Mechanism of low GVHD incidence in umbilical cord blood transplantation

Objective To compare the immunological function between umbilical cord blood (UCB) and peripheral blood, and to explore the mechanism of low incidence of graft\|versus host disease (GVHD) in UCB transplantation. Methods The proliferation assay,NK cell killing activity assay and immunologic fluorescence double label technique were used to study four sear effect on T cell immunologic function. Results UCB serum could reduce K 562 cell activity, compared to that of adult serum.Furthermore,adult serum will enhanced the percentage of HLA DR expression of T cells on PHA\|stimulated PBMC,whereas fetal serum has no such effect.Both adult and fetal serum enhanced mitogen\|specific T cell proliferation,the peak proliferative response could be reached with adult serum but not with fetal serum. Conclusion There must be some soluble factors secreted into serum,which play a role in T cell activation and associate with the incidence of GVHD.\;