CD2 ؉ T lymphocytes obtained from either the donor of bone marrow stromal cells (BMSCs) or a third party were cultured in mixed lymphocyte reactions (MLRs) with either allogeneic dendritic cells (DCs) or peripheral blood lymphocytes (PBLs). When autologous or allogeneic BMSCs were added back to T cells stimulated by DCs or PBLs, a significant and dosedependent reduction of T-cell proliferation, ranging from 60% ؎ 5% to 98% ؎ 1%, was evident. Similarly, addition of BMSCs to T cells stimulated by polyclonal activators resulted in a 65% ؎ 5% (P ‫؍‬ .0001) suppression of proliferation. BMSCinduced T-cell suppression was still evident when BMSCs were added in culture as late as 5 days after starting of MLRs. BMSC-inhibited T lymphocytes were not apoptotic and efficiently proliferated on restimulation. BMSCs significantly suppressed both CD4 ؉ and CD8 ؉ T cells (65% ؎ 5%, [P ‫؍‬ .0005] and 75% ؎ 15% [P ‫؍‬ .0005], respectively). Transwell experiments, in which cell-cell contact between BMSCs and effector cells was prevented, resulted in a significant inhibition of T-lymphocyte proliferation, suggesting that soluble factors were involved in this phenomenon. By using neutralizing monoclonal antibodies, transforming growth factor ␤1 and hepatocyte growth factor were identified as the mediators of BMSC effects. In conclusion, our data demonstrate that (1) autologous or allogeneic BMSCs strongly suppress T-lymphocyte proliferation, (2) this phenomenon that is triggered by both cellular as well as nonspecific mitogenic stimuli has no immunologic restriction, and (3) T-cell inhibition is not due to induction of apoptosis and is likely due to the production of soluble factors. (Blood. 2002;99:3838-3843)

In a large general-practice cohort of patients with multiple cardiovascular risk factors, daily treatment with n-3 fatty acids did not reduce cardiovascular mortality and morbidity. (Funded by Società Prodotti Antibiotici and others; ClinicalTrials.gov number, NCT00317707.).

Myeloid-derived suppressor cells (MDSCs) are powerful immunomodulatory cells that in mice play a role in infectious and inflammatory disorders, including acute graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. Their relevance in clinical acute GVHD is poorly known. We analyzed whether granulocyte colony-stimulating factor (G-CSF) administration, used to mobilize hematopoietic stem cells, affected the frequency of MDSCs in the peripheral blood stem cell grafts of 60 unrelated donors. In addition, we evaluated whether the MDSC content in the peripheral blood stem cell grafts affected the occurrence of acute GVHD in patients undergoing unrelated donor allogeneic stem cell transplantation. Systemic treatment with G-CSF induces an expansion of myeloid cells displaying the phenotype of monocytic MDSCs (Lin(low/neg)HLA-DR(-)CD11b(+)CD33(+)CD14(+)) with the ability to suppress alloreactive T cells in vitro, therefore meeting the definition of MDSCs. Monocytic MDSC dose was the only graft parameter to predict acute GVHD. The cumulative incidence of acute GVHD at 180 days after transplantation for recipients receiving monocytic MDSC doses below and above the median was 63% and 22%, respectively (P = .02). The number of monocytic MDSCs infused did not impact the relapse rate or the transplant-related mortality rate (P > .05). Although further prospective studies involving larger sample size are needed to validate the exact monocytic MDSC graft dose that protects from acute GVHD, our results strongly suggest the modulation of G-CSF might be used to affect monocytic MDSCs graft cell doses for prevention of acute GVHD.

Adenovirus-transduced CD34 IntroductionGenetically modified stem/progenitor cells represent an innovative approach for delivery of anticancer molecules. 1,2 Because of their homing properties, systemically injected stem/progenitor cells could infiltrate both primary and metastatic tumor sites, thus allowing tumor-specific targeting 3-9 and potentially overcoming limitations inherent to the pharmacokinetic profile of soluble drugs. [10][11][12] Soluble tumor necrosis factor (TNF)-related apoptosisinducing ligand (sTRAIL) is a proapoptotic member of the TNF superfamily of death receptor ligands. A variety of preclinical data show that sTRAIL is a cancer cell-specific molecule exerting a remarkable antitumor activity in vitro [13][14][15][16][17][18] and in vivo in athymic nude mice or in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. 13,19,20 Phase 1/2 clinical trials have demonstrated a good toxicity profile for sTRAIL but limited evidence of antitumor activity probably because of short exposure of tumor cells to low drug concentrations. 21 Because of sTRAIL's short half-life, 13,20,22 it seems unlikely that the recommended sTRAIL dose of 8 mg/kg body weight will allow prolonged exposure of tumor cells at high drug concentrations. 21 Strategies to enhance the therapeutic activity of sTRAIL include combining it with conventional chemotherapy 23 or with new agents, such as histone deacetylase inhibitors that up-regulate TRAIL-R1 and/or TRAIL-R2, resulting in a synergistic induction of apoptosis in both sTRAIL-sensitive and -resistant tumor cells. 24 Alternatively, cell-based vehiculation of the full-length, membranebound (m)TRAIL has been proposed. 11 Neural or mesenchymal stem cell-mediated mTRAIL delivery has been investigated in solid tumors. 9,[25][26][27][28] More recently, we demonstrated that intravenous injection of mTRAIL-expressing CD34 ϩ cells (CD34-TRAIL ϩ cells) efficiently act as mTRAIL-presenting vehicles and exert a potent antitumor activity in NOD/SCID mice bearing systemic multiple myeloma and non-Hodgkin lymphoma xenografts. [29][30][31] Using a subcutaneous multiple myeloma model in NOD/SCID mice, the present study aimed at investigating the antitumor mechanism(s) of mTRAIL-expressing cells by analyzing homing properties of CD34-TRAIL ϩ cells as well as the degree and distribution of tumor cell death and tumor vascular damage. To analyze the antivascular activity of CD34-TRAIL ϩ cells, we used an in vivo staining assay of tumor vasculature. 32 The imaging software ImageJ (National Institutes of Health), equipped with appropriately designed macros to specifically quantify parameters of tumor cell and tumor vascular damage, allowed the processing The online version of this article contains a data supplement.The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. For personal use only. on May 11, 2018. by guest www.blood...