Safety and efficacy of autologous haematopoietic stem-cell transplantation with low-dose cyclophosphamide mobilisation and reduced intensity conditioning versus standard of care in refractory Crohn's disease (ASTIClite): an open-label, multicentre, randomised controlled trial

BACKGROUND

A previous controlled trial of autologous haematopoietic stem-cell transplantation (HSCT) in patients with refractory Crohn's disease did not meet its primary endpoint and reported high toxicity. We aimed to assess the safety and efficacy of HSCT with an immune-ablative regimen of reduced intensity versus standard of care in this patient population.

METHODS

This open-label, multicentre, randomised controlled trial was conducted in nine National Health Service hospital trusts across the UK. Adults (aged 18-60 years) with active Crohn's disease on endoscopy (Simplified Endoscopic Score for Crohn's Disease [SES-CD] ulcer sub-score of ≥2) refractory to two or more classes of biological therapy, with no perianal or intra-abdominal sepsis or clinically significant comorbidity, were recruited. Participants were centrally randomly assigned (2:1) to either HSCT with a reduced dose of cyclophosphamide (intervention group) or standard care (control group). Randomisation was stratified by trial site by use of random permuted blocks of size 3 and 6. Patients in the intervention group underwent stem-cell mobilisation (cyclophosphamide 1 g/m2 with granulocyte colony-stimulating factor (G-CSF) 5 μg/kg) and stem-cell harvest (minimum 2·0 × 106 CD34+ cells per kg), before conditioning (fludarabine 125 mg/m2, cyclophosphamide 120 mg/kg, and rabbit anti-thymocyte globulin [thymoglobulin] 7·5 mg/kg in total) and subsequent stem-cell reinfusion supported by G-CSF. Patients in the control group continued any available conventional, biological, or nutritional therapy. The primary outcome was absence of endoscopic ulceration (SES-CD ulcer sub-score of 0) without surgery or death at week 48, analysed in the intention-to-treat population by central reading. This trial is registered with the ISRCTN registry, 17160440.

FINDINGS

Between Oct 18, 2018, and Nov 8, 2019, 49 patients were screened for eligibility, of whom 23 (47%) were randomly assigned: 13 (57%) to the intervention group and ten (43%) to the control group. In the intervention group, ten (77%) participants underwent HSCT and nine (69%) reached 48-week follow-up; in the control group, nine (90%) reached 48-week follow-up. The trial was halted in response to nine reported suspected unexpected serious adverse reactions in six (46%) patients in the intervention group, including renal failure due to proven thrombotic microangiopathy in three participants and one death due to pulmonary veno-occlusive disease. At week 48, absence of endoscopic ulceration without surgery or death was reported in three (43%) of seven participants in the intervention group and in none of six participants in the control group with available data. Serious adverse events were more frequent in the intervention group (38 in 13 [100%] patients) than in the control group (16 in four [40%] patients). A second patient in the intervention group died after week 48 of respiratory and renal failure.

INTERPRETATION

Although HSCT with an immune-ablative regimen of reduced intensity decreased endoscopic disease activity, significant adverse events deem this regimen unsuitable for future clinical use in patients with refractory Crohn's disease.

FUNDING

Efficacy and Mechanism Evaluation Programme, a Medical Research Council and National Institute for Health Research partnership.

Posttransplant MRD and T-cell chimerism status predict outcomes in patients who received allografts for AML/MDS

Allogeneic stem-cell transplant allows for the delivery of curative graft-versus-leukemia (GVL) in patients with acute myeloid leukemia/myelodysplasia (AML/MDS). Surveillance of T-cell chimerism, measurable residual disease (MRD) and blast HLA-DR expression may inform whether GVL effectiveness is reduced. We report here the prognostic impact of these biomarkers in patients allografted for AML/MDS. One hundred eighty-seven patients from FIGARO, a randomized trial of reduced-intensity conditioning regimens in AML/MDS, were alive and relapse-free at the first MRD time-point and provided monitoring samples for flow cytometric MRD and T-cell chimerism, requested to month+12. Twenty-nine (15.5%) patients had at least 1 MRD-positive result posttransplant. MRD-positivity was associated with reduced overall survival (OS) (hazard ratio [HR], 2.18; P = .0028) as a time-varying Cox variable and remained significant irrespective of pretransplant MRD status in multivariate analyses (P < .001). Ninety-four patients had sequential MRD with T-cell chimerism results at months+3/+6. Patients with full donor T-cell chimerism (FDTC) had an improved OS as compared with patients with mixed donor T-cell chimerism (MDTC) (adjusted HR=0.4; P = .0019). In patients with MDTC (month+3 or +6), MRD-positivity was associated with a decreased 2-year OS (34.3%) vs MRD-negativity (71.4%) (P = .001). In contrast, in the group with FDTC, MRD was infrequent and did not affect the outcome. Among patients with posttransplant MRD-positivity, decreased HLA-DR expression on blasts significantly reduced OS, supporting this as a mechanism for GVL escape. In conclusion, posttransplant MRD is an important predictor of the outcome in patients allografted for AML/MDS and is most informative when combined with T-cell chimerism results, underlining the importance of a GVL effect in AML/MDS.

Real world reduction in red cell transfusion with restrictive transfusion threshold in haematology inpatients

OBJECTIVES

The aim of this study was to assess the reduction in red cell transfusions following a change in the red cell transfusion threshold for haematology inpatients from 80 to 70 g/L.

BACKGROUND

Haematology patients are among the high users of red blood cells. We reduced the threshold for transfusion of haematology inpatients to 70 g/L. This was based on evidence provided by randomised controlled trial published in 2020 that showed restrictive transfusion is non-inferior to liberal transfusion.

METHOD

We assessed red cell transfusions for haematology inpatients at Oxford University Hospitals NHS Foundation Trust for 9 months before and 9 months after a change in red cell transfusion threshold from 80 to 70 g/L.

RESULTS

After the change in threshold to 70 g/L or less from 80 g/L, the median number of red cell transfusions per month reduced to 88 from 111. This was a 23% reduction in the total number of red cells administered per month.

CONCLUSION

These results show the real-world reductions in transfusion that can be made by putting local transfusion guidelines in line with the international recommendations. This is of particular importance at a time of national blood shortage.

Impaired humoral and cellular response to primary COVID-19 vaccination in patients less than 2 years after allogeneic bone marrow transplant

Allogeneic haematopoietic stem cell transplant (HSCT) recipients remain at high risk of adverse outcomes from coronavirus disease 2019 (COVID-19) and emerging variants. The optimal prophylactic vaccine strategy for this cohort is not defined. T cell-mediated immunity is a critical component of graft-versus-tumour effect and in determining vaccine immunogenicity. Using validated anti-spike (S) immunoglobulin G (IgG) and S-specific interferon-gamma enzyme-linked immunospot (IFNγ-ELIspot) assays we analysed response to a two-dose vaccination schedule (either BNT162b2 or ChAdOx1) in 33 HSCT recipients at ≤2 years from transplant, alongside vaccine-matched healthy controls (HCs). After two vaccines, infection-naïve HSCT recipients had a significantly lower rate of seroconversion compared to infection-naïve HCs (25/32 HSCT vs. 39/39 HCs no responders) and had lower S-specific T-cell responses. The HSCT recipients who received BNT162b2 had a higher rate of seroconversion compared to ChAdOx1 (89% vs. 74%) and significantly higher anti-S IgG titres (p = 0.022). S-specific T-cell responses were seen after one vaccine in HCs and HSCT recipients. However, two vaccines enhanced S-specific T-cell responses in HCs but not in the majority of HSCT recipients. These data demonstrate limited immunogenicity of two-dose vaccination strategies in HSCT recipients, bolstering evidence of the need for additional boosters and/or alternative prophylactic measures in this group.

Pruritic rash following haploidentical stem cell transplantation

A woman who had undergone haematopoietic stem cell transplantation presented with cutaneous features suggestive of graft-versus-host disease. Histopathological examination revealed a diffuse dermal infiltration of atypical monomorphic cells with a high proliferative index. Immunohistochemistry revealed positivity for monocytic markers, but negativity for T-cell markers.

Augmented Reduced-Intensity Regimen Does Not Improve Postallogeneic Transplant Outcomes in Acute Myeloid Leukemia

PURPOSE

Reduced-intensity conditioning (RIC) regimens have extended the curative potential of allogeneic stem-cell transplantation to older adults with high-risk acute myeloid leukemia (AML) and myelodysplasia (MDS) but are associated with a high risk of disease relapse. Strategies to reduce recurrence are urgently required. Registry data have demonstrated improved outcomes using a sequential transplant regimen, fludarabine/amsacrine/cytarabine-busulphan (FLAMSA-Bu), but the impact of this intensified conditioning regimen has not been studied in randomized trials.

PATIENTS AND METHODS

Two hundred forty-four patients (median age, 59 years) with high-risk AML (n = 164) or MDS (n = 80) were randomly assigned 1:1 to a fludarabine-based RIC regimen or FLAMSA-Bu. Pretransplant measurable residual disease (MRD) was monitored by flow cytometry (MFC-MRD) and correlated with outcome.

RESULTS

There was no difference in 2-year overall survival (hazard ratio 1.05 [85% CI, 0.80 to 1.38] P = .81) or cumulative incidence of relapse (CIR) (hazard ratio 0.94 [95%CI, 0.60 to 1.46] P = .81) between the control and FLAMSA-Bu arms. Detectable pretransplant MFC-MRD was associated with an increased CIR (2-year CIR 41.0% v 20.0%, P = .01) in the overall trial cohort with a comparable prognostic impact when measured by an unsupervised analysis approach. There was no evidence of interaction between MRD status and conditioning regimen intensity for relapse or survival. Acquisition of full donor T-cell chimerism at 3 months abrogated the adverse impact of pretransplant MRD on CIR and overall survival.

CONCLUSION

The intensified RIC conditioning regimen, FLAMSA-Bu, did not improve outcomes in adults transplanted for high-risk AML or MDS regardless of pretransplant MRD status. Our data instead support the exploration of interventions with the ability to accelerate acquisition of full donor T-cell chimerism as a tractable strategy to improve outcomes in patients allografted for AML.

Red cell transfusion in outpatients with myelodysplastic syndromes: a feasibility and exploratory randomised trial

Optimal red cell transfusion support in myelodysplastic syndromes (MDS) has not been tested and established. The aim of this study was to demonstrate feasibility of recruitment and follow-up in an outpatient setting with an exploratory assessment of quality of life (QoL) outcomes (EORTC QLQ-C30 and EQ-5D-5L). We randomised MDS patients to standardised transfusion algorithms comparing current restrictive transfusion thresholds (80 g/l, to maintain haemoglobin 85-100 g/l) with liberal thresholds (105 g/l, maintaining 110-125 g/l). The primary outcomes were measures of compliance to transfusion thresholds. Altogether 38 patients were randomised (n = 20 restrictive; n = 18 liberal) from 12 participating sites in UK, Australia and New Zealand. The compliance proportion for the intention-to-treat population was 86% (95% confidence interval 75-94%) and 99% (95-100%) for restrictive and liberal arms respectively. Mean pre-transfusion haemoglobin concentrations for restrictive and liberal arms were 80 g/l (SD6) and 97 g/l (SD7). The total number of red cell units transfused on study was 82 in the restrictive and 192 in the liberal arm. In an exploratory analysis, the five main QoL domains were improved for participants in the liberal compared to restrictive arm. Our findings support the feasibility and need for a definitive trial to evaluate the effect of different red cell transfusion thresholds on patient-centred outcomes.

Provision of cellular blood components to CMV-seronegative patients undergoing allogeneic stem cell transplantation in the UK: survey of UK transplant centres

OBJECTIVES

To identify current UK practice with regards to provision of blood components for cytomegalovirus (CMV)-seronegative, potential, allogeneic stem cell recipients of seronegative grafts.

BACKGROUND

Infection with CMV remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (aSCT). CMV transmission has been a risk associated with the transfusion of blood components from previously exposed donors, but leucocyte reduction has been demonstrated to minimise this risk. In 2012, the UK Advisory Committee for the Safety of Tissues and Organs (SaBTO) recommended that CMV-unselected components could be safely transfused without increased risk of CMV transmission.

METHODS

We surveyed UK aSCT centres to establish current practice.

RESULTS

Fifteen adult and seven paediatric centres (75%) responded; 22·7% continue to provide components from CMV-seronegative donors. Reasons cited include the continued perceived risk of CMV transmission by blood transfusion, its associated morbidity and concerns regarding potential for ambiguous CMV serostatus in seronegative potential transplant recipients due to passive antibody transfer from CMV-seropositive blood donors, leading to erroneous donor/recipient CMV matching at transplant.

CONCLUSIONS

The survey demonstrated a surprisingly high rate (22.7%) of centres continuing to provide blood components from CMV-seronegative donors despite SaBTO guidance.

Allogeneic haematopoietic stem cell transplant in patients with lower risk myelodysplastic syndrome: a retrospective analysis on behalf of the Chronic Malignancy Working Party of the EBMT

This corrects the article DOI: 10.1038/bmt.2016.266.

Genetically distinct leukemic stem cells in human CD34- acute myeloid leukemia are arrested at a hemopoietic precursor-like stage

Quek and colleagues identify human leukemic stem cells (LSCs) present in CD34⁻ AML. In-depth characterization of the functional and clonal aspects of CD34⁻ LSCs indicates that most are similar to myeloid precursors.

Our understanding of the perturbation of normal cellular differentiation hierarchies to create tumor-propagating stem cell populations is incomplete. In human acute myeloid leukemia (AML), current models suggest transformation creates leukemic stem cell (LSC) populations arrested at a progenitor-like stage expressing cell surface CD34. We show that in ∼25% of AML, with a distinct genetic mutation pattern where >98% of cells are CD34⁻, there are multiple, nonhierarchically arranged CD34⁺ and CD34⁻ LSC populations. Within CD34⁻ and CD34⁺ LSC–containing populations, LSC frequencies are similar; there are shared clonal structures and near-identical transcriptional signatures. CD34⁻ LSCs have disordered global transcription profiles, but these profiles are enriched for transcriptional signatures of normal CD34⁻ mature granulocyte–macrophage precursors, downstream of progenitors. But unlike mature precursors, LSCs express multiple normal stem cell transcriptional regulators previously implicated in LSC function. This suggests a new refined model of the relationship between LSCs and normal hemopoiesis in which the nature of genetic/epigenetic changes determines the disordered transcriptional program, resulting in LSC differentiation arrest at stages that are most like either progenitor or precursor stages of hemopoiesis.

High proportions of regulatory T cells in PBSC grafts predict improved survival after allogeneic haematopoietic SCT

Regulatory T cells (Tregs) modulate immune responses and improve survival in murine transplant models. However, whether the Treg content of allogeneic cell grafts influences the outcome in human haematopoietic stem cell (HSC) transplantation is not well established. In a prospective study of 94 adult allogeneic PBSC transplants (60% unrelated; 85% reduced intensity conditioning), the median Treg (CD3(+)CD4(+)CD25(+)FOXP3(+)CD127(dim/-)) dose transplanted was 4.7 × 10(6)/kg, with Tregs accounting for a median of 2.96% of CD4(+) T cells. Patients transplanted with grafts containing a Treg/CD4(+) T-cell ratio above the median had a 3-year overall survival of 75%, compared with 49% in those receiving grafts with a Treg/CD4(+) T-cell ratio below the median (P=0.02), with a 3-year non-relapse mortality of 13% and 35%, respectively (P=0.02). In multivariate analysis, a high graft Treg/CD4(+) T-cell ratio was an independent predictor of lower non-relapse mortality (hazard ratio (HR), 0.30; P=0.02), improved overall survival (HR, 0.45; P=0.03) and improved sustained neutrophil (HR, 0.52; P=0.002), platelet (HR, 0.51; P<0.001) and lymphocyte (HR, 0.54; P=0.009) recovery. These data support the hypothesis that the proportion of Tregs in allogeneic HSC grafts influences clinical outcome and suggest that Treg therapies could improve allogeneic HSC transplantation.

Transfusion in CMV seronegative T-depleted allogeneic stem cell transplant recipients with CMV-unselected blood components results in zero CMV transmissions in the era of universal leukocyte reduction: a U.K. dual centre experience

OBJECTIVES

To establish rates of cytomegalovirus (CMV) transmission with use of CMV-unselected (CMV-U), leukocyte-reduced blood components transfused to CMV-seronegative patient/CMV-seronegative donor (CMV neg/neg) allogeneic stem cell transplantation (SCT) recipients including those receiving T-depleted grafts.

BACKGROUND

CMV infection remains a major cause of morbidity following SCT. CMV-seronegative SCT recipients are particularly at risk of transfusion transmitted CMV (TT-CMV) and until recently they have received blood components from CMV-seronegative donors with significant resource implications. Although leukocyte reduction of blood components is reported to minimise risk of TT-CMV, its efficacy in high-risk situations, such as in T-depleted transplant recipients, is unknown.

METHODS

We retrospectively analysed the incidence of TT-CMV in CMV neg/neg allogeneic SCT recipients transfused with CMV-U, leukocyte-reduced blood components in two transplantation centres in the UK. Patients were monitored for CMV infection by weekly CMV polymerase chain reaction testing. Leukocyte reduction of blood components was in accordance with current UK standards.

RESULTS

Among 76 patients, including 59 receiving in vivo T-depletion, no episodes of CMV infection were detected. Patients were transfused with 1442 CMV-unselected, leukocyte-reduced components, equating to 1862 donor exposures.

CONCLUSIONS

Our findings confirm the safety of leukocyte reduction as a strategy in preventing TT-CMV in high-risk allogeneic SCT recipients.

Development of real-time quantitative polymerase chain reaction assays to track treatment response in retinoid resistant acute promyelocytic leukemia

Molecular detection of minimal residual disease (MRD) has become established to assess remission status and guide therapy in patients with ProMyelocytic Leukemia-RARA+ acute promyelocytic leukemia (APL). However, there are few data on tracking disease response in patients with rarer retinoid resistant subtypes of APL, characterized by PLZF-RARA and STAT5b-RARA. Despite their rarity (<1% of APL) we identified 6 cases (PLZF-RARA, n = 5; STAT5b-RARA, n = 1), established the respective breakpoint junction regions and designed reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) assays to detect leukemic transcripts. The relative level of fusion gene expression in diagnostic samples was comparable to that observed in t(15;17) - associated APL, affording assay sensitivities of ∼1 in 10(4)-10(5). Serial samples were available from two PLZF-RARA APL patients. One showed persistent polymerase chain reaction positivity, predicting subsequent relapse, and remains in CR2, ∼11 years post-autograft. The other, achieved molecular remission (CRm) with combination chemotherapy, remaining in CR1 at 6 years. The STAT5b-RARA patient failed to achieve CRm following frontline combination chemotherapy and ultimately proceeded to allogeneic transplant on the basis of a steadily rising fusion transcript level. These data highlight the potential of RT-qPCR detection of MRD to facilitate development of more individualized approaches to the management of rarer molecularly defined subsets of acute leukemia.

Factors predicting long-term survival after T-cell depleted reduced intensity allogeneic stem cell transplantation for acute myeloid leukemia

BACKGROUND

Reduced intensity conditioning regimens permit the delivery of a potentially curative graft-versus-leukemia effect in older patients with acute myeloid leukemia. Although T-cell depletion is increasingly used to reduce the risk of graft-versus-host disease its impact on the graft-versus-leukemia effect and long-term outcome post-transplant is unknown.

DESIGN AND METHODS

We have characterized pre- and post-transplant factors determining overall survival in 168 patients with acute myeloid leukemia transplanted using an alemtuzumab based reduced intensity conditioning regimen with a median duration of follow-up of 37 months.

RESULTS

The 3-year overall survival for patients transplanted in CR1 or CR2/CR3 was 50% (95% CI, 38% to 62%) and 44% (95% CI, 31% to 56%), respectively compared to 15% (95% CI, 2% to 36%) for patients with relapsed/refractory disease. Multivariate analysis demonstrated that both survival and disease relapse were influenced by status at transplant (P=0.008) and presentation cytogenetics (P=0.01). Increased exposure to cyclosporine A (CsA) in the first 21 days post-transplant was associated with an increased relapse risk (P<0.0001) and decreased overall survival (P<0.0001).

CONCLUSIONS

Disease stage, presentation karyotype and post-transplant CsA exposure are important predictors of outcome in patients undergoing a T-cell depleted reduced intensity conditioning allograft for acute myeloid leukemia. These data confirm the presence of a potent graft-versus-leukemia effect after a T-cell depleted reduced intensity conditioning allograft in acute myeloid leukemia and identify CsA exposure as a manipulable determinant of outcome in this setting.

hTERT, the catalytic component of telomerase, is downregulated in the haematopoietic stem cells of patients with chronic myeloid leukaemia

Telomere shortening is associated with disease progression in chronic myeloid leukaemia (CML). To investigate the biology and regulation of telomerase in CML, we evaluated expression of the telomerase components, its regulators and several telomeric-associated proteins. Quantitative real-time-polymerase chain reaction (PCR) was used to compare gene expression in the CD34+/leukaemic blast cells of 22 CML patient samples to the CD34+ cell population of healthy individuals. hTERT, the catalytic component of telomerase, was downregulated in eight of 12 chronic phase (CP) patients (P = 0.0387). Furthermore, hTERT was significantly downregulated in two of three patients in accelerated phase (AP) and seven of seven patients in blast crisis (BC), P = 0.0017. Expression of hTR and telomeric-associated proteins TEP1, TRF1, TRF2, tankyrase and PinX1 was high in the majority of CP and AP patients. With the exceptions of TEP1 and hTR, expression of these factors was highest in CP and decreased during disease progression. Expression of c-Myc, a positive regulator of hTERT transcription, correlated with hTERT expression and decreased with disease progression, falling below control levels in BC. hTERT levels were increased in CP patients following successful treatment with imatinib, relative to untreated CP patients. We suggest that reduced hTERT expression directly causes the shortened telomeres observed in CML.

Allogeneic Stem-Cell Transplantation Using a Reduced-Intensity Conditioning Regimen Has the Capacity to Produce Durable Remissions and Long-Term Disease-Free Survival in Patients With High-Risk Acute Myeloid Leukemia and Myelodysplasia

Purpose

The toxicity of allogeneic stem-cell transplantation can be substantially reduced using a reduced-intensity conditioning (RIC) regimen. This has increased the proportion of patients with myeloid malignancies eligible for allogeneic transplantation. However, the capacity of RIC allografts to produce durable remissions in patients with acute myeloid leukemia (AML) and myelodysplasia (MDS) has not yet been defined, and consequently, the role of RIC allografts in the management of these diseases remains conjectural.

Patients and Methods

Seventy-six patients with high-risk AML or MDS received an allograft using a fludarabine/melphalan RIC regimen incorporating alemtuzumab. The median age of the cohort was 52 years (range, 18 to 71 years).

Results

The 100-day transplantation-related mortality rate was 9%, and no patient developed greater than grade 2 graft-versus-host disease. With a median follow-up of 36 months (range, 13 to 70 months), 27 patients were alive and in remission, with 3-year actuarial overall survival (OS) and disease-free survival (DFS) rates of 41% and 37%, respectively. The 3-year OS and DFS rates of patients with AML in complete remission at the time of transplantation were 48% and 42%, respectively. Disease relapse was the most common cause of treatment failure and occurred at a median time of 6 months after transplantation. All but one patient destined to relapse did so within 24 months of transplantation.

Conclusion

The extended follow-up in this series identifies a high risk of early disease relapse but provides evidence that RIC allografts can produce sustained DFS in a significant number of patients with AML who would be ineligible for allogeneic transplantation with myeloablative conditioning.

Del (9q) AML: clinical and cytological characteristics and prognostic implications

Del (9q) is a recurrent cytogenetic abnormality in acute myeloid leukaemia (AML). We report an analysis of 81 patients with del(9q) as a diagnostic karyotypic abnormality entered into the Medical Research Council AML trials 10, 11 and 12. Patients were divided into three groups: (i) Sole del (9q), 21 patients; (ii) Del(9q) in association with t(8;21), 29 patients; (iii) Del(9q) in association with other cytogenetic abnormalities, 31 patients. Sole del(9q) was associated with a characteristic bone marrow phenotype at diagnosis: a single Auer rod was found in all cases examined. There was also an association with erythroid dysplasia (74%) and granylocytic lineage vacuolation (90%). The incidence of all three of these features was significantly higher (P < 0.05) in the sole del(9q) group compared with control cases lacking del(9q). The overall survival (OS) of all 81 patients was compared with a control group of 1738 patients with normal cytogenetics entered in the same trials over the period of investigation. The 5-year OS for patients with del(9q) was 45%, compared with 35% for the control group (P = 0.09). Patients with del(9q) in association with t(8;21) had a 5-year OS of 75%, which was significantly better than the groups with either sole del(9q) (40%) and del(9q) with other abnormalities (26%; P = 0.008). Karyotyping indicated a common area of deletion in the region 9q21-22, which was present in 94% of cases. It is likely that the deletion of single or multiple tumour suppressor genes located in this region may underlie the pathogenesis of del (9q) AML.

Telomere length shortening in chronic myelogenous leukemia is associated with reduced time to accelerated phase

Telomere shortening is associated with disease evolution in chronic myelogenous leukemia (CML). We have examined the relationship between diagnostic telomere length and outcome in 59 patients with CML who entered into the MRC CMLIII Trial by Southern blot hybridization using the (TTAGGG)(4) probe. Age-adjusted telomere repeat array (TRA) reduction was found to significantly correlate with time from diagnosis to acceleration, such that patients with a larger TRA reduction entered the accelerated phase more rapidly (r = -0.50; P =.008). Cox-regression analysis for this group was suggestive of a relationship between a greater TRA-reduction and a shorter time to acceleration (P =.054). Age-adjusted TRA reduction did not significantly affect either the time to blast crisis or overall survival. Our results show that telomere shortening observed at the time of diagnosis in CML significantly influences the time to progress to the accelerated phase. The measurement of diagnostic TRA may prove to be clinically important in the selection of patients at high risk of disease transformation in CML.

Early PCR-negativity after allogeneic BMT in adults with t(4;11) ALL in the absence of acute or chronic GVHD

Acute lymphoblastic leukaemia (ALL) with the t(4;11) translocation has a very poor prognosis following conventional chemotherapy. Many patients are offered an allogeneic BMT in first remission. We report on the impact of allogeneic BMT on three patients with t(4;11) ALL in first remission. Median age was 20 years. One patient received marrow from an HLA-identical sibling and the other two from unrelated donors. All three engrafted and none of the patients developed acute or chronic GVHD. Remission status was monitored using a sensitive nested RT-PCR to detect the ALL-1/AF-4 hybrid transcript. All three were PCR-negative at 3 months post-BMT. One of the unrelated recipients died of a fungal infection 4 months post-BMT. The other two are alive and in molecular remission at 21 and 24 months post-BMT. This is the first report of longitudinal follow-up of t(4;11) ALL post-allogeneic BMT by PCR. The early attainment of molecular remission in the absence of GVHD suggests that the conditioning regimen may have been more important than a graft-versus-leukaemia effect in these patients. Follow-up of larger numbers of patients will be required to confirm these preliminary observations.

The effect of experimental epilepsy induced by injection of tetanus toxin into the amygdala of the rat on eating behaviour and response to novelty

A minute dose of tetanus toxin injected into the amygdala of rats produced an apparently reversible epileptiform syndrome similar to that previously described after injection of the toxin into the hippocampus. During the active epilepsy the toxin-injected rats occasionally exhibited 'paroxysmal eating' and also sometimes ran round in circles attempting to bite their own tails. When presented with a novel but palatable food (chocolate buttons or harvest crunch) the toxin-injected rats showed less neophobia than their controls--they ate sooner and ate more. This was found both during the active epilepsy and several weeks later when they had recovered. A similar effect of amygdala injections was found in a second experiment, in which the effect was compared with that of toxin injection in the hippocampus. These rats were tested also on the playground maze on their approach response to a neutral novel object (in a familiar environment in the context of seven familiar objects). The amygdala rats did not show any increase in their novelty response; thus their reduction in neophobia was specific to an appetitive behaviour. In contrast, the hippocampally-injected rats did not exhibit a novelty response in the playground maze, but showed normal neophobia to a new food.