DETECTION OF MATERNAL DNA IN HUMAN CORD-BLOOD STORED FOR ALLOTRANSPLANTATION BY A HIGHLY SENSITIVE CHEMILUMINESCENT METHOD

Human cord blood (CB), a rich source of hematopoietic stem and progeni tor cells, is currently used for bone marrow reconstitution. However, the level of contamination of CB with maternal cells that could provok e graft-versus-host disease (GvHD) is a matter of concern. In the pres ent study, 60 consecutive CB samples collected and stored in the Milan CB Bank, for which no maternal DNA was detected through genomic HLA t yping, were examined to ascertain maternal cell contamination using po lymerase chain reaction amplification of two minisatellites, apolipopr otein B gene (ApoB) and D1S80, followed by chemiluminescent detection. The sensitivity of the method employed in this study was 0.04%, compa rable to that of radioactive methods. A maternal specific allele was f ound in 11 of the 60 CB units, at a level ranging from 1:100 to 1:2500 . We could also detect the child paternal allele in 3 of the 30 mother s whose newborn was heterozygous at the loci examined. Our study indic ates that maternal cells are present in 18.3% of the 60 samples examin ed. The clinical relevance of such a presence remains to be establishe d. In our opinion, information on maternal cell contamination should b e included within the quality control tests performed before deliverin g a unit.