Yoh Zen

Consensus statement on the pathology of IgG4-related disease.

IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; and—often but not always—elevated serum IgG4 concentrations. An international symposium on IgG4-related disease was held in Boston, MA, on 4–7 October 2011. The organizing committee comprising 35 IgG4-related disease experts from Japan, Korea, Hong Kong, the United Kingdom, Germany, Italy, Holland, Canada, and the United States, including the clinicians, pathologists, radiologists, and basic scientists. This group represents broad subspecialty expertise in pathology, rheumatology, gastroenterology, allergy, immunology, nephrology, pulmonary medicine, oncology, ophthalmology, and surgery. The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4+ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum.

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

Immunoglobin G (IgG) 4‐related sclerosing pancreatitis and cholangitis (autoimmune pancreato‐cholangitis [AIPC]) are recently recognized disease entities characterized by high serum IgG4 concentrations and sclerosing inflammation with numerous IgG4‐positive plasma cells, although the underlining immune mechanism remains only speculative. In this study, the immunopathogenesis of AIPC was examined with respect to the production of cytokines in situ and the possible involvement of regulatory T cells (Tregs) using fresh (5 cases) and formalin‐fixed (28 cases) specimens of AIPC and related extra‐pancreatobiliary lesions. Quantitative real‐time polymerase chain reaction revealed that AIPC and extra‐pancreatobiliary lesions had significantly higher ratios of interleukin (IL)‐4/interferon‐γ (IFN‐γ) (45.8‐fold), IL‐5/IFN‐γ (18.7‐fold), IL‐13/interferon (IFN)‐γ (20.7‐fold), IL‐10/CD4 (45.3‐fold), and tumor growth factor (TGF)‐β/CD4 (39.4‐fold) than did primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC). Lymphocytes with signals for IL‐4 and IL‐10 were frequently found in AIPC by in situ hybridization. The expression of Foxp3 messenger RNA, a transcription factor specific for naturally arising CD4+CD25+ Tregs, was significantly increased in AIPC and extra‐pancreatobiliary lesions in comparison to PSC and PBC (36.4‐fold). Immunohistochemically, CD4+CD25+Foxp3+ cells were frequently found in AIPC, while few were found in PSC and other disease controls. Taken together, AIPC could be characterized by the over‐production of T helper (Th) 2 and regulatory cytokines. Tregs might be involved in the in situ production of IL‐10 and TGF‐β, which could be followed by IgG4 class switching and fibroplasia. Conclusion: AIPC is a unique inflammatory disorder characterized by an immune reaction predominantly mediated by Th2 cells and Tregs. (HEPATOLOGY 2007.)

Proposal for a new clinical entity, IgG4-positive multiorgan lymphoproliferative syndrome: analysis of 64 cases of IgG4-related disorders

Background: Mikulicz’s disease (MD) has been considered as one manifestation of Sjögren’s syndrome (SS). Recently, it has also been considered as an IgG4-related disorder. Objective: To determine the differences between IgG4-related disorders including MD and SS. Methods: A study was undertaken to investigate patients with MD and IgG4-related disorders registered in Japan and to set up provisional criteria for the new clinical entity IgG4-positive multiorgan lymphoproliferative syndrome (IgG4+MOLPS). The preliminary diagnostic criteria include raised serum levels of IgG4 (>135 mg/dl) and infiltration of IgG4+ plasma cells in the tissue (IgG4+/IgG+ plasma cells >50%) with fibrosis or sclerosis. The clinical features, laboratory data and pathologies of 64 patients with IgG4+MOLPS and 31 patients with typical SS were compared. Results: The incidence of xerostomia, xerophthalmia and arthralgia, rheumatoid factor and antinuclear, antiSS-A/Ro and antiSS-B/La antibodies was significantly lower in patients with IgG4+MOLPS than in those with typical SS. Allergic rhinitis and autoimmune pancreatitis were significantly more frequent and total IgG, IgG2, IgG4 and IgE levels were significantly increased in IgG4+MOLPS. Histological specimens from patients with IgG4+MOLPS revealed marked IgG4+ plasma cell infiltration. Many patients with IgG4+MOLPS had lymphocytic follicle formation, but lymphoepithelial lesions were rare. Few IgG4+ cells were seen in the tissue of patients with typical SS. Thirty-eight patients with IgG4+MOLPS treated with glucocorticoids showed marked clinical improvement. Conclusion: Despite similarities in the involved organs, there are considerable clinical and pathological differences between IgG4+MOLPS and SS. Based on the clinical features and good response to glucocorticoids, we propose a new clinical entity: IgG4+MOLPS.

Igg4-related Sclerosing Cholangitis With and Without Hepatic Inflammatory Pseudotumor, and Sclerosing Pancreatitis-associated Sclerosing Cholangitis: Do They Belong to a Spectrum of Sclerosing Pancreatitis?

Sclerosing cholangitis (SC) is a heterogeneous disease entity. Different etiologies such as choledocholithiasis, biliary tumor, or pericholangitis can manifest as SC. Hepatic inflammatory pseudotumor (IP) is rarely associated with SC (sclerosing cholangitis associated with hepatic inflammatory pseudotumor; SC-hepatic IP), but sclerosing pancreatitis (SP) is not infrequently associated with bile duct lesions (sclerosing pancreatitis-associated sclerosing cholangitis; SP-SC). In this study, we compared the histologic changes of hepatic hilar and extrahepatic bile duct lesions of SC (7 cases), SC-hepatic IP (5 cases), SP-SC (5 cases), and typical primary sclerosing cholangitis (PSC) (5 cases). Histologically, all SP-SC cases showed extensive and dense fibrosis with marked lymphoplasmacytic infiltration, many eosinophils, and obliterative phlebitis. Four cases of SC showed bile duct lesions similar to those of SP-SC, whereas other three cases of SC showed milder lymphoplasmacytic infiltration, scant eosinophilic cell infiltration, and no obliterative phlebitis. All SC-hepatic IP cases showed bile duct lesions identical to those of SP-SC. Immunohistochemically, many IgG4-positive plasma cells were found in the bile duct lesions of all SP-SC cases, 4 SC cases with marked lymphoplasmacytic infiltration, and all SC-hepatic IP cases. By contrast, IgG4-positive plasma cells were scarce or hardly found in the remaining 3 SC cases and all PSC cases. In conclusion, 4 SC cases and all SC-hepatic IP cases showed bile duct lesions identical to those of SP-SC, suggesting that these three conditions may be a single disease entity. Their pathogenesis may be similar or closely related to that of SP, and in that respect they may represent an IgG4-related biliary disease. They may respond to steroid therapy as SP does.

Recommendations for the nomenclature of IgG4-related disease and its individual organ system manifestations

John H. Stone, Arezou Khosroshahi, Vikram Deshpande, John K. C. Chan, J. Godfrey Heathcote, Rob Aalberse, Atsushi Azumi, Donald B. Bloch, William R. Brugge, Mollie N. Carruthers, Wah Cheuk, Lynn Cornell, Carlos Fernandez-Del Castillo, Judith A. Ferry, David Forcione, Gunter Kloppel, Daniel L. Hamilos, Terumi Kamisawa, Satomi Kasashima, Shigeyuki Kawa, Mitsuhiro Kawano, Yasufumi Masaki, Kenji Notohara, Kazuichi Okazaki, Ji Kon Ryu, Takako Saeki, Dushyant Sahani, Yasuharu Sato, Thomas Smyrk, James R. Stone, Masayuki Takahira, Hisanori Umehara, George Webster, Motohisa Yamamoto, Eunhee Yi, Tadashi Yoshino, Giuseppe Zamboni, Yoh Zen, and Suresh Chari

IgG4-related disease: a cross-sectional study of 114 cases.

IgG4-related disease has been identified in various organs, but whether or not there are organ-specific characteristics related to the etiologic factors is still unknown. Here, we carried out a cross-sectional study of 114 patients with IgG4-related disease. On the basis of the location of the lesions, the patients were classified into 5 groups: head and neck (n=23), thoracic (n=16), hepatic and pancreatobiliary (n=27), retroperitoneal (n=13), and systemic (n=35). All groups had similar clinicopathologic features in various aspects. However, there were some organ-specific features: for example, the proportion of the female patients was significantly higher in the head and neck group, serum IgG4 concentrations were significantly higher in the head/neck and systemic groups, and all kidney lesions were associated with extrarenal disease. Unique pathologic features were dense fibrosis in dacryoadenitis, numerous lymph follicles in sialadenitis and dacryoadenitis, and obliterative arteritis in lung lesions. In addition, an epithelioid granuloma and rheumatoid nodule were noted within IgG4-related lesions in 2 patients, 1 each with a history of tuberculosis and rheumatoid arthritis, respectively. Malignant tumors (2 lung cancers and 1 malignant lymphoma) were identified after the diagnosis of IgG4-related disease in 3 patients, all in the systemic group. In conclusion, this study showed organ-specific features of IgG4-related disease. Further study is necessary to conclude whether these features reflect different manifestations of a single disease entity or suggest different underlying etiologic factors.

Lipid-induced oxidative stress causes steatohepatitis in mice fed an atherogenic diet.

Recently, nonalcoholic steatohepatitis (NASH) was found to be correlated with cardiovascular disease events independently of the metabolic syndrome. The aim of this study was to investigate whether an atherogenic (Ath) diet induces the pathology of steatohepatitis necessary for the diagnosis of human NASH and how cholesterol and triglyceride alter the hepatic gene expression profiles responsible for oxidative stress. We investigated the liver pathology and plasma and hepatic lipids of mice fed the Ath diet. The hepatic gene expression profile was examined with microarrays and real‐time polymerase chain reactions. The Ath diet induced dyslipidemia, lipid peroxidation, and stellate cell activation in the liver and finally caused precirrhotic steatohepatitis after 24 weeks. Cellular ballooning, a necessary histological feature defining human NASH, was observed in contrast to existing animal models. The addition of a high‐fat component to the Ath diet caused hepatic insulin resistance and further accelerated the pathology of steatohepatitis. A global gene expression analysis revealed that the Ath diet up‐regulated the hepatic expression levels of genes for fatty acid synthesis, oxidative stress, inflammation, and fibrogenesis, which were further accelerated by the addition of a high‐fat component. Conversely, the high‐fat component down‐regulated the hepatic gene expression of antioxidant enzymes and might have increased oxidative stress. Conclusion: The Ath diet induces oxidative stress and steatohepatitis with cellular ballooning. The high‐fat component induces insulin resistance, down‐regulates genes for antioxidant enzymes, and further aggravates the steatohepatitis. This model suggests the critical role of lipids in causing oxidative stress and insulin resistance leading to steatohepatitis. (HEPATOLOGY 2007.)

IgG4-related disease

IgG4-related disease is a protean condition that mimics many malignant, infectious, and inflammatory disorders. This multi-organ immune-mediated condition links many disorders previously regarded as isolated, single-organ diseases without any known underlying systemic condition. It was recognised as a unified entity only 10 years ago. Histopathology is the key to diagnosis. The three central pathology features of IgG4-related disease are lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis. The extent of fibrosis is an important determinant of responsiveness to immunosuppressive therapies. IgG4-related disease generally responds to glucocorticoids in its inflammatory stage, but recurrent or refractory cases are common. Important mechanistic insights have been derived from studies of patients treated by B-cell depletion. Greater awareness of this disease is needed to ensure earlier diagnoses, which can prevent severe organ damage, disabling tissue fibrosis, and even death. Identification of specific antigens and T-cell clones that drive the disease will be the first steps to elucidate the pathogenesis of IgG4-related disease.

Abundant IgG4-positive plasma cell infiltration characterizes chronic sclerosing sialadenitis (Kuttner's tumor)

Chronic sclerosing sialadenitis (CSS) is a cryptogenic tumor-like condition of the salivary gland(s). While immune-mediated processes are suspected in its pathogenesis, and CSS is occasionally reported to be associated with sclerosing pancreatitis, an IgG4-related disease, the exact immunopathologic processes of CSS remain speculative. In this study, we examined the clinicopathologic findings of CSS (12 cases) in comparison with sialolithiasis (8 cases) and Sjögrens syndrome (13 cases), and tried to clarify whether CSS is an IgG4-related disease or not. Submandibular gland(s) were affected in all cases of CSS. CSS cases could be divided into two types: 5 cases were associated with sclerosing lesions in extrasalivary glandular tissue (systemic type), while only salivary gland(s) were affected in the remaining 7 cases (localized type). In the former type, which showed male predominance, bilateral salivary glands were frequently affected, and eosinophilia and elevations of γ-globulin and IgG in serum were frequently found. Histologically, all cases of CSS showed marked lymphoplasmacytic infiltration admixed with fibrosis and the destruction of glandular lobules. Obliterative phlebitis was found in the affected salivary glands in all cases of CSS. Immunohistochemically, the proportion of IgG4/IgG-positive plasma cells was more than 45% in CSS, while it was less than 5% in controls. The resemblance of the clinicopathologic features of CSS with those of sclerosing pancreatitis suggests the participation of a similar immunopathologic process with IgG4 disturbance in CSS. The abundance of IgG4-positive plasma cells in the lesions would be useful for distinguishing CSS from other forms of sialadenitis.

Biliary Papillary Tumors Share Pathological Features With Intraductal Papillary Mucinous Neoplasm of the Pancreas

Recently, attention has been drawn to papillary neoplasm of the pancreatobiliary systems. In the pancreas, the disease entity of intraductal papillary mucinous neoplasm (IPMN‐P) is widely recognized. In contrast, the pathological characteristics of biliary papillary tumors, such as biliary papilloma(tosis) and papillary cholangiocarcinoma, have not yet been well documented. In this study, we compared the pathological features and post‐operative prognosis among biliary papillary tumors (10 cases of biliary papilloma(tosis) and 22 cases of papillary cholangiocarcinoma), conventional non‐papillary cholangiocarcinoma (15 cases), and IPMN‐P (31 cases). Macroscopically, all biliary papillary tumors were characterized by the prominent intraductal papillary proliferation, and macroscopic mucin‐hypersecretion was seen in 9 of 32 cases (28%). Histologically, biliary papillary tumors consisted of three types of tumor cells (pancreaticobiliary, intestinal and gastric types), whereas only the pancreaticobiliary type was observed in non‐papillary cholangiocarcinoma. Immunohistochemically, biliary papillary tumors were characterized by the common expression of MUC2, CDX2 and cytokeratin 20. In addition, biliary papillary tumors could be associated with two types of invasive lesions: tubular adenocarcinoma (9 cases) and mucinous carcinoma (5 cases). Patients with tubular adenocarcinoma had a poor prognosis compared to non‐invasive papillary tumor or papillary tumor with mucinous carcinoma. These pathological characteristics and the survival status of biliary papillary tumors were different from those of non‐papillary cholangiocarcinoma, and rather closely resembled those of IPMN‐P. In conclusion, biliary papillary tumors may be the biliary counterpart (intraductal papillary neoplasm of the bile duct) of IPMN‐P. (HEPATOLOGY 2006;44:1333–1343.)