Partially Matched Stem Cell Transplantation for Patients With Refractory Severe Aplastic Anemia or Refractory Cytopenias

Participants will receive a reduced intensity conditioning regimen consisting of fludarabine, thiotepa, melphalan, and OKT3 followed by an infusion of haploidentical stem cells. Rituximab will be administered within 24 hours of the infusion in an effort to prevent posttransplant lymphoproliferative disorder LPD. In addition to T-cell depletion of the donor product, participant will receive mycophenolate mofetil for prophylaxis of GVHD.