Correlation analysis of TREC quantification with T-cell subset recovery after alloHSCT. (A,C,E) PBMCs of adult alloHSCT patients were analyzed for absolute CD4+CD3+ T-cell subset counts by flow cytometry and absolute TREC copy number by quantitative RT-PCR before (preTx) and after transplantation at the indicated time points (preTx n=7, D15 n=11, D30 n=13, D60 n=8, D90 n=13, D180 n=8). Mean values of TREC copy number per ml blood (grey line, A,C,E) and absolute number of CD31+ naive (A), CD31- naïve (C) and memory T cells (E) per ml blood (black line) ± standard error of the mean (SEM) are shown. (B,D,F) Absolute TREC copy number and T-cell subset count are shown as scatterplot depiction with linear regression line for CD31+ naive (B), CD31- naïve (D) and memory T cells (F). The regression coefficients beta (β*) and p-values are displayed for each subpopulation.