Objective To explore the immunogenicity of nonhematopoietic stem cells from human umbilical cord blood (HUCB). Methods We detected HLA-ABC, HLA-DR of HUCBnHSCs and HUCBnHSCs treated of IFN-γ for 3 days by FACS. Then CB-nHSCs, passage 1 CB-nHSCs, differentiated CB-nHSCs, CB-nHSCs treated with IFN-γ, human neuroblastoma cell line SH-SY5Y were co-cultivated respectively with spleen lymphocytes to observe proliferation of these lymphocytes.Results The HUCBnHSCs were positive for HLA-ABC, while few cells were positive for HLA-DR. The treatment of IFN-γ didn’t increase the expressions of HLA-ABC and HLA-DR. In mixed lymphocyte culture, they all failed to stimulate proliferation of lymphocytes except for the SH_