Peripheral dendritic cell chimerism in allogeneic hematopoietic stem cell recipients.
BACKGROUND
Relapse and graft-versus-host disease (GVHD) represent major causes of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HSCT). Although leukocyte and T-cell chimerism analyses are performed routinely suggesting a predictive value on the patients outcome, little is known about chimerism of dendritic cells (DC) representing strong initiators of immune responses.


METHODS
In this prospective study, peripheral DC1 (CD11c+) and DC2 (CD123+) chimerism was determined in hematopoetic stem cell recipients. DCs were isolated from peripheral blood by fluorescence activated cell sorting. Chimerism analyses were performed by fluorescent in situ hybridization or by polymerase chain reaction-based typing of short tandem repeats.


RESULTS
At time of engraftment, DC chimerism analyses showed complete chimerism in 76.3% (DC1)/79.5% (DC2), mixed chimerism (MC) in 21.0% (DC1)/17.9% (DC2) and no chimerism in 2.7% (DC1)/2.6% (DC2) of the patients. Peripheral DC chimerism had no significant effect on relapse-free or overall survival. Although acute GVHD was observed more often in patients with MC for DC1/DC2 and chronic GVHD occurred more often in patients with MC for DC2, there was no statistically significant correlation.


CONCLUSIONS
Although DCs as antigen presenting cells are supposed to have an impact on the induction of GVHD, there was no significant correlation between incidence of GVHD and DC chimerism after HSCT.
Pihusch
Markus
M
Abteilung fuer Haematologie und Internistische Onkologie, Klinikum der Universitaet Regensburg, Regensburg, Germany. Markus.Pihusch@t-online.de
Boeck
Stefan
S
Hamann
Moritz
M
Pihusch
Verena
V
Heller
Tatjana
T
Diem
Heinz
H
Rolf
Burkhard
B
Pihusch
Rudolf
R
Andreesen
Reinhard
R
Holler
Ernst
E
Kolb
Hans-Jochem
HJ
D000293:Adolescent; D000328:Adult; D046528:Chimerism; D003713:Dendritic Cells / Q000166:cytology*; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014184:Transplantation, Homologous; D016896:Treatment Outcome