Biomedical subjects

J F Apperley

Publications and source records attributed to J F Apperley.

At least 19 recordsLinked to original sources

PubMed2003

Autologous stem cell transplantation in multiple myeloma: improved survival in nonsecretory multiple myeloma but lack of influence of age, status at transplant, previous treatment and conditioning regimen. A single-centre experience in 127 patients.

High-dose therapy with autologous stem cell transplantation (ASCT) has become the treatment of choice for symptomatic eligible patients with multiple myeloma (MM). We report our centre experience and analyse retrospectively the prognostic influence of pretransplant characteristics and transplant modalities on response and survival. A total of 127 MM patients (median age: 55.2 years) were transplanted between 1994 and 2001. In all, 69 patients had IgG, 28 IgA, 23 light chain, one IgD and six non secretory MM. At the time of autograft, 6% of patients were in complete remission (CR), 73% in partial remission (PR), 12% showed minor response to previous treatment and 9% had stable or refractory disease. Prior to autograft, 79% of cases had received only one line of chemotherapy and 21% two or more lines. All patients received PBSC support after conditioning with 200 mg/m(2) melphalan alone (100 patients) or melphalan and TBI (27 patients). We evaluated the influence of age (using as cutoff value the ages of 55, 60 and 65 years), type of MM, status pre- and post-ASCT, number of lines of previous regimens, time of ASCT from diagnosis, year of autograft, dose of reinfused CD34+ cells, plasma cell infiltration and beta(2)-microglobulin at diagnosis on overall (OS) and progression-free survivals (PFS) to define patients with better prognosis. Following ASCT, 15% of patients were in CR and 81% in PR, while only two patients progressed. Median OS and PFS from transplantation were 50.4 and 23.5 months, respectively. Median OS from diagnosis was 79.7 months. Transplant-related mortality was 2.3%. Low levels of beta(2)-microglobulin and the achievement of CR post-transplant correlated with longer PFS (P<0.03 and P<0.01, respectively). The median PFS was 36.1, 23.9, 21.1 and 16.4 months for nonsecretory, IgG, IgA and light chain subtypes, respectively. Age was not an important prognostic factor at a cutoff value of 55 or 60 years. We conclude that ASCT is a safe and effective procedure even in resistant cases. The outcome was independent of age, time from diagnosis, previous treatment and conditioning regimen, but there was a tendency for better survival in the nonsecretory patients.

Age Factors↗

PubMed2003

Prognostic factors for patients with chronic myeloid leukaemia in chronic phase treated with imatinib mesylate after failure of interferon alfa.

We assessed clinical results in 145 patients with chronic myeloid leukaemia in chronic phase who satisfied criteria for interferon-alpha failure and were thus eligible for treatment with imatinib at the Hammersmith Hospital. We used univariate and multivariate analyses to develop a risk score based on features defined after treatment for 3 months. We identified a low neutrophil count and poor cytogenetic response (<35% Ph-negative marrow metaphases) at 3 months as principal independent predictive factors and incorporated them into a three-tier prognostic scoring system for individual patients. For patients in the low-, intermediate- and high-risk groups, the probabilities of survival at 24 months were 100, 82 and 40% (P<0.0001) and progression-free survival 100, 66 and 15% (P<0.0001), respectively. This Hammersmith prognostic scoring system was validated with an independent cohort of patients treated at another UK centre.

Adolescent↗

PubMed2001

Pregnancy outcomes after peripheral blood or bone marrow transplantation: a retrospective survey.

BACKGROUND: Some patients treated by transplantation of haemopoietic stem cells (peripheral blood or bone marrow) become permanently infertile, but others retain or recover fertility. We assessed the outcome of conception in women, and partners of men previously treated by autologous or allogeneic stem cell transplantation (SCT). METHODS: We sent questionnaires to 229 centres of the European Group for Blood and Marrow Transplantation. We sought details about the original disease, transplant procedure, and outcome of conception for both male and female patients. FINDINGS: 199 centres gave information relating to 19412 allogeneic and 17950 autologous transplant patients. 232 (0.6%) patients conceived after SCT. Crude annual birth rate for 4-month survivors of SCT was lower than the national average for England and Wales at 1.7 per 1000 patients. 312 conceptions were reported in 113 patients (74 allograft) and partners of 119 patients (93 allograft). Most pregnancies were uncomplicated and resulted in 271 livebirths. 28 (42%) of 67 allograft recipients had caesarean section compared with 16% in the normal population (difference =26% [95% CI 15-38]), 12 (20%) of 59 had preterm delivery compared with a normal rate of 6% (14% [4-24]), and 12 (23%) of 52 had low birthweight singleton offspring compared with a normal rate of 6% (17% [6-29]). INTERPRETATION: Pregnancy after SCT is likely to have a successful outcome. Pregnancies in allograft patients who have received total body irradiation should be treated as high risk for maternal and fetal complications.

Adolescent↗

PubMed2001

Early detection of BCR-ABL transcripts by quantitative reverse transcriptase-polymerase chain reaction predicts outcome after allogeneic stem cell transplantation for chronic myeloid leukemia.

The reverse transcriptase-polymerase chain reaction (RT-PCR) has become widely used for monitoring minimal residual disease after allogeneic stem cell transplantation (SCT) for chronic myeloid leukemia (CML). However, most of these studies were performed using qualitative RT-PCR, and the interpretation of the results obtained has been conflicting. The correlation of a quantitative RT-PCR test performed early after SCT (at 3 to 5 months) and long-term outcome of CML patients surviving for more than 6 months was studied. Between January 1991 and June 1999, data from 138 CML patients who received allografts were evaluated. Early RT-PCR results were classified as (1) negative if there were no BCR-ABL transcripts detected (n = 61), (2) positive at low level if the total number of BCR-ABL transcripts was less than 100 per microg RNA and/or the BCR-ABL/ABL ratio was less than 0.02% (n = 14), or (3) positive at high level if transcript levels exceeded the thresholds defined above (n = 63). Three years after SCT the cumulative incidence of relapse was 16.7%, 42.9%, and 86.4%, respectively (P =.0001). The relationship between BCR-ABL transcript level and probability of relapse was apparent whether patients had received sibling or unrelated donor SCT and also whether or not the transplantation was T cell depleted. The results suggest that quantitative RT-PCR performed early after SCT is useful for predicting outcome and may help to define the need for further treatment.

Actuarial Analysis↗

PubMed2001

Molecular mechanism for ganciclovir resistance in human T lymphocytes transduced with retroviral vectors carrying the herpes simplex virus thymidine kinase gene.

The herpes simplex virus thymidine kinase gene type 1 (HSV-Tk) ganciclovir (GCV) system is a novel therapeutic strategy for the modulation of graft-versus-host disease (GVHD), a major complication of allogeneic stem cell transplantation (allo-SCT). Retroviral-mediated gene transfer of the HSV-Tk gene into donor T lymphocytes before allo-SCT may allow their in vivo selective depletion after treatment with GCV. The expression of the HSV-Tk gene was analyzed in vitro in CEM cells, a human lymphoblastoid cell line, transduced with 2 different vectors, each containing the HSV-Tk gene and a selectable marker gene. GCV-resistant clones were identified within the clones expressing the marker gene. Characterization of the molecular events leading to this resistance revealed a 227-bp deletion in the HSV-Tk gene due to the presence of cryptic splice donor and acceptor sites within the HSV-Tk gene sequence. Furthermore, it was confirmed that this deletion was present in human primary T cells transduced with either vector and in 12 patients who received transduced donor T cells, together with a T-cell-depleted allo-SCT. In vivo circulating transduced T cells containing the truncated HSV-Tk gene were identified in all patients immediately after infusion and up to 800 days after transplantation. In patients who received GCV as treatment for GVHD, a progressive increase in the proportion of transduced donor T cells carrying the deleted HSV-Tk gene was observed. These results suggest that the limitations within the HSV-Tk/GCV system can be improved by developing optimized retroviral vectors to ensure maximal killing of HSV-Tk-transduced cells.

Antiviral Agents↗

PubMed2001

BCR-ABL-expressing cells transduced with the HSV-tk gene die by apoptosis upon treatment with ganciclovir.

The potential efficacy of prodrug activation of a transduced suicide gene in a cancer cell may be impaired or enhanced by oncoproteins produced by that cell. In the context of a gene therapy protocol for chronic myeloid leukemia (CML) we examined whether the Bcr-Abl fusion protein would have either of these effects. Thus, the mechanism of cell killing by transfer of herpes simplex virus thymidine kinase (HSV-tk) and subsequent ganciclovir (GCV) treatment was examined in pre-B (TonB210.1) cells and myeloid cells (32D) and in their BCR-ABL-expressing counterparts. HSV-tk-transduced cell lines, either in the presence or in the absence of BCR-ABL expression, became susceptible to GCV at concentrations which were nontoxic to the nontransduced cells. This susceptibility was represented by apoptotic cell death in all cases. Apoptosis was observed after 24 h of treatment with GCV in the tk-transduced parental cells and in the BCR-ABL-expressing TonB210.1 cells but only after a delay of more than 24 h in the 32Dp210 cells compared to 32D. Cell death in the BCR-ABL-expressing clones was preceded by S- and G2/M-phase cell cycle arrest. Activation of FAS/APO-1 and caspase-8 was observed in all the tk-transduced cell lines after GCV treatment. However, the caspase-8 inhibitor Z-IETD-FMK only partially abrogated tk/GCV-induced apoptosis. A possible role for inhibition of Bcl-2 or Bcl-x(L) expression in the apoptosis induced by GCV was observed in the tk-transduced TonB210.1 cells but not in the 32D or 32Dp210 cells. The data demonstrate that expression of the Bcr-Abl oncoprotein does not block the apoptosis induced by the HSV-tk/GCV system, suggesting that this suicide gene therapy strategy could be considered for the treatment of CML in blast crisis.

Animals↗

PubMed2001

Elimination of the truncated message from the herpes simplex virus thymidine kinase suicide gene.

Introduction of the Herpes simplex virus thymidine kinase (HSV-tk) gene into target cells renders them susceptible to killing by ganciclovir (GCV). We are studying the use of HSV-tk-transduced T lymphocytes in the context of hematopoietic stem cell transplantation. We have previously shown, in vitro and in vivo, the occurrence of transduced cells resistant to GCV due to a deletion within HSV-tk. This deletion, a consequence of the presence of cryptic splice donor and acceptor sites, originates in the retroviral producer cell. Here we adopt two different methods that introduce third-base degenerate changes at the cryptic splice sites and so prevent splicing. Consequently, the HSV-tk protein is unaltered and the sensitivity of the target cells to GCV is preserved. The use of this mutated HSV-tk should reduce the likelihood of the development of resistant genetically modified cells during clinical trials.

Antiviral Agents↗

PubMed2001

Cytomegalovirus seropositivity adversely influences outcome after T-depleted unrelated donor transplant in patients with chronic myeloid leukaemia: the case for tailored graft-versus-host disease prophylaxis.

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after haematopoietic stem cell transplantation from matched unrelated donors (MUD). The role of T-cell depletion (TCD) as a strategy to prevent GVHD is controversial because of the associated increased risk of leukaemic relapse, graft failure and delayed immune reconstitution. The demonstration that donor lymphocyte infusion (DLI) is effective salvage therapy if patients relapse after transplantation for chronic myeloid leukaemia (CML) prompted us to examine the proposal that TCD may be a form of GVHD prophylaxis particularly suited to this disease in patients undergoing MUD transplantation. We analysed the outcome of 106 consecutive patients with CML in first chronic phase who underwent MUD transplantation. Patients were conditioned with cyclophosphamide and total body irradiation (TBI), and received in vivo TCD, using CD52 monoclonal antibody, as GVHD prophylaxis. Donor lymphocytes were infused at the time of leukaemic relapse. The projected survival at 5 years for all patients was 52.6%. The probability of developing severe acute GVHD (grade 3 or 4) was 14.5%. The only significant predictor of overall survival in univariate and multivariate analysis was patient cytomegalovirus (CMV) serostatus: in CMV-negative patients survival at 5 years was 60% vs. 42% in CMV-positive patients (P = 0.006). The use of TCD was associated with an increased risk of relapse (62% probability at 5 years after transplant), but 80% of patients who received DLI achieved molecular remission that was durable in all but two cases. In vivo TCD, in conjunction with DLI at relapse, is a valuable GVHD prophylactic regimen in CMV-seronegative recipients of MUD allografts, but in CMV-seropositive patients this approach is associated with an increased non-relapse mortality. Consequently, GVHD prophylactic regimens in MUD transplantation should be tailored according to the patient and donor pretransplant characteristics.

Adolescent↗

PubMed2001

Immune neutropenia associated with anti-human neutrophil antigen-2a (NB1) antibodies following unrelated donor stem cell transplantation for chronic myeloid leukaemia: perpetuation by granulocyte colony-stimulating factor.

A case of immune neutropenia following unrelated stem cell transplantation for chronic myeloid leukaemia is described. The neutropenia developed following herpes zoster viral infection and was associated with antibodies to the human neutrophil antigen (HNA)-2a (formerly known as NB1). The neutropenia was prolonged, profound and unresponsive to granulocyte colony-stimulating factor (GCSF). The neutrophil count recovered after GCSF was discontinued. HNA-2a has been reported to be upregulated following GCSF administration. In the present case, it appears that the immune neutropenia may have been perpetuated by GCSF administration.

Adult↗

PubMed2001

T-cell depletion and autologous stem cell transplantation in the management of tumour stage mycosis fungoides with peripheral blood involvement.

Nine patients with tumour stage mycosis fungoides (MF) have been entered into a pilot study of T-cell depletion and autologous stem cell transplantation (SCT). Eight patients had detectable rearrangements of the T-cell receptor (TCR) gamma-gene demonstrated by polymerase chain reaction (PCR)/single-stranded conformation polymorphism (SSCP) in the peripheral blood. The median age was 47 years and the median duration of disease before SCT was 61 months; Peripheral blood progenitor cells were mobilized using high-dose etoposide (1.6 g/m2) and granulocyte colony-stimulating factor (G-CSF). The apheresis products underwent rigorous T-cell depletion with immunomagnetic methods. Double CD34-positive and CD4/CD8-negative selection achieved a median reduction of 3.89 log of T cells. All nine patients have been transplanted. Conditioning included carmustine (BCNU), etoposide and melphalan (BEM) in seven patients and total body irradiation plus etoposide or melphalan in two. Eight patients engrafted promptly and one patient died of septicaemia. All survivors entered complete remission. Seven patients have relapsed at a median of 7 months (2-14) post SCT. However, most patients have relapsed into a less aggressive stage, which has responded to conventional therapy. Four out of seven evaluable patients had detectable TCR rearrangements in the T-cell depleted graft. A T-cell clone was also detected in the peripheral blood before relapse in four cases. Autologous SCT is feasible, safe and can result in complete remission in a significant proportion of patients with tumour stage mycosis fungoides. Despite a short relapse-free survival, most patients achieved good disease control at the time of relapse.

Adult↗

PubMed2001

Pharmacokinetics of CAMPATH-1H in BMT patients.

BACKGROUND: CAMPATH-1 (CD52)Abs are used in stem-cell transplantation for prevention of GvHD and rejection. The humanized Ab CAMPATH1H has recently replaced the rat Ab CAMPATH-1G. There was a concern whether it might have a longer half-life in vivo and, possibly, cause prolonged immunosuppression post-transplant. METHODS: Serum samples were collected pre- and post-transplant from patients receiving CAMPATH-1H at 10 mg/day according to two protocols: (A) from Day -5 to Day +4 (total dose, 100 mg), (B) from Day -10 to Day -6 (total dose, 50 mg). The Ab concentrations were measured using an immunofluorescence assay. RESULTS: Lymphocytes were substantially depleted by the second day of treatment and were below 0.1 x 10(9)/L by the day of transplant and for at least 1 month post-transplant. By Day 90 there was a greater recovery in Group B, to a median of 0.32 x 10(9)/L compared with 0.25 x 10(9)/L in Group A. By Day 180, both groups had recovered to approx 0.52 x 10(9)/L. Serum concentrations of CAMPATH-1H on the day of transplant were well above the level necessary for opsonization of lymphocytes. The peak Ab concentration was 6.1 micro g/mL in Group A and 2.5 micro g/mL in Group B. CAMPATH-1H could be detected in Group A for 23 days post-transplant, significantly longer than in Group B (11 days). The terminal half-life in the two groups was similar (range 15-21 days) and contrasts with the half-life of < 1 day previously estimated for CAMPATH-1G. There were no cases of graft failure and the incidence of GvHD was similar in the two groups. DISCUSSION: The humanized Ab CAMPATH-1H appears to persist in the circulation for longer than the original rat Ab CAMPATH-1G. This might contribute to delayed lymphocyte recovery and prohibit the use of early donor-lymphocyte infusions. A short course of treatment given early pre-transplant is likely to be preferable to the extended course given both pre- and post-transplant.

Adult↗

PubMed2000

Durability of responses following donor lymphocyte infusions for patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia.

An analysis was performed of the response to treatment with donor lymphocyte infusions (DLI) and the survival in 66 consecutive patients who relapsed after primary treatment by allogeneic stem cell transplantation for BCR-ABL-positive chronic myeloid leukemia. The transplant donor was an HLA-identical sibling (n = 35) or a "matched" unrelated volunteer (n = 31). Fifty-seven patients were transplanted in chronic phase, eight in accelerated phase, and one in second chronic phase. The recognition of relapse was based on precise molecular, cytogenetic, or hematologic criteria. The median interval from transplant to relapse was 12 months (range 3-85). The median interval from relapse to initiation of DLI was 9.4 months (range 1-70). Patients received DLI from their original transplant donors on a bulk-dose (n = 34) or on an escalating-dose (n = 32) regimen. Patients were monitored serially by hematologic, cytogenetic, and molecular criteria. Molecular remission was defined by the finding of negative results by nested primer reverse transcriptase polymerase chain reaction (RT-PCR) for BCR-ABL transcripts on two consecutive occasions, subject to satisfactory controls. Forty-four patients (67%) achieved molecular remission. Patients who had relapsed to advanced phase disease and patients with short intervals between transplant and relapse had significantly lower probabilities of achieving molecular remission. Of the 44 patients who achieved molecular remission, 4 reverted to a PCR-positive status at 15, 18, 37, and 87 weeks after remission. The probability of survival for patients who achieved molecular remission was significantly better than for those who failed to do so (95% versus 53% at 3 years post-DLI, P = .0001). We conclude that the majority of molecular remissions after DLI are durable, and thus the majority of responding patients may prove to have been cured. (Blood. 2000;96:2712-2716)

Adult↗

PubMed2000

Estimating leukemia-free survival after allografting for chronic myeloid leukemia: a new method that takes into account patients who relapse and are restored to complete remission.

A significant number of patients who relapse after allogeneic stem cell transplantation (SCT) for chronic myeloid leukemia (CML) will achieve sustained remissions after treatment with interferon-alpha, second transplants, or donor lymphocyte infusions (DLI) from the original stem cell donor. Because leukemia-free survival (LFS) is at present defined as survival without evidence of relapse at any time posttransplant, patients who relapse but are then restored to complete remission are treated as failures when estimating LFS. We have established a new category of LFS, termed current LFS (CLFS), which we define as survival without evidence of leukemia at the time of most recent assessment. To gauge the contribution of treatment for relapse to the efficacy of allogeneic SCT in the management of CML in chronic phase, we compared conventional LFS and CLFS in 189 consecutive patients who underwent SCT over a 7-year period with a minimum follow-up of 3 years. Patients with sibling donors (n = 111) received cyclosporine and methotrexate as prophylaxis for graft versus host disease; patients with unrelated donors (n = 78) also received Campath-1G or 1H as intravenous T-cell depletion. The 5-year LFS defined conventionally was 36% (CI: 29% to 43%) versus a 5-year CLFS of 49% (CI: 36% to 62%). This new method of defining LFS confirms the view that appropriate "salvage" therapy, principally DLI, makes a major contribution to the capacity of allogeneic SCT to produce long-term LFS in patients who receive SCT for CML and emphasizes the importance of redefining LFS to take account of successful treatment of relapse.

Adolescent↗

PubMed2000

Characterization of recombination events leading to the production of an ecotropic replication-competent retrovirus in a GP+envAM12-derived producer cell line.

Replication-competent retrovirus (RCR) was identified in a GP+envAM12-derived producer cell, containing the MFG-S-Neo retroviral vector, using a marker rescue assay. Studies were undertaken to determine the origin and structure of this RCR. Receptor interference assays demonstrated that the virus was pseudotyped with an ecotropic envelope. Molecular analysis demonstrated the presence of a MoMLV ecotropic env recombinant where the neomycin resistance gene of the MFG-S-Neo vector was replaced by MoMLV ecotropic env. Additional recombinants linking the retroviral pol gene to neo and the neo gene to MoMLV env were also identified. A full-length MoMLV retroviral genome was detected by nested PCR in the contaminated amphotropic producer cells and in cells infected with its supernatant. Unexpectedly, this was also present in the GP+E86 packaging cells together with a previously undescribed envelope construct possessing a full 5' and 3' LTR, although these cells were consistently negative for the presence of RCR. These anomalies in the GP+E86 packaging cell line result in increased homology with the MFG-S-Neo vector, leading to an increased risk for the production of RCR. Our findings point to a need for increased vigilance when using these packaging lines to generate replication-defective retrovirus.

Base Sequence↗

PubMed2000

Comparison of single-dose and escalating-dose regimens of donor lymphocyte infusion for relapse after allografting for chronic myeloid leukemia.

Donor lymphocyte infusion (DLI) was originally administered as a single, relatively large dose of lymphocytes called a bulk dose regimen (BDR). It has since been suggested that the use of an escalating dose regimen (EDR) may be equally effective against leukemia while it induces less graft-versus-host disease (GVHD). We therefore compared the efficacy and incidence of complications in a nonrandomized sequential study of the 2 regimens in 48 consecutive patients who had relapses with cytogenetic or hematologic evidence of chronic myeloid leukemia after allogeneic stem cell transplantation. Twenty-eight patients were treated on a BDR (August 1990 to November 1995) and 20 were treated on an EDR (December 1995 to January 1998). Although the probability of achieving cytogenetic remission within 2 years of starting DLI did not differ significantly between the 2 groups (EDR, 91% [CI, 63%-98%] vs. BDR, 67% [CI,49%-83%], P =.70), the incidence of GVHD was much lower using EDR (10% vs. 44%, P =.011). When we considered only subsets of patients treated by BDR or EDR who had received comparable total lymphoid cell doses, the incidence and severity of acute and chronic GVHD were both significantly lower for recipients treated by EDR than for recipients treated by BDR (P =.005 and P =.031, respectively). These findings suggest that the incidence of GVHD associated with the EDR is low, not because the final cell dose is small, but because lymphocytes are administered over a considerable number of months. (Blood. 2000;95:67-71)

Disease-Free Survival↗

PubMed2000

Ex vivo expansion and characterisation of CD34+ cells derived from chronic myeloid leukaemia bone marrow and peripheral blood, and from normal bone marrow and mobilised peripheral blood.

Ex vivo culture of CD34+ has the potential to provide large numbers of cells for clinical use in autologous and allogeneic transplantation and for experimental research involving genetic manipulation. We evaluated the ex vivo expansion of CD34+ cells obtained from bone marrow (BM) and peripheral blood (PB) of untreated patients with chronic myeloid leukaemia (CML) in the chronic phase and compared these results with those obtained from BM from normal volunteers (NBM) and peripheral blood after mobilising chemotherapy from patients with non-haematological disorders (MPB). Selected CD34+ cells were stimulated with interleukin 1(beta), interleukin IL-3, interleukin IL-6 and stem cell factor. The proliferation observed in patients with CML was similar to that seen in normal donors. CD34+ cells derived from patients with CML are more differentiated than their normal counterparts, as shown by the coexpression of CD34 and CD33 antigens on day 0 (85.6% for CML-BM and 76.8% for CML-PB). The culture conditions allowed a significant expansion of granulocyte-macrophage colony-forming units (CFU-GM) from NBM (33-fold increase) and MPB (22-fold increase), in contrast with CML-derived BM and PB CD34+ cells (2.3-fold increase). These results indicate that the optimal time to harvest ex vivo expanded cells is dependent on a critical compromise between cell numbers and successful retention of their repopulating potential.

Antigens, CD34↗

PubMed2000

Absence of in vitro or in vivo bystander effects in a thymidine kinase-transduced murine T lymphoma.

Among the goals of an optimal gene transfer system are a predictably high efficiency of transfer and the ability to confer stable gene expression. An additional benefit of strategies designed to target tumor or effector cells could be the induction of a bystander effect. Although tumor killing by the bystander effect in vivo has been obtained in several types of malignant tumors, it has not been reported for T lymphomas. The goals of this work were to determine the stability of the expression of the herpes simplex virus type-1 thymidine kinase and the low-affinity receptor for nerve growth factor truncated of its intracellular domain (deltaLNGFR) genes inserted in a murine T lymphoma; in addition, we sought to determine whether a bystander effect (direct or indirect) was present after treatment of the transduced tumor with ganciclovir. This study demonstrates a high level of stable expression of both genes in the T lymphoma in vitro and in vivo. However, we could not detect direct or indirect bystander effects in vivo mediated by the herpes simplex virus thymidine kinase/ganciclovir system in this tumor of lymphocyte origin. This is the first report to investigate bystander effects in vivo on a T-cell lineage tumor; in addition, this report has implications for the therapeutic transfer of non-transformed, antigen-specific T cells in vivo.

Animals↗

PubMed2000

HLA-DR4 is associated with a diminished risk of the development of chronic myeloid leukemia (CML). Chronic Leukemia Working Party of the European Blood and Marrow Transplant Registry.

CML is characterized by the chromosomal translocation t(9;22) (q34;q11) resulting in the chimeric bcr-abl oncogene that encodes P210 fusion proteins with novel amino acid sequences in the breakpoint region. If these peptides derived from P210 are presented by HLA molecules on the cell membrane of leukemic cells an immunological response may occur. Recent studies using synthetic peptides identical to the bcr-abl fusion region revealed that some peptides are capable of binding to the class I molecules HLA-A2,-A3,-A11 and -B8 and the class II molecules HLA-DR1, -DR2, -DR3, -DR4 and -DR11. Moreover T cell responses have been induced against bcr-abl-derived synthetic peptides bound to some of these HLA molecules. For HLA class I, we have previously shown that individuals expressing HLA-A3 and -B8 have a diminished risk of development of CML. To assess a similar protective effect of class II molecules we performed a large multi-center study. This study compared the frequencies of HLA-DR1, -DR2, -DR3, -DR4 and -DR11 of patients with CML from the database of the EBMT (n = 1462) with unaffected individuals from the registry of Bone Marrow Donors Worldwide (n = 500 596). Patients and controls were matched per country. This analysis yielded significantly lower odds ratios (ORs) of 0.86 (95% CI 0.75-0.98) for HLA-DR3 and of 0.80 (95% CI 0.71-0.89) for HLA-DR4. The OR was 0.91 (95% CI 0.80-1.04) for HLA-DR1, 1.05 (95% CI 0.94-1.18) for HLA-DR2 and 0.87 (95% CI 0.74-1.01) for HLA-DR11. To assess a possible effect of the linkage disequilibrium between HLA-B8 and HLA-DR3 we found that coexpression of HLA-B8 and HLA-DR3 gave an OR of 0.84 (95% CI 0.72-0.98), whereas HLA-DR3 positive/HLA-B8 negative individuals showed an OR of 1.02 (95% CI 0.84-1.24). This means that the protective effect of HLA-DR3 of the development of CML was probably caused by its linkage disequilibrium with HLA-B8. In contrast, as there is no linkage disequilibrium of HLA-DR4 with HLA-A3 or HLA-B8, the results indicate that HLA-DR4 expression itself is associated with a diminished incidence of CML possibly by the presentation of bcr-abl breakpoint peptides in these HLA molecules on the membrane of the leukemic cells.

Bone Marrow Transplantation↗