Akiko Meguro

Mesenchymal stromal cells inhibit Th17 but not regulatory T-cell differentiation

BACKGROUND AIMS A previous study has demonstrated that mouse mesenchymal stromal cells (MSC) produce nitric oxide (NO), which suppresses signal transducer and activator of transcription (STAT) 5 phosphorylation and T-cell proliferation under neutral and T helper 1 cells (Th1) conditions. We aimed to determine the effects of MSC on T helper 17 cells (Th17) and regulatory T-cell (T-reg) differentiation. METHODS CD4 T cells obtained from mouse spleen were cultured in conditions for Th17 or Treg differentiation with or without mouse MSC. Th17 and Treg differentiation was assessed by flow cytometry using antibodies against interleukin (IL)-17 and forkhead box P3 (Foxp3), a master regulator of Treg cells. RESULTS MSC inhibited Th17 but not Treg differentiation. Under Th17 conditions, MSC did not produce NO, and inhibitors of indoleamine-2,3-dioxygenase (IDO) and prostaglandin E(2) (PGE2) both restored MSC suppression of differentiation, suggesting that MSC suppress Th17 differentiation at least in part through PGE2 and IDO. CONCLUSIONS Our results suggest that MSC regulate CD4 differentiation through different mechanisms depending on the culture conditions.

Mechanisms of Immunomodulation by Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have been identified in animals, especially in bone marrow. As stem cells, they have the ability to differentiate into multiple cell types. This potential raises exciting therapeutic possibilities. A recent report described the successful use of MSCs for the treatment of graft-versus-host disease; however, the scientific community has yet to define the molecular mechanisms of immunomodulation by MSCs. This review summarizes what is known and discusses the conflicting data with regard to the mechanisms of immunomodulation by MSCs.

Rituximab plus 70% cyclophosphamide, doxorubicin, vincristine and prednisone for Japanese patients with diffuse large B-cell lymphoma aged 70 years and older

Abstract In the rituximab era, several large studies have suggested that full-dose rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) might be the best treatment for patients with diffuse large B-cell lymphoma (DLBCL) aged 60 years and older. However, it remains unclear whether this is also the case for those aged 70 years and older. Previously untreated patients with DLBCL aged 70 years and older (elderly) were treated with R-70%CHOP, and patients younger than 70 years (younger) were treated with full-dose R-CHOP every 3 weeks, for a total of 6–8 cycles. Complete remission (CR) rates in elderly versus younger patients were 75 vs. 78% (p = 0.7), respectively. The 3-year overall survival, event-free survival and progression-free survival of elderly versus younger patients were 58 vs. 78% (p < 0.05), 45 vs. 70% (p < 0.05) and 64 vs. 72% (p = 0.43), respectively. Severe adverse events were more frequent in the elderly, even with the dose reduction in that age group. Three-year PFS with R-70%CHOP for patients aged 70 years and older was not significantly worse than that with full-dose R-CHOP for younger patients, suggesting that R-70% CHOP might be a reasonable choice for patients with DLBCL aged 70 years and older, especially for those with comorbidities.

IL-21 is critical for GVHD in a mouse model

Immunological effects of IL-21 on T, B and natural killer (NK) cells have been reported, but the role of IL-21 in GVHD remains obscure. Here, we demonstrate that morbidity and mortality of GVHD was significantly reduced after BMT with splenocytes from IL-21R−/− mice compared with those from wild type mice. To further confirm our observation, we generated a decoy receptor for IL-21. GVHD was again less severe in mice receiving BM cells transduced with the IL-21 decoy receptor than control mice These results suggest that IL-21 critically regulates GVHD, and that blockade of the IL-21 signal may represent a novel strategy for the prophylaxis for GVHD.

Altered effector CD4+ T cell function in IL-21R-/- CD4+ T cell-mediated graft-versus-host disease.

We previously showed that transplantation with IL-21R gene-deficient splenocytes resulted in less severe graft-versus-host disease (GVHD) than was observed with wild type splenocytes. In this study, we sought to find mechanism(s) explaining this observation. Recipients of donor CD4+ T cells lacking IL-21R exhibited diminished GVHD symptoms, with reduced inflammatory cell infiltration into the liver and intestine, leading to prolonged survival. After transplantation, CD4+ T cell numbers in the spleen were reduced, and MLR and cytokine production by CD4+ T cells were impaired. These results suggest that IL-21 might promote GVHD through enhanced production of effector CD4+ T cells. Moreover, we found that CD25 depletion altered neither the impaired MLR in vitro nor the ameliorated GVHD symptoms in vivo. Thus, the attenuated GVHD might be caused by an impairment of effector T cell differentiation itself, rather than by an increase in regulatory T cells and suppression of effector T cells.

Lack of IL-21 signal attenuates graft-versus-leukemia effect in the absence of CD8 T-cells.

Previously, we have shown that IL-21R−/− splenocytes ameliorate GVHD as compared with wild-type splenocytes. Here, we investigated whether or not IL-21R−/− splenocytes diminish the graft-versus-leukemia (GVL) effect. Surprisingly, IL-21R−/− splenocytes efficiently eliminate leukemic cells as well as wild-type splenocytes, suggesting the retention of GVL effects in the absence of IL-21 signaling. To compare the GVL effect between IL-21R−/− and wild-type cells, we titrated the number of splenocytes required for the elimination of leukemic cells and found that the threshold of GVL effect was obtained between 5 × 105 and 5 × 106 with both types of splenocytes. Cotransplantation with CD8-depleted splenocytes but not with purified CD8 T-cells resulted in a significant reduction in anti-leukemic effect of IL-21R−/− cells compared with wild-type cells, suggesting that the lack of IL-21 signaling primarily impairs CD4 T-cell rather than CD8 T-cell function and the comparable GVL effect with IL-21R−/− bulk splenocytes results from cooperative compensation by CD8 T-cells.

Screening of genes responsible for differentiation of mouse mesenchymal stromal cells by DNA micro-array analysis of C3H10T1/2 and C3H10T1/2-derived cell lines

BACKGROUND The molecular mechanisms underlying the biologic effects or differentiation of mesenchymal stromal cells (MSC) have not been clarified. Screening for genes differentially expressed at different stages is an important step in determining these molecular mechanisms. METHODS In this study, we analyzed the gene expression profiles of C3H10T1/2 (10T1/2) cells and two sublines, A54 (pre-adipocyte) and M1601 (myoblast), as a model of MSC and downstream committed progenitors. RESULTS We found up-regulated expression of delta-like-1 (Dlk), Wnt-5a and IL-1 receptor-like-1 (ST2) in 10T1/2 cells; stem cell factor (SCF) and stromal derived factor-1 (SDF-1) in A54 cells; and cardiac muscle-specific gene in M1601 cells. Overexpression of Dlk in A54 cells did not induce any effects on their differentiation into adipocytes. After differentiation into adipocytes, A54 cells reduced the expression of SCF, SDF-1 and Ang-1 as well as the ability to support the formation of a cobblestone appearance. DISCUSSION The results suggest that these three lines hae different gene profiles and are a useful system for analyzing the differentiation and function of MSC and progenitor cells.

Analysis of hemolysis in collected bone marrow for bone marrow transplantation

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Sperm cryopreservation in patients with hematologic malignancies

see front matter 2013 Elsevier Ltd. All rights r http://dx.doi.org/10.1016/j.transci.2013.02.045 To the editor, Recently, the Japanese Marrow Donor Program (JMDP) reported that 3 patients with transplanted hemolyzed bone marrow (BM) showed severe adverse effects related to hemolysis [1]. In these cases, each BM was collected in a hospital and then shipped to another hospital where a patient had received conditioning. BM harvest and shipping were conducted according to the JMDP manual. Collected BM was infused directly into each patient because of ABO blood type compatibility. A hemolytic reaction was suspected just after the beginning of BM infusion based on symptoms such as nausea, vomiting, and blood pressure fluctuation and signs such as hematuria and an increase in serum lactic acid dehydrogenase (LDH) levels and total bilirubin values. Finally, hemolysis in the bags

Prognostic impact of serum soluble interleukin-2 receptor level at diagnosis in elderly patients with diffuse large B-cell lymphoma treated with R-CHOP

Many patients with acute leukemia or lymphoma are cured by chemotherapy or conditioning followed by hemopoietic stem cell transplantation. However, cancer chemotherapies and conditioning regimens deteriorate spermatogenesis. The greatest risk of infertility caused by chemotherapy is associated with alkylating agents such as cyclophosphamide, busulfan and melphalan, which are frequently used as conditioning in hemopoietic stem cell transplantation [1, 2]. Cyclophosphamide is the key drug for treatment of nonHodgkin lymphoma. Non-alkylating drugs such as anthracylines and cytarabine have been shown to have less effect or only a transient adverse effect on sperm production in children with acute leukemia [3, 4]. However, there are few reports on sperm production in adults with acute leukemia. Recently, Bahadur et al. [5] showed that gonadal toxic treatment for adult patients with leukemia or lymphoma results in significant reduction in sperm quality. Similar results were reported by Lemez and Urbanek [6]. Obviously, the best way to rescue infertility in adult male patients with leukemia, lymphoma or related disorders is sperm cryopreservation before the start of chemotherapy [7, 8]. We previously reported the results of a preliminary study showing that it is difficult to obtain the normal number of sperms in heavily treated patients with hematologic malignancies [9]. In this report, we summarize data on sperm collected for cryopreservation from patients with hematologic malignancies and describe successful spouse pregnancy using cryopreserved sperm from a patient with acute myeloid leukemia (AML). Before the start of initial chemotherapy, patients were informed of adverse effects related to chemotherapy, including mucositis, diarrhea, infections, secondary malignancies, and infertility. When male patients expressed a desire to cryopreserve their sperm, they were referred to private clinics conducting sperm banking. Data on sperm concentration and motility before cryopreservation were obtained from each clinic by letters in reply. From January 1999 to December 2007, sperm cryopreservation was performed for 38 patients with hematologic malignancies. Data on sperm from six patients previously reported [9] were included. The patients were divided into two groups: one group of the patients whose sperm was cryopreserved before the start of initial chemotherapy and another group of the patients whose sperm was cryopreserved after chemotherapy had been undertaken. Table 1 shows a summary of sperm conditions in the untreated patients. Six patients had AML including acute promyelocytic leukemia, two had acute lymphoblastic leukemia (ALL), eight had nonHodgkin lymphoma (NHL), five had lymphoblastic lymphoma (LBL) and one had myelodysplastic syndrome. The median age of the untreated patients was 27.5 years. All except two patients showed normal sperm concentration and motility. One patient (case 2) had normal sperm concentration but deteriorated sperm motility, while another (case 15) had extreme oligospermia. Table 2 shows a summary of sperm conditions in the treated patients. The treated patients included seven patients with AML, three with ALL, one with chronic myelogeneous leukemia, two with NHL and three with LBL. The median age of the treated patients was 32 years. Semen was repeatedly A. Meguro K. Muroi (&) T. Matsuyama M. Mori T. Nagai K. Ozawa Division of Hematology, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan e-mail: muroi-kz@jichi.ac.jp