 While ECP has been used in 106 patients as part of a reduced intensity conditioning regimen, it is unknown whether adding ECP to pentostatin and radiation is what caused the reduced rate of GVHD that was seen in the previous study that was done. The use of ECP as part of a conditioning regimen is investigational. ECP is approved by the U.S. Food and Drug Administration FDA for the treatment of cutaneous T-cell lymphoma, but is not approved by the FDA for use prior to ASCT. 