Decreased clonal diversity in CD8⁺ CD57⁺ T-cell populations from PNH patients. Percentage of different CDR3 sequences, and thus of different clones, in the CD8⁺ CD57⁺ T cells. Each symbol represents 1 healthy control subject or 1 PNH patient. Average and standard deviation are shown for the patient group (34.0% ± 9.6%) and for the control group (56.7% ± 12.1%); Mann-Whitney U test, P < .001.