Activated autologous T cells exert an anti-B-cell chronic lymphatic leukemia effect in vitro and in vivo.

Background Aims: The impact of chronic lymphatic leukemia (CLL) tumor burden on the autologous immune system has already been demonstrated. This study attempted to elucidate the molecular mechanisms underlying T-cell immunologic deficiencies in CLL.

Methods: Freshly isolated CD3(+) T cells from patients with a diagnosis of CLL and healthy donors were analyzed by gene expression profiling.

Toxic epidermal necrolysis in a patient with primary myelofibrosis receiving thalidomide therapy.

Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm characterized by progressive anemia, massive splenomegaly, leukoerythroblastosis, extramedullary hematopoiesis and in about 50% of cases the presence of JAK2V617F mutation. Curative therapy in PMF is currently possible only with allogeneic haematopoietic stem cell transplantation which is, unfortunately, associated with relatively high risks of mortality and morbidity which undermine its broad applications. Non-transplant treatment modalities are used for palliative purposes.

Constitutively activated Notch signaling is involved in survival and apoptosis resistance of B-CLL cells.

Notch signaling is involved in tumorigenesis, but its role in B-chronic lymphocytic leukemia (B-CLL) pathogenesis is not completely defined. This study examined the expression and activation of Notch receptors in B-CLL cells and the role of Notch signaling in sustaining the survival of these cells. Our results show that B-CLL cells but not normal B cells constitutively express Notch1 and Notch2 proteins as well as their ligands Jagged1 and Jagged2.

Transformation by retroviral vectors of bone marrow-derived mesenchymal cells induces mitochondria-dependent cAMP-sensitive reactive oxygen species production.

Retroviral vectors are used in human gene therapy trials to stably introduce therapeutic genes in the genome of patients' cells. Their applicability, however, is frustrated by the limited viability of transformed cells and/or by risks linked to selection of oncogene-mutated clones. The reasons for these drawbacks are not yet completely understood.

Evidence of jak2 val617phe positive essential thrombocythemia with splanchnic thrombosis during estroprogestinic treatment.

The discovery of the Janus kinase 2 Val617Phe mutation has brought new insights into the development of myeloproliferative disorders; however, the pathogenesis of essential thrombocythemia and its related thrombotic complications has not been completely understood. Although the Janus kinase 2 Val617Phe mutation confirms the initially suspected clonal character of the disease, factors influencing clonal transformation and expansion in the bone marrow have not been fully detected. Furthermore, patients affected by essential thrombocythemia who are carriers of the Janus kinase 2 Val617Phe mutation show a higher incidence of venous thromboembolism both before, and at the time of diagnosis, compared with noncarriers, and recent evidence of splanchnic and cerebral vein thrombosis in carriers of the Janus kinase 2 Val617Phe mutation has been reported.

Sustained long-term engraftment and transgene expression of peripheral blood CD34+ cells transduced with third-generation lentiviral vectors.

As mobilized peripheral blood (MPB) represents an attractive cell source for gene therapy, we investigated the ability of third-generation lentiviral vectors (LVs) to transfer the enhanced green fluorescent protein gene into MPB CD34(+) cells in culture conditions allowing expansion of transplantable human hematopoietic stem cells. To date, few studies have reported transduction of MPB cells with vesicular stomatitis virus G pseudotyped LVs. The critical issue remains whether primitive, hematopoietic repopulating cells have, indeed, been transduced.

Endothelial differentiation of hematopoietic stem and progenitor cells from patients with multiple myeloma.

Purpose: Vasculogenesis is a physiologic process typical of fetal development in which new blood vessels develop from undifferentiated precursors (or angioblasts). In tumors, near angiogenesis, vasculogenesis contributes to the formation of the microvascular plexus that is important for diffusion. Here, we show that hematopoietic stem and progenitor cells (HSPC) of multiple myeloma (MM) patients are able to differentiate into cells with endothelial phenotype on exposure to angiogenic cytokines.

Eubacterium plautii infection in a kidney transplant recipient: a noteworthy case of pleural effusion and fever.

We report a noteworthy case of Eubacterium plautii infection after kidney transplantation. Our 33-yr-old transplant recipient received standard care; his post-transplant course was uneventful. However, on day 44 he underwent an emergency laparotomy for perforation of the ileum.

Mesenchymal cells recruit and regulate T regulatory cells.

Objective: Despite much investigation into T regulatory cells (Tregs), little is known about the mechanism controlling their recruitment and function. Because multipotent mesenchymal stromal cells (MSCs) exert an immune regulatory function and suppress T-cell proliferation, this in vitro study investigated their role in Treg recruitment and function.

Materials And Methods: Human MSCs and different T cell populations (CD3(+), CD3(+)/CD45RA(+), CD3(+)/CD45RO(+), CD4(+)/CD25(+), CD4(+)/CD25(+)/CD45RO(+), CD4(+)/CD25(+)/CD45RA(+)) from healthy donors were cocultured for up to 15 days.

Hematopoietic stem cell transplantation from alternative donors for high-risk acute leukemia: the haploidentical option.

Much progress has been made in the clinical, biological and technical aspects of the T-cell-depleted full-haplotype mismatched transplants for acute leukemia. Our experience demonstrates that infusing a megadose of extensively T-cell-depleted hematopoietic peripheral blood stem cells after an immuno-myeloablative conditioning regimen in acute leukemia patients ensures sustained engraftment with minimal graft-vs-host disease (GvHD) without the need of any post-transplant immunosuppressive treatment. Since our first successful pilot study, our efforts have concentrated on developing new conditioning regimens, optimizing the graft processing and improving the post-transplant immunological recovery.

Role of reactive oxygen species as signal molecules in the pre-commitment phase of adult stem cells.

This mini-review summarizes evidence, provided by our group, relevant to the understanding of how redox signalling may control the fate of adult hematopoietic stem/progenitor cells (HSPCs). In particular it is shown that bone marrow-derived human HSPC are endowed with a composite panel of constitutively active NADPH-oxidases (NOXs) comprising the cell membrane-localized catalytic subunits of the NOX1, NOX2 and NOX4 isoforms. It is proposed that the coordinated activity of the NOX isoforms in HSPCs function as environmental oxygen sensor and generate low level of ROS, which likely serve as second messengers.

Sustained ventricular tachycardia in a thalidomide-treated patient with primary plasma-cell leukemia.

Background: A 68-year-old man diagnosed with primary plasma-cell leukemia was given thalidomide maintenance treatment for his disease. He had previously failed induction therapy with cyclophosphamide, vincristine, adriamycin, and dexamethasone, but achieved complete remission after melphalan therapy. Multiple syncopal episodes started to occur during thalidomide treatment, and a Holter electrocardiogram showed multiple abnormalities, with an episode of sustained ventricular tachycardia.

Large-scale generation of human allodepleted anti-3rd party lymphocytes.

Although adoptive transfer of donor lymphocytes protects from infections and relapse after allogeneic hematopoietic stem cell transplantation in both mice and in men, it is associated with a high risk of graft versus host disease (GvHD) which rises with HLA mismatching and the number of T lymphocytes that are infused. Elimination/reduction of alloreactive donor T lymphocytes is an appealing approach and several strategies have been proposed. Here we describe generation of anti-3rd party T lymphocytes under conditions of IL-2 deprivation and their effects in a pre-clinical murine model.

The hypoxia-inducible factor is stabilized in circulating hematopoietic stem cells under normoxic conditions.

The hypoxia-inducible factor (HIF) transcriptional system enables cell adaptation to limited O(2) availability, transducing this signal into patho-physiological responses such as angiogenesis, erythropoiesis, vasomotor control, and altered energy metabolism, as well as cell survival decisions. However, other factors beyond hypoxia are known to activate this pleiotropic transcription factor. The aim of this study was to characterize HIF in human hematopoietic stem cells (HSCs) and evidence is provided that granulocyte colony stimulating factor-mobilized CD34+- and CD133+-HSCs express a stabilized cytoplasmic form of HIF-1alpha under normoxic conditions.

Loss of bone mineral density and secondary hyperparathyroidism are complications of autologous stem cell transplantation.

Patients who underwent autologous stem cell transplantation (ASCT) are prone to decreased bone mineral density (BMD). We measured BMD in 180 patients who underwent ASCT for hematologic malignancies. Patients were evaluated with a median of 6.

The proteasome inhibitor bortezomib affects osteoblast differentiation in vitro and in vivo in multiple myeloma patients.

The proteasome inhibitor bortezomib may increase osteoblast-related markers in multiple myeloma (MM) patients; however, its potential osteoblastic stimulatory effect is not known. In this study, we show that bortezomib significantly induced a stimulatory effect on osteoblast markers in human mesenchymal cells without affecting the number of osteoblast progenitors in bone marrow cultures or the viability of mature osteoblasts. Consistently we found that bortezomib significantly increased the transcription factor Runx2/Cbfa1 activity in human osteoblast progenitors and osteoblasts without affecting nuclear and cytoplasmatic active beta-catenin levels.

Bone-marrow derived hematopoietic stem/progenitor cells express multiple isoforms of NADPH oxidase and produce constitutively reactive oxygen species.

Consolidated evidence highlights the importance of redox signalling in poising the balance between self-renewal and differentiation in adult stem cells. The present study shows that human hematopoietic stem/progenitor cells (HSCs) constitutively generate low levels of hydrogen peroxide whose production is inhibited by DPI, apocynin, catalase, and LY294002 and scarcely stimulated by PMA. Moreover, it is shown that HSCs express at the mRNA and protein levels the catalytic subunits of NOX1, NOX2, and NOX4 isoforms of the NADPH oxidase family along with the complete battery of the regulatory subunits p22, p40, p47, p67, rac1, rac2, NOXO1, and NOXA1 as well as the splicing variant NOX2s and that the three NOX isoforms are largely co-expressed in the same HSC.

Interleukin-7-engineered mesenchymal cells: in vitro effects on naive T-cell population.

T-cell homeostasis is regulated by several molecules; among these, interleukin (IL)-7 plays an essential role in the survival and homeostatic proliferation of peripheral naive T cells. In a previous study, we investigated whether human mesenchymal stromal cells (MSCs) could be engineered with the IL-7 gene to produce functional level of this cytokine. In the present study, we analyzed the impact of different quantities of IL-7 produced by MSCs on the survival and proliferation of a negative immunoselected naive (CD3(+)/CD45RA(+)) T-cell population.

MEK1 inhibition sensitizes primary acute myelogenous leukemia to arsenic trioxide-induced apoptosis.

We found that MEK1 inhibitor PD184352 strikingly increased apoptosis induced by arsenic trioxide (ATO) in 21 of 25 patients with primary acute myelogenous leukemia (AML). Isobologram analysis confirmed the synergistic (13 of 25 patients) or additive (8 of 25 patients) nature of this interaction. Moreover, we demonstrated that the p53-related gene p73 is a molecular target of the combined treatment in AML blasts.

Unique human CD133+ leukemia cell line and its modulation towards a mesenchymal phenotype by FGF2 and TGFbeta1.

Immunological features of GM-490 cells, a new blood cell line from a patient with acute lymphoblastic leukemia, included lack of CD34, CD38, CD45, CD14, HLA-DR, and lymphoid and myeloid markers and expression of CD29, CD36, CD44, CD54, CD71, CD105, and CD133. Molecular analysis indicated CD45 gene expression was absent but CD34 mRNA was present. GM-490 cells constitutively produced fibronectin (FN), type III and traces of type I collagen, collagenases, glycosaminoglycans (GAG) and biglycan and betaglycan proteoglycans (PG) as well as FGF2 and TGFbeta1.

Large-scale preparation of human anti-third-party veto cytotoxic T lymphocytes depleted of graft-versus-host reactivity: a new source for graft facilitating cells in bone marrow transplantation.

Induction of donor type chimerism in mildly prepared hosts without graft-versus-host disease (GvHD) is a most desirable goal in bone morrow transplantation. We have recently demonstrated in a mouse model that donor veto cytotoxic T lymphocytes (CTLs) can facilitate the induction of donor type chimerism in sublethally irradiated recipients without causing GvHD if they are effectively depleted of alloreactivity against host cells by means of stimulation against a third party. We extend this approach to human cells, by preparing CTLs in two major steps: primary culture in the absence of interleukin 2, leading to death by neglect of antihost clones, and addition of interleukin 2 and subsequent dilution of antihost clones as a consequence of the expansion of the anti-third-party clones.