathology and its clinical significance in patients with AIP. We examined the clinical features, histology, and immunoglobin G (IgG)4-bearing plasma cell infiltration of liver biopsies from 17 patients with AIP and 63 patients with either autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, or chronic viral hepatitis and histological changes in the 7 of 17 livers before and after glucocorticoid therapy. The liver histology of AIP was classified into 5 patterns: evident portal inflammation with or without interface hepatitis (6 cases), large bile-duct obstructive features (8 cases), portal sclerosis (8 cases), lobular hepatitis (5 cases), and canalicular cholestasis (4 cases); some of the histological features coexisted in the same liver. The number of IgG4-bearing plasma cells was significantly higher in AIP patients than controls (P < 0.01), and was significantly correlated with serum IgG4 concentration (P = 0.0014, r = 0.709). Glucocorticoid therapy reduced IgG4-bearing plasma cell infiltration in the liver (P = 0.031) and ameliorated other histological findings. In conclusion, virtually all AIP liver biopsies showed evidence of various pathological changes and infiltration of IgG4-bearing plasma cells. These features were ameliorated by steroid therapy, suggesting that the liver is concurrently affected in AIP, and that liver biopsies can provide significant information in the clinical evaluation and diagnosis of AIP.

Clinicopathological differentiation between sclerosing cholangitis with autoimmune pancreatitis and primary sclerosing cholangitis

BACKGROUND

The present study was undertaken to identify the clinicopathological differences between sclerosing cholangitis with autoimmune pancreatitis (SC-AIP) and primary sclerosing cholangitis (PSC).

METHODS

We retrospectively compared the clinical, cholangiographic, and liver biopsy findings between 24 cases of PSC and 24 cases of SC-AIP.

RESULTS

Patient age at the time of diagnosis was significantly lower in the PSC group than in the SC-AIP group. The peripheral blood eosinophil count was significantly higher in the PSC group than in the SC-AIP group, but the serum IgG4 level was significantly higher in the SC-AIP group. Cholangiography revealed band-like strictures, beaded appearance, and pruned-tree appearance significantly more frequently in PSC, whereas segmental strictures and strictures of the distal third of the common bile duct were significantly more common in SC-AIP. Liver biopsy revealed fibrous obliterative cholangitis only in the PSC specimens. No advanced fibrous change corresponding to Ludwig's stages 3 and 4 was observed in any of the SC-AIP specimens. IgG4-positive plasma cell infiltration of the liver was significantly more severe in SC-AIP than in PSC. Subsequent cholangiography showed no improvement in any of the PSC cases, but all SC-AIP patients responded to steroid therapy, and improvement in the strictures was observed cholangio-graphically.

CONCLUSIONS

Based on the differences between the patients' ages and blood chemistry, cholangiographic, and liver biopsy findings, SC-AIP should be differentiated from PSC.

A case of sclerosing cholangitis with autoimmune pancreatitis evaluated by FDG-PET

The extrapancreatic bile duct lesions in autoimmune pancreatitis are termed sclerosing cholangitis (SC with AIP), which is known to complicate AIP somewhat more frequently than other extrapancreatic lesions. In cases of SC with AIP, differentiation from primary SC, pancreatic cancer, and bile duct cancer is often difficult. In our patient, pancreatic cancer had to be ruled out at admission, given the findings of obstructive jaundice, pancreatic duct stenosis, and swelling of the pancreas. Fluorine-18-fluorodeoxyglucose positron emission tomography was useful in checking for the presence of extrapancreatic lesions, including SC, and was also useful in the evaluation of the response to steroid therapy for following the course of AIP.

Autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a benign, IgG4-related, fibroinflammatory form of chronic pancreatitis that can mimic pancreatic ductal adenocarcinoma both clinically and radiographically. Laboratory studies typically demonstrate elevated serum IgG4 levels and imaging studies reveal a diffusely or focally enlarged pancreas with associated diffuse or focal narrowing of the pancreatic duct. The pathologic features include periductal lymphoplasmacytic inflammation, obliterative phlebitis, and abundant IgG4-positive plasma cells. The treatment of choice for AIP is steroid therapy. Diagnostic criteria for AIP have been proposed that incorporate histologic, radiographic, serologic, and clinical information.

Th2 and regulatory immune reactions are increased in immunoglobin G4-related sclerosing pancreatitis and cholangitis

Immunoglobin G (IgG) 4-related sclerosing pancreatitis and cholangitis (autoimmune pancreato-cholangitis [AIPC]) are recently recognized disease entities characterized by high serum IgG4 concentrations and sclerosing inflammation with numerous IgG4-positive plasma cells, although the underlining immune mechanism remains only speculative. In this study, the immunopathogenesis of AIPC was examined with respect to the production of cytokines in situ and the possible involvement of regulatory T cells (Tregs) using fresh (5 cases) and formalin-fixed (28 cases) specimens of AIPC and related extra-pancreatobiliary lesions. Quantitative real-time polymerase chain reaction revealed that AIPC and extra-pancreatobiliary lesions had significantly higher ratios of interleukin (IL)-4/interferon-gamma (IFN-gamma) (45.8-fold), IL-5/IFN-gamma (18.7-fold), IL-13/interferon (IFN)-gamma (20.7-fold), IL-10/CD4 (45.3-fold), and tumor growth factor (TGF)-beta/CD4 (39.4-fold) than did primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC). Lymphocytes with signals for IL-4 and IL-10 were frequently found in AIPC by in situ hybridization. The expression of Foxp3 messenger RNA, a transcription factor specific for naturally arising CD4(+)CD25(+) Tregs, was significantly increased in AIPC and extra-pancreatobiliary lesions in comparison to PSC and PBC (36.4-fold). Immunohistochemically, CD4(+)CD25(+)Foxp3(+) cells were frequently found in AIPC, while few were found in PSC and other disease controls. Taken together, AIPC could be characterized by the over-production of T helper (Th) 2 and regulatory cytokines. Tregs might be involved in the in situ production of IL-10 and TGF-beta, which could be followed by IgG4 class switching and fibroplasia.

CONCLUSION

AIPC is a unique inflammatory disorder characterized by an immune reaction predominantly mediated by Th2 cells and Tregs.

Clinical features of autoimmune pancreatitis

Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by a high serum IgG4 concentration, and complications involving various extrapancreatic lesions. It should be emphasized that autoimmune pancreatitis is easily misdiagnosed as pancreatic cancer. This disease predominantly affects elderly men. The major symptom at onset is obstructive jaundice, while severe abdominal pain is rare. Blood tests have shown abnormal results, which could be attributed mainly to the obstructive jaundice. With regard to autoantibodies, the positive rate for the antinuclear antibody is 40%; however, disease-specific autoantibodies are rarely found. About half of the patients with autoimmune pancreatitis have shown exocrine and endocrine dysfunctions. IgG4 is a sensitive and specific marker for diagnosing autoimmune pancreatitis. In differentiating between pancreatic cancer and autoimmune pancreatitis, IgG4 shows a sensitivity of 90%, a specificity of 98%, and an accuracy of 95%. HLA DRB1*0405-DQB1*0401 alleles are significantly associated with autoimmune pancreatitis, and may present a specific peptide which triggers the autoimmune response. Various imaging findings have shown pancreatic swelling, irregular narrowing of the main pancreatic duct, and stenosis of the lower bile duct. Histology shows a significant presence of lymphocytes, plasma cell infiltration, and fibrosis with abundant IgG4-bearing plasma cell infiltration. After corticosteroid treatment, imaging findings and pancreatic functions usually improve significantly. It is probable that autoimmune pancreatitis is an essentially progressive condition resulting in pancreatic stone formation in a similar way to ordinary chronic pancreatitis.

Treatment for autoimmune pancreatitis: consensus on the treatment for patients with autoimmune pancreatitis in Japan

Autoimmune pancreatitis (AIP) has been characterized by unique clinical imaging, immunological findings, and the effectiveness of steroid therapy. A set of clinicopathological criteria for AIP was proposed by the Japan Pancreatic Society in 2002, and AIP has come to be widely recognized among general digestive clinicians. However, the indication of steroid therapy for AIP is still not well established, and furthermore the therapeutic doses and method of administration of steroid therapy is also unclear. Recently, an epidemiological survey of all the treatments used for AIP in Japan was conducted by the Research Committee of Intractable Pancreatic Diseases, and their report "Consensus for a Treatment of Autoimmune Pancreatitis" was produced. In a comparison of the results of steroid therapy and nonsteroid therapy for AIP in relation to the rate of complete remission, the recurrence rate, and the period needed to guarantee complete remission, it was thought that the administration of a steroid should be a standard therapy for AIP. However, if the diagnosis of AIP is still uncertain, steroid therapy should be given with caution. In addition, even when AIP still appears to be possible after a course of steroid therapy, a re-evaluation should be carried out taking pancreatic carcinoma into consideration. An initial steroid dose of 30-40 mg per day is recommended. With continuous and careful observations of the clinical manifestations, laboratory data, and imaging findings after administration of the initial dose of steroid for 2-4 weeks, the quantity of steroid can be reduced gradually to a maintenance dose in 2-3 months, and then reduced to 2.5-5 mg per day after remission. The recommended period of maintenance treatment is still unclear, but the administration of the steroid could be stopped after a period of about 6-12 months of treatment, although the patient should be monitored for clinical manifestations of improvement. In addition, the patient's progress should be followed taking recurrence into consideration. In order to evaluate the effectiveness of steroid therapy, follow-up observations should include biochemical examinations of blood findings such as serum gamma-globulin, IgG, and IgG 4, imaging findings, and clinical manifestations such as jaundice and abdominal discomfort.

Autoimmune pancreatitis with retroperitoneal fibrosis which responded to steroid therapy but was complicated with refractory renal dysfunction

A 58-year-old male had been diagnosed as having autoimmune pancreatitis (AIP) from the results of serological examinations and image findings. He was treated with prednisolone (PSL) for 3.5 months. Fifteen months later, follow-up CT revealed the main pancreatic duct (MPD) dilatation in the pancreas body to tail and right hydronephrosis caused by complicated retroperitoneal mass. We diagnosed him as having recurrent AIP with retroperitoneal fibrosis, and restarted PSL treatment. After one month, Examinations indicated amelioration of the MPD dilatation and right hydronephrosis, but not the right renal failure. This case indicates the importance of maintenance of PSL treatment.

Prevalence and distribution of extrapancreatic lesions complicating autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by high serum IgG4 concentrations and abundant IgG4-bearing plasma cell infiltration in the pancreatic lesion, and it has been reported to be associated with a variety of extrapancreatic lesions, leading us to postulate the concept of a systemic inflammatory disease. To confirm this, we clarified the exact distribution of these extrapancreatic lesions and provide a panoramic view of them.

METHODS

The frequency, distribution, clinical characteristics, and pathology of five extrapancreatic lesions were determined in 64 patients with autoimmune pancreatitis by examining clinical and laboratory findings.

RESULTS

The most frequent extrapancreatic lesion was hilar lymphadenopathy (80.4%), followed by extrapancreatic bile duct lesions (73.9%), lachrymal and salivary gland lesions (39.1%), hypothyroidism (22.2%), and retroperitoneal fibrosis (12.5%). No patients had all five types of lesions. Patients with hilar lymphadenopathy or lachrymal and salivary gland lesions were found to have significantly higher IgG4 levels than those without (P = 0.0042 and 0.0227, respectively). Patients with three lesions were found to have significantly higher IgG4 levels than those with no lesion, suggesting that patients with multiple extrapancreatic lesions have active disease. Similar to pancreatic lesions, extrapancreatic lesions have a characteristic histological finding of abundant IgG4-bearing plasma cell infiltration, and they respond favorably to corticosteroid therapy.

CONCLUSIONS

Autoimmune pancreatitis was recognized as a systemic inflammatory disease. Furthermore, recognition of these characteristic findings will aid in the correct diagnosis of this disease.

Pyogenic liver abscess after choledochoduodenostomy for biliary obstruction caused by autoimmune pancreatitis

A 68-year-old man underwent cholecystectomy and choledochoduodenostomy for biliary obstruction and nephrectomy for a renal tumor. Based on clinical and histopathologic findings, autoimmune pancreatitis (AIP) was diagnosed. The renal tumor was diagnosed as a renal cell cancer. Steroid therapy was started and thereafter pancreatic inflammation improved. Five years after surgery, the patient was readmitted because of pyrexia in a preshock state. A Klebsiella pneumoniae liver abscess complicated by sepsis was diagnosed. The patient recovered with percutaneous abscess drainage and administration of intravenous antibiotics. Liver abscess recurred 1 mo later but was successfully treated with antibiotics. There has been little information on long-term outcomes of patients with AIP treated with surgery. To our knowledge, this is the second case of liver abscess after surgical treatment of AIP.

[Autoimmune pancreatitis: beneficial effects of corticosteroid therapy on biliary and metabolic complications]

Auto-immune pancreatitis is rare and its evolution includes both the usual complications of chronic pancreatites, such as diabetes and specific consequences and complications including extension of inflammatory lesions of the extra or intrahepatic biliary tract. One particular characteristic of these complications is that they are sensitive to cortisone therapy, as illustrated by the case we report here.

[Autoimmune pancreatitis--a surgical disease?]

The term autoimmune pancreatitis (AIP) describes a nonalcoholic, chronic lymphoplasmocytic pancreatitis. The lymphoplasmocytic infiltration is characterized by periductal localization of predominantly CD4-positive T cells, fibrosis, and acinar atrophy, frequently resulting in stenosis of the main pancreatic and distal common bile ducts. Imaging studies often reveal a diffuse narrowing of the pancreatic main duct and swelling of the pancreatic head wrongly suggesting the presence of a malignant tumor. Clinical signs include mild abdominal pain, jaundice, recurrent episodes of acute pancreatitis, and even new-onset diabetes mellitus. Additionally, AIP can be associated with other autoimmune diseases such as Sjögren's syndrome, primary sclerosing cholangitis, chronic inflammatory bowel diseases, and retroperitoneal fibrosis. Serological markers include autoantibodies and increased levels of gamma globulin and especially IgG4. Steroids seem to be effective in improving clinical symptoms as well as in the resolution of pancreatic and bile duct narrowing. This distinguishes AIP from other forms of pancreatitis and from pancreatic neoplasms. Further studies of the underlying pathophysiologic mechanisms, prognosis, and new diagnostic tools are needed to provide adequate and effective treatment in the future. In this article, we summarize the current knowledge about AIP and present 17 cases that underwent surgical resection at our institution from 2003 to 2004.

Autoimmune pancreatitis: proposal of IgG4-related sclerosing disease

Autoimmune pancreatitis (AIP) is a peculiar type of pancreatitis of presumed autoimmune etiology. Many new clinical aspects of AIP have been clarified during the past 10 years, and AIP has become a distinct entity recognized worldwide. However, its precise pathogenesis or pathophysiology remains unclear. As AIP dramatically responds to steroid therapy, accurate diagnosis of AIP is necessary to avoid unnecessary surgery. Characteristic dense lymphoplasmacytic infiltration and fibrosis in the pancreas may prove to be the gold standard for diagnosis of AIP. However, since it is difficult to obtain sufficient pancreatic tissue, AIP should be diagnosed currently based on the characteristic radiological findings (irregular narrowing of the main pancreatic duct and enlargement of the pancreas) in combination with serological findings (elevation of serum gamma-globulin, IgG, or IgG4, along with the presence of autoantibodies), clinical findings (elderly male preponderance, fluctuating obstructive jaundice without pain, occasional extrapancreatic lesions, and favorable response to steroid therapy), and histopathological findings (dense infiltration of IgG4-positive plasma cells and T lymphocytes with fibrosis and obliterative phlebitis in various organs). It is apparent that elevation of serum IgG4 levels and infiltration of abundant IgG4-positive plasma cells into various organs are rather specific to AIP patients. We propose a new clinicopathological entity, "IgG4-related sclerosing disease", and suggest that AIP is a pancreatic lesion reflecting this systemic disease.

Recurrence of inflammatory pseudotumor in the distal bile duct: Lessons learned from a single case and reported cases

Inflammatory myofibroblastic tumors (IMTs) or inflammatory pseudotumors (IPs) have been extensively discussed in the literature. They are usually found in the lung and upper respiratory tract. However, reporting of cases involving the biliopancreatic region has increased over recent years. Immunohistochemical study of these lesions limited to the pancreatic head or distal bile duct seems to be compatible with those observed in a new entity called autoimmune pancreatitis, but usually intense fibrotic reaction (zonation) predominates producing a mass. When this condition is limited to the pancreatic head, the common bile duct might be involved by the inflammatory process and jaundice may occur often resembling adenocarcinoma of the pancreas. We have previously reported a case of IMT arising from the bile duct associated with autoimmune pancreatitis which is an extremely rare entity. Four years after Kaush-Whipple resection, radiological examination on routine follow-up revealed a tumor mass, suggesting local recurrence. Ultrasound-guided FNA confirmed our suspicious diagnosis. This present case, as others, suggests that persistent follow-up is necessary in order to prevent irreversible liver damage at this specific location.

Sclerosing cholecystitis associated with autoimmune pancreatitis

AIM: To evaluate the histopathological and radiological findings of the gallbladder in patients with autoimmune pancreatitis (AIP).

METHODS: The radiological findings of the gallbladder of 19 AIP patients were retrospectively reviewed. Resected gallbladders of 8 AIP patients were examined histologically and were immunostained with anti-IgG4 antibody. Controls consisted of gallbladders resected for symptomatic gallstones (n = 10) and those removed during pancreatoduodenectomy for pancreatic carcinoma (n = 10), as well as extrahepatic bile ducts and pancreases removed by pancreatoduodenectomy for pancreatic carcinoma (n = 10).

RESULTS: Thickening of the gallbladder wall was detected by ultrasound and/or computed tomography in 10 patients with AIP (3 severe and 7 moderate); in these patients severe stenosis of the extrahepatic bile duct was also noted. Histologically, thickening of the gallbladder was detected in 6 of 8 (75%) patients with AIP; 4 cases had transmural lymphoplasmacytic infiltration with fibrosis, and 2 cases had mucosal-based lymphoplasmacytic infiltration. Considerable transmural thickening of the extrahepatic bile duct wall with dense fibrosis and diffuse lymphoplasmacytic infiltration was detected in 7 patients. Immunohistochemically, severe or moderate infiltration of IgG4-positive plasma cells was detected in the gallbladder, bile duct, and pancreas of all 8 patients, but was not detected in controls.

CONCLUSION: Gallbladder wall thickening with fibrosis and abundant infiltration of IgG4-positive plasma cells is frequently detected in patients with AIP. We propose the use of a new term, sclerosing cholecystitis, for these cases that are induced by the same mechanism as sclerosing pancreatitis or sclerosing cholangitis in AIP.

Influence of steroid therapy on the course of diabetes mellitus in patients with autoimmune pancreatitis: findings from a nationwide survey in Japan

OBJECTIVE

The aim of this study was to estimate the number of autoimmune pancreatitis (AIP) patients in Japan and evaluate the influence of steroid therapy on the course of diabetes mellitus (DM) in AIP.

METHODS

A total of 2972 departments were randomly selected with hospital stratification throughout Japan. We sent a questionnaire asking the selected departments to report the number of patients who had visited their hospital in 2002 and who fulfilled the diagnostic criteria for AIP set by the Japan Pancreas Society. We then sent a second questionnaire asking for the details of the clinical course of DM, if any, and the treatments used for AIP.

RESULTS

The annual number of AIP in Japan was estimated as approximately 900 (95% confidence interval 670-1100) or 0.71 per 100,000 individuals in the Japanese population. In the second survey, 66.5% of the 167 patients of AIP were reported as being complicated with DM. Among the AIP patients with DM (n = 93), 52% of the patients started to show DM simultaneously with the onset of AIP, and 33% of the patients had DM before the onset of AIP. Following steroid therapy, 55% and 36% of these patient groups showed improvement of DM control, respectively. On the other hand, less than 20% of patients showed newly developed DM or showed exacerbation of DM control after steroid therapy. The older the patients were, the higher were the rates of new development or exacerbation of DM.

CONCLUSIONS

These findings indicated that steroid therapy has a beneficial effect on the clinical courses of DM in approximately half of AIP patients. However, it also has negative effect on glucose tolerance in some patients, particularly older patients, and thus, careful observation for involvement of DM should be required in AIP patients treated with steroids.

Endoscopic ultrasound guided fine needle aspiration biopsy of autoimmune pancreatitis: diagnostic criteria and pitfalls

Autoimmune pancreatitis (AIP) is a benign inflammatory disease of the pancreas that mimics pancreatic malignancy both clinically and radiologically. The fine needle aspiration biopsy (FNAB) features of AIP have not previously been documented. We report our experience with AIP, highlight pitfalls, and perform a comprehensive analysis of the cytomorphologic features of this condition. We identified 16 patients with AIP, initially evaluated by endoscopic ultrasound (EUS)-guided FNAB, 11 of whom subsequently underwent a pancreatoduodenectomy. We compared these to a cohort of EUS-guided aspirates from ductal carcinoma of the pancreas (n = 16) and chronic pancreatitis, not otherwise specified (NOS) (n = 19). On all 51 cases, we semiquantitatively evaluated presence and atypia of ductal cells, presence and cellularity of stromal fragments, and inflammatory cells, type and distribution. Fifty percent (8 of 16) of the AIP cases presented as obstructive jaundice. EUS and CT scan showed mass lesions in 10 and 6 cases, respectively. There were three false-positive cytologic diagnoses, an adenocarcinoma, a solid-pseudopapillary tumor and a mucinous neoplasm. Ductal epithelium was inconspicuous and was seen in 6 cases. The FNAB samples showed background lymphocytes in three AIP cases, a feature absent in the control cohort. Stromal fragments with embedded lymphocytes (greater than 30 per 60x) were seen in 37.5% of AIP cases and only rarely with adenocarcinoma (12.5%) and pancreatitis, NOS (0%). The cellularity of stromal fragments was significantly higher in AIP than in the control group. The presence of stromal fragments of high cellularity with a lymphoid infiltrate in conjunction with clinical and radiology findings could potentially both establish a diagnosis of AIP and exclude carcinoma, thus preventing pancreatic resection.

Involvement of pancreatic and bile ducts in autoimmune pancreatitis

AIM: To examine the involvement of the pancreatic and bile ducts in patients with autoimmune pancreatitis.

METHODS: Clinical and cholangiopancreatographic findings of 28 patients with autoimmune pancreatitis were evaluated. For the purposes of this study, the pancreatic duct system was divided into three portions: the ventral pancreatic duct; the head portion of the dorsal pancreatic duct; and the body and tail of the dorsal pancreatic duct.

RESULTS: Both the ventral and dorsal pancreatic ducts were involved in 24 patients, while in 4 patients only the dorsal pancreatic duct was involved. Marked stricture of the bile duct was detected in 20 patients and their initial symptom was obstructive jaundice. Six patients showed moderate stenosis to 30%-40% of the normal diameter, and the other two patients showed no stenosis of the bile duct. Although marked stricture of the bile duct was detected in 83% (20/24) of patients who showed narrowing of both the ventral and dorsal pancreatic ducts, it was not observed in the 4 patients who showed involvement of the dorsal pancreatic duct alone (P = 0.0034).

CONCLUSION: Both the ventral and dorsal pancreatic and bile ducts are involved in patients with autoimmune pancreatitis.