Evaluating hematopoietic chimerism following allogeneic peripheral blood stem cell transplantation with...

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.

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.

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.

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.