Age, aGVHD, and cGVHD have an independent effect on thymic function recovery. Mean ± SE number of sjTREC/mm³ of blood was measured by quantitative PCR, before and 3, 6, and 12 months after transplantation, in the PBMC of patients younger (A) or older (B) than 25 years, with (, plain gray lines) or without aGVHD (●, dotted black lines) or in all patients (C) with aGVHD (gray lines and symbols) and cGVHD (dotted lines, squares). *P < .05; ** P < .01.