GESTATIONAL-AGE AND CELL VIABILITY DETERMINE THE EFFECT OF FROZEN STORAGE ON HUMAN FETAL HEMATOPOIETIC PROGENITOR-CELL PREPARATIONS

We have assessed hematopoietic progenitor cell preparations (including CD34-positive stem cells) obtained from human fetal liver at 6-17 wee ks of gestational age for total cell numbers, viability and the abilit y to tolerate (frozen) storage. Hematopoietic cell preparations obtain ed from the 16- to 17-week gestational age range had the highest total cell count and the greatest proportion of CD34-positive stem cells, H owever, these preparations were insufficiently robust to withstand the freeze/thaw protocol required. Cells obtained from the 13- to 15-week gestational age range showed optimal post-thaw viability and it is su ggested that these cell preparations are the most applicable for in ut ero transplantation.