[Hematopoietic stem/progenitor cells and phenotypes of lymphocyte subpopulations in human placenta]

To study whether human placenta contains hematopoietic stem/progenitor cells (HSPCs), and analyze phenotypes of lymphocyte subpopulations in the placenta.

Nucleated cells from fresh human placenta were analyzed for phenotypes of HSPCs and lymphocyte subpopulations by flow cytometry (FCM). And CD(34)(+) cells were sorted from human placenta nucleated cells by FCM or MiniMACS.

(1) CD(34)(+) cells, CD(34)(+)/CD(38)(+) cells, and CD(34)(+)/CD(38)(-) cells from a human placenta were 8.8, 4.6 and 11.9 times higher than those from umbilical cord blood (UCB), respectively. (2) The yields and purity of CD(34)(+) cells isolated from human placenta by FCM sorting system were (63.05 +/- 10.14)% and (86.39 +/- 11.27)%, respectively. (3) Lymphocytes, T cells (CD(3)(+)/CD(2)(+)), B cells (CD(19)(+)), Th cells (CD(3)(+), CD(4)(+)), and Th/Ts ratio in the placenta tissue were apparently lower than those in the UCB, while the CD(8)(+)/CD(28)(-) T suppressor cells were higher in the placenta than in the UCB.

Human placenta is rich in HSPCs, and has important hematopoietic function in ontogeny. It is probable that human placenta would be graft resource for HSPCs transplantation. CD(8)(+)/CD(28)(-) T suppressor cells might play an important role in feto-maternal immunologic tolerance.