Thymic function remains diversified following AHSCT, despite the occurrence of cGVHD. (A) Checkerboard representation of peripheral blood RTE repertoire diversity in controls (left) and AHSCT patients (GVHD^-: middle; cGVHD⁺: right). TCR Dβ1Jβ1.1 to Jβ1.6 TREC frequencies were enumerated by real-time quantitative PCR on 10⁵ peripheral blood mononuclear cells. Black squares represent detected (≥ 1 per 10⁵ cells) DβJβ TREC families, whereas empty squares correspond to frequencies of less than 1 DβJβ TREC per 10⁵ cells. In order to perform statistical analysis, a binary code was applied to the data set; “1” and “0” represent “detected” and “undetected” DβJβ TRECs, respectively. Statistical significance in the representation of TCR DβJβ TREC families among the 3 experimental groups is shown on top. Similar results were obtained in a duplicate experiment (not shown). (B) Positive association between peripheral sjTREC frequencies and the number of detectable Dβ1Jβ1.1 to Jβ1.6 TREC families. Empty triangles (▵) correspond to healthy control adults, whereas empty (▴) and filled (•) circles represent cGVHD^- and cGVHD⁺ AHSCT patients, respectively. Solid lines (—) indicate linear regression curves for each study group (top: controls; middle: GVHD^-; bottom: GVHD⁺).