Phase 1/2: CD45RA Depleted Stem Cell Addback to Prevent Viral or Fungal Infections Post TCRab/CD19 Depleted HSCT

Patients in the first dose level for the CD45RA depleted addback will receive 1 X 10\^6 CD45RO+ T cells/kg. Once all patients in this dose group have been evaluated for acute GVHD at day 100, then we will advance to the next dose level if indicated by safety analysis.

Patients in the second dose level for the CD45RA depleted addback will receive 2 X 10\^6 CD45RO+ T cells/kg. Once all patients in this dose group have been evaluated for acute GVHD at day 100, then we will advance to the next dose level if indicated by safety analysis.

"Patients in the third and final dose level for the CD45RA depleted addback will receive 5 X 10\^6 CD45RO+ T cells/kg. All patients in this dose group will be evaluated for acute GVHD at day 100. Based on these findings, the maximum tolerated dose (MTD) will be determined.~Once MTD for the addback cell dose has been determined in Phase 1, subjects with mismatched related donors will then enroll in Phase 2."

Patients with mismatched related donors will receive the CD45RA depleted addback at the maximum tolerated dose determined in the Phase 1 portion of the study.

Patients with unrelated donors will receive the CD45RA depleted addback at the dose 5 X 10\^6 CD45RO+ T cells.