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P Hénon

Publications and source records attributed to P Hénon.

15 recordsLinked to original sources
PubMed2003

CD34+ cells and CD34+CD38- subset from mobilized blood show different patterns of adhesion molecules compared to those from steady-state blood, bone marrow, and cord blood.

As suggested previously, a down-regulation of some cellular adhesion molecules (CAMs) on CD34(+) hematopoietic progenitor cells (HPC) may contribute to their egress from bone marrow (BM) to peripheral blood (PB) by decreasing their adhesion to BM stromal cells. Besides counting the percentage of CAM-positive cells, we decided to define clearly the antigen density (AgD) of the CAM on mobilized- and steady-state CD34(+) HPC using QIFIKIT calibration beads. Five sources of cells were compared: PB and BM from normal donors (nPB, nBM) cord blood (CB), mobilized PB obtained from leukapheresis products (LKP), and mobilized BM (mBM) samples. In our study the CAM-AgD was the lowest on CD34(+) cells in LKP which, on the contrary, contained the highest percentage of CD117(+), CD54(+), CD58(+) cell subsets. As for CB, a greater proportion of CD44(+) and CD62L(+) cells was observed in LKP than in other products. The LKP-CD34(+) cell population contained a greater percentage of CD11a(+) cells when compared to mBM, but the lowest percentage of CD49d(+) and CD49e(+) cells when compared to all products. The proportion of the CD34(+)CD38(-) immature subset expressing CD11a, CD44, CD54, or CD62L was greater in LKP than in mBM; the CD62L-AgD was higher in LKP than in mBM. This quantitative analysis clearly showed a downregulation of all CAM on LKP-CD34(+). The CD44, CD62L, CD11a, and CD54 AgD decrease appears to be specifically involved in the egress of the CD34(+) subsets into PB. The control of antigen density of these adhesion molecules is likely to be clinically important for effective mobilization of HPC as well as for rapid engraftment following HPC transplant.

ADP-ribosyl Cyclase↗
PubMed2000

Human accessory cells have a humoral bystander effect on CAFC growing on murine feeder.

Human early hematopoietic progenitors from bone marrow (BM) and leukapheresis products (LP) are highly proliferative in presence of accessory cells in standard culture on the murine FBMD-1 cell feeder with weekly addition of human interleukin-3 (HuIL-3) and granulocyte-colony stimulating factor (HuG-CSF). If however purified CD34+ cells are cultured under otherwise identical conditions, cobblestone areas (CAFC) formed by the same number of target cells are diminished by more than 1 log, as we showed previously. This suggests that mature cells are involved in growth of early progenitors. To determine whether this bystander effect is mediated by soluble growth factors, or by direct cell-to-cell contact with early progenitors, we stimulated mature plastic adherent cells separately and tested the resulting conditioned supernatant (ACS) on CAFC and colony-forming unit-granulocyte-macrophage (CFU-GM) production. In ACS-complemented standard cultures of purified CD34+ cells, the yield of CAFC was up to 1 log higher if compared to parallel cultures without ACS. Likewise, the CFU-GM production was enhanced in presence of ACS, especially in the adherent fraction of the culture. When CD34+ cell cultures were performed with ACS but without added interleukin-3 (IL-3) and granulocyte colony-stimulating factor (G-CSF), CAFC production was in the same range as if these growth factors were added alone. Addition of anti-G-CSF antibody (Ab) to ACS decreased CAFC recruitment significantly, whereas anti-IL-3 Ab had no significant effect. These findings suggest that ACS complemented with IL-3 and G-CSF replaces the accessory cells largely; this is not only due to presence of G-CSF, because ACS in combination with recombinant growth factors mounts CAFC yield higher than saturating amounts of growth factors alone do. There must be further synergizing soluble factors in the supernatant.

Animals↗
PubMed1998

Mature accessory cells influence long-term growth of human hematopoietic progenitors on a murine stromal cell feeder layer.

A recently described long-term culture system for early human progenitor cells was established with the murine preadipocyte stromal line FBMD-1 grown in 96-well plates; cobblestone areas formed by inoculated hematopoietic cells are determined in a limiting dilution setting after five weeks' culture. To compare the capacity of cobblestone-area-forming cell (CAFC) formation by bone marrow and leukapheresis products in this system, mononuclear cells (MNC) of both origins were cultured. As related to CD34+ cell content, CAFC yields after five weeks' culture were in the same range in bone marrow and leukapheresis stemming from patients with efficient mobilization of hematopoietic cells. In purified CD34+ cell fractions, the CAFC yield per inoculated cell number was considerably higher than in MNC; however, if the CAFC number was related to the inoculated CD34+ cell number in MNC and after purification, the yield was four to eight times decreased in purified fractions. Addition of the mature cells brought the CAFC yield back up to the numbers obtained in the unseparated MNC fraction. By contrast, slightly more advanced progenitors per CAFC were found in cultures of purified hematopoietic cells from both origins than in whole MNC. The results suggest that mature human accessory cells give noticeable support to recruitment of early progenitors on this feeder but lead to lower yield of GM progenitors.

Adult↗
PubMed1998

Role of the CD34+ 38- cells in posttransplant hematopoietic recovery.

Using three different statistical tests in parallel, we showed in a preliminary study that neither mononuclear cells, CD34+ 33+ or 33- cells, nor CD34+ 38+ cells significantly correlated with engraftment kinetics following autologous blood cell transplantation (ABCT). We additionally demonstrated here, in a series of patients suffering from malignant diseases, that the graft content in CD34+ 38- cells is individually a more sensitive indicator of the earliest, as well as the latest post-ABCT trilineage hematopoietic recovery than the colony-forming units-granulocyte-macrophage and even the total CD34+ cell content. This suggests that the CD34+ 38- cell population is itself subdivided into two more subsets, one being already lineage-committed and responsible for short-term engraftment, the other containing only very primitive hematopoietic cells responsible for sustained engraftment. Strong arguments favor the probability that these subsets correspond to HLA-DR+ and DR cells, respectively. We also defined an optimal threshold value of 0.05 x 10(6) CD34+ 38- cells/kg of the patient's body weight (b.w.) above which a rapid and sustained trilineage engraftment safely occurs. In fact, infusion of lower numbers of cells seems to have a more significant impact on long-term compared to short-term neutrophil recovery and on platelet kinetics engraftment. We additionally looked for the eventual influence on engraftment time of the type of disease, and of post-ABCT administration of hematopoietic growth factors (HGF). When the type of disease appeared to have no influence on the engraftment time, posttransplant HGF administration significantly reduced the time to trilineage engraftment in patients transplanted with < 0.05 x 10(6) CD34+ 38- cells, thus justifying it in case of reinfusion of low numbers of CD34+ 38- cells. On the other hand, the administration of HGF after infusion of more than 0.05 x 10(6) CD34+ 38- cells/kg b.w. did not hasten more, or only very little, the engraftment time, thus becoming not only unprofitable for the patients but costly as well.

ADP-ribosyl Cyclase↗
PubMed1998

Primordial role of CD34+ 38- cells in early and late trilineage haemopoietic engraftment after autologous blood cell transplantation.

In order to better define which cell subset contained in graft products might be the most predictive of haemopoietic recovery following autologous blood cell transplantation (ABCT), the relationships between the amounts of reinfused mononuclear cells (MNC), CFU-GM, total CD34+ cells and their CD33 and CD38 subsets. and the successive stages of trilineage engraftment kinetics, were studied in 45 cancer patients, using the Spearman correlation test, a linear regression model and a log-inverse model. No relationship was found between the infused numbers of MNC, CD33+ and CD33- subsets observed and the numbers of days to reach predetermined absolute neutrophil (ANC), platelet and reticulocyte counts. The infused numbers of CFU-GM, CD34+ and CD34+ 38+ cells correlated inconstantly with haemopoietic recovery parameters. The strongest and the most constant correlations were significantly observed between the infused numbers of CD34+ 38- cells and each trilineage engraftment parameter. The log-inverse model determined a threshold dose of 0.05 x 10(6) (= 5 x 10(4)) CD34+ 38- cells/kg, below which the trilineage engraftment kinetics were significantly slower and unpredictable. Post-transplant TBI-conditioning regimens increased the low cell dose-related delay of engraftment kinetics whereas post-transplant administration of haemopoietic growth factors (HGF) seemed to abrogate this delay. This would justify clinical use of HGF only in patients transplanted with CD34+ 38- cell amounts lower than the proposed threshold value. This study suggests that the CD34+ 38- subpopulation, although essentially participating in late complete haemopoietic recovery, is also composed of committed progenitor cells involved in early trilineage engraftment.

ADP-ribosyl Cyclase↗
PubMed1998

Comparative analysis of class I, II and III epitope-detecting CD34 monoclonal antibodies by quantitative flow cytometry.

UNLABELLED: The aim of this study was to compare different CD34 monoclonal antibodies (MAbs) belonging to three different classes: MY10 class I, QBend10 class II, a mixture of three selected MAbs class I and II designated as CD34 Pool, and 8G12 class III. Bone marrow (BM) samples from 13 healthy donors were analyzed for: 1) percentage of CD34+ cells, 2) quantitative expression of CD34 epitopes (antigen's density - AgD) using a quantitative indirect immunofluorescence (QIFI) test, 3) study of CD34+ cell subsets defined by CD34 and CD38 coexpression. 8G12 MAb showed the highest reactivity with regard to the percentage of detected CD34+ cells and AgD on these cells. A nearly identical percentage of CD34+ cells was detected with CD34 Pool, but with a lower AgD. With QBend10, the percentage of CD34 expressing cells was insignificantly decreased and the AgD was slightly lower. The expression of the MY10 epitope was the lowest and was detected on the lowest number of CD34+ cells. Concerning CD34 and CD38 coexpressing subset, we observed that 8G12 class III MAb detected CD34loCD38dim cells with comparable efficiency with MY10 class I MAb, but with significantly higher level than QBend10 class II and CD34 Pool class I+II MAbs. The CD34hiCD38dim subset was detected with the same efficiency by QBend10, CD34 Pool or 8G12 MAbs but with significantly higher frequency than MY10 MAb. IN CONCLUSION: class II and III MAbs appear preferable for flow cytometric quantification of CD34+ cells; for CD34+ cell subsets determination class III MAbs should be suitable.

ADP-ribosyl Cyclase↗
PubMed1994

Isolation and identification of two CD34+ cell subpopulations from normal human peripheral blood.

Circulating CD34+ progenitors were separated from normal human peripheral blood on the basis of size and density by counterflow centrifugal elutriation (CCE). The CD34+ cells, 0.15% of peripheral blood mononuclear cells, were heterogeneous with respect to their elutriation characteristics, mainly size and density. The least mature CD34+ cells, characterized by lack of CD38 antigen, were predominantly found in the small lymphoid cell fraction. In fractions containing larger and denser cells (large lymphocytes, monocytes, and granulocytes), CD38 was increasingly expressed on the CD34+ cells, as were lineage commitment markers CD10 (B lymphoid), CD33 (myeloid), CD13 (myelomonocytic) and CD71 (erythroid) antigens. The smaller and less dense CD34+ cells expressed CD34 antigen brightly while the larger and denser CD34+ cells expressed it dimly. The smaller and less dense CD34+ high cells failed to establish colony growth in short-term culture while the larger and denser CD34+low cells gave rise to high counts of colony forming units-granulocyte macrophage (CFU-GM). Physical separation on the basis of size and density by CCE differentiates between two main classes of steady-state CD34+ cells from normal human peripheral blood. The smaller and less dense CD34+high cells correspond to the earliest progenitors that express differentiation markers poorly but CD34 antigen brightly, do not give rise to short-term colony growth in vitro, and thus represent indirect evidence for pluripotent hematopoietic stem cells (PHSC). The larger and denser CD34+low cells are the more mature progenitor cells, already committed to myeloid, lymphoid or erythroid differentiation but only dimly expressing CD34 antigen, and these cells were responsible for short-term colony growth in vitro.

Adult↗
PubMed1988

Collection of circulating stem cells and their use for autograft in adults with acute lymphoblastic leukaemia.

The level of peripheral blood granulocyte-monocytic precursors (PB CFU-GM) was studied serially in 10 adult patients with acute lymphoblastic leukaemia (ALL) in early complete remission after induction chemotherapy. The patients were distributed into 2 main groups according to the morphological French-American-British classification: ALL2 and ALL3. Collection of circulating stem cells (CSC) by cytapheresis was performed in 7 of these 10 patients with satisfactory results, except in 2 ALL2 patients, both of whom had chromosome translocation, which could have been a contributing factor. It appears, moreover, that even with 2 or 3 inductions courses, the more intensive the chemotherapy regimen in previously non-treated patients, the higher the peak of PB CFU-GM and the better the collection of CSC. The measurement of CFU-GM is certainly a less effective indicator of pluripotent stem cells in blood than in bone marrow, and it is probably necessary, but sufficient, to inject 5 times more CFU-GM than normally injected in marrow transplants to allow prompt and stable engraftment. The feasibility of this new graft technique seems for the moment undeniable, the main problem in ALL is the risk of relapse.

Adult↗
PubMed1984

[Quantitative method of measuring platelet ATP released in vitro in the presence of various aggregating agents].

A new method for quantitative study of the release of ATP during platelet aggregation is described. The measures have been done by bioluminescence with ADP, collagen, arachidonic acid as inducing agents in 20 normal subjects. Different characteristics of quality of the method have been evaluated to define it as a "routine" test. The results, expressed in moles (M) of ATP by 1 X 10(6) platelets, are different according to the various inducing agents. In association with the study of the platelet aggregation this method should allow to have a better understanding of the anomalies of platelet functions in different diseases, and, may be, to define states of platelet "activation" as done by the study of the release of beta-thromboglobulin and of platelet factor 4.

Adenosine Diphosphate↗