Effect of patient age on survival among patients conditioned with CY/ATG/TBI and who received a transplant from HLA-identical donors. (A) Five-year survival among 33 patients 20 years old or younger was 73%, compared with 46% among 22 patients older than 20 years (P = .05). (B) Among patients conditioned with 200 cGy TBI, the survival figures were 78% and 50% for patients 20 years old or younger and for patients older than 20 years, respectively. (C) Survival among 23 patients aged 20 years or younger, conditioned with 200 cGy TBI, with disease duration of 1 year or less (70%) or longer than 1 year (85%).