In vitro cord blood immune suppression

Chicago, IL -

The ability to use allogeneic cord blood transplants, without immune suppression is under great discussion. On the one hand, it is a fact that administration of allogeneic cord blood does not elicit GVHD when administered to non-immune suppressed patients (type "Bhattacharya N" and "cord blood" in pubmed for example papers). On the other hand, some believe that the allogeneic cord blood gets rapidly cleared by the immune system without having a chance to mediate therapeutic effects.

In a study that appeared today (Zhao et al. Immune regulation of T lymphocyte by a newly characterized human umbilical cord blood stem cell. Immunol Lett. 2006 Nov 27), the ability of cord blood stem cells to inhibit T cell proliferation was reported.

The paper stated that coculture of cord blood stem cells with PHA stimulated T cells resulted in an inhibition of T cell proliferation, which was associated with suppression of STAT5 phosphorylation.

The mechanism of suppression was associated with release of nitric oxide, as well as expression of PD1-L on the surface of the cord blood cells. Inhibition of TGF beta or prostaglandin E-2 did not alter suppression of T cell proliferation.

This paper in essense provides some in vitro data as to how cord blood transplants may actually be tolerogenic.

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