Detection of functional immune reconstitution and posoleucel clones over time coincident with viremia reduction. Patient examples of viral load plotted with unique posoleucel clones detected by TCRβ sequencing (left panels) and functional IFN-γ⁺ virus-specific T-cell responses detected by ELISpot (posoleucel and endogenous derived; right panels) through week 26 of the study for patients with viremia of ≥1 target virus(es). Three patients with viremia that did not progress to CSI are shown: patient 1: BKV, EBV, and HHV-6 viremia (A-B; received all 7 doses of posoleucel); patient 2: BKV and EBV viremia (C-D; received all 7 doses of posoleucel); and patient 3: BKV, CMV, EBV, and JCV viremia (E-F; received all 7 doses of posoleucel). TCRβ clones unique to posoleucel are shown as the log₂ fold change of the sum frequency of clones relative to first time point detected. Virus-specific IFN-γ⁺–producing cells were measured by ELISpot after stimulation of patient PBMCs with AdV, BKV, CMV, EBV, or HHV-6 antigens (SFCs per 5 × 10⁵ PBMCs). All detectable viremia (viremia > LLOQ) is shown in the left panels with TCRβ sequencing data. In right panels with ELISpot data, only viremia for which there was corresponding ELISpot data is shown.