HIGHLY SENSITIVE POLYMERASE CHAIN-REACTION METHODS SHOW THE FREQUENT SURVIVAL OF RESIDUAL RECIPIENT MULTIPOTENT PROGENITORS AFTER NON-T-CELL-DEPLETED BONE-MARROW TRANSPLANTATION

Twenty-four male patients grafted for various pathologies with the mar row of a female donor and presenting a complete donor-type hematopoies is when analyzed by polymerase chain reaction (PCR) amplification of m inisatellite sequences 33.6.3 and MS51 (0.1% to 1% sensitivity) were s tudied by the highly sensitive technique of PCR amplification of the Y -chromosome-specific DYZ1 sequence (0.01% sensitivity). Residual recip ient male cells were detected in all peripheral blood samples collecte d within 1 year posttransplantation. These residual cells were present in both the lymphocyte and polymorphonuclear cell fractions when such a separation was performed by Ficoll gradient centrifugation and, for samples of 13 of 15 patients, at comparable levels in both fractions. In 3 samples collected from 3 patients 4 months or more posttransplan tation, residual recipient cells were detected in the polymorphonuclea r cell fraction but were present at a lower level or were undetectable in the lymphocyte fraction. These cells are of hematopoietic origin b ecause they were detected at equivalent levels in whole blood and in B and T lymphocytes sorted with antibody-coated magnetic beads. They we re not detected in samples collected more than 15 months posttransplan tation for 6 of 7 patients. The persistence of residual recipient cell s within 1 year posttransplantation is not restricted to male patients receiving a transplant from a female donor because they were also det ected in 2 female patients using an allele-specific amplification meth od for the thyroid peroxydase gene that also has a high sensitivity (0 .01%). Our results indicate that at least residual recipient myeloid p rogenitors and possibly totipotent hematopoietic stem cells may surviv e intensive pretransplant conditioning regimen and support a transient residual hematopoiesis of the host posttransplantation. (C) 1994 by T he American Society of Hematology.