Multiple IgG4-related sclerosing lesions in the maxillary sinus, parotid gland and nasal septum

IgG4-related sclerosing disease is recognized as a distinct clinicopathological entity. It is well known that this disease can occur in the salivary, lacrimal and pituitary glands, in the head and neck region. The nasal cavity is an extremely rare site of involvement of IgG4-related sclerosing disease. Herein is reported a case of multiple IgG4-related sclerosing lesions in the maxillary sinus, parotid gland and nasal septum. A 73-year-old Japanese man presented with nasal obstruction and tumors of the right maxillary sinus and parotid gland were detected, after which resections of these tumors were performed. One year after the last surgery, he noted swelling of the nasal septum, and the tumor was resected. These three tumors had similar histopathology, such as conspicuous fibrosclerotic changes with dense lymphoplasmacytic infiltration and occasional obliterative phlebitis. Immunohistochemistry indicated abundant IgG4-positive plasma cell infiltration and high ratios of IgG4-positive/IgG-positive plasma cells (>70%) in all three lesions. The diagnosis of multiple IgG4-related sclerosing lesions was made. The present case suggests that IgG4-related sclerosing lesion can occur in the maxillary sinus and nasal septum, and represents an extension of the spectrum of IgG4-related sclerosing disease.     

IgG4-related kidney disease

IgG4-related disease (IgG4-RD) is a recently recognized systemic immune-mediated disease that can affect nearly any organ or tissue. The most common manifestation in the kidney is IgG4-related tubulointerstitial nephritis (IgG4-TIN), which can present as renal insufficiency, renal mass lesions, or both. Histologically, IgG4-TIN is a plasma cell-rich interstitial inflammatory infiltrate with mononuclear cells, eosinophils, and increased IgG4+ plasma cells, along with expansile interstitial fibrosis that often has a “storiform” appearance. Tubular basement membrane immune complex deposits, best visualized on immunofluorescence staining, are present in most cases. IgG4-TIN usually shows a rapid response to steroid therapy. Glomeruli may be affected by IgG4-RD, usually in the form of membranous glomerulonephritis; other glomerular lesions have also been described. This review describes the different histopathologic patterns of renal involvement by IgG4-RD, with associated clinical, radiographic, and serologic features.     

A case of multiple immunoglobulin G4-related periarteritis: a tumorous lesion of the coronary artery and abdominal aortic aneurysm

Immunoglobulin G4 (IgG4)-related disease can occur in various organs, most of which are glandular or ductal tissues. Here, we report a case of multiple IgG4-related vascular lesions. A 63-year-old patient was found to have an abdominal aortic aneurysm and a tumorous lesion around the right coronary artery. The surgically resected aneurysmal wall and a tumorous lesion of the right coronary artery showed similar histologic features including diffuse lymphoplasmacytic infiltration, occasional eosinophils, and obliterative phlebitis. Immunohistochemically, numerous IgG4-positive plasma cells were evident within the lesions. The serum concentrations of IgG4 in the preoperative period was 456 mg/dL (reference range, <135), which decreased to 242 mg/dL 2 weeks after surgery. We made a diagnosis of multiple IgG4-related periarteritis manifesting as an abdominal aortic aneurysm and a tumorous nodule of the coronary artery. This case report suggested that IgG4-related disease can occur in the vascular system and manifest as an aneurysm or a periarterial mass lesion.     

IgG4-related periureteral fibrosis presenting as a unilateral ureteral mass

IgG4-related sclerosing disease is a rare disease characterized by fibrosis and lymphoplasmacytic infiltration in various organs. Here, we report a rare case of IgG4-related fibrosis that presented as a unilateral ureteral mass in a 39-year-old man who presented with abdominal pain. Left hydronephrosis and a mass measuring 3× 1.1 cm in the lower portion of the left ureter were found. As a ureteral malignancy could not be ruled out, the left ureter was resected partially. Pathologically, severe fibrosis and infiltration of plasma cells, lymphocytes, and eosinophils were found. No malignancy was found. Immunohistochemically, most of the plasma cells were IgG4-positive. The serum IgG4 level was also elevated (233 mg/dl). The histological characteristics were similar to those of retroperitoneal fibrosis, inflammatory pseudotumor, or idiopathic segmental ureteritis. It is important to consider IgG4-related sclerosing disease in the differential diagnosis of a unilateral ureteral mass.     

Characteristics and prognosis of IgG4-related periaortitis/periarteritis: A systematic literature review

ObjectiveImmunoglobulin G4 (IgG4)-related disease is a systemic chronic fibroinflammatory disease that can affect almost every organ of the body. IgG4-related periaortitis/periarteritis is a newly recognized subset of IgG4-related disease, and its characteristics and prognosis remain unclear. We investigated the clinical characteristics and prognosis of IgG4-related periaortitis/periarteritis.MethodsWe performed a systematic literature review of IgG4-related periaortitis/periarteritis. Additionally, we have summarized the characteristics and prognosis of IgG4-related coronary arteritis.ResultsWe investigated 248 patients with IgG4-related periaortitis/periarteritis. All studies reported the condition in elderly patients, and male predominance was observed. The infra-renal abdominal aorta and iliac arteries were the most commonly affected sites. Most reports showed the serum C-reactive protein elevation in this disease entity, in contrast to non-vascular IgG4-related disease. Based on radiological findings observed in 27 patients with IgG4-related coronary arteritis, vasculitic lesions were classified into 3 types: stenotic (67% of patients), aneurysmal (42%), and diffuse wall thickening type (92%). Serum IgG4 level, but not C-reactive protein level, was associated with the number of affected organs in IgG4-related coronary arteritis. Corticosteroid treatment with or without cardiac surgery or percutaneous coronary intervention was effective in most patients with IgG4-related coronary arteritis; however, 33% of patients showed an unfavorable clinical course including disease progression, relapse, or death. Pre-treatment stenosis and/or aneurysms were associated with progression of stenosis or aneurysm after corticosteroid treatment.ConclusionMost clinical characteristics were similar between the IgG4-related periaortitis/periarteritis and the non-vascular IgG4-related disease groups; however, serum C-reactive protein level elevation was observed only in the former. Although corticosteroid treatment was effective, this disease can be life-threatening secondary to myocardial infarction, aortic dissection, and aneurysmal rupture. Pre-treatment evaluation of stenosis or aneurysms is important for predicting progression of stenosis or aneurysm after corticosteroid treatment.     

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.     

Immunoglobulin G4-related disease: case report and literature review

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a rare and chronic progressive clinical entity, characterized by elevated serum IgG4 along with tissue infiltration by IgG4 + plasma cells. It is an immune-mediated fibro-inflammatory condition that can affect virtually any organ and tissue. IgG4-related lung disease (IgG4-RLD) occupies 14% of all IgG4-RD, with nonspecific symptoms and various abnormal radiographic patterns. Published data on IgG4-related hypertrophic pachymeningitis (IgG4-RHP), an increasingly recognized central nervous system manifestation of IgG4-RD, is also limited. Both lung and cranial dura involvement have not yet been reported until now. We further entail a review of the literature on the clinicopathologic features and differential diagnosis of this uncommon disease. We herein report an interesting case of a 70-year-old male patient admitted due to headache and fever. A magnetic resonance imaging (MRI) of the brain revealed extensive dural thickening with marked enhancement. Chest computed tomography (CT) scan showed nodular or mass-like consolidation and focal interstitial change. Thoracoscopic lung biopsy and lumbar puncture were conducted. After careful histopathological observation and consideration of alternative differential diagnoses, he was diagnosed with IgG4-related disease with lung and cranial dural involvement based upon significant elevation of serum and cerebrospinal fluid (CSF) IgG4 concentration. The patient was started on oral prednisolone 60 mg/day (1.0 mg/kg/day) for 14 days, and a tapering dose of 5 mg every 2 weeks followed by maintenance therapy at low dose for 3 months. His clinical manifestations, and serologic and imaging findings improved with steroid treatment. Currently, the patient remains well without disease progression. IgG4-RD should be considered as a differential when diagnosing other similar multisystemic lesions. Clinical examination, careful histological observation, and immunostaining for appropriate markers are essential in establishing the diagnosis. Clinicians should become familiar with this alternative differential diagnosis.

     

Pathological classification of hepatic inflammatory pseudotumor with respect to IgG4-related disease.

Recently, much attention has focused on IgG4-related disease, which is characterized by abundant IgG4-positive plasma cell infiltration and high serum IgG4 levels. IgG4-related disease sometimes manifests as tumorous lesions, and its relationship to inflammatory pseudotumor has been suggested. In this study, we examined clinicopathological features of a total of 16 cases of hepatic inflammatory pseudotumor (11 men and 5 women with an average age of 67 years) with respect to IgG4-related disease. The tumors could be pathologically classified into two types: fibrohistiocytic (10 cases) and lymphoplasmacytic (6 cases). Fibrohistiocytic inflammatory pseudotumors were characterized by xanthogranulomatous inflammation, multinucleated giant cells, and neutrophilic infiltration, and mostly occurred in the peripheral hepatic parenchyma as mass-forming lesions. In contrast, lymphoplasmacytic inflammatory pseudotumors showed diffuse lymphoplasmacytic infiltration and prominent eosinophilic infiltration, and were all found around the hepatic hilum. In addition, venous occlusion with little inflammation and cholangitis without periductal fibrosis were frequently observed in the fibrohistiocytic type, whereas obliterative phlebitis and cholangitis with periductal fibrosis were common features of the lymphoplasmacytic type. Interestingly, IgG4-positive plasma cells were significantly more numerous in the lymphoplasmacytic than fibrohistiocytic type. However, two of the fibrohistiocytic inflammatory pseudotumors had relatively many IgG4-positive plasma cells. In conclusion, hepatic inflammatory pseudotumor could be classified into two types based on clinicopathological characteristics. The lymphoplasmacytic type is unique, and could belong to the so-called IgG4-related diseases. In contrast, the fibrohistiocytic type might still be a heterogeneous group of disorders. This latter type seems pathologically different from IgG4-related disease, although cases with relatively abundant IgG4-positive plasma cells should be differentiated from IgG4-related disease with secondary histopathologic modifications.     

Occurrence of anaplastic large cell lymphoma following IgG4-related autoimmune pancreatitis and cholecystitis and diffuse large B-cell lymphoma

IgG4-related sclerosing disease is an established disease entity with characteristic clinicopathological features. Recently, the association between IgG4-related sclerosing disease and the risk of malignancies has been suggested. IgG4-related autoimmune pancreatitis with pancreatic cancer has been reported. Further, a few cases of extraocular malignant lymphoma in patients with IgG4-related sclerosing disease have also been documented. Herein, we describe the first documented case of anaplastic large cell lymphoma (ALCL) following IgG4-related autoimmune pancreatitis and cholecystitis and diffuse large B-cell lymphoma (DLBCL). A 61-year-old Japanese male, with a past history of DLBCL, was detected with swelling of the pancreas and tumorous lesions in the gallbladder. Histopathological study of the resected gallbladder specimen revealed diffuse lymphoplasmacytic infiltration with fibrosclerosis in the entire gallbladder wall. Eosinophilic infiltration and obliterative phlebitis were also noted. Immunohistochemically, many IgG4-positive plasma cells had infiltrated into the lesion, and the ratio of IgG4/IgG-positive plasma cells was 71.6%. Accordingly, a diagnosis of IgG4-related cholecystitis was made. Seven months later, he presented with a painful tumor in his left parotid gland. Histopathological study demonstrated diffuse or cohesive sheet-like proliferation of large-sized lymphoid cells with rich slightly eosinophilic cytoplasm and irregular-shaped large nuclei. These lymphoid cells were positive for CD30, CD4, and cytotoxic markers, but negative for CD3 and ALK. Therefore, a diagnosis of ALK-negative ALCL was made. It has been suggested that the incidence of malignant lymphoma may be high in patients with IgG4-related sclerosing disease, therefore, intense medical follow-up is important in patients with this disorder.     

Evaluation of Urine as a Clinical Specimen for Diagnosis of Hepatitis A

The present study pertains to the evaluation of urine as a specimen for detection of anti-hepatitis A virus (anti-HAV) antibodies. Immunoglobulin M (IgM), IgG, and IgA capture enzyme-linked immunosorbent assays for hepatitis A were performed on paired serum and urine specimens collected from hepatitis A patients (n = 92), healthy individuals (n = 100), non-A hepatitis patients (n = 70), and patients with nonhepatic diseases (n = 64, including 37 renal disease patients). Hepatitis A patients seropositive for anti-HAV IgM showed 95.65% uropositivity. No false-positive reactions were observed in control groups. The uropositivity of anti-HAV IgM persisted during the convalescent phase of the disease. Anti-HAV IgG uropositivity correlated well with corresponding seropositivity in all groups (P > 0.05 for each). No significant difference between the proportions of serum and urine positivity for anti-HAV IgA was noted (P > 0.05 for each). Using seroreactivity as a “gold standard,” the sensitivity and specificity for anti-HAV IgM, anti-HAV IgG, and anti-HAV IgA tests with urine as a specimen were found to be 95.65 and 100%, 97.76 and 76.47%, and 92.23 and 88.18%, respectively. Urine appears to be comparable to serum for diagnosis of recent and past infection with hepatitis A.     

Recent Concepts of Autoimmune Pancreatitis and IgG4-Related Disease

Recent studies suggested the existence of two subtypes of autoimmune pancreatitis (AIP): type 1 related with IgG4 (lymphoplasmacytic sclerosing pancreatitis; LPSP) and type 2 related with a granulocytic epithelial lesion (idiopathic duct-centric chronic pancreatitis; IDCP). Apart from type 2 AIP, the pathological features of type 1 AIP with increased serum IgG4/IgE levels, abundant infiltration of IgG4+ plasmacytes and lymphocytes, fibrosis, and steroid responsiveness are suggestive of abnormal immunity such as allergy or autoimmunity. Moreover, the patients with type 1 AIP often have extrapancreatic lesions such as sclerosing cholangitis, sclerosing sialadenitis, or retroperitoneal fibrosis showing similar pathological features. Based on these findings, many synonyms have been proposed for these conditions, such as “multifocal idiopathic fibrosclerosis”, “IgG4-related autoimmune disease”, “IgG4-related sclerosing disease”, “IgG4-related plasmacytic disease”, and “IgG4-related multiorgan lymphoproliferative syndrome”, all of which may refer to the same conditions. Therefore, the Japanese Research Committee for “Systemic IgG4-related Sclerosing Disease” proposed a disease concept and clinical diagnostic criteria based on the concept of multifocal fibrosclerosis in 2009, in which the term “IgG4-related disease” was appointed as a minimal consensus on these conditions. Although the significance of IgG4 in the development of “IgG4-related disease” remains unclear, we have proposed a hypothesis for the development of type 1 AIP, one of the IgG4-related disease. The concept and diagnostic criteria of “IgG4-related disease” will be changed in accordance with future studies.     

Hepatobiliary manifestations of IgG4-related disease

IgG4-related disease involving the liver and biliary tree exhibits variable morphological changes. The most common manifestation is sclerosing cholangitis characterized by pipe stem-like fibrosis of the wall and extensive inflammation. IgG4-related sclerosing cholangitis sometimes exhibits pseudo-tumourous exuberance around the hilar bile duct (inflammatory pseudotumour), radiological features of which are reminiscent of hilar cholangiocarcinoma. Another minor manifestation is IgG4-related chronic active hepatitis. Consistent with other manifestations of IgG4-related disease, pathological features include diffuse lymphoplasmacytic infiltration, irregular fibrosis typically in a storiform pattern, and moderate tissue eosinophilia. On immunostaining, not only the absolute number of IgG4-positive plasma cells but also the IgG4/IgG-positive ratio is dramatically increased. Pathologists need to be aware of this condition, as the diagnosis requires a multi-disciplinary approach, in which pathological examination has a critical role.     

Organ Correlation in IgG4-Related Diseases

IgG4-related disease (IgG4-RD) is a potentially multiorgan disorder. In this study, clinical and serological features from 132 IgG4-RD patients were compared about organ correlations. Underlying pathologies comprised autoimmune pancreatitis (AIP) in 85 cases, IgG4-related sclerosing cholangitis (IgG4-SC) in 12, IgG4-related sialadenitis (IgG4-SIA) in 56, IgG4-related dacryoadenitis (IgG4-DAC) in 38, IgG4-related lymphadenopathy (IgG4-LYM) in 20, IgG4-related retroperitoneal fibrosis (IgG4-RF) in 19, IgG4-related kidney disease (IgG4-KD) in 6, IgG4-related pseudotumor (IgG4-PT) in 3. Sixty-five patients (49%) had multiple IgG4-RD (two affected organs in 36 patients, three in 19, four in 8, five in 1, and six in 1). Serum IgG4 levels were significantly higher with multiple lesions than with a single lesion (P<0.001). The proportion of association with other IgG4-RD was 42% in AIP, the lowest of all IgG4-RDs. Serum IgG4 level was lower in AIP than in other IgG4-RDs. Frequently associated IgG4-RDs were SIA (25%) and DAC (12%) for AIP; AIP (75%) for IgG4-SC; DAC (57%), AIP (38%) and LYM (27%) for IgG4-SIA; AIP (26%) and LYM (26%) for IgG4-DAC; SIA (75%), DAC (50%) and AIP (45%) for IgG4-LYM; SIA (58%), AIP (42%) and LYM (32%) for IgG4-RF; AIP (100%) and SIA (67%) for IgG4-KID; and DAC (67%) and SIA (67%) for IgG4-PT. Most associated IgG4-RD lesions were diagnosed simultaneously, but IgG4-SIA and IgG4-DAC were sometimes identified before other lesions. About half of IgG4-RD patients had multiple IgG4-RD lesions, and some associations were seen between specific organs.

Graphical Abstract

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Suppression of pulmonary injury in experimental 'Goodpasture's syndrome' by deoxyspergualin (DSP).

DSP is a potent immunosuppressive drug which can prevent allograft rejection and suppress acute rejection episodes. In this study, the ability of DSP to suppress pulmonary injury in experimental Goodpasture's syndrome was investigated. Passive accelerated anti-glomerular basement membrane (GBM) disease was induced in rats by priming with rabbit IgG, followed 5 days later by injection of rabbit anti-GBM serum (day 0). Groups of five animals were treated with DSP (5 mg/kg intraperitoneally per day) or saline (untreated) from day 0 until being killed on days 1, 7, 14 or 21. At day 1, both DSP-treated and untreated animals exhibited similar pulmonary haemorrhage, oedema, and prominent perivascular leucocyte infiltration. Untreated animals subsequently developed severe widespread pulmonary damage including granulomatous lesions and extensive fibrosis, which correlated with infiltration of macrophages and immune-activated (IL-2R+) mononuclear cells (P < 0.01). Tumour necrosis factor-alpha (TNF-alpha), a known mediator of acute lung damage, was produced by pulmonary mononuclear cells throughout the experimental course. In contrast, DSP treatment resolved pulmonary haemorrhage, prevented the appearance of granulomatous lesions, and resulted in a histologically normal lung structure by day 21. This improvement was associated with a marked suppression of macrophage infiltration (P < 0.001 versus untreated), accumulation of immune activated (IL-2R+) mononuclear cells (P < 0.01 versus untreated), and TNF-alpha production (P < 0.05 versus untreated). DSP treatment also suppressed the deposition of rat anti-rabbit IgG immunoglobulin and C3 along the alveolar basement membrane (P < 0.05 versus untreated). In conclusion, DSP suppressed pulmonary injury in accelerated anti-GBM disease by acting on the local cellular immune response and the systemic humoral immune response. Further studies are warranted to determine whether this could be a useful drug for the treatment of Goodpasture's syndrome in humans.     

A case of IgG4-related sclerosing mesenteritis

IgG4-related disease has been recognized as a systemic syndrome characterized by mass-forming lesions with lymphoplasmacytic infiltration and sclerosis. This disease has been identified in various sites, including the pancreas, retroperitoneum, lung, head, and neck. Herein we report a case of IgG4-related sclerosing mesenteritis. An 82-year-old woman was admitted to our hospital due to persistent abdominal pain. Abdominal computed tomography demonstrated a solitary mass with a maximal diameter of 11.7 cm in mesentrium of the small intestine. On her laboratory examination, only C-reactive protein level was elevated. Although the pre-operative diagnosis was indefinite, she underwent ileocecectomy. Grossly, an elastic soft mass with foci of hemorrhage was seen in the mesentrium. Microscopically, the lesion was composed of fibroblastic or myofibroblastic spindle cells with abundant stromal fibrosis and inflammatory infiltrate, such as lymphocytes and plasma cells accompanied by lymphoid follicles with a germinal center. Obstructive phlebitis was observed. Immunohistochemically, numerous IgG4-positive plasma cells were observed, and the IgG4/IgG ratio was 75.9%. The serum level of IgG4 examined at post-operation was high. These findings suggested that this lesion was consistent with IgG4-related sclerosing mesenteritis.     

Immunohistochemistry of IgG4 can help subclassify Hashimoto's autoimmune thyroiditis

IgG4-related sclerosing disease has been recently recognized as a systemic disease entity characterized by an elevated serum IgG4 level, sclerosing fibrosis and diffuse lymphoplasmacytic infiltration by many IgG4-positive plasma cells. Similar histopathological features have often been noted in the fibrous variant of Hashimoto's autoimmune thyroiditis, but thyroid gland involvement has been only briefly mentioned with regard to IgG4, and no immunohistochemistry for IgG4 has been reported in Hashimoto's autoimmune thyroiditis. Herein, the purpose of the present study was to investigate the infiltration of IgG- and IgG4-positive plasma cells on immunohistochemistry for a panel of thyroiditis samples (Hashimoto's autoimmune thyroiditis, n = 13; subacute thyroiditis, n = 2; lymphocytic thyroiditis, n = 2). Cases of Hashimoto's thyroiditis could be classified into two groups based on immunostaining of IgG4: IgG4 thyroiditis (IgG4-related, IgG4-positive plasma cell-rich thyroiditis) and non-IgG4 thyroiditis (non-IgG4-related, IgG4-positive plasma cell-poor thyroiditis). IgG4 thyroiditis presents with severe lymphoplasmacytic infiltration, dense fibrosis, marked follicular cell degeneration, oxyphilic change and lymphoid follicle formation, while non-IgG4 thyroiditis presents with relatively mild or absent histopathological characteristics. In conclusion, immunostaining of IgG4 can help subclassify Hashimoto's thyroiditis; and IgG4 thyroiditis may have a close relationship with IgG4-related sclerosing disease.     

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.     

The levels of IL-1β and soluble IL-1 receptors in patients with IgG4-related periaortitis/periarteritis

PurposeIgG4-related disease (IgG4-RD) is a chronic fibrotic inflammatory and an immune-mediated disease characterized by high serum IgG4 concentration and IgG4-bearing plasma cell infiltration in affected organs. IgG4-related periaortitis/periarteritis is a recently identified disease entity in IgG4-RD that affects the cardiovascular system, and its pathogenesis and characteristics remain unclear.The inflammatory cytokine IL-1β is involved in a variety of cellular activities including inflammation, fibrosis, and angiogenesis. The present study compared the levels of the inflammatory cytokine IL-1β and two soluble IL-1 receptors, IL-1R1 and IL-1R2, between IgG4-RD patients with and without IgG4-related periaortitis/periarteritis.MethodsThe patients with IgG4-related periaortitis/periarteritis (n ?= ?38), those without (n ?= ?66) and healthy (n ?= ?33) were recruited to measure cytokines of IL-1β and soluble receptors (sIL-1R1 and sIL-1R2) in sera by ELISA assay.ResultsSerum IgG4 was significantly higher in patients with periaortitis/periarteritis compared to non-periaortitis/periarteritis (p ?= ?0.0074), while serum IL-1β was significantly lower in patients with periaortitis/periarteritis (p ?= ?0.00037).The three groups did not show significant difference in sIL1-R1, while sIL-1R2 in the periaortitis/periarteritis and healthy group was higher than in the group without periaortitis/periarteritis (p ?= ?0.00001).ConclusionsThe characteristic changes in IL-1β, sIL-1R1, and sIL-1R2 levels in IgG4-RD patients with and without IgG4-related periaortitis/periarteritis may indicate an active phase of the inflammatory process in these diseases.     

Idiopathic vs. secondary retroperitoneal fibrosis: a clinicopathological study of 12 cases, with emphasis to possible relationship to IgG4-related disease

Retroperitoneal fibrosis (RF) is a rare disease characterized by inflammation and fibrosis of retroperitoneal soft tissues. It is classified into two types: idiopathic (iRF) and secondary (sRF). The aim of the study was to investigate the relationship between iRF and IgG4-related disease (IgG4-RD) and to eventually extend the clinicopathological features of this condition by analysis of the sample comprising six iRF and six sRF patients. The iRF patients included four males and two females, aged 12–62 years (median 55 years). Two lesions were periaortic, one was periureteral, and three cases showed both periaortic and periureteral localization. Two patients had increased serum levels of IgG4. None of the patients developed any manifestation of IgG4-RD during the follow-up period ranging for 15–133 months (median 43 months). Microscopically, in two iRF cases, fibrosis was highly cellular encircling the vessels, nerves, and paraganglia. Phlebitis was found in all cases and being obliterative in four. Lymphocytic inflammation with formation of follicles and plasma cell infiltration were scored as severe in five iRF cases. The numbers of IgG-positive plasma cells ranged 0–373 per 1 HPF (high power field; median 132) and of IgG4-positive plasma cells 0–238 per 1 HPF (median 91). The IgG4/IgG ratio values ranged 0.38–0.74 (median 0.68). Two of the iRF cases were diagnosed as definite and three cases as probable IgG4-RD. To the contrary, none of the sRF cases met the diagnostic criteria for either definite, probable, or possible IgG4-related disease. Our results indicate that a substantial portion of iRF cases, including some of very rare pediatric cases, is a manifestation of IgG4-RD.     

Concomitant occurrence of IgG4-related pleuritis and periaortitis: a case report with review of the literature

IgG4-related sclerosing disease is an established disease entity with characteristic clinicopathological features. Some recent reports have demonstrated that this disease can occur in the respiratory system including the pleura. Herein, we describe the first documented case of concomitant occurrence of IgG4-related pleuritis and periaortitis. A 71-year-old Japanese female with a history of essential thrombocythemia presented with persistent cough and difficulty in breathing. Computed tomography demonstrated thickening of the right parietal pleura, pericardium, and periaortic tissue and pleural and cardiac effusions. Histopathological study of the surgical biopsy specimen of the parietal pleura revealed marked fibrous thickening with lymphoplasmacytic infiltration. Phlebitis was noted, however, only a few eosinophils had infiltrated. Immunohistochemical study revealed abundant IgG4-positive plasma cell infiltration and high ratio of IgG4-/IgG-positive plasma cells (84%). Therefore, a diagnosis of IgG4-related pleuritis was made with consideration of the elevated serum IgG4 level (684 mg/dL). Recently, the spectrum of IgG4-related sclerosing disease has expanded, and this disease can occur in the pleura, pericardium, and periaortic tissue. Although histopathological analysis of the pericardium and periaortic tissue was not performed in the present case, it was suspected that thickening of the pericardium and periaortic tissue was clinically due to IgG4-related sclerosing disease. Our clinicopathological analyses of IgG4-related pleuritis and pericarditis reveal that this disease can present as dyspnea and pleural and pericardial effusion as seen in the present case, therefore, it is important to recognize that IgG4-related sclerosing disease can occur in these organs for accurate diagnosis and treatment.