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Biomedical subjects

A Delforge

Publications and source records attributed to A Delforge.

At least 37 records · Page 2Linked to original sources
PubMed1996

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1994

Modulation of human cord blood progenitor cell growth by recombinant human interleukin 3 (IL-3), IL-6, granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF) in serum-supplemented and serum-free medium.

UNLABELLED: We evaluated the growth of cord blood myeloid progenitors or colony forming units granulocyte-macrophage (CFU-GM) and their response to various recombinant growth factors or colony stimulating factors (CSFs): interleukin 3 (IL-3), IL-6, granulocyte-macrophage CSF (GM-CSF) and stem cell factor (SCF). Using classical stimulant (human placenta conditioned medium or HPCM), we observed a significantly higher day-14/day-7 CFU-GM ratio in CB than in bone marrow (BM). The association of IL-3, IL-6, GM-CSF and SCF induced significantly more CB day-14 CFU-GM than HPCM. This effect is significantly greater in CB than in bone marrow. Since fetal calf serum (FCS) is known to contain inhibitors, we have compared the ability of CSFs to induce CFU-GM formation in FCS-supplemented and FCS-free culture. In CB, using HPCM, we obtained significantly more CFU-GM in FCS-free medium than in FCS-supplemented medium. This difference was corrected by the addition of anti-transforming growth factor-beta (TGF-beta) neutralizing antibody. However, with the association of the four CSFs, no significant difference between FCS and FCS-free culture was observed. IN CONCLUSION: a) day-14/day-7 CFU-GM ratio was higher in CB than in BM indicating that CB CFU-GM are more primitive than BM CFU-GM; b) FCS can be successfully replaced by serum-free medium; c) FCS contains inhibitors of day-14 CFU-GM and among them TGF-beta; and d) the association IL-3, SCF, GM-CSF and IL-6 seems able to totally overcome the inhibitory effect of FCS.

Bone Marrow↗
PubMed1994

Decreased production of cytokines after cytomegalovirus infection of marrow-derived stromal cells.

Cytomegalovirus (CMV) infection is frequently associated with graft failure in bone marrow transplant patients; the pathogenesis of this myelosuppression in not clearly understood. We have previously documented that CMV-induced myelosuppression is related to an alteration of the marrow microenvironment. To further investigate the effect of CMV on stromal cell function, conditioned media (CM) from CMV-infected or uninfected stromal cells were tested for their capacity to promote the growth of granulocyte/macrophage colony-forming cells (CFU-GM) and for their concentration in colony-stimulating factors (CSFs) such as interleukin-3 (IL-3), IL-6, granulocyte-macrophage and granulocyte colony-stimulating factors (GM-CSF and G-CSF). CM from CMV-infected stromal cells failed to sustain granulocyte-macrophage colony-forming unit (CFU-GM) growth. The production of IL-6, GM-CSF, and G-CSF, measured by enzyme-linked immunosorbent assay (ELISA), was 21,150 +/- 3392, 57 +/- 15, and 2340 +/- 717 pg/mL, respectively, in CMV-infected stromal cells stimulated by lipopolysaccharide (LPS) and was significantly decreased (p < 0.01) from the control values (177,138 +/- 98,692, 113 +/- 20, and 5533 +/- 1306 pg/mL). These results suggest that the myelosuppressive effect of CMV is primarily due to a lack of CSF production. To further document this hypothesis, primitive marrow progenitor cells (blast colony-forming cells [Bl-CFC]) cultured on CMV-infected stromal layer have been grown in the presence of IL-3 (20 ng/mL), IL-6 (20 ng/mL), GM-CSF (40 ng/mL), and G-CSF (50 ng/mL). Used alone, all these CSFs partially reverse the CMV-induced inhibition of Bl-CFC growth; the combination of these CSFs completely restores normal Bl-CFC values. These data strongly suggest that CMV-induced myelosuppression is related to the lack of CSF production by the cells of the marrow microenvironment.

Adolescent↗
PubMed1993

Excessive production of transforming growth factor-beta by bone marrow stromal cells in B-cell chronic lymphocytic leukemia inhibits growth of hematopoietic precursors and interleukin-6 production.

To explore the pathogenesis of marrow failure in B-cell type chronic lymphocytic leukemia (B-CLL), we have examined the production of interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage CSF (GM-CSF) by the adherent cell population of bone marrow (BM) derived from B-CLL patients and their capacity to support hematopoietic cell proliferation. Lipopolysaccharide-stimulated B-CLL stromal cells produced G-CSF and GM-CSF in amounts similar to normal stromal layers, whereas IL-6 production was significantly decreased. Using the blast-colony forming cell assay (BI-CFC) and the classical colony-forming unit granulocyte macrophage (CFU-GM) assay, we found that: (1) marrow stromal cells of B-CLL were able to support only 25% of the BI-CFC growth supported by normal marrow stromal cells; (2) this anomaly was partially corrected by the addition of exogenous IL-6; (3) the colony-stimulating activity (CSA) of the conditioned medium (CM) of B-CLL stromal cells was lower than that of normal CM; (4) that this was the result of the presence of an inhibitor rather that of a growth factor defect; (5) this inhibition could be abrogated by addition of anti-transforming growth factor-beta (TGF-beta) neutralizing antibody; (6) this antibody corrected the deficient colony supportive activity of the B-CLL stromal cells; (7) TGF-beta production by marrow stromal cells was significantly increased in CLL compared with normal; and (8) that this was not caused by the effect of the B-CLL lymphocytes on the stromal cells. It is concluded that this increased TGF-beta production in B-CLL is probably responsible for the decreased IL-6 production by stromal cells and for the inhibiting activity on hematopoietic precursors as well. We hypothesize that TGF-beta generated at a high level by B-CLL marrow stromal cells could play a major role in the pathophysiology of the BM failure seen in advanced stages of B-CLL.

Aged↗
PubMed1993

Modulation of the growth of hematopoietic human stem cells by growth factors: comparison of umbilical cord blood with bone marrow.

The growth of cord blood and bone marrow myeloid mononuclear cells in response to single and multiple growth factors has been examined. Single factors such as IL-3, IL-6, GM-CSF, and stem cell factor did not optimally stimulate growth of cord blood CFU-GM. However a synergistic stimulation was observed when the factors were combined. This effect was seen in both the presence and absence of added fetal calf serum.

Antigens, CD↗
PubMed1991

Prevention of CMV-induced myelosuppression by anti-CMV antibodies: an in vitro model.

Pathogenesis of cytomegalovirus (CMV)-induced myelosuppression is not clearly understood and could be related to a direct toxic effect on the marrow progenitors and/or an alteration of the marrow environment. Myeloid progenitors (granulocyte-macrophage colony-forming units, CFU-GM) were not affected by incubation with increasing titers of CMV (10-10(5) plaque-forming units [pfu]/ml) during 2-6 h. By contrast, using the blast colony-forming cell (Bl-CFC) assay, we confirmed that CMV induced myelosuppression through an alteration of the marrow-derived stromal layer. Using this experimental model, we compared the capacity of nonspecific human immunoglobulins (IgG), specific polyclonal anti-CMV IgG, and a human monoclonal anti-CMV IgG to prevent the myelosuppressive effect of 10(4) pfu/ml of CMV. Specific anti-CMV IgG (polyclonal or monoclonal) at the concentration of 10 micrograms/ml were able to prevent the CMV-induced myelosuppressive effect, whereas nonspecific human IgG was not effective in this model. Our results suggest that 1) CMV-induced myelosuppression is related to an alteration of the marrow microenvironment, 2) specific monoclonal and polyclonal anti-CMV IgG prevent this myelosuppressive effect in vitro, and 3) human monoclonal anti-CMV IgG could be useful in vivo in the immunoprophylaxis of CMV infections.

Antibodies, Monoclonal↗
PubMed1990

Analysis of interferon-inducible genes in cells of chronic myeloid leukemia patients responsive or resistant to an interferon-alpha treatment.

Recombinant human interferon-alpha (IFN-alpha) can induce a hematologic remission in patients with chronic myeloid leukemia. However, some patients are resistant and others develop late resistance to the IFN-alpha treatment. To understand the molecular mechanism of this resistance, we have analyzed the expression of 10 IFN-inducible genes in the cells of three resistant patients, two responsive patients, and six healthy controls. Northern blot hybridizations showed that all the genes were induced in in vitro IFN-alpha treated peripheral blood cells of the patients and healthy controls. These genes were also inducible in peripheral blood and bone marrow cells of two out of two resistant patients administered an injection of IFN-alpha. We conclude that the resistance to the IFN-alpha treatment of the chronic myeloid leukemia patients we studied is not due to (1) the absence of induction of any of the 10 IFN-inducible genes we studied, including the low-molecular-weight 2'-5'oligoadenylate synthetase; (2) the presence of an antagonist of IFN-alpha in the peripheral blood or bone marrow cells; and (3) the presence of neutralizing anti-IFN-alpha antibodies.

2',5'-Oligoadenylate Synthetase↗
PubMed1990

Production of human monoclonal IgG antibodies reacting with cytomegalovirus (CMV).

A human monoclonal antibody (MoAb) reacting with cytomegalovirus (CMV) has been produced using somatic cell hybridization between Epstein-Barr virus (EBV) infected B lymphocytes and a human-mouse heteromyeloma cell line (SHM-D33). The hybrids were selected in HAT medium containing 5 x 10(-7) ouabain. The median level of Ig production was 5 (0.1-20) micrograms/10(6) cells/day. One selected hybridoma (IB-8E9H5) has been maintained in continuous culture for more than 30 months with a stable IgG2, lambda production. Molecular hybridization using EBV-specific probes demonstrate that our hybrids have lost the IR-1 EBV sequence during fusion. Unexpectedly, these blotting experiments revealed the presence of multiple EBNA-1 sequences dispersed among the genomic DNA of the SHM-D33 cell line. Screening for anti-CMV specificity was performed by ELISA and confirmed by immunofluorescence staining. Thus far, three CMV reference strains and 14 local strains are stained by the MoAb as early as 3 h after CMV infection of human fibroblasts, apparently through the recognition of a nuclear viral antigen of 67 kDa. In conclusion, this technique permits (a) the removal of the EBV genome contained in the lymphoblastoid parental cell line and (b) the production of human anti-CMV MoAb with potential applications in the prevention of life threatening CMV infections.

Antibodies, Monoclonal↗
PubMed1990

Inhibitory effects of potent inhibitors of human immunodeficiency virus and cytomegalovirus on the growth of human granulocyte-macrophage progenitor cells in vitro.

Phosphonoformate, ganciclovir, zidovudine and the novel acyclic nucleotide analogues (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA] and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine [(S)-HPMPC] were evaluated for their inhibitory effect on colony forming unit formation by human granulocyte-macrophage progenitor cells (obtained from 11 healthy volunteers) in vitro. The 50% inhibitory dose of zidovudine, (S)-HPMPA, (S)-HPMPC, ganciclovir and phosphonoformate were 10.61, 16.55, 80.88, 41.02 and 668.64 microM, respectively, when the median-effect principle was applied. The bone marrow toxicity of zidovudine used at a low concentration (3.74 microM) was significantly decreased if the drug was combined with (S)-HPMPA, (S)-HPMPC or ganciclovir. If used at higher concentrations (74.90 microM), zidovudine showed increased myelotoxicity in the presence of (S)-HPMPA and ganciclovir, but not (S)-HPMPC.

Adenine↗
PubMed1990

Influence of recombinant alpha and gamma interferons on the in vitro proliferation of myeloid and leukemic progenitors.

We have compared the effect of alpha 2-C and gamma recombinant interferons (rIFNs) on normal myeloid progenitors (N-CFU-GM), chronic myeloid leukemia (CML) progenitors (CML-CFU-GM) and leukemic progenitors (L-CFU) of acute non-lymphoblastic leukemia (ANLL) patients. Within 14 days of continuous exposure in culture, a dose-dependent inhibition of CFU-GM was seen for most normal subjects. Resistance to rIFNs was frequent in leukemic patients and even more in acute leukemia than in CML. Stimulation of clonogenic cell growth was seen for a minority of leukemic patients. When only the sensitive cases were considered, no difference in sensitivity was noticed between normal, CML and ANLL patients. A good correlation was observed between the activity or the lack of activity of alpha and gamma rIFNs.

Bone Marrow↗
PubMed1989

[Adoptive immunotherapy with interleukin 2. Initial results of a pilot study in 6 cancer patients].

Adoptive immunotherapy of cancer consists of using interleukin-2 to induce the formation of lymphokine-activated killer (LAK) cells which are toxic to tumoral cells. Six patients, 3 with hypernephroma and 3 with melanoma, were treated with interleukin-2. Drug toxicity consisted of capillary leakage syndrome in one case and reversible renal impairment in another. One patient showed an objective response; transient subjective improvement was observed in all patients.

Acute Kidney Injury↗
PubMed1989

Tolerance and effectiveness of recombinant interleukin-2 (r-met Hu IL-2 [ala-125]) and lymphokine-activated killer cells in patients with metastatic solid tumors.

The tolerance of a recombinant human interleukin-2 (rIL-2, r-met Hu IL-2 [ala-125], Ortho Pharmaceutical) and its antitumor effectiveness in combination with lymphokineactivated killer (LAK) cells was examined in 26 patients with metastatic solid tumors, including 14 renal cell carcinomas, seven melanomas, three extragonadal germ cell tumors refractory to chemotherapy and two colon carcinomas. rIL-2 was administered as a bolus at 30,000 U/kg every 8 h on days 1-5 and days 12-19. Leukapheresis was done on days 8-12, lymphocytes were incubated with rIL-2 for 3 or 4 days in vitro and reinfused on days 12, 13 and 15. The mean number of reinfused cells was 5.1 x 10(10) per patient. IL-2 dose and schedule were adjusted according to toxicity. Patients received a median of 100% (range 87-100%) of planned rIL-2 on days 1-5 and a median of 71% (range 13-100%) on days 12-19. Capillary leak syndrome with hypotension and impaired renal function and CNS toxicity were the major reasons for dose modification. Patients with renal cell carcinoma, most of whom underwent a prior nephrectomy, had a reduced tolerance to rIL-2. Partial responses were documented in three renal cell carcinomas and one melanoma. The median response duration was 5.5 (range 1-6) months.

Adult↗
PubMed1989

Comparison of in vitro inhibition of etoposide (VP16) on leukemic and normal myeloid, erythroid clonogenic cells.

We have compared in various clonogenic assays the in vitro sensitivity to etoposide (VP16) of 1) human leukemic precursors (leukemia colony-forming units; L-CFU), 2) normal erythroid progenitors (erythroid burst-forming units; BFU-E, and 3) normal committed myeloid progenitors (granulocyte-macrophage colony-forming units; CFU-GM and more primitive hemopoietic precursors (PPC) that adhere to cultured marrow stromal cells. Bone marrow samples were obtained from 15 normal subjects and 16 leukemic patients: 9 in the acute phase of acute nonlymphoblastic leukemia (ANLL) and 7 in complete remission. VP16 was tested at concentrations ranging from 10(-8) to 10(-3) M. The median recoveries at 10(-3) M VP16 were respectively 0%, 0.5%, 0%, and 0% for leukemic progenitors, CFU-GM from leukemic patients in complete remission, normal CFU-GM, and BFU-E, and 23% for PPC. This indicates that CFU-GM, BFU-E, and L-CFU are highly sensitive to VP16, whereas PPC, more primitive myeloid precursors, are spared. These results suggest that VP16 may be used as an "ex vivo" purging agent for autologous bone marrow.

Cell Survival↗