Haruka Iwao

Cutoff Values of Serum IgG4 and Histopathological IgG4+ Plasma Cells for Diagnosis of Patients with IgG4-Related Disease.

IgG4-related disease is a new disease classification established in Japan in the 21st century. Patients with IgG4-related disease display hyper-IgG4-gammaglobulinemia, massive infiltration of IgG4+ plasma cells into tissue, and good response to glucocorticoids. Since IgG4 overexpression is also observed in other disorders, it is necessary to diagnose IgG4-related disease carefully and correctly. We therefore sought to determine cutoff values for serum IgG4 and IgG4/IgG and for IgG4+/IgG+ plasma cells in tissue diagnostic of IgG4-related disease. Patients and Methods. We retrospectively analyzed serum IgG4 concentrations and IgG4/IgG ratio and IgG4+/IgG+ plasma cell ratio in tissues of 132 patients with IgG4-related disease and 48 patients with other disorders. Result. Serum IgG4 >135  mg/dl demonstrated a sensitivity of 97.0% and a specificity of 79.6% in diagnosing IgG4-related disease, and serum IgG4/IgG ratios >8% had a sensitivity and specificity of 95.5% and 87.5%, respectively. IgG4+cell/IgG+ cell ratio in tissues >40% had a sensitivity and specificity of 94.4% and 85.7%, respectively. However, the number of IgG4+ cells was reduced in severely fibrotic parts of tissues. Conclusion. Although a recent unanimous consensus of all relevant researchers in Japan recently established the diagnostic criteria for IgG4-related disease, findings such as ours indicate that further discussion is needed.

Multicentric Castleman's disease with abundant IgG4-positive cells: a clinical and pathological analysis of six cases

Background Differentiation between multicentric Castlemans disease and systemic immunoglobulin (Ig) G4-related lymphadenopathy is sometimes difficult. It has been suggested that measurement of the IgG4-/IgG-positive cell ratio is useful for the differential diagnosis of the two diseases. However, the authors present a detailed report of six patients with multicentric Castlemans disease with abundant IgG4-positive cells (IgG4-/IgG-positive cell ratio, >40%). Results In the present series, the patients showed systemic lymphadenopathy, polyclonal hypergammaglobulinaemia and elevated serum interleukin-6 (IL-6) and C-reactive protein levels. Further, anaemia, hypoalbuminaemia, hypocholesterolaemia and thrombocytosis were observed. These findings were consistent with those of multicentric Castlemans disease. Although five patients showed elevated serum IgG4 levels, only two patients showed an increased serum IgG4/IgG ratio. However, the two patients showed highly elevated serum IgG4 levels, but the serum IgG4/IgG ratios were, although increased, not very high. Also, a patient with increased serum IgG4/IgG ratio showed a good response to antihuman IL-6 receptor monoclonal antibody (tocilizumab). Histologically, the germinal centres were mostly small and regressive, and frequently penetrated by hyalinised blood vessels, and there was no eosinophil infiltration. These findings were different from those of IgG4-related lymphadenopathy. Conclusions The authors conclude that multicentric Castlemans disease sometimes occurs with abundant IgG4-positive cells and elevated serum IgG4 levels. Therefore, the two diseases cannot be differentially diagnosed by immunohistochemical staining alone. Laboratory findings, especially IL-6 level, C-reactive protein level and platelet count, are important for the differential diagnosis of the two diseases.

Deficient leptin signaling ameliorates systemic lupus erythematosus lesions in MRL/Mp-Fas lpr mice.

Leptin is secreted by adipocytes, the placenta, and the stomach. It not only controls appetite through leptin receptors in the hypothalamus, it also regulates immunity. In the current study, we produced leptin-deficient MRL/Mp-Faslpr mice to investigate the potential role of leptin in autoimmunity. C57BL/6J-ob/ob mice were backcrossed with MRL/Mp-Faslpr mice, which develop human systemic lupus erythematosus (SLE)-like lesions. The effects of leptin deficiency on various SLE-like manifestations were investigated in MRL/Mp-Faslpr mice. The regulatory T cell population in the spleen was analyzed by flow cytometry, and the effects of leptin on regulatory T cells and Th17 cells were evaluated in vitro. Compared with leptin-producing MRL/Mp-Faslpr mice, leptin-deficient MRL/Mp-Faslpr mice showed less marked splenomegaly and a particularly low population of CD3+CD4−CD8−B220+ T cells (lpr cells). Their serum concentrations of Abs to dsDNA were lower, and renal histological changes at age 20 wk were ameliorated. Regulatory T cells were increased in the spleens of leptin-deficient MRL/Mp-Faslpr mice. Leptin suppressed regulatory T cells and enhanced Th17 cells in vitro. In conclusion, blockade of leptin signaling may be of therapeutic benefit in patients with SLE and other autoimmune diseases.

CD4+ T-cell dysfunctions through the impaired lipid rafts ameliorate concanavalin A-induced hepatitis in sphingomyelin synthase 1-knockout mice

Membrane microdomains consisting of sphingomyelin (SM) and cholesterol appear to be important for signal transduction in T-cell activation. The present study was designed to elucidate the role of membrane SM in vivo and in vitro using sphingomyelin synthase 1 (SMS1) knock out (SMS1(-/-)) mice and Concanavalin A (ConA)-induced hepatitis. After establishing SMS1(-/-) mice, we investigated CD4+ T-cell functions including proliferation, cytokine production and signal transduction in vivo. We also examined severity of hepatitis, cytokine production in serum and liver after ConA injection at a dose of 20 mg kg(-1). CD4+ T cells from SMS1(-/-) mice showed severe deficiency of membrane SM and several profound defects compared with wild-type controls as follows: (i) cellular proliferation and production of IL-2 and IFN-γ by co-cross-linking of CD3 and CD4; (ii) tyrosine phosphorylation of LAT and its association with ZAP-70; (iii) clustering and co-localization of TCR with lipid rafts. Consistent with these impaired CD4+ T-cell functions in vitro, SMS1(-/-) mice showed decreased serum levels of IL-6 and IFN-γ by ConA injection, which renders SMS1(-/-) mice less sensitive to ConA-induced hepatitis. These results indicated that the deficiency of membrane SM caused the CD4+ T-cell dysfunction through impaired lipid raft function contributed to protection of ConA-induced liver injury, suggesting that the membrane SM is critical for full T-cell activation both in vitro and in vivo.

Skewed Production of IL-6 and TGFβ by Cultured Salivary Gland Epithelial Cells from Patients with Sjögren's Syndrome

Objective To determine the cytokine production profile of cultured salivary gland epithelial (SGE) cells obtained from patients with Sjögrens syndrome (SS). Methods SGE cells obtained from 9 SS patients and 6 normal controls were cultured in the presence of exogenous IFNγ. Cell proliferation and apoptosis in response to IFNγ were determined by WST1 assay and by FACS analysis. The concentrations of IL-6 and TGFβ secreted into culture supernatants were analyzed by ELISA. Results IFNγ did not significantly affect the proliferation or apoptosis of SGE cells. However, IL-6 concentrations were higher, and TGFβ concentrations were lower, in culture supernatants of SGE cells from SS patients than from normal controls. Conclusion Cytokine production by SGE cells from SS patients showed a skewed balance compared with normal controls, with increased IL-6 and decreased TGFβ secretion. This imbalance may be critical in the regulation of Treg/Th17 cells and may foster a pathogenic milieu that may be causative and predictive in SS.

A multicenter phase II prospective clinical trial of glucocorticoid for patients with untreated IgG4-related disease

Abstract Objective: Although glucocorticoids are effective for patients with IgG4-related disease, the treatment has not yet been standardized. Therefore, the treatment strategy should be established. Patients and methods: Patients who fulfilled the comprehensive diagnostic criteria for definite IgG4-related disease were started on prednisolone (0.6 mg/kg body weight) with the dose reduced every two weeks. The subsequent maintenance dose and need for prednisolone were determined for individual patients. The primary endpoint was the complete remission (CR) rate at one year. Secondary endpoints included overall response rate (ORR), the maintenance dose, the relapse rate, and adverse events. Results: This study enrolled 61 patients. After clinicopathological review, three patients were excluded, and one, 13, and 44 patients were diagnosed with probable, possible, and definite IgG4-related disease, respectively. Of the 44 patients with definite IgG4-RD, 29 (65.9%) achieved CR, and the ORR was 93.2%. No patient was refractory to primary treatment. The most frequent adverse events were glucose intolerance. Six patients relapsed. Conclusions: Glucocorticoid treatment is usually effective for patients with IgG4-RD, and we should examine the possibility of other disorders when a patient is glucocorticoid refractory. Some patients are misdiagnosed, making central clinicopathological review of diagnosis very important in conducting clinical studies.

Decreased Expression of Innate Immunity-Related Genes in Peripheral Blood Mononuclear Cells from Patients with IgG4-Related Disease.

Background IgG4-related disease (IgG4-RD) is a new clinical entity of unknown etiology characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. Although aberrancies in acquired immune system functions, including increases in Th2 and Treg cytokines observed in patients with IgG4-RD, its true etiology remains unclear. To investigate the pathogenesis of IgG4-RD, this study compared the expression of genes related to innate immunity in patients with IgG4-RD and healthy controls. Materials and Methods Peripheral blood mononuclear cells (PBMCs) were obtained from patients with IgG4-RD before and after steroid therapy and from healthy controls. Total RNA was extracted and DNA microarray analysis was performed in two IgG4-RD patients to screen for genes showing changes in expression. Candidate genes were validated by real-time RT-PCR in 27 patients with IgG4-RD and 13 healthy controls. Results DNA microarray analysis identified 21 genes that showed a greater than 3-fold difference in expression between IgG4-RD patients and healthy controls and 30 genes that showed a greater than 3-fold change in IgG4-RD patients following steroid therapy. Candidate genes related to innate immunity, including those encoding Charcot–Leyden crystal protein (CLC), membrane-spanning 4-domain subfamily A member 3 (MS4A3), defensin alpha (DEFA) 3 and 4, and interleukin-8 receptors (IL8R), were validated by real-time RT-PCR. Expression of all genes was significantly lower in IgG4-RD patients than in healthy controls. Steroid therapy significantly increased the expression of DEFA3, DEFA4 and MS4A3, but had no effect on the expression of CLC, IL8RA and IL8RB. Conclusions The expression of genes related to allergy or innate immunity, including CLC, MS4A3, DEFA3, DEFA4, IL8RA and IL8RB, was lower in PBMCs from patients with IgG4-RD than from healthy controls. Although there is the limitation in the number of patients applied in DNA microarray, impaired expression of genes related to innate immunity may be involved in the pathogenesis of IgG4-RD as well as in abnormalities of acquired immunity.

High-dose methotrexate with R-CHOP therapy for the treatment of patients with primary central nervous system lymphoma

We describe MR-CHOP therapy, a novel treatment regimen consisting of high-dose methotrexate and R-CHOP that provides systemic anti-tumor activity with penetration of the blood–brain barrier in patients with newly diagnosed primary central nervous system lymphoma. The MR-CHOP regimen was administered with 2 g/m2 of methotrexate and 375 mg/m2 of rituximab on day 1, 750 mg/m2 of cyclophosphamide on day 3, 50 mg/m2 of doxorubicin on day 3, 1.4 mg/m2 of vincristine on day 3 and 100 mg of prednisolone on days 1–5 in this pilot study of seven patients. Six cycles of MR-CHOP therapy were administered every 3 weeks, followed by high-dose chemotherapy with stem cell rescue in young patients, or an additional two cycles of 4 g/m2 methotrexate and rituximab in older patients. The overall response rate was 100%, with 85.7% complete remission (CR). One patient showed partial response, relapsed and subsequently died. Another relapsed following CR, and was rescued by further salvage therapy. The others survive without relapse at a median observation period of 24 months. Hematological toxicity included grade 4 leukocytopenia in 4/7 and neutropenia in 5/7, which were transient and tolerated well. Non-hematological toxicities were tolerated well. The efficacy of this novel regimen as remission induction therapy was found to be promising in this pilot study, although the number of patients was small and follow-up short.

Rapid response of plasmacytomas to lenalidomide plus low-dose dexamethasone therapy in a patient with relapsed multiple myeloma.

To the editor: Plasmacytomas have sometimes been seen at the time of diagnosis or during the course of multiple myeloma (MM) [1,2]. Although the development of multiple plasmacytomas is considered to be associated with aggressive disease and poor prognosis of MM [2], a strategy for MM with multiple plasmacytomas has not been established. Herein, we present a relapsed MM patient who achieved a rapid response of plasmacytomas to lenalidomide plus low-dose dexamethasone (Rd) therapy. A 57-year-old Japanese woman was diagnosed immunoglobulin G lambda-type MM in July 2003. Abnormal cytogenetics including 13q-/-13 were not detected in metaphases. She achieved a complete response with three courses of ranimustine, vincristine, melphalan, and dexamethasone (ROAD) therapy and five courses of bortezomib-based therapy, at diagnosis and at first relapse in 2009, respectively. In December 2010, 7 months after the last chemotherapy, she complained of painless tumors of the head, numbness of the left leg and lumbago. Her serum b2-microglobulin was elevated (5.0 mg/l) and IgA and IgM were suppressed (67 and 33 mg/dl, respectively) while her IgG was normal (1,040 mg/dl). Her hemoglobin and serum albumin were 10.9 and 3.4 g/dl, respectively. Computed tomographic (CT) scan showed three skull tumors (5.0 cm 3 3.5 cm, 2.5 cm 3 0.5 cm, and 1.5 cm 3 0.5 cm, Fig. 1A). FDG-PET/CT scan showed systemic multiple positive lesions, including three skull tumors and systemic bone and bone marrow. She was therefore diagnosed with second relapse of MM with multiple plasmacytomas. Although bortezomib-based multidrug combination therapies are recommended for MM with multiple plasmacytomas [3], we decided on Rd therapy with 40% dose reduction of lenalidomide because she had a history of discontinuation of chemotherapy due to severe adverse events. Lenalidomide (15 mg) and dexamethasone (10 mg) were administered orally on days 1–21 and on days 1, 8, 15, and 22 of each 28-day cycle, respectively. A CT scan on day 20 of the first course of Rd therapy revealed complete disappearance of plasmacytomas of the skull (Fig. 1B). Numbness of the left leg and lumbago also disappeared after the first course of Rd therapy. To date (June 2011), six courses of Rd therapy have been administered without =Grade 3 adverse events and she has been symptom free. Although thalidomide has been considered ineffective for plasmacytomas [2,4] and lenalidomide is an analog of thalidomide, some reports have mentioned the efficacy of lenalidomide for MM with multiple plasmacytomas [5– 9]. Antiangiogenic efficacy of lenalidomide is stronger than that of thalidomide [10], which may be one of the reasons for the clinical efficacy of lenalidomide for plasmacytomas because plasmacytomas have increased angiogenic activity [11]. Furthermore, a rapid response for plasmacytomas and rapid disappearance of symptoms associated with MM suggest that lenalidomide may have direct antiproliferation mechanisms for myeloma cells. In conclusion, this case report indicates that lenalidomide may be a promising agent and Rd therapy may be one of the options for MM with multiple plasmacytomas. Prospective trials should be conducted to confirm the efficacy of lenalidomide-based therapy for MM with multiple plasmacytomas.

Isolation of vascular smooth muscle antigen-reactive CD4(+)αβTh1 clones that induce pulmonary vasculitis in MRL/Mp-Fas(+/+) mice.

Here, we established CD4(+)αβTh1 clones specific for rat vascular smooth muscle antigen (VSMAg) that induced vasculitis lesions in the lungs of MRL/Mp-Fas(+/+) mice following adoptive transfer. Six different T cell clones, MV1b1 (Vβ1), MV1b4 (Vβ4), MV1b8.3 (Vβ8.3), MV1b61 (Vβ6), MV1b62 (Vβ6), and MV1b63 (Vβ6), were isolated from the MV1 T cell line from the regional lymph nodes of immunized MRL/Mp-Fas(+/+) mice; the three (Vβ6) clones had unique CDR3 amino acid sequences. Following stimulation with VSMAg-pulsed antigen presenting cells, MV1b61 and MV1b62 failed to secrete interferon-γ and tumor necrosis factor-α, although the other four clones secreted high levels of both cytokines. In adoptive transfer experiments, MV1b61 and MV1b62 did not induce organ involvement including pulmonary vasculitis. In contrast, MV1b1, MV1b4, MV1b8.3, and MV1b63 induced perivascular mononuclear cell infiltration in pulmonary small arteries. These clones may provide useful tools for investigating the underlying mechanisms of vasculitis syndromes and for developing therapeutic strategies.