Maternal plasma or human serum albumin in wash buffer enhances enrichment and ex vivo expansion of human umbilical cord blood CD34+ cells

Umbilical cord blood is a valuable source of haemopoietic stem/progenitor cells (HSC) for transplantation. This study explored the effect of maternal plasma/human serum albumin (HSA) in the purification and culture conditions of CD34 + cells derived from human umbilical cord blood. During CD34 + cell enrichment, including maternal plasma or HSA instead of fetal bovine serum (FBS) in the wash buffer, significantly increased the purity and the fold expansion of CD34 + cells. The increase in fold expansion of CD34 + cells was independent of CD34 + cell purity before expansion. With FBS, the mean fold expansion of CD34 + cells and total nucleated cells on day 7 was 9·7 ± 5·5 and 39·7 ± 13·7 respectively. The use of maternal plasma increased the mean fold expansion of CD34 + cells and total nucleated cells on day 7 to 28·2 ± 6·7 and 71·5 + 15·4 respectively. When HSA was added to wash buffer, the mean fold expansion of CD34 + cells and total nucleated cells were 30·4 ± 10·5 and 83·5 ± 24·8 respectively. No statistical significance was found between using HSA and maternal plasma on total cell and CD34 + cell expansion. We propose that HSA in maternal plasma was responsible for the positive effect on CD34 + cell enrichment and expansion.