Abstract
The proliferative state of human pluripotent hemopoietic progenitors (CFU-GEMM) was assessed in normal bone marrow transplant donors and in recipients after engraftment using the tritiated thymidine suicide method. In contrast to BFU-E and CFU-C, CFU-GEMM were found to be quiescent. In samples obtained during early regeneration after transplantation, CFU-GEMM were significantly reduced after short-term exposure to 3H TdR when compared to controls. This observation suggests active participation of CFU-GEMM in bone marrow regeneration.