A G-CSF-primed PBPCI was planned within day 60 post-transplantation before hematologic relapse was diagnosed in patients for which no GVHD occurred or free of GVHD after 2 weeks off immunosuppression for patients receiving GPBPCI after day 90 post HSCT. Before administration of GPBPCI, serious infection had to be cleared and no serious organ failure could be present. The GPBPCI regimen was comprised of G-CSF-primed PBSCs instead of harvested non-primed donor lymphocytes and short-term immunosuppressive agents for prevention of GVHD after GPBPCI. Chimerism status was examined before and after prophylactic treatment with GPBPCI.