Biomedical subjects

Jane F Apperley

Publications and source records attributed to Jane F Apperley.

41 records · Page 3Linked to original sources

PubMed2002

Retrovirus-mediated gene transfer in primary T lymphocytes impairs their anti-Epstein-Barr virus potential through both culture-dependent and selection process-dependent mechanisms.

To modulate alloreactivity after hematopoietic stem cell transplantation, suicide gene-expressing donor T cells can be administered with an allogeneic T-cell-depleted bone marrow graft. Immune competence of such cells is a critical issue. The impact of the ex vivo gene transfer protocol (12-day culture period including CD3/interleukin-2 [IL-2] activation, retroviral-mediated gene transfer, and G418-based selection) on the anti-Epstein-Barr virus (EBV) potential of gene-modified cells has been examined. Cytotoxic (pCTL) and helper (pTh) cell precursor limiting dilution assays, interferon-gamma enzyme-linked immunospot, or fluorescence-activated cell sorter analysis after tetrameric HLA-A2/EBV peptide complexes revealed that the frequency of anti-EBV T cells was lower in gene-modified cells (GMCs) than in similarly cultured but untransduced T cells and was even lower than in fresh peripheral blood mononuclear cells, demonstrating both an effect of the culture and of the transduction or selection. The culture-dependent loss of EBV-reactive cells resulted from the preferential induction of activation-induced cell death in tetramer(+) cells. Replacing the initial CD3/IL-2 activation by CD3/CD28/IL-2 partially restored the anti-EBV response of GMCs by reducing the initial activation-induced cell death and enhancing the proliferation of EBV-tetramer(+) cells. Moreover, the G418 selection, and not the transduction, was directly toxic to transduced tetramer(+) cells. Replacing the G418 selection by an immunomagnetic selection significantly prevented the selection-dependent loss of EBV-specific cells. Overall, ex vivo gene modification of primary T cells can result in a significant reduction in EBV-reactive T cells through both culture-dependent and selection-dependent mechanisms. Improving immune functions of GMCs through modifications of the cell culture conditions and transduction/selection processes is critical for further clinical studies.

Cell Culture Techniques↗

PubMed2002

The post-transplant cytogenetic response to interferon is a major determinant of survival after autologous stem cell transplantation for chronic myeloid leukaemia in chronic phase.

We have analysed the outcome of 581 autologous stem cell transplants (SCT) for chronic myeloid leukaemia (CML) in first chronic phase reported to the European Group for Blood and Marrow Transplantation between 1983 and 1998. Out off 207 patients evaluable for cytogenetics within 6 months of SCT, 36 patients (17%) were in complete cytogenetic remission (CCR), 34 (16%) in major remission (MCR), 74 (36%) in minor remission (mCR) and 63 (31%) had no cytogenetic response (NR). Interferon (IFN) was given post SCT to 267 patients. Results of the cytogenetic analysis within 1-2 years from SCT were available for 117 patients, the majority of whom (n = 101) received IFN post SCT: 17 (15%) were in CCR, 18 (15%) in MCR, 24 (20%) in mCR and 58 (50%) NR. The median survival in this series was 96 months (71-125) from SCT. There was no difference in survival according to cytogenetic status pre- and immediately post SCT. However, patients in CCR or MCR at 1-2 years post SCT had a 10-year survival of 66% compared with 36% for patients in mCR or NR (P = 0.003). The 5-year survival for patients receiving IFN post SCT was 72% compared with 61% for patients not treated with IFN (P = 0.01). Out of 155 patients refractory to IFN pre SCT, 70% achieved a cytogenetic response post SCT, which was complete or major in 31%. IFN refractory patients who sustained a CCR or MCR for 1-2 years after SCT had an excellent outcome.

Adult↗

PubMed2002

Thrombotic thrombocytopenic purpura after allogeneic stem cell transplantation: a survey of the European Group for Blood and Marrow Transplantation (EBMT).

A survey was carried out among the European Group for Blood and Marrow Transplantation (EBMT) centres to determine the incidence, risk factors, treatment and outcome of thrombotic thrombocytopenic purpura (TTP) following allogeneic haematopoietic stem cell transplantation. TTP was defined as the simultaneous occurrence of red cell fragmentation, laboratory findings of haemolysis, red cell transfusion requirement and de novo or persistent thrombocytopenia caused by consumption, in the absence of disseminated intravascular coagulation. Forty-five centres reported all patients (n = 406) transplanted between July and December 1996. Twenty-three patients developed TTP; the risk of developing TTP was 6.7% at 2 years (95% CI: 4.1% to 9.3%). The median time of onset was 44 d (range 13-319) post transplantation. Significant risk factors for the development of TTP were female gender (P = 0.005) and an unrelated donor (P = 0.046). To treat TTP, cyclosporin administration was discontinued in 10 cases, plasma exchanges were performed in five cases and 12 patients received plasma infusions without plasma exchange. TTP resolved in 13 of the 23 patients (57%). The only factor predictive of resolution of TTP was the absence of nephropathy. Seven patients (30%) were alive at follow-up of 38-45 months from the onset of TTP. Sixteen patients died; the causes were multiple, only three patients had TTP as a central factor. The median time to death was 41 d (range 1-762 d) from the onset of TTP. TTP is a relatively frequent complication of allogeneic stem cell transplantation and it is associated with high mortality, though death is usually caused by multiple factors.

Adolescent↗

PubMed2002

ST1571 (imatinib mesylate) reduces bone marrow cellularity and normalizes morphologic features irrespective of cytogenetic response.

The tyrosine kinase inhibitor STI571 (imatinib mesylate, Gleevec) is an effective treatment for chronic myeloid leukemia (CML). We examined bone marrow samples from 53 patients with CML who were receiving STI571 in 3 multicenter phase 2 trials to assess morphologic changes and cytogenetic response to this drug. In most patients with initially increased blasts, the bone marrow blast count rapidly decreased during STI571 therapy. Reductions in cellularity, the myeloid/erythroid ratio (commonly with relative erythroid hyperplasia), and reticulin fibrosis (if present pretreatment) also were seen in most patients, resulting in an appearance resembling normal marrow in many cases. Eighteen patients (34%) had some degree of cytogenetic response. Surprisingly, these striking morphologic changes occurred irrespective of any cytogenetic response to STI571. Thus, STI571 seems to affect the differentiation of CML cells in vivo, causing even extensively Philadelphia chromosome-positive hematopoiesis to exhibitfeatures resembling normal hematopoiesis.

Antineoplastic Agents↗

PubMed2002

The use of imatinib (STI571) in chronic myelod leukemia: some practical considerations.

BACKGROUND AND OBJECTIVES: The new Abl tyrosine kinase inhibitor imatinib (imatinib mesylate, STI571) is very effective in the treatment of patients with chronic myeloid leukemia (CML). It induces complete hematologic control in >90% of patients with CML in chronic phase and preliminary data suggest that the incidence of complete cytogenetic remission may exceed 60% in previously untreated patients, though its capacity to prolong life in comparison with other agents has not yet been clearly established. It is also active in the management of patients in advanced phases of CML. INFORMATION SOURCES: We present here provisional indications for the use of imatinib in CML patients and give details of the dosage regimens we have used and side-effects we have encountered. STATE OF THE ART AND PERSPECTIVES: It is likely that the optimal usage of this important new agent will become better defined as more experience is gained.

Benzamides↗