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

were older than 65 y) which can be compared to the natural incidence
of fatal cancer in our population. Conclusion. Previous researches
revealed that the risk of radiation induced cancer is much smaller than
the natural risk of cancer. Our results showed that increased numbers
of CT screening procedures has not been correlated with increased incidence
of secondary malignancies. Age was only predictive risk indicator
(p15 fold rise in the titers of IgG against HHV6 were detected
indicating reactivation of latent infection. Moreover, presence of
effector CD8 + CD7 - CD57 + T cells subset also indicate an acute immune
response to viral infection and chronic antigenic stimulation maybe due
to inability to suppress HHV6 reactivation. These findings could indicate
impaired function and expansion of CD7 + CD8 + memory T cells
during Dasatinib treatment. Interestingly, when treatment with Dasatinib
was stopped, the immunosupression reverted, and the immune
system was able to clear the virus without need for specific treatment
(Foscarnet or Ganciclovir). Dasatinib was reinitiated at a lower dose 1
month after discontinuation of the medication. Repeated analysis
demonstrated a decrease in the titers of IgG antibodies against herpes
6 virus. Conclusions. these clinical features reflect the need of memory
T cells surveillance to control chronic latent infections. Patients treated
with Dasatinib may develop reactivation of viral infections and require
greater surveillance to detect infectious complications. Tyrosine kinase
inhibitors dose modification could be sufficient to prevent immunosupression
in some patients.
1372
CORD BLOOD LYMPHOCYTE SUBTYPES IN TERM INFANTS
A. Roumiantsev, 1 E. Boyakova, 1 A. Schutieva, 1 S. Sabirova, 2
E. Podkolzina, 2 E. Karpova, 2 E. Spiridonova, 2 J. Rouminatseva, 1
O. Mayorova2 1 Research Center of Pediatric Hematology, MOSCOW; 2 Stem Cell Bank,
MOSCOW, Russian Federation
Background. Standards of public cord blood banking include volume
reduction of samples/ Investigation of cord blood specific features is
necessary for quality control and establishing new methods. Aim. Study
of immunological parameters of cord blood lymphocytes and influence
of cord blood volume reduction on number of lymphocyte subtypes.
Materials and methods. We evaluated cord blood samples from 30 term
newborns (37-42 weeks of gestation). Samples were collected from cord
vein using closed system, containing 35 ml of CPDA, 5-15 minute after
delivery. Lymphocyte subtypes were analyzed using flow cytometry
before and after volume reduction according to the New York cord
blood bank protocol. We found no differences in number of CD3 + lymphocytes
before and after volume reduction, and it was 17,9±1,44% and
19,2±1,4% from total nucleated cells, respectively. Number and ratio of
CD3 + CD4 + cells and CD3 + CD8 + cells after volume reduction has also not
changed and was: before volume reduction CD3+CD4+ cells-
12,62±1,12%, CD3 + CD8 + cells-5,62±0,53%; after volume reduction
CD3 + CD4 + cells-13,23±1,12%, CD3 + CD8 + cells-5,52±0,48% from total
nucleated cells. Number of natural killer cells (NK) - CD16 + CD56 + cellsin
native cord blood nucleated cells was 5,97±0,67% and significantly
raised after volume reduction-8,54±0,91% (p = 0,027). Number of
CD33 + CD13 + cells was 12,5±0,76% and it significantly increased
15,82±0,81% (p =0,005) after extraction. This is may be related to
greater granulocyte shedding (lost?) during volume reduction. Number
of active lymphocytes has not changed and was 0,40±0,08% before
and 0,38±0,09% after volume reduction. Number of CD14 + cells has not
raised and was 8,65±1,58% before and 9,11±1,76% after volume reduction.
We found a tendency to decreased CD15 + cells number after volume
reduction. This may be result of greater lost of this type of cells in
comparison with other leukocyte subtypes during volume reduction n.
Its number was 39,32±3,45% before and 35,23±3,26% after volume
reduction. Conclusion. We evaluated and characterized cord blood lymphocyte
subtypes and found no influence of cord blood concentration
method on CD3 + lymphocytes count. Number of NK-cells and
CD33 + CD13 + cells has significantly increased after procedure of volume
reduction.
haematologica/the hematology journal | 2007; 92(s1) | 493