IgG4-related Cases Research Articles

Inflammatory abdominal aortic aneurysms: place of Ig G4related diseases

Aim. Inflammatory abdominal aortic aneurysm may be one of the manifestations of Ig G4-related disease. This study analyzes the clinical manifestations of Ig G4related inflammatory abdominal aortic aneurysm. Material and methods. We examined twenty patients with abdominal aortic aneurysm (AAA). The clinical performance of the disease, the results of laboratory and pathomorphological studies were studied. In 8 cases, Ig G4-related inflammatory AAA criteria were identified. Results. Compared to atherosclerotic AAA, Ig G4-related cases were characterized by a less frequent presence of abdomen or back pain. The concentration of IgG4 in serum in Ig G4-related cases was significantly increased. Patients with Ig G4-related inflammatory AAA often had a history of allergic reactions to drugs, autoimmune diseases, a high concentration of Ig E and a high titer of antinuclear antibodies in blood serum. According to a histological study of intraoperative biopsy samples, Ig G4-related cases were characterized by thickening of adventitia and numerous infiltrates with Ig G4-positive plasma cells. Conclusion. The presence of Ig G4-related disease is diagnosed in the presence of irregular fibrous tissue proliferation with Ig G4 plasma cell infiltrates and with an increase in the concentration of Ig G4 in blood serum. Ig G4-related inflammatory AAA has clinical specifics in comparison with atherosclerotic aneurysm.

A small subgroup of Hashimoto's thyroiditis is associated with IgG4-related disease.

IgG4-related disease is a newly identified syndrome characterized by high serum IgG4 levels and increased IgG4-positive plasma cells in involved organs. The incidence of IgG4-related thyroiditis in the Caucasian population of Europe is unknown. We investigated formalin-fixed thyroid gland samples of 216 patients (191 Hashimoto's thyroiditis, 5 Riedel's thyroiditis, and 20 goiters, as controls), morphologically, and immunohistochemically. Cases were divided into two groups: IgG4-related Hashimoto's thyroiditis (24 cases) together with Riedel thyroiditis (1 case) and 171 non-IgG4-related thyroiditis. Compared to the non-IgG4-related cases, IgG4-related thyroiditis showed a higher IgG4/IgG ratio (0.6 vs. 0.1, p < 0.0001), a higher median IgG4 count (45.2 vs. 6.2, p < 0.0001), an association with younger age (42.1 vs. 48.1 years, p = 0.036), and a lower female-to-male ratio (11:1 vs. 17.5:1). Fibrous variant of Hashimoto's thyroiditis was diagnosed in 23 of the 24 IgG4-related cases (96 %) and in 13 of 167 (18 %, p > 0.001) non-IgG4-related cases. The single case of IgG4-related Riedel's thyroiditis also showed a higher median IgG4 plasma cell count (56.3 vs. 14.3) and a higher IgG4/IgG ratio (0.5 vs. 0.2) than the four cases of non-IgG4-related Riedel's thyroiditis. Our data suggests the incidence of IgG4-related disease (IgG4-RD) of the thyroid gland in Europe is considerably lower than that observed in other studies. A significant elevation of IgG4-positive plasma cells was only found in a small group of Hashimoto's thyroiditis and then accompanied by intense fibrosis, indicating an association with IgG4-RD. Morphologically, IgG4-RD of the thyroid gland differs from that in other organ systems, exhibiting a dense fibrosis without intense eosinophilia or obliterative phlebitis.

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.

Retroperitoneal Fibrosis: A Clinicopathologic Study With Respect to Immunoglobulin G4

The possible involvement of immunoglobulin G4 (IgG4) in the pathogenesis of idiopathic sclerosing lesions has been suggested. In this study, a clinicopathologic analysis was performed to reveal characteristics of retroperitoneal fibrosis relating to IgG4. The study involved 17 patients with retroperitoneal fibrosis. Immunohistochemistry revealed numerous IgG4-positive plasma cell infiltrates in 10 cases (IgG4-related), but only a few positive cells in 7 cases (non-IgG4-related). All patients with IgG4-related retroperitoneal fibrosis were male, whereas all except 1 with unrelated lesions were female. Histologically, eosinophilic infiltration (>5 cells per high-power field) and obliterative phlebitis were commonly observed in IgG4-related lesions. Serologically, serum IgG and IgG4 concentrations were significantly higher in the IgG4-related cases, with the IgG4 concentrations all over 135 mg/dL (the upper limit of the normal range). Steroid therapy was performed in 13 cases, and was effective irrespective of IgG4. Three patients had recurrence during the follow up. Five of 10 IgG4-related cases had sclerosing lesions at other sites. The only tests that reliably distinguish the 2 groups were serum IgG4 levels or IgG4/IgG ratio in the plasma cells in a tissue biopsy. The only major clinical difference was the striking male predominance in IgG4-related cases. In conclusion, this study revealed that retroperitoneal fibrosis could be classified as IgG4-related or not. This distinction seems important to help better characterize the biology/pathogenesis of both groups and better predict the possibility of other IgG4-related processes at other anatomic sites.

A new clinicopathological entity of IgG4-related inflammatory abdominal aortic aneurysm

Recently, the relationship between immunoglobulin (Ig)G4 and idiopathic sclerosing lesions has attracted much attention. IgG4-related disease was first described with regard to the pancreas (autoimmune pancreatitis), and has been expanded to various organ systems. We previously reported that inflammatory abdominal aortic aneurysm (IAAA) could be one of the manifestations of IgG4-related disease. In this study, we tried to elucidate the clinical characteristics of IgG4-related IAAA. This study consisted of 23 cases of IAAA and 40 cases of atherosclerotic abdominal aortic aneurysm (AAA). Clinical presentation, laboratory findings, and pathological features were examined. Aneurysms of 13 cases histologically corresponded to IgG4-related IAAA. Those cases accounted for 5% of all surgical AAAs, and 57% of IAAAs. Compared to non-IgG4-related IAAA, IgG4-related cases were characterized by less frequent association with abdominal or back pain. Serum IgG4 concentrations were significantly elevated in IgG4-related cases. Interestingly, patients with IgG4-related IAAA frequently showed an allergic constitution, such as drug allergy, autoimmune diseases, high serum IgE concentrations, and a high titer of antinuclear antibody. Pathologically, IgG4-related cases were characterized by more significant thickening of the adventitia and more numerous IgG4-positive plasma cell infiltrations. Three non-IgG4-related cases showed aneurysmal rupture at the time of first presentation, whereas no IgG4-related cases showed rupture. Recognizing a new disease entity of IgG4-related IAAA seems important because this was clinically and pathologically different from conventional aAAA and non-IgG4-related IAAA.

Inflammatory Abdominal Aortic Aneurysm: Close Relationship to IgG4-related Periaortitis

Inflammatory abdominal aortic aneurysm (AAA) is a member of a family of disorders referred to as "chronic periaortitis" together with retroperitoneal fibrosis. Retroperitoneal fibrosis is included in IgG4-related disease, which is characterized by numerous infiltrating IgG4-positive plasma cells and high serum IgG4 concentrations. However, the relationship between IgG4-related disease and inflammatory AAA has not been documented. In this study, we examined the clinicopathologic characteristics of inflammatory (10 cases) and atherosclerotic (22 cases) AAAs, based on the hypothesis that inflammatory AAA might be related to IgG4-related disease. Cases of inflammatory AAA could be classified into 2 groups based on immunostaining of IgG4. Four patients showed diffuse infiltration of abundant IgG4-positive plasma cells (IgG4-related cases), whereas the remaining 6 cases of inflammatory AAA and all cases of atherosclerotic AAA had only a few IgG4-positive plasma cells (non-IgG4-related cases). IgG4-related inflammatory AAA was pathologically characterized by the frequent infiltration of eosinophils, lymph follicle formation, perineural inflammatory extension, and inconspicuous infiltration of neutrophils compared with non-IgG4-related inflammatory AAA. Obliterative phlebitis, which is venous occlusion with inflammatory cell infiltration, is observed in all IgG4-related cases. In addition, serum IgG4 concentrations were significantly higher in IgG4-related inflammatory AAA (109 to 559 mg/dL, normal range: 4 to 110 mg/dL) than non-IgG4-related inflammatory AAA (32 to 59 mg/dL) and all atherosclerotic AAA (12 to 83 mg/dL). In conclusion, inflammatory AAAs might be classified into 2 groups: IgG4-related or nonrelated. The former might be one of the IgG4-related diseases, and could be included in IgG4-related periaortitis together with retroperitoneal fibrosis.