Diagnostic criteria for autoimmune chronic pancreatitis

Clinical characteristics and outcomes of autoimmune pancreatitis based on serum immunoglobulin G4 levels: A single-center, retrospective cohort study

Autoimmune pancreatitis (AIP) is a complex, poorly understood disease gaining increasing attention. "Clinical Characteristics and Outcome of AIP Based on Serum IgG4 levels," investigated AIP with a focus on serum immunoglobulin (Ig) G4 levels. The 213 patients with AIP were classified according to serum IgG4 levels: Abnormal (elevated) and normal. Patients with higher IgG4 levels exhibited a more active immune system and increased relapse rates. Beyond IgG4, the IgA levels and age independently contributed to relapse risk, guiding risk assessment and tailored treatments for better outcomes. However, limitations persist, such as no IgA correlation with IgG4 levels, absent data on autoantibody-positive AIP cases critical for Asian diagnostic criteria, and unexplored relapse rates in high serum IgG AIP by subtype. Genetic factors and family histories were not addressed. As the understanding and referral of seronegative AIPs increase, there's a growing need for commercially available, highly sensitive, and specific autoantibodies to aid in diagnosing individuals with low or absent serum IgG4 levels.

The role of EUS-guided fine needle aspiration in autoimmune pancreatitis: a single center prospective study

OBJECTIVES

Histopathological examination is pivotal in diagnosing autoimmune pancreatitis (AIP). The usefulness of EUS-guided fine needle aspiration (EUS-FNA) in diagnosing AIP remains controversial worldwide. The authors conducted this study to evaluate the efficacy of EUS-FNA for AIP diagnosis using a 22-gauge needle.

METHODS

Between January 2013 and May 2017, 37 patients had imaging studies suggestive of AIP at Tongji Hospital, and 27 patients of them were enrolled in this study. Tissue specimens acquired through EUS-FNA were analyzed for periductal lymphoplasmacytic infiltrate (LPI), storiform fibrosis (SF), obliterative phlebitis (OP) and immunoglobulin G4 (IgG4)-positive plasma cell counts. Clinical Trials.gov no: TJ-C20121220.

RESULTS

LPI and SF were present in 18 (66.67%) and 18 (66.67%) of 27 patients, respectively. Abundant IgG4-positive plasmacyte infiltration >10/high-power field (HPF) was detected in 8 of 27 patients (29.63%). OP and the characteristic findings of idiopathic duct-centric chronic pancreatitis (IDCP) and granulocytic epithelial lesion (GEL) were not detected in this study. According to the International Consensus Diagnostic Criteria (ICDC) for AIP, 5 and 12 of 27 patients were assessed as having level 1 and level 2 histological findings, respectively, suggesting that 17 of 27 patients (62.96%) had lymphoplasmacytic sclerosing pancreatitis (LPSP) based on the ICDC.

CONCLUSIONS

In 92.6% of patients, pancreatic tissues with >5 HPFs were obtained by EUS-FNA using a 22-G needle. In 63% of patients, histology was evaluated to be ≥ level 2 according to the ICDC. The study indicates that EUS-FNA with a 22-G needle is valuable in the histopathological diagnosis of AIP.

Application of international consensus diagnostic criteria to an Italian series of autoimmune pancreatitis

BACKGROUND

International consensus diagnostic criteria (ICDC) have been proposed to classify autoimmune pancreatitis (AIP) in type 1, type 2, or not otherwise specified.

OBJECTIVE

Aim was to apply the ICDC to an Italian series of patients to evaluate the incidence and clinical profiles among different subtypes of AIP.

METHODS

we re-evaluated and classified 92 patients diagnosed by Verona criteria, according to the ICDC.

RESULTS

Out of 92 patients, 59 (64%) were diagnosed as type 1, 17 (18%) as type 2, and 15 (16%) as not otherwise specified according to the ICDC. A significant difference between type 1 and type 2 were found for age (54.5 ± 14.5 vs. 34.4 ± 13.9 respectively; p < 0.0001), male sex (76 vs. 47%; p = 0.007), jaundice (66 vs. 18%; p = 0.002) and acute pancreatitis (9 vs. 47%; p < 0.0001), elevated serum IgG4 levels (85 vs. 7%; p < 0.0001), inflammatory bowel disease (8 vs. 82%; < 0.0001), and relapse of the disease (34 vs. 6%; p = 0.058). Imaging and response to steroids in the not-otherwise-specified group were similar to type 1 and 2.

CONCLUSIONS

Type 1 has a different clinical profile from type 2 autoimmune pancreatitis. The not-otherwise-specified group has peculiar clinical features which are shared both with type 1 or type 2 groups.

International Consensus Diagnostic Criteria for Autoimmune Pancreatitis and Its Japanese Amendment Have Improved Diagnostic Ability over Existing Criteria

Objectives. The recent International Consensus Diagnostic Criteria (ICDC) for autoimmune pancreatitis (AIP) and its Japanese amendment developed by the Japanese Pancreas Society (JPS 2011) may have overcome the drawbacks of earlier criteria and achieved a higher diagnostic ability for AIP. The aim of the present study is to evaluate this possibility and identify the underlying causes of this change. Methods. We compared the diagnostic abilities of the ICDC and JPS 2011 with those of the Japanese diagnostic criteria 2006 (JPS 2006), Korean diagnostic criteria (Korean), Asian diagnostic criteria (Asian), and HISORt diagnostic criteria in 110 patients with AIP and 31 patients with malignant pancreatic cancer. Results. The ICDC achieved the highest diagnostic ability in terms of accuracy (95.0%), followed by JPS 2011 (92.9%), Korean (92.2%), HISORt (88.7%), Asian (87.2%), and JPS 2006 (85.1%). Nearly all criteria systems exhibited a high specificity of 100%, indicating that the enhanced diagnostic ability of the ICDC and JPS 2011 likely stemmed from increased sensitivity brought about by inclusion of diagnostic items requiring no endoscopic retrograde pancreatography. The diagnostic ability of JPS 2011 was nearly equivalent to that of the ICDC. Conclusions. The ICDC and JPS 2011 have improved diagnostic ability as compared with earlier criteria sets because of an increase in sensitivity.

The Spanish Pancreatic Club recommendations for the diagnosis and treatment of chronic pancreatitis: part 1 (diagnosis)

Chronic pancreatitis (CP) is a relatively uncommon, complex and heterogeneous disease. The absence of a gold standard applicable to the initial phases of CP makes its early diagnosis difficult. Some of its complications, particularly chronic pain, can be difficult to manage. There is much variability in the diagnosis and treatment of CP and its complications amongst centers and professionals. The Spanish Pancreatic Club has developed a consensus on the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. A list of questions was drafted, and two experts reviewed each question. Then, a draft was produced and shared with the entire panel of experts and discussed in a face-to-face meeting. This first part of the consensus addresses the diagnosis of CP and its complications.

Clinical differences between mass-forming autoimmune pancreatitis and pancreatic cancer

OBJECTIVE

Autoimmune pancreatitis (AIP) needs to be differentiated from pancreatic cancer (PC). We aimed to clarify the findings specific for AIP by comparing the clinical differences between mass-forming AIP and PC.

MATERIAL AND METHODS

We retrospectively compared 36 patients with mass-forming AIP and 60 with PC without metastasis regarding clinical, imaging, serological, histological differences and other organ involvement (OOI). We evaluated the sensitivity, specificity and accuracy of these findings for the differential diagnosis between AIP and PC.

RESULTS

The findings 100% specific for AIP were a capsule-like rim on computed tomography (CT), skipped lesion of main pancreatic duct (MPD) on endoscopic retrograde pancreatography (ERP) or magnetic resonance cholangiopancreatography (MRCP), γ-globulin > 2 g/dl, OOI (extrapancreatic biliary stricture, salivary gland swelling and retroperitoneal fibrosis) and ruling out PC by histopathological findings of endoscopic ultrasonography-guided fine-needle aspiration. The findings over 90% specific were IgG4 > 280 mg/dl (98%), IgG > 1800 mg/dl (97%), maximal diameter of upstream MPD < 5 mm on MRCP (95%) and IgG4 > 135 mg/dl (94%), respectively.

CONCLUSIONS

Clinical, imaging, serological, histological findings and OOI differed between mass-forming AIP and PC. Capsule-like rim on CT, skipped lesion of MPD on ERP or MRCP, IgG4 > 280 mg/dl, and OOI were highly specific findings for AIP. These findings are useful in the differential diagnosis of mass-forming AIP from PC.

Characteristics of autoimmune pancreatitis based on serum IgG4 level

BACKGROUND

Autoimmune pancreatitis is categorized as an IgG4-related autoimmune disease, mostly associated with serological alterations, however characteristics of autoimmune pancreatitis based on serum markers have not been fully evaluated.

METHODS

We evaluated demographics, symptoms, imaging and therapeutic outcome in 27 cases of autoimmune pancreatitis stratified by serum IgG4 level.

RESULTS

Twenty patients (74%) had elevated serum IgG4 and 7 (26%) had normal IgG4 levels. Compared to patients with normal serum IgG4 levels, patients with elevated IgG4 had higher incidence of jaundice at onset (14.3% vs. 80%, respectively; P=0.002), more frequent diffuse pancreatic enlargement at imaging (14.3% vs. 60%, respectively; P=0.04), significantly higher 18F-2-fluoro-2-deoxy-d-glucose uptake of pancreatic lesions (SUV max: 4.0 vs. 5.7, respectively; P=0.02), more frequent extrapancreatic lesions (42.9% vs. 85%, respectively; P=0.03). Response to steroids was recognized regardless of serum IgG4 level, however maintenance therapy was required more frequently amongst patients with elevated compared to normal IgG4 (85.7% vs. 33.3%, respectively; P=0.04).

CONCLUSIONS

Clinical features of autoimmune pancreatitis are different based on level of serum IgG4. Further studies are needed to clarify if normal serum IgG4 cases are a precursor of active type 1 or type 2 autoimmune pancreatitis.

Autoimmune pancreatitis mimicking pancreatic cancer

BACKGROUND/PURPOSE

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis that can often be difficult to distinguish from pancreatic cancer. We describe the clinical and radiographic features of 23 patients with AIP whose presentations mimicked pancreatic cancer.

METHODS

A review of clinic, radiology, and endoscopy records from a 6-year period identified patients with AIP initially suspected of having pancreatic cancer. Abdominal computed tomography (CT) with intravenous contrast, endoscopic ultrasonography (EUS), and/or ERCP was performed in each patient. The diagnosis of AIP was made histologically and/or cytologically for each patient.

RESULTS

Nineteen of 23 patients (83%) presented with new-onset weight loss, jaundice, or both. Nineteen (83%) patients had CT findings worrisome for pancreatic cancer including: (1) pancreatic enlargement or focal mass, (2) regional lymphadenopathy, and/or (3) vascular invasion. Eighteen patients (78%) had common bile duct strictures on ERCP. EUS-guided fine-needle aspiration biopsies excluded pancreatic cancer in all 22 patients who had EUS (96%). Seven patients had surgery for continued suspicion of pancreatic cancer.

CONCLUSIONS

Although AIP commonly presents with features suggestive of pancreatic cancer, clinical recognition of AIP with appropriate diagnostic testing including EUS with fine-needle aspiration, ERCP, IgG4 levels, and pancreatic protocol CT expedites diagnosis and can spare patients unnecessary surgery.

IgG4-associated cholecystitis: another clue in the diagnosis of autoimmune pancreatitis

PURPOSE

Autoimmune pancreatitis (AIP) is the pancreatic manifestation of IgG4-associated systemic disease (ISD). Criteria for diagnosis of AIP include recognition of extra-pancreatic organ involvement. Because the diagnosis of AIP can be challenging, even for experts, it is important for clinicians to recognize other target organ damage in this disease. Typical gallbladder findings in AIP have been increasingly recognized. Because cholecystectomy is common in the community, the availability of previous tissue from the gallbladder can provide an important supportive clue in the diagnosis of AIP. The objective of this review is to examine the literature on common gallbladder pathology findings in AIP, and discuss their clinical utility.

RESULTS

Gallbladder involvement in AIP seems to be common. Transmural lymphoplasmacytic inflammatory infiltrates, extramural inflammatory nodules, the presence of tissue eosinophilia, phlebitis, and increased tissue IgG4 are all seen more frequently in the gallbladders of patients with AIP. These findings are not 100% specific, because some can be seen in primary sclerosing cholangitis and pancreatic adenocarcinoma.

CONCLUSION

Cholecystectomy for the purpose of diagnosing AIP is not recommended. However, if gallbladder specimens from a previous cholecystectomy are available, an expert review of gallbladder slides with IgG4 immunostaining may help to provide additional criteria for diagnosis of autoimmune pancreatitis.

Endoscopic ultrasonography findings in autoimmune pancreatitis

Endoscopic ultrasonography is an established diagnostic tool for pancreatic masses and chronic pancreatitis. In recent years there has been a growing interest in the worldwide medical community in autoimmune pancreatitis (AIP), a form of chronic pancreatitis caused by an autoimmune process. This paper reviews the current available literature about the endoscopic ultrasonographic findings of AIP and the role of this imaging technique in the management of this protean disease.

IgG₄-related sclerosing disease: a novel mimic of inflammatory bowel disease

High levels of IgG₄-positive plasma cells are commonly seen in autoimmune pancreatitis. It has recently become evident that autoimmune pancreatitis is one component of a larger multi-system disease. IgG₄-positive plasma cells have been identified in many extrapancreatic tissues, including the colon, biliary tract, liver, and lungs, and thus the term "IgG₄-related sclerosing disease" has been proposed. Awareness of IgG₄-related sclerosing disease is important, as it has been shown to mimic other conditions like malignancy. This review discusses IgG₄-related colitis and its potential for mimicking inflammatory bowel disease.

Analysis of humoral immune response in experimental autoimmune pancreatitis in mice

OBJECTIVES

To study the autoimmune response in MRL/Mp mice, which spontaneously develop pancreatitis in the exocrine pancreatic tissue.

METHODS

Six-week-old female mice were injected intraperitoneally with polyinosinic polycytidylic acid at a dose of 5 mg/kg of body weight twice a week for up to 12 weeks. The mice were serially killed, and the severity of their pancreatitis was graded with a histological scoring system. Immunohistological examinations were performed, and the serum levels of autoantibodies were measured by enzyme-linked immunosorbent assay.

RESULTS

The administration of polyinosinic polycytidylic acid accelerated the development of pancreatitis, with abundant infiltration of B220 B cells and CD138 plasmacytes. Various autoantibodies directed against autoantigens, including carbonic anhydrase II and lactoferrin, were detected but none against glutamic acid decarboxylase. Of these, autoantibodies directed against the pancreatic secretory trypsin inhibitor (PSTI; 91.7%) were more prevalent than those against carbonic anhydrase II (33.3%) or lactoferrin (45.8%). Determination of the epitope of the anti-PSTI antibody showed that most immunoreactivity was directed at the site on PSTI that is active in the suppression of trypsin activity.

CONCLUSIONS

The autoimmune response to PSTI protein may induce a failure of PSTI activity, resulting in the activation of trypsinogen and the subsequent disease progression.

Autoimmune pancreatitis: a challenging diagnostic puzzle for clinicians

Autoimmune pancreatitis is a form of pancreatitis with autoimmune stigmata that may present as either focal or diffuse gland involvement. In focal forms, autoimmune pancreatitis shares demographic, clinical, biochemical and imaging features with pancreatic cancer. Since autoimmune pancreatitis is a benign disease and steroid therapy can rapidly resolve symptoms, improve radiological findings and avoid unnecessary surgery, the current clinical challenge is how to differentiate autoimmune pancreatitis from pancreatic neoplasia. Even though definitive diagnosis of the disease is difficult, several diagnostic criteria have been proposed and progress has been made in imaging studies. The management of this unique form of pancreatitis should, therefore, be handled in centres with knowledge of all aspects of the disease. This article briefly reviews clinical aspects of autoimmune pancreatitis with a focus on its diagnostic imaging and management.

Identification of a novel antibody associated with autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is characterized by an inflammatory process that leads to organ dysfunction. The cause of the disease is unknown. Its autoimmune origin has been suggested but never proved, and little is known about the pathogenesis of this condition.

METHODS

To identify pathogenetically relevant autoantigen targets, we screened a random peptide library with pooled IgG obtained from 20 patients with autoimmune pancreatitis. Peptide-specific antibodies were detected in serum specimens obtained from the patients.

RESULTS

Among the detected peptides, peptide AIP(1-7) was recognized by the serum specimens from 18 of 20 patients with autoimmune pancreatitis and by serum specimens from 4 of 40 patients with pancreatic cancer, but not by serum specimens from healthy controls. The peptide showed homology with an amino acid sequence of plasminogen-binding protein (PBP) of Helicobacter pylori and with ubiquitin-protein ligase E3 component n-recognin 2 (UBR2), an enzyme highly expressed in acinar cells of the pancreas. Antibodies against the PBP peptide were detected in 19 of 20 patients with autoimmune pancreatitis (95%) and in 4 of 40 patients with pancreatic cancer (10%). Such reactivity was not detected in patients with alcohol-induced chronic pancreatitis or intraductal papillary mucinous neoplasm. The results were validated in another series of patients with autoimmune pancreatitis or pancreatic cancer: 14 of 15 patients with autoimmune pancreatitis (93%) and 1 of 70 patients with pancreatic cancer (1%) had a positive test for anti-PBP peptide antibodies. When the training and validation groups were combined, the test was positive in 33 of 35 patients with autoimmune pancreatitis (94%) and in 5 of 110 patients with pancreatic cancer (5%).

CONCLUSIONS

The antibody that we identified was detected in most patients with autoimmune pancreatitis but also in some patients with pancreatic cancer, making it an imperfect test to distinguish between these two conditions.

A case of IgG4-related sclerosing disease with retroperitoneal fibrosis, autoimmune pancreatitis and bilateral focal nephritis

A 74-year-old male patient presented with progressive anorexia, cholestatic liver function tests, and a diffuse enlarged pancreas suggestive of a pancreatic carcinoma. There was a marked elevation of total immunoglobulin G4 (IgG4) in serum. Further investigation led to the diagnosis of IgG4-related sclerosing disease with involvement of the pancreas, retroperitoneal fibrosis, and bilateral focal nephritis. To our knowledge, this is the first report on these 3 clinical entities occurring in the same patient.A short review of the literature concerning autoimmune pancreatitis and retroperitoneal fibrosis is made, with special interest to the concept of IgG4-related pathology. This systemic disease can have several clinical manifestations: IgG4-positivity not only can be found in the pancreas, but also at the level of extrahepatic biliary ducts, gallbladder, salivary glands, retroperitoneal tissue, kidneys, ureters, and lymph nodes. Although further investigation is required to determine its exact pathophysiologic role, IgG4 seems to be an important key player.

Is (18)F-fluorodeoxyglucose positron emission tomography meaningful for estimating the efficacy of corticosteroid therapy in patients with autoimmune pancreatitis?

BACKGROUND

Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic cancer (PC). Both conditions accumulate (18)F-fluorodeoxyglucose (FDG), so FDG positron emission tomography (FDG-PET) is not discriminatory. This study aimed to evaluate the pattern of FDG accumulation, and the change in FDG uptake after steroid treatment in AIP and PC.

METHODS

We compared FDG-PET patterns between 18 patients with AIP and 20 patients with PC, and also evaluated the short-term changes in FDG uptake after steroid therapy.

RESULTS

FDG uptake was observed in 88.9% in AIP and 90.0% in PC. FDG uptake in extra-abdominal lymph nodes was seen more frequently in AIP, and uptake in salivary glands, eyes and biliary ducts was seen only in AIP. Follow-up PET was performed in 6 AIP patients and in 3 PC patients. Changes in SUV(max) after steroid therapy were estimated within 1 week in 5 AIP patients and in all 3 PC patients, retrospectively. In 4 AIP patients, the change in SUV(max) was more than 10%. On the other hand, in PC, SUV(max) increased or remained almost unchanged (within 10%).

CONCLUSIONS

FDG-PET pattern at baseline, and a decrease in FDG uptake after a short steroid trial can be useful for discriminating AIP from PC.

Histological diagnosis of autoimmune pancreatitis using EUS-guided trucut biopsy: a comparison study with EUS-FNA

PURPOSE

The aim of this study was to evaluate the feasibility and safety of endoscopic ultrasonography (EUS)-guided trucut biopsy (TCB) for diagnosis of autoimmune pancreatitis (AIP).

METHODS

Fourteen patients with suspected AIP based on imaging studies underwent both EUS-guided fine-needle aspiration (FNA) and EUS-TCB for diagnosis of AIP and exclusion of pancreatic cancer (PC). According to the revised Japanese clinical diagnostic criteria, AIP was diagnosed in eight while the remaining six patients had pancreatitis of other etiologies. Pathologically, AIP was defined as lymphoplasmacytic sclerosing pancreatitis (LPSP), and sub-divided into two types: definite LPSP (d-LPSP) showing fulspectrum of LPSP and probable LPSP (p-LPSP) without obliterative phlebitis or abundant (>10 cells/hpf) IgG4-positive plasmacytes infiltration.

RESULTS

PC was excluded in all patients. EUS-FNA resulted in three of eight patients with AIP were reported as p-LPSP, one was reported as normal, and 4 were inconclusive. One of six with non-autoimmune pancreatitis was diagnosed as p-LPSP on EUS-FNA, one as idiopathic chronic pancreatitis (ICP) and four were inconclusive. By using EUS-TCB, all AIP patients were diagnosed as LPSP (4 d-LPSP and 4 p-LPSP). Of the six patients with non-autoimmune pancreatitis, three were diagnosed as LPSP (1 d-LPSP and 2 p-LPSP) and three showed ICP on TCB. No complications were identified in any patient with either EUS-FNA or TCB.

CONCLUSION

EUS-TCB is a safe and accurate procedure for obtaining a histological diagnosis in patients with suspected AIP. EUS-TCB can serve as a rescue technique in cases of AIP lacking typical findings.

[Autoimmune pancreatitis]

Autoimmune pancreatitis has been established as a special entity of pancreatitis. It is an enigmatic disease since it is adding an autoimmune etiology to the existing causes of pancreatitis. Morphological hallmarks of the disease are narrowing of the pancreatic duct system and the bile duct by periductal lymphoplasmocytic inflammation. This results in many cases in obstructive jaundice due to a mass-forming lesion in the pancreatic head mimicking pancreatic ductal adenocarcinoma. Therefore, patients will frequently undergo surgery. Histopathologically, the disease can be diagnosed by IgG4-positive plasma cells. Serologically, patients may present with elevated serum IgG and IgG4 levels. Other autoantibodies are also described. Association with other autoimmune manifestations in a wide range of organs is frequent. Autoimmune pancreatitis will respond to steroid treatment, which is of specific importance because pancreatic cancer is one of its clinical differential diagnoses. It is important to positively diagnose autoimmune pancreatitis, especially if the bile ducts are affected, since cholangitis may be or become a prominent problem before or after surgery.

The clinical and radiological characteristics of focal mass-forming autoimmune pancreatitis: comparison with chronic pancreatitis and pancreatic cancer

OBJECTIVES

We investigated the clinical and radiological features of focal mass-forming autoimmune pancreatitis (FMF AIP) to help physicians avoid performing unnecessary surgery because of an improper diagnosis.

METHODS

We evaluated 23 patients with chronic inflammatory pancreatic masses and who underwent pancreatectomy for presumed pancreatic cancer from April 1995 to December 2005. These patients were distinguished into 8 FMF AIP patients and 15 ordinary chronic pancreatitis patients through a histological review, along with considering the immunoglobulin G4 staining. Twenty-six randomly selected pancreatic cancer patients were also evaluated as a control group.

RESULTS

On the portal venous phase of computed tomography, 6 (85.7%) of 7 FMF AIP patients showed homogeneous enhancement, whereas only 3 chronic pancreatitis patients (25%) and none of the pancreatic cancer patients showed homogeneous enhancement (P < 0.001). None of the FMF AIP patients showed upstream main pancreatic duct dilatation greater than 5 mm or proximal pancreatic atrophy.

CONCLUSIONS

For patients with a pancreatic mass, if their radiological images show homogeneous enhancement on the portal venous phase, the absence of significant upstream main pancreatic duct dilatation greater than 5 mm, and the absence of proximal pancreatic atrophy, then conducting further evaluations should be considered to avoid performing unnecessary surgery.

Chronic pancreatitis: report from a multicenter Italian survey (PanCroInfAISP) on 893 patients

BACKGROUND

No data on chronic pancreatitis in Italy are available yet.

AIM

To evaluate demographic, clinical, diagnostic and therapeutic aspects in patients suffering from chronic pancreatitis.

PATIENTS AND METHODS

Eligible patients were prospectively enrolled from 2000 to 2005. Information concerning demographic data, lifestyle risk factors, family and clinical history, associated factors (alcohol, autoimmunity, cystic dystrophy of the duodenal wall, obstruction, genetic mutations) concomitant diseases, diagnostic findings, and pharmacological, endoscopic and surgical therapy were gathered.

RESULTS

893 patients (74% males, mean age 53.7+/-15.2 years) were evaluated. 519/859 patients (60%) were drinkers and 555/840 (66%) were smokers. A strong positive correlation between drinking and cigarette consumption (R=0.53; p<0.0001) was found. Heavy alcohol consumption (>80g of alcohol/day for more than 5 years) was considered the most important risk factor in 300 patients (34%), obstruction in 238 (27%), alcohol and obstruction in 82 (9%), autoimmunity in 34 (4%), cystic dystrophy of the duodenal wall/groove pancreatitis in 55 (6%), gene mutations in 36 (4%), and none (idiopathic) in 148 (17%). Bile stones were diagnosed in 287 patients (33%) and cholecystectomy was performed in 329 patients (38%). Pancreatic calcifications were diagnosed in 547/879 patients (62%). Pancreatic surgery was performed in 273 patients (31%). Endoscopic sphincterotomy was performed in 371 patients (42%). Exocrine and endocrine insufficiency were found, respectively, in 373/834 (45%) and 275/885 patients (31%).

CONCLUSIONS

An unexpected low frequency of alcohol abuse and new emerging associated risk factors for chronic pancreatitis were observed in Italy.

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.

Early rise in inflammation and microcirculatory disorder determine the development of autoimmune pancreatitis in the MRL/Mp-mouse

Autoimmune pancreatitis (AIP) is a rare cause of chronic pancreatitis and mimics pancreatic cancer. Although there is strong interest in research, etiology and pathophysiology of AIP are still unknown. Therefore, we analyzed a total of 92 MRL/Mp-mice of either sex, which are prone to develop AIP, in four different age groups (8-12, 16-20, 24-28, and 32-40 wk). Using intravital fluorescence microscopy, histology, laboratory analysis, and Western blot, onset, severity, and pathophysiological mechanisms of AIP were evaluated. Female animals showed in vivo an age-dependent increase of intrapancreatic leukocyte accumulation, as well as a loss in functional capillary perfusion. In contrast, intrapancreatic inflammation in male mice was less pronounced and not age dependent. Furthermore, pancreatic tissue specimen of female animals exhibited major organ destruction with significantly higher values of mean pathological scores (1.5 +/- 0.3 vs. < or =0.2; P < 0.05), as well as significantly increased CD4-, CD8-, CD11b-, and CD138-positive cells compared with male animals of the same age. Interestingly, there was a significant positive correlation between intravascular leukocyte adherence and the histopathological score of the pancreas, indicating a determining role of the innate immune system for the late onset of AIP. The present study shows that the onset of AIP is characterized by an inflammatory response and microcirculatory failure, most probably constituting initiators and propagators of this autoimmune disease.

[Bile duct involvement in autoimmune pancreatitis: classification and treatment]

Autoimmune pancreatitis is a rare disease characterized by inflammation of the pancreatic parenchyma, irregular narrowing of the pancreatic duct, periductal lymphoplasmacytic infiltration and fibrosis at histological examination, the presence of autoantibodies and hypergammaglobulinemia, as well as the possible association of cholangitis and other autoimmune diseases. There is a favorable response to steroid therapy. We report the case of a patient with autoimmune pancreatitis with bile duct involvement and peripheral eosinophilia, requiring long-term immunosuppressant treatment. The diagnosis of a diffuse form of AIP was made without direct histological evidence and based on indirect imaging, clinical and laboratory findings in an autoimmune context. The histological and imaging studies of bile duct involvement and the favourable response to steroids were additional arguments.

New insights into autoimmune liver diseases

Autoinflammatory liver disease represents an important aspect of global hepatological practice. The three principal disease divisions recognized are autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis. Largely, but not exclusively, these diseases are considered to be autoimmune in origin. Increased recognition of outlier and overlap syndromes, changes in presentation and natural history, as well as the increased awareness of IgG4-associated sclerosing cholangitis, all highlight the limitations of the classic terminology. New insights continue to improve the care given to patients, and have arisen from carefully conducted clinical studies, therapeutic trials, as well as genetic and laboratory investigations. The challenges remain to treat patients before liver injury becomes permanent and to prevent the development of organ failure.

Isolated Lymphoplasmacytic Sclerosing Pancreatitis Involving the Pancreatic Tail

We present an interesting case of a 62-year-old woman with a 3-month history of vague, left-sided abdominal pain. CT imaging revealed a hypodense lesion in the tail of the pancreas. The patient had no history of pancreatitis or autoimmune diseases. Laboratory testing revealed a normal CA19-9 (33 U/mL) and an elevated IgG4 (133 mg/dL). Due to concerns of pancreatic malignancy, she underwent operation. We found a dense, inflammatory mass in the tail of the pancreas, which was removed via an open distal pancreatectomy with splenectomy. Histologic analysis revealed a pancreas with sclerotic ducts and surrounding lymphoplasmacytic inflammation most consistent with lymphoplasmacytic sclerosing pancreatitis (LPSP). LPSP, also termed autoimmune pancreatitis, is a benign disease of the pancreas, which can mimic pancreatic adenocarcinoma. It is the most common benign finding diagnosed on pathology after pancreatic resection for presumed malignancy. LPSP most commonly involves the head and, more uncommonly, the tail of the pancreas. It can be successfully treated with steroids obviating the need for resection. IgG4 levels may assist in recognition of this disease. As our experience with utilization of IgG4 testing and knowledge of the systemic nature of LPSP increase, patients with this disease may be spared unnecessary resection.

[Autoimmune pancreatitis]

Autoimmune pancreatitis is a rare form of chronic pancreatitis. Its clinical relevance, however, cannot be dismissed, as it can be difficult to distinguish autoimmune pancreatitis from malignant pancreatic cancer and in contrast with the majority of chronic pancreatitis forms it can be efficiently treated, even complete remission can be achieved on steroid therapy. The clinical picture of autoimmune pancreatitis is not characteristic, obstructive jaundice, abdominal pain, weight loss are frequently observed. Imaging studies often show diffuse pancreas enlargement and irregular narrowing of the main pancreatic duct. Elevated serum IgG4 immunoglobulin concentrations, some autoantibodies and the presence of IgG4 positive immune cells were observed in addition to other histological features. Apart from pancreatic manifestations, other organs may also be affected, thus associations with sclerosing cholangitis, sialoadenitis, retroperitoneal fibrosis, Riedel thyroiditis and inflammatory bowel diseases have been described. Based on these findings, autoimmune pancreatitis should be regarded as a systemic disease, as a manifestation of systemic IgG4-related sclerosing disease.

Substitution of aspartic acid at position 57 of the DQbeta1 affects relapse of autoimmune pancreatitis

BACKGROUND & AIMS

Although autoimmune pancreatitis (AIP) responds well to corticosteroid therapy, relapse during maintenance corticosteroid therapy or after the withdrawal of corticosteroid treatment is not uncommon. To date, the factors related to relapse of AIP have not been fully explored.

METHODS

To determine the clinical and genetic predictors relating to the relapse of AIP, we evaluated clinical factors, HLA polymorphisms, and the amino acid sequences in 40 patients with AIP.

RESULTS

At a median follow-up period of 40 months (range, 12-67 months), relapse developed in 13 of 40 patients with AIP (33%), in whom complete remission was achieved with oral corticosteroid therapy. Among demographics, clinical characteristics in the initial diagnosis of AIP, we could not find any clinical predictor for relapse of AIP; however, in amino acid sequence analysis for relapse of AIP, the substitution of aspartic acid to nonaspartic acid at residue 57 of DQbeta1 showed a significant association with relapse of AIP (nonrelapse group, 29.6%; relapse group, 100%; P = .00003; odds ratio, 3.38; 95% confidence interval, 1.9-6.0). There was a significant difference in the timing of relapse of AIP, according to density of the nonaspartic acid residue at DQbeta1 57 (nonaspartic acid homozygosity: mean +/- SD, 6.7 +/- 4.2 months; nonaspartic acid heterozygosity: mean +/- SD, 33 +/- 11 months; P < .001).

CONCLUSIONS

Substitution of aspartic acid to nonaspartic acid at DQbeta1 57 appears to represent a key genetic factor for relapse of AIP (ClinicalTrials.gov number, NCT00444444).

Serum Immunoglobulin G Fraction 4 Levels in Pancreatic Cancer: Elevations Not Associated With Autoimmune Pancreatitis

Context.—Autoimmune pancreatitis is an uncommon, inflammatory disease of the pancreas that presents with clinical features, such as painless jaundice and a pancreatic mass, similar to those caused by pancreatic cancer. Patients with autoimmune pancreatitis frequently have elevated serum immunoglobulin G fraction 4 (IgG4) levels, and their pancreatic tissue may show IgG4-positive plasma cell infiltration. It is imperative to differentiate autoimmune pancreatitis from pancreatic cancer because autoimmune pancreatitis typically responds to corticosteroid treatment. A previous Japanese study reported that serum IgG4 greater than 135 mg/dL was 97% specific and 95% sensitive in predicting autoimmune pancreatitis.

Objective.—To prospectively measure serum IgG4 levels in pancreatic cancer patients to ascertain whether increased levels might be present in this North American population.

Design.—We collected blood samples and phenotypic information on 71 consecutive pancreatic cancer patients and 103 healthy controls who visited our clinics between October 2004 and April 2006. IgG4 levels were determined using a single radial immunodiffusion assay. A serum IgG4 level greater than 135 mg/dL was considered elevated.

Results.—Five cancer patients had IgG4 elevation, with a mean serum IgG4 level of 160.8 mg/dL. None of our cancer patients with plasma IgG4 elevation demonstrated evidence of autoimmune pancreatitis. One control subject demonstrated elevated serum IgG4 unrelated to identified etiology.

Conclusions.—As many as 7% of patients with pancreatic cancer have serum IgG4 levels above 135 mg/dL. In patients with pancreatic mass lesions and suspicion of cancer, an IgG4 level measuring between 135 and 200 mg/dL should be interpreted cautiously and not accepted as diagnostic of autoimmune pancreatitis without further evaluation.

Autoimmune chronic pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis that is characterized by swelling of the pancreas, narrowing of the main pancreatic duct (MPD), elevation of serum gamma globulin, or immunoglobulin G or presence of autoantibody, lymphoplasmacytic infiltration and dense fibrosis on histopathology. It is responsive to steroid therapy. The incidence of AIP can reach 5-6% of chronic pancreatitis. It can present as obstructive jaundice, body weight loss, and pancreas head mass mimicking pancreatic cancer. The recognition of AIP can avoid major surgery such as pancreatic resection.

METHODS

From May 2003 to July 2007, a total of 5 cases of AIP were reviewed retrospectively. The diagnosis was made on imaging study, serology, steroid response and/or histology if surgery was carried out.

RESULTS

There were 2 male and 3 female patients, with a mean age of 61 (39-75) years. Atypical AIP was found in the first case and typical AIP in the remaining 4. The presenting clinical pictures were mild epigastric pain, obstructive jaundice, and loss of body weight in 4 cases, with associated autoimmune disease in 1. Diffuse or long segmental enlargement of the pancreas without peripancreatic fat infiltration was found in all patients except 1 who only had focal pancreatic head enlargement. Distal common bile duct (CBD) stricture was seen in 4 cases and the median CBD stricture length was 1.2 (0.5-2.5) cm. Multiple narrowing of the whole MPD was seen in 2 cases, focal narrowing of the MPD in 2 and long segmental narrowing of the MPD in 1. Serum immunoglobulin G tests were done in 4 cases and were elevated in all. Antinuclear antibody was positive in 3. The first case was operated on after a preoperative diagnosis of suspicious pancreatic head tumor. The subsequent 3 cases were diagnosed correctly as AIP. The last case presented with distal CBD stricture and hypoechoic lesion in the pancreas head on endoscopic ultrasound, with only borderline pancreatic enlargement on computed tomography, and he was operated on. Retrospective endoscopic retrograde pancreatogram review revealed MPD narrowing in the pancreatic body. Endoscopic retrograde brush cytology was performed and was negative for malignancy in 3 cases. Steroid therapy was given in 3 and was responsive, but there were 2 recurrences.

CONCLUSION

AIP should be a differential diagnosis in distal CBD stricture and pancreatic head mass when the patient has: (1) diffuse or long segmental enlargement of the pancreas without peripancreatic fat infiltration, with multiple narrowing of the MPD without much upstream dilatation, or narrowing of the MPD not corresponding to the region of CBD stricture; and (2) abnormal immunoserologic tests.