PLT HLA class I expression of each donor is constant over time. For each donor with at least 4 measurements, specific HLA I expression is depicted for HLA-B8 (A), -B12 (B), and -B35 (C). For each donor, relative expression is presented as mean ± SD, and each measurement is depicted by one symbol. Differences between interindividual and intraindividual variation were calculated using an F-test. Statistical significance is depicted as ****P < .0001.