Detection of donor and host cells after in vitro responses to different stimuli. (A) A representative FISH analysis performed on PBMCs of UPN688 after culture with PPD. The arrow indicates the biotinylated pY3.4 probe complementary to a part of Y chromosome, showing the presence of some recipient cells. (B) RFLP-VNTR analysis performed on PBMCs of the donor (D) and the respective recipient UPN855 (H) pretransplant, on PBMCs of the host after culture with cells of a third party (A), and on the PBMCs of the same transplanted recipient after in vitro culture with TT (T), PPD (P), and PHA (Ph). The top arrow indicates the presence of recipient cells and the bottom arrow indicated the presence of donor cells. (C) Data summary in which the y-axis shows the percentage of donor cells evaluated by FISH or RFLP-VNTR and the x-axis shows the different samples analyzed before (PBMC) and after (PHA, PPD, TT, and Allo) in vitro culture. Different color bars refer to the 3 different patients (see legend).