CTL product clones are detected in patients through 6 months after infusion. The figure on the left shows the frequencies of the subset of SARS-CoV-2–specific CTL donor sequences present in both the patients’ baseline samples and the CTL donor product (CTL donor-patient overlap). The figure on the right excludes all these overlap clones detected at baseline and shows only donor CTL clones that were not present in the patients’ preinfusion samples. These were used to assess the frequency of donor CTLs over time. Sequences were tracked at the DNA, not amino acid, level. All four 6-month samples exhibited low but nonzero frequencies of CTL product clones undetected preinfusion. Clones most consistent with donor-derived CTLs were detected in patient 5 on dosing level 2 at day +28, but lack of baseline sample in this patient precludes definite confirmation. Testing performed by Adaptive Biotechnologies. D, day; M, month.