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

12 th Congress of the European Hematology Association
unrelated donor (MUD) PBSCT leads to a worse overall outcome and
higher incidence of severe GvHD in both adults or children in comparison
with well established MUD-BMT. It is well known that PBSC grafts
contain ca 1 log more mature T cells, which may result in higher rate of
severe often fatal acute/chronic GvHD after MUD-PBSCT. The aim of
our study was to compare the results of MUD-PBSCT vs MUD-BMT in
a large pediatric patient population. We analysed the records of 157
pediatric pts (ALL n=57, AML n=25, CML n=28, MDS/JMML n=14,
NHL/HD n=6 and nonmalignant disorders n=27), who underwent
MUD-BMT (39 pts) or MUD-PBSCT (118 pts) between 1999 and 2006
in our institution. Probability of overall survival for all pts after MUD-
PBSCT was 0.53 and after MUD-BMT was 0.45, whereas pDFS after
MUD-PBSCT was 0.53 and after MUD-BMT - almost significantly
worse 0.39 (p=0.07). Median follow up of surviving 90 pts (57%) was 2
years and of dead 67 pts was 4 months. Probability of DFS for pts after
MUD-BMT was for ALL 0.4, for AML 0.17 and for CML 0.67, respectively,
whereas it was much higher for pts after MUD-PBSCT for AML
0.69 (p=0.01 log-rank) and not lower for pts with ALL 0.38 and CML
0.56, respectively. Furthermore, there was no difference between the
incidence of both acute GvHD grade III-IV between the recipients of
MUD-PBSCT (19.5%) or MUD-BMT (20.5%) and extensive chronic
GvHD (19.6%for MUD-PBSCT recipients and 15.4% for MUD-BMT
recipients), respectively. In conclusion the results of MUD-PBSCT in a
large prospective pediatric cohort of pts are similar if not better that the
results of MUD-BMT. There seems to be no increased risk of severe
GvHD after MUD-PBSCT. MUD-PBSCT seems to offer a better disease
control in patients with malignancies, especially with AML due to more
pronounced T-cell mediated GvL effect.
0586
STUDIES IN C3 DEFICIENT MICE REVEAL BENEFICIAL ROLE OF COMPLEMENT IN
AMELIORATING CONSEQUENCES OF GRAFT-VERSUS-HOST DISEASE AFTER
HEMATOPOIETIC ALLOTRANSPLANTATION
O. Wiecha, 1 E. Lesko, 1 W. Miezynski, 1 L. Wojakowski, 2
M.Z. Ratajczak, 2 M. Majka1 1 Jagiellonian University Medical College, KRAKOW, Poland; 2 University of
Louisville, LOUISVILLE, USA
Graft-versus-host disease (GvHD) is the main complication after allogeneic
hematopoietic stem cell transplantation. Immunosuppressive regimen
used in its prevention and treatment is only partially effective making
research focusing on new possibilities for control of GvHD necessary.
While activation of complement during GvHD has been observed
there are no published data concerning its significance for GvHD pathophysiology.
The aim of the study was to evaluate the role of complement
in pathogenesis of GvHD by employment of C3 knock-out animals.
C3 +/+ (n=90) and C3 -/- (n=74) mice from the C57/BL6 background
were transplanted with 5×10 6 BM cells and 4×10 6 or 10×10 6 splenocytes
isolated from allogeneic H2 and sex mismatched C3H mice or from
C57/BL6 syngeneic animals(21 C3 +/+ , 22 C3 -/- ) one day after ablative TBI.
Mice were weighted and physically examined by looking for changes
in skin, posture, physical activity and chimerism in transplanted animals
was confirmed by detection of sry gene with real-time PCR. Peripheral
blood morphology assessment and fluorocytometric analysis of
peripheral blood lymphocytes were performed for some animals on
days +17, +31 and +45. Histopathological examination was performed
in randomly chosen animals on day +8 and +16 and furthermore on
most of mice which died during the experiment. Evident physical
(weight loss, skin desquamation, hunching) and histopathological
(involvement of liver, skin, spleen and gut) symptoms of GvHD were
observed in all mice transplanted with allogeneic cells but not in mice
transplanted with syngeneic cells. Analysis of peripheral blood of allotransplanted
animals revealed severe lymphopenia affecting B and T
cells, strongly increased expression of CD69 activation antigen on CD4 +
and CD8 + cells and lower values of RBC, Hb, Hct and MCV as compared
to syngeneic controls. The most important difference between C3 -/- and
C3 +/+ allogeneic graft recipient populations was significantly worse survival
of C3 deficient animals (median: 50 vs. 63, mean: 112 vs. 158 days,
hazard rate=1.62, p=0.028; Figure 1). Characteristic pattern of weight
loss was observed consisting of a fall to ca 86% of initial body weight
on day +7 followed by return to the initial weight on days +14 to +17
and another decrease in weight leading either to the death of the animal
or to a long time plateau. The average weight of C3 -/- animals was
significantly lower on day +10 as compared to C3 +/+ mice (90,1% vs.
93,7%, p=0.002). Interestingly, the body weight on day +10 was strongly
correlated with overall survival (p=0.001). Blood examinations
revealed higher WBC count in C3-/- knock-out mice on day +45 (19 vs.
218 | haematologica/the hematology journal | 2007; 92(s1)
11×10 3 /uL, p=0.024). Skin changes tended to be less severe in wild type
animals but observed differences were not statistically significant. This
study showed for the first time the beneficial role of the complement
cascade in ameliorating consequences of GvHD in mice. The positive
influence of the cascade on the overall survival is particularly interesting
because of its potential clinical implications. In the light of our data,
assessment of the role of complement in the course of GvHD in transplanted
patients could be interesting in the future.
Figure 1. Kaplan-Meier survival curves for populations of C3 -/- (ko) and C3 +/+
(wt) mice transplanted with allogeneic (allo) and syngeneic (syn) cells.
0587
A COMPARISON OF THE CYTOTOXIC EFFECTS OF 4 COMMERCIALLY AVAILABLE PREPA-
RATIONS OF ANTI-T CELL GLOBULINS IN VARIOUS HEMATOLOGICAL MALIGNANCIES
A. Ayuk, N. Maywald, S. Hannemann, U. Larsen, A.R. Zander,
K. Nicolaus
University Medical Center Hamburg, HAMBURG, Germany
Background. Polyclonal anti-T-cell globulins (antithymocyte globulins),
ATGs are widely used in allogeneic stem cell transplantation mainly due
to their anti-T cell activity. ATGs however contain a wide range of antibodies
targeting antigens expressed on various hematopoetic cells. Lymphoglobulin
® and Atgam ® are produced by immunizing horses with
human thymocytes. Thymoglobulin ® is produced by immunizing rabbits
with human thymocytes, while ATG-Fresenius ® is produced by
immunizing rabbits with the jurkat cell line. We have previously reported
potent ant-myeloma activity of ATG-Fresenius ® . Similar data were
later reported for Thymoglobulin ® . Various ATG preparations have been
shown to induce apoptosis in malignant B cell lines. Future conditioning
regimens may therefore take advantage of the direct effects of ATGs
against hematological malignancies. Aims and Methods. We sought to
compare the cytotoxic activity of 4 commercially available ATG preparations
in myeloma cell lines and myeloma patient samples, B-NHL cell
lines and CLL patient samples, myeloid leukemia cell lines as well as primary
T cell samples. Viability was assessed by staining with 7AAD and
subsequent flow cytometry. Results. In all, Atgam ® showed significantly
lower anti-T cell activity compared to the other 3 ATG preparations.
Atgam ® also showed significantly lower anti-leukemia activity compared
to the other 3 ATG preparations. The anti-CLL effect of Thymoglobulin
® was twice as strong as that of ATG-Fresenius ® .Thymoglobulin
® , ATG-Fresenius ® and Lymphoglobulin ® had similar anti-myeloma
activity. Thymoglobulin ® , ATG-Fresenius ® and Lymphoglobulin ®
showed potent complement-mediated cytotoxicity against myeloid
leukemia cell lines but no significant complement independent cytotoxicity
could be observed against myeloid leukemia cell lines. Conclusions.
Our data show that Thymoglobulin ® , ATG-Fresenius ® and Lymphoglobulin
® have potent cytotoxic effects against myeloma, CLL and other B
cell lymphomas, but limited activity against myeloid leukemia. These
findings would be helpful in choosing the ATG preparation and dose
when targeting hematological malignancies.