Differences in lymphocyte subpopulation count and function in cord, maternal and adult blood

Phenotypical characterization and functional activity of lymphocytes and natural killer (NK) cells in cord blood (CB) were investigated, and maternal peripheral blood (MPB) values were compared to those of adult peripheral blood (APB) (control).

To determine cytotoxic activity target cells (K562) were labeled with carboxyfluorescein diacetate (CFDA) or fluorescein isothiocyanate (FITC), and propidium iodide (PI) was used to label dead cells. Cell surface expression in CB, APB, and MPB cells were analyzed using flow cytometry.

CB and MPB mononuclear cells had similar CD45, CD34, CD4, and surface molecule for T helper cell expression, but had low-level expression of total T-lymphocyte surface molecules CD3 and CD8. CD19 and HLA-DR expression was higher in CB than in MPB. The same high-level of expression for CD19 and HLA-DR was observed in APB, as compared to MPB. All other cell surface expressions were similar in APB and MPB samples. NK (CD16+ and CD56+) cells in CB was similar to that in MPB and APB, and the level of inhibitory KIR receptors in NK cells was higher in venous CB than in MPB and APB. The only difference between MPB and APB was that the CD158a level was higher in MPB. No difference was observed in NK cells in CB and MPB, in terms of cytotoxicity.

The present results show that there was numerical and proportional variability of lymphocytes and their subgroups in CB and APB, but no cytological difference.