Comparisons of alloreactive potential of clinical hematopoietic grafts.
BACKGROUND: We sought to compare the immunoreactive potential of human cord blood (CB) versus normal adult bone marrow (BM) versus mobilized blood (peripheral blood stem cells; PBSC) from cancer patients. METHODS: Forty mice were randomized to receive a range of doses of T cell-replete cell preparations from one of the above three cell sources. Twenty-eight control mice underwent transplantation with T cell-depleted cells. Mice were observed for 60 days for the development of fatal xenogeneic graft-versus-host disease-like syndrome (GVHDLS). RESULTS: For the mice that had received T cell-replete grafts of CB or BM or PBSC, the duration of GVHDLS-free survival of the chimeras was inversely proportional to the number of T cells transplanted. After adjustment for the number of T cells transplanted, the relative hazard of developing fatal GVHDLS was 62-fold higher for PBSC and 210-fold higher for BM as compared with CB. Flow cytometric and histologic analyses of selected chimeras that died of GVHDLS showed extensive proliferation of human T cells in multiple organs. In contrast, mice that survived to day 60 were engrafted with human myeloid and B lymphoid cells. CONCLUSIONS: The immunoreactive potential, as measured by this in vivo assay, differed among clinical grafts: BM > PBSC > CB.