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V Deneys

Publications and source records attributed to V Deneys.

At least 37 records · Page 2Linked to original sources
PubMed1999

Belgian consensus recommendations for flow cytometric immunophenotyping. The Belgian Association for Cytometry/Belgische Vereniging voor Cytometrie/Association Belge de Cytométrie.

This paper summarises the guidelines and recommendations that were generated during a number of discussion forums attended by the majority of Belgian cytometry laboratory professionals. These forums focused on the rational and optimal use of flow cytometric evaluations in the clinical laboratory setting. The aim was to improve the coherence of the testing panels and the quality of the results and--as such--the clinical diagnostic information. It was also the aim to provide the Belgian prescribing physician and interested laymen with an updated overview of the flow cytometric possibilities. Emphasis is placed on immunophenotyping of haematological malignancies, hematopoietic progenitor cell counting and follow-up of the viral infection caused by the human immunodeficiency virus.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Improved IL-2 detection for determination of helper T lymphocyte precursor frequency in limiting dilution assay.

In the context of allogeneic bone marrow transplantation, an accurate estimate of the risk of developing graft-versus-host disease (GVHD) is of major interest. The pre-transplant frequency of donor's helper T-lymphocyte precursors (HTLp) directed against host's antigens may be helpful in predicting this risk. This technique relies on an indirect measurement of interleukin-2 (IL-2) secreted by the HTLp, as assessed by the proliferation of an IL-2 dependent cell line. Many authors use the murine CTLL-2 cell line in this assay, but these cells do not respond to the presence of minute amounts of IL-2 in the culture medium, and thus do not discriminate between the absence or the presence of very low levels of IL-2. We therefore decided to compare CTLL-2 with another IL-2 dependent cell line, the murine A9.12 cell line. A comparison was made using serial dilutions of recombinant human IL-2, limiting dilutions of baby hamster kidney (BHK) cells transfected with human IL-2 gene and in the context of clinical tests performed for the detection of pre-transplant HTLp. Both the sensitivity and reliability of the tests were better using A9.12. We conclude that the A9.12 cell line might be a more suitable tool for pre-transplant HTLp determinations before allogeneic bone marrow transplantation or whenever low IL-2 levels are to be measured.

Animals↗
PubMed1995

The immune profile of multiple sclerosis: T-lymphocyte effects predominate over all other factors in cyclophosphamide-treated patients.

It is widely believed that multiple sclerosis is a T-cell mediated autoimmune disease associated with abnormalities in immunoregulation. This large, prospective study evaluated the lymphocyte immunophenotypic profile of 246 MS patients, divided clinically into a remitting/relapsing group (n = 176) and a progressive group (n = 70), and compared their results to those of 117 healthy controls. All patients were found to have significantly elevated percentage and absolute numbers of IL2R+CD3+ cells as well as depressed percentages of CD45RA+CD4+ cells. However, when the factor of treatment with cyclophosphamide (CY) versus no treatment or treatment with other agents was used to group patients, dramatic declines in both percentages and absolute numbers of CD45RA+CD4+ cells were discovered. These declines were associated specifically with CY and and could be explained by this factor independent of the clinical state of the patient. The effects were seen in patients undergoing current treatment or in those exposed to CY in the near or remote past. These findings highlight the confounding effect of specific treatments on the immune profile of MS patients groups and suggest that there may be important implications for cellular function and clinical outcome in these and other patient groups.

Adult↗
PubMed1995

[Immunologic tolerance of fetal allograft].

In mammals, reproduction involves two potentially incompatible mechanisms: viviparity and development of a competent immune system. Thus the maternal and foetal organisms must respond by developing immunologic tolerance. The phenomenon does not involve total immunosuppression, but includes several highly precise processes initiated at conception. It is known that cell- and humour-mediated processes occur but their relative importance remains to be elucidated. Cytokines, especially those mediating T-helper2 cell response appear to play a predominant role in inducing immunologic tolerance to the foetal allograft. A better understanding of these mechanisms could have major implications in the diagnosis and treatment of repeated miscarriage and unexplained infertility.

Abortion, Habitual↗
PubMed1995

Long-term culture of autologous transplanted bone marrow for acute myeloid leukaemia: evidence for an in vitro haemopoietic defect and lack of correlation with the speed of engraftment.

Haematological recovery after autologous bone marrow transplantation (BMT) for acute myeloid leukaemia (AML) is often delayed and available laboratory assays cannot accurately predict speed of engraftment. By using the long-term bone marrow culture (LTBMC) method, we attempted to define the haemopoietic defect underlying this slow engraftment, and assessed the usefulness of LTBMC in predicting engraftment. Cryopreserved bone marrow (BM) harvested from three different groups (AML autografts, n = 18; autografts for non-leukaemic diseases, n = 23; normal donors. n = 10) were cultured and their growth was compared and correlated with the speed of engraftment. In the AML autografts, non-adherent and adherent progenitor production was significantly reduced compared with normal BM during the whole culture period (P < 0.01). None of the LTBMC parameters was found to correlate with engraftment after autologous BMT. The non-leukaemic autografts showed progenitor production intermediate between normal and AML autografts. Their progenitor content at the end of the culture period (reflecting the stem cell pool) was not statistically different from normal BM. In this group, most of the progenitor cell contents, during LTBMC correlated with neutrophil (rs = -0.618 to -0.879, P < 0.01) and platelet (rs = -0.479 to -0.707, P < 0.02) recovery. The conclusion drawn from these results is that AML autografts are defective in their ability to sustain in vitro haemopoiesis, but this in vivo defect does not correlate with the slow haemopoietic recovery after autologous BMT. In contrast, LTBMC of autografts for non-leukaemic diseases, whose defect affects the stem cell pool to a lesser extent than BM in AML correlates with the speed of engraftment.

Acute Disease↗
PubMed1995

2-Chlorodeoxyadenosine (CdA) for patients with previously untreated chronic lymphocytic leukemia (CLL).

The encouraging therapeutic results attained with the purine analogue CdA in patients with previously treated CLL prompted us to assess its potential in untreated CLL patients. Nineteen patients, 13 males and six females, median age 65 years (range 27-75), with previously untreated CLL were given monthly courses of CdA, 0.12 mg/kg/day as 2-h i.v. infusions for 5 days, until maximum response or excessive toxicity. Five patients with Binet's stage A, 10 with stage B and four with stage C CLL entered the study. After a median of five courses of CdA (range 1-9) nine complete responses (CR = 47%, CI: 24-69%), five partial responses (PR = 26%, CI: 7-46%) and five failures (= 26%, CI: 7-46%) were recorded. In five complete responders and in one partial responder cytofluorometric analysis of blood and/or bone marrow failed to demonstrate a residual clonal B cell population. A search for residual disease by PCR technology and by immunostaining of bone marrow biopsies however disclosed residual leukemic cells in these six cases. Adverse reactions included fever of unknown origin (n = 3), pneumonia (n = 2), herpes simplex infection, herpes zoster, an anal abscess, a cutaneous rash, autoimmune hemolysis and mental disturbance (one patient each). In this small cohort, neither age, stage, blood counts, cytogenetics or pattern of bone marrow infiltration at inclusion were predictive for response. From these preliminary data, we conclude that CdA has remarkable short-term efficacy in patients with previously untreated CLL. However, toxicity is not negligible and long-term benefit from therapy with CdA still has to be established.

Adult↗
PubMed1994

Age-related changes in human blood lymphocyte subpopulations. II. Varying kinetics of percentage and absolute count measurements.

A reference range for lymphocyte populations, with particular emphasis on T lymphocyte subsets, was obtained for normal individuals covering age cohorts from birth through adulthood. This report confirms and extends findings from a developmental reference range published earlier (1). Absolute numbers of WBC, lymphocytes, and T, B, and NK subsets decline significantly during childhood. However, differences in the rate of decline of certain lymphocyte subsets leads to discordance between absolute numbers and percentages. Those lymphocyte subsets which decline less rapidly with age than the total lymphocyte count will show an increase in percentage, whereas those which decline more rapidly will show further declines in percentage values. T cell percentages were seen to increase over time whereas B cell percentages decline. Markers of immaturity such as CD45RA on CD4 cells and CD38 on CD8 cells declined in both percentages and absolute numbers. Activation markers, such as HLA-DR on CD8 cells and IL2-R on CD3 cells, increased in percentages with time but changed inconsistently in cell number from infancy to adulthood. These findings extend the lymphocyte references range to markers thought to be informative in various disease states, including HIV infection.

Adolescent↗
PubMed1994

Bedside transfusion errors. A prospective survey by the Belgium SAnGUIS Group.

The true incidence of bedside transfusion errors, i.e. those happening when blood products have left the blood bank, is underestimated because published figures rely on reporting of clinically relevant events or on indirect methods. The SAnGUIS project assessing blood practice in a prospective and randomized fashion for 6 elective surgical procedures gave the opportunity to trace all transfused units and to identify steps at risk during blood delivery in surgery. We considered transfusion of a wrong unit as a major error and poor execution or documentation as a recording error. Over 15 months, 808 patients out of 1,448 were transfused with 3,485 units. A total of 165 errors were found after blood products had left the blood banks. Seven were misidentifications (0.74% of patients, 0.2% of units). Eight other major errors occurred in 4 (0.5%) patients. Major errors occurred during nonemergency situations, in wards or intensive care units. The remaining ('recording') 150 errors consisted of misrecordings (61), mislabellings (6), or failures to document transfusions in the medical records (83). All errors were uneventful except one misidentification which induced a transient, yet unreported, reaction. The 'descending' inquiry method used for this study showed that most errors pass unnoticed and are therefore not reported. Measurement of error rates may constitute an important quality indicator. Retrospective information of this survey to the concerned staff people provided an impetus to take adequate measures to reduce these bedside errors.

Belgium↗
PubMed1994

Reliable and very sensitive flow-cytometric method for counting low leucocyte numbers in platelet concentrates.

Reduction of leucocytes in blood components, achieved by filtration, may reduce the risk of HLA alloimmunization, virus transmission, and febrile reactions. Nevertheless, white blood cell (WBC) concentrations obtained in this way can be too low to be accurately counted with automated and manual techniques. We describe here a rapid, reliable, and very sensitive method for counting low leucocyte numbers using flow cytometry. WBC nuclei are labelled by propidium iodide. A known amount of fluorescein- and phycoerythrin-conjugated beads (Standard Brite, Coulter) is added as an indicator of the examined volume. The time required for analyzing one tube is approximately 5 min. This method was first validated by comparing WBC counts (120-2,570/microliters) assessed on a haemocytometer (Bürker) and by flow cytometry. The second step was to determine the sensitivity of the method: we diluted normal platelet concentrates with phosphate-buffered saline. The comparison of expected with observed values showed a very good correlation up to a concentration of 1 WBC/microliter. This technique is an accurate method that can be applied in blood bank quality controls and in clinical studies.

Flow Cytometry↗
PubMed1993

Cigarette smoking and chronic polyclonal B-cell lymphocytosis.

A syndrome associating a polyclonal increase of B-cells with binucleate lymphocytes in peripheral blood and a polyclonal increase of serum IgM, accompanied or not by splenomegaly and lymphadenopathy, has been reported in young to middle-aged women who are cigarette smokers. The majority of patients were HLA-DR7 positive and their clinical course remained stable over periods of years. We report four cases of this syndrome. In all patients, DNA analysis provided additional evidence that the lymphocytosis was polyclonal, while in one patient who met all other symptomatic criteria the total lymphocyte count was normal. This would suggest that unless careful attention is paid to the morphology of the lymphocytes, the syndrome may go undiagnosed.

Adult↗
PubMed1992

High-dose cytosine arabinoside intensification for acute nonlymphocytic leukemia in patients over 56 years of age.

One hundred and nine consecutive patients with de novo acute nonlymphocytic leukemia aged over 56 years were admitted with the intention of administering high-dose cytosine arabinoside (HD Ara-C) intensification. After remission induction, the patients were consolidated with a course of daunorubicin (30 mg/m2/day, days 1-3) and Ara-C (100 mg/m2/day, days 1-7), followed by the intensification (Ara-C, 2 g/m2/12 h, days 1-4). The planned induction course was not started in 13 patients because of cardiac failure or unsatisfactory general status. Remission was achieved in 55% (53/96) of the patients. Twenty-seven patients (28%) had refractory disease, seven died early during induction therapy, five died of hemorrhage and three of infection during the hypoplasia that followed induction treatment. Thirty-nine patients started consolidation and 32 had the planned intensification. In these last patients the 3-year leukemia-free survival (LFS) probability was 29% (SE, 8%). No patient died as a consequence of intensification. The relapse rate of the intensified patients did not differ from the relapse rate of those patients who did not receive the planned intensification (p = 0.12). The only pretreatment variables significantly associated with a better LFS were younger age (p = 0.02) and a low WBC at diagnosis (p = 0.04). For the whole patient group, the 3-year survival probability was 15% (SE, 4%). This study shows that elderly patients can tolerate HD Ara-C. The patients completing consolidation-intensification have a currently acceptable LFS. To what extent HD Ara-C contributed to the length of the remissions remains unclear.

Aged↗
PubMed1992

Age-related changes in human blood lymphocyte subpopulations.

Flow cytometric analysis of major lymphocyte populations and their subsets reveals age-related changes in the cellular human immune system. Immunophenotypic markers were evaluated in 110 normal pediatric subjects, divided into groups of newborn infants, infants aged 2 days to 11 months, and children aged 1 to 6 years and 7 to 17 years; results were then compared with those obtained from 101 normal adults aged 18 to 70 years. Comparisons among age groups from newborn infants through adults reveal progressive declines in the absolute numbers of leukocytes, total lymphocytes, and T, B, and natural killer (NK) cells. The percentages of T cells within the total lymphocyte population increase with age, in both CD4+ and CD8+ subsets. Percentages of B and NK cells are higher in newborn infants than in adults. The expression of the activation markers interleukin-2R and HLA-DR on T cells increases with age, as does the NK-associated expression of CD57 on CD8 cells. The proportions of B lymphocytes that coexpress CD5 or CDw78 decrease with age, whereas expression of Leu-8 and CD23 increases. The proportion of CD4 cells bearing the CD45RA and Leu-8 markers is consistently lower in adults than in children. These data may serve as a reference range for studies of pediatric subjects.

Adolescent↗