Event-free survival. (A) Event-free survival by age at transplantation. The 5-year probabilities of event-free survival for patients aged ≤6 years, 7 to 15 years, and 16 to 25 years were 86% (83% to 89%), 80% (76% to 84%), and 63% (48% to 78%), respectively. (B) Event-free survival by donor type. The 5-year probabilities of event-free survival after HLA-matched relative, HLA-mismatched relative, HLA-matched unrelated, and HLA-mismatched unrelated donor transplants were 86% (83% to 88%), 70% (61% to 79%), 82% (75% to 89%), and 78% (70% to 86%), respectively.