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[Variable number of tandem repeats as an evidence of engraftment status after allogeneic peripheral blood stem cell transplantation].

OBJECTIVE
To evaluate engraftment status of patients after allogeneic peripheral blood stem cell transplantation (allo-PBSCT) based on red blood cell type, karyotype and variable number of tandem repeats (VNTR).


METHODS
Amplification of 3 loci of VNTR in vitro by polymerase chain reaction (PCR) was preformed to detect the polymorphism of 15 patients post-PBSCT. Furthermore, analysis of karyotype in 7 sex-mismatched patients and red blood cell antigen switching in 3 ABO blood type mismatched patients were also employed.


RESULTS
VNTR analysis in 15 patients revealed complete chimerism in 11 patients and mixed chimerism in 4. In the 7 sex-mismatched patients, karyotype analysis showed types of their donors. As for blood type analysis, it was after 2 months that the first patient transformed to his donor's type. One patient showed mixed status 7 months after transplantation.


CONCLUSION
Amplification of VNTR loci by PCR for documenting engraftment status after allo-PBSCT is simple and sensitive. This technology is especially suitable for patients who have received stem cells with the same sex, same blood type and identical HLA type. Examination with several different VNTR loci will improve the power of discrimination.