Nonpeghylated liposomal doxorubicin combination regimen (R-COMP) for the treatment of lymphoma patients with advanced age or cardiac comorbidity.

Doxorubicin is the most effective single agent in the treatment of non-Hodgkin's lymphoma (NHL). Its use is limited because of the cardiac toxicity primarily in elderly patients (pts) and in pts with history of cardiac disease. Liposomal doxorubicin has been proven to reduce cardiotoxicity. The aim of this retrospective study was the use of nonpeghylated liposomal doxorubicin (NPLD) in term of efficacy, response rate and incidence of cardiac events. We retrospectively collected the experience of 33 Hematological Italian Centers in using NPLD. Nine hundred and forty-six consecutive pts treated with R-COMP (doxorubicin was substituted with NPLD, Myocet) were collected. Median age was 74 years, the reasons for use of NPLD were: age (466 pts), cardiac disease (298 pts), uncontrolled hypertension (126 pts), other reasons (56 pts). According to clinicians' evaluation, 49.9% of pts would not have used standard doxorubicin for different situations (age, cardiomyopathy, previous use of doxorubicin, and uncontrolled hypertension). Overall 687 pts (72.6%) obtained a complete remission (CR). About 5% (n = 51) of subjects developed major cardiotoxic events including heart failure (N = 31), ischemic heart disease (N = 16), acute heart attack (N = 3), and acute pulmonary oedema (N = 1). After a median follow-up of 32 months, 651 pts were alive and the overall survival (OS) was 72%. After a median observation period of 23 months disease free survival (DFS) was 58%. Either in univariate or in multivariate analysis OS and DFS were not significantly affected by age or cardiac disease. Our findings strongly support that including R-COMP is effective and safe when the population is at high risk of cardiac events and negatively selected. Moreover, the use of this NPLD permitted that about half of our population had the opportunity to receive the best available treatment.

Tregs prevent GVHD and promote immune reconstitution in HLA-haploidentical transplantation.

Hastening posttransplantation immune reconstitution is a key challenge in human leukocyte antigen (HLA)-haploidentical hematopoietic stem-cell transplantation (HSCT). In experimental models of mismatched HSCT, T-regulatory cells (Tregs) when co-infused with conventional T cells (Tcons) favored posttransplantation immune reconstitution and prevented lethal graft-versus-host disease (GVHD). In the present study, we evaluated the impact of early infusion of Tregs, followed by Tcons, on GVHD prevention and immunologic reconstitution in 28 patients with high-risk hematologic malignancies who underwent HLA-haploidentical HSCT. We show for the first time in humans that adoptive transfer of Tregs prevented GVHD in the absence of any posttransplantation immunosuppression, promoted lymphoid reconstitution, improved immunity to opportunistic pathogens, and did not weaken the graft-versus-leukemia effect. This study provides evidence that Tregs are a conserved mechanism in humans.

CD34+ cells from AML with mutated NPM1 harbor cytoplasmic mutated nucleophosmin and generate leukemia in immunocompromised mice.

Acute myeloid leukemia (AML) with mutated NPM1 shows distinctive biologic and clinical features, including absent/low CD34 expression, the significance of which remains unclear. Therefore, we analyzed CD34(+) cells from 41 NPM1-mutated AML. At flow cytometry, 31 of 41 samples contained less than 10% cells showing low intensity CD34 positivity and variable expression of CD38. Mutational analysis and/or Western blotting of purified CD34(+) cells from 17 patients revealed NPM1-mutated gene and/or protein in all. Immunohistochemistry of trephine bone marrow biopsies and/or flow cytometry proved CD34(+) leukemia cells from NPM1-mutated AML had aberrant nucleophosmin expression in cytoplasm. NPM1-mutated gene and/or protein was also confirmed in a CD34(+) subfraction exhibiting the phenotype (CD34(+)/CD38(-)/CD123(+)/CD33(+)/CD90(-)) of leukemic stem cells. When transplanted into immunocompromised mice, CD34(+) cells generated a leukemia recapitulating, both morphologically and immunohistochemically (aberrant cytoplasmic nucleophosmin, CD34 negativity), the original patient's disease. These results indicate that the CD34(+) fraction in NPM1-mutated AML belongs to the leukemic clone and contains NPM1-mutated cells exhibiting properties typical of leukemia-initiating cells. CD34(-) cells from few cases (2/15) also showed significant leukemia-initiating cell potential in immunocompromised mice. This study provides further evidence that NPM1 mutation is a founder genetic lesion and has potential implications for the cell-of-origin and targeted therapy of NPM1-mutated AML.

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. Harvested lymphocytes were analyzed by flow cytometry and FoxP3 and CD127 expressions were measured by real-time polymerase chain reaction. Their regulatory activity was assessed. RESULTS: We demonstrate MSC recruit Tregs from a fraction of CD3(+) and from immunoselected CD3(+)/CD45RA(+) and CD3(+)/CD45RO(+) fractions. After culture with MSCs both immunoselected fractions registered increases in the CD4(+)/CD25(bright)/FoxP3 subset and CD127 expression was downregulated. When purified Treg populations (CD4/CD25(+), CD4/CD25(+)/CD45RA(+), and CD4/CD25(+)/CD45RO(+)) are used in MSC cocultures, they maintain FoxP3 expression and CD127 expression is downregulated. Treg suppressive capacity was maintained in Treg populations that were layered on MSC for up to 15 days while control Tregs lost all suppressive activity after 5 days culture. CONCLUSIONS: In conclusion, our study demonstrates that MSCs recruit, regulate, and maintain T-regulatory phenotype and function over time.

Interleukin 7-engineered stromal cells: a new approach for hastening naive T cell recruitment.

In this study we determined whether human stromal cells could be engineered with a retroviral vector carrying the interleukin 7 (IL-7) gene and investigated the effects on T cells in vitro and in vivo in a murine model. Transduced mesenchymal cells strongly express CD90 (98.15%), CD105 (87.6%), and STRO-1 (86.7%). IL-7 production was 16.37 (+/-2 SD) pg/ml, which remained stable for 60 days. In vitro-immunoselected naive T cells maintained the CD45RA+ CD45RO- naive phenotype (4.2 times more than controls) after 7 days of culture with IL-7-engineered stromal cells. The apoptosis rate (4.7%) of the naive T cells cultured with transduced stromal cells overlapped with that of freshly isolated cells. Immunohistological analysis detected stromal cells in bone marrow, spleen, and thymus. Cotransplantation of IL-7-engineered stromal cells with CD34+ cells improved engraftment in terms of CD45+ cells and significantly increased the CD3+ cell count in peripheral blood, bone marrow, and spleen. These data demonstrate the following: (1) human stromal cells can be transduced, generating a normal layer; (2) transduced stromal cells in vitro maintain the naive T cell phenotype; and (3) IL-7-transduced stromal cells in vivo home to lymphoid organs and produce sufficient IL-7 in loco, supporting T cell development in a cotransplantation model. Because of their efficient cytokine production and homing, IL-7-engineered stromal cells might be an ideal vehicle to hasten immunological reconstitution in T cell-depleted hosts.

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. Our results clearly indicated that anti-3rd party T lymphocytes generated on a large scale by means of IL-2 deprivation maintain a broad T cell repertoire, do not proliferate in a mixed lymphocyte reaction and do not cause GvHD in NOD-SCID mice. These anti-3rd party lymphocytes contain a large adaptive T regulatory cell subset which might contribute to in vitro and in vivo immune modulation.

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. When FGF2 and/or TGFbeta1 were added to cells in vitro, they stimulated cell proliferation and differently modulated matrix production and growth factor receptor expression. Reverse transcription-polymerase chain reaction (RT-PCR) detection of transcripts encoding for osteocalcin and RUNX2 suggests GM-490 cells differentiate towards the osteoblast pathway. GM-490 cells expressed the low affinity nerve growth factor receptor (p75LNGFR), a somatic stem cell marker that is not detected in hematopoietic cells, leading to the hypothesis that GM-490 has mesenchymal stem cell properties. The reciprocal modulating effects of FGF2 and TGFbeta1 on each other's receptors make the GM-490 cell line a new model for investigating the relationship between these growth factors and their receptors in autocrine loops which are believed to sustain the malignant clone in hematological diseases.

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. Co-cultivation of peripheral naive T cells with MSCs producing low (16 pg/mL) or high (1000 pg/mL) IL-7 levels or in the presence of exogenous IL-7 (0.01 ng/mL and 100 ng/mL) maintained the CD3(+)/CD45RA(+) naive T-cell phenotype. Chemokine receptor CCR7(+) expression was also maintained among this T-cell population. Naive T-cell molecular characteristics were maintained as assessed by the Vbeta spectratyping complexity score, which showed the maintenance of a broad T-cell repertoire. No Th1 or Th2 differentiation was observed, as assessed by interferon-gamma or IL-4 accumulation. In contrast, only MSCs producing high amounts of IL-7 caused increased activation (CD25 31.2% +/- 12% vs 10% +/- 3.5%; P < .05), proliferation (CD71 17.8+/-7% vs 9.3%+/-3, P < .05), apoptosis (assessed by annexin V: 18.6% +/- 5% vs 14.9% +/- 2.6%; P > .05), and the phase S cell cycle (15% vs 6.9%, P > .05). Exogenous IL-7 exhibited no significant effect. In conclusion, we demonstrated that IL-7 produced by MSCs has a dose-independent effect on naive T-cell survival while exerting a dose-dependent effect on activation/proliferation. Due to the continuous production of IL-7 by engineered cells, our system is more efficacious than exogenous IL-7.

Graft engineering for allogeneic haploidentical stem cell transplantation.

Haploidentical stem cell transplantation has became a clinical reality in the last 10 years as it provides the chance of transplant for about 50% of patients with hematological malignancies who do not have a matched related or unrelated donor. Proper graft preparation for this type of transplant is crucial and this paper analyses our work over the past decade in the search for the optimal graft processing procedure moving from E-rosetting and soybean agglutination, through a combination of negative or positive selection of hematopoietic stem cells to the current method of one-step positive selection. In preparing a graft for haploidentical transplant, three essential requisites must be met. It must contain (1) a megadose (>10 x 10(6) x kg recipient b.w.) of hematopoietic stem cells to overcome the HLA histocompatibility barrier; (2) very few T-lymphocytes (CD3+ cells < 3 x 10(4)/kg recipient b.w.) to prevent severe acute and chronic graft-versus-host disease (GvHD); (3) very few B-lymphocytes to prevent Epstein-Barr virus-related lymphoproliferative disorders. With current graft processing technologies based on positive selection of hematopoietic stem cells, these requirements can be met. A 70-80% hematopoietic stem cell recovery ensures the target megadose is achieved in over 70% of cases with a T-cell depletion of more than 4 logs and a B-cell depletion of over 3 logs. Progress in graft processing has ensured primary, sustained engraftment rates of over 90% and has significantly reduced the incidence of severe acute GvHD and EBV-related lymphoproliferative disorders. Modern time-saving automated graft processing devices ensure reproducibility, reliability, and biological safety, which make widespread application of the haploidentical transplant currently feasible.