Utilization of TREC and KREC quantification for the monitoring of early T- and B-cell neogenesis in adult patients after allogeneic hematopoietic stem cell transplantation.
BACKGROUND
After hematopoietic stem cell transplantation (HSCT) T- and B-cell reconstitution from primary lymphoid organs are a prerequisite for an effective early lymphocyte reconstitution and a long-term survival for adult patients suffering from acute leukemia. Here, we asked whether quantification of T cell receptor excision circle, (TREC) and kappa-deleting recombination excision circle (KREC) before and within six month after allogeneic HSCT could be used to measure the thymic and bone marrow outputs in such patients.


METHODS
We used a duplex real time PCR assay to quantify the absolute copy counts of TREC and KREC, and correlated the data with absolute cell counts of CD3+CD4+ T-cell and CD19+ B-cell subsets determined by flow cytometry, respectively.


RESULTS
By comparing two recently proposed naïve T cell subsets, CD31+ naive and CD31- naive T cells, we found a better correlation for the CD31+ subset with TREC level post alloHSCT, in line with the assumption that it contained T cells recently derived from the thymus, indicating that TREC levels reflected real thymic de novo production. Transitional as well as naïve B cells highly correlated with KREC levels, which suggested an association of KREC levels with ongoing bone marrow B cell output. CD45RO+ memory T cells and CD27+ memory B cells were significantly less correlated with TREC and KREC recovery, respectively.


CONCLUSIONS
We conclude that simultaneous TREC/ KREC quantification is as a suitable and practicable method to monitor thymic and bone marrow output post alloHSCT in adult patients diagnosed with acute leukemia.
Institute of Medical Immunology, Charité CVK, Berlin, Germany.
Angela
A
Mensen
Christoph
C
Ochs
Andrea
A
Stroux
Friedrich
F
Wittenbecher
Martin
M
Szyska
Luisa
L
Imberti
Simon
S
Fillatreau
Lutz
L
Uharek
Renate
R
Arnold
Bernd
B
Dörken
Andreas
A
Thiel
Carmen
C
Scheibenbogen
Il-Kang
IK
Na
D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism*; D004270:DNA, Circular / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D016176:T-Lymphocyte Subsets; D013601:T-Lymphocytes / Q000378:metabolism*; D014184:Transplantation, Homologous
D004270:DNA, Circular; D011948:Receptors, Antigen, T-Cell