<qa>  What is the prophylaxis of GVHD?- Graft-vs-host disease GVHD prophylaxis: Patients receive tacrolimus orally every 12 hours or IV continuously beginning on day -2 and continuing until day 90, followed by a taper until day 180. Patients also receive methotrexate IV over 15-30 minutes on days 1, 3, 6, and 11. 