TREC recovery in the presence or absence of extensive chronic GvHD.

TRECs per 10⁶ PBMCs were measured and plotted (y-axis) for samples from patients who had developed extensive chronic GvHD (n = 10; ○, dashed line) versus those who had developed either limited chronic GvHD or none at all (▪, solid line), as a function of time from transplantation. Three patients had more than one TREC measurement, giving a total of 18 samples from this group of 10 patients. There was a highly significant difference between the 2 groups (P < .01). Note that the lower limit of detection for TRECs was 100 TRECs/10⁶ PBMCs in the assay used.