Evaluating hematopoietic chimerism following allogeneic peripheral blood stem cell transplantation with microsatellites.
OBJECTIVE
To study the feasibility of using five selected tetranucleotide repeat sequences to detect chimerism in patients who underwent allogeneic peripheral blood stem cell transplantation and the correlation between chimerism status and prognosis in patients.


METHODS
Genomic DNA of umbilical cord blood was colleted from 140 normal neonates. 5 loci including CSF1PO, D3S1359, D5S818, D17S1293 and D20S161in each sample were amplified with polymerase chain reaction  PCR  . PCR products were electrophoresed on PAGE gels  For each locus  fragments of different size were collected to analyze polymorphism  Genotypes of each sibling undergoing transplantation were analyzed at every locus to determine chimerism  For sex-mismatched transplantation  the amelogenin locus was analyzed to discriminate between kappa and Y chromosome  The correlation between chimerism and prognosis was studied.


RESULTS
The four polymorphic symbols including the number of alleles and genotypes  the percentage of heterozygosity for each locus were as follows:for CSF1PO, 7 alleles and 16 genotypes were found; heterozygosity were separately 69.03%, for D3S1359, 12,26, 76.79%; for D5S818, 8, 21, 81.67%; for D17S1293, 12, 28, 79.09%; for D20S161, 7,17,79.67% and 0.7250  There were 12 complete chimeras of which one died from graft-versus-host disease. One mixed chimera died two weeks following a second transplantation. The patient who had no donor-derived cells died too  The one whose chimerism transformed from mixed to complete after a second transplantation had no evidence of relapse. We could not determine which kind of chimerism the other two patients were.


CONCLUSIONS
Chimerism after transplantation can be detected successfully with the five tetranucleotide repeat sequences  Every kind of chimerism has its respective prognosis  As the donor-derived cells decrease, the prognosis is becoming worse.
Department of Hematalogy First Hospital, Peking University  Beijing 100034  China.
Yali
Y
Ren
Ping
P
Zhu
Minmin
M
Xiao
Et Al
D046528:Chimerism; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D018895:Microsatellite Repeats; D036102:Peripheral Blood Stem Cell Transplantation; D016133:Polymerase Chain Reaction; D018183:Transplantation Chimera; D014184:Transplantation, Homologous