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A Delforge

Publications and source records attributed to A Delforge.

At least 19 recordsLinked to original sources

Donor lymphocyte infusions in adult haploidentical transplant: a dose finding study.

Haploidentical transplantation has become a clinical option for patients lacking a compatible donor. However, patients are still referred at advanced stages and are usually heavily pretreated. This results in a high risk of toxicity, relapses and infections. We therefore started a donor lymphocyte infusion (DLI) dose-finding protocol, to try to improve both relapse rate and immunity reconstitution. In all, 12 consecutive patients were investigated. All had a refractory, some progressive, disease. Conditioning consisted of TBI, melphalan, ATG, fludarabine and CSA pretransplant. In four rapidly progressive patients, Ara-C had to be given 1 week preconditioning. The graft was T- and B-cell depleted with a fixed reinfused CD3 dose of 5 x 10(4)/kg. All patients engrafted before day 20. G-CSF was given from day 5 post-transplant and replaced with GM-CSF in the last three patients. Nonrelapse related mortality was 0/12 at 1 year. DLI were started at day 28 (3 x 10(4) CD3/kg) in the two first patients. This resulted in acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD) in both, but they did not relapse. The next dose was 1 x 10(4)/kg monthly for 3 months. This was well tolerated with only one grade I GVHD. Given the high relapse rate, we escalated doses (1, 3 and 10 x 10(4)/kg). This produced GVHD in all. We next moved, to GM-CSF and 1 x 10(4) CD3/kg monthly. Overall, 6/12 patients relapsed and received therapeutic DLI, starting at 1 x 10(5) CD3/kg with escalation every 2 weeks. We conclude that prophylactic DLI are feasible in adult haploidentical transplantation, without GVHD at a monthly dose of 1 x 10(4) CD3/kg. They result in faster CD4 recovery and a low rate of infections. The impact of GM-CSF remains to be further investigated. This scheme seems ideal for patients transplanted early in the course of their disease. In very bad prognosis patients, it remains insufficient to rapidly induce a GVL effect. Escalated doses are feasible but the price is aGVHD. Therapeutic DLI can be given at higher doses, depending on the time post-transplant. Haploidentical transplantation with low-dose DLI is a safe procedure that should be considered in all patients needing a transplant, but lacking a matched donor, early in the course of the disease.

Adolescent↗

Ex vivo expansion of neutrophil precursor cells from fresh and cryopreserved cord blood cells.

BACKGROUND: Neutropenia following cord blood (CB) transplantation may be abrogated by infusion of granulopoietic progenitor cells. The purpose of this study was to determine whether myeloid progenitors can be obtained by ex vivo expansion of cryopreserved cord blood aliquots, and whether these progenitors present the morphologic, biologic and functional properties of myeloid progenitors at various stages of differentiation. METHODS: The cells, plated for 7 days in serum-free medium with SCF, IL-3, G-CSF, Flt3-ligand and thrombopoietin in various combinations were assessed for the expression of CD34, CD38 and CD13. Maturation of cells into the myeloid lineage was evaluated by the expression of CD15, CD11b and CD16 and by the presence of primary (myeloperoxidase) and secondary granules (lactoferrin). The capacity of cells to phagocyte latex beads was evaluated to assess their functionality. RESULTS: We have shown that a). CD34+ cells isolated from thawed samples were able to produce expansions similar to fresh samples. b). The best combination for the expansion of neutrophil precursor cells was S3FG; c). in these conditions, all stages of myeloid progenitors were represented, but few mature cells were observed. d). However, when the cells were plated on a BM stroma to try to reproduce conditions occurring during transplant, they acquired rapidly the characteristics of mature segmented cells. e). The ex vivo generated granulocytes were able to phagocyte latex beads. DISCUSSION: In conclusion, it seems reasonable to systematically aliquot CB samples before cryopreservation. Some aliquots can then be thawed, enriched in CD34+ cells and ex vivo differentiated into myeloid lineage, while the other aliquots are conserved to be infused without manipulation.

Antigens, CD34↗

Ex vivo myeloid differentiation of cord blood CD34+ cells: comparison of four serum-free media containing bovine or human albumin.

BACKGROUND: Infusion of ex vivo generated myeloid post-progenitor cells associated with unmanipulated cells appears to be a promising approach to reduce neutropenia following cord blood (CB) transplant. We compared four commercially available serum-free media, two containing BSA and two containing human albumin, on the in vitro differentiation of CB CD34+ cells into post-myeloid progenitor cells. METHODS: CB CD34+ cells were cultured for 7 days in CTM-H00 (Mabio-International), StemSpanH2000 (StemCell Technologies), RM-B00 (Mabio-International) and Stem(alpha)A (Stem Alpha). The cells were stimulated by SCF, G-SCF, IL3 and Flt3-ligand (FL) added once at Day 0. Expansion was evaluated as the increase of leucocytes, CD34+ cells and CD13+ cells. Maturation of cells into the myeloid lineage was evaluated by expression of CD15, CD11b and CD16 Ags and by the presence of primary (myeloperoxydase, MPO) and secondary granules (lacoferrin, LF). The capacity of cells to phagocyte latex beads was evaluated to assess their functionality. RESULTS: We observed that: a) the mononuclear cell and CD34+ cell expansions were significantly different according to the medium tested (respectively 61.5 +/- 7.7 and 15.5 +/- 3.4 for RM-B00, 37.3 +/- 5.4 and 10.3 +/- 1.6 for CTM-H00, 23.2 +/- 6.5 and 5.8 +/- 0.9 for StemSpanH2000 and 16.6 +/- 2.4 and 3.9 +/- 0.7 for Stem(alpha)A; b) the expansion of myeloid precursors is higher with RM-B00, similar with CTM-H00 and StemSpanH2000, and lower with Stem(alpha)A. This difference is essentially due to total leucocyte expansion, rather than to a selective expansion of myeloid cells, except for Stem(alpha)A, for which the percentages of neutrophil precursor cells [promyelocytes (CD15+ CD11b+), myelocytes (CD11b+ CD16-) and mature cells (CD11b+ CD16+)] are significantly decreased. DISCUSSION: It appears that during ex vivo differentiation into myeloid lineages, the medium is critical and should be systematically screened before use in preclinical protocols. The use of human rather than bovine albumin, seems to have neither a negative, nor positive impact on the effectiveness of the medium.

Albumins↗

[Hematopoietic stem cells: source, indications and perspectives].

The haematopoietic stem cell (HSC) has been first described in the mouse and now identify in human as well. Exposed to a cocktail of growth factor, this HSC can self re-new and/or differentiate into the three lineages we have in the peripheral blood. These HSC are of major importance in the clinics since they can be used for some marrow (or stem cell) transplantation, and lead to the cure of a number of malignant and non malignant hemopathies. We have today three sources of HSC: the bone marrow, the mobilized peripheral blood stem cell and the cord blood. Bone marrow used to be the classical source of HSC after harvesting by aspirations in the iliac crest. However, this approach is now supplanted by the recovery of HSC in peripheral blood using a cell separation after four days of G-CSF administration. These are several advantages of this technique, but the most important one is the more rapid hematopoietic recovery after transplantation, reducing the risk of infection and transfusion. A recent source of HSC is the umbilical cord blood. At the moment of delivery, the cord blood is extremely enriched in HSC due to the migration of these cells from the liver to the bone marrow stroma, where they will persist after birth. We have learned that the marrow stroma display a major role in the regulation of hematopoiesis and the pathogenesis of several malignant hemopathies can be explained by disturbance in the function of stromal cell. We have particularly studied the patho-genesis of chronic lymphocytic leukaemia. We have also observed that a subpopulation of stromal cells, the mesenchymal cells are of major importance in the microenvironment. In addition, the plasticity of these cells is demonstrated in vitro and we have currently a research program investigating its differentiation in neural cells. All these observations bring new promises in the treatment of hemopathies but also in some other neurological degenerative diseases.

Animals↗

Early induction of apoptosis in B-chronic lymphocytic leukaemia cells by hydroxychloroquine: activation of caspase-3 and no protection by survival factors.

We have investigated the effect of hydroxychloroquine (HCQ), an anti-rheumatic drug, on malignant B cells from 20 patients with B-chronic lymphocytic leukaemia (B-CLL). HCQ induced a decrease in cell viability in a dose- and time-dependent manner. The mean IC50 was 32 +/- 7 microg/ml (range, 10-75 microg/ml) for 24 h of exposure. This cytotoxic effect was owing to apoptosis, as demonstrated by morphological changes, annexin V binding capacity and DNA fragmentation (28 +/- 4% of apoptotic cells as early as 5 h post incubation, increasing to 82 +/- 4% at 18 h post treatment). The apoptosis was associated with caspase-3 activation because the cleavage and activity of caspase-3 were increased by HCQ. The amount of bcl-2 protein was reduced during apoptosis, evidenced using quantitative flow cytometry. As early as 1 h post-HCQ treatment, a reduction of the mitochondrial transmembrane potential was measured by 3,3'-dihexyloxacarbocyanine iodide. Interestingly, the HCQ effect was not affected by exposure to interleukin-4 or co-culture with bone marrow stromal cells. Our observations suggest that HCQ may offer a new therapeutic tool in the treatment of B-CLL patients.

Aged↗

Characterization of CD34+ subsets derived from bone marrow, umbilical cord blood and mobilized peripheral blood after stem cell factor and interleukin 3 stimulation.

We characterized CD34+ cells purified from bone marrow (BM), mobilized peripheral blood (PB) and cord blood (CB) and we tried to establish correlations between the cell cycle kinetics of the CD34+CD38- and CD34+CD38+ subpopulations, their sensitivity to SCF and IL-3 and their expression of receptors for these two CSFs. At day 0, significantly fewer immature CD34+CD38- cells from CB and mobilized PB are in S + G2M phases of the cell cycle (respectively 2.0 +/- 0.4 and 0.9 +/- 0.3%) than their BM counterpart (5.6 +/- 1.2%). A 48-h incubation with SCF + IL-3 allows a significant increase in the percentage of cycling CD34+CD38- cells in CB (19.2 +/- 2.2%, P < 0.0002) and PB (14.1 +/- 5.5%, P < 0.05) while the proliferative potential of BM CD34+CD38- progenitors remains constant (8.6 +/- 1.0%, NS). CD123 (IL-3 receptor) expression is similar in the three sources of hematopoietic cells at day 0 and after 48-h culture. CD117 (SCF receptor) expression, although very heterogeneous according to the subpopulations and the sources of progenitors evaluated, seems not to correlate with the difference of progenitor cell sensitivity to SCF nor with their proliferative capacity. Considering the importance of the c-kit/SCF complex in the adhesion of stem cells to the microenvironment, several observations are relevant. The density of CD117 antigen expression (expressed in terms of mean equivalent soluble fluorescence, MESF) is significantly lower on fresh PB cells than on their BM (P < 0.017) and CB (P < 0.004) counterparts, particularly in the immature CD34+CD38- population (560 +/- 131, 2121 +/- 416 and 1192 +/- 129 MESF respectively); moreover, when PB and BM CD34+CD38- cells are stimulated for 48 h with SCF + IL-3, the CD117 expression decreases by 1.5- and 1.66-fold, respectively. This reduction could modify the functional capacities of ex vivo PB and BM manipulated immature progenitor cells.

Antigens, CD34↗

Adhesion to bone marrow stroma inhibits apoptosis of chronic lymphocytic leukemia cells.

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of monoclonal long-lived B cells which are apparently resistant to normal apoptotic regulation. Since bone marrow stromal cells play an essential role in B lymphopoiesis, we have investigated whether stromal cells influence B-CLL cell survival. Our results indicate that intimate contact with stromal cells reduces B-CLL cell apoptosis and prevents the loss of bcl-2 protein expression. Binding of B-CLL cells to stromal cells requires simultaneous action of beta1 and beta2 integrins. The interaction between B-CLL cells and other cell types seems important for their survival and may represent an important mechanism underlying accumulation of malignant cells in B-CLL patients.

Apoptosis↗

Chronic lymphocytic leukemic B cells but not normal B cells are rescued from apoptosis by contact with normal bone marrow stromal cells.

The leukemic B lymphocytes from chronic lymphocytic leukemic (CLL) patients have a long survival in vivo, although ex vivo they rapidly die by apoptosis. To further investigate the mechanism of this, we have studied the influence of bone marrow stromal cells from normal subjects on apoptosis of B-CLL cells and normal umbilical cord blood (UCB) B lymphocytes. After 48 hours of incubation in medium alone, leukemic and normal B cells showed, respectively, 22 +/- 3% and 31 +/- 5% of apoptosis. Cocultures with stromal cells reduced the percentage of leukemic cells undergoing apoptosis (8 +/- 2%, P < . 0005) and prevented the loss of bcl-2 protein expression. In contrast, stromal cells slightly increased normal B-cell apoptosis (37 +/- 6%). Direct contact between leukemic cells and stromal cells was found to be essential for inhibition of leukemic cell apoptosis; indeed, separation of leukemic cells from stromal cells by microporous membrane increased spontaneous apoptosis, and comparable results were obtained with stromal cell conditioned medium. The difference in behavior observed between normal and leukemic B cells plated on stromal cells can be explained by the fact that only a few normal B cells adhere to stromal cells in comparison with B-CLL cells. B-CLL cell adhesion to stromal cells is mediated by beta1 and beta2 integrins acting simultaneously. Contact between B-CLL cells and bone marrow stromal cells seems to play a major role in the accumulation and survival of B-CLL cells in the bone marrow.

Aged↗

Myeloid and lymphoid recovery following allogeneic bone marrow transplantation: a comparative study between related, unrelated bone marrow and allogeneic peripheral stem cell transplantation.

We studied myeloid and lymphoid recovery during a period of 12 months following HLA matched allogeneic bone marrow transplantation (BMT) in 15 patients. Patients were divided into three groups. Each group contained 5 patients according to the source of hematopoietic stem cell transplantation (HST): 1) related bone marrow transplantation (BMT), 2) allogeneic peripheral blood stem cell transplantation (PBSCT) and 3) matched unrelated donor transplantation (MUD). The rate and pattern of recovery of granulocytes, lymphocytes (T-cell subsets, B-cells, NK cells, subsets of CD45) were studied by cell counting and flow cytometry. Our results suggest faster recovery of PMN after PBSCT. Higher CD4 cell counts observed in the PBSCT group may have an impact on a lower incidence of opportunistic infections. Chronic GvHD mediated GvL effect seems to be more important in blood stem cell transplanted patients and this may have an influence on disease free survival.

Adult↗

TGF-beta activity and expression of its receptors in B-cell chronic lymphocytic leukemia.

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in Western countries and results from the accumulation of B-lymphocytes which are functionally abnormal and predominantly non-cycling in vivo. Consequently, it is important to understand why B-CLL cells accumulate in GO phase. Since TGF-beta is an important negative regulator of the immune system, a loss of responsiveness to this factor might provide a selective advantage to B-CLL cells. Here we review data on the role of TGF-beta in B-CLL. We show that the B-CLL cell response to TGF-beta signals is abnormal in vitro (inhibition of proliferation and induction of apoptosis). This lack of response of B-CLL cells to TGF-beta inhibition appears to be accompanied by a decrease or a loss of TGF-beta receptor expression.

Apoptosis↗

Heterogenous response of B lymphocytes to transforming growth factor-beta in B-cell chronic lymphocytic leukaemia: correlation with the expression of TGF-beta receptors.

We investigated the potential role of transforming growth factor-beta (TGF-beta) on spontaneous and cytokine-induced proliferation of B-cell chronic lymphocytic leukaemia (B-CLL) cells in vitro. Purified B lymphocytes from 21 B-CLL patients were cultured for 5 d in the presence of medium alone, IL-2 and/or IL-10, in the presence or absence of TGF-beta, and proliferation was measured by 3H-thymidine incorporation. TGF-beta inhibited B-cell proliferation in the majority of patients (15/21) but no inhibition was detected in 6/21 patients whatever the type of stimulant used. Addition of neutralizing antibodies to TGF-beta increased spontaneous and cytokine-induced proliferation; this effect was dose dependent and specific because addition of an irrelevant chicken IgG had no effect on B-CLL proliferation. In resistant patients, neutralizing antibodies to TGF-beta did not increase the proliferation. The expression of TGF-beta receptors on B-CLL cells was significantly lower than the one observed on normal CD5+ B lymphocytes for which the sensitivity to TGF-beta inhibition was more marked than in CLL. In addition, we found a strong correlation between the response of leukaemic B cells to TGF-beta inhibitory action and the expression of TGF-beta receptors on these cells. In summary, TGF-beta appears to function in CLL as a negative regulator of B lymphocytes but loss of responsiveness to this factor accompanied by a decrease of TGF-beta receptor expression, might provide a selective advantage to B-CLL lymphocytes.

Aged↗

Ex vivo expansion of CD34 + CD38- cord blood cells.

CD34+ cord blood (CB) cells were expanded in stromal cell-free long-term culture (LTC), in the presence of various combinations of interleukin-3 (IL-3), stem cell factor (SCF), IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and anti-transforming growth factor-beta (anti-TGF-beta) antibody. The progenitor cell expansion was evaluated by monitoring the increase of CD34+ and CD34 + CD38- cells over a period of 21 days. The expansion of immature (B1-CFC, HPP-CFC) and of more committed progenitors (CFU-GM, CFU-GEMM, BFU-E) was also evaluated in specific samples. Our results show that (a) CD34+ cell expansion is highly variable depending on the cord blood samples studied, (b) significant correlations between B1-CFC and CD34 + CD38- and between total CFU and CD34+ cell expansion are observed, (c) SCF in combination with IL-3 appears to expand cell subsets that continue to express their CD34 + CD38- phenotype and that generate both immature and committed progenitors, and (d) the addition of IL-6, GM-CSF, or anti-TGF-beta does not significantly improve these expansions.

ADP-ribosyl Cyclase↗

Human cytomegalovirus increases constitutive production of interleukin-6 and leukemia inhibitory factor by bone marrow stromal cells.

Human cytomegalovirus (CMV) infection is often associated with myelosuppression and acute inflammatory reaction in immunocompromised patients. We have previously documented that CMV exposure of bone marrow (BM) stromal cells reduces the capacity of these cells to support hematopoiesis because of a decreased production of colony-stimulating factors. This study examines the potential role of CMV on constitutive and lipopolysaccharide (LPS)-stimulated production of cytokines involved in inflammatory reaction, interleukin-6 (IL-6) and leukemia inhibitory factor (LIF) by BM stromal cells. The release of IL-6 was already detectable 2 hours post CMV-infection (2.5-fold increase in production) and the cumulative production of IL-6 after 5 days of infection was 23 +/- 1.2 ng/mL (ninefold increase in production). CMV was also able to induce a time-dependent production of LIF that was maximal 8 hours after CMV infection (2.5-fold increase in production). Concomitantly, there was no detectable release of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) by CMV-infected stromal cells. The similar IL-6 and LIF production in the presence of polymyxin B ruled out the possibility that this increase could be caused by contamination of the viral stock by endotoxin. In addition, ultraviolet-inactivated virus behaved similarly to live virus and caused the release of IL-6 and LIF. However, heat-inactivated CMV was unable to induce IL-6 and LIF secretion by BM stromal cells. The production of IL-6 and LIF was also evaluated after stimulation by LPS. After 5 days of CMV exposure, the LPS-stimulated production of IL-6 and LIF was significantly lower than uninfected controls. This LPS-induced release of cytokine production was found to be dependent of viral replication. The experiments have shown that CMV is a potent inducer of IL-6 and LIF with differential effect on constitutive and LPS-stimulated cytokine production by stromal cells; we suggest that CMV induction of IL-6 and LIF during the first hours of infection could play a role in CMV-induced inflammatory reaction. Moreover, our results show that human CMV can disturb the balanced cytokine network involved in the regulation of hematopoiesis.

Bone Marrow Cells↗

Imbalance in production of cytokines by bone marrow stromal cells following cytomegalovirus infection.

The effect of cytomegalovirus (CMV) infection on the production of growth factors and negative regulators in unstimulated or lipopolysaccharide-stimulated human bone marrow stromal cells was assessed. After 5 days, the constitutive and lipopolysaccharide-stimulated production of growth factors was significantly decreased in CMV-infected compared with uninfected stromal cells. This decrease was noted as early as 72 h after infection and appeared to be strictly related to viral replication. On the other hand, the production of inhibitory factors was increased after CMV infection, and this increased release was detectable as early as 24 h after infection. No modulation in the production of interleukin-10 was observed after CMV infection. These data suggest that CMV disturbs the balanced cytokine network, which controls proliferation and differentiation of hematopoietic progenitors. CMV-induced myelosuppression results from this lack of production of growth factors and excess production of inhibitory factors.

Bone Marrow Cells↗

Comparison of the coexpression of CD38, CD33 and HLA-DR antigens on CD34+ purified cells from human cord blood and bone marrow.

Human umbilical cord blood (UCB) cells are currently considered as a potential source of stem cells for transplantation. However, it remains unclear whether a single collection of UCB contains enough progenitors to allow a successful engraftment in adult patients. We were interested in the comparison of the frequency of primitive progenitors in UCB and in human bone marrow (BM). UCB and BM CD34+ cells were purified and compared for their coexpression of CD38, CD33 and HLA-DR. UCB and BM mononuclear fractions were enriched in CD34+ cells using the CEPRATE LC system (CellPro, Bothell, WA). Double-labeling analysis with a flow cytometer showed that 67.9 +/- 7.2% of UCB CD34+ cells are CD38-, while in BM only 10.9 +/- 4.9% of CD34+ are CD38- (p < 0.001). Moreover, our study indicated that a significantly higher percentage of UCB CD34+ is CD33- (97.1 +/- 1.2%) compared to BM (61.8 +/- 8.6%) (p = 0.013). The coexpression of CD34 with HLA-DR was not significantly different in UCB and in BM (respectively, 86.3 +/- 2.7% and 92.7 +/- 5.1%). On the other hand, in vitro assays showed that the number of multipotent (colony-forming units granulocyte-erythroid-macrophage-megakaryocyte [CFU-GEMM]), myeloid (colony-forming units granulocyte-macrophage [CFU-GM]) and erythroid (burst-forming units-erythroid [BFU-E]) progenitors is lower in the CD34+ population from UCB than from BM. In conclusion, in UCB, we have found a significantly higher percentage of CD34+ cells which lacked the expression of CD38 and CD33 antigens suggesting that UCB contains higher proportions of immature progenitor cells (CD34+CD38- and CD34+CD33-) than BM. It seems thus likely that fewer UCB CD34+ cells than BM CD34+ cells would be required for sustained engraftment following transplantation.

Antigens, CD↗

Comparative analysis of cytokines released by bone marrow stromal cells from normal donors and B-cell chronic lymphocytic leukemic patients.

We studied the production of cytokines (G-CSF, GM-CSF, IL-6, LIF and IL-10) by bone marrow stromal cells of five untreated patients with B-CLL, in Rai stage 0, I and II, and of 8 healthy subjects. The production of G-CSF, GM-CSF, LIF and IL-10 did not differ significantly between controls and B-CLL patients. However, the ability of stromal cells to release IL-6 in response to LPS was decreased in all patients: 36 +/- 5 ng/ml versus 123 +/- 47 ng/ml for normal controls (p < 0.004). Moreover, a soluble activity that inhibited hematopoietic colony formation was detected in B-CLL stromal cell conditioned media. Some potential inhibitors were envisaged and the results indicated an increased production of TGF-beta by B-CLL stromal cells compared to normal stromal cells (respectively 53 +/- 10 versus 15 +/- 4 ng/ml, p < 0.03). The reduced capacity of B-CLL stromal cells to produce IL-6 was associated with this excessive release of TGF-beta; indeed, addition of anti-TGF-beta neutralizing antibody to B-CLL stromal cells, before LPS stimulation, totally normalized the production of IL-6. TGF-beta and IL-6 were also measured in serum samples from normal subjects and B-CLL patients. No significant difference was seen in the production of total TGF-beta (bioactive and latent forms) between normal and B-CLL sera but the mean level of bioactive protein in B-CLL sera was increased in comparison with normal sera (1.74 +/- 0.44 versus 0.67 +/- 0.2 ng/ml, p < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗