Diagnosis and management of autoimmune pancreatitis: Experience from China

Clinical features of IgG4-associated autoimmune pancreatitis and factors related to its recurrence

BACKGROUND

IgG4-associated autoimmune pancreatitis (IgG4-AIP) is a kind of autoimmune-mediated pancreatitis. The clinical manifestations of IgG4-AIP are not specific and the differential diagnosis is often difficult, and the indications and course of glucocorticoid treatment for the disease are still controversial. The aim of this study was to improve the understanding, diagnosis, and treatment of the disease by analyzing the clinical characteristics of the disease, and to reduce the recurrence rate of the disease by analyzing the factors related to its recurrence.

AIM

To investigate the clinical features, therapeutic efficacy, and recurrence of IgG4-AIP.

METHODS

The clinical data of 46 patients with IgG4-AIP were analyzed retrospectively.

RESULTS

The male to female ratio of IgG4-AIP patients was 10.5:1. The most common clinical manifestation was obstructive jaundice. Approximately 52.1% of patients had extrapancreatic organ involvement, with the most commonly affected extrapancreatic organ being the bile duct. The vast majority (91.3%) of patients had higher serum IgG4 levels than normal. The imaging findings were diffuse swelling or local enlargement of the pancreas with stricture of the biliary and pancreatic ducts. The majority (81.2%) of patients underwent pancreatic biopsy under the guidance of endoscopic ultrasonography. Typical pathological findings included fibrous tissue proliferation, lymphocyte and plasma cell infiltration, and acinar atrophy of the pancreas. Half of the patients showed a large number of IgG4 positive plasma cells as revealed by immunohistochemistry. Glucocorticoids were effective for IgG4-AIP, but 36.8% of the patients relapsed after remission, and 71.4% relapsed after stopping glucocorticoids. Logistic regression analysis showed that the risk factors for recurrence were pancreatic portal hypertension and involvement of extra-pancreatic organs. Low-dose glucocorticoid maintenance therapy could prevent recurrence.

CONCLUSION

Due to the lack of specific clinical manifestation, IgG4-AIP is easily misdiagnosed as pancreatic cancer. The main manifestations of IgG4-AIP are increased serum IgG4 level, diffuse or local swelling of pancreas with biliopancreatic duct stricture, multiple organ involvement, IgG4 positive plasma cell infiltration, tissue fibrosis, and response to treatment with glucocorticoids. The risk factors for recurrence of IgG4-AIP are pancreatic portal hypertension and extrapancreatic organ involvement. Low-dose glucocorticoid maintenance therapy can prevent recurrence.

Characteristics of mass-forming autoimmune pancreatitis commonly misdiagnosed as a malignant tumor

Objective

This study aimed to explore the clinical characteristics and differential diagnosis of patients with autoimmune pancreatitis (AIP) and pancreatic cancer to prevent misdiagnosis and mistreatment.

Methods

The clinical data of patients with AIP with suspected pancreatic or bile duct malignancy and pancreatic cancer were retrospectively analyzed. The risk factors and the diagnostic value of IgG4 and Tbil levels before treatment for AIP was investigated. Moreover, the imaging features and response to hormone therapy were analyzed.

Results

AIP was commonly observed in men. Compared to patients with pancreatic cancer, the incidence of poor appetite and weight loss and carbohydrate antigen 19-9 (CA19-9) level was lower in patients with AIP, while the immunoglobulin G4 (IgG4) level was higher (p < 0.05). After treatment, the IgG4 and CA19-9 levels in patients with AIP were decreased (p < 0.001). IgG4 level before treatment (OR = 2.452, 95%CI: 1.180-5.096, P = 0.016) and total bilirubin (Tbil) level before treatment (OR = 0.992, 95%CI: 0.985-0.998, P = 0.013) were independent risk factors of AIP. Furthermore, the diagnostic value of IgG4 level before treatment, Tbil level before treatment, IgG4/Tbil before treatment, and a combination of these indicators was high. Moreover, 15 (68.18%) patients with AIP had space-occupying lesions of the pancreas, and 16 (72.73%) had autoimmune cholangitis. Most patients with AIP were sensitive to hormone therapy.

Conclusions

The Tbil and IgG4 levels, imaging findings, and hormone therapy reactivity could differentiate AIP from pancreatic cancer. A combination of IgG4, Tbil, and IgG4/Tbil before treatment might be a promising diagnostic biomarker for AIP.

Autoimmune pancreatitis: What we know so far

Autoimmune pancreatitis (AIP) is a rare, often‐missed disease that involves inflammation of the pancreas and strictures of the pancreatic duct. Its prevalence and incidence in the United States remain scarce. The disease has a varied presentation and often mimics pancreatic malignancy, which can make the diagnosis challenging. Most patients have an excellent response to corticosteroid therapy. Immunomodulators may be used in some cases. Rituximab is an effective, emerging treatment in steroid‐refractory cases. This study aims to review the two distinct types of AIP and provide a detailed analysis of the diagnostic approach and treatment modalities.

Autoimmune Pancreatitis after a Seven-Year History of Suspicious Pancreatic Cancer

In this case report, we present a case of autoimmune pancreatitis (AIP) diagnosis in a patient after a 7-year history of suspicious pancreatic cancer. Kim's and Japanese criteria were used to diagnose AIP. Our case avoided undesirable invasive procedures and recovered thanks to the proper diagnosis and timely treatment with prednisone. Early and accurate diagnosis of AIP, in this case, had a significant impact on the treatment and prognosis process.

From Pathogenesis, Clinical Manifestation, and Diagnosis to Treatment: An Overview on Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis which is autoimmune mediated. The international consensus diagnostic criteria (ICDC) 2011 proposed two types of AIP: type I is associated with histological pattern of lymphoplasmacytic sclerosing pancreatitis (LPSP), characterized by serum IgG4 elevation, whereas type 2 is named idiopathic duct-centric pancreatitis (IDCP), with granulocytic epithelial lesion (GEL) and immunoglobulin G4 (IgG4) negative. The pathogenic mechanism is unclear now; based on genetic factors, disease specific or related antigens, innate and adaptive immunity may be involved. The most common clinical manifestations of AIP are obstructive jaundice and upper abdominal pain. The diagnosis can be made by a combination of parenchymal and ductal imaging, serum IgG4 concentrations, pancreatic histology, extrapancreatic disease, and glucocorticoid responsiveness according to ICDC 2011. Because of the clinical and imaging similarities with pancreatic cancer, general work-up should be done carefully to exclude pancreatic malignant tumor before empirical trial of glucocorticoid treatment. Glucocorticoid is the most common drug for AIP to induce remission, while there still exists controversy on steroid maintenance and treatment for relapse. Further studies should be done to identify more specific serum biomarkers for AIP, the pathogenic mechanisms, and the treatment for relapse.

IgG4-related retroperitoneal fibrosis: a newly characterized disease

Retroperitoneal fibrosis (RPF) is a rare disease characterized by chronic, nonspecific inflammatory and sclerotic or fibrotic tissue in the periaortic or periiliac retroperitoneum that encases adjacent structures. There will be a series of clinical manifestations once the proliferated fibrous tissues encase the abdominal aorta, iliac arteries and urinary duct. RPF is generally divided into two types: idiopathic retroperitoneal fibrosis (IRPF) without identified pathogenesis, making up about two-thirds of cases, and secondary retroperitoneal fibrosis. Recent studies on Immunoglobulin G4-related disease (IgG4-RD) reveal that abundant infiltration of IgG4 positive plasma cells is found in biopsies on the mass of RPF of some IRPF patients, which is identified as one spectrum of IgG4-RD and is named IgG4-related RPF. IgG4-related RPF is often misdiagnosed as retroperitoneal visceral malignancy and is treated with surgery. In addition, because of its good response to glucocorticoid, early detection and treatment is important. We review the definition, epidemiology, clinical features, diagnostic criteria, treatment and prognosis of IgG4-related RPF in this article to raise awareness of this newly characterized disease.

Diagnostic Performance of Serum IgG4 Levels in Patients With IgG4-Related Disease

The aim of this study is to study the clinical features and diagnostic performance of IgG4 in Chinese populations with IgG4-related diseases (IgG4-RDs).The medical records of 2901 adult subjects who underwent serum IgG4 level tests conducted between December 2007 and May 2014 were reviewed.Serum concentrations of IgG4 were measured in 2901 cases, including 161 (5.6%) patients with IgG4-RD and 2740 (94.4%) patients without IgG4-RD (non-IgG4-RD group). The mean age of the IgG4-RD patients was 58.4 ± 16.1 years (range: 21-87), and 48 (29.8%) were women. The mean serum IgG4 level was significantly much higher in IgG4-RD patients than in non-IgG4-RD (1062.6 vs 104.3 mg/dL, P < 0.001) participants. For IgG4 >135 mg/dL, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR)+, and LR- were 86%, 77%, 18%, 99%, 3.70, and 0.19, respectively. When the upper limit of normal was doubled for an IgG4 >270 mg/dL, the corresponding data were 75%, 94%, 43%, 98%, 12.79, and 0.26, respectively. For IgG4 >405 mg/dL (tripling the upper limit of normal), the corresponding data were 62%, 98%, 68%, 98%, 37.00, and 0.39, respectively. When calculated according to the manufacturer's package insert cutoff (>201 mg/dL) for the diagnosis of IgG4-RD, the corresponding sensitivity, specificity, PPV, NPV, LR+, and LR- were 80%, 89%, 29%, 99%, 7.00, and 0.23, respectively. For IgG4 >402 mg/dL (>2× the upper limit of the normal range), the corresponding data were 62%, 98%, 68%, 98%, 36.21, and 0.39, respectively. For IgG4 >603 mg/dL (>3× the upper limit of the normal range), the corresponding data were 50%, 99%, 84%, 97%, 90.77 and 0.51, respectively. The optimal cutoff value of serum IgG4 (measured by nephelometry using a Siemens BN ProSpec instrument and Siemens reagent) for the diagnosis of IgG4-RD was 248 mg/dL, the sensitivity and specificity were 77.6% and 92.8%, respectively.The present study demonstrated that 2 or 3 times the upper limit of the manufacturer's reference range of the IgG4 level was a useful marker for the diagnosis of various types of IgG4-RD and the optimal cutoff level was 248 mg/dL.

Diagnosis and Treatment of Autoimmune Pancreatitis in China: A Systematic Review

AIMS

To provide comprehensive data on the diagnosis and treatment of autoimmune pancreatitis (AIP) patients in China.

DESIGN

A systematic review.

METHODS

All clinical studies concerning AIP from China published between January 2006 and June 2014 were retrospectively reviewed and analyzed.

RESULTS

A total of 26 original articles involving 706 AIP patients were included with an estimated proportion of type 2 AIP as 4.7%. In the 706 AIP patients, the range of mean/median age was 48.6-67.0 years old and the male to female ratio was 4.47:1. The common presentations included obstructive jaundice (pooled rate: 63.4%, 95%CI: 55.4%-71.0%) and abdominal symptoms (pooled rate: 62.3%, 95%CI: 52.4%-71.7%). Biliary involvement was the most common extrapancreatic manifestations, especially the lower part of the common bile duct (pooled rate: 62.3%, 95%CI: 49.9%-73.9%). According to the imaging examinations, 53.8% and 41.6% patients were classified into focal-type and diffuse-type, respectively. Notably, upstream pancreatic duct dilatation was found in parts of patients (pooled rate: 13.8%, 95%CI: 6.6%-23.1%). The levels of serum IgG4 were elevated in most patients (pooled rate: 86.0%, 95%CI: 74.2%-94.6%). Nearly three tenths AIP patients received surgery (pooled rate: 29.7%, 95%CI: 18.1%-42.8%) due to mimicked malignancy. Steroid treatment was given to 78.4% patients (95%CI: 65.3%-89.1%) with a pooled remission rate of 96.2% (95%CI: 94.0%-97.9%). The pooled relapse rate was 13.8% (95%CI: 7.2%-22.0%) with the mean follow-up time ranging from 12 to 45 months.

CONCLUSION

Type 1 is the predominant type of Chinese AIP patients and the clinical features, diagnostic modalities and therapeutic regimen were similar with those in other countries. Knowledge of AIP should be more widespread to avoid unnecessary surgery.

Diagnosis and treatment of autoimmune pancreatitis: experience with 100 patients

BACKGROUND

Autoimmune pancreatitis (AIP) is increasingly recognized as a unique subtype of pancreatitis. This study aimed to analyze the diagnosis and treatment of AIP patients from a tertiary care center in China.

METHODS

One hundred patients with AIP who had been treated from January 2005 to December 2012 in our hospital were enrolled in this study. We retrospectively reviewed the data of clinical manifestations, laboratory tests, imaging examinations, pathological examinations, treatment and outcomes of the patients.

RESULTS

The median age of the patients at onset was 57 years (range 23-82) with a male to female ratio of 8.1:1. The common manifestations of the patients included obstructive jaundice (49 patients, 49.0%), abdominal pain (30, 30.0%), and acute pancreatitis (11, 11.0%). Biliary involvement was one of the most extrapancreatic manifestations (64, 64.0%). Fifty-six (56.0%) and 43 (43.0%) patients were classified into focal-type and diffuse-type respectively according to the imaging examinations. The levels of serum IgG and IgG4 were elevated in 69.4% (43/62) and 92.0% (69/75) patients. Pathological analysis of specimens from 27 patients supported the diagnosis of lymphoplasmacytic sclerosing pancreatitis, and marked (>10 cells/HPF) IgG4 positive cells were found in 20 (74.1%) patients. Steroid treatment and surgery as the main initial treatments were given to 41 (41.0%) and 28 (28.0%) patients, respectively. The remission rate after the initial treatment was 85.0%. Steroid was given as the treatment after relapse in most of the patients and the total remission rate at the end of follow-up was 96.0%.

CONCLUSIONS

Clinical manifestations, laboratory tests, imaging and pathology examinations in combination could increase the diagnostic accuracy of AIP. Steroid treatment with an initial dose of 30 or 40 mg prednisone is effective and safe in most patients with AIP.

Amendment of the Japanese Consensus Guidelines for Autoimmune Pancreatitis, 2013 III. Treatment and prognosis of autoimmune pancreatitis

The standard treatment for autoimmune pancreatitis (AIP) is steroid therapy, although some patients improve spontaneously. Indications for steroid therapy in AIP patients are symptoms such as obstructive jaundice, abdominal pain, back pain, and the presence of symptomatic extrapancreatic lesions. Prior to steroid therapy, obstructive jaundice should be managed by biliary drainage, and blood glucose levels should be controlled in patients with diabetes mellitus. The recommended initial oral prednisolone dose for induction of remission is 0.6 mg/kg/day, which is administered for 2-4 weeks. The dose is then tapered by 5 mg every 1-2 weeks, based on changes in clinical manifestations, biochemical blood tests (such as liver enzymes and IgG or IgG4 levels), and repeated imaging findings (US, CT, MRCP, ERCP, etc.). The dose is tapered to a maintenance dose (2.5-5 mg/day) over a period of 2-3 months. Cessation of steroid therapy should be based on the disease activity in each case. Termination of maintenance therapy should be planned within 3 years in cases with radiological and serological improvement. Re-administration or dose-up of steroid is effective for treating AIP relapse. Application of immunomodulatory drugs is considered for AIP patients who prove resistant to steroid therapy. The prognosis of AIP appears to be good over the short-term with steroid therapy. The long-term outcome is less clear, as there are many unknown factors, such as relapse, pancreatic exocrine or endocrine dysfunction, and associated malignancy.

Retrospective study of steroid therapy for patients with autoimmune pancreatitis in a Chinese population

AIM: To explore the optimal steroid therapeutic strategy for autoimmune pancreatitis (AIP).

METHODS: This study was conducted retrospectively in two large institutions in China. Patients with clinically, radiologically and biochemically diagnosed AIP were enrolled. The performed radiological investigations and biochemical tests, the regimen of the given steroid treatment, remission and relapse whether with and without steroid therapy were analyzed.

RESULTS: Twenty-eight patients with AIP received steroid treatment, while 40 patients were treated surgically by pancreatoduodenectomy, distal pancreatectomy and choledochojejunostomy, radiofrequency ablation for the enlarged pancreatic head, percutaneous transhepatic biliary drainage and endoscopic biliary drainage. The starting oral prednisolone dose was 30 mg/d in 18 (64.3%) patients and 40 mg/d in 10 (35.7%) patients administered for 3 wk. The remission rate of AIP patients with steroid treatment (96.4%) was significantly higher than in those without steroid treatment (75%). Maintenance therapy (oral prednisolone dose 5 mg/d) was performed after remission for at least 6-12 mo to complete the treatment course. Similarly, the relapse rate was significantly lower in AIP patients with steroid treatment (28.6%) than in those without steroid treatment (42.5%). Steroid re-treatment was effective in all relapsed patients with or without steroid therapy.

CONCLUSION: Steroid therapy should be considered in all patients with active inflammatory phase of AIP. However, the optimal regimen still should be trailed in larger numbers of patients with AIP.

Retroperitoneal fibrosis associated with immunoglobulin G4-related disease

Retroperitoneal fibrosis is a rare disease characterized by the development of inflammation and fibrosis in the soft tissues of the retroperitoneum and other abdominal organs. Retroperitoneal fibrosis can be of 2 types: idiopathic and secondary. The recently advocated concept and diagnostic criteria of immunoglobulin G4 (IgG4)-related disease, derived from research on autoimmune pancreatitis (AIP), has led to widespread recognition of retroperitoneal fibrosis as a condition caused by IgG4-related disease. We now know that previously diagnosed idiopathic retroperitoneal fibrosis includes IgG4-related disease; however, the actual prevalence is unclear. Conversely, some reports on AIP suggest that retroperitoneal fibrosis is concurrently found in about 10% of IgG4-related disease. Because retroperitoneal fibrosis has no specific symptoms, diagnosis is primarily based on diagnostic imaging (computed tomography and magnetic resonance imaging), which is also useful in evaluating the effect of therapy. Idiopathic retroperitoneal fibrosis can occur at different times with other lesions of IgG4-related disease including AIP. Thus, the IgG4 assay is recommended to diagnose idiopathic retroperitoneal fibrosis. High serum IgG4 levels should be treated and monitored as a symptom of IgG4-related disease. The first line of treatment for retroperitoneal fibrosis is steroid therapy regardless of its cause. For patients with concurrent AIP, i.e., IgG4-related retroperitoneal fibrosis, the starting dose of steroid is usually 30-40 mg/d. The response to steroid therapy is generally favorable. In most cases, the pancreatic lesion and retroperitoneal fibrosis improve after the initial treatment. However, the epidemiology, treatment for recurring retroperitoneal fibrosis, and long-term prognosis are still largely unknown. Further analysis of such cases and research are necessary.

Autoimmune pancreatitis mimicking pancreatic cancer

Context:

Autoimmune pancreatitis is a particular type of pancreatitis of presumed autoimmune etiology, it is an entity distinct from all others forms of chronic pancreatitis, characterized by clinical, histopathological, radiographic, serologic and therapeutic features. This benign disease resembles pancreatic carcinoma both clinically and radiographically.

Case Report:

A 27-year-old man presented with obstructive jaundice and evocative image of pancreatic tumor. A pancreaticoduodenectomy (Whipple operation) was performed and pathological examination of the specimen diagnosed AIP. Patient responded well to a course of corticosteroids with resolution of clinical and biological disorders.

Conclusion:

Accurate and timely diagnosis of autoimmune pancreatitis is particularly important because steroid therapy is effective and pancreatic resection is not necessary.

Autoimmune pancreatitis: an update on classification, diagnosis, natural history and management

Autoimmune Pancreatitis (AIP) is a recently recognized chronic fibro-inflammatory disease of the pancreas. Although rare, its recognition continues to increase worldwide. Patients often present with painless obstructive jaundice mimicking pancreatic cancer. Two subtypes of AIP are known-type 1 is a multi-organ disease associated with IgG4; type 2 appears to be a pancreas-specific disorder. Dramatic response to steroid treatment is characteristic of both forms. A non-invasive diagnosis of type 1 AIP may be possible using diagnostic criteria (in ~70% cases) while diagnosis of type 2 requires histology. These subtypes differ in natural history- type 1 often relapses while initial reports suggest that type 2 does not. Long term complications include endocrine and exocrine insufficiency and in case of type 1, disease relapses and complications from extra-pancreatic involvement. Neither form affects long term survival. The treatment and follow-up guidelines continue to evolve with our increasing experience in AIP.

Autoimmune pancreatitis characterized by predominant CD8+ T lymphocyte infiltration

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis characterized by prominent lymphocyte infiltration and pancreatic fibrosis resulting in organ dysfunction. The pathogenesis and pathology of AIP remain unknown. A 64-year-old Chinese man presented with symptoms and signs of bile duct obstruction diffuse enlargement of the head of pancreas, elevated IgG levels, and negative autoimmune antibody responses. A pylorus-preserving pancreatoduodenectomy was performed and a pancreatic tumor was suspected. However, periductal lymphoplasmacytic infiltration and fibrosis were found in the head of pancreas and nearby organs instead of tumor cells. Four months after surgery, the patient was readmitted because of reoccurrence of severe jaundice and sustained abdominal distension. Prednisone 30 mg/d was administered orally as an AIP was suspected. One and a half months later, the symptoms of the patient disappeared, and globulin, aminotransferase and bilirubin levels decreased significantly. Over a 9-mo follow-up period, the dose of prednisone was gradually decreased to 10 mg/d and the patient remained in good condition. We further demonstrated dominant CD3+/CD8+ populations, CD20+ cells and a few CD4+ cells in the pancreatic parenchyma, duodenum and gallbladder wall by immunohistochemical assay. This AIP case presented with significant CD8+ T lymphocyte infiltration in the pancreas and extra-pancreatic lesions, indicating that this cell population may be more important in mediating AIP pathogenesis than previously known and that AIP might be a poorly defined autoimmune disease with heterogeneous pathogenesis.

Clinical characteristics of 327 Asian patients with autoimmune pancreatitis based on Asian diagnostic criteria

OBJECTIVES

To clarify the clinical and pathophysiological characteristics of autoimmune pancreatitis (AIP) in Asia.

METHODS

A retrospective, actual situation survey of AIP diagnosed by Asian criteria was conducted in 10 centers of Japan, Korea, Taiwan, China, and India.

RESULTS

A total of 327 AIP cases (258 male and 69 female subjects; average age, 60.0 years) were enrolled. Obstructive jaundice was the most frequent initial symptom (46%-74%), followed by weight loss (4%-51%) and abdominal pain (19%-44%). Diffuse swelling of the pancreas was frequent in Japan (64%) and Korea (81%), but segmental swelling of the pancreas was more frequent in Taiwan (70%) and China (72%) (P < 0.01). Serum immunoglobulin G4 levels were elevated in 58%-100% of cases in Japan, Korea, and Taiwan. Pathologically, almost all AIPs in Asia were lymphoplasmacytic sclerosing pancreatitis. Sclerosing cholangitis was the most frequent extrapancreatic lesion (60%-81%). Steroid therapy was a major and effective therapeutic strategy in Japan, Korea, and Taiwan. However, the rate of resection or bypass operation was higher in Taiwan (40%) and China (72%) (P < 0.01).

CONCLUSIONS

Features of AIP are fundamentally similar in Japan, Korea, Taiwan, and China. Knowledge of emerging AIP should be more widespread in Asia to avoid unnecessary operation.

Review article: autoimmune pancreatitis - management of an emerging disease

BACKGROUND

Autoimmune pancreatitis is a steroid-responsive inflammatory pancreatic disease considered to be part of an immunoglobulin G4 (IgG4)-associated systemic disease.

AIM

To review the management of autoimmune pancreatitis.

METHODS

We conducted a PubMed search using the following key words: autoimmune pancreatitis, IgG4-associated systemic disease, IgG4-associated cholangitis, diagnosis, natural history, treatment.

RESULTS

Although there are reports of spontaneous resolution of autoimmune pancreatitis, steroids have been shown to be effective in inducing remission, reducing the frequency of relapse and that of long-term unfavourable events compared to historical controls. There are no randomised data on autoimmune pancreatitis treatment. Oral steroids are used for induction of remission. Reported response results are excellent with variable proportions of patients achieving remission in different studies. After a period of 2-4 weeks, steroids are tapered and usually withdrawn within several months, although long-term maintenance therapy for all autoimmune pancreatitis patients has also been proposed. Disease relapse occurs in more than 40% of patients and can be effectively treated with additional immunosuppression, including azathioprine.

CONCLUSIONS

Steroids are effective in inducing remission and in treating relapse in patients with autoimmune pancreatitis. Randomised trials on autoimmune pancreatitis therapy are lacking. To date, questions concerning the timing, choice and duration of long-term immunosuppression remain unanswered.

Outcome of patients with type 1 or 2 autoimmune pancreatitis

OBJECTIVES

Autoimmune pancreatitis (AIP) is better described than before, but there is still no international consensus for definition, diagnosis, and treatment. Our aims were to analyze the short- and long-term outcome of patients with focus on pancreatic endocrine and exocrine functions, to search for predictive factors of relapse and pancreatic insufficiency, and to compare patients with type 1 and type 2 AIP.

METHODS

All consecutive patients followed up for AIP in our center between 1999 and 2008 were included. Two groups were defined: (a) patients with type 1 AIP meeting HISORt (Histology, Imaging, Serology, Other organ involvement, and Response to steroids) criteria; (b) patients with definitive/probable type 2 AIP including those with histologically confirmed idiopathic duct-centric pancreatitis ("definitive") or suggestive imaging, normal serum IgG4, and response to steroids ("probable"). AIP-related events and pancreatic exocrine/endocrine insufficiency were looked for during follow-up. Predictive factors of relapse and pancreatic insufficiency were analyzed.

RESULTS

A total of 44 patients (22 males), median age 37.5 (19-73) years, were included: 28 patients (64%) with type 1 AIP and 16 patients (36%) with type 2 AIP. First-line treatment consisted of steroids or pancreatic resection in 59 and 27% of the patients, respectively. Median follow-up was 41 (5-130) months. Steroids were effective in all treated patients. Relapse was observed in 12 patients (27%), after a median delay of 6 months (1-70). Four patients received azathioprine because of steroid resistance/dependence. High serum IgG4 level, pain at time of diagnosis, and other organ involvement were associated with relapse (P<0.05). At the end point, pancreatic atrophy was observed in 35% of patients. Exocrine and endocrine insufficiencies were present in 34 and 39% of the patients, respectively. At univariate analysis, no factor was associated with exocrine insufficiency, although female gender (P=0.04), increasing age (P=0.006), and type 1 AIP (P=0.001) were associated with the occurrence of diabetes. Steroid/azathioprine treatment did not prevent pancreatic insufficiency. Type 2 AIP was more frequently associated with inflammatory bowel disease than type 1 AIP (31 and 3%, respectively), but relapse rates were similar in both groups.

CONCLUSIONS

Relapse occurs in 27% of AIP patients and is more frequent in patients with high serum IgG4 levels at the time of diagnosis. Pancreatic atrophy and functional insufficiency occur in more than one-third of the patients within 3 years of diagnosis. The outcome of patients with type 2 AIP, a condition often associated with inflammatory bowel disease, is not different from that of patients with type 1 AIP, except for diabetes.

Eosinophilia and allergic disorders in autoimmune pancreatitis

OBJECTIVES

In autoimmune pancreatitis (AIP), the prevalence, interrelationships, and significance of peripheral eosinophilia, allergic disorders, and eosinophil infiltration in the pancreas remain unclear.

METHODS

From medical records, we obtained data on peripheral eosinophil counts at presentation and follow-up, and clinical diagnoses of allergic disorders in 97 AIP patients (78 type 1 and 19 type 2), which were compared with matched healthy controls. Available pancreatic histologic specimens were graded for eosinophils. Peripheral eosinophilia was defined as counts >0.5×10(9) per liter. We examined nature of and association between these parameters in AIP.

RESULTS

Among 78 type 1 AIP patients (mean age 62±14 years, 77% men), peripheral eosinophilia at presentation was diagnosed in 12% and allergic disorders in 15% (vs. 0 and 4% in controls, P=0.0004 and 0.006, respectively). Allergic disorders were observed in 27 and 11% of type 1 AIP with and without eosinophilia, respectively (P=0.08). Patients with and without peripheral eosinophilia were similar in clinical profile. Moderate-to-severe eosinophil infiltration was present in 67% of pancreas resection specimens and did not correlate with peripheral eosinophilia. Type 2 AIP did not differ from type 1 AIP in any of these parameters.

CONCLUSIONS

Peripheral eosinophilia, allergic disorders, and pancreatic eosinophil infiltration are associated with AIP. Eosinophilia in AIP may not reflect an allergic phenomenon, but appears to be consistent with autoimmune mechanism.

Remission and relapse of autoimmune pancreatitis: focusing on corticosteroid treatment

Autoimmune pancreatitis (AIP) is a type of chronic pancreatitis characterized by swelling of the pancreas, narrowing of the main pancreatic duct, elevation of serum immunoglobulin G or G4 level or presence of several autoantibodies, or lymphoplasmacytic infiltration and fibrosis in the pancreas. However, the pathogenesis of AIP remains unclear, and the natural history and long-term prognosis of AIP are little known. Oral corticosteroid therapy for AIP is recommended. The absolute indications for steroid therapy for AIP are bile duct stenosis and accompanying systemic disease such as retroperitoneal fibrosis and diabetes mellitus. The dosage for remission induction is 30 to 40 mg/d for 1 to 2 months. The remission maintenance is needed to prevent relapse, and 5 to 10 mg/d for at least 6 months is recommended in patients who do not have complete remission. When relapse occurs, the dose used at remission induction can be readministered. Herein, we discuss remission and relapse of AIP, focusing on corticosteroid treatment to help clinicians care for patients with AIP and to help make an ideal treatment protocol of AIP through a review of published data. We tried to define remission and relapse of AIP to help investigate the natural course of AIP.

Evaluation and management of autoimmune pancreatitis: experience at a large US center

OBJECTIVES

Autoimmune pancreatitis (AIP) is increasingly recognized as a form of chronic pancreatitis. Systematic evaluation and management of AIP in the United States is reported only from one center. Our aim was to review the evaluation and management of AIP at a large tertiary center.

METHODS

We retrospectively reviewed information on demographics, clinical presentation, laboratory and imaging findings, extrapancreatic involvement, treatment response, and recurrence in 26 patients with AIP treated at the University of Pittsburgh Medical Center from 1998 to 2007.

RESULTS

The median age at presentation was 62.5 years (range: 23-86), 65% were men, and 88% were Caucasians. The most common presentation included new-onset mild abdominal pain (65%), jaundice (62%), and weight loss (42%). Pancreatic mass, enlargement, or prominence on imaging was present in 85% of the patients. Serum IgG4 (immunoglobulin-4) was elevated (>140 mg/dl) in 44% (8/18) at presentation. The most common extrapancreatic finding was extrapancreatic/intrahepatic biliary strictures (35%). Peri-pancreatic vascular complications were noted in 23% of the patients. Six patients underwent partial or complete pancreatectomy. Partial or complete response was observed for initial steroid treatment in 19 patients and for methotrexate in 1 patient. Recurrences were common, especially in patients with extrapancreatic manifestations, and usually responded to a combination of steroids and azathioprine. Any one of the commonly used diagnostic criteria (Mayo Clinic's HISORt criteria, the Japanese Pancreas Society criteria, Korean diagnostic criteria) was fulfilled in 85% of cases.

CONCLUSIONS

In this second major US series, we confirm several findings previously reported in AIP. Our study highlights the presence of vascular complications in a subset of patients with AIP. The current diagnostic criteria may not identify all AIP patients.

Autoimmune pancreatitis: differences between the focal and diffuse forms in 87 patients

OBJECTIVES

Autoimmune pancreatitis (AIP) is a particular type of chronic pancreatitis that can be classified into diffuse and focal forms. The aim of this study was to analyze clinical and instrumental features of patients suffering from the diffuse and focal forms of AIP.

METHODS

AIP patients diagnosed between 1995-2008 were studied.

RESULTS

A total of 87 AIP patients (54 male and 33 female patients, mean age 43.4+/-15.3 years) were studied. Focal-type AIP was diagnosed in 63% and diffuse-type in 37%. Association with autoimmune diseases was observed in 53% of cases, the most common being ulcerative colitis (30%). Serum levels of IgG4 exceeded the upper normal limits (135 mg/dl) in 66% of focal AIP and in 27% of diffuse AIP (P=0.006). All patients responded to steroids. At recurrence non-steroid immunosuppressive drugs were successfully used in six patients. Recurrences were observed in 25% of cases, and were more frequent in focal AIP (33%) than in diffuse AIP (12%) (P=0.043), in smokers than in non-smokers (41% vs. 15%; P=0.011), and in patients with pathological serum levels of IgG4 compared to those with normal serum levels (50% vs. 12%; P=0.009). In all, 23% of the patients underwent pancreatic resections. Among patients with focal AIP, recurrences were observed in 30% of operated and in 34% of not operated patients.

CONCLUSIONS

Focal-type and diffuse-type AIP differ as regards clinical symptoms and signs. Recurrences occur more frequently in focal AIP than in diffuse AIP. The use of non-steroid immunosuppressants may be a therapeutic option in relapsing AIP.

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.

[From the chronic pancreatitis to chronic pancreatites]

Chronic alcohol intake accounts for 60-90% of the cases of chronic pancreatitis, but other etiologies have been recognized and described in the very recent years. Genetic causes include mutations of the cationic trypsinogen gene PRSS1 (100 families in France), of its inhibitor SPINK1 and of the CFTR gene involved in cystic fibrosis. Auto-immune pancreatitis is often part of an "IgG4-related systemic disease" involving the biliary tract, the salivary glands, the retroperitoneum and/or the kidneys. Diagnostic criteria are now well-defined (HISORt of the Mayo Clinic), with ductal and parenchymal lesions on imaging that may mimick pancreatic adenocarcinoma. Corticoids are efficacious but recurrences are frequent and long-term outcome is still poorly known.

A variant form of autoimmune pancreatitis successfully treated by steroid therapy, accompanied by von Meyenburg complex

Diagnostic criteria for autoimmune pancreatitis (AIP) have been proposed and used clinically because, despite its unique clinicopathological features, AIP does not have disease-specific serological tests for confirmation. However, diagnosis of a patient with pancreatic lesions mimicking cancer who deviates from these diagnostic criteria is still difficult. We present herein a patient with a variant form of AIP successfully diagnosed by fine-needle biopsy, whose response to steroid therapy was excellent. A 55-year-old Japanese man was admitted to hospital because of jaundice and pancreatic head mass. AIP was considered as one of the differential diagnoses; however, as the patient showed neither pancreatic duct narrowing nor immunological abnormalities, he did not meet the Japanese diagnostic criteria for AIP. Histopathology of the pancreatic mass demonstrated abundant infiltration by lymphocytes and interstitial fibrosis, which suggested AIP. Immunoreaction to IgG4, which is supposed to be specific to AIP, was not observed; however, response to subsequent prednisolone therapy was good, with dramatic pancreatic head mass regression. Aside from the pancreatic head mass, diffusely spreading small lesions were observed throughout the liver. The likelihood of a potential association with extrapancreatic lesions of AIP was considered and led us to carry out a liver biopsy, which revealed biliary hamartoma, also called von Meyenburg complex (VMC). As IgG4-positive plasma cell infiltration was not demonstrated in the hamartomatous regions, the hepatic condition was thought to have occurred incidentally; however, to the best of our knowledge, this is the first report in which the association between AIP and VMC was investigated and discussed.