Clonal relationship between infiltrating immunoglobulin G4 (IgG4)-positive plasma cells in lacrimal glands and circulating IgG4-positive lymphocytes in Mikulicz's disease

T Cell Roles and Activity in Chronic Sclerosing Sialadenitis as IgG4-Related Disease: Current Concepts in Immunopathogenesis

IgG4-related disease is a multiorgan immunological fibroinflammatory disorder characterized by lymphoplasmacytic infiltration and fibrosis in multiple organs accompanied by high serum IgG4 levels. The salivary glands are the most common organs involved in this disease. Recently, chronic sclerosing sialadenitis affecting salivary glands, formerly known as Küttner's tumor, and Mikulicz's disease have been classified as a class of IgG4-related diseases. The etiopathobiology of IgG4-related disease is not fully understood. It has recently been hypothesized that the inflammatory and fibrotic process and the increased serum IgG4⁺ levels in IgG4-related disease are the result of an interaction between B cells and T helper cells, suggesting that T cells may play a key role in the pathogenesis of this disease. The aim of this review is to discuss the proposed roles of different T cell subsets in the pathogenesis of IgG4-related disease focusing on their roles in immunopathogenesis of IgG4-related sialadenitis.

Comprehensive analysis of protein-expression changes specific to immunoglobulin G4-related disease

BACKGROUND AND AIMS

Immunoglobulin 4 (IgG4)-related disease (IgG4-RD) is a lymphoproliferative disorder characterized by elevated serum IgG4 levels and tissue infiltration of IgG4-positive plasma cells. We analyzed the serum proteins, whose levels varied based on the disease state and treatment.

MATERIALS AND METHODS

Serum proteins from patients with IgG4-related disease and healthy subjects were resolved using two-dimensional electrophoresis, silver-stained, and scanned. Alternatively, the proteins were labeled with Cy2, Cy3, and Cy5 before electrophoresis. The proteins, whose expression differed significantly between patients and healthy individuals, and between before and after steroid treatment, were identified and validated using enzyme-linked immunosorbent assays.

RESULTS

Pre-treatment sera from patients with IgG4-related disease was characterized by increased levels of immunoglobulins such as IgG1, IgG4; inflammatory factors such as α-1 antitrypsin (A1AT); and proteins associated with immune system regulation such as clusterin and leucine-rich α-2-glycoprotein (LRG-1). The serum levels of A1AT, LRG-1 and clusterin, during treatment with prednisolone for up to 12 months revealed that LRG-1 levels were halved after 1 month of treatment, comparable to those in healthy subjects; LRG-1 levels remained normal until the end of treatment.

CONCLUSION

LRG-1 could serve as a novel biomarker of IgG4-related diseases.

Increased Expression of Activation-Induced Cytidine Deaminase in Sinus Mucosa from IgG4-Related Disease Patients with Comorbid Chronic Rhinosinusitis

OBJECTIVE

IgG4-related disease (IgG4-RD) is a systemic condition characterized by an elevated serum IgG4 level, localized infiltration of IgG4-positive plasma cells, and lesions in various organs. IgG4-RD also shows high rates of complication with allergic diseases and is often accompanied by elevated serum IgE levels. Reports in recent years have also shown high rates of complication with chronic rhinosinusitis (CRS) and its characteristic nasal manifestations. Accordingly, we speculate that there may be a distinct form of CRS that, as an IgG4-RD, differs from other CRS. Here, we investigated whether the elevated levels of factors that are thought to be important in the pathogenesis of IgG4-RD are also seen in the sinus mucosa of IgG4-RD-associated CRS patients.

METHODS

Ethmoid sinus mucosa specimens from 9 IgG4-RD (6 Mikulicz disease and 3 Küttner's tumor) patients with elevated serum IgG4 and IgE and from 22 control CRS patients were examined immunohistochemically for Treg cytokines (IL-10 and TGF-β), activation-induced cytidine deaminase (AID), and immunocompetent cells. The 22 control CRS patients were divided into 3 subgroups based on the serological findings for IgG4 and IgE. Quantitative real-time PCR was performed to examine the expression of AID.

RESULTS

The ethmoid sinus mucosa from patients with IgG4-RD-associated CRS showed, in comparison with the 3 CRS control subgroups, significantly elevated AID production. Their mucosa also showed significantly increased infiltration of CD-20-positive immunocompetent cells compared with the controls. On the other hand, immunohistochemical examination found no significant differences in the number of IL-10- or TGF-β-positive cells.

CONCLUSION

Ethmoid sinus mucosa from IgG4-RD-associated CRS patients showed clearly increased AID production, suggesting AID involvement in class-switching to IgG4 in those local sites. This implies the existence of a distinct form of CRS that is an IgG4-RD.

The Expression of IgG and IgG4 in Orbital MALT Lymphoma: The Similarities and Differences of IgG4-Related Diseases

Objective

This study aims to study the expression and role of IgG and IgG4 in orbital MALT lymphoma and to compare the characteristics of IgG4-related diseases.

Patients and Methods

Patients with orbital MALT lymphoma, treated in the West China Hospital of Sichuan University from 2012 to 2017, were enrolled in the current study. The immunological examination of the wax blocks of orbital masses was performed again and the expression level of IgG and IgG4 in pathological tissue was analyzed.

Results

The results presented that the positive rates of IgG and IgG4 in the cases of orbital MALT lymphoma were 90.91% and 61.98% respectively, of which IgG4/IgG >40% accounted for 49.33%. The positive rates of IgG and IgG4 in relapse cases were 94.60% and 70.27% respectively, and IgG4/IgG >40% accounted for 42.31%. There was no significant change in the expression of IgG and IgG4 in cases of lymphoproliferation converting to MALT lymphoma whereas, in cases of MALT lymphoma postoperatively converting to lymphoproliferation, there was an increase in IgG and IgG4 expression, with the change of IgG4 being significant.

Conclusion

IgG and IgG4 have a high correlation in the pathogenesis of MALT lymphoma and may even play an important role in the transformation of MALT lymphoma into orbital lymphoid hyperplasia. Given the association of IgG4 with inflammation and tumors and as an important diagnostic indicator for IgG4-RD and IgG4-related ophthalmic diseases, IgG4 may play an important role in these diseases.

Up-regulation of activation-induced cytidine deaminase and its strong expression in extra-germinal centres in IgG4-related disease

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a systemic disorder involving benign mass formation due to fibrosis and intense lymphoplasmacytosis; the chronic inflammation associated with the disease might also contribute to oncogenesis. Activation-induced cytidine deaminase (AID), normally expressed in germinal centre activated B-cells, is an enzyme that edits DNA/RNA and induces somatic hypermutation and Ig class switching. AID expression is strictly controlled under physiological conditions; however, chronic inflammation and some infectious agents induce its up-regulation. AID is overexpressed in various cancers and may be important in chronic inflammation-associated oncogenesis. We examined AID expression in IgG4-related sialadenitis (n = 14), sialolithiasis (non-specific inflammation, n = 13), and normal submandibular glands (n = 13) using immunohistochemistry and quantitative real-time polymerase chain reaction (qPCR). Immunohistochemistry revealed significantly more AID-expressing cells in IgG4-related sialadenitis than in sialolithiasis or normal submandibular gland samples (P = 0.02 and P < 0.01, respectively); qPCR yielded similar results. Thus, AID was significantly more up-regulated and had higher expression in extra-germinal centres in IgG4-RD than in non-specific inflammation or normal conditions. This report suggests that IgG4-RD has several specific causes of AID up-regulation in addition to inflammation. Furthermore, chronic inflammation-associated AID-mediated oncogenesis is possible in IgG4-RD.

LatY136F knock-in mouse model for human IgG4-related disease

Background

The adaptor protein Linker for activation of T cell (LAT) is a key signaling hub used by the T cell antigen receptor. Mutant mice expressing loss-of-function mutations affecting LAT and including a mutation in which tyrosine 136 is replaced by a phenylalanine (Lat^Y136F) develop lymphoproliferative disorder involving T helper type 2 effector cells capable of triggering a massive polyclonal B cell activation that leads to hypergammaglobulinemia G1 and E and to non-resolving inflammation and autoimmunity. The purpose of this study was to evaluate whether the phenotypes of Lat^Y136F knock-in mice resemble the immunohistopathological features of immunoglobulin G4-related disease (IgG4-RD).

Methods

Lat^Y136F knock-in mice were sacrificed at 4–20 weeks of age, and pancreas, kidney, salivary gland and lung were obtained. All organs were stained with hematoxylin-eosin and with Azan for estimation of collagen in fibrosis, and the severity scores of inflammation and fibrosis were evaluated. Immunostainings were performed to analyze the types of infiltrating cells. In addition, the effects of corticosteroid treatment on the development of tissue lesions and serum levels of IgG1 were assessed.

Results

Tissue lesions characterized by inflammatory mononuclear cell infiltration and fibrosis were detected in pancreas, kidney, and salivary gland starting from 6 weeks of age. Immunostainings showed pronounced infiltration of plasma cells, CD4-positive T cells, and macrophages. Infiltrating plasma cells predominantly expressed IgG1. The extent of inflammation in pancreas and salivary glands was markedly reduced by corticosteroid treatment.

Conclusions

Lat^Y136F knock-in mice displayed increased production of Th2-type IgG1 (a homologue of human IgG4) and developed multiple organ tissue lesions reminiscent of those seen in patients with IgG4-RD. Moreover, the development of these tissue lesions was highly sensitive to corticosteroid treatment like in IgG4-RD. For these reasons we consider the Lat^Y136F knock-in mouse strain to represent a promising model for human IgG4-RD.

B cell receptor signaling pathway involved in benign lymphoepithelial lesions of the lacrimal gland

AIM

To detect the expression of B cell receptor signaling pathway (BCRSP) in lacrimal gland benign lymphoepithelial lesions (LGBLEL).

METHODS

Gene microarray was used to compare whole-genome expression in lacrimal gland tissues from LGBLEL patients to tissues from orbital cavernous hemangioma (control tissues). Expression of BCRSP was confirmed by polymerase chain reaction (PCR) and immunohistochemistry.

RESULTS

The expression of 22 genes of the BCRSP increased significantly in LGBLEL patients. PCR analysis showed that CD22, CR2, and BTK were all highly expressed in LGBLEL tissues. Immunohistochemical analysis showed that CR2 protein was present in LGBLEL, but CD22 and BTK proteins were negative. CR2, CD22, and BTK were not observed in the orbital cavernous hemangiomas with either PCR or immunohistochemistry.

CONCLUSION

BCRSP might be involved in the pathogenesis of LGBLEL.

DNA Microarray Analysis of Submandibular Glands in IgG4-Related Disease Indicates a Role for MARCO and Other Innate Immune-Related Proteins

IgG4-related disease (IgG4-RD) is a novel systemic disease entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells accompanied by severe fibrosis. Although recent studies demonstrated that innate immune cells including monocytes and macrophages might promote local fibrosis and IgG4 production, the pathological mechanism remains unclear. In this study, we sought to identify the disease-associated genes, especially innate immune molecules. Gene expression was analyzed by DNA microarray in submandibular glands (SMGs) from patients with IgG4-RD (n = 5), chronic sialoadenitis (CS) (n = 3), and controls (n = 3). Differentially expressed genes (DEGs) were validated by real-time polymerase chain reaction (PCR) and immunohistochemical staining in IgG4-RD (n = 18), CS (n = 4), Sjögren syndrome (n = 11), and controls (n = 10). Gene expression patterns in the 3 groups were quite different from each other by the pvclust method and principal components analysis. In IgG4-RD, 1028 upregulated genes and 692 downregulated genes were identified as DEGs (P < 0.05). Gene Ontology (GO) term analysis indicated that the upregulated DEGs in IgG4-RD encoded proteins involved in T/B cell activation and chemotaxis. PCR validated significantly higher expression of macrophage receptor with collagenous structure (MARCO), a pattern-recognition receptor, in IgG4-RD compared with the other groups (P < 0.01). Immunohistochemical analysis confirmed that the expression pattern of MARCO was similar to that of the M2 macrophage marker CD163. MARCO was identified as a disease-associated molecule in IgG4-RD by DNA microarray. Moreover, M2 macrophages might contribute to the initiation of IgG4-RD via MARCO.

Association of TCR-signaling pathway with the development of lacrimal gland benign lymphoepithelial lesions

AIM

To identify the association of the T cell receptor (TCR) signaling with the development of benign lymphoepithelial lesions (BLEL) of the lacrimal gland.

METHODS

We collected affected lacrimal gland tissues from 9 patients who underwent dacryoadenectomy in the Capital Medical University Beijing Tongren Hospital Eye Center between August 2010 and March 2013 and were confirmed to have lacrimal gland BLEL by histopathological analysis. Tumor tissues from 9 patients with orbital cavernous hemangioma were also collected and used as control. Whole genome gene expression microarray was used to compare gene expression profiles of affected lacrimal gland tissues from patients with lacrimal gland BLEL to those from of orbital cavernous hemangiomas. Differential expression of TCR pathway genes between these tissues was confirmed by polymerase chain reaction (PCR) and immunohistochemistry.

RESULTS

Microarray analysis showed that in lacrimal glands with BLEL, 32 signaling pathways were enriched in the upregulated genes, while 25 signaling pathways were enriched in the downregulated genes. In-depth analysis of the microarray data showed that the expression of 27 genes of the TCR signaling pathway increased significantly. To verify the differential expression of three of these genes, CD3, CD4, and interleukin (IL)-10, reverse transcription-PCR (RT-PCR) and immunohistochemistry assays were performed. RT-PCR analysis showed that CD3 and CD4 were expressed in the lacrimal glands with BLEL, but IL-10 was not expressed. Immunohistochemistry confirmed that CD3 and CD4 proteins were also present, but IL-10 protein was not. CD3, CD4, or IL-10 expression was not found in the orbital cavernous hemangiomas with either RT-PCR or immunohistochemistry.

CONCLUSION

TCR signaling pathway might be involved in the pathogenesis of lacrimal gland BLEL.

Serum trypsin and TCR as novel markers for predicting disease activity in IgG4-related disease

Background

IgG4-related disease (IgG4-RD) is a novel disease named in recent years. Because of its varied clinical manifestations, like tumor but not tumor, it brings a great challenge to clinical diagnosis. Trypsin and T-cell receptor (TCR) are thought to mediate the regulation of B cell maturation, survival and antibody production. In this study, we investigated the clinical features and important novel markers of IgG4-RD.

Material and methods

A prospective cohort study of 22 patients with IgG4-RD was carried out from May 2009 to December 2012, and 65 cases with acute pancreatitis, 60 cases with pancreatic cancer and 120 healthy individuals were studied as controls. Serum TCR, trypsin and IgG4 levels were measured during pre- and post-treatment in the patients with IgG4-RD and their correlations with IgG4 were also assessed.

Results

Serum IgG4 and IgE levels in all patients were significantly increased, and tumor markers (carbohydrate antigen 19-9 and/or carbohydrate antigen 125) were also increased (12/22). Serum trypsin in patients with IgG4-RD was lower than in the ones with acute pancreatitis, pancreatic cancer, and healthy individuals. But serum TCR of IgG4-RD was significantly higher than in the pancreatic cancer group and normal controls and it was inversely correlated with the levels of IgG4 (r = –3.160, p = 0.042).

Conclusions

The results indicate that serum TCR and trypsin might be useful markers for predicting disease activity in IgG4-RD.

IgG4-related orbital disease: a meta-analysis and review

IgG4-related orbital disease (IgG4-ROD) is a recently described condition that may account for a significant proportion of idiopathic lymphoplasmacytic or sclerotic orbital lesions. This study is the first meta-analysis of published cases and reveals several differences between IgG4-related disease affecting the orbit and that affecting the pancreas. IgG4-ROD affects a slightly younger group of patients, affects men and women approximately equally, is commonly associated with salivary gland lesions, is associated with a relatively higher serum IgG4 and may confer an increased risk of non-Hodgkin Lymphoma. Its pathogenesis may involve an immune response to antigen exposure in the upper aerodigestive tract.

IgG4-related disease of the head and neck: CT and MR imaging manifestations

Immunoglobulin G4 (IgG4)-related disease is a recently established systemic disease that commonly involves the head and neck, including the salivary glands, lacrimal glands, orbits, thyroid gland, lymph nodes, sinonasal cavities, pituitary gland, and larynx. Although the definitive diagnosis of IgG4-related disease requires histopathologic analysis, elevated serum IgG4 levels are helpful in making the diagnosis. Because of the proposed clinical diagnostic criteria for this disease, cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance (MR) imaging play an important diagnostic role. CT and MR imaging findings of IgG4-related disease are usually nonspecific. At CT, involved organs may demonstrate enlargement or decreased attenuation; at T2-weighted MR imaging, they may have relatively low signal intensity owing to their increased cellularity and amount of fibrosis. Some pathologic entities involving the head and neck are now considered to be part of the IgG4-related disease spectrum, including idiopathic orbital inflammatory syndrome (inflammatory pseudotumor), orbital lymphoid hyperplasia, Mikulicz disease, Küttner tumor, Hashimoto thyroiditis, Riedel thyroiditis, and pituitary hypophysitis. Because involvement of multiple sites is common in IgG4-related disease, radiologists should be familiar with manifestations of this systemic process outside the head and neck, in organs such as the pancreas, bile ducts, gallbladder, kidneys, retroperitoneum, mesentery, lungs, gastrointestinal tract, and blood vessels. Moreover, IgG4-related disease usually demonstrates a dramatic response to corticosteroid therapy, and radiologists should be familiar with its clinical and imaging manifestations to avoid a delay in diagnosis or unnecessary invasive interventions.

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.

Analysis of VH gene rearrangement and somatic hypermutation in type 1 autoimmune pancreatitis

Type 1 autoimmune pancreatitis (AIP) is the pancreatic manifestation of systemic fibroinflammatory disease called immunoglobulin G4-associated systemic disease. Although this inflammatory process is considered to be a disease with an autoimmune mechanism, its pathogenesis still remains unclear. To clarify the characteristics of B cells infiltrating the lesion, we analyzed the immunoglobulin heavy chain variable region (VH) gene rearrangement and somatic hypermutation of invasive lymphoid cells in type 1 AIP (n= 3), in comparison with obstructive pancreatitis (n= 3) as a control. DNA was extracted from the affected inflammatory lesions. After PCR amplification of the rearranged VH gene, the clones were subcloned, and recombinant clones were randomly selected and sequenced. More than 60 clones per case were analyzed. Monoclonal VH rearrangement was not detected in any of the cases examined. There was no VH family or VH fragment specific to type 1 AIP and obstructive pancreatitis. However, the rate of unmutated VH fragments in type 1 AIP (17%) was higher than that in obstructive pancreatitis (5.1%) (P= 0.010). Our study suggests that an increased rate of unmutated or less mutated VH genes may be characteristic of type 1 AIP and might play a role in the development of this disease.

IgG4-related sclerosing disease: autoimmune pancreatitis and extrapancreatic manifestations

Autoimmune pancreatitis is the pancreatic manifestation of IgG4-related sclerosing disease, which recently was recognized as a distinct disease entity. Numerous extrapancreatic organs, such as the bile ducts, gallbladder, kidneys, retroperitoneum, thyroid, salivary glands, lung, mediastinum, lymph nodes, and prostate may be involved, either synchronously or metachronously. Most cases of autoimmune pancreatitis are associated with elevated serum IgG4 levels; extensive IgG4-positive plasma cells; and infiltration of lymphocytes into various organs, which leads to fibrosis. There are several established diagnostic criteria systems that are used to diagnose autoimmune pancreatitis and that rely on a combination of imaging findings of the pancreas and other organs, serologic findings, pancreatic histologic findings, and response to corticosteroid therapy. It is important to recognize multiorgan involvement of IgG4-related sclerosing disease and be familiar with its clinical and imaging features because it demonstrates a favorable response to treatment.

[A case of POEMS syndrome with enlarged pancreas due to IgG4-related autoimmune pancreatitis]

A 57-year-old man developed bilateral hands and feet numbness, followed by weakness with the legs and skin pigmentation. These symptoms became gradually worsened, and we made a diagnosis of POEMS syndrome because of progressive polyneuropathy, skin changes, IgG lambda type monoclonal proteinemia, and elevated level of serum vascular endothelial growth factor (VEGF). Diffusely enlarged pancreas was noticed in computed tomography. Serological, radiological, and histological findings revealed enlarged pancreas was due to IgG4-related autoimmune pathogenesis. After high dose chemotherapy with autologous peripheral stem cell transplantation, his clinical manifestations, IgG lambda type monoclonal proteinemia, and elevated level of serum VEGF were improved, whereas diffuse enlargement of the pancreas did not change. This is the first case report of POEMS syndrome accompanied with IgG4-related autoimmune pancreatitis. Co-existence of monoclonal and polyclonal plasma proliferative changes in the present patient may provide keys to clarify common mechanisms shared by these two rare disorders, POEMS syndrome and IgG4-related autoimmune disease.

Infraorbital nerve swelling associated with autoimmune pancreatitis

PURPOSE

The aim of our study was to examine the relation between autoimmune pancreatitis (AIP) and infraorbital nerve swelling.

MATERIALS AND METHODS

A total of 11 AIP patients underwent magnetic resonance imaging (MRI) examination of the head and neck region. The infraorbital nerve thicknesses were measured on coronal images and compared with those of a control group. We also examined whether the infraorbital nerve thicknesses were altered from before to after steroid therapy in nine patients who underwent MRI examination after such therapy.

RESULTS

The mean thicknesses were 3.8 ± 2.0 mm in the AIP group and 2.6 ± 0.5 mm in the control group (P < 0.05). The nerve thicknesses were >5 mm in 5 of 11 patients (45%) in the AIP group, and <5 mm in all of the control group. Among the nine patients who underwent MRI examination after steroid therapy, three had shown nerve swelling before steroid therapy; the therapy diminished the swelling in all three patients.

CONCLUSION

Infraorbital nerve swelling was observed more frequently in AIP patients than in patients without a history of AIP. Therefore, such swelling seems to be an extrapancreatic lesion of AIP.

IgG4-related tubulointerstitial nephritis and hepatic inflammatory pseudotumor without hypocomplementemia

Immunoglobulin G4 (IgG4)-related tubulointerstitial nephritis (TIN) is often accompanied by autoimmune pancreatitis (AIP) or chronic sclerosing dacryoadenitis and sialoadenitis. However, IgG4-related TIN without AIP or lacrimal and/or salivary gland lesions has not been well recognized. Here, we report a case of IgG4-related TIN associated with hepatic inflammatory pseudotumor without AIP or lacrimal and/or salivary gland lesions. A 58-year-old Japanese man with epigastralgia underwent contrast-enhanced computed tomography (CT), which revealed multiple low-density lesions in both kidneys and a low density hepatic mass. Laboratory tests showed an extremely high level of serum IgG4. Percutaneous renal and hepatic biopsies showed diffuse infiltration of lymphocytes and IgG4-positive plasma cells with fibrosis in both tissues. Two months after administration of oral prednisolone, both lesions decreased in size on follow-up CT, and the serum creatinine level also improved. No recurrence has been detected for two years with a maintenance dose of prednisolone.

IgG4-related diseases including Mikulicz's disease and sclerosing pancreatitis: diagnostic insights

Since the first report of serum IgG4 elevation in sclerosing pancreatitis in 2001, various systemic disorders have been reported to elevate IgG4, and many names have been proposed from the perspective of the systemic condition. Despite similarities in the organs damaged in IgG4-related Mikulicz's disease and Sjögren's syndrome, there are marked clinical and pathological differences between the 2 entities. The majority of cases diagnosed with autoimmune pancreatitis in Japan are IgG4-related sclerosing pancreatitis, and it should be recognized that this is distinct from the Western type. Diagnosis of IgG4-related disease is defined by both elevated serum IgG4 (> 1.35 g/l) and histopathological features, including lymphocyte and IgG4+ plasma cell infiltration (IgG4+ plasma cells/IgG+ plasma cells > 50% on a highly magnified slide checked at 5 points). Differential diagnosis from other distinct disorders is necessary: these include sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, cancer, and other existing conditions. The Japanese IgG4 research group has begun multicenter prospective studies to improve diagnostic criteria and treatment strategies.

A case of Mikulicz's disease, IgG4-related plasmacytic syndrome, successfully treated by corticosteroid and mizoribine, followed by mizoribine alone

We report a case of Mikulicz's disease, IgG4-related plasmacytic syndrome, successfully treated with corticosteroid and mizoribine, followed by mizoribine alone. A 56-year-old woman experienced persistent bilateral swelling in the eyelids and submandibular region accompanied by lymphadenopathy without pain. The patient was diagnosed as having Mikulicz's disease since her bilateral lacrimal glands showed persistent swelling and biopsy specimens of the submandibular glands and lymph node showed diffuse infiltration of lymphocytes and plasma cells. Symptoms and laboratory data were improved with corticosteroids (30 mg). However, after tapering prednisolone to 5 mg, submandibular swelling developed. Adding mizoribine resulted in clinical improvement. Prednisolone was tapered and finally discontinued. Since the levels of IgG4 in peripheral blood were increased even after corticosteroid therapy and IgG4 was positive in a submandibular gland specimen obtained before the start of corticoid therapy. Thus, this case may be associated with IgG4. The present case is the first case in which mizoribine was effective for Mikulicz's disease and IgG4-related plasmacytic syndrome.

[IgG4-related disease-the diagnostic confusion and how to avoid it]

Since Hamano et al. have first reported serum IgG4 elevation in sclerosing pancreatitis in 2001, various systemic disorders have been reported to be related to elavated IgG4, and many names have been proposed from the point of view of the systemic condition. Despite similarities in the organs damaged in IgG4-related Mikulicz's disease and Sjögren's syndrome, there are marked clinical and pathological differences between the two entities. IgG4-related Mikulicz's disease and Küttner's tumor are related diseases and complete differentiation is very difficult. The majority of cases diagnosed with autoimmune pancreatitis in Japan are IgG4-related sclerosing pancreatitis, and it should be recognized that this is distinct from the western type. There is a likelihood that cases once diagnose as Castleman's disease that showed good responsiveness to glucocorticoid treatment may have been IgG4-related lymphadenopathy, and should be re-assessed in light of recent findings. Diagnosis of IgG4-related disease is defined by both 1) Elevated serum IgG4 (>135 mg/dl) and 2) Histopathological features including lymphocyte and IgG4(+) plasma cell infiltration (IgG4(+) plasma cells/IgG(+) plasma cells >50% on a highly-magnified slide checked in five points), however differential diagnosis from other distinct disorders, such as sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, cancer, and other existing conditions is necessary. To avoid diagnostic confusion, simpler and more scientific names should be used where disease-specific pathogenesis or markers have been ascertained.

Nonneoplastic mimickers of pancreatic neoplasms

CONTEXT

A variety of nonneoplastic conditions may form pancreatic masses that mimic carcinoma. Approximately 5% to 10% of pancreatectomies performed with the clinical diagnosis of pancreatic cancer prove on microscopic evaluation to be pseudotumors.

OBJECTIVES

To illustrate the clinical and pathologic characteristics of the 2 most frequent pseudotumoral inflammatory conditions, autoimmune pancreatitis and paraduodenal pancreatitis, and describe the criteria that may be useful in the differential diagnosis versus pancreatic carcinoma.

DATA SOURCES

Recent literature and the authors' experience with the clinical and pathologic characteristics of autoimmune pancreatitis and paraduodenal pancreatitis.

CONCLUSIONS

The knowledge of the clinical, radiologic, and pathologic findings in both autoimmune pancreatitis and paraduodenal pancreatitis is crucial in making the correct preoperative diagnosis. Autoimmune pancreatitis, which occurs in isolated or syndromic forms, is characterized by a distinctive fibroinflammatory process that can either be limited to the pancreas or extend to the biliary tree. Its correct preoperative identification on biopsy material with ancillary immunohistochemical detection of dense immunoglobulin G4-positive plasma cell infiltration is possible and crucial to prevent major surgery and to treat these patients with steroid therapy. Paraduodenal pancreatitis is a special form of chronic pancreatitis that affects young males with a history of alcohol abuse and predominantly involves the duodenal wall in the region of the minor papilla. Pathogenetically, the anatomical and/or functional obstruction of the papilla minor, resulting from an incomplete involution of the intraduodenal dorsal pancreas, associated with alcohol abuse represents the key factor. Endoscopic drainage of the papilla minor, with decompression of the intraduodenal and dorsal pancreas, might be considered in these patients.