Recognition of individual CMV epitopes among HCT recipients who reactivated or did not reactivate CMV in the first 100 days after hematopoietic cell transplantation. Each row represents a unique CMV peptide, and peptides are ranked in descending order of frequency of recognition among all participants. Each labeled column (eg, P1) contains 2 samples, one from the recipient pre-HCT (pre-R, lighter bars within each color) and the other at 100 days post-HCT (d100, darker bars). Participants with seropositive donors (D⁺) are on the left, further stratified as to whether they demonstrated CMV reactivation before d100 (≥100 copies of CMV per milliliter by plasma PCR or ≥2 cells positive for CMV pp65/2 × 10⁶ cells), reactivators in blue (n = 15) and nonreactivators in magenta (n = 8). Participants with seronegative donors (D⁻) are also stratified by CMV reactivation (purple; n = 4) or no reactivation (red; n = 4). Visually, those who reactivated (either D⁺ or D⁻) generally expressed more CMV epitopes. There was a trend toward reactivators having more heterogeneity in expressed epitopes before and after reactivation (42.1% vs 8.3%, P = .1). Three participants (P3, P4, and P25) who had confirmed diagnoses of CMV disease, which was gastrointestinal disease in all cases, are annotated with an asterisk. Six of 37 participants who were missing either sample are not displayed.