aGVHD-induced delay in thymic function recovery is not primarily due to a default in intrathymic proliferation. Number of sjTREC/150 000 PBMC (A), Dβ-JβTREC/150 000 PBMC (B), or sj/βTREC ratio (C) was measured by quantitative PCR, in 25 normal blood donors, including 3 cord blood samples and plotted against age. Mean ± SE number of sjTREC/150 000 PBMC (D), Db-JbTREC/150 000 PBMC (E), or sj/βTREC ratio (F) was measured by quantitative PCR before and 3, 6, and 12 months after graft, in the PBMC of 20 patients with (, plain gray lines) or without aGVHD (●, dotted black lines). * P < .05.