Autoimmune pancreatitis, Helicobacter pylori infection, and apoptosis: a proposed relationship

Research Progress in Intestinal Microecology in Pancreatic Cancer Diagnosis and Treatment

The intestinal microbiota has an increasingly recognized role in the development of cancer, in which microbial interactions play a more important than expected role. Pancreatic cancer is a highly fatal disease, in which its mortality is closely related to its morbidity. Early detection is the best chance of improving survival. Through an in-depth understanding of the pancreatic cancer microbiota, we could establish screening or early diagnosis methods for pancreatic cancer, implement bacterial treatment, adjust the therapeutic effect, and even reduce adverse reactions. These would lead to new developments and provide hope for patients with pancreatic cancer. Herein, we review the progress in intestinal microbiology research to diagnose and treat pancreatic cancer.

The Immunologic Paradoxes of IgG4-Related Disease

IgG4-related disease (IgG4-RD), which usually occurs in middle-aged and elderly men, is a newly recognized fibroinflammatory condition characterized by swelling and sclerosis of involved organs, increased IgG4-positive plasma cell infiltration in lesions, and elevated IgG4 concentration in serum. Despite growing interest in the research, the pathophysiological mechanism remains elusive. Most IgG4-RD patients respond well to steroid therapy initially, but recurrent and refractory cases are common, especially in advanced fibrotic stage. Recent studies have documented the heterogeneity of the B cell lineages, which suggests their multiple functions in IgG4-RD beyond IgG4 production, such as cytokine secretion, antigen presentation, autoantibody production, and modulation of T and B cell interactions. Thus, a critical balance exists between pathogenic and regulatory B subsets to prevent immunopathology. A prompt response to B cell depletion therapy reported in recent cases strongly suggests the imbalance within B cell lineages in IgG4-RD. A more precise understanding of the pathogenesis of IgG4-RD will open up new perspectives for therapeutic strategy. With a particular emphasis on the novel B cell-targeted therapeutic strategies, this review highlights the immunologic features of IgG4-RD and the possible roles of B cell lineages in the pathogenesis of IgG4-RD.

Detection of autoantibodies against carbonic anhydrase I and II in the plasma of patients with gastric cancer

Cancer is the second leading cause of death and gastric cancer is the fourth most common cancer type worldwide. Investigation of autoantibodies in cancer patients has been a popular research area in recent years. The aim of the current study was to investigate carbonic anhydrase I and II (CA I and II) autoantibodies in the plasma of subjects with gastric cancer based on the information and considerations of autoimmune relation of gastric cancer. Anti-CA I and II antibody levels were investigated by ELISA in plasma samples of fifty two patients with gastric cancer and thirty five healthy peers. Anti-CA I and II antibody titers of the gastric cancer group were significantly higher compared with the control group (p = 0.004, p = 0.0001, respectively). Plasma anti-CA I levels of the metastatic group were lower than the non-metastatic group and this difference was found statistically significant (p < 0.05), but there was no statistical difference between plasma anti-CA II levels of the groups. CA I and II autoantibody titers in patients with gastric cancer were found higher compared to healthy subjects and the results suggest that these autoantibodies may be involved in the pathogenesis of gastric cancer.

No evidence to support a role for Helicobacter pylori infection and plasminogen binding protein in autoimmune pancreatitis and IgG4-related disease in a UK cohort

BACKGROUND AND OBJECTIVES

Helicobacter pylori (H.pylori) plasminogen binding protein (PBP) has been proposed as an antigen triggering autoimmune pancreatitis (AIP), the pancreatic manifestation of IgG4-related disease (IgG4-RD). We investigated exposure to H. pylori infection, cytokine response and immunological memory to H. pylori PBP in a prospective IgG4-RD cohort in the UK.

METHODS

Clinical and endoscopic evidence of peptic ulceration, serological H. pylori exposure and serum IgG4 levels were obtained in 55 IgG4-RD patients and 52 disease controls (DC) with autoimmune or inflammatory conditions with an elevated serum IgG4. Gastric and duodenal tissues were assessed for H. pylori and immunostained for IgG4. B and T cell ELISpot and cytokine luminex assays were used to detect immune responses to H. pylori PBP.

RESULTS

85% of IgG4-RD patients had pancreatic and/or biliary disease, 89% had extra-pancreatic manifestations, and 84% had an increased serum IgG4. Clinical dyspepsia (35.2%), gastritis (58%), peptic ulceration (7.4%) and H. pylori colonisation (24%) in IgG4-RD was similar to DC. In IgG4-RD, gastric tissue contained a chronic inflammatory infiltrate with a low IgG4+ plasma-cell count (<10/HPF; range 1-4/HPF), and duodenal specimens had an increased IgG4 count (>10/HPF; range 7-54) compared with DC (p < 0.01). Th1 and Th2 cytokine response and immunological B-cell memory to H. pylori PBP did not differ between IgG4-RD and DC.

CONCLUSIONS

In a prospective UK cohort, the prevalence of gastric ulceration, exposure to H. pylori, cytokine response and immunological memory to H. pylori PBP did not differ in IgG4-RD patients compared with DC. This study does not support a role for H. pylori PBP as a microbial antigen in IgG4-RD.

KEYWORDS FOR ABSTRACT

Peptic ulceration, Antigens, B cells, T cells, Interleukins, Helicobacter pylori.

A high number of IgG4-positive cells in gastric cancer tissue is associated with tumor progression and poor prognosis

IgG4-related disease is a newly defined disease characterized by elevated serum IgG4 levels and infiltration of affected organs by IgG4-positive plasma cells. Recently, increased IgG4 levels were reported to be closely related with malignancy. To assess the relationship between IgG4 and the progression of gastric cancer, we immunohistochemically stained in this study gastric cancer tissue samples for IgG4-positive cells using an anti-IgG4 antibody. In addition, pre- and postoperative serum concentrations of IgG4 were measured, using an enzyme-linked immunosorbent assay. In gastric cancer samples, the number of CD138-positive plasma cells was significantly lower and the number of IgG4-positive cells significantly higher than in non-cancerous gastric mucosa. The number of IgG4-positive cells was significantly correlated with gross tumor appearance, tumor depth, lymph node metastasis, venous invasion, and lymphatic invasion. Prognosis was significantly poorer in patients with a high number of IgG4-positive cells than in those with a low number. Multivariate analysis indicated that both the number of IgG4-positive cells and the depth of tumor invasion were independently prognostic of survival. In conclusion, in gastric cancer, the number of IgG4-positive cells is increased and this is closely associated with gastric cancer progression.

Roles of Commensal Microbiota in Pancreas Homeostasis and Pancreatic Pathologies

The pancreas plays a central role in metabolism, allowing ingested food to be converted and used as fuel by the cells throughout the body. On the other hand, the pancreas may be affected by devastating diseases, such as pancreatitis, pancreatic adenocarcinoma (PAC), and diabetes mellitus (DM), which generally results in a wide metabolic imbalance. The causes for the development and progression of these diseases are still controversial; therefore it is essential to better understand the underlying mechanisms which compromise the pancreatic homeostasis. The interest in the study of the commensal microbiome increased extensively in recent years, when many discoveries have illustrated its central role in both human physiology and maintenance of homeostasis. Further understanding of the involvement of the microbiome during the development of pathological conditions is critical for the improvement of new diagnostic and therapeutic approaches. In the present review, we discuss recent findings on the behavior and functions played by the microbiota in major pancreatic diseases and provide further insights into its potential roles in the maintenance of pancreatic steady-state activities.

Immunoglobulin G4-related lung disease: a disease with many different faces

Immunoglobulin (Ig) G4-related lung disease is a fibroinflammatory entity that presents in protean ways. Diagnostically, IgG4-related lung disease requires a high clinical index of suspicion complemented by elevated serum IgG4 levels and⁄or biopsy that shows the characteristic pathological features. The disease is almost always responsive to systemic corticosteroids. However, relapse is common following their discontinuation. The authors present three cases to highlight the diverse clinical features, and to illustrate the diagnostic and therapeutic approaches to this disease.

Serum protein signatures differentiating autoimmune pancreatitis versus pancreatic cancer

Autoimmune pancreatitis (AIP) is defined by characteristic lymphoplasmacytic infiltrate, ductal strictures and a pancreatic enlargement or mass that can mimic pancreatic cancer (PaCa). The distinction between this benign disease and pancreatic cancer can be challenging. However, an accurate diagnosis may pre-empt the misdiagnosis of cancer, allowing the appropriate medical treatment of AIP and, consequently, decreasing the number of unnecessary pancreatic resections.

Mass spectrometry (MS) and two-dimensional differential gel electrophoresis (2D-DIGE) have been applied to analyse serum protein alterations associated with AIP and PaCa, and to identify protein signatures indicative of the diseases. Patients' sera were immunodepleted from the 20 most prominent serum proteins prior to further 2D-DIGE and image analysis. The identity of the most-discriminatory proteins detected, was performed by MS and ELISAs were applied to confirm their expression. Serum profiling data analysis with 2D-DIGE revealed 39 protein peaks able to discriminate between AIP and PaCa. Proteins were purified and further analysed by MALDI-TOF-MS. Peptide mass fingerprinting led to identification of eleven proteins. Among them apolipoprotein A-I, apolipoprotein A-II, transthyretin, and tetranectin were identified and found as 3.0-, 3.5-, 2-, and 1.6-fold decreased in PaCa sera, respectively, whereas haptoglobin and apolipoprotein E were found to be 3.8- and 1.6-fold elevated in PaCa sera. With the exception of haptoglobin the ELISA results of the identified proteins confirmed the 2D-DIGE image analysis characteristics. Integration of the identified serum proteins as AIP markers may have considerable potential to provide additional information for the diagnosis of AIP to choose the appropriate treatment.

IgG4 Cholangiopathy

IgG4 cholangiopathy can involve any level of the biliary tree which exhibits sclerosing cholangitis or pseudotumorous hilar lesions. Most cases are associated with autoimmune pancreatitis, an important diagnostic clue. Without autoimmune pancreatitis, however, the diagnosis of IgG4-cholangiopathy is challenging. Indeed such cases have been treated surgically. IgG4-cholangiopathy should be diagnosed based on serological examinations including serum IgG4 concentrations, radiological features, and histological evidence of IgG4(+) plasma cell infiltration. Steroid therapy is very effective even at disease relapse. A Th2-dominant immune response or the activation of regulatory T cells seems to be involved in the underlying immune reaction. It is still unknown why IgG4 levels are specifically elevated in patients with this disease. IgG4 might be secondarily overexpressed by Th2 or regulatory cytokines given the lack of evidence that IgG4 is an autoantibody.

Cure of alopecia areata after eradication of Helicobacter pylori: a new association?

Alopecia areata is a disease of the hair follicles, with strong evidence supporting autoimmune etiology. Alopecia areata is frequently associated with immune-mediated diseases with skin manifestations such as psoriasis and lichen planus, or without skin manifestations such as autoimmune thyroiditis and idiopathic thrombocytopenic purpura. Helicobacter pylori (H. pylori) infection is present in around 50% of the world's population and has been associated with a variety of immune-mediated extra-digestive disorders including autoimmune thyroiditis, idiopathic thrombocytopenic purpura, and psoriasis. A case of a 43-year old man with an 8-mo history of alopecia areata of the scalp and beard is presented. The patient was being treated by a dermatologist and had psychiatric support, without any improvement. He had a history of dyspepsia and the urea breath test confirmed H. pylori infection. The patient went into remission from alopecia areata after H. pylori eradication. If such an association is confirmed by epidemiological studies designed for this purpose, new therapeutic options could be available for these patients, especially in areas where infection with H. pylori is highly prevalent.

Pathogenesis of IgG4-related disease

PURPOSE OF REVIEW

To review studies that have examined underlying genetic and immunological aspects of IgG4-related disease.

RECENT FINDINGS

Genetic studies have suggested that several human leukocyte antigen (HLA) and non-HLA haplotypes/genotypes are associated with susceptibility to IgG4-related disease or to disease relapse after steroid therapy. Among several autoantibodies identified so far, autoantibodies against lactoferrin and carbonic anhydrase II are most frequently detected in serum of IgG4-disease patients. However, it has not been well clarified whether or not those autoantibodies belong to an IgG4 subclass. Studies that have demonstrated molecular mimicry between Helicobacter pylori and constituents of pancreatic epithelial cells suggest that gastric H. pylori infection triggers autoimmune pancreatitis in genetically predisposed individuals through antibody cross-reactivity. Recently, T-helper 2 immune reaction has been suggested to be predominant in IgG4-related disease. Interestingly, regulatory immune reactions are activated in IgG4-related disease, and regulatory cytokines interleukin-10 and transforming growth factor-b have been suggested, respectively, to play important roles in IgG4 class switch and fibroplasia.

SUMMARY

Autoimmunity has been considered the most probable pathogenesis of IgG4-related disease, but has not been completely proved so far. A breakthrough study to detect a specific autoantigen, autoantibody, or pathogen is necessary.

Helicobacter pylori in autoimmune pancreatitis and pancreatic carcinoma

BACKGROUND

Helicobacter pylori has been suggested to be involved in pancreatic diseases, namely autoimmune pancreatitis and pancreatic carcinoma. We investigated the presence of conserved sequences of Helicobacter in pancreatic tissue and pancreatic juice from patients with chronic nonautoimmune and autoimmune pancreatitis as well as pancreatic ductal adenocarcinoma (PDAC).

METHODS

35 pancreatic juices collected during routine endoscopic retrograde cholangiopancreatography and 30 pancreatic tissues were studied. Nested PCR was used to detect H. pylori in the isolated DNA samples. In order to exclude a methodological bias, the samples were analyzed blindly in 2 different laboratories using either conventional or LightCycler PCR for H. pylori urease A and 16S ribosomal DNA.

RESULTS

In the pancreas of 11 patients with autoimmune pancreatitis, no H. pylori DNA could be detected. Further, in none of the other tissue samples of chronic pancreatitis or PDAC could we detect any Helicobacter sequences. Out of the pancreatic juice samples, none demonstrated either of the 2 Helicobacter gene sequences investigated.

CONCLUSION

Despite good scientific reasoning for an involvement of Helicobacter in pancreatic diseases, a direct infection of the microbial agent seems unlikely. Rather, the pathomechanism must involve molecular mimicry in autoimmune pancreatitis, or the transformation of nitric food constituents to nitrosamines in pancreatic cancer. and IAP.

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.

[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.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.