Engraftment of CD14⁺ donor monocytes (▪), CD15⁺donor neutrophils (•), and percent cells positive for surface expression of interferon-γ receptor-1 on donor CD14⁺monocytes (▴). Graft rejection was prevented by infusion of escalating doses of donor lymphocytes. Following full donor stem cell engraftment, surface expression of the interferon-γ receptor progressively diminished. Downward pointing arrows indicate microsatellite chimerism data prior to transplantation (accompanied by the donor pattern) day 134 and day 296 following the transplantation.