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Yves Beguin

Publications and source records attributed to Yves Beguin.

At least 37 records · Page 2Linked to original sources
PubMed2004

Impact of erythropoietic activity on red cell parameters in chronic renal failure patients.

We measured red cell parameters during recombinant human erythropoietin (rHuEPO) therapy associated with appropriate iron supplementation in chronic hemodialysis patients. Increased erythropoietic activity led to a bias in red cell parameter determination. The percentage of hypochromic red blood cells, usually used as the most effective predictor of response to iron supplementation, increased following the appearance of a younger red cell population since the same Hb content in these younger, larger cells gives a lower Hb concentration.

Erythrocyte Indices↗
PubMed2003

T-cell reconstitution after unmanipulated, CD8-depleted or CD34-selected nonmyeloablative peripheral blood stem-cell transplantation.

BACKGROUND: We have previously shown that CD8 depletion or CD34 selection of peripheral blood stem cells (PBSC) reduced the incidence of acute graft-versus-host disease (GvHD) after nonmyeloablative stem-cell transplantation (NMSCT). In this study, we analyze the effect of CD8 depletion or CD34 selection of the graft on early T-cell reconstitution. METHODS: Nonmyeloablative conditioning regimen consisted in 2 Gy total-body irradiation (TBI) alone, 2 Gy TBI and fludarabine, or cyclophosphamide and fludarabine. Patients 1 to 18 received unmanipulated PBSC, patients 19 to 29 CD8-depleted PBSC, and patients 30 to 35 CD34-selected PBSC. RESULTS: T-cell counts, and particularly CD4+ and CD4CD45RA+ counts, remained low the first 6 months after nonmyeloablative stem-cell transplantation (NMSCT) in all patients. CD34 selection (P<0.0001) but not CD8 depletion of PBSC significantly decreased T-cell chimerism. Donor T-cell count was similar in unmanipulated compared with CD8-depleted PBSC recipients but was significantly lower in CD34-selected PBSC recipients (P=0.0012). T cells of recipient origin remained stable over time in unmanipulated and CD8-depleted PBSC patients but expanded in some CD34-selected PBSC recipients between day 28 and 100 after transplant. Moreover, whereas CD8 depletion only decreased CD8+ counts (P<0.047), CD34 selection reduced CD3+(P<0.001), CD8+(P<0.016), CD4+ (P<0.001), and CD4+CD45RA+ (P<0.001) cell counts. T-cell repertoire was restricted in all patients on day 100 after hematopoietic stem-cell transplantation but was even more limited after CD34 selection (P=0.002). CONCLUSIONS: Despite of the persistence of a significant number of T cells of recipient origin, T-cell counts were low the first 6 months after NMSCT. Moreover, contrary with CD8 depletion of the graft that only affects CD8+ lymphocyte counts, CD34 selection dramatically decreased both CD8 and CD4 counts.

Adult↗
PubMed2003

Recombinant human erythropoietin therapy is very effective after an autologous peripheral blood stem cell transplant when started soon after engraftment.

PURPOSE: Previous trials of recombinant human erythropoietin (rHuEpo) therapy after autologous hematopoietic stem cell transplantation have administered very high doses of i.v. rHuEpo starting on day 1 and continuing for 1-2 months until erythroid engraftment and have shown no benefit of rHuEpo therapy. We sought to establish a more effective use of rHuEpo in this setting. EXPERIMENTAL DESIGN: In this report, we show in a first cohort of 45 lymphoma or myeloma patients undergoing peripheral blood stem cell transplant (control group) that endogenous erythropoietin levels are high for the degree of anemia during the first 3 weeks after transplant but become adequate or slightly decreased thereafter. We thus enrolled 41 consecutive similar patients in a trial of rHuEpo therapy at a dose of 500 units/kg/week started on day 30 after the transplant. RESULTS: The 12-week probability of achieving hemoglobin (Hb) levels of 13 g/dl was 87% in rHuEpo-treated patients versus 14% in controls (P = 0.0001). Mean Hb levels were significantly higher in the rHuEpo group than in the control group from day 42 through day 150 after transplant (Ps of <0.05 to <0.001). Two of 41 patients in the rHuEpo group versus 12 of 45 patients in the control group had Hb levels of <9 g/dl between day 42 and day 100 after the transplant (P = 0.0078). CONCLUSIONS: Anemia after autologous peripheral blood stem cell transplant is exquisitely sensitive to rHuEpo when therapy is started soon after engraftment. This is the first convincing report showing that rHuEpo is effective in this setting. Our data set the stage for a more rational use of rHuEpo after autologous hematopoietic stem cell transplantation and should renew interest in erythropoietin therapy in this setting. Prospective, randomized trials should investigate the impact of rHuEpo therapy on transfusion requirements and quality of life.

Adolescent↗
PubMed2003

Soluble transferrin receptor for the evaluation of erythropoiesis and iron status.

Iron transport in the plasma is carried out by transferrin, which donates iron to cells through its interaction with a specific membrane receptor, the transferrin receptor (TfR). A soluble form of the TfR (sTfR) has been identified in animal and human serum. Soluble TfR is a truncated monomer of tissue receptor, lacking its first 100 amino acids, which circulates in the form of a complex of transferrin and its receptor. The erythroblasts rather than reticulocytes are the main source of serum sTfR. Serum sTfR levels average 5.0+/-1.0 mg/l in normal subjects but the various commercial assays give disparate values because of the lack of an international standard. The most important determinant of sTfR levels appears to be marrow erythropoietic activity which can cause variations up to 8 times below and up to 20 times above average normal values. Soluble TfR levels are decreased in situations characterized by diminished erythropoietic activity, and are increased when erythropoiesis is stimulated by hemolysis or ineffective erythropoiesis. Measurements of sTfR are very helpful to investigate the pathophysiology of anemia, quantitatively evaluating the absolute rate of erythropoiesis and the adequacy of marrow proliferative capacity for any given degree of anemia, and to monitor the erythropoietic response to various forms of therapy, in particular allowing to predict response early when changes in hemoglobin are not yet apparent. Iron status also influences sTfR levels, which are considerably elevated in iron deficiency anemia but remain normal in the anemia of inflammation, and thus may be of considerable help in the differential diagnosis of microcytic anemia. This is particularly useful to identify concomitant iron deficiency in a patient with inflammation because ferritin values are then generally normal. Elevated sTfR levels are also the characteristic feature of functional iron deficiency, a situation defined by tissue iron deficiency despite adequate iron stores. The sTfR/ferritin ratio can thus describe iron availability over a wide range of iron stores. With the exception of chronic lymphocytic leukemia (CLL) and high-grade non-Hodgkin's lymphoma and possibly hepatocellular carcinoma, sTfR levels are not increased in patients with malignancies. We conclude that soluble TfR represents a valuable quantitative assay of marrow erythropoietic activity as well as a marker of tissue iron deficiency.

Animals↗
PubMed2003

Once-weekly epoetin beta is highly effective in treating anaemic patients with lymphoproliferative malignancy and defective endogenous erythropoietin production.

Epoetin beta, three-times weekly (t.i.w.), is effective in reversing anaemia in lymphoproliferative disorders. The current study investigated whether an epoetin beta dose of 30,000 IU given subcutaneously once weekly (q.w.) was at least as effective as 10,000 t.i.w. administration in anaemic patients with lymphoproliferative malignancy and defective endogenous erythropoietin (Epo) production. Overall, 241 anaemic patients with multiple myeloma, low-grade non-Hodgkin's lymphoma or chronic lymphocytic leukaemia, all with serum Epo values </= 100 mU/ml, were randomized to receive the q.w. (n = 119) or t.i.w. (n = 122) regimen for 16 weeks. The primary efficacy criterion, i.e. the time-adjusted area under the haemoglobin-time curve from weeks 5-16, was comparable between the q.w. and t.i.w. groups [difference = - 0.20 g/dl (90% confidence interval - 0.52-0.11)]. Moreover, response rates were high and similar in both arms (72%vs 75%, q.w. and t.i.w. groups respectively). Baseline serum Epo was predictive of response: the lower serum Epo, the higher the likelihood of response (P = 0.002). Thus, epoetin beta administered q.w. is an effective and convenient treatment for anaemia in patients with lymphoproliferative disorders. Tailoring this treatment modality to subjects with defective endogenous Epo production represents a rational use of epoetin from both a medical and a community perspective.

Adult↗
PubMed2003

Tandem high-dose therapy (HDT) for multiple myeloma: recombinant human erythropoietin therapy given between first and second HDT allows second peripheral blood stem cell transplantation without red blood cell transfusion.

We evaluated the ability of recombinant human erythropoietin (rHuEpo) therapy, given before high-dose therapy (HDT), to allow autologous peripheral blood stem cell transplantation (PBSCT) without red blood cell (RBC) transfusions. Eleven multiple myeloma patients underwent tandem HDT and autologous PBSC, receiving 500 U/kg/week rHuEpo from d 30 after initial transplant. Haemoglobin levels were 9.5 +/- 1.1 g/dl and 12.5 +/- 0.9 g/dl at the first and second transplant respectively (P < 0.001). RBC transfusions were required for 10/11 patients for the first transplant versus 1/11 for the second (P < 0.001). To conclude, a short course of rHuEpo therapy before HDT facilitates the performance of an autologous transplant without RBC transfusions.

Adult↗
PubMed2003

Phase III randomized study comparing 5 or 10 microg per kg per day of filgrastim for mobilization of peripheral blood progenitor cells with chemotherapy, followed by intensification and autologous transplantation in patients with nonmyeloid malignancies.

BACKGROUND: It is not known whether increasing the dose of filgrastim after mobilizing chemotherapy improves collection of peripheral blood progenitor cells (PBPC) and leads to faster hematopoietic engraftment after autologous transplantation. STUDY DESIGN AND METHODS: A randomized, open-label, multicenter trial was carried out in patients with breast cancer, multiple myeloma, and lymphoma, in which patients were randomized to receive 5 or 10 microg per kg per day of filgrastim after standard chemotherapy to mobilize PBPCs. After high-dose chemotherapy, the components from the first two leukapheresis procedures were returned, and all patients received 5 microg per kg day of filgrastim after transplantation. RESULTS: A total of 131 patients were randomized, of whom 128 were mobilized (Group A, 5 microg/kg, n = 66; Group B, 10 microg/kg, n = 62) and 112 were transplanted. Only six patients were not transplanted because of insufficient CD34+ cell numbers. The median number of CD34+ cells collected in the first two leukapheresis procedures tended to be higher in Group B than in Group A (12.0 vs. 7.2 x 10(6)/kg, NS), but after transplantation there was no significant difference in median times to platelet (9 days in both groups) or neutrophil (8 days in both groups) engraftment or the number of platelet transfusions (three in both groups). A subsequent subgroup analysis separating patients transplanted after first- or second-line chemotherapy also showed no measurable impact of filgrastim dose on the median CD34+ cell yield or on platelet engraftment in either subgroup. CONCLUSION: PBPC mobilization with chemotherapy and 5 microg per kg of filgrastim is very efficient, and 10 microg per kg of filgrastim does not provide additional clinical benefit.

Adult↗
PubMed2003

Binding and migration across fibronectin and VCAM-1 of cycling hematopoietic progenitor cells.

Using different experimental approaches, it has been established that transplantability of hematopoietic/stem progenitor cells is ineffective during transit through the cell cycle. Although primitive stem cells are responsive to mitogenic stimulation in optimized ex vivo conditions, defective engraftment of generated cells may limit their detection in standard transplantation models as well as their use in clinical cell therapy. The activation level of adhesion receptors is modulated by stimulation of cytokine receptors via "inside-out" signaling. This prompted us to study the interactions of progenitor cells with fibronectin (Fn) in different phases of the cell cycle. We first demonstrated that adhesion to Fn was stimulated in S/G2 + M as compared to G0/G1, in ex vivo cultured CD34+ cells, with a predominant usage of very late antigen (VLA)-5 over that of VLA-4. We next determined that maximal Fn binding in active phases of the cell cycle limited cell motility toward stromal cell-conditioned medium. It was also observed that VLA-4 and VLA-5 ability to mediate adhesion or migration varied independently during cell cycle transit. Finally, in synchronized progenitor cells executing a first cell cycle ex vivo, a reversible increase in Fn binding was associated with a reversible decrease in adhesion to vascular cell-adhesion molecule (VCAM)-1. Overall, these observations suggest that defective engraftment of cycling stem/progenitor cells may result, at least in part, from abnormal trafficking related to changes in the activation level of adhesion receptors.

Animals↗
PubMed2003

Long-term disease-free survival in patients with angioimmunoblastic T-cell lymphoma after high-dose chemotherapy and autologous stem cell transplantation.

BACKGROUND AND OBJECTIVES: Patients with angioimmunoblastic T-cell lymphoma (AIL) have a poor prognosis with conventional treatment. DESIGN AND METHODS: We initiated an EBMT-based survey studying the impact of high-dose chemotherapy (HDCT) and autologous hematopoietic stem cell transplantation in patients with AIL. Data on 29 patients, who were transplanted between 1992 and 1998 in 16 transplant centers, were collected on standardized documentation forms. RESULTS: The median age at transplantation was 53 years. HDCT was given as part of 1st-line therapy (N=14; 48%) or 2nd/3rd-line therapy (N=15; 52%). Regimens for the mobilization of peripheral blood stem cells (PBSC) included VIPE (N=7; 26%), DexaBEAM (N=6; 22%), CHOP-like regimens (N=6; 22%), other regimens (N=5; 19%) or alternatively growth factor alone (N=3; 11%). The median yield of PBSC was 3.8x106 CD34+cells/kg. Two patients received autologous bone marrow. The HDCT consisted of BEAM-type regimens in 16 patients, ICE-type regimens in 7, and other regimens in 6 patients. There was one treatment-related death. The rate of complete remissions increased from 45% before HDCT to 76% after HDCT. As of January 2003, after a median observation time of living patients of 5 years (range 2.5 to 10 years), 14 patients have died (13 from progressive disease), and 15 patients are alive. The probability of 5-year overall and event-free survival was 44% (95% CI, 22% to 66%) and 37% (95% CI, 17% to 57%), respectively. Long-term disease-free survival was observed in patients transplanted during 1st-line treatment as well as in the context of 2nd/3rd-line therapy. INTERPRETATION AND CONCLUSIONS: There is evidence that AIL is susceptible to high-dose chemotherapy. HDCT and autologous stem cell transplantation should be considered in selected patients with AIL.

Adult↗
PubMed2002

Adhesion of synchronized human hematopoietic progenitor cells to fibronectin and vascular cell adhesion molecule-1 fluctuates reversibly during cell cycle transit in ex vivo culture.

Ex vivo expansion of hematopoietic stem/progenitor cells may result in defective engraftment. Human cord blood CD34(+) progenitor cells were synchronized and assayed for adhesion and migration onto fibronectin (Fn) and vascular cell adhesion molecule-1 (VCAM-1) at different stages of a first cell cycle executed ex vivo. During S phase transit, adhesion to Fn was transiently increased while binding to VCAM-1 was reversibly decreased, after which adhesion to both ligands returned to baseline levels with cell cycle completion. Transmigration across Fn and VCAM-1 decreased irreversibly during S phase progression. The function of alpha4 and alpha5 integrins was assessed with specific neutralizing antibodies. In uncultured CD34(+) cells and long-term culture-initiating cells (LTC-ICs), both adhesion and migration on Fn were inhibited by anti-alpha4 but not by anti-alpha5 antibodies. In mitotically activated CD34(+) cells and LTC-ICs, adhesion and migration on Fn were mainly dependent on alpha5 integrin and to a lesser extent on alpha4 integrin. Changes in integrin function were not dependent on parallel modulation of integrin expression. In conclusion, Fn and VCAM-1 binding of progenitor cells fluctuates reversibly during cell cycle transit ex vivo. In addition, our data show that mitogenic activation induces a shift from a dominant alpha4 to a preferential alpha5 integrin-dependent interaction with Fn.

Antigens, CD↗
PubMed2002

Increased binding and defective migration across fibronectin of cycling hematopoietic progenitor cells.

Engraftment of hematopoietic progenitor cells has been shown to decrease during cell cycle transit. We studied cell cycle-associated changes in adhesion and migration of mitotically activated cord blood CD34+ cells. Migration toward medium conditioned by the stromal-derived factor-1-producing cell line MS-5 was studied in bovine serum albumin- and fibronectin (Fn)-coated transwells. Migration was reduced in cycling CD34+ cells and long-term culture-initiating cells (LTC-ICs) compared with their noncycling counterparts across Fn but not across bovine serum albumin. Conversely, Fn binding was higher in cycling CD34+ cells and LTC-ICs compared with noncycling progenitor cells, while adhesion of both subsets to bovine serum albumin was undetectable. The contribution of alpha4 and alpha5 integrins in mediating adhesion and migration of activated CD34+ cells onto Fn was analyzed by neutralization experiments. While alpha4-mediated Fn binding decreased during G(2)/M, alpha5 integrin-mediated adhesion increased during transit from G(0)/G(1) to S and G(2)/M phases. As for migration, the contribution of alpha4 integrin was similar in all phases, whereas alpha5-directed migration was lower in G(2)/M compared with G(0)/G(1) and S phases. Defective migration of cycling CD34+ cells was not due to differences in alpha5 integrin expression. In conclusion, chemotaxis across Fn is less efficient in cycling progenitor cells in correlation with an increased Fn binding capacity. In addition, alpha4 and alpha5 integrin functions are independently modulated during cell cycle transit.

Antigens, CD↗
PubMed2002

Optimization of recombinant human erythropoietin therapy after allogeneic hematopoietic stem cell transplantation.

OBJECTIVE: Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with prolonged anemia caused by defective erythropoietin (Epo) production. We enrolled 34 recipients of an allogeneic HSCT in three consecutive trials to determine the optimal utilization of recombinant human erythropoietin (rhEpo) therapy in this setting. MATERIALS AND METHODS: In the first trial (n = 7), rhEpo 1400 U/kg/week was given from day 1 until a hemoglobin (Hb) level of 10 g/dL was achieved, for a maximum of 60 days. In the second trial, rhEpo 500 U/kg/week was given to achieve Hb levels of 13 to 14 g/dL in 13 anemic patients with fatigue 56 to 1440 days after transplant. In the third trial, rhEpo was scheduled to start on day 35 in 14 patients at a dose of 500 U/kg/week with the aim of achieving Hb levels of 13 to 14 g/dL. RESULTS: In trial 1, erythroid recovery to 1% reticulocytes and red blood cell transfusion independence were faster, but the number of transfusions was not reduced compared to 10 controls. Responses were brisk in trial 2, with transfusion independence achieved after a median of 1 week in 12 of 13 patients, and 2-g Hb increments or Hb values of 11, 12, and 13 g/dL after 6, 7, 10, and 10 weeks, respectively. Transfusions were significantly reduced in the first month of rhEpo therapy. In trial 3, transfusion independence was obtained after a median of 1 week in 13 of 14 patients, and 2-g Hb increments or Hb values of 11, 12, and 13 g/dL after 3, 4, 6, and 8 weeks, respectively. Transfusions rates were considerably reduced compared to the previous month in the same patients or compared to controls undergoing peripheral blood or marrow transplant without rhEpo. CONCLUSIONS: Anemia after allogeneic HSCT is exquisitely sensitive to rhEpo. The benefit is minimal when it is given early post-transplant, as used in all trials to date. However, the rate of major response is greater than 90% when rhEpo is started after day 35. These data provide the basis on which to conduct a prospective, randomized, placebo-controlled trial of rhEpo therapy after allogeneic HSCT.

Adolescent↗