Kyotaro Ohno

Clinicopathologic analysis of IgG4-related skin disease

IgG4-related disease is a recently recognized systemic syndrome characterized by mass-forming lesions with lymphoplasmacytic infiltration, increase in the number of IgG4+ cells in affected tissues and elevation of serum IgG4 levels. In 2009, we were the first to report skin lesions in patients with IgG4-related disease, but no large case series has been reported and clinicopathological findings remain unclear. To clarify these features, we herein report 10 patients (9 men and 1 woman; median age, 64 years; age range, 46–81 years) with IgG4-related skin disease. All patients had erythematous and itchy plaques or subcutaneous nodules on the skin of the head and neck, particularly in the periauricular, cheek, and mandible regions, except for one patient, whose forearm and waist skin were affected. In addition, eight patients had extracutaneous lesions: these were found on the lymph nodes in six patients, the lacrimal glands in three patients, the parotid glands in three patients, and the kidney in one patient. Histologically examined extracutaneous lesions were consistent with IgG4-related disease; five of six lymph node lesions showed progressively transformed germinal centers-type IgG4-related lymphadenopathy. Cases of IgG4-related skin disease were classified into two histological patterns: those exhibiting a nodular dermatitis pattern and those with a subcutaneous nodule pattern. The infiltrate was rich in plasma cells, small lymphocytes, and eosinophils; the majority of the plasma cells were IgG4+. The IgG4+ cell count was 49–396 per high-power field (mean±s.d., 172±129), with an IgG4+/IgG+ cell ratio ranging from 62 to 92%. Serum IgG4 levels were elevated in all examined patients. In conclusion, patients with IgG4-related skin disease had uniform clinicopathology. Lesions were frequently present on the skin of the periauricular, cheek, and mandible regions, and were frequently accompanied by IgG4-related lymphadenopathy.

T helper 2 and regulatory T-cell cytokine production by mast cells: a key factor in the pathogenesis of IgG4-related disease

IgG4-related disease is a systemic disorder with unique clinicopathological features and uncertain etiological features and is frequently related to allergic disease. T helper 2 and regulatory T-cell cytokines have been reported to be upregulated in the affected tissues; thus, the production of these cytokines by T helper 2 and regulatory T cells has been suggested as an important factor in the pathogenesis of IgG4-related disease. However, it is not yet clear which cells produce these cytokines in IgG4-related disease, and some aspects of the disorder cannot be completely explained by T-cell-related processes. To address this, we analyzed paraffin-embedded sections of tissues from nine cases of IgG4-related submandibular gland disease, five cases of submandibular sialolithiasis, and six cases of normal submandibular gland in order to identify potential key players in the pathogenesis of IgG4-related disease. Real-time polymerase chain reaction analysis confirmed the significant upregulation of interleukin (IL)4, IL10, and transforming growth factor beta 1 (TGFβ1) in IgG4-related disease. Interestingly, immunohistochemical studies indicated the presence of mast cells expressing these cytokines in diseased tissues. In addition, dual immunofluorescence assays identified cells that were double-positive for each cytokine and for KIT, which is expressed by mast cells. In contrast, the distribution of T cells did not correlate with cytokine distribution in affected tissues. We also found that the mast cells were strongly positive for IgE. This observation supports the hypothesis that mast cells are involved in IgG4-related disease, as mast cells are known to be closely related to allergic reactions and are activated in the presence of elevated non-specific IgE levels. In conclusion, our results indicate that mast cells produce T helper 2 and regulatory T-cell cytokines in tissues affected by IgG4-related disease and possibly have an important role in disease pathogenesis.

IgG4-related disease involving the sclera

Abstract A 49-year-old female patient previously treated for scleritis and uveitis-induced cataract in the right eye presented with a subretinal white lesion in the same eye. With a preliminary diagnosis of choroidal tumor, enucleation of the eyeball was performed in accordance with the patient’s request. Histologic and immunohistologic examinations were consistent with immunoglobulin G4-related disease. The case demonstrates that it is important to consider IgG4-related disease in the differential diagnosis of an intraocular tumor.

Cutaneous multicentric Castleman's disease mimicking IgG4-related disease.

Castlemans 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 Castlemans 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 Castlemans 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 (1490 mg/dl; normal range: 4.8-105 mg/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 Castlemans 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.

Interleukin 13-positive mast cells are increased in immunoglobulin G4-related sialadenitis

Interleukin (IL)-13 is a T helper 2 (Th2) cytokine that plays important roles in the pathogenesis of asthma. IL-13 induces hypersensitivity of the airways, increased mucous production, elevated serum immunoglobulin (Ig) E levels, and increased numbers of eosinophils. Many patients with IgG4-related disease have allergic backgrounds and show elevated serum IgE levels and an increase in the number of eosinophils. Upregulation of Th2/regulatory T (Treg) cytokines, including IL-13, has been detected in affected tissues of patients with IgG4-related disease. We previously reported that mast cells might be responsible for the production of the Th2/Treg cytokines IL-4, IL-10, and transforming growth factor (TGF)-β1 in IgG4-related disease. In this study, immunohistochemical analysis showed increased numbers of IL-13-positive mast cells in IgG4-related disease, which suggests that mast cells also produce IL-13 and contribute to elevation of serum IgE levels and eosinophil infiltration in IgG4-related disease.

A subset of ocular adnexal marginal zone lymphomas may arise in association with IgG4-related disease

We previously suggested a relationship between ocular immunoglobulin (Ig)G4-related disease (IgG4-RD) and marginal zone lymphomas (MZLs). However, the cytokine background associated with these disorders and whether it differs between ocular adnexal MZLs with (IgG4-associated MZL) and without (IgG4-negative MZL) numerous IgG4+ plasma cells are unknown. In this study, we identified the mRNA expression pattern of Th2 and regulatory T-cell (Treg) cytokines in IgG4-RD and in IgG4-associated MZL and IgG4-negative MZL using real-time polymerase chain reaction analysis. Ocular IgG4-RD and IgG4-associated MZL exhibited significantly higher expression ratios of interleukin (IL)-4/β-actin, IL-10/β-actin, IL-13/β-actin, transforming growth factor (TGF) β1/β-actin, and FOXP3/β-actin than did IgG4-negative MZL (p < 0.05). This finding further supports our prior observations that a significant subset of ocular MZLs arises in the setting of IgG4-RD. Furthermore, the presence of a different inflammatory background in IgG4-negative MZLs suggests that IgG4-associated MZLs may have a different pathogenesis.

Epstein-Barr virus-infected cells in IgG4-related lymphadenopathy with comparison with extranodal IgG4-related disease.

IgG4-related lymphadenopathy with increased numbers of Epstein-Barr virus (EBV)-infected cells has been reported but not fully described. We analyzed 31 cases of IgG4-related lymphadenopathy and 24 cases of extranodal IgG4-related diseases for their possible relationship with EBV. Other types of reactive lymph nodes (22) and angioimmunoblastic T-cell lymphoma (AITL) (10) were also studied for comparison. EBV-encoded RNA (EBER) in situ hybridization revealed EBER+ cells in 18 of 31 cases (58%) of IgG4-related lymphadenopathy. Increased EBER+ cells were found in only 4 of 22 (18.1%) non–IgG4-related reactive lymphoid hyperplasia in patients of a similar age (P=0.002) and in only 5 of 24 (21%) extranodal IgG4-related biopsies (P=0.006). Interestingly, all patients with EBER+ progressively transformed germinal center–type IgG4-related lymphadenopathy had systemic lymphadenopathy and/or extranodal involvement. AITL also is associated with EBV, and IgG4-related lymphadenopathy sometimes mimics the morphology of AITL; however, the number of IgG4+ cells in AITL was significantly less than that in IgG4-related lymphadenopathy (P<0.001). Increased numbers of regulatory T cells are seen in IgG4-related disease; however, there was not a significant difference between the EBER+ and EBER− cases. In conclusion, the presence of increased numbers of EBV-infected cells in IgG4-related lymphadenopathy, compared with other reactive lymphadenopathy or extranodal IgG4-related disease, suggests that there may be a relationship at least between nodal IgG4-related disease and EBV. It is important to avoid overdiagnosing these cases as malignant lymphomas or EBV-related lymphoproliferative disorders.

Regulatory T-cell infiltration in tongue squamous cell carcinoma

Abstract Conclusion: In tongue squamous cell carcinoma (SCC), high levels of regulatory T-cell (Treg) infiltration in tumor nests are observed in the cases with poor prognosis. Objectives: The role of Tregs in head and neck cancers remains unclear. The aim of this study was to observe the distribution of Tregs in different stages of tongue SCC and estimate the effects on prognosis. Methods: Thirty-four cases with tongue SCC were examined immunohistochemically for CD4, CD8, and Forkhead box P3 (Foxp3). Immunoreactive cells were counted in cancer stroma and nest regions, and relationships between cell numbers and disease-free survival rates were analyzed. Results: In the 34 cases, univariate analysis for disease-free survival indicated high-level infiltration of Tregs (CD4+Foxp3+) into both cancer nests and stroma and presence of helper T (CD4+Foxp3–) cells in cancer stroma as potential predictors of significantly worse prognosis. In early-stage cases (stage I/II), high-level infiltration of Tregs in cancer nests correlated significantly with poor disease-free survival rate. Multivariate analysis for disease-free survival found no independent variables.

Anti–high mobility group box 1 monoclonal antibody improves ischemia/reperfusion injury and mode of liver regeneration after partial hepatectomy

BACKGROUND The purpose of this study is to determine the effects of anti-high mobility group box 1 (HMGB1) monoclonal antibody (mAb) on ischemia/reperfusion injury (IRI) and the mode of liver regeneration. METHODS Rats underwent 70% hepatectomy with IRI caused by clamping the hepatoduodenal ligament for 20 minutes, followed by the administration of anti-HMGB1 mAb immediately before declamping the hepatoduodenal ligament. Five animals were used for each time point. We then evaluated IRI, regeneration parameters and the status of HMGB1 in remnant livers. RESULTS The anti-HMGB1 mAb significantly ameliorated the degree of IRI in the remnant livers in association with the downregulation of HMGB1 protein. The ratio of Ki67-positive hepatocytes at 48 hours after 70% hepatectomy was significantly improved. Mean hepatocyte size was significantly reduced and cyclin-dependent kinase inhibitor 1 expression was significantly attenuated. CONCLUSIONS Anti-HMGB1 mAb ameliorated IRI and improved the mode of liver regeneration after IRI followed by 70% hepatectomy in rats.

Regulatory T cells function at the early stage of tumor progression in a mouse model of tongue squamous cell carcinoma.

The objective of this study was to observe the distribution of regulatory T cells (Tregs) in the development of tongue squamous cell carcinoma (SCC) and to determine the role of Tregs in the progression of tongue SCC. A mouse model of 4-nitroquinoline-1-oxide (4NQO)-induced-tongue SCC was established. The expression of Forkhead box P3 (Foxp3), interleukin 10, transforming growth factor-β, chemokine CC motif ligands 17, 20, and CC chemokine receptor 4 was determined using real-time quantitative polymerase chain reaction. Foxp3 expression was also analyzed using immunohistochemistry. The results were compared with those of control mice and of 4NQO-treated mice treated with a cyclooxygenase-2 (COX-2) inhibitor. Well to moderately differentiated tongue SCC was induced in all of the experimental mice. The amount of Tregs of the experimental mice was over 10 times as much as control mice at the early stage of tumor progression. COX-2 inhibitor did not prevent the progression of tongue SCC and did not reduce the total amount of Tregs. Tregs function at the early stage of the development of tongue SCC, and it may be effective to suppress Tregs at the early stage of tumor progression for the treatment and/or prevention of tongue SCC.