Autoimmune pancreatitis and IgG4-related sclerosing cholangitis. Curr Opin Rheumatol. 2011;23:80-87. [PMID: 21124090 DOI: 10.1097/BOR.0b013e3283412f60]

[Immunoglobulin G (IgG) 4-related diseases]

Immunoglobulin G (IgG) 4‑related diseases are fibrosing inflammatory systemic diseases that can affect almost every organ system. Typical disease manifestations include autoimmune pancreatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory orbitopathy and involvement of the salivary and lacrimal glands. Organ involvements can occur either isolated or in combination with other disease manifestations. Before diagnosing IgG4-related diseases, malignancies and other inflammatory diseases have to be excluded. The diagnosis requires a combination of laboratory findings, histological and radiological results. Typically, IgG4-related diseases respond well to glucocorticosteroids. In cases of relapse or severe organ involvement a longer term immunosuppression is often required, whereas watch and wait can also be sufficient in milder cases.

Isolated mass-forming IgG4-related sclerosing cholangitis masquerading as extrahepatic cholangiocarcinoma: A case report

BACKGROUND

IgG4-related sclerosing cholangitis (IgG4-RSC) is an uncommon benign disease, and its rarer, isolated and mass-forming subtype poses a significant challenge to differential diagnosis from cholangiocarcinoma of the extrahepatic bile duct. We herein report a case of isolated IgG4-RSC with an obstructing bile duct mass, for which extrahepatic bile duct resection was performed under the impression of proximal common bile duct (CBD) cancer.

CASE SUMMARY

A 79-year-old male was admitted for jaundice that had developed 1 mo prior. There was no family history for autoimmune diseases or biliary cancer. Computed tomography (CT) and magnetic resonance cholangiopancreaticography revealed a short segmental concentric wall thickening of the proximal CBD with diffuse dilatation of the bile duct to the periphery. The endoscopic biopsy specimen showed no malignant cells. Positron emission tomography-CT showed a focal hypermetabolic lesion (SUVmax 4.2) in and around the proximal CBD area. With the impression of proximal CBD cancer, we performed segmental resection of the extrahepatic bile duct. Histopathology demonstrated marked sclerosis with diffuse lymphoplasmacytic infiltration and some eosinophils. Immunohistochemical staining for IgG4 showed increased positivity in some areas (up to 30/high-power field) and IgG4+/IgG+ cell ratio as 30%-50%. Pathologists’ impression was IgG4-related sclerosing disease. Follow-up serum IgG4 levels were continuously elevated; however, no evidence of relapse or other organ involvement related to IgG4-RSC presented.

CONCLUSION

Isolated and mass-forming IgG4-RSC displays striking similarity with cholangiocarcinoma. To avoid unnecessary major surgery, high index of suspicion is needed.

Antibodies and Immunity During Kawasaki Disease

The cause of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology studies support that an infectious disease is involved in at least starting the inflammatory cascade set off during KD. Clues from epidemiology support that humoral immunity can have a protective effect. However, the role of the immune system, particularly of B cells and antibodies, in pathogenesis of KD is still unclear. Intravenous immunoglobulin (IVIG) and other therapies targeted at modulating inflammation can prevent development of coronary aneurysms. A number of autoantibody responses have been reported in children with KD and antibodies have been generated from aneurysmal plasma cell infiltrates. Recent reports show that children with KD have similar plasmablast responses as other children with infectious diseases, further supporting an infectious starting point. As ongoing studies are attempting to identify the etiology of KD through study of antibody responses, we sought to review the role of humoral immunity in KD pathogenesis, treatment, and recovery.

B Cells and Antibodies in Kawasaki Disease

The etiology of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology supports a relationship of KD to an infectious disease. Several pathological mechanisms are being considered, including a superantigen response, direct invasion by an infectious etiology or an autoimmune phenomenon. Treating affected patients with intravenous immunoglobulin is effective at reducing the rates of coronary aneurysms. However, the role of B cells and antibodies in KD pathogenesis remains unclear. Murine models are not clear on the role for B cells and antibodies in pathogenesis. Studies on rare aneurysm specimens reveal plasma cell infiltrates. Antibodies generated from these aneurysmal plasma cell infiltrates showed cross-reaction to intracellular inclusions in the bronchial epithelium of a number of pathologic specimens from children with KD. These antibodies have not defined an etiology. Notably, a number of autoantibody responses have been reported in children with KD. Recent studies show acute B cell responses are similar in children with KD compared to children with infections, lending further support of an infectious disease cause of KD. Here, we will review and discuss the inconsistencies in the literature in relation to B cell responses, specific antibodies, and a potential role for humoral immunity in KD pathogenesis or diagnosis.

Biliary Involvement in Type 2 Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is a rare condition classified in 2 subtypes. Their distinction relies on a combination of clinical, serological, morphological and histological features. Type 1 is a pancreatic manifestation of IgG4-related disease characterized by multiorgan infiltration by IgG4 plasmocytes. In this condition, hepatobiliary infiltration is frequent and often mimics cholangiocarcinoma or primary sclerosing cholangitis. On the other hand, type 2 is commonly limited to the pancreas. Herein, we describe the case of a patient who presented a type 2 AIP associated with cholangiopathy, a condition not described in the established criteria. He first developed a pancreatitis identified as type 2 by the typical histopathological features and lack of IgG4 in the serum and tissue. Despite a good clinical response to steroids, cholestasis persisted, identified by MR cholangiography as a stricture of the left hepatic duct with dilatation of the intrahepatic bile duct in segments 2 and 3. Biliary cytology was negative. Evolution was favorable but after steroid tapering a few months later, the patient suffered from recurrence of the pancreatitis as well as progression of biliary attempt, suspicious for cholangiocarcinoma. As the investigations again ruled out neoplastic infiltration or primary sclerosing cholangitis, azathioprine was initiated with resolution of both pancreatic and biliary attempts.

Suppressed plasmablast responses in febrile infants, including children with Kawasaki disease

Background

Kawasaki disease (KD), the leading cause of acquired heart disease in children, primarily affects infants and toddlers. Investigations on immune responses during KD are hampered by a limited understanding of normal immune responses in these ages. It’s well known that Infants have poorer vaccine responses and difficulty with maintaining prolonged serum immunity, but there are few studies on human infants detailing immune deficiencies. Limited studies propose an inability to maintain life-long bone marrow plasma cells. Plasmablasts are a transitional cell form of B cells that lead to long-term Plasma cells. Plasmablasts levels rise in the peripheral blood after exposure to a foreign antigen. In adult studies, these responses are both temporally and functionally well characterized. To date, there have been few studies on plasmablasts in the predominant age range of KD.

Methods

Children presenting to an urban pediatric emergency room undergoing laboratory evaluation, who had concern of KD or had fever and symptoms overlapping those of KD, were recruited. Peripheral blood mononuclear cells were isolated and evaluated utilizing flow cytometry with specific B cell markers from 18 KD subjects and 69 febrile controls.

Results

Plasmablast numbers and temporal formation are similar between infectious disease controls and KD subjects. In both groups, infants have diminished plasmablast responses compared to older children.

Conclusion

In this single-time point survey, infants have a blunted peripheral plasmablast response. Overall, similar plasmablast responses in KD and controls support an infectious disease relationship to KD. Future time-course studies of plasmablasts in infants are warranted as this phenomenon may contribute to observed immune responses in this age group.

Current approach to the diagnosis of IgG4-related disease - Combination of comprehensive diagnostic and organ-specific criteria

IgG4-related disease (IgG4-RD) is a fascinating clinical entity proposed by Japanese investigators, and includes a wide variety of diseases, formerly diagnosed as Mikulicz's disease (MD), autoimmune pancreatitis (AIP), interstitial nephritis, prostatitis, retroperitoneal fibrosis, etc. Although all clinicians in every field of medicine may encounter this new disease, a unifying diagnostic criterion has not been established. In 2011, the Japanese IgG4 team, organized by the Ministry of Health, Labor and Welfare (MHLW) of Japan, published comprehensive diagnostic criteria for IgG4-RD. Several problems with these criteria have arisen in clinical practice, however, including the difficulty obtaining biopsy samples from some patients, and the sensitivity and the specificity of techniques used to measure serum IgG4 concentrations. Although serum IgG4 concentration is an important clinical marker for IgG4-RD, its diagnostic utility in differentiating IgG4-RD from other diseases, called IgG4-RD mimickers, remains unclear. This review describes the current optimal approach for the diagnosis of IgG4-RD, based on both comprehensive and organ-specific diagnostic criteria, in patients with diseases such as IgG4-related pancreatitis (AIP), sclerosing cholangitis, and renal, lung and orbital diseases.

Advances in research of immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4 (IgG4)-related sclerosing cholangitis is a special form of cholangitis. As an autoimmune disease, IgG4-related sclerosing cholangitis has no specific clinical manifestations, and its pathogenesis remains unclear. In patients with this disease, serum concentration of IgG4 is elevated, intrahepatic or extrahepatic bile duct stenosis associated with biliary wall thickening is often revealed by biliary imaging, autoimmune diseases such as autoimmune pancreatitis may be present, and massive IgG4 positive plasma cell infiltration and widespread bile duct wall fibrosis are often showed by histopathological examination. It is often difficult to differentiate IgG4-related sclerosing cholangitis from primary sclerosing cholangitis, secondary sclerosing cholangitis and bile duct cancer. However, the disease is sensitive to hormone therapy. This article will review the current advances in research of IgG4-related sclerosing cholangitis.

Sequential Evaluation of Pancreato-Biliary Findings in a Case with IgG4-Associated Cholangiopathy and Autoimmune Pancreatitis during Corticosteroid Treatment

BACKGROUND

Immunoglobulin G4 (IgG4)-associated diseases mostly involve the pancreaticobiliary tree and pancreatic parenchyma. This disease complex is characterized by marked response to corticosteroid therapy and response to steroids is incorporated in the diagnostic algorithm of IgG4 associated diseases. However, there is much unknown about the sequences and duration of healing during the corticosteroid therapy in the literature.

CASE REPORT

In this case report, we report a young male patient with IgG4 associated extrahepatic biliary stricture and autoimmune pancreatitis successfully treated with corticosteroids. Recovery in the laboratory and radiological findings seemed to correlate well with the decrease in serum IgG4 levels in this patient. We also discussed sequences and the duration of healing in the pancreaticobiliary tree and pancreatic parenchymal manifestations in this case report.

CONCLUSION

There is a gap in our knowledge about the evaluation of response criteria after steroid trial with regard to the duration and sequences of healing in the pancreaticobiliary involvement in diagnosing IgG4-related biliary and pancreatic diseases.

Comparison of the multidetector-row computed tomography findings of IgG4-related sclerosing cholangitis and extrahepatic cholangiocarcinoma

AIM

To compare the multidetector-row computed tomography (MDCT) findings of IgG4-related sclerosing cholangitis (IgG4-SC) and extrahepatic cholangiocarcinoma (EH-CCA).

MATERIALS AND METHODS

Two radiologists who had no knowledge of the patients' clinical information retrospectively evaluated the CT findings of patients with IgG4-SC (n=33) and EH-CCA (n=39) on a consensus basis. Another radiologist measured the biliary lesions. IgG4-SC was diagnosed using the Japan Biliary Association criteria (2012) or the Mayo Clinic's HISORt criteria. EH-CCA was diagnosed based on surgical findings.

RESULTS

Compared with EH-CCA, IgG4-SC exhibited the following findings significantly more frequently: (a) wall thickening alone, (b) concentric wall thickening, (c) smooth inner margins, (d) homogeneous attenuation in the arterial phase, (e) a lesion involving the intrapancreatic bile duct, (f) smooth outer margins, (g) fully visible lumen, (h) a funnel-shaped proximal bile duct, (i) skip lesions, and (j) abnormal pancreatic findings. Conversely, (k) dual-layered attenuation in all phases was significantly more common in EH-CCA. The specificity values of parameters (e-k) were >80%. Regarding dimensions, (l) the biliary lesions were longer in IgG4-SC than in EH-CCA. (m) The diameters of the dilated proximal common bile duct and (n) the dilated proximal intrahepatic bile duct were smaller in IgG4-SC than in EH-CCA.

CONCLUSION

A number of CT findings are useful for differentiating between IgG4-SC and EH-CCA. CT findings (e-k) are particularly useful for this purpose.

The importance of IgG4 in the predictive model of thyroiditis

Immunoglobulin (Ig)G4-related sclerosing disease (IgG4-RSD) is a new disease entity first proposed with regard to autoimmune pancreatitis. A 67-year-old male patient was examined because of weight loss and an abdominal pain. Based on the clinical characteristics, laboratory parameters and ultrasound features, we identified the diagnosis of the IgG4-related systemic disease (IgG4-RSD), that was confirmed by the histopathological analysis after the biopsy of the head of pancreas. After confirmation, we started with the corticosteroid therapy with a good clinical, biochemical and morphological response. During the previous therapy, the disturbance of glucoregulation appeared, so we had to change the modality of treatment. We decided to add Azathioprine to the therapy in a dose of 150 mg/day. We achieved a stable phase of the disease with IgG 4.37 g/l and IgG4 0.179 g/l, and with no side effects from the therapy.

The changing faces of IgG4-related disease: Clinical manifestations and pathogenesis

Since the earliest reports in 2001, immunoglobulin G4 (IgG4)-related disease has been defined as an autoimmune systemic disease characterized by the lymphoplasmacytic infiltration of affected tissues leading to fibrosis and obliterative phlebitis along with elevated serum IgG4 levels. Prior to this unifying hypothesis, a plethora of clinical manifestations were considered as separate entities despite the similar laboratory profile. The pathology can be observed in virtually all organs and may thus be a challenging diagnosis, especially when the adequate clinical suspicion is not present or when obtaining a tissue biopsy is not feasible. Nonetheless, the most frequently involved organs are the pancreas and exocrine glands but these may be spared. Immunosuppressants lead to a prompt clinical response in virtually all cases and prevent histological sequelae and, as a consequence, an early differential diagnosis from other conditions, particularly infections and cancer, as well as an early treatment should be pursued. We describe herein two cases in which atypical disease manifestations were observed, i.e., one with recurrent neck lymph node enlargement and proptosis, and one with jaundice. Our understanding of the pathogenesis of IgG4-related disease is largely incomplete but data support a significant role for Th2 cytokines with the contribution of innate immunity factors such as Toll-like receptors, macrophages and basophils. Further, macrophages activated by IL4 overexpress B cell activating factors and contribute to chronic inflammation and the development of fibrosis. We cannot rule out the possibility that the largely variable disease phenotypes reflect different pathogenetic mechanisms and the tissue microenvironment may then contribute to the organ involvement.

[Chronic bilateral orbital tumors in IgG4-related disease]

BACKGROUND

The IgG4-related disease describes a new multisystem disorder, which can also be manifested in the orbit. This syndrome is characterized by a multifocal chronic fibroinflammation with high levels of plasma cells expressing IgG4.

CASE REPORT

This article reports the case of a patient with advanced bilateral tumors of the upper eyelid and orbit. The diagnosis of IgG4-related disease was only revealed after many years and after many biopsies of the tumors had been carried out. The initiation of a systemic steroid therapy led to a rapid reduction of the tumors and an improvement in the general condition of the patient.

Intracranial Inflammatory Pseudotumors Associated with Immunoglobulin G4-Related Disease Mimicking Multiple Meningiomas: A Case Report and Review of the Literature

BACKGROUND

Immunoglobulin G (IgG)4-related disease is a syndrome that forms inflammatory pseudotumors with increasing IgG4-positive plasma cells and lymphocytes infiltrating the exocrine gland and other organs. The concept of this disease gradually has gained more recognition. However, reports of intracranial pseudotumors associated with IgG4-related disease are very rare. The purpose of this report is to provide further information helpful in distinguishing IgG4-related disease from multiple meningiomas.

CASE DESCRIPTION

We report a case of a 62-year-old man who presented with visual disturbance and quadrantanopia of the right eye. Magnetic resonance imaging revealed uniformly enhancing masses located near the right paraclinoid at the right Meckel's cave and along the left foramen magnum. He had experienced autoimmune pancreatitis 7 years previously, and the condition had responded to steroid therapy. Laboratory data revealed elevation of IgG (1877 mg/dL) and IgG4 (405 ng/dL). The right paraclinoidal lesion causing visual disturbance was subtotally removed, which provided sufficient decompression of the right optic nerve. IgG4 was strongly positive on immunohistochemical staining, and we started oral corticosteroid medication. Consequently, all lesion masses shrank remarkably within 1 month.

CONCLUSION

There have been a growing number of reports of such multiple pseudotumors associated with IgG4-related disease. In differential diagnosis, this disease entity requires special attention when multiple dural-based tumors are observed. Preoperative presumption is very important because this disease is likely to respond to steroid therapy.

Estimation of polyclonal IgG4 hybrids in normal human serum

The in vivo or in vitro formation of IgG4 hybrid molecules, wherein the immunoglobulins have exchanged half molecules, has previously been reported under experimental conditions. Here we estimate the incidence of polyclonal IgG4 hybrids in normal human serum and comment on the existence of IgG4 molecules with different immunoglobulin light chains. Polyclonal IgG4 was purified from pooled or individual donor human sera and sequentially fractionated using light-chain affinity and size exclusion chromatography. Fractions were analysed by SDS-PAGE, immunoblotting, ELISA, immunodiffusion and matrix-assisted laser-desorption mass spectrometry. Polyclonal IgG4 purified from normal serum contained IgG4κ, IgG4λ and IgG4κ/λ molecules. Size exclusion chromatography showed that IgG4 was principally present in monomeric form (150 000 MW). SDS-PAGE, immunoblotting and ELISA showed the purity of the three IgG4 samples. Immunodiffusion, light-chain sandwich ELISA and mass spectrometry demonstrated that both κ and λ light chains were present on only the IgG4κ/λ molecules. The amounts of IgG4κ/λ hybrid molecules ranged from 21 to 33% from the five sera analysed. Based on the molecular weight these molecules were formed of two IgG4 heavy chains plus one κ and one λ light chain. Polyclonal IgG (IgG4-depleted) was similarly fractionated according to light-chain specificity. No evidence of hybrid IgG κ/λ antibodies was observed. These results indicate that hybrid IgG4κ/λ antibodies compose a substantial portion of IgG4 from normal human serum.

IgG4-related systemic sclerosing disease: a diagnosis to be considered!!

IgG4-related systemic sclerosing disease is a chronic autoimmune disorder with diverse clinical presentation. We report a 56-year-old patient who has presented with obstructive jaundice, bulky pancreas and mesenteric lymph node mass. He was later diagnosed to have IgG4-sclerosing disease involving pancreas, small bowel mesentery, common bile duct, liver, gallbladder and submandibular salivary glands and has required multiple surgical interventions. IgG4-related systemic sclerosing disease appears to be more commonly encountered than it was once thought and needs considered in patients presenting with pancreatitis of no obvious underlying cause. Although the disease is primarily managed by medical therapy, there is a role for surgical intervention in order to obtain tissue for diagnosis, exclude other possible neoplastic aetiology and to manage disease-related complications.

Immunological diseases of the pancreatico-hepatobiliary system: update on etiopathogenesis and cross-sectional imaging findings

Immunological diseases of the hepatobiliary system and the pancreas include a broad spectrum of disorders that manifest characteristic histopathology/serology and variable clinical features and imaging findings. Recent studies have thrown fresh light on the complex role of genetics and autoimmunity in the pathogenesis and natural history of these diverse disorders that include autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, IgG4-related cholangitis, overlap/outlier syndromes, and autoimmune pancreatitis.

Autoantibodies in autoimmune pancreatitis

Autoimmune pancreatitis (AIP) was first used to describe cases of pancreatitis with narrowing of the pancreatic duct, enlargement of the pancreas, hyper-γ-globulinaemia, and antinuclear antibody (ANA) positivity serologically. The main differential diagnosis, is pancreatic cancer, which can be ruled out through radiological, serological, and histological investigations. The targets of ANA in patients with autoimmune pancreatitis do not appear to be similar to those found in other rheumatological diseases, as dsDNA, SS-A, and SS-B are not frequently recognized by AIP-related ANA. Other disease-specific autoantibodies, such as, antimitochondrial, antineutrophil cytoplasmic antibodies or diabetes-specific autoantibodies are virtually absent. Further studies have focused on the identification of pancreas-specific autoantigens and reported significant reactivity to lactoferrin, carbonic anhydrase, pancreas secretory trypsin inhibitor, amylase-alpha, heat-shock protein, and plasminogen-binding protein. This paper discusses the findings of these investigations and their relevance to the diagnosis, management, and pathogenesis of autoimmune pancreatitis.

Clinical and Immunopathologic Profile of Mexican Patients with IgG4 Autoimmune Pancreatitis

Autoimmune pancreatitis is part of the spectrum of IgG4-associated diseases. Its diagnostic criteria and histological subtypes have been formally proposed recently and although based on current data it has been suggested that there are differences in clinical presentation among populations, more research is needed to properly establish if this heterogeneity exists. In this paper, we describe 15 cases of autoimmune pancreatitis diagnosed at a Mexican centre of reference, all of them associated to the lymphoplasmocytic sclerosing pancreatitis variant. The mean age at the onset of symptoms was 47.5 ± 14.4 years, and 53% of patients were male. The main manifestations were weight loss (87%), obstructive jaundice (53%), and acute (27%) and chronic (27%) pancreatitis. Only 20% of patients had high IgG4 serum levels at the time of diagnosis. All patients receiving prednisone responded favourably, both in their pancreatic and extrapancreatic manifestations. Clinical manifestations of Mexican patients showed certain differences with respect to those usually reported.

Approach to a patient with elevated serum alkaline phosphatase

Cholestasis develops either from a defect in bile synthesis, impairment in bile secretion, or obstruction to bile flow, and is characterized by an elevated serum alkaline phosphatase and gamma-glutamyltransferase disproportionate to elevation of aminotransferase enzymes. Key elements to the diagnostic workup include visualization of the biliary tree by cholangiography and evaluation of liver histology. The hope is that recent advances in understanding the genetic factors and immune mechanisms involved in the pathogenesis of cholestasis will lead to newer therapeutic interventions in the treatment of these diseases.

Serum BAFF and APRIL levels in patients with IgG4-related disease and their clinical significance

INTRODUCTION

B cell-activating factor of the tumor necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) play a crucial role in B cell development, survival, and antibody production. Here we analyzed the serum levels of BAFF and APRIL and their respective clinical associations in patients with an immunoglobulin (Ig) G4-related disease (IgG4-RD).

METHODS

We measured serum levels of BAFF and APRIL in patients with IgG4-RD, primary Sjögren's syndrome (pSS), and healthy individuals. Serum BAFF and APRIL levels in IgG4-RD were assessed for correlations with serological parameters, including Ig, particularly IgG4, and the number of affected organs. Serum BAFF and APRIL levels in IgG4-RD were monitored during glucocorticoid (GC) therapy.

RESULTS

Serum BAFF and APRIL levels in patients with IgG4-RD were significantly higher (P < 0.01) than in healthy individuals. The BAFF levels of patients with IgG4-RD were comparable to those of patients with pSS. Although clinical parameters, such as serum IgG4 and the number of affected organs, were not correlated with the levels of BAFF, serum APRIL levels were inversely correlated with serum IgG4 levels (r = -0.626, P < 0.05). While serum BAFF levels decreased following GC therapy, serum APRIL levels increased during follow-up.

CONCLUSION

These results indicate that BAFF and APRIL might be useful markers for predicting disease activity in IgG4-RD. Further studies are needed to elucidate the role of BAFF and APRIL in the pathogenesis of IgG4-RD.

Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011

BACKGROUND

IgG4-related disease (IgG4-RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4+ plasma cells. Although IgG4-RD is not rare and is clinically important, its clinical diagnostic criteria have not been established. Comprehensive diagnostic criteria for IgG4-RD, including the involvement of various organs, are intended for the practical use of general physicians and nonspecialists.

METHODS

Two IgG4-RD study groups, the Umehara and Okazaki teams, were organized by the Ministry of Health, Labor and Welfare Japan. As IgG4-RD comprises a wide variety of diseases, these groups consist of physicians and researchers in various disciplines, including rheumatology, hematology, gastroenterology, nephrology, pulmonology, ophthalmology, odontology, pathology, statistics, and basic and molecular immunology throughout Japan, with 66 and 56 members of the Umehara and Okazaki teams, respectively. Collaborations of the two study groups involved detailed analyses of clinical symptoms, laboratory results, and biopsy specimens of patients with IgG4-RD, resulting in the establishment of comprehensive diagnostic criteria for IgG4-RD.

RESULTS

Although many patients with IgG4-RD have lesions in several organs, either synchronously or metachronously, and the pathological features of each organ differ, consensus has been reached on two diagnostic criteria for IgG4RD: (1) serum IgG4 concentration >135 mg/dl, and (2) >40% of IgG+ plasma cells being IgG4+ and >10 cells/high powered field of biopsy sample. Although the comprehensive diagnostic criteria are not sufficiently sensitive for the diagnosis of type 1 IgG4-related autoimmune pancreatitis (IgG4-related AIP), they are adequately sensitive for IgG4-related Mikulicz's disease (MD) and kidney disease (KD). In addition, the comprehensive diagnostic criteria, combined with organ-specific diagnostic criteria, have increased the sensitivity of diagnosis to 100% for IgG4-related MD, KD, and AIP.

CONCLUSION

Our comprehensive diagnostic criteria for IgG4-RD are practically useful for general physicians and nonspecialists.

Comparison of CT findings of biliary tract changes with autoimmune pancreatitis and extrahepatic bile duct cholangiocarcinoma

PURPOSE

To retrospectively evaluate criteria for differentiating biliary tract changes in autoimmune pancreatitis (AIP-BTC) from extrahepatic cholangiocarcinoma (ECCA) based on CT findings and to determine predictors for differentiation between the two disorders.

MATERIALS AND METHODS

CT findings of 22 patients with AIP-BTC and 45 patients with ECCA, both with positive CT findings in the biliary system, were retrospectively assessed. The images were assessed for presence of biliary obstruction, diameter of the maximally dilated biliary duct, maximum thickness of the involved duct, presence of masses inside or around the involved ducts, lengths of the biliary lesions, concentricity of wall thickening, multifocality of the lesion, and degree of lesion enhancement.

RESULTS

Compared with AIP-BTC, ECCA was significantly more frequently associated with biliary obstruction (p = 0.0037), shorter lengths of the biliary lesions (p = 0.0036), and masses (p < 0.001). No significant differences were found for other items.

CONCLUSION

Presence of obstructive dilatation of the bile ducts and intraluminal or peri-ductal masses and length of the thickened wall may help differentiate between AIP-BTC and ECCA.

Management strategies for autoimmune pancreatitis

INTRODUCTION

Autoimmune pancreatitis (AIP) is a newly developed concept for a peculiar type of pancreatitis, and at present is recognized as a pancreatic lesion reflecting IgG4-related systemic disease. It is of utmost importance to differentiate AIP from pancreatic cancer to avoid unnecessary surgery.

AREAS COVERED

The current management strategies for AIP, including its clinical features, diagnostic criteria, clinical subtypes, steroid therapy and prognosis are discussed, based on our 66 AIP cases and papers searched in PubMed from 1992 to March 2011, using the term 'autoimmune pancreatitis'. A new clinicopathological entity, an 'IgG4-related sclerosing disease' is also mentioned.

EXPERT OPINION

AIP should be considered in the differential diagnosis in elderly male patients presented with obstructive jaundice and pancreatic mass. Steroids are a standard therapy for AIP, but their regimen including maintenance therapy should be evaluated in prospective trials.