scholarly journals Dendritic Cells Stimulate the Expansion of bcr-abl Specific CD8+ T Cells With Cytotoxic Activity Against Leukemic Cells From Patients With Chronic Myeloid Leukemia

Blood ◽  
1998 ◽  
Vol 91 (3) ◽  
pp. 977-983 ◽  
Author(s):  
Mie Nieda ◽  
Andrew Nicol ◽  
Akiko Kikuchi ◽  
Koichi Kashiwase ◽  
Kerry Taylor ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Chronic Myeloid Leukemia ◽  
Cytotoxic Activity ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Class I ◽  
Leukemic Cells ◽  
Normal Donor

Abstract The role of T lymphocytes in the control of chronic myeloid leukemia (CML) after bone marrow transplantations has been clearly shown. This effect closely correlates with graft-versus-host disease (GVHD). A specific graft-versus-leukemia (GVL) effect separate from GVHD has been postulated but has been difficult to show. One possible target for specific GVL activity is the bcr-abl fusion protein characteristic of CML. We have investigated the use of normal peptide-pulsed dendritic cells for the generation of cytotoxic, bcr-abl–specific T cells from normal donors. T cells (CD3+, CD8+, TCRαβ+, and NK receptor-negative) generated from a normal donor (HLA A24, B52, B59, Cw1) after stimulation with autologous dendritic cells, primed with a 16 mer peptide spanning the b3a2 breakpoint of bcr-abl, lysed CML cells from the peripheral blood of seven patients with CML with the b3a2 breakpoint. CML cells from four patients with only the b2a2 breakpoint were not lysed. Phytohemagglutinin (PHA) blasts derived from peripheral blood of patients with CML were not lysed, suggesting that cytotoxicity was not due to alloreactivity. Blocking experiments with anti–HLA-A,B,C indicated that cytotoxicity was dependent on recognition of major histocompatibility complex (MHC) class I molecules, although cytotoxicity was not MHC-restricted because not all patients shared HLA types with the T-cell donor. Specificity for bcr-abl and absence of alloreactivity was confirmed by the presence of lytic activity against autologous and allogeneic class I HLA-A matched monocytes pulsed with the 16 mer bcr-abl fusion peptide, but not against unpulsed monocytes or monocytes pulsed with other peptides. These results show that bcr-abl–specific T cells with marked cytotoxic activity against CML cells can be generated and amplified from normal donor peripheral blood. Recognition of HLA molecules is essential for cytotoxicity but strict HLA identity is not required.

scholarly journals Dendritic Cells Stimulate the Expansion of bcr-abl Specific CD8+ T Cells With Cytotoxic Activity Against Leukemic Cells From Patients With Chronic Myeloid Leukemia

Blood ◽  
1998 ◽  
Vol 91 (3) ◽  
pp. 977-983 ◽  
Author(s):  
Mie Nieda ◽  
Andrew Nicol ◽  
Akiko Kikuchi ◽  
Koichi Kashiwase ◽  
Kerry Taylor ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Chronic Myeloid Leukemia ◽  
Cytotoxic Activity ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Class I ◽  
Leukemic Cells ◽  
Normal Donor

The role of T lymphocytes in the control of chronic myeloid leukemia (CML) after bone marrow transplantations has been clearly shown. This effect closely correlates with graft-versus-host disease (GVHD). A specific graft-versus-leukemia (GVL) effect separate from GVHD has been postulated but has been difficult to show. One possible target for specific GVL activity is the bcr-abl fusion protein characteristic of CML. We have investigated the use of normal peptide-pulsed dendritic cells for the generation of cytotoxic, bcr-abl–specific T cells from normal donors. T cells (CD3+, CD8+, TCRαβ+, and NK receptor-negative) generated from a normal donor (HLA A24, B52, B59, Cw1) after stimulation with autologous dendritic cells, primed with a 16 mer peptide spanning the b3a2 breakpoint of bcr-abl, lysed CML cells from the peripheral blood of seven patients with CML with the b3a2 breakpoint. CML cells from four patients with only the b2a2 breakpoint were not lysed. Phytohemagglutinin (PHA) blasts derived from peripheral blood of patients with CML were not lysed, suggesting that cytotoxicity was not due to alloreactivity. Blocking experiments with anti–HLA-A,B,C indicated that cytotoxicity was dependent on recognition of major histocompatibility complex (MHC) class I molecules, although cytotoxicity was not MHC-restricted because not all patients shared HLA types with the T-cell donor. Specificity for bcr-abl and absence of alloreactivity was confirmed by the presence of lytic activity against autologous and allogeneic class I HLA-A matched monocytes pulsed with the 16 mer bcr-abl fusion peptide, but not against unpulsed monocytes or monocytes pulsed with other peptides. These results show that bcr-abl–specific T cells with marked cytotoxic activity against CML cells can be generated and amplified from normal donor peripheral blood. Recognition of HLA molecules is essential for cytotoxicity but strict HLA identity is not required.

The Role of Human T-Lymphotropic Virus Type 1 (HTLV-1)-Infected Dendritic Cells in the Development of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis

1999 ◽  
Vol 73 (6) ◽  
pp. 4575-4581 ◽  
Author(s):  
Masahiko Makino ◽  
Satoshi Shimokubo ◽  
Shin-Ichi Wakamatsu ◽  
Shuji Izumo ◽  
Masanori Baba
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Virus Type ◽  
Spastic Paraparesis ◽  
Tropical Spastic Paraparesis ◽  
Normal Donor ◽  
Dependent Manner ◽  
T Lymphotropic Virus

ABSTRACT The development of human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is closely associated with the activation of T cells which are HTLV-1 specific but may cross-react with neural antigens (Ags). Immature dendritic cells (DCs), differentiated from normal donor monocytes by using recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin-4, were pulsed with HTLV-1 in vitro. The pulsed DCs contained HTLV-1 proviral DNA and expressed HTLV-1 Gag Ag on their surface 6 days after infection. The DCs matured by lipopolysaccharides stimulated autologous CD4+ T cells and CD8+ T cells in a viral dose-dependent manner. However, the proliferation level of CD4+ T cells was five- to sixfold higher than that of CD8+ T cells. In contrast to virus-infected DCs, DCs pulsed with heat-inactivated virions activated only CD4+ T cells. To clarify the role of DCs in HAM/TSP development, monocytes from patients were cultured for 4 days in the presence of the cytokines. The expression of CD86 Ag on DCs was higher and that of CD1a Ag was more down-regulated than in DCs generated from normal monocytes. DCs from two of five patients expressed HTLV-1 Gag Ag. Furthermore, both CD4+ and CD8+ T cells from the patients were greatly stimulated by contact with autologous DCs pulsed with inactivated viral Ag as well as HTLV-1-infected DCs. These results suggest that DCs are susceptible to HTLV-1 infection and that their cognate interaction with T cells may contribute to the development of HAM/TSP.

Plasma RNA Is More Reliable Than Peripheral Blood Cells for Monitoring Molecular Response to Imatinib in Patients with Chronic Myeloid Leukemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2007-2007
Author(s):  
W. Ma ◽  
R. Tseng ◽  
M. Gorre ◽  
I. Jilani ◽  
M. Keating ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
The Body ◽  
Leukemic Cells ◽  
Molecular Response ◽  
Plasma Samples ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Reliable Source

Abstract With the use of imatinib for treatment of chronic myeloid leukemia (CML), monitoring treatment response and quantifying leukemic cells in the body by specific detection of the bcr-abl fusion gene or its mRNA is becoming the standard of care. The high frequency of complete cytogenetic response in CML patients has led to reliance on quantitative reverse-transcription-polymerase chain reaction (qRT-PCR) for detection of the bcr-abl mRNA when monitoring therapy. Peripheral blood (PB) and bone marrow (BM) specimens are usually used for qRT-PCR assays. However, standardization of the qRT-PCR assay and issues regarding sampling and the number of cells that need to be analyzed make reliance on such assays problematic. We previously showed that leukemic cells pour their RNA, DNA, and protein into circulation and, because of their high turnover rate, enrich the plasma with these components. We also hypothesize that plasma mRNA reflects disease activity in the entire body rather than the few cells in the analyzed sample, making plasma a more reliable source than PB cells. In this study we compared qRT-PCR results obtained from PB cells with those obtained from plasma in CML patients being treated with imatinib. PB cell and plasma samples obtained at baseline (n=67) and at 3 (n=43), 6 (n=22), 9 (n=19), and 12 (n=9) months of therapy were compared. The same qRT-PCR assay was used for cell- and plasma-based testing. However, the RNA extraction from plasma was standardized by using equal amounts from all samples and the RNA from 50μL plasma for each qRT-PCR assay. All plasma samples from CML patients were positive at baseline, whereas testing of more than 180 plasma samples from normal individuals or patients with leukemia other than CML showed no detectable bcr-abl transcript. In CML patients, the pattern of changes with therapy in the qRT-PCR in the plasma paralleled that obtained from cell-based testing. At 3 months, all patients who were negative by plasma-based testing were also negative by cell-based testing, whereas 6 of the 14 negative patients by cell-based testing were positive by plasma-based testing. At 6 months of therapy, 8 patients were negative by cell-based testing and all but 1 of these were negative by plasma; this patient was positive by plasma-based testing and became positive by cell-based testing at 9 and 12 months. 10 patients were negative by plasma-based testing at 6 months, 3 of whom were positive by cell-based testing. However, 2 of these 3 became negative by cell-based testing at 9 months and remained negative at 12 months. At 9 months of therapy, 9 patients were negative by cell-based testing, of whom 3 were positive by plasma-based testing; these 3 became positive by cell-based testing at 12 months. 8 patients were negative by plasma-based testing at 9 months, 1 of whom was positive by cell-based qRT-PCR. However, this patient became negative by cell-based testing at 12 months. This data show not only that plasma is a reliable source for testing and monitoring patients with CML, but that it is more reliable than PB cells for monitoring molecular response in CML. Furthermore, because plasma-based test results can be reported as mRNA copies/μL plasma, this platform has the potential to allow better standardization of testing among laboratories.

DC-Based Vaccines Show in-Vitro Activity against Chronic Myeloid Leukemia Cells

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4276-4276
Author(s):  
Yuen-Fen Tan ◽  
Soon-Keng Cheong ◽  
Chooi-Fun Leong ◽  
SAW Fadhilah
Keyword(s):  
T Cells ◽  
Immune System ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Residual Disease ◽  
Leukemic Cells ◽  
Gm Csf ◽  
Dc Vaccine ◽  
Hla Dr

Abstract Chronic Myeloid leukemia is a common myeloproliferative disease. Despite recent advances in targeted therapy, only 7–12% of patients achieve molecular remission. Leukemic cells arrange multiple mechanisms to avoid recognition by the immune system. Dendritic cells (DC) are professional antigen presenting cells of the immune system playing a crucial role in the induction of anti-tumor responses. The use of DC is an attractive immunotherapeutic strategy against cancers, especially in minimal residual disease state. In this study, DC vaccine against chronic myeloid leukemia was generated and evaluated in-vitro. Monocytes were isolated and enriched from peripheral blood. These monocytes were subsequently cultured in RPMI medium supplemented with GM-CSF and IL-4 to induce them to become DC. These DC were then co-cultured with tumor lysates obtained from CML cell line in culture medium supplemented with GM-CSF, IL-4 and TNF alpha to become DC-based CML vaccine. The generated DC-based CML vaccines retained their DC morphology, showed strong expression of CD 86 and HLA-DR, and were negative for CD14. Mixed lymphocyte reaction indicated that the generated DC-based CML vaccines were capable of inducing proliferative responses to allogeneic lymphocytes. DC-based CML vaccines were shown to stimulate T cells to express DC-ligands, ie CD28 and CD154, as well as HLA-DR, CD71 and CD 25. In addition, the stimulated T cells were cytotoxic to CML cells used to prepare tumor lysates.

scholarly journals Leukemic burden in subpopulations of CD34+ cells isolated from the mobilized peripheral blood of alpha-interferon-resistant or -intolerant patients with chronic myeloid leukemia

Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4348-4357 ◽  
Author(s):  
D Van den Berg ◽  
M Wessman ◽  
L Murray ◽  
J Tong ◽  
B Chen ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Alpha Interferon ◽  
Leukemic Cells ◽  
Cell Subpopulation ◽  
Fish Analysis ◽  
Cd34 Cells ◽  
The Mean ◽  
Mobilized Peripheral Blood

We attempted to determine the frequency of normal hematopoietic stem cells (HSC) and contaminating leukemic cells in mobilized peripheral blood (MPB) collected from chronic myeloid leukemia (CML) patients, intolerant of alpha-interferon or with interferon-resistant disease. A total of 14 MPB samples, six from patients in chronic phase (CP) and eight from patients in accelerated phase or blast crisis (AP/BC) were studied. Cytogenetic analysis of MPB collected from AP/BC patients showed that 100% of the cells were Ph+, whereas cells from four of five CP MPB were Ph-. By contrast, fluorescence in situ hybridization (FISH) analysis of CP MPB showed a mean frequency of 14.7% Ph+ cells, while AP/BC MPB contained 39.2% Ph+ cells. In an attempt to purify normal HSC, subpopulations of the MPB CD34+ cells were isolated based on expression of the Thy-1 antigen (CDw90). The mean Ph+ cell frequency as determined by FISH within the CD34+Thy-1+Lin- and CD34+Thy-1-Lin- populations from CP patients was 19.2% and 33.9%, respectively. In the AP/BC patients, levels of residual leukemic cells were significantly greater with mean Ph+ cell frequencies of 59.2% and 72.7% for the CD34+Thy-1+Lin- and CD34+Thy-1-Lin- fractions, respectively. The frequency of cobblestone area forming cells (CAFC) was used as a means of quantitating the numbers of functional HSC within these cell subpopulations. The mean CAFC frequency was 1 of 19 for the CD34+Thy- 1+Lin- cells as compared with 1 of 133 for the Thy-1-fraction indicating a higher frequency of primitive progenitor cells in the Thy- 1+ subpopulation. CD34+ cell subsets from two patients were also injected into SCID-hu bone assays to determine the in vivo behavior of these cell populations. After 8 weeks, multilineage donor engraftment was observed in these grafts. FISH analysis of the donor cells within the grafts showed that 55.3% and 60.0% of the cells were Ph+. We conclude that unfractionated MPB from this patient population is not leukemia-free and that the CD34+Thy-1+Lin- cell subpopulation, although predominantly enriched for normal HSC, still contains substantial numbers of residual leukemic cells.

scholarly journals HLA-G Expression on Blasts and Tolerogenic Cells in Patients Affected by Acute Myeloid Leukemia

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Grazia Locafaro ◽  
Giada Amodio ◽  
Daniela Tomasoni ◽  
Cristina Tresoldi ◽  
Fabio Ciceri ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Immune Escape ◽  
Human Leukocyte ◽  
Treg Cells ◽  
Leukemic Cells ◽  
Tolerogenic Dendritic Cells ◽  
Acute Myeloid

Human Leukocyte Antigen-G (HLA-G) contributes to cancer cell immune escape from host antitumor responses. The clinical relevance of HLA-G in several malignancies has been reported. However, the role of HLA-G expression and functions in Acute Myeloid Leukemia (AML) is still controversial. Our group identified a subset of tolerogenic dendritic cells, DC-10 that express HLA-G and secrete IL-10. DC-10 are present in the peripheral blood and are essential in promoting and maintaining tolerance via the induction of adaptive T regulatory (Treg) cells. We investigated HLA-G expression on blasts and the presence of HLA-G-expressing DC-10 and CD4+T cells in the peripheral blood of AML patients at diagnosis. Moreover, we explored the possible influence of the 3′ untranslated region (3′UTR) ofHLA-G, which has been associated with HLA-G expression, on AML susceptibility. Results showed that HLA-G-expressing DC-10 and CD4+T cells are highly represented in AML patients with HLA-G positive blasts. None of the HLA-G variation sites evaluated was associated with AML susceptibility. This is the first report describing HLA-G-expressing DC-10 and CD4+T cells in AML patients, suggesting that they may represent a strategy by which leukemic cells escape the host’s immune system. Further studies on larger populations are required to verify our findings.

Dendritic Cells Vaccination in BCR/ABL-Positive Chronic Myeloid Leukemia - Final Results of a Phase I/II Study.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2934-2934
Author(s):  
Jörg Westermann ◽  
Joachim Kopp ◽  
Antje van Lessen ◽  
Ann Hecker ◽  
Gökben Baskaynak ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Myeloid Leukemia ◽  
Quantitative Pcr ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Fish Analysis ◽  
Severe Toxicity ◽  
Post Vaccination ◽  
Final Maturation ◽  
Vaccination Period

Abstract T cells recognizing truly leukemia-specific antigens like bcr/abl or other leukemia-associated antigens such as proteinase3 and WT1 have been demonstrated by several groups. In chronic myeloid leukemia (CML), DC and leukemic cells share a common progeny, leading to constitutive expression of putative tumor antigens such as bcr/abl in DC. Aim of our clinical GMP study was the use of autologous DC as a vaccine in patients with chronic phase bcr/abl+ CML, who had not achieved a major cytogenetic response after treatment with imatinib or a-interferon. Primary endpoint of the study were feasibility and toxicity of DC vaccination, secondary endpoints were reduction of bcr/abl+ mononuclear cells in peripheral blood (measured by FISH and quantitative PCR) and induction of an immune response against leukemia-associated antigens. 10 patients were enrolled, 9 patients did receive the vaccine. DC were generated by leukapheresis from peripheral blood monocytes. DC were cultured in RPMI 1640 supplemented with clinical grade FCS in the presence of GM-CSF (100 ng/ml) and IL-4 (1000U/ml). Final maturation was achieved by addition of TNF-a (50 ng/ml) for 3 days. Flowcytometric analysis on day 8/9 of the cell culture showed that DC had a mature phenotype with strong expression of CD80, CD86, CD83 and HLA-DR. In all patients sufficient numbers of functional DC could be generated. By FISH analysis it could be demonstrated that the mean value of bcr/abl-positive cells in the DC cultures was 33% (range: 3–70%). DC were pulsed with KLH for 3–4 hours prior to clinical use. Vaccination was performed by subcutaneous injection in the inguinal region on days 1, 2, 8 and 21 using increasing numbers of DC per injection (1 to 50 x 10e6 cells per injection). 36 vaccinations were performed in nine patients. The follow-up period was three months. There was no severe toxicity, all vaccinated patients developed a strong DTH reaction, mostly after the third vaccination. In 5/9 patients bcr/abl+ PBMC decreased over the vaccination period, in 2/4 patients quantitative PCR also showed a decrease of bcr/abl in peripheral blood. Only in one of these patients this decrease could clearly be attributed to changes in concomitant therapy during the post-vaccination period. In two patients low frequency T cells recognizing the bcr/abl fusion region were detected by ELISpot or tetramer staining. In all patients PBMC showed an increase in the proliferative response against autologous DC over the post-vaccination period, this increase was partially due to immunization against FCS. We conclude that vaccination of CML patients after large scale GMP generation of bcr/abl+ DC is feasible and safe. Leukemic DC are able to induce T cell activation. A decrease in tumor cell burden/circulating bcr/abl+ cells in some patients suggests that vaccination with DC might possibly be useful as post remission therapy in CML patients after imatinib.

Expansion of Inhibitory NK Receptor (CD94/NKG2A)-Expressing CD8 T Cells from Various Blood Mononuclear Cells with Cytolytic Activity Against Primary Leukemic Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4967-4967
Author(s):  
Junji Tanaka ◽  
Noriaki Iwao ◽  
Tomomi Toubai ◽  
Yoko Miura ◽  
Naoko Kato ◽  
...  
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Hla Class I ◽  
Cytolytic Activity ◽  
Class I ◽  
Leukemic Cells ◽  
Normal Donor ◽  
Hla Class I Molecules ◽  
Different Sources

Abstract Leukemic cells and tumor cells can be escaped from allogeneic recognition by usual cytotoxic T cells because of the low expression level of HLA class I molecules. It has recently been shown that inhibitory natural killer cell receptors (NKRs) on not only NK cells but also on T cells negatively regulate NK cell and T cell functions through their binding to MHC class I molecules. The C-type lectin superfamily inhibitory NKR (CD94/NKG2A) heterodimer recognizes an HLA-E that preferably bound to a peptide derived from the signal sequences of most HLA class I. Therefore, CD94 can monitor the global status of HLA class I on the tumor and leukemic cells and induce cytolytic attack without inhibitory signal against HLA class I decreased target cells. In this study, we expanded CD94-expressing T cells from four different sources of blood mononuclear cells (BMCs) and then investigated their cytolytic characteristics against patients’ primary leukemic cells in order to develop a potential strategy of cell therapy for hematological malignancy. We could get more than 100 fold expansion of CD94-expressing CD8 T cells from normal donor PBMC, apheresed PBMC without G-CSF mobilization from normal donor, apheresed PBMC with G-CSF mobilization from patients after chemotherapy and cord blood after 7 days culture with immobilized anti-CD3 monoclonal antibody (1μg/mL) and IL-15 (5 ng/mL). Cytolytic activities of purified CD94-expressing cells using magnetic cell sorting (MACS) (CD94 > 90%) detected by 4 hours 51 Cr release assay against HLA class I intermediate primary leukemic cells (AML M0, M2, M4, CML CP, BC, MDS overt) (50 < mean fluorescence intensity (MFI) < 150) were 35.6 ± 12.8 % (n=21). However, CTL activities against HLA class I high primary leukemic cells (ATL, ALL, LBL)(MFI>150) were lower than 10 % (6.5 ± 4.2, n=5). Also, CTL activities against HLA class I very high PHA autoblasts and alloblasts (MFI>200) were lower than 5 % (4.0 ± 3.6, n=11). Although the cytolytic activity of CD94-expressing cells roughly depends on the expression of HLA class I molecules in inverse proportion, adhesion molecules and also activating molecules such as NKG2D on effector cells might be important for the regulation of the killing activity. In fact, anti-NKG2D mAb (50 μg/mL) suppressed the cytolytic activity of CD94-expressing cells against patients’ primary leukemic cells (% reduction of cytolytic activity, 22.5± 5.9, n=13). Furthermore, anti-LFA-1 mAb (20 μg/mL) suppressed the cytolytic activity of CD94-expressing cells much more effectively than did anti-NKG2D mAb(% reduction of cytolytic activity, 74.2±15.5, n=13, p<0.01). Our data indicated that the cytolytic activity of inhibitory NKR-expressing cells depends at least partially on NKG2D-activating NKR and also required adhesion through LFA-1. In this study, we were able to expand CD94-expressing CD8 T cells which have both inhibitory receptors (NKG2A) and stimulatoy receptors (NKG2D) as well as LFA-1 and ICAM-1 from four different sources of BMCs. Therefore, it may be possible to expand CD94-expressing cells from various sources of BMCs with cytolytic activity against both autologous and allogeneic primary leukemic cells for a new strategy of cell therapy.

Vaccination of Acute Myeloid Leukemia Patients with Dendritic Cells Electroporated with mRNA Encoding the Wilms’ Tumor Protein WT1: A Phase I/II Trial.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 158-158 ◽  
Author(s):  
Zwi N. Berneman ◽  
Ann Van Driessche ◽  
Ann Van de Velde ◽  
Griet Nijs ◽  
Tessa Braeckman ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Wilms Tumor ◽  
Rna Expression ◽  
Acute Myeloid

Abstract To date, Wilms’ tumor protein (WT1) is acknowledged as a valuable target for active specific immunotherapy in several solid and hematological malignancies, such as leukemia. Preclinical data from our laboratory and that of Hans Stauss have already shown that WT1 RNA-electroporated dendritic cells (DC) stimulate WT1-specific T cells in vitro (Van Driessche A et al. Leukemia2005;19:1863–1871). Therefore, we started a phase I/II dose-escalation trial in which patients with acute myeloid leukemia (AML) in remission received intradermal injections with WT1 RNA-loaded DC. Feasibility, safety and immunogenicity of the vaccine were investigated. Seven patients received four biweekly DC vaccines. A delayed-type hypersensitivity (DTH) test was performed 2 weeks following the last vaccination. Patients underwent an apheresis and monocytes were isolated using CD14-labeled magnetic beads by CliniMACS. DC were generated in 6-day cultures in clinical-grade medium supplemented with serum, GM-CSF and IL-4 and maturated with PGE2 and TNF-a. Keyhole limpet hemocyanin (KLH) was added during maturation as a CD4+ helper antigen. Mature DC were harvested, electroporated with WT1 mRNA and used as vaccines. Patients were monitored for minimal residual disease (MRD) by analyzing WT1 RNA expression in peripheral blood by qRT-PCR. When the patient was HLA-A2+, tetramer staining was performed to detect WT1-specific CD8+ T cells. Before and after the vaccination cycle, peripheral blood was collected for immunomonitoring purposes. There was successful DC generation and vaccine production in all patients selected. No serious adverse events or toxicity was seen and all vaccinations were well tolerated. A decrease in WT1 RNA expression was observed during the course of the vaccination in 3/5 patients who had an increased WT1 mRNA level in peripheral blood at the start of DC vaccination. A vaccine-specific immune response was demonstrated in 7/7 patients by an in vivo DTH reaction both to KLH as well as to WT1. By tetramer analysis, detectable levels of WT1-specific CD8+ T cells could be demonstrated during the course of the vaccination both in the peripheral blood as well as in the expanded DTH-infiltrating T cells from the skin biopsies. Preliminary data from immunomonitoring in pre- and post-vaccination T cell samples from 3 patients show a mixed T helper (Th)1/Th2 response towards the KLH and the WT1 protein following vaccination. We conclude that vaccination of AML remission patients with WT1 RNA-loaded DC is feasible and safe. Furthermore, the vaccine elicits anti-vaccine T-cell responses in vivo and a decrease in WT1 RNA expression levels was observed during MRD monitoring in some vaccinated patients.

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