ALLOGENEIC RESPONSES OF HUMAN UMBILICAL-CORD BLOOD

Human umbilical cord blood (CB) is increasingly used as an alternative to bone marrow as a source of stem and progenitor cells for pediatric patients. We have evaluated the alloreactive potential of cord blood T cells in vitro. Our findings demonstrate that in a primary mixed leu kocyte culture CB T cells demonstrate strong proliferative responses t o allogeneic stimulation but little to no generation of cytotoxic effe ctor function, Furthermore, restimulation of primary cultures results in a state of proliferative unresponsiveness. Such diminished cytotoxi c and proliferative responses may, in part, be related to the low inci dence of graft vs. host disease thus far noted in human CB transplants ,