Background: Cord blood is practical source hematopoietic stem cells for transplantation. However, there are concerns that cord blood might be contaminated with maternal cells that could lead to graft-versus-host disease.
Material and Methods: In the present study, we used the polymerase chain reaction(PCR) amplification of two minisatellite sequences(YNZ 22 AND 33.6)and fluorescence in situ hybridization(FISH), to ascertain the presence of maternal cells in the cord blood.
Result: The results were as follows;
1)Maternal-specific allele was present in 1 of the 16 cord bloods (6.25%) by PCR.
2)We determined the sensitivity of this methods for detecting a maternal specific allele in the cord blood sample, which demonstrated as 0.2% (YNZ 22 AND 33.6).
3)Maternal cells were found in 11 of the 20 cord bloods(55%), and 35 XX maternal cells in the 11 positives was 0.1~8.6% and median value of maternal cells was 0.2%.
Conclusion:These results suggest that maternal cells are very rarely present in the cord blood collected at birth. However, although small, this amount of cells may result in GVHD in a susceptible recipient. These methods we used allow the detection of maternal cells within female blood from 104 nucleated cells by FISH but it was difficult to detect matenal cells within female cord blood by PCR, then it needs the use of a more reliable tool in a cord blood banking perspective.

Keywords: Cord blood, PCR, FISH, Contaminated with maternal cells