Peripheral Blood Donor Cell Chimerism

Passenger leukocytes have been demonstrated to play significant roles in initiating and also regulating immune reactions after organ transplantation. Reliable techniques to detect donor leukocytes in recipients after organ transplantation are essential to analyze the role, function, and behavior of these leukocytes. In this report we describe a simple, reliable method to detect donor cells with low frequencies using peripheral blood samples. Detection of small numbers of major histocompatibility complex (MHC) mismatched cells was first studied using four-color flow cytometry in artificially created cell mixtures. By selecting the CD45 + population and simultaneous staining with several leukocyte lineage markers (CD3, CD4, CDS, CD56, and CD19), MHCmismatched leukocytes were consistently detected in cell suspensions prepared from directly stained whole blood samples with a threshold sensitivity as low as D.I %~ ABBREVIATIONS mAb monoclonal antibody PBMC peripheral blood mononuclear cells WB whole blood