12th Congress of the European Hematology ... - Haematologica

12 th Congress of the European Hematology Association
0186
PROGNOSIS AFTER UNMANIPULATED HLA HAPLOIDENTICAL BLOOD AND MARROW
TRANSPLANTATION IS CORRELATED TO THE NUMBERS OF KIR LIGANDS IN RECIPIENTS
X.-J. Huang, X.-Y. Zhao, K.-Y. Liu, L.-P. Xu, D.-H. Liu
Peking University Institute of Hematology, BEIJING, China
Background and Aims. The goal of this study was to explore the role of
NK cell alloreaction in predicting prognosis under unmanipulated HLAhaploidentical
blood and marrow transplantation and examine whether
the presence of any individual donor-activating KIR gene had an influence
on the clinical outcome. Methods. We studied the HLA and KIR
genotype of 64 donor-recipient pairs, who underwent transplantation.
Results. In contrast to Perugia’s KIR ligand-ligand mismatch model or
Handgretinger’s KIR receptor-ligand mismatch model or Bignon’s KIR
gene-gene mismatch model between donor-recipient pairs, we found
that the cumulative incidence of 3-year disease-free survival (DFS), overall
survival (OS), and transplantation-related mortality (TRM) were best
predicted by the number of KIR ligands carried by patients (HR 0.355,
95%CI, 0.186-0.678, p=0.002 for DFS; HR 0.445, 95%CI, 0.233-0.848,
p=0.014 for OS; HR 0.450, 95%CI, 0.219-0.926, p=0.030 for TRM).
Moreover, an analysis of KIR ligand numbers was found to be correlative
in patients with lymphoid malignancy. The KIR ligand-ligand mismatch
model is a good predictor of acute graft versus host disease
(aGVHD, HR 3.812, 95%CI, 1.667-8.720, p=0.002). Meanwhile, the
presence of donor-activating KIR2DS3 also contributed significantly to
acute (HR 2.967, 95%CI, 1.265-6.958, p=0.012) and chronic GVHD (HR
2.541, 95%CI, 1.127-5.730, p=0.025). Conclusions. These data indicate
that prognosis after transplantation is associated with the numbers of
KIR ligands in recipients and T cell alloreaction may play a predominant
role in this model.
0187
DENDRITIC-LEUKEMIA CELL HYBRIDS GENERATE SPECIFIC ANTI LEUKEMIA CTLS IN
VITRO
R. Eshel, M. Shpringer, R. Ben-Yosef, A. Vexler, E. Naparstek
Tel-Aviv Sourasky Medical Center, TEL-AVIV, Israel
Background. Allogeneic stem cell transplantation (alloSCT) contributes
significantly to better disease control in patients diagnosed with high risk
AML. . Nevertheless, a significant proportion of patients suffer from
recurrence of the disease. For those high risk patients, novel therapeutic
strategies based on cellular immunotherapy have been explored to
improve the clinical outcome of alloSCT. However, in most cases the
leukemia specific antigens are unknown, and hence the cellular or nonantigen
specific immunotherapy is based preliminary on the administration
of allogeneic, donor derived T lymphocytes (DLI), aiming to induce
a clinically significant graft-versus-leukemia responses. Aims. The aim of
our study was to induce a potent and specific anti-leukemia cytotoxic
T lymphocyte (CTL) response, utilizing dendritic-leukemia cell hybrids,
to treat leukemic relapse in patients after alloSCT. Such fusion cell vaccine
has the advantage of presenting both known and unidentified
leukemic antigens, in the context of co-stimulatory signals. Methods and
Results. Purified human monocyte-derived dendritic cells (DCs) were
isolated from peripheral blood mononuclear cells of 5 healthy HLAidentical
stem cell donors. Immature DC were successfully fused with
recipients irradiated leukemic cells utilizing polyethylene glycol (PEG),
and underwent further maturation in the presence of TNF-α , IL-6 , IL-
1β , and PGE2. Fused population of DC-leukemia was estimated by
flow-cytometry using two membrane incorporated fluorescent dyes,
and DAPI stain was utilized to confirm the true presence of DC -
leukemia cell hybrids. Generation of leukemia specific donor CTLs was
performed by co-culture of donor mononuclear cells with irradiated
DCs-leukemia hybrids under IL-2 deprivation. T cells were then further
expanded in culture, and tested for their specific in-vitro cytotoxic activity
against the leukemia cells that was utilized as fusion partner by LDH
cytotoxicity colorimetric assay. In 4 out of 5 cases we were able to
demonstrate a significant and specific cytotoxic activity of the hybridsprimed
CTLs against the patients leukemic cells. Conclusions. Our results
clearly demonstrate that the hybrid vaccination approach in AML is
technically feasible. Such specific anti-leukemic donor CTLs may be utilized
to maximize the anti-tumor effects of DLI in patients relapsing
after allogeneic transplantation.
68 | haematologica/the hematology journal | 2007; 92(s1)
0188
TOLL-LIKE RECEPTOR EXPRESSION ON TRANSPLANTED T-CELL SUBSETS INFLUENCES
OUTCOME AFTER ALLOGENEIC UNRELATED STEM CELL TRANSPLANTATION
U. Platzbecker, J. Stoehlmacher, C. Pabst, Ch. Thiede, G. Ehninger,
M. Bornhauser
Universitätsklinikum Carl Gustav Carus, DRESDEN, Germany
Introduction. Recently, Toll-like receptor (TLR) 2 and 4 have been identified
as the most important receptors for LPS, which is contained in the
cell wall of gam-negative bacteria and is known to be a main inducer of
graft versus host disease (GVHD). The role of TLR expressing T-cells
within the graft for the induction of GVHD in patients after unrelated
peripheral blood stem cell transplantation (PBSCT) is unknown. Methods
and patients. We therefore determined by flow cytometry TLR
expression on T-cells within the graft of 63 patients receiving unrelated
PBSCT after intensive conditioning followed by cyclosporine A and
methotrexate as GVHD prophylaxis. Additionally, donor specific single
nucleotide polymorphisms (SNP) for TLR2-R753Q, TLR4-D299G and
TLR4-Y135A were determined. The data were finally correlated with
clinical endpoints. Results. As expected, TLRs were not significantly
expressed on T-cells in peripheral blood of healthy donors (TLR 2: