Association between pretransplantation TREC values and survival. Kaplan-Meier representatives of patient survival. (A) Patients (n = 62) were categorized in 5 groups of equal number according to pretransplantation TREC level (ranges are TRECs per 150 000 CD3⁺ cells: 0-18, solid gray line; 19-83, dashed gray line; 84-171, dotted gray line; 172-927, solid black line; and 928-7000, dashed black line). A first cohort (n = 62) and a confirmatory independent cohort (n = 40) of genoidentical HSCT patients were further split into “high” (≥ 172 TRECs/150 000 CD3⁺ cells; black lines) and “low” (< 172 TRECs/150 000 CD3⁺ cells; gray lines) groups, and analyzed separately (B and C, respectively) and together (D).