Global burden of immunosuppression. (A) The cumulative incidences of initiation of a corticosteroid (left panel), CNI (center panel), or any nonsteroidal systemic pharmacologic or phototherapeutic immunosuppressant agent including a CNI (right panel) are shown for each of the 4 groups: BuCy conditioning with MRD allografting, BuFlu conditioning with MRD allografting, BuCy conditioning with MUD allografting, and BuFlu conditioning with MUD allografting. These analyses included immunosuppression (IS) use for any reason including treatment of acute or chronic GVHD, treatment of engraftment syndrome, treatment of GVHD occurring after DLI or second allogenic transplant, and prophylaxis for second allogeneic transplant in those requiring it for graft failure or relapsed disease. The only competing risk for these cumulative incidence curves was death. (B) The number of immunosuppressive agents with which each patient was being treated at the end of each 30-day interval is shown throughout the first posttransplant year for each of the 4 groups. No patients ever required >4 agents simultaneously. (C) For each of the 4 groups, multistate modeling shows the instantaneous probability of being in 1 of 3 states: (1) alive, not on immunosuppression (Alive, No IS), (2) alive, on immunosuppression (IS), or (3) dead (Death). All patients started in state 1 on day +5 of transplant after receiving cyclophosphamide 50 mg/kg per day on posttransplant days +3 and +4. Patients could transition between the states of being alive and on or off immunosuppression, but death was an absorbing state.