Cytogenetic follow-up studies of recipients of T-cell depleted allogeneic bone marrow.

Serial cytogenetic studies of bone marrow and blood cells were made in leukaemic patients who had received an allogeneic bone marrow graft from a donor of unlike sex. The donor marrow was treated with the monoclonal antibody Campath-1 before infusion. The persistence of a significant proportion of dividing recipient cells in marrow and blood was observed after grafting. These recipient cells showed evidence of radiation damage of both the stable and unstable types. More than one transient clone of chromosomally abnormal recipient cells was observed in three cases. The differences between the cytogenetic findings in patients receiving donor marrow from which T cells have been removed and those cases previously studied in our Leukaemia Unit who had received untreated donor marrow are discussed.