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V Witt

Publications and source records attributed to V Witt.

12 recordsLinked to original sources
PubMed2003

Monocyte enrichment from leukapharesis products for the generation of DCs by plastic adherence, or by positive or negative selection.

BACKGROUND: DCs for use in immunotherapy are frequently generated from peripheral blood monocytes. However, there are different approaches to monocyte enrichment. METHOD: Plastic adherence is a widely used method for the enrichment of monocytes collected in a leukapheresis procedure. Alternatively,monocytes may be enriched by positive selection using magnetic beads coupled to CD14 Abs, or by cell depletion using beads coupled to Abs against CD2 and CD19 to remove non-monocytes. RESULTS: Positive selection resulted in the highest purity of immature DCs (97 +/- 1%), but in a low yield (8 +/- 3%). In contrast, depletion of non-monocytes gave a good yield (21 +/- 6%), but insufficient purity (42 +/- 10%). Conventional adherence procedures resulted in a good yield (25 +/- 5%) and reasonable purity (72 +/- 4%). All three monocyte enrichment procedures resulted in DCs that underwent maturation upon exposure to a combination of lipopolysaccharide and IFN-gamma. These DCs had a typical immune phenotype, they released similar amounts of IL-12, and had the capacity to support MLR. CONCLUSION: Our data provide a basis to choose a monocyte enrichment procedure that favors high purity or a high yield. However, if a manual open system suffices, plastic adherence is a reasonable alternative.

Antigens, Surface↗
PubMed2001

Collection efficiencies of MNC subpopulations during autologous CD34+ peripheral blood progenitor cell (PBPC) harvests in small children and adolescents.

There is increasing demand for mononuclear cell (MNC) harvests not only for PBPC but also for immune therapies using dendritic cells and donor lymphocytes. We determined the collection efficiencies (CE) of various MNC subpopulations during CD34+ cell harvests using a Fenwal CS 3000 Plus Omnix system in small children and adolescents. The cell content of 140 leukapheresis products (LP) was prospectively evaluated in 45 pretreated patients with solid tumors and hematological malignancies. The median age was 12 years (range 0.8-22), and the median body weight (BW) 43 kg (range 9-92). Depending upon the BW of the patients, the media used for priming were saline (SP) in 86, human albumin (HA, HAP) in 10, and packed red blood cells (BP) in 44 apheresis procedures. The major nucleated cell (NC) fractions collected were monocytes (52% of NC) and CD3+ T cells (26%). The median cell yield for monocytes was 174 * 10(6)/kg (range 24-613) representing a CE of 55%. The median number of CD3(+) T cells was 84 * 10(6)/kg (range 5.6-380; CE = 74%). CD34+ cells represented a very small cell fraction of the LP (1.3% of NC), with a median yield of 4.2 * 10(6)/kg (range 0.2-87) and a CE of 63%. The cell yield of various MNCs was significantly correlated with the cell count in the peripheral blood (PB) and with the blood volume processed (ANOVA, P < 0.0001). No influence on the CE was observed for the priming procedure, the patients' age or sex, or the other adaptations used in the harvesting protocol. In conclusion, the Fenwal CS 3000 Plus OMNIX system with the CD34+ cell program and the described adaptations, is also predictably useful for harvest of monocytes or lymphocytes in pediatric patients. We present regression equations that predict the cell yield of various MNC subpopulations in apheresis products.

Adolescent↗
PubMed2000

Permanent tunneled silicone central venous catheters for autologous PBPC harvest in children and young adults.

Children with high risk malignancies are usually given permanent (Hickman-type) tunneled silicone rubber central venous catheters (silicone CVCs) for the administration of chemotherapy. In the past, these children received an additional short-term polyurethane dialysis CVC for stem cell apheresis. To avoid placement of an additional short-term CVC, we started in 1995 to use pre-existing silicone CVCs for PBPC harvests. From May 1996 to February 1999 we evaluated 165 harvests in 37 children and 14 young adults (16-28 years) treated with high-dose chemotherapy and stem cell support, comparing CD34+ cell harvest efficiency, catheter tolerability, and complications in three different approaches to vascular access. Pre-existing silicone CVCs (64%) or peripheral venous cannulae (15%) were the first choice for venous access. Only when these failed were polyurethane CVCs (21%) used. No significant difference was seen between these three groups, even after dividing the silicone CVC group (105 harvests in 32 patients) into three subgroups according to weight and age. The most frequent problems were citrate toxicity (n = 33), mechanical obstruction inside (n = 9) and outside the cell separator (n = 2), decreased draw line flow in silicone CVCs (n = 7), decreased draw line flow in peripheral venous cannulae (n = 6), and one occlusion in a polyurethane CVC. Pre-existing CVCs and peripheral venous cannulae functioned efficiently when used as a draw line in 79% of the apheresis procedures without significantly reducing single harvest efficiency or catheter tolerability. Consequently, the risks and costs associated with the placement of a dialysis CVC could be avoided in the majority of cases. Bone Marrow Transplantation (2000) 26, 781-786.

Adolescent↗
PubMed1999

Low incidence of molecular evidence for tumour in PBPC harvests from patients with high risk Ewing tumours.

Reverse transcriptase polymerase chain reaction (RT-PCR) was applied to evaluate the frequency of tumour cells in PBPC products from 15 high risk Ewing tumour (ET) patients who were treated according to EICESS 92 with high-dose chemotherapy (HDC) and stem cell rescue. Initial tumour cell contamination of the bone marrow (BM) detected by light microscopy was found in five and by RT-PCR in eight cases. RT-PCR was performed on each PBPC sample repeatedly at a sensitivity comparable to 20-100 highly EWS-Fli1 expressing tumour cells per 10 ml of fresh blood. Irrespective of the extent of BM involvement at diagnosis, all BM samples obtained before harvest were RT-PCR negative. Among 12 of 35 analysed apheresis products with single positive RT-PCR results only one sample tested reproducibly positive for tumour cell contamination in independent determinations. These preliminary data suggest that tumour cell contamination of PBPC is rarely found in patients with ET.

Adolescent↗
PubMed1999

Transplantation of highly purified peripheral blood CD34+ cells from HLA-mismatched parental donors in 14 children: evaluation of early monitoring of engraftment.

HLA-mismatched family members may represent an important cell source for patients that require stem cell transplantation but lack both a matched sibling donor and a closely matched unrelated donor. We report the outcome of 19 transplantations from HLA two- or three- loci mismatched parental donors in which 14 pediatric patients with hematological malignancies or other disorders, received a median of 21.5 x 106 (range, 5.4-58) highly purified CD34+peripheral blood stem cells (PBSC), as well as 4.7 x 104 (range, 0.4-12) donor T cells per kg body weight. T cell depletion was performed using a two-step CD34-positive selection on two different magnetic beads devices. Ten of 14 patients presented with rapid myeloid engraftment. The four patients who presented with graft failure (two non-engraftments, two rejections) received a second stem cell graft and one a third. Graft rejection was detected early by polymerase chain reaction (PCR) analysis of FACS-sorted T cells. Eight of the 14 patients are still alive after a median observation period of 15. 6 months (range, 3-31.3) with full donor chimerism in all hematopoietic cell lineages. No acute organ graft-versus-host disease (GVHD) and no chronic GVHD have occurred. One patient experienced relapse of leukemia. We conclude that transplantation of allogeneic PBSC from haploidentical donors will open new perspectives for pediatric patients for whom an HLA-matched stem cell graft is not available. Close monitoring of recipient and donor hematopoiesis might be of clinical value, to recognize early engraftment or rejection.

Adolescent↗
PubMed1999

Leucocyte transfusions from rhG-CSF or prednisolone stimulated donors for treatment of severe infections in immunocompromised neutropenic patients.

Sepsis in profound neutropenia after chemotherapy is associated with high mortality despite appropriate antibacterial or antifungal treatment. In a prospective phase I/II study we evaluated the feasability and efficacy of leucocyte transfusions (LT) in patients with malignancies or haematological disorders who were suffering from severe bacterial or fungal infection during therapy-related bone marrow aplasia. 30 patients with severe neutropenia and clinical signs of life-threatening sepsis not responding to adequate treatment, received LT from rhG-CSF-stimulated family donors or from prednisolone-primed volunteers. A total of 301 LT were administered. The median number of LT per patient was seven (range three to 65), the median duration of LT treatment was 8 d (range 2-35). The white cell count (WBC), absolute neutrophil count (ANC) and lymphocyte count of the concentrates from rhG-CSF-stimulated donors were significantly higher than those from prednisolone-primed volunteers (P = 0.0001). Despite the critical condition of the patients, LT were generally well tolerated. Only 39 (12.9%) LT were associated with adverse reactions. The transfusion of leucocytes collected by continuous flow leukapheresis from both rhG-CSF and prednisolone stimulated donors resulted in a measurable increment of the peripheral leucocyte and ANC counts in our patients. On day 100 after the first LT, 20/30 patients were alive with complete clearance of the infection.

Adolescent↗
PubMed1999

Five-year-survey of invasive aspergillosis in a paediatric cancer centre. Epidemiology, management and long-term survival.

The epidemiology, management, and long-term survival of invasive aspergillosis was assessed in a prospective, 5-year observational study in 346 unselected paediatric cancer patients receiving dose-intensive chemotherapy for newly diagnosed or recurrent malignancies. Invasive aspergillosis occurred exclusively in the context of haematological malignancies, where it accounted for an incidence of 6.8% (n = 13 of 189). The lung was the primary site in 12 cases, and dissemination was present in three of those. Prior to diagnosis, the overwhelming majority of patients had been profoundly neutropenic for at least 14 days (n = 11 of 13) and were receiving systemic antifungal agents (n = 10 of 13). Clinical signs and symptoms were nonspecific but always included fever. All 11 patients who were diagnosed and treated during lifetime for a minimum of 10 days responded to either medical or combined medical and surgical treatment, and seven were cured (64%). Nevertheless, the overall long-term survival was merely 31% after a median follow-up of 5.68 years after diagnosis. Apart from refractory or recurrent cancer, the main obstacles to successful outcome were failure to diagnose IA during lifetime and bleeding complications in patients with established diagnosis. The frequency of invasive aspergillosis of greater than 15% in paediatric patients with acute myeloblastic leukaemia and recurrent leukaemias warrants the systematic investigation of preventive strategies in these highly vulnerable subgroups.

Adolescent↗
PubMed1998

Resolution of early cytomegalovirus (CMV) infection after leukocyte transfusion therapy from a CMV seropositive donor.

A 2 year and 8 month old CMV-negative boy suffering from stage III neuroblastoma underwent ABMT in first very good partial remission. He acquired early CMV infection on day +5, followed by consecutive graft failure and severe sepsis, and the clinical course deteriorated. Between days +16 and +21, he received seven leukocyte concentrates (LC) collected from a healthy, but CMV-IgG-seropositive relative stimulated with G-CSF (filgastrim, 5 microg/kg/day). A median of 5.7 x 10(10) neutrophils/m2/day (range, 1.2-8.3) were transfused, corresponding to a T cell number of roughly 4 x 10(8) CD3+ cells/kg/day. After infusion of the LCs, PCR analysis became negative for CMV and the patient received his rescue bone marrow. One year after ABMT, he is in complete remission and in good clinical condition. Our results suggest that the T cells infused together with the irradiated leukocytes played a major role in eradicating the CMV infection in this patient.

Adoptive Transfer↗
PubMed1997

Quantification of CD34+ cells: comparison of methods.

BACKGROUND: Quantification of CD34+ stem and progenitor cells is predominantly performed by flow cytometric analysis of cells prepared by whole blood staining and red cell lysis. This method also includes cell washing, which is thought to cause the destruction and loss of some of the nucleated cells (NCs). To address this cell loss and its influence on the outcome of enumeration, three techniques for preparing cells for quantification of CD34+ cells were compared. STUDY DESIGN AND METHODS: Blood (n = 179), bone marrow (n = 60), and leukapheresis components (n = 64) were examined by the use of density separation of mononuclear cells (MNCs) and two red cell-lysis procedures (wash and no-wash). Cell counts were determined in the original materials and after cell preparation. Absolute CD34+ cell counts were calculated using the flow cytometry-analyzed proportions of CD34+ cells and the various white cell counts. RESULTS: Depending on the cell source and the cell preparation chosen, the loss of NCs ranged between 12 percent and 89 percent of the original white cell number. This loss of NCs was exclusively due to cell washing and predominantly affected granulocytic cells. Analysis of the flow cytometry data revealed that the relative CD34+ values in blood and bone marrow were roughly threefold higher in density separated MNCs than in those that underwent the lyse-and-wash procedure. Calculation of absolute CD34+ cell counts confirmed that the MNC procedure underestimated the CD34+ cell content by a median of 26 percent (blood), 21 percent (bone marrow), and 5 percent (leukapheresis component) when compared with the median yield from analysis and cell counting performed after the lyse-and-wash procedure. On the other hand, the conventional lysis procedure, which applies the original white cell counts for CD34+ quantification, was shown to overestimate the CD34+ cell content by a median of 1.2-fold, 1.33-fold, and 1.13-fold, respectively. CONCLUSION: Neither density separation nor the whole-blood lysis procedure seems appropriate for optimal CD34+ quantification.

Ammonium Chloride↗
PubMedDate not supplied

Effects of dose-reduced Medac L-asparaginase on coagulation in trial ALL-BFM 2000.

BACKGROUND: Glucocorticoids and L-asparaginase (L-ASP) are essential elements of contemporary chemotherapy of childhood acute lymphoblastic leukemia (ALL). Both cytotoxic drugs are well-known to induce significant alterations in hemostasis, especially affecting the inhibitors of coagulation including antithrombin III (AT III), protein C and protein S. PATIENTS AND METHODS: The objectives of the present prospective study were to analyze the course and degree of the changes of several coagulation proteins during induction therapy of 16 patients treated according to the Berlin-Frankfurt-Münster (BFM) ALL protocol 2000. The induction protocol included a 7-day mono-therapy with glucocorticoids followed by 4 weeks with additional vincristine, daunorubicin and E. coli L-ASP (Medac) which was administered at a dosage of 5000 IU/m (2) 8-times at 3-day intervals. RESULTS AND CONCLUSIONS: This analysis is the first to show that 5000 IU/m (2) of the Medac L-ASP leads to a less pronounced decrease of the plasma AT III and fibrinogen concentrations during induction therapy (after the 5 (th) L-ASP dose), as compared to previous BFM protocols which used the Medac L-ASP in a dosage of 10 000 IU/m (2). Our results confirmed that following a mono-therapy with glucocorticoids the AT III, protein C and protein S levels increased while the fibrinogen level decreased. As the D-Dimers remained within the normal range during the 3 weeks of L-ASP combination chemotherapy and none of the patients suffered a thromboembolic event, we also concluded that despite of the significant decrease of anticoagulant proteins, there might be a balance between coagulation and fibrinolysis; thus the D-Dimers may eventually serve as a helpful indicator for therapeutic interventions.

Adolescent↗
PubMedDate not supplied

Automobile seat belt practices of pregnant women.

Despite the fact that seat belts have been proved effective in reducing deaths and serious injuries, many pregnant women do not wear seat belts. A study was conducted to examine the seat belt practices of pregnant women. Of the 87 women who were interviewed, 40 reported using seat belts regularly during pregnancy. However, almost one-third of them did not adjust the belts properly for maximum protection. Older women and those with more education were more likely to use their seat belts routinely. Only 20 women recalled receiving information about seat belts during their pregnancies, but 48 women would have liked to receive more information.

Adolescent↗