Several studies suggest that the infused T cells need room to be able to proliferate and accomplish their functions and that this may not happen if there are too many other T cells in circulation. Because of that, participants will receive treatment with cyclophosphamide (Cytoxan) and fludarabine for 3 days before receiving the T-cell infusion. These drugs will decrease the numbers of the participants' own T cells before the investigators infuse the GAP T CELLS.