IgG4-positive Cells Research Articles

Cutaneous multicentric Castleman's disease mimicking IgG4-related disease

Castleman's disease, an uncommon lymphoproliferative disorder, can be difficult to differentiate from immunoglobulin (Ig) G4-related disease. The latter is typically characterized by elevated serum IgG4 levels and abundant IgG4-positive cells. However, multicentric Castleman's disease can also have elevated serum IgG4 levels and even fulfill the histological diagnostic criteria for IgG4-related disease. We present a case of cutaneous multicentric Castleman's disease mimicking IgG4-related disease. A 55-year-old Japanese woman developed erythematous and brown plaques on her back. Skin biopsy revealed regressive follicles with interfollicular plasmacytosis, and many plasma cells were positive for IgG4 (mean 263.67±79.19, range 214–355 per high power field). The IgG4-/IgG-positive cell ratios were 35.6%, 36.2%, and 48.4%, respectively, with an average of 40.6%, thus fulfilling the histological diagnostic criteria for IgG4-related disease. Furthermore, serum IgG4 level was significantly elevated (1490mg/dl; normal range: 4.8–105mg/dl). However, laboratory findings of anemia, hypoalbuminemia, polyclonal gammaglobulinemia, high C-reactive protein level, and elevated serum interleukin-6 level were consistent with hyper-IL-6 syndrome. Hence, the diagnosis of cutaneous multicentric Castleman's disease was made. In conclusion, IgG4-related disease cannot be differentiated from hyper-IL-6 syndromes on histology alone. Instead, laboratory analyses are necessary to distinguish between the two diseases.

The similarity of Type 1 autoimmune pancreatitis to pancreatic ductal adenocarcinoma with significant IgG4-positive plasma cell infiltration

High serum immunoglobulin G4 (IgG4) levels and infiltration of IgG4-positive cells are characteristic of Type 1 autoimmune pancreatitis (AIP). We previously reported that increased regulatory T cells (Tregs) may regulate IgG4 production in AIP. Although an increased serum IgG4 concentration is observed in some patients with pancreatic ductal adenocarcinoma (PDA), clarification is still necessary. We have therefore studied the correlations between IgG4-positive cells and Tregs in patients with PDA. A total of 21 PDA and nine AIP patients were enrolled in our study. The numbers and ratios of Tregs, IgG4-positive, and IgG-positive cells immunohistochemically stained with anti-Foxp3, IgG4, and IgG antibodies, respectively, were counted in three areas of resected pancreata in PDA, peritumoral pancreatitis (PT), and obstructive pancreatitis (OP). In PDA, PT, OP area, the number of IgG4-Positive cells (5.183 ± 1.061, 2.250 ± 0.431, 4.033 ± 1.018, respectively; p < 0.05) and the ratio of IgG4/IgG (0.391 ± 0.045, 0.259 ± 0.054, 0.210 ± 0.048, respectively; p < 0.05) were significantly lower than those in AIP (21.667 ± 2.436 and 0.306 ± 0.052, respectively). The numbers of IgG4-positive cells did not differ significantly among the three areas of resected pancreata examined. However, the IgG4/IgG (0.391 ± 0.045) and Foxp3/monocyte (0.051 ± 0.008) ratios in PDA area were significantly (p < 0.05) higher than those in OP area (IgG4/IgG: 0.210 ± 0.048; oxp3/monocyte: 0.0332 ± 0.005), but not in PT area. Of the 21 cases of PDA, the ratio of IgG4/IgG was >40 % in nine (43%), six (29%) and three (14%) cases in PDA, PT and OP area, respectively. Foxp3 and IgG4 were positively correlated in OP area, but not in PDA and PT area. Clinicians should be careful when basing a differential diagnosis of PDA and AIP on the numbers of IgG4-positive cells and the ratio of IgG4/IgG, especially when determined using a small biopsied sample.

IgG4-Related Sclerosing Cholangitis Mimicking Cholangiocarcinoma

IgG4-related disease has gained increased attention worldwide. While the initial focus was on autoimmune pancreatitis which was first described in Asian populations and turned out to be of relevance in Western populations too, the scope has recently broadened towards a notion of a multi-systemic disease with very diverse manifestations such as autoimmune pancreatitis, IgG4-related sclerosing cholangitis (IgG4-SC), retroperitoneal fibrosis and tubulointerstitial nephritis. IgG4-SC (also known as IgG4-associated cholangitis, IAC) represents a rare but clinically challenging differential diagnosis in patients with obstructive jaundice and proximal extra- or intrahepatic biliary strictures which can be mistaken for cholangiocarcinoma (CC). We present the case of a 79-year-old male patient who presented with obstructive jaundice and biliary strictures at the hepatic duct bifurcation without any evidence for autoimmune pancreatitis and without elevation of serum IgG4-concentrations who underwent hemihepatectomy for suspected CC. However, on histological examination of the resection specimen CC could not be confirmed. It was only after several episodes of obstructive jaundice had reoccurred that the diagnosis of IgG4-SC could be established by reexamination of the surgical specimen which showed extensive infiltration with IgG4-positive plasma cells. Appropriate medical treatment with steroids and azathioprine led to complete remission of the disease. Early recognition of IgG4-SC can save patients from potential harmful and unnecessary surgical interventions. Here we describe the clinical features of this rare case of IgG4-SC with extensive liver tissue infiltration with IgG4-positive cells but without elevated serum IgG4 concentration or evidence of autoimmune pancreatitis. We describe diagnostic criteria for IgG4-SC and review recent insights in pathophysiology and treatment options.

Significance of immunoglobulin G4 (IgG4)-positive cells in extrahepatic cholangiocarcinoma: Molecular mechanism of IgG4 reaction in cancer tissue

IgG4 reactions consisting of marked infiltration by immunoglobulin G4 (IgG4)-positive plasma cells in affected organs is found in cancer patients as well as patients with IgG4-related diseases. Notably, extrahepatic cholangiocarcinomas accompanying marked IgG4 reactions clinicopathologically mimic IgG4-related sclerosing cholangitis. The regulatory cytokine interleukin (IL)-10 is thought to induce the differentiation of IgG4-positive cells. In this study, to clarify the mechanism of the IgG4 reaction in extrahepatic cholangiocarcinoma, we investigated nonprofessional antigen-presenting cells (APCs) generating IL-10-producing regulatory T cells (anergy T cells) and Foxp3-positive regulatory cells producing IL-10. Immunohistochemistry targeting IgG4, HLA-DR, CD80, CD86, and Foxp3 was performed using 54 cholangiocarcinoma specimens from 24 patients with gallbladder cancer, 22 patients with common bile duct cancer, and eight patients with cancer of the Papilla of Vater. Moreover, a molecular analysis of Foxp3 and IL-10 was performed using a cultured human cholangiocarcinoma cell line. Consequently, 43% of the cholangiocarcinomas were found to be abundant in IgG4. Those expressing HLA-DR but lacking costimulatory molecules (CD80 and CD86) and those expressing Foxp3 detected by an antibody recognizing the N terminus accounted for 54% and 39% of cases, respectively. Moreover, the number of IgG4-positive cells was larger in these cases than in other groups. In cultured cells, the presence of a splicing variant of Foxp3 messenger RNA and the expression of IL-10 were demonstrated. Extrahepatic cholangiocarcinoma is often accompanied by significant infiltration of IgG4-positive cells. Cholangiocarcinoma cells could play the role of nonprofessional APCs and Foxp3-positive regulatory cells, inducing IgG4 reactions via the production of IL-10 indirectly and directly, respectively.

Mucosal Immune Cell Numbers and Visceral Sensitivity in Patients With Irritable Bowel Syndrome: Is There Any Relationship?

Repeated exposure to stress leads to mast cell degranulation, microscopic inflammation, and subsequent visceral hypersensitivity in animal models. To what extent this pathophysiological pathway has a role in patients with the irritable bowel syndrome (IBS) has not been properly investigated. The objective of this study was to assess the relationship between visceral hypersensitivity, microscopic inflammation, and the stress response in IBS. Microscopic inflammation of the colonic mucosa was evaluated by immunohistochemistry in 66 IBS patients and 20 healthy volunteers (HV). Rectal sensitivity was assessed by a barostat study using an intermittent pressure-controlled distension protocol. Salivary cortisol to a psychological stress was measured to assess the stress response. Compared with HV, mast cells, T cells, and macrophages were decreased in IBS patients. Similarly, λ-free light chain (FLC)-positive mast cells were decreased but not immunoglobulin E (IgE)- and IgG-positive mast cells. There were no differences between hypersensitive and normosensitive IBS patients. No relation was found between any of the immune cells studied and the thresholds of discomfort, urge, first sensation, or IBS symptoms (e.g., abdominal pain, stool-related complaints, bloating). Finally, stress-related symptoms and the hypothalamic-pituitary-adrenal-axis response to stress were not correlated with the number of mast cells or the presence of visceral hypersensitivity. Although the number of mast cells, macrophages, T cells, and λFLC-positive mast cells is decreased in IBS compared with HV, this is not associated with the presence of visceral hypersensitivity or abnormal stress response. Our data question the role of microscopic inflammation as an underlying mechanism of visceral hypersensitivity, but rather suggest dysregulation of the mucosal immune system in IBS.

Clinical features and relapse rates after surgery in type 1 autoimmune pancreatitis differ from type 2: A study of 114 surgically treated European patients

BackgroundAt the recent consensus conference on autoimmune pancreatitis (AIP) in Honolulu, we presented preliminary data from our study of surgically treated AIP patients. Our data strongly supported the separation of AIP into type 1 and type 2. Our study is based on a total of 114 surgically treated European AIP patients. Our aims were to elucidate serum IgG4 elevation, other organ involvement, relapse of disease, steroid treatment and diabetes after surgery in 114 surgically treated European AIP patients. Methods88 pancreaticoduodenectomies, 22 left-sided resections and 4 total pancreatectomies were examined. All cases were graded for granulocytic epithelial lesions, IgG4-positive cells, storiform fibrosis, phlebitis and eosinophilic granulocytes. Follow-up data were obtained from 102/114 patients, mean follow-up was 5.3 years. ResultsHistologically, 63 (55.3%) of the 114 patients fulfilled the criteria of type 1 AIP, while 51 (44.7%) patients fulfilled the criteria of type 2 AIP. Type 1 AIP patients were older and more often males than type 2 AIP patients. Elevation of serum IgG4, involvement of extrapancreatic organs, disease relapse, systemic steroid treatment and diabetes after surgery were noted more often in type 1 AIP, while inflammatory bowel disease (IBD) was observed mainly in type 2 AIP. ConclusionsHistological typing of AIP is clinically important because type 1 AIP is part of the IgG4-related disease and type 2 AIP is associated with IBD. Our data also show that relapse of disease and steroid treatment after surgery occur more frequently in type 1 than in type 2 AIP.

A case of MPO- and PR3-ANCA-positive hypertrophic cranial pachymeningitis with elevated serum IgG4

We report a case of orbital tumor and hypertrophic cranial pachymeningitis in a 64-year-old woman, who was initially suspected to have IgG4-related disease because of an elevated level of serum IgG4 at onset. However, her condition was resistant to glucocorticoid therapy, and additional cyclophosphamide was necessary to control the disease activity. Additional features included elevated levels of serum myeloperoxidase (MPO) and proteinase-3-anti-neutrophil cytoplasmic antibody (PR3-ANCA), and biopsy specimens from the orbital mass revealed very few infiltrating IgG4-positive cells. Instead, rupture of the elastic layer of the arterial walls with neovascularization and a small number of giant cells were observed. Considering these findings and the clinical course, the disease was considered more likely to be ANCA-associated pachymeningitis with elevation of the serum IgG4 level.

Light-microscopic characteristics of IgG4-related tubulointerstitial nephritis: distinction from non-IgG4-related tubulointerstitial nephritis

IgG4-related disease is a multi-organ disorder characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive cells into affected organs. In routine studies, however, IgG subclasses are not estimated. In the present study, we attempted to clarify the light-microscopic characteristics of IgG4-related tubulointerstitial nephritis (TIN) to facilitate distinction from non-IgG4-related TIN in specimens obtained by renal biopsy using routine staining. In specimens from 34 cases of TIN (13 IgG4-related and 21 non-IgG4-related), 9 nephrologists independently reviewed the following histological features of interstitial lesions: (i) cell infiltration extending into the renal capsule, (ii) cell infiltration into the renal medulla, (iii) regional lesion distribution, (iv) lymphoid follicles, (v) granulomatous lesions, (vi) necrotizing angiitis, (vii) eosinophil infiltration, (viii) neutrophil infiltration, (ix) tubulitis, (x) peritubular capillaritis, (xi) storiform fibrosis and (xii) the stage of interstitial fibrosis. The modified nominal group technique was applied to obtain a consensus in the pathological interpretation. Consensus was successfully attained among the diagnosticians for all but one pathological feature (regional lesion distribution). Storiform fibrosis was demonstrated in 12 of 13 (92.3%) cases of IgG4-related TIN but in none of the cases of other types of TIN. Cell infiltration extending into the renal capsule was also observed only in IgG4-related TIN. Conversely, neutrophil infiltration, severe tubulitis, severe peritubular capillaritis, granulomatous lesions and necrotizing angiitis were evident only in non-IgG4-related TIN. This study revealed some useful and characteristic features for distinguishing IgG4-related from non-IgG4-related TIN on the basis of light-microscopic observation.

IgG4-positive plasma cells in carcinomas of the pancreas and ampulla of vater

Aim To study the prevalence and distribution of IgG4-positive plasma cells in pancreatic and ampullary carcinoma. Method 29 cases of primary pancreatic and ampullary carcinoma between 2008 and 2011 were retrieved from archive. IgG4 staining by immunohistochemistry was performed on sections of the tumour with surrounding pancreas and pancreatic ducts. The pattern of distribution and the mean numbers of IgG4-positive plasma cells were obtained. Results 19 of 29 (66%) cases showed the presence IgG4-positive plasma and eight cases (28%) featured >30 positive cells/HPF. Six cases (21%) showed a periductal distribution of IgG4 positive plasma cell with three cases (10%) displaying >10 positive cells/HPF. Two cases (7%) showed a diffuse distribution of IgG4-positive plasma cells. Conclusion IgG4-positive plasma cells are not infrequently found in association with pancreatic and ampullary adenocarcinoma. Our study highlights the presence of both peritumoural and periductal IgG4-positive plasma cells, which may rarely be diffusely distributed, in a significant minority of pancreatic and ampullary carcinomas. It is important that clinical, radiological and pathological correlation be used in the diagnosis of autoimmune pancreatitis as IgG4-positive cells may be seen in a proportion of carcinomas.

IgG4-Related Disease without Overexpression of IgG4: Pathogenesis Implications

IgG4-related disease is a new disease group that affects multiple organs. It is characterized by high serum IgG4 and abundant infiltration of IgG4-bearing plasma cells in the affected organ. Here, we describe an intriguing case that suggested that IgG4-related disease might present without IgG4 overexpression or infiltration, at least during a relapse. A 47-year-old man had been diagnosed with systemic lupus erythematosus 15 years. He was admitted due to a pituitary mass, systemic lymphadenopathy, and multiple nodules in the lungs and kidneys. The serum IgG4 level was normal and histopathological examination of the pituitary mass showed abundant lymphocyte and plasma cell infiltration with very few IgG4-positive cells. When we examined specimens preserved from 15 years ago, we found high serum IgG4 levels and IgG4-bearing plasma cell infiltration. This resulted in a diagnosis of IgG4-related disease, and we considered the current episode to be a relapse without IgG4 overexpression. This case indicated that, to clarify the pathogenesis of IgG4-related disease, current cases should repeat specimen evaluations over the course of IgG4-related disease to define diagnostic markers.

Rosai-Dorfman Disease: Report of a Case Associated with IgG4-Related Sclerotic Lesions

We describe a rare case of sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) associated with a six-year history of autoimmune pancreatitis, which was controlled by steroid treatment. The patient presented with multiple, cervical and thoracic lymphadenopathy and abnormal, nodular opacities in the lung. Histologically, Rosai-Dorfman disease with numerous IgG4-positive cells was identified in a subcutaneous lymph node in the patient's left forearm. The patient recovered uneventfully with steroid treatment.

Ocular adnexal IgG4‐related disease: comparative analysis with mucosa‐associated lymphoid tissue lymphoma and other chronic inflammatory conditions

Making a differential diagnosis of IgG4-related disease from mucosa-associated lymphoid tissue (MALT) lymphoma or any other chronic inflammation is often challenging. Moreover, the association with secondary lymphoma of ocular adnexal IgG4-related disease needs to be elucidated. We investigated 14 cases of IgG4-related disease, nine MALT lymphomas and 12 other chronic inflammations involving the lacrimal gland and orbit. Bilateral involvement was frequent in IgG4-related diseases. The number of IgG4-positive cells and the ratio of IgG4/IgG-positive cells were higher in patients with IgG4-related disease than in those with MALT lymphoma (P = 0.016; P < 0.001) and other types of inflammation (P < 0.001; P < 0.001). Monoclonal B cell proliferation was suspected in two cases (14.3%) of IgG4-related disease. One of these patients also displayed monomorphous features suggesting secondary MALT lymphoma. In the other case, κ-chain restriction in IgG4-positive cells was observed, raising the possibility of IgG4-producing MALT lymphoma. Trisomy 3, trisomy 18 or MALT1 translocation was observed in none of the IgG4-related cases. Regulatory T-cell infiltration was higher in cases of IgG4-related disease than in MALT lymphomas (P < 0.001) and other types of inflammation (P = 0.006). Some genetically and morphologically complicated cases of ocular adnexal IgG4-related disease emphasize the need for in-depth studies to differentiate this disease from MALT lymphoma, and to exclude secondary lymphoma.

The Influence of AIDS on the Morphometric and Immune Status of the Uterine Cervix of Autopsied Patients

Previous studies have shown that HIV infection is related to changes in the immune status of the mucosal surfaces. Such changes may also occur in the genital tract, since patients infected by HIV have the virus in their cervical secretions. Fragments of the uterine cervix of 29 autopsied women were collected at a university hospital from 1985 to 2008, and were divided in groups with and without AIDS. Image J software was used to measure the cervical epithelium and to count the epithelial cellular layers. Langerhans cells (LCs) and IgG positive cells were respectively immunostained with anti-S100 and anti-IgG. Women with AIDS, when compared with women without AIDS, had thinner cervical epithelium (103.32 vs 116.71 μm), lower number of cellular layers (10.41 vs 13.66 μm), lower mean cell diameter (10.09 vs 11.51 μm), less number of total LCs (11.19 vs 23.08 LCs/mm(2)), and higher percentage of IgG positive cells (22.64% vs 16.06%). All these results were significant. AIDS causes alterations in the structure of the cervical epithelium and in its extracellular matrix, leading to alterations in the local and systemic immunity, and triggering signs and opportunistic infections in the uterine cervix in the course of the disease.

Increased Numbers of IgG4-Positive Plasma Cells May Rarely Be Seen in Lymph Nodes of Patients Without IgG4-Related Sclerosing Disease

IgG4-related sclerosing disease (IRSD) is a steroid-responsive fibroinflammatory disorder characterized by increased IgG4+ cells. Nodal involvement usually lacks the dense sclerosis seen in extranodal sites, with histologic patterns overlapping with other reactive processes. Twenty-six lymph nodes showing IRSD-related histologic patterns were evaluated for IgG and IgG4 positive cells by immunohistochemistry and correlated with the clinical features. Cases included 7 Castleman disease-like cases (type I pattern), 10 follicular hyperplasia (type II), and 9 plasmacytosis (type III). The mean numbers of IgG4+ cells per high-power field (HPF) were 4.8 (I), 8.4 (II), and 26.6(III), and the mean IgG4/IgG ratios were 0.05 (I), 0.04 (II), and 0.08 (III). Using >50 IgG4+cells/HPF and IgG4/IgG ratio of >0.4 for absolute and relative increases, only 1 case fulfilled both criteria for increased IgG4+ cells, a patient with Hashimoto's thyroiditis without clinical evidence of IRSD. The results suggest that increased IgG4+ cells may rarely be seen in non-IRSD lymph nodes.

Immunoglobulin G4-related lymphadenopathy with inflammatory pseudotumor-like features

Immunoglobulin (Ig) G4-related disease has been recently described. This disease affects various organs, including lymph nodes. We describe the case of a 52-year-old Japanese man with IgG4-related lymphadenopathy with inflammatory pseudotumor (IPT)-like features. Five years ago, the patient noticed a painless mass in the mandible but did not consult a doctor. Recently, he noted that the mass had increased in size and consulted an oral surgeon in the hospital. Excisional biopsy was performed for diagnosis. Histopathological examination revealed that most of the enlarged lymph node was occupied by the hyalinized tissue. A few residual lymphoid follicles with hyperplastic germinal centers and infiltration of plasma cells and eosinophils were observed. Most of the plasma cells expressed IgG4, and the ratio of IgG4-positive cells to IgG-positive cells was 57.1%. These findings were consistent with IgG4-related lymphadenopathy. In conclusion, pathologists should consider IgG4-related lymphadenopathy when diagnosing a lesion with IPT-like features.

Characteristic tubulointerstitial nephritis in IgG4-related disease

Nephropathy associated with IgG4-related disease is characterized by tubulointerstitial nephritis. To better identify its pathology, the present study analyzed clinicopathologic features of IgG4-related tubulointerstitial nephritis cases from across Japan. Sixteen cases were identified as IgG4-related nephropathy using the criterion of high serum IgG4 levels (>135 mg/dL) with abnormal kidney computed tomography or elevated serum creatinine levels. Male predominance (75%) and advanced age (average, 62.0 years) were noted. Eight cases displayed no autoimmune pancreatitis. Renal computed tomography abnormalities were found in 12 of 13 cases examined. Renal dysfunction was found in 15 of 16 cases at biopsy. Distinctive features of tubulointerstitial lesions included (1) well-demarcated borders between involved and uninvolved areas; (2) involvement of the cortex and medulla, often extending beyond the renal capsule and with occasional extension to retroperitoneal fibrosis; (3) interstitial inflammatory cells comprising predominantly plasma cells and lymphocytes, with a high prevalence of IgG4-positive cells often admixed with fibrosis; (4) peculiar features of interstitial fibrosis resembling a "bird's-eye" pattern comprising fibrosis among inter-plasma cell spaces; and (5) deposits visible by light and immunofluorescent microscopy in the tubular basement membrane, Bowman capsule, and interstitium that are restricted to the involved portion, sparing normal parts. Ultrastructural analysis revealed the presence of myofibroblasts with intracellular/pericellular collagen accompanied by plasma cell accumulation from an early stage. Histology could not discriminate between IgG4-related tubulointerstitial nephritis with and without autoimmune pancreatitis. In conclusion, the distinctive histologic features of IgG4-related tubulointerstitial nephritis can facilitate the differential diagnosis of tubulointerstitial nephritis, even without autoimmune pancreatitis or an abnormal computed tomography suggesting a renal tumor.

Thrombotic thrombocytopenic purpura in IgG4‐related disease with severe deficiency of ADAMTS‐13 activity and IgG4 autoantibody against ADAMTS‐13

IgG4-related disease is a recently recognized group characterized by elevated serum IgG4 levels and prominent lymphoplasmacytic infiltration of IgG4-positive cells into multiple organs (1). The condition was first described in relation to the pancreas (i.e., autoimmune pancreatitis [AIP] [2]), but since then many other inflammatory conditions associated with IgG4-related disease have been reported, including sclerosing cholangitis, sialadenitis, lymphadenopathy, retroperitoneal fibrosis, interstitial pneumonia, and tubulointerstitial nephritis (1,3,4). Laboratory findings in IgG4-related disease are commonly characterized by hypergammaglobulinemia and high levels of serum IgG and IgG4, and in addition, a high serum IgE level, peripheral eosinophilia, and hypocomplementemia are often observed (3,4). Thrombocytopenia in IgG4-related disease is rare, but a few cases of autoimmune thrombocytopenia have been reported in patients with AIP (5,6). We describe here, to our knowledge, the first case of acquired thrombotic thrombocytopenic purpura (TTP) in a patient with IgG4-related lung disease with severe deficiency of ADAMTS-13 activity and IgG4 autoantibody against ADAMTS-13.

Membranous Nephropathy Associated With IgG4-Related Disease

Immunoglobulin G4 (IgG4)-related systemic disease is a rare condition characterized by high levels of circulating IgG4 and IgG4-positive plasma cell infiltrates in various organs, including the pancreas, salivary glands, biliary tract, liver, lung, and kidney. We describe a case of a 54-year-old man with IgG4-related systemic disease presenting with autoimmune pancreatitis and Mikulicz disease. Steroid therapy decreased circulating IgG4 levels and promoted regression of clinical signs. Thereafter, an increase in serum IgG4 values was followed by the occurrence of nephrotic-range proteinuria. Kidney biopsy showed membranous nephropathy with no IgG4-positive cell infiltrates. A search for circulating immune complexes was negative, and antibodies against M-type phospholipase A(2) receptor could not be detected. Western blot analyses identified circulating IgG3 reacting with superoxide dismutase 2. This case suggests that membranous nephropathy represents an additional renal manifestation of IgG4-related systemic disease, with a pathogenesis possibly associated with neoproduction of autoantibodies targeting podocyte antigen(s).

Orbital Inflammation With IgG4-Positive Plasma Cells

To describe clinical, radiographic, and morphologic findings in patients with IgG4-positive cells present on orbital biopsy specimens. Retrospective review (from January 1, 1993, through December 31, 2006) of patients with orbital biopsy specimens that excluded lymphoma; comparison of patients with and without IgG4-positive cells on immunostaining. Of 21 patients, 11 had increased IgG4-positive cells (defined as >10 cells on biopsy). Symptoms included eyelid or periocular swelling (8 patients) or proptosis (3 patients), with bilateral involvement in 6 patients. Computed tomographic imaging displayed lacrimal gland mass in 10 patients; 6 patients had lesions in other organs. Two patients had increased serum IgG4 levels. In 10 patients without IgG4-positive cells (≤10 cells on biopsy), 6 had proptosis, 1 had eyelid swelling, 2 had eyelid mass, and 1 had diplopia, all unilateral. None had systemic symptoms. Patients with IgG4-positive cells had longer symptom duration, and their biopsy specimens showed more background fibrosis, lymphoid hyperplasia, plasma cells, and eosinophils. The clinical appearance, high incidence of bilateral disease, association with lesions in other organs, and increased IgG4 serum levels in some patients-with an increased number of IgG4-positive cells in the biopsy specimen, which shows more background fibrosis, lymphoid hyperplasia, plasma cells, and eosinophils-indicate that these patients have an orbital manifestation of IgG4-associated systemic disease.

A clinical study of olfactory dysfunction in patients with Mikulicz's disease

Objective Mikulicz's disease (MD) is differentiated from Sjögren's syndrome as an immunoglobulin G4 (IgG4) systemic disease. MD patients often report olfactory dysfunction (OD). To analyze cases of OD associated with MD, we studied clinicopathological and serological findings of MD patients. Methods A total of 44 MD patients (17 males and 27 females) were examined for OD. We evaluated clinicopathological and serological findings of these patients by dividing them into OD (+) and OD (−) groups. Results The mean IgG4 concentration (SD) in such cases was 950.5 (797.5) mg/dl. Of the 44 patients, 20 (45%) had OD even though no abnormalities, such as obstructive and inflammatory disease, were detected in their nasal cavities and sinuses. The two groups did not show significant differences in background characteristics, such as age, sex, IgG4 concentration, presence or absence of allergic rhinitis, and presence or absence of extrasalivary gland lesions. We found abundant IgG4-positive plasmacytes in the nasal mucosa specimens of the OD (+) group but not in that of the OD (−) group. Conclusions Nasal mucosa in the MD patients with OD was infiltrated with IgG4-positive plasmacytes. We concluded that OD may be associated with infiltration by IgG4-positive cells.