Evidence for lack of conversion of CD4⁺ T cells in TILs into CD4⁺ Tregs after adoptive transfer. (A) Cell-surface expression of the mouse TCRβ chain was analyzed on PMBCs from a representative patient (1 week to 15 months) from the gp100 TCR trial. Numbers indicate the percentages in each quadrant. The week-1 figure is a representative sample of 1 of 16 week-1 samples analyzed. Nonparametric correlation between the percentages of Tregs and persistent (mTCRβ⁺) or nonpersistent (mTCRβ⁻) CD4⁺ T cells from week-1 PBMCs in the gp100 trial (B), the percentages of Treg and CD4⁺ T cells from week-1 PBMCs in the CD8⁺ young TIL trial (C), and the percentages of Treg and persistent or nonpersistent CD8⁺ T cells from week-1 PBMCs in the gp100 TCR trial (D). Spearman r and P values are shown.