Some text in this abstract has been reproduced from Lindsay J, Din S, Hawkey C, Hind D, Irving P, Lobo A, et al. OFR-9 An RCT of autologous stem-cell transplantation in treatment refractory Crohn’s disease (low-intensity therapy evaluation): ASTIClite. Gut 2021;70(Suppl. 4):A4. Background Treatment-refractory Crohn’s disease is characterised by chronic symptoms, poor quality of life and high costs to the NHS, and through days of work lost by patients. A previous trial of autologous haematopoietic stem cell transplant (HSCT) failed its end point of medication-free clinical remission for 3 months with no evidence of disease activity, and reported high toxicity. Subsequent studies suggest that HSCT achieves complete mucosal healing in 50% of patients, and that toxicity likely relates to the cyclophosphamide dose. Objectives The primary objective was to assess the efficacy of HSCTlite (HSCT with low-dose cyclophosphamide) compared with standard care for inducing regression of intestinal ulceration in patients with refractory Crohn’s disease at week 48. Secondary objectives included the assessment of disease activity, quality of life and regimen safety. Mechanistic objectives included immune reconstitution after HSCTlite. Design Two-arm, parallel-group randomised controlled trial with a 2 : 1 (intervention : control) allocation ratio. Setting Nine NHS trusts (eight trusts were recruitment sites; one trust was a treatment-only site). Participants Adults with treatment-refractory Crohn’s disease, for whom surgery was inappropriate or who had declined surgery. Interventions The intervention treatment was HSCTlite using cyclophosphamide, and the control was any current available treatment for Crohn’s disease, apart from stem cell transplantation. Main outcomes The primary outcome was treatment success at week 48 [mucosal healing (Simple Endoscopic Score for Crohn’s Disease ulcer subscore of 0) without surgery or death], assessed by central readers blinded to allocation and timing of assessment. Key secondary outcomes were clinical remission, Simple Endoscopic Score for Crohn’s Disease scores at week 48, change in Crohn’s Disease Activity Index scores and safety. Results The trial was halted owing to Suspected unexpected serious adverse events that took place after randomising 23 patients (HSCTlite arm, n = 13; usual-care arm, n = 10). Ten out of the 13 patients randomised to the HSCTlite arm received the intervention and nine (one death) reached the 48-week follow-up. In the usual-care arm 9 out of the 10 patients randomised reached the 48-week follow-up (one ineligible). The primary outcome was available for 7 out of 10 HSCTlite patients (including the patient who died) and six out of nine usual-care patients. Absence of endoscopic ulceration without surgery or death was reported in three out of seven (43%) HSCTlite patients, compared with zero out of six (0%) usual-care patients. Centrally read Simple Endoscopic Score for Crohn’s Disease scores [mean (standard deviation)] were 10.8 (6.3) and 10.0 (6.1) at baseline, compared with 2.8 (2.9) and 18.7 (9.1) at week 48, in the HSCT and usual-care arms, respectively. Clinical remission (Crohn’s Disease Activity Index scores of < 150) occurred in 57% and 17% of patients in the HSCTlite and usual-care arms, respectively, at week 48. Serious adverse events were more frequent in the HSCTlite arm [38 in 13 (100%) patients] than in the usual-care arm [16 in 4 (40%) patients]. Nine suspected unexpected serious adverse reactions were reported in six HSCTlite patients, including three cases of delayed renal failure due to proven thrombotic microangiopathy. Two HSCTlite patients died. Conclusions Within the limitations of reduced patient recruitment and numbers of patients assessed, HSCTlite meaningfully reduced endoscopic disease activity, with three patients experiencing resolution of ulceration. Suspected unexpected serious adverse reactions, particularly relating to thrombotic microangiopathy, make this regimen unsuitable for future clinical use. Limitations The early trial closure prevented complete recruitment, and the impact of the coronavirus pandemic prevented completion of some study investigations. Small participant numbers meant analysis could only be descriptive. Future work Owing to undetermined aetiology of thrombotic microangiopathy, further trials of HSCTlite in this population are not considered appropriate. Priorities should be to determine optimal treatment strategies for patients with refractory Crohn’s disease, including those with a stoma or multiple previous resections. Trial registration This trial is registered as ISRCTN17160440 and EudraCT 2017-002545-30. Funding This award was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR) partnership. This is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 3. See the NIHR Funding and Awards website for further award information.

A 67-year-old man presented with unilateral weakness and reduced dexterity four months after autolo- gous peripheral blood stem cell transplantation for multiple myeloma. The weakness progressed over the following months, with accompanying cognitive and sensory symptoms. Brain MRI showed numerous hyper- intense T2 lesions within the subcortical white matter of both cerebral hemispheres suggestive of demy- elination, progressing rapidly on interval imaging. His CSF tested positive for JC virus, diagnostic of PML.This diagnosis was unexpected as the patient did not appear to be significantly immunocompromised and PML is extremely rare in patients with multiple myeloma. Treatment for progressive multifocal leukoen- cephalopathy is via restoring immune function; in our patient no reversible cause of immuno-suppression was present. At the time of our patient’s diagnosis no treatments had been shown to be effective against PML in clinical trials. However, in the last year both pembrolizumab and BK virus specific T-cell therapy have demonstrated efficacy against PML in published clinical trials, offering new hope for patients.Clinicians should consider a diagnosis of PML when assessing patients with neurological symptoms and signs following treatment for multiple myeloma and in other haematological conditions, particularly as efficacious treatments can now be given if PML is diagnosed early.peter.fernandes@ed.ac.uk

Myelodysplastic syndrome (MDS) are clonal stem cell diseases characterized mainly by ineffective hematopoiesis. Here, we present an approach that enables robust long-term engraftment of primary MDS stem cells (MDS-SCs) in mice by implantation of human mesenchymal cell-seeded scaffolds. Critically for modelling MDS, where patient sample material is limiting, mononuclear bone marrow cells containing as few as 104 CD34+ cells can be engrafted and expanded by this approach with the maintenance of the genetic make-up seen in the patients. Non-invasive high-resolution ultrasound imaging shows that these scaffolds are fully perfused. Our data shows that human microenvironment but not mouse is essential to MDS-SCs homing and engraftment. Notably, the alternative niche provided by healthy donor MSCs enhanced engraftment of MDS-SCs. This study characterizes a new tool to model MDS human disease with the level of engraftment previously unattainable in mice, and offers insights into human-specific determinants of MDS-SC microenvironment.

PML should be considered in patients with neurological symptoms following MM and in those who are immunosuppressed. Symptoms are diverse and often rapidly progressing. Prompt referral and early involvement of the multidisciplinary team are crucial.

The British Journal of Haematology publishes original research papers in clinical, laboratory and experimental haematology. The Journal also features annotations, reviews, short reports, images in haematology and Letters to the Editor.

Introduction Patients with myeloma are at increased risk of venous thromboembolism (VTE) and arterial thrombosis, particularly when treated with immunomodulatory drugs (IMiDs) such as thalidomide or lenalidomide. The optimal approach to prevent such potentially fatal complications has not been determined. Despite routine thromboprophylaxis with aspirin, low molecular weight heparin (LMWH) or warfarin, thrombosis rates of thrombosis of 2-8% are reported in the literature. Current agents have limited efficacy with significant associated burdens such as repeated INR monitoring or subcutaneous administration. Direct oral anticoagulants are promising due to their convenience and effectiveness in preventing VTE in other settings. They have not been extensively studied in myeloma therapy. Our baseline audit of 82 consecutive myeloma patients treated with IMiD-containing regimens and receiving thromboprohylaxis with aspirin had VTE rates of 11%. Of 31 patients treated with heparins 6.5% had VTE. These rates are consistent with data in the literature. Apixaban is cheaper than LMWH therapy in our centre.In November 2014 our policy was changed such that apixaban became standard thromboprophylaxis; the effect of this change is reported here. Aim Assess the safety and efficacy of apixaban as thromboprophylaxis in patients with multiple myeloma undergoing first line therapy with IMID-containing regimens. Method Consecutively presenting patients between 1st November 2014 and 31st December 2016 with multiple myeloma undergoing first-line therapy with IMiD-containing regimens were included in this retrospective study. All patients received apixaban 2.5mg twice daily for the first 4 months of therapy or until treatment cessation. Patients with severe renal failure (CrCl Results 70patients were identified. 45 (64%) were male, the median age was 66 years, range 43-86. Previous thrombosis: 2 PE, 1 stroke, 1 TIA, 3 myocardial infarction. Treatment (n): Cyclophosphamide-Thalidomide-Dexamethasone (19), Bortezomib-Thalidomide-Dexamethasone (27), Lenalidomide-Dexamethasone (3), Carfilzomib-Cyclophosphamide-Lenalidomide-Dexamethasone (8), Melphalan-Prednisolone-Thalidomide (n=9), Lenalidomide-Cyclophosphamide-Dexamethasone (4). There were no DVTs or PEs within 6 months of treatment initiation. Two patients (2.9%) had arterial thrombosis. One patient had a non-haemorrhagic stroke at day 19 with no identified embolic source and she had no cardiovascular comorbidities. One patient had a non-ST elevation myocardial infarction at day 23 with no previous diagnosis of ischaemic heart disease. He had stopped both thalidomide and apixaban 21 days previously due to drug-induced rash. One patient (1.4%) had major bleeding. He had melaena during his 4th cycle of MPT that resolved on apixaban cessation. His platelet count had dropped to 21x10^9/L during this episode. He required hospital admission for blood transfusion, but no bleeding point was identified at endoscopy. Conclusion - We studied the use of apixaban for preventing IMiD-induced thrombosis in front line myeloma therapy. Rates of thrombosis appear to be very low with no cases of VTE identified and only 2 cases of arterial thrombosis. There was one episode of major bleeding in a patient with coexistent thrombocytopenia. These toxicity rates compare favourably to historical and published data with other anticoagulants. The drug is suitable for ambulatory treatment even in frail patients, and avoids the logistical and acceptability problems of subcutaneous injection of LMWH. Apixaban appears to be an attractive and safe option for thromboprophylaxis in this setting. Disclosures No relevant conflicts of interest to declare.

Plerixafor is a CXC chemokine receptor (CXCR4) antagonist that mobilizes stem cells in the peripheral blood. It is indicated (in combination with granulocyte‐colony stimulating factor [G‐CSF]) to enhance the harvest of adequate quantities of cluster differentiation (CD) 34+ cells for autologous transplantation in patients with lymphoma or multiple myeloma whose cells mobilize poorly. Strategies for use include delayed re‐mobilization after a failed mobilization attempt with G‐CSF, and rescue or pre‐emptive mobilization in patients in whom mobilization with G‐CSF is likely to fail. Pre‐emptive use has the advantage that it avoids the need to re‐schedule the transplant procedure, with its attendant inconvenience, quality‐of‐life issues for the patient and cost of additional admissions to the transplant unit. UK experience from 2 major centers suggests that pre‐emptive plerixafor is associated with an incremental drug cost of less than £2000 when averaged over all patients undergoing peripheral blood stem cell (PBSC) transplant. A CD34+ cell count of <15 µl −1 at the time of recovery after chemomobilization or after four days of G‐CSF treatment, or an apheresis yield of <1 × 10 6 CD34+ cells/kg on the first day of apheresis, could be used to predict the need for pre‐emptive plerixafor.

Abstract Abstract 2039 Introduction. The role of allogeneic stem cell transplantation in the management of aggressive non-Hodgkin's lymphoma (NHL) remains to be established. Autologous stem cell transplantation (SCT) remains the standard salvage therapy for patients with diffuse large B cell lymphoma failing first line therapy although patients relapsing early after Rituximab based immunochemotherapy have a poor outcome. For patients with aggressive T cell lymphomas the role of consolidation or salvage transplant strategies also remains controversial. Reduced intensity allogeneic transplants have been employed in these diseases with variable success. In the United Kingdom the more intensive BEAM conditioning regimen has been employed prior to allogeneic stem cell transplantation in lymphoproliferative diseases. We report here the outcome of BEAM-CAMPATH conditioning prior to allogeneic stem cell transplantation for aggressive NHL as reported to the British Bone Marrow Registry. Methods. We retrospectively identified all patients reported to the BSBMT registry as having undergone an allogeneic stem cell transplant following BEAM-CAMPATH conditioning for aggressive non-Hodgkin's lymphomas. All patients received conditioning with BEAM (BCNU 300mg/m2, etoposide 800mg/m2, cytarabine 1600mg/m2, melphalan 140mg/m2) and CAMPATH-1H 10mg days -6 to -2. Cyclosporin A was administered for 90 days post transplant. Six transplant centres contributed data to this study. Results. 46 patients (27 male, 19 female) with a median age of 45 (range 17–59) at diagnosis with DLBCL (29), Burkitt's lymphoma (1) or T cell lymphoma (PTCL NOS 14, anaplastic large cell lymphoma 3, angioimmunoblastic lymphoma 1) were identified. 37 patients had stage III/IV disease at diagnosis and 56% of patients had a high or high-intermediate International Prognostic Score. They had received a median of 3 lines of prior therapy (range 1–5), 11 of 29 patients with B cell lymphomas had received Rituximab prior to transplant and 4 patients had received a prior autologous stem cell transplant. The median time from diagnosis to transplant was 11 months (range 3 months–13 years) and 22 patients had received the transplant in first response. At transplant 34 patients had chemosenstive disease and 11 patients had chemorefractory disease. Transplants from 32 siblings and 14 volunteer unrelated donors were performed using peripheral blood stem cells in 42 patients. 3 patients received a mismatched transplant. The Performance Status (PS) at transplant was good (KPS>80) in 40 of 46 patients. All patients engrafted with a median time to neutrophil recovery of 14 days (range 11–27). At last follow up 20 patients are alive with 17 in complete remission. 5 patients have died from non-relapse causes (infection 3, GVHD 1, respiratory failure 1) and 21 died following relapse of lymphoma. Acute GVHD grades II-IV developed in 7 patients and chronic GVHD in 13 (7 limited, 6 extensive) of 37 patients surviving beyond 100 days. The cumulative incidence (CI) of non-relapse mortality (NRM) was 7% at 100 days and 11% at 3 and 5 years post transplant. NRM was significantly worse for those with a poor PS, use of a VUD, prior autologous SCT and more lines of prior therapy. The relapse risk at 1 and 5 years was 51% and 53% respectively and was associated with use of a sibling donor. Disease status at transplant had no impact on the relapse rate. The progression free survival (PFS) was 41% and 36% at 1 and 5 years respectively with a trend to a higher PFS in patients under 45 years. The overall survival (OS) was 54% t 1 year and 42% at 5 years with a significantly better OS in CMV low risk transplants. Conclusion. BEAM-CAMPATH conditioning prior to allogeneic SCT is well tolerated in patients with aggressive NHL although there remains a significant relapse rate following this therapy. A significant minority of patients achieve durable disease free survival. The role of BEAM-CAMPATH allogeneic stem cell transplantation in these diseases warrants further investigation. Disclosures: No relevant conflicts of interest to declare.

Background Thalidomide is active in multiple myeloma and is associated with minimal myelosuppression, making it a good candidate for induction therapy prior to high-dose therapy with autologous stem-cell transplantation.Design and Methods Oral cyclophosphamide, thalidomide, and dexamethasone was compared with infusional cyclophosphamide, vincristine, doxorubicin, and dexamethasone in patients with newly diagnosed multiple myeloma.Results The post-induction overall response rate (≥ partial response) for the intent-to-treat population was significantly higher with cyclophosphamide-thalidomide-dexamethasone (n=555) versus cyclophosphamide-vincristine-doxorubicin-dexamethasone (n=556); 82.5% versus 71.2%; odds ratio 1.91; 95% confidence interval 1.44–2.55; P

Abstract Abstract 3105 Background: EATL is a rare subtype of peripheral T-cell lymphomas characterized by primarily intestinal localization and a frequent association with celiac disease. The prognosis is considered to be poor with conventional chemotherapy. Limited data is available on the efficacy of ASCT in this lymphoma subtype. Primary objective was to study the outcome of ASCT as a consolidation or salvage strategy for EATL. The primary endpoint was overall survival (OS) and progression-free survival (PFS). Eligible patients were > 18 years who had received ASCT between 2000–2010 for EATL that was confirmed by review of written histopathology reports, and had sufficient information on disease history and follow-up available. The search strategy used the EBMT database to identify patients potentially fulfilling the eligibility criteria. An additional questionnaire was sent to individual transplant centres to confirm histological diagnosis (histopathology report or pathology review) as well as updated follow-up data. Patients and transplant characteristics were compared between groups using X2 test or Fisher's exact test for categorical variables and t-test or Mann-Whiney U-test for continuous variables. OS and PFS were estimated using the Kaplan-Meier product-limit estimate and compared by the log-rank test. Estimates for non-relapse mortality (NRM) and relapse or progression were calculated using cumulative incidence rates to accommodate competing risk and compared to Gray's test. Results: Altogether 138 patients were identified. Updated follow-up data was received from 74 patients (54 %) and histology report from 54 patients (39 %). In ten patients the diagnosis of EATL could not be adequately verified. Thus the final analysis included 44. There were 24 males and 20 females with a median age of 56 (35–72) years at the time of transplant. Twenty-five patients (57 %) had a history of celiac disease. Disease stage was I in nine patients (21 %), II in 14 patients (33 %) and IV in 19 patients (45 %). Twenty-four patients (55 %) were in the first CR or PR at the time of transplant. BEAM was used as a high-dose regimen in 36 patients (82 %) and all patients received peripheral blood grafts. The median follow-up for survivors was 46 (2–108) months from ASCT. Three patients died early from transplant-related reasons translating into a 2-year non-relapse mortality of 7 %. Relapse incidence at 4 years after ASCT was 39 %, with no events occurring beyond 2.5 years after ASCT. PFS and OS were 54 % and 59 % at four years, respectively. There was a trend for better OS in patients transplanted in the first CR or PR compared to more advanced disease status (70 % vs. 43 %, p=0.053). Of note, patients with a history of celiac disease had superior PFS (70 % vs. 35 %, p=0.02) and OS (70 % vs. 45 %, p=0.052) whilst age, gender, disease stage, B-symptoms at diagnosis or high-dose regimen were not associated with OS or PFS. Conclusions: This study shows for the first time in a larger patient sample that ASCT is feasible in selected patients with EATL and can yield durable disease control in a significant proportion of the patients. Patients transplanted in first CR or PR appear to do better than those transplanted later. ASCT should be considered in EATL patients responding to initial therapy. Disclosures: No relevant conflicts of interest to declare.

In vivo alemtuzumab reduces the risk of graft-versus-host disease (GVHD) and nonrelapse mortality after reduced intensity allogeneic transplantation. However, it also delays immune reconstitution, leading to frequent infections and potential loss of graft-versus-tumor responses. Here, we tested the feasibility of alemtuzumab dose deescalation in the context of fludarabine-melphalan conditioning and human leukocyte antigen (HLA)-identical sibling transplantation. Alemtuzumab was given 1-2 days before graft infusion, and dose reduced from 60 mg to 20 mg in 4 sequential cohorts (total n = 106). Pharmacokinetic studies were fitted to a linear, 2-compartment model in which dose reduction led to incomplete saturation of CD52 binding sites and greater antibody clearance. Increased elimination was particularly evident in the 20-mg group in patients who had CD52-expressing tumors at time of transplantation. The 20-mg dose was also associated with greater risk of severe GVHD (acute grade III-IV or chronic extensive) compared with > 20 mg (hazard ratio, 6.7; 95% CI, 2.5-18.3). In contrast, dose reduction to 30 mg on day -1 was associated with equivalent clinical outcomes to higher doses but better lymphocyte recovery at 12 months. In conclusion, alemtuzumab dose reduction to 30 mg is safe in the context of reduced intensity conditioning and HLA-identical sibling transplantation. This trial was registered at http://www.ncrn.org.uk as UKCRN study 1415.

Familial platelet disorder with propensity to myeloid malignancy (FPD/AML) is an autosomal dominant syndrome characterized by platelet abnormalities and a predisposition to myelodysplasia (MDS) and/or acute myeloid leukemia (AML). The disorder, caused by inherited mutations in RUNX1, is uncommon with only 14 pedigrees reported. We screened 10 families with a history of more than one first degree relative with MDS/AML for inherited mutations in RUNX1. Germ- line RUNX1 mutations were identified in 5 pedigrees with a 3:2 predominance of N-terminal mutations. Several affected members had normal platelet counts or platelet function, features not previously reported in FPD/AML. The median incidence of MDS/AML among carriers of RUNX1 mutation was 35%. Individual treatments varied but included hematopoietic stem cell transplantation from siblings before recognition of the inherited leukemogenic mutation. Transplantation was associated with a high incidence of complications including early relapse, failure of engraftment, and posttransplantation lymphoproliferative disorder. Given the small size of modern families and the clinical heterogeneity of this syndrome, the diagnosis of FPD/AML could be easily overlooked and may be more prevalent than previously recognized. Therefore, it would appear prudent to screen young patients with MDS/AML for RUNX1 mutation, before consideration of sibling hematopoietic stem cell transplantation.

Dendritic cell (DC) vaccines in leukaemia show promise as a novel treatment modality aimed at reducing relapse rates by augmenting immune responses when patients are in a state of minimal residual disease. DC vaccination studies to date have not been as successful as hoped and this may be because of insufficient cytotoxic T cell (CTL) responses. Immunomodulatory agents such as 4-IBB ligand, and cytokines such as IL2, IL6 and GM-CSF have been reported to improve vaccine therapy however these agents have to be tolerated clinically and this limits the use of some preparations. Our study aims to generate a more efficient DC vaccine process by using Lenalidomide, a thalidomide analogue and immunomodulatory agent which is a powerful potentiator of CTLs and natural killer cells. It has the advantage of clinical tolerability and is already in use for treating haematological malignancies. In this in vitro study DCs were generated from monocytes of eight patients in remission following chemotherapy for acute myeloid leukaemia (AML) or chronic myeloid leukaemia (CML) with standard cytokine protocols. The immature DCs were loaded with autologous leukaemia cells from the patients’ presentation samples. The presentation leukaemia cells were treated with UVB irradiation to induce apoptosis. DCs were matured with TNF alpha for two days then co-cultured with autologous T cells for one week with or without the addition of Lenalidomide at ten micromolar. A control group of unstimulated T cells were kept in culture for the same time period. The T cells from the three groups were harvested and their cytoxicity assessed in an Interferon Gamma (IFNγ) ELISPOT assay where the stimulators used were the unmodified blasts. Results in all eight patients show the leukaemia specific CTL responses (as measured by IFNγ release) were markedly improved in the DC/irradiated blasts groups compared with the unstimulated T cells. In six out of eight patients there was a further, significant improvement in the groups where Lenalidomide was added (see Figure 1). ![Figure][1] Figure These results show promise for the use Lenalidomide as an agent to optimise CTL responses to DC based Immunotherapy for myeloid leukaemia and should be investigated further in a clinical trial. [1]: pending:yes

Dendritic cell (DC) vaccines in leukemia show promise as a novel treatment modality however to date clinical evidence of efficacy has been limited. This is likely to be as a consequence of a combination of factors, which include insufficient immunogenicity of the DC vaccine and vaccination taking place in an environment adverse for generation of effective immune responses i.e. in patients with active disease. Our study aims to generate more efficient cytotoxic T cell (CTL) responses by improving DC uptake and presentation of leukemia cells in the remission state and will be applicable to both acute and chronic leukemias. Monoclonal antibodies (MoAbs) have been used to treat malignant cells prior to co-culture with DCs to enhance cross-presentation and generation of specific CTLs. We investigated whether this approach could improve DC induction of CTL responses in comparison to DCs loaded with UVB irradiated apoptotic leukemia cells. In this in vitro study we generated dendritic cells from adherent mononuclear cells (differentiation with GM-CSF and IL-4) of patients in remission following chemotherapy for acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL). The immature DCs were loaded with autologous leukemia cells from the patients' presentation samples. The presentation leukemia cells were treated with either UVB irradiation or appropriate monoclonal antibodies (the anti-CD33 MoAb Mylotarg in AML and CML; the anti CD20 MoAb Rituximab or the anti-CD 52 MoAb Alemtuzumab in CLL). Apoptosis was assessed by Annexin/Propidium iodide labelling. Treatment of the leukemia cells by different MoAbs induced varying degrees of apoptosis. DC uptake of antibody treated or apoptotic leukemia cells was assessed by dual colour staining. Leukemia cells were stained with PKH and DCs labelled with FITC-CD80 or CD86. DC uptake was more efficient with MoAb treated cells irrespective of the degree of apoptosis induced by the MoAb. DCs were matured with TNFa for two days then co-cultured with autologous T cells for one week. T cell subsets and Regulatory T cells were assessed on the presentation and remission samples.The T cells were harvested and their cytoxicity assessed in an Interferon Gamma (IFNg) ELISPOT assay where the unmodified blasts were used as stimulators. Initial results show enhanced anti-leukemia activity in the MoAb treated group as compared to the irradiated group. A similar set up using allogeneic DCs and T cells confirmed the augmentation of CTL responses with MoAb treatment of leukemia cells.The use of MoAb in this setting shows promise for improvement in the success and applicability of DC vaccine strategies in leukemia.