Activated and phenotypically memory, including T stem cell memory and MAIT, CD8⁺ T-cell subsets dominate early immune reconstitution in patients treated with PTCy. All 20 patients treated in a prospective study¹⁹  of reduced intensity conditioning HCT, as well as all 15 donors who consented for research, had immunophenotyping performed on fresh blood at serial time points to assess the relative composition of recovering CD8⁺ T-cell subsets. The 1 patient with primary graft failure was excluded from analysis. (A-B) CD8⁺ T cells were first gated as CD25⁺ or CD25⁻, and then the CD25⁻ cells were subgated into the other subsets. (A) Median values at each time point are shown to provide the overall relative CD8⁺ T-cell composition. (B) For each CD8⁺ T-cell subset are shown the percentages data over the serial timepoints from all patients. (C) Markers to identify MAIT cells were on a separate panel that was run if sufficient cells were available. Therefore, recovery of CD161⁺TCR-Vα7.2⁺ MAIT and CD161⁺TCR-Vα7.2⁻ non-MAIT cells are included separate from the other 6 subsets shown in (A).